Sample processing method and apparatus

A method of processing a sample comprises etching the sample by means of an etching plasma, and then treating the sample by means of a second plasma to remove residual corrosive compounds formed by the etching plasma. Removal of the residual corrosive compounds and prevention of corrosion is much improved by contacting the surface of the sample after the second plasma treatment with at least one liquid in order to effect at least one of (a) removal of the residual corrosive compounds and (b) passivation of the surface, and drying the sample.

 

What we claim is:

1. Apparatus for processing a sample, comprising

(i) means for effecting plasma etching of the sample, including supply means adapted to supply a first plasma-forming gas for the plasma etching,

(ii) means for effecting plasma treatment of the sample after the plasma etching, including supply means for supplying a second plasma-forming gas of the plasma treatment, said second gas being different from said first gas,

(iii) means for contacting the surface of the sample exposed by the plasma etching and the plasma treatment with a liquid adapted to effect at least one of (a) removal of residual corrosive compounds formed in the plasma etching and (b) passivation of said surface, and

(iv) means for drying said sample following contact with said liquid,

said apparatus further including means for transferring the sample from said means for contacting with a liquid to said drying means.

2. Apparatus according to claim 1 wherein said means for plasma etching comprises a first chamber and means for forming a plasma therein, and said means for effecting plasma treatment comprises a second chamber, which is different from said first chamber, and means for forming a plasma therein.

3. Apparatus according to claim 2 including means for transferring the sample from said first chamber to said second chamber.

4. Apparatus according to claim 2 wherein said means for plasma etching is a magnetic field-type microwave plasma etching apparatus.

5. Apparatus according to claim 2 wherein said means for plasma treatment is a non-magnetic field-type microwave plasma etching apparatus.

6. Apparatus according to claim 2 having a sample transfer station between said means for effecting plasma treatment and said means for contacting with a liquid, and having transfer means comprising a rotatable arm adapted to transfer the sample from said first plasma chamber to said second plasma chamber and from said second plasma chamber to said sample transfer station.

7. Apparatus according to claim 1 having a sample receiving station for receiving a sample to be processed and a sample discharge station for discharging a sample after the processing, said sample receiving station and said sample discharge station being on the same side of the apparatus.

8. Apparatus according to claim 1, wherein:

said means for effecting plasma etching comprises a plasma etching chamber; and

said means for effecting plasma treatment comprises a plasma treatment chamber;

said apparatus further comprising;

a loading chamber adjacent said plasma etching chamber;

an unloading chamber adjacent said plasma treatment chamber;

a first rotatable arm for transferring the sample from said loading chamber to said plasma etching chamber; and

a second rotatable arm for transferring the sample from said plasma etching chamber to said plasma treatment chamber and from said plasma treatment chamber to said unloading chamber;

wherein said first rotatable arm and said second rotatable arm are disposed so as to enable the sample to be transferred form said loading chamber to said unloading chamber along a predetermined path.

9. Apparatus according to claim 8, wherein rotary axes of said first and second rotatable arms are respectively disposed on opposite sides of said predetermined path.

10. Apparatus according to claim 8, wherein said first and second rotatable arms are rotatable in a common plane.

11. Apparatus for processing a sample, comprising

(i) means for effecting plasma etching of the sample, including supply means adapted to supply a first plasma-forming gas of the plasma etching,

(ii) means for effecting plasma treatment of the sample after the plasma etching, including supply means for supplying a second plasma-forming gas for the plasma treatment, said second gas being different from said first gas,

(iii) means for contacting the surface of the sample exposed by the plasma etching and the plasma treatment with a liquid adapted to effect at least one of (a) removal of residual corrosive compounds formed in the plasma etching and (b) passivation of said surface, and

(iv) means for drying said sample following contact with said liquid, wherein:

said means for effecting plasma etching comprises a plasma etching chamber; and

said means for effecting plasma treatment comprises a plasma treatment chamber;

said apparatus further comprising:

a loading chamber adjacent said plasma etching chamber;

an unloading chamber adjacent said plasma treatment chamber;

a first rotatable arm for transferring the sample from said loading chamber to said plasma etching chamber; and

a second rotatable arm for transferring the sample from said plasma etching chamber to said plasma treatment chamber and form said plasma treatment chamber to said unloading chamber;

wherein said first rotatable arm and said second rotatable arm are disposed so as o enable the sample to be transferred from said loading chamber to said unloading chamber along a predetermined path;

said apparatus further comprising:

a low pressure enclosure in which said plasma etching chamber, said plasma treatment chamber, said loading chamber, said unloading chamber, said first rotatable arm, and said second rotatable arm are disposed; and

means for maintaining said low pressure enclosure at sub-atmospheric pressure;

wherein said low pressure enclosure comprises a first airlock for enabling the sample to be introduced into said loading chamber and a second airlock for enabling the sample to be removed form said unloading chamber, said loading chamber comprising a sample support table adapted to serve as a door of said first airlock, and sad unloading chamber comprising a sample support table adapted to serve as a door of said second airlock.

12. Apparatus according to claim 11, further comprising:

means for effecting liquid treatment of the sample disposed outside said low pressure enclosure; and

a third rotatable arm for transferring the sample form said second airlock to said means for effecting liquid treatment.

13. Apparatus for processing a sample, comprising

(i) means for effecting plasma etching of he sample, including supply means adapted to supply a first plasma-forming gas for the plasma etching,

(ii) means for effecting plasma treatment of the sample after the plasma etching, including supply means for supplying a second plasma-forming gas for the plasma treatment, said second gas being different from said first gas,

(iii) means for contacting the surface of the sample exposed by the plasma etching and the plasma treatment with a liquid adapted to effect at least one of (a removal of residual corrosive compounds formed in the plasma etching and (b) passivation of said surface, and

(iv) means for drying said sample following contact with said liquid, wherein:

said means for effecting plasma etching comprises a plasma etching chamber having a firs sample table for supporting the sample to be etched by plasma in said plasma etching chamber;

said means for effecting plasma treatment comprises a plasma treatment chamber having a second sample tale for supporting the sample to be treated by plasma in said plasma treatment chamber;

said means for contacting with a liquid comprises a liquid treatment chamber having a third sample table for supporting the sample having the surface to be contacted with a liquid in said liquid treatment chamber; and

said means for drying comprises a drying chamber having a fourth sample table for supporting the sample to be dried in said drying chamber;

said apparatus further comprising:

sample transfer means for transferring the sample from said first sample table to said second sample table, from said second sample table to said third sample table, and from said third sample table to said fourth sample table.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of processing a sample including an etching step, and to an apparatus for carrying out such a method, and more particularly to a processing method and apparatus which is suitable for processing a sample in the manufacture of a semiconductor device or other device including miniaturized components.

2. Description of the Prior Art

A sample such as a semiconductor device substrate is etched by a chemical solution or by plasma, for example. Sufficient care must be paid to corrosion protection of the sample after etching processing.

A corrosion-proofing technique after etching is disclosed, for example, in U.S. Pat. No. 4,487,678. This prior art technique subjects a resist film, after etching by plasma inside an etching chamber, to removal in a second plasma processing chamber connected to the etching chamber. The second plasma treatment removes chlorine compounds which are corrosive components remaining in the resist film or on the etched surface. It is also known to heat the sample after etching to at least 200.degree. C. in order to promote evaporation of chlorides that are residual corrosive components. Japanese Laid-Open Patent Publication No. JP-A-61-133388 discloses a method in which a sample after plasma etching is transferred to a heat-treating chamber in which hot air is blown on it to remove corrosive compounds. Thereafter the sample is washed with water and dried.

The present applicants have found that these prior art techniques involve the problem that sufficient corrosion-proofing performance cannot be obtained, at least for certain kinds of samples.

For instance, the techniques described above are believed effective in some cases for corrosion-proofing of a single metallic film such as an aluminium (Al) wiring film. However, they fail to provide a sufficient corrosion-proofing effect after etching of a sample having metals having mutually different ionization tendencies such as films of Al, Cu, W, Ti, Mo, etc. and their alloys or laminates.

With the remarkable progress in miniaturization in recent years, wiring films have been more and more miniaturized, and an Al-Cu-Si alloy film having a few percent of Cu content in place of the conventional Al-Si alloy film and a laminate structure of the Al-Cu-Si alloy film and a refractory metal film such as titanium tungsten (TiW), titanium nitride (TiN) and molybdenum silicon (MoSi) film for reducing contact resistance have gained wide application as a wiring film in order to prevent breakage due to electromigration and stress migration. In such a wiring film structure, ionization tendencies of Al and Cu, W, Ti, Mo or the like are different so that a kind of battery action develops due to a water component as a medium and corrosion of the wiring film is accelerated by so-called "electrolytic corrosion". Even if corrosive materials generated by etching are removed by utilizing plasma at a high temperature of 200.degree. C. or above, corrosion occurs due to the effect of moisture on remaining corrosive compounds within some minutes or several hours after the sample is withdrawn into the atmosphere.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sample processing method and apparatus which can prevent sufficiently corrosion of a sample after etching irrespective of the kind of sample.

In one aspect, the invention provides a method of processing a sample comprising the steps:

(i) etching the sample by means of an etching plasma, especially an etching plasma formed using a chlorine-containing gas (i.e. a gas containing chlorine gas itself or chlorine compounds),

(ii) after step (i), treating the sample by means of a second plasma to remove residual corrosive compounds formed in step (i), said second plasma being formed in a gas atmosphere different from that of the etching plasma,

(iii) contacting the surface of the sample exposed by steps (i) and (ii) with at least one liquid in order to effect at least one of (a) removal of residual corrosive compounds from step (i) and (b) passivation of said surface exposed by steps (i) and (ii), and

(iv) after step (iii), drying the sample.

As discussed further below, it has surprisingly been found that the combination of steps (ii) and (iii) provides remarkably improved corrosion resistance of a plasma-etched sample.

Where the sample is etched through a mask, the treatment of step (ii) may effect removal of at least part of the mask. The plasma of step (ii) is preferably formed in an oxygen gas atmosphere.

Preferably washing in step (iii) is selected from

(a) washing with water,

(b) washing first with an alkaline liquid and then with water,

(c) washing first with an acidic liquid and then with water, and

(d) washing first with a mixture of nitric acid and hydrofluoric acid and then with water.

Suitably, to avoid contact with air, step (iii) is performed in an inert gas atmosphere. Likewise, step (iv) may be performed in an inert gas atmosphere.

In particular the invention is applicable when a layer which is subjected to the etching of step (i) is (a) a laminate comprising metals of different ionization potentials or (b) an alloy of metals of different ionization potentials. More generally, the etched layer may be selected from films made of Al, Cu, W, Ti, Mo, other refractory metals, alloys thereof (including alloys containing Si), silicides of refractory metals, TiN and TiW and laminates of at least two such films.

In another aspect, the invention provides apparatus for processing a sample, comprising

(i) means for effecting plasma etching of the sample, including supply means adapted to supply a first plasma-forming gas for the plasma etching,

(ii) means for effecting plasma treatment of the sample after the plasma etching, including supply means for supplying a second plasma-forming gas for the plasma treatment, said second gas being different from said first gas,

(iii) means for contacting the surface of the sample exposed by the plasma etching and the plasma treatment with a liquid adapted to effect at least one of (a) removal of residual corrosive compounds formed in the plasma etching and (b) passivation of said surface, and

(iv) means for drying said sample following contact with said liquid.

Preferably the means for plasma etching is a magnetic field-type microwave plasma etching apparatus, and the means for the subsequent plasma treatment is a non-magnetic field-type microwave plasma etching apparatus.

The apparatus may comprise first and second units which are detachable from each other. The first unit includes the plasma etching means and the means for plasma treatment, while the second unit includes the means for contacting with liquid and the drying means. The apparatus further includes means for transfer of a sample from said first unit to said second unit, preferably mounted on said second unit.

Preferably a sample receiving station for receiving a sample to be processed and a sample discharge station for discharging a sample after the processing are on the same side of the apparatus.

In another aspect, the invention provides a sample etching apparatus comprising:

(i) a first plasma chamber for performing plasma etching on the sample,

(ii) means for creating an etching plasma in the first plasma chamber,

(iii) a loading chamber adjacent the first plasma chamber,

(iv) a second plasma chamber for performing plasma treatment of the sample after etching in the first plasma chamber,

(v) means for forming a plasma in the second plasma chamber,

(vi) an unloading chamber adjacent the second plasma chamber,

(vii) a first rotating arm for effecting transfer of the sample from said loading chamber into said first plasma chamber, and

(viii) a second rotating arm for effecting transfer of the sample from the first plasma chamber to the second plasma chamber and from the second plasma chamber to the unloading chamber,

whereby the sample is carried by said rotating arms along a path from said loading chamber to said unloading chamber.

The rotating arms may rotate in a common plane.

In this description, the plasma treatment step after etching is called post-processing, the liquid treatment step is called wet-processing and the drying step is called dry-processing, for convenience.

In the invention, therefore, a sample is etched by use of plasma. After etching, the sample is post-processed by plasma post-processing means by utilizing plasma under a reduced pressure. The post-processed sample from the plasma post-processing means is wet-processed by wet-processing means. The wet-processed sample is dry-processed by dry-processing means. Since post-processing using plasma and wet-processing are both carried out, the corrosive materials that occur due to etching can be removed sufficiently from the etched sample. Therefore, even when the etched sample is withdrawn into external air, for example, its corrosion can be sufficiently prevented irrespective of the kind of sample.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described below by way of non-limitative example with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a sample processing apparatus in accordance with one embodiment of the present invention;

FIG. 2 is a diagrammatic plan view of the apparatus of FIG. 1;

FIG. 3 is a diagrammatic longitudinal side view of the apparatus shown in FIG. 2;

FIGS. 4A-4G illustrate details of structure and operation of one part of the apparatus of FIGS. 2 and 3;

FIGS. 5A and 5B illustrate details of structure and operation of a second part of the apparatus of FIGS. 2 and 3;

FIG. 6 is a sectional view showing an example of a sample;

FIG. 7 is a perspective view showing an example of occurrence of corrosion;

FIG. 8 is a diagram showing the relation between processing modes after etching and the time till occurrence of corrosion; and

FIG. 9 is a block diagram of a sample processing apparatus in accordance with a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, the sample processing apparatus includes a processing apparatus 10 for etching a sample, a plasma post-processing apparatus 20, a wet-processing apparatus 30 and a dry-processing apparatus 40 and is equipped at least with means 50, 60, 70 for transferring the sample between these processing apparatuses.

In FIG. 1, an apparatus for processing, such as etching, the sample by utilizing plasma under a reduced pressure is used as the processing apparatus 10. Examples of the plasma etching apparatuses which may be employed are a plasma etching apparatus, a reactive sputter etching apparatus, a non-magnetic field type microwave plasma etching apparatus, a magnetic field type microwave plasma etching apparatus, an electron cyclotron resonance (ECR) type microwave plasma etching apparatus, a photo-excitation plasma etching apparatus, a neutral particle etching apparatus, and the like. Besides the apparatuses described above, it is possible to employ an apparatus which wet-etches the sample and an apparatus which etches the sample by use of a corrosive gas.

In FIG. 1, the plasma post-processing apparatus 20 post-processes, such as ashes (i.e. removes photoresist by oxidation), the processed sample processed by the processing apparatus 10 by utilizing plasma under a reduced pressure Examples of the ash-processing apparatuses which may be employed are a plasma ashing apparatus, non-magnetic field type and magnetic field type microwave plasma ashing apparatuses, an ECR type microwave plasma ashing apparatus, a photo-excitation plasma ashing apparatus, and the like.

In FIG. 1, the wet-processing apparatus 30, such as a spinning wet processing apparatus, wet-processes the post-processed sample from the plasma post-processing apparatus 20. In the spinning wet-processing apparatus, the post-processed sample is subjected to spinning washing with water, for example, or to spinning washing sequentially with chemical solutions and water. In this case, the chemical solution is selected suitably in accordance with the materials to be removed from the post-processed sample. An inert gas atmosphere such as nitrogen gas or an atmospheric atmosphere is used as the processing atmosphere. Dry-processing such as water removal is sometimes conducted under this state after wet-processing.

In FIG. 1, an apparatus for dry-processing the wet-processed sample from the wet-processing apparatus 30, such as an apparatus for heating and drying the wet-processed sample or an apparatus for blowing a dry gas on the wet-processed sample to dry it, is used as the dry-processing apparatus 40. A nitrogen gas atmosphere or atmospheric atmosphere is used as the processing atmosphere.

In FIG. 1, the sample transfer means 50 has the function of transferring the processed sample between a processing station (not shown) of the processing apparatus 10 and a processing station (not shown) of the plasma post-processing apparatus 20. The sample transfer means 60 has the function of transferring the post-processed sample between a processing station (not shown) of the plasma post-processing apparatus 20 and a processing station (not shown) of the wet-processing apparatus 30. The sample transfer means 70 has the function of transferring the wet-processed sample between a processing station of the wet-processing apparatus 30 and a processing station (not shown) of the dry-processing apparatus 40. The sample transfer means 50 can deliver and receive the sample between the processing station of the processing apparatus 10 and that of the plasma post-processing apparatus 20. The sample transfer means 60 can deliver and receive the sample between the processing station of the plasma post-processing apparatus 20 and that of the wet-processing apparatus 30. The sample transfer means 70 can deliver and receive the sample between the processing station of the wet-processing apparatus 30 and that of the dry-processing apparatus 40. Known transfer means are used as the sample transfer means 50, 60, 70. Examples of such means include an arm conveyor equipped with sample scooping members that pick up and hold the sample which are rotated or reciprocated mechanically, electrically or magnetically, or with sample grippers or sample adsorbers that grip and hold the sample at their outer peripheral edge by electromagnetic adsorption or vacuum adsorption, for example, a belt conveyor having an endless belt spread between a driving roller and a driven roller, an apparatus for transferring the sample by blow force of gas, and the like. If the processing apparatus 10 is the apparatus which processes the sample by utilizing plasma under a reduced pressure, the sample transfer means 50 is disposed in such a manner that the processed sample can be transferred inside a reduced pressure space without being exposed to the external air.

In this case, there are shown disposed in FIG. 1 the sample transfer means 80 which transfers the sample to be processed by the processing apparatus 10 thereto and the sample transfer means 90 for transferring the sample dry-processed by the dry-processing apparatus 40 to a recovery cassette (not shown), for example. Sample transfer means analogous to the sample transfer means 50, 60 are used as these sample transfer means 80 and 90.

If the processing apparatus 10 in FIG. 1 processes the sample by utilizing plasma under a reduced pressure, for example, the sample processing atmosphere of the processing apparatus 10 can be put in communication with, and cut off from, the space in which the sample to be processed by the processing apparatus 10 is transferred thereto and the space in which the processed sample is transferred. The sample processing atmosphere of the plasma post-processing apparatus 20, the space in which the processed sample is transferred and the space in which the post-processed sample is transferred can be put in communication with, and cut off from, one another. The space in which the post-processed sample is transferred, the sample wet-processing atmosphere of the wet-processing apparatus 30, the space in which the wet-processed sample is transferred, the sample dry-processing atmosphere of the dry-processing apparatus 40 and the space in which dry-processed sample is transferred may be maintained in communication with one another or may be put in communication with, and cut off from, one another.

In FIG. 1, the processing station is disposed in the sample processing atmosphere of the processing apparatus 10. If the sample processing apparatus 10 processes the sample by utilizing plasma under a reduced pressure, the processing station is a sample table (not shown). The sample table (not shown) is disposed as the processing station in each of the processing atmosphere of the plasma post-processing apparatus 20, the wet-processing apparatus 30 and the dry-processing apparatus 40. One or a plurality of samples can be put on each sample table. In the processing apparatus 10 and in the plasma post-processing apparatus 20, each sample table is sometimes used as one of the constituent elements forming the sample processing atmosphere

An embodiment of the present invention will be explained in further detail with reference to FIGS. 2 and 3.

In FIGS. 2 and 3, an apparatus for processing the sample by utilizing plasma under a reduced pressure is used as the processing apparatus in this case.

In FIGS. 2 and 3, four openings 101a, 101b, 101c and 101d are formed in the top wall of a buffer chamber 100. An exhaust nozzle 102a is disposed on the bottom wall of the buffer chamber 100. One of the ends of an exhaust pipe (not shown) is connected to the exhaust nozzle 102a and its other end, to a suction port of an evacuation apparatus (not shown) such as a vacuum pump. The planar shape of the buffer chamber 100 is substantially L-shaped. The buffer chamber 100 is made of a stainless steel in this case. When the buffer chamber 100 is viewed on a plan view, the openings 101a, 101b, 101c are formed from the major side to minor side of the L shape and the opening 101d is formed on the minor side of the L shape. The openings 101a-101d have predetermined gaps between the adjacent pairs of them. An arm 81 is disposed rotatably inside the buffer chamber 100. The arm 81 can rotate in one plane in the buffer chamber 100. A sample scooping member 82 is disposed at the rotating end of the arm 81. The sample scooping member 82 has shaped elements opposed in a plane. The orbit of rotation substantially at the center of the sample scooping member 82 is positioned in such a manner as to substantially correspond to the center of each opening 101a, 101b. In other words, the support point of rotation of the arm 81 is positioned so that almost the center of the sample scooping member 82 describes the orbit of rotation described above. The support point of rotation of the arm 81 is positioned at the upper end of a rotary shaft 83 whose upper end projects at that position into the buffer chamber 100, whose lower end projects outside the buffer chamber 100 and which is disposed rotatably on the bottom wall of the buffer chamber 100 while keeping air-tightness. The lower end of the rotary shaft 83 is connected to rotation driving means (not shown) which is disposed outside the buffer chamber 100 in such a manner as to correspond to the bottom wall of the buffer chamber 100. An arm 51 is disposed rotatably inside the buffer chamber 100 at a position different from that of the arm 81 and on the opposite side of the sample path. The arm 51 can rotate in the same plane in the buffer chamber 100 as the arm 81. A sample scooping member 52 is disposed at the rotating end of the arm 51. The planar shape of the sample scooping member 52 is substantially the same as that of the sample scooping member 82. The arm 51 is disposed in such a manner that the orbit of rotation at the center of the sample scooping member 52 corresponds substantially to the center of each opening 101b, 101c, 101d. In other words, the support point of rotation of the arm 51 is positioned at such a position where almost the center of the sample scooping member 52 describes the orbit of rotation described above. The support point of rotation of the arm 51 is positioned at the upper end of a rotary shaft 53 which is disposed rotatably on the bottom wall of the buffer chamber 100 while keeping air-tightness inside the buffer chamber 100 with its upper end projecting at that position into the buffer chamber 100 and with its lower end projecting outside the buffer chamber 100. The lower end of the rotary shaft 53 is connected to a driving shaft of rotation driving means disposed outside the buffer chamber 100 so as to correspond to the bottom wall of the buffer chamber 100, such as a driving shaft of a motor 54.

In FIG. 3, a sample table 110 and a cover member 111 are disposed in such a manner as to interpose the opening 101a between them. The sample table 110 has a sample disposition surface on its surface The planar shape and size of the sample table 100 are such that they can close the opening 101a. The sample table 110 is disposed inside the buffer chamber 100 in such a manner as to be capable of opening and closing the opening 101a and in this case, capable of moving up and down.

An elevation shaft 112 has its axis at the center of the opening 101a with its upper end projecting into the buffer chamber 100 and with its lower end projecting outside the same and is disposed on the bottom wall of the buffer chamber 100 in such a manner that it can move up and down while keeping air-tightness inside the buffer chamber 100. The sample table 110 is disposed substantially horizontally at the upper end of the elevation shaft 112 with its sample disposition surface being the upper surface. The lower end of the elevation shaft 112 is connected to elevation driving means, such as a cylinder rod of a cylinder 113, which is disposed outside the buffer chamber 100 in such a manner as to correspond to the bottom wall of the latter. A seal ring (not shown) is disposed around the outer periphery of the upper surface of the sample table 110 or the inner surface of the top wall of the buffer chamber 100 opposed to the former, that is, on the inner surface of the top wall of the buffer chamber 100 around the opening 101a.

A sample delivery member (not shown) is disposed on the sample table 110. The sample delivery member is disposed in such a manner as to be capable of moving up and down between a position lower than the sample disposition surface of the sample table 110 and a position which projects outward from the opening 101a when the opening 101a is closed by the sample table 110. The planar shape and size of the cover member 111 are such that they can close the opening 101a. The cover member 111 is disposed outside the buffer chamber 100 in such a manner as to be capable of opening and closing the opening 101a and in this case, capable of moving up and down. In this case, an elevation shaft 114 is disposed outside the buffer chamber 100 in such a manner as to be capable of moving up and down with its axis being substantially in conformity with that of the elevation shaft 112. The cover member 111 is disposed substantially horizontally at the lower end of the elevation shaft 114. The upper end of the elevation shaft 114 is connected to elevation driving means, such as a cylinder rod of a cylinder 115, which is disposed above the cover member 111 outside the buffer chamber 100.

A seal ring (not shown) is disposed around the outer periphery of the lower surface of the cover member 111 or the outer surface of the top wall of the buffer chamber 100 opposed to the former, or in other words, around the outer surface of the top wall of the buffer chamber 100 around the opening 101a. The sample table 110 and the cover member 111 are thus doors of an entry airlock of the buffer chamber 100.

A discharge tube 11, whose shape is substantially semi-spherical in this case, is shown disposed hermetically on the top wall of the buffer chamber 100 in FIG. 3. The shape and size of the opening of the discharge tube 11 are substantially the same as those of the opening 101b, and the opening of the discharge tube 11 is substantially in agreement with the opening 101b. The discharge tube 11 is made of an electric insulator such as quartz. A waveguide 12a is disposed outside the discharge tube 11 to surround it. A magnetron 13 as microwave oscillation means and the waveguide 12a are connected by a waveguide 12b. The waveguides 12a and 12b are made of an electric conductor. The waveguide 12b has an isolator 12c and a power monitor 12d. A solenoid coil 14 as magnetic field generation means is disposed outside and around the waveguide 12b.

A sample table 15 is disposed movably up and down inside the space defined inside the buffer chamber 100 and the discharge tube 11. The axis of an elevation shaft 16 is substantially in agreement with the axis of the discharge tube 11 in this case. Tee elevation shaft 16 is disposed on the bottom wall of the buffer chamber 100 movably up and down with its upper end projecting into the buffer chamber 100 and with its lower end projecting outside the buffer chamber 100 while keeping air-tightness inside the buffer chamber 100.

More details of this part of the apparatus are given in FIGS. 5A and 5B, to which reference should be made also.

The sample table 15 has a sample disposition surface on its surface. The planar shape and size of the sample table 15 are such that the sample table 15 can penetrate through the opening 101b. The sample table 15 is disposed substantially horizontally at the upper end of the elevation shaft 16 with its sample disposition surface being its upper surface. The lower end of the elevation shaft 16 is connected to elevation driving means, such as a cylinder rod of a cylinder (not shown), which is disposed outside the buffer chamber 100 in such a manner as to correspond to the bottom wall of the same. In this case, the lower end portion of the elevation shaft 16 is connected to a bias power source, for example, a radio frequency power source 18. The radio frequency power source 18 is disposed outside the buffer chamber 100 and is grounded. In this case, the sample table 15 and the elevation shaft 16 are in an electrically connected state but the buffer chamber 100 and the elevation shaft 16 are electrically isolated.

A sample delivery member 15a (FIG. 5A) is disposed on the sample table 15. The sample delivery member 15a is disposed at a position below the sample disposition surface of the sample table 15 and in such a manner as to be capable of moving up and down with respect to the sample scooping members 82, 52 when the sample disposition surface of the sample table 15 is moved down below the sample scooping member 82 of the arm 81 and the sample scooping member 52 of the arm 51.

The sample table 15 has means for control of temperature. A heat medium flow path is defined inside the sample table 15, for example, and a cooling medium as a heat medium such as cooling water, liquid ammonia, liquid nitrogen, or the like, or a heating medium such as heating gas is supplied to the flow path. Heat generation means such as a heater, for example, is disposed on the sample table 15.

Flanges 120 and 121 are disposed around the sample table 15 and the elevation shaft 16 inside the buffer chamber 100. The inner diameter and shape of each flange 120, 121 are substantially in conformity with those of the opening 101b. The flange 120 is disposed air-tight on the inner surface of the bottom wall of the buffer chamber 100 with the axis of the elevation shaft 16 being substantially at its center. The flange 121 is disposed in such a manner as to oppose the flange 120. Metallic bellows 122 as extension-contraction cut means are disposed in such a manner as to bridge these flanges 120 and 121.

An elevation shaft 122a is disposed movably up and down with its upper end projecting into the buffer chamber 100 and with its lower end projecting outside the buffer chamber 100 while keeping air-tightness inside the buffer chamber 100. The flange 121 is connected to the upper end of the elevation shaft. The lower end of the elevation shaft is connected to elevation driving means such as a cylinder rod of a cylinder (not shown) disposed outside the buffer chamber 100 in such a manner as to correspond to the bottom wall of the buffer chamber 100.

A seal ring is disposed on the upper surface of the flange 121 or the inner surface of the top wall of the buffer chamber 100 opposing the former, or in other words, on the inner surface of the top wall of the buffer chamber 100 around the opening 101b.

An exhaust nozzle 102b is disposed on the bottom wall of the buffer chamber 100 more inward- than the flange 120. One of the ends of an exhaust pipe (not shown) is connected to the exhaust nozzle 102b and its other end, to the suction port of an evacuation apparatus (not shown) such as a vacuum pump. A switch valve (not shown) and a pressure regulating valve such as a variable resistance valve (not shown) are disposed in the exhaust pipe. One of the ends of a gas introduction pipe (not shown) is connected to a processing gas source (not shown) and its other end opens into the discharge tube 11, or the like. A switch valve and a gas flow rate regulator (not shown) are disposed in the gas introduction pipe.

In FIG. 3, the plasma post-processing chamber 21 is hermetically disposed on the top wall of the buffer chamber 100. The shape and size of the opening of the plasma post-processing chamber 21 are substantially in agreement with those of the opening 101c and the opening of the plasma post-processing chamber 21 is substantially in agreement with the opening 101c. A sample table 22 is disposed in the space defined by the interior of the buffer chamber 100 and that of the plasma post-processing chamber 21. A support shaft 23 in this case uses the axis of the plasma post-processing chamber 21 as its axis. It is disposed on the bottom wall of the buffer chamber 100 with its upper end projecting into the buffer chamber 100 and with its lower end projecting outside the buffer chamber 100 while keeping air-tightness inside the buffer chamber 100.

The sample table 22 has a sample disposition surface on its surface. The planar shape and size of the sample table 22 are smaller than those of the opening 101c in this case. The sample table 22 is disposed substantially horizontally at the upper end of the support shaft 23 with its sample disposition surface being the upper surface. The sample disposition surface of the sample table 22 is positioned below the sample scooping member 52 of the arm 51.

A sample delivery member (not shown) is disposed on the sample table 22. In other words, the sample delivery member is disposed movably up and down between a position lower than the sample disposition surface of the sample table 22 and a position higher than the sample scooping member 52 of the arm 51.

Flanges 125 and 126 are disposed outside the sample table 22 and the support shaft 23 but inside the buffer chamber 100. The inner diameter and shape of each flange 125, 126 are substantially in conformity with those of the opening 101c. The flange 125 is disposed hermetically on the inner surface of the bottom wall of the buffer chamber 100 substantially coaxial with the axis of the support shaft 23. The flange 126 opposes the flange 125. Metallic bellows 127 as extension-contraction cut means bridge between these flanges 125 and 126. An elevation shaft (not shown) is disposed movably up and down on the bottom wall of the buffer chamber 100 with its upper end projecting into the buffer chamber 100 and with its lower end projecting outside the buffer chamber 100 while keeping air-tightness inside the buffer chamber 100.

The flange 126 is connected to the upper end of the elevation shaft. The lower end of the elevation shaft is connected to elevation driving means such as a cylinder rod of a cylinder (not shown) which is disposed outside the buffer chamber 100 so as to correspond to the bottom wall of the buffer chamber 100. A seal ring (not shown) is disposed on the upper surface of the flange 126 or the inner surface of the top wall of the buffer chamber 100 opposing the upper surface of the flange 126, or in other words, on the inner surface of the top wall of the buffer chamber 100 around the opening 101c. An exhaust nozzle 102c is disposed on the bottom wall of the buffer chamber 100 which is more inward than the flange 125. One of the ends of an exhaust pipe (not shown) is connected to the exhaust nozzle 102c and its other end, to the suction port of an evacuation apparatus (not shown) such as a vacuum pump.

In FIG. 3, a sample table 130 and a cover member 131 are disposed in such a manner as to interpose the opening 101d between them. This part of the apparatus and its operation are shown in more detail in FIGS. 4A-G, to which reference should be made also. The sample table 130 has a sample disposition surface on its surface. The planar shape and size of the sample table 130 are such that the sample table 130 can sufficiently close the opening 101d. The sample table 130 is disposed movably up and down, in this case, inside the buffer chamber 100 in such a manner as to be capable of opening and closing the opening 101d. In this case, an elevation shaft 132 is disposed movably up and down on the bottom wall of the buffer chamber 100 with its upper end projecting into the buffer chamber 100 and with its lower end projecting outside the buffer chamber 100 while keeping air-tightness inside the buffer chamber 100. The sample table 130 is disposed substantially horizontally at the upper end of the elevation shaft 132 with its sample disposition surface being the upper surface. The lower end of the elevation shaft 132 is connected to elevation driving means such as a cylinder rod of a cylinder 133 which is disposed outside the buffer chamber 100 in such a manner as to correspond to the bottom wall of the buffer chamber 100.

A seal ring is disposed around the outer peripheral edge of the upper surface of the sample table 130 (as shown) or the inside of the top wall of the buffer chamber 100 opposing the outer peripheral edge, that is, on the inner surface of the top wall of the buffer chamber 100 around the opening 101d. A sample delivery member 130a is disposed on the sample table 130. It is disposed movably up and down between a position lower than the sample disposition surface of the sample table 130 and a position projecting outward from the opening 101d under the state where the opening 101d is closed by the sample table 130.

The planar shape and size of a cover member 131 are such that the cover member 131 can open and close the opening 101d. It is disposed movably up and down, in this case, outside the buffer chamber 100. The axis of an elevation shaft 134 is substantially in agreement with that of the elevation shaft 132, in this case. This elevation shaft 134 is disposed movably up and down outside the buffer chamber 100. The cover member 131 is disposed substantially horizontally at the lower end of the elevation shaft 134. The upper end of the elevation shaft 134 is connected to elevation driving means such as a cylinder rod of a cylinder 135 which is disposed at a position above the cover member 131 outside the buffer chamber 100. A seal ring is disposed around the outer peripheral edge of the lower surface of the cover member 131 (as shown) or the outer surface of the top wall of the buffer chamber 100 opposing the former, that is, the outer surface of the top wall of the buffer chamber 100 around the opening 101d. The sample table 130 and the cover member 131 thus constitute doors of an exit airlock for the buffer chamber 100.

A cassette table 140 is disposed movably up and down in such a manner as to correspond to the side surface of the L-shaped major side of the buffer chamber 100 outside the buffer chamber 100. A guide 141 is disposed outside the buffer chamber 100 in such a manner as to extend linearly along the side surface of the L-shaped major side in its transverse direction. The edge of this guide 141 on the side of the cassette table 140 is extended so as to correspond to the center of the cassette table 140, in this case. An arm 142 is a linear member in this case, and one of its ends is disposed on the guide 141 in such a manner as to be capable of reciprocation while being guided by the guide 141. A sample scooping member 143 is disposed at the other end of the arm 142. The cassette table 140 is disposed substantially horizontally at the upper end of an elevation shaft 144 with a cassette disposition surface being its upper surface. The lower end of the elevation shaft 144 is connected to elevation driving means 145.

The wet-processing chamber 31, the dry-processing chamber 41 and a sample recovery chamber 150 are disposed outside the buffer chamber 100, in this case. They form a unit connectable to and disconnectable from the buffer chamber unit. The wet-processing chamber 31, the dry-processing chamber 41 and the sample recovery chamber 150 are aligned sequentially along the side walls on the side of the openings 101c, 101d of the buffer chamber 100 in this case. Among them, the wet-processing chamber 31 is disposed at the position closest to the opening 101d.

A sample table 32 is disposed inside the wet-processing chamber 31. A support shaft 33 is disposed rotatably on the bottom wall of the wet-processing chamber 31 with its upper end projecting into the wet-processing chamber 31 and with its lower end projecting outside the wet-processing chamber 31 in such a manner as to keep air-tightness and water-tightness inside the wet-processing chamber 31 in this case. The lower end of the support shaft 33 is connected to a rotary shaft of a motor (not shown) as rotation driving means, for example.

The sample table 32 has a sample disposition surface on its surface. The sample table 32 is disposed substantially horizontally at the upper end of the support shaft 33 with the sample disposition surface being its upper surface. The sample disposition surface of the sample table 32 is positioned below a sample scooping member 62 of an arm 61.

The sample table 32 is equipped with a sample delivery member (not shown). The sample delivery member is disposed movably up and down between a position below the sample disposition surface of the sample table 32 and a position above the sample scooping member 62 of the arm 61. A processing liquid feed pipe (not shown) is disposed inside the wet-processing chamber 31 in such a manner as to be capable of supplying a processing solution to the sample disposition surface of the sample table 32. A processing solution feed apparatus (not shown) is disposed outside the wet-processing chamber 31. The processing solution feed pipe is connected to this processing solution feed apparatus. A waste liquor discharge pipe (not shown) is connected to the wet-processing chamber 31. In this case, inert gas introduction means (not shown) for introducing an inert gas such as nitrogen gas into the wet-processing chamber 31 are provided.

In FIGS. 2 and 3, the arm 61 is disposed rotatably so as to correspond to the sample tables 130 and 32. The arm 61 can rotate on the same plane outside the buffer chamber 100. The sample scooping member 62 is disposed at the rotating end of the arm 61. The planar shape of the sample scooping member 62 is substantially the same as those of the sample scooping members 52 and 82. The arm 61 is disposed in such a manner that the orbit of rotation of the center of the sample scooping member 62 corresponds substantially to the centers of the sample tables 130 and 32, respectively. In other words, the support point of rotation of the arm 61 is positioned to a position where almost the center of the sample scooping member 62 describes the orbit of rotation described above.

The support point of rotation of the arm 61 is disposed at the upper end of the rotary shaft 63 disposed rotatably outside the buffer chamber 100 and outside the wet-processing chamber 31. The lower end of the rotary shaft 63 is connected to the driving shaft of a motor 64, for example, as rotation driving means. An opening 34 is bored on the side wall of the wet-processing chamber 31 that corresponds to the rotation zones of the arm 61 and sample scooping member 62. The size and position of the opening 34 are such that they do not prevent the entry and exit operations of the arm 61 and sample scooping member 62 with respect to the wet-processing chamber 31. The opening 34 can be opened and closed by switch means (not shown) in this case.

A sample table 42 is disposed inside the dry-processing chamber 41. The sample table 42 has a sample disposition surface on its surface. It is disposed substantially horizontally on the bottom wall of the dry-processing chamber 41. A heater 43 is used as heating means in this case. The heater 43 is disposed on the back of the sample table 42 in such a manner as to be capable of heating the sample table 42. It is connected to a power source (not shown).

The sample disposition surface of the sample table 42 is positioned below a sample scooping member 72 of an arm 71. A sample delivery member (not shown) is disposed on the sample table 42. In other words, the sample delivery member is disposed movably up and down between a position below the sample disposition surface of the sample table 42 and a position above the sample scooping member 72 of the arm 71. In this case, the sample delivery member, too, is capable of moving up and down between a position below the sample disposition surface of the sample table 32 and a position above the sample scooping member 72 of the arm 71. In this case, there is provided inert gas introduction means (not shown) for introducing an inert gas such as nitrogen gas into the dry-processing chamber 41.

A cassette table 151 is disposed inside a sample recovery chamber 150. An elevation shaft 152 is disposed movably up and down on the bottom wall of the sample recovery chamber 150 with its upper end projecting into the sample recovery chamber and with its lower end projecting outside the sample recovery chamber 150. The cassette table 151 is disposed substantially horizontally at the upper end of the elevation shaft 152 with a cassette disposition surface being its upper surface. The lower end of the elevation shaft 152 is disposed on elevation driving means 153. In this case, inert gas introduction means (not shown) are arranged so as to introduce an inert gas such as nitrogen gas into the sample recovery chamber 150.

In FIG. 2, a guide 73 is disposed along the inner wall surface of each of the wet-processing chamber 31, the dry-processing chamber 41 and the sample recovery chamber 150. The guide 73 has a linear shape. In other words, the line passing through the centers of the sample tables 32, 42 and the cassette table 151 is a straight line and the guide 73 is disposed substantially parallel to this line. The arm 71 is a linear member in this case and one of its ends is disposed on the guide 73 so as to be capable of reciprocation while being guided by the guide 73. A sample scooping member 72 is disposed at the other end of the arm 71.

Openings (not shown) are formed on the side walls of the wet- and dry-processing chambers 31, 41 and the sample recovery chamber 150 corresponding to the reciprocation zones of the arm 71 and the sample scooping member 72, respectively, so that the arm 71 and the sample scooping member 72 are no prevented from coming into and out form the wet-processing chamber 31, the dry-processing chamber 41 and the sample recovery chamber 150, respectively. These openings can be opened and closed by switch mean (not shown), respectively. An opening for loading and discharging a cassette and a door (not shown) are disposed in the sample recovery chamber 150.

A cassette 160 is disposed on a cassette table 140. It can store a plurality of samples 170 one by one stacked in the longitudinal direction, and one of its side surfaces is open in order to take out the samples 170 form the cassette 160. The cassette 160 is disposed on the cassette table 140 with its sample take-outside surface facing the opening 101a. The cassette table 140 supporting the cassette 160 thereon is moved down, for example, under this state. Descent of the cassette table 140 is stopped at the position where the sample 170 stored at the upper most stage of the cassette 160 can be scooped up by the sample scooping member 143.

The operation of this apparatus is as follows:

The openings 101a and 101d are closed by the sample tables 110 and 130, respectively, and when an evacuation apparatus is operated under this state, the inside of the buffer chamber 100 is evacuated to a predetermined pressure. Thereafter, the cover member 111 is moved up and this ascent is stopped at the position where the sample scooping member 143 for scooping up the sample 170 is not prevented from reaching the opening 101a. The arm 142 is moved towards the cassette 160 under this state and this movement is stopped at the position where the sample scooping member 143 corresponds to the back of the sample 170 stored at the lowermost stage of the cassette 160, for example. Thereafter the cassette 160 is moved up by the distance at which the sample scooping member 143 can scoop up the sample 170. In this manner the sample 170 is scooped up on its back by the sample scooping member 143 and delivered to the sample scooping member 143.

When the sample scooping member 143 receives the sample 170, the arm 142 is moved towards the opening 101a. This movement of the arm 142 is stopped at the point where the sample scooping member 143 having the sample 170 reaches the position corresponding to the opening 101a. Under this state the sample delivery member of the sample table 110 is moved up so that the sample 170 is delivered from the sample scooping member 143 to the sample delivery member. Thereafter, the sample scooping member 143 is retreated to the position at which it does not prevent descent of the sample delivery member receiving the sample 170, by the movement of the arm 142.

Thereafter the sample delivery member having the sample 170 is moved down and the sample 170 is delivered from the sample delivery member to the sample table 110 and placed on its sample disposition surface. Then, the cover member 111 is moved down. Accordingly, the opening 101a is closed by the cover member 111 and its communication with the outside is cut off. Thereafter, the sample table 110 having the sample 170 is moved down and this downward movement is stopped at the point where the sample table 110 reaches the position at which the sample 170 can be exchanged between the sample delivery member of the sample table 110 and the sample scooping member 82 of the arm 81.

The flange 121 and the metallic bellows 122 are moved down by the shaft 122a lest they prevent the rotation of the arm 81 and the sample scooping member 82 and the sample table 15 is moved down to the position where its sample delivery member 15a and the sample scooping member 82 of the arm 81 can exchange the sample 170 between them. Under this state the sample delivery member 15a is moved up so that it can exchange the sample 170 with the sample scooping member 82 of the arm 81. The arm 81 is then rotated in the direction of the sample table 110 and the sample scooping member 82 is located at the position which corresponds to the back of the sample 170 held by the sample delivery member of the sample table 110 and at which it can scoop up the sample 170. Under this state the sample delivery member of the sample table 110 is moved down and the sample 170 is delivered to the sample scooping member 82 of the arm 81. After scooping up the sample 170, the sample scooping member 82 is rotated in the direction of the sample table 15 while passing between the flange 121 and the inner surface of the top wall of the buffer chamber 100 as the arm 81 is rotated in the direction of the sample table 15.

The sample table 110 is moved up once again so that the opening 101a is closed by the sample table 110. The rotation of the sample scooping member 82 described above is stopped when the sample scooping member 82 reaches the position where the sample 170 ca be exchanged between the sample scooping member 82 and the sample delivery member 15a of the sample table 15. The sample delivery member 15a of the sample table 15 is moved up under this stage so that the sample 170 is delivered from the sample scooping member 82 to the sample delivery member 15a of the sample table 15. Thereafter, when the arm 81 is rotated to the position between the openings 101a and 101b the sample scooping member 82 is brought into the stand-by state to prepare for the next delivery of the sample between the sample tables 110 and 15.

Thereafter the flange 121 and the metallic bellows 122 are moved up by the shaft 122a so that communication of the buffer chamber 100 in the metallic bellows 122 and the inside of the discharge tube 11 with the interior of the buffer chamber 100 outside the metallic bellows 122 is cut off. When the sample delivery member 15a of the sample table 15 receiving the sample 170 is moved down, the sample 170 is delivered from the sample delivery member 15a of the sample table 15 to the sample table 15 and is placed on the sample disposition surface of the sample table 15. After receiving the sample 170 on its sample disposition surface, the sample table 15 is moved up to a predetermined position (see FIG. 5A) inside the space where communication with the buffer chamber 100 outside the metallic bellows 122 is cut off.

A predetermined processing gas is introduced at a predetermined flow rate from the processing gas source into the space in which communication with the buffer chamber 100 outside the metallic bellows 122 is cut off. Part of the processing gas introduced into this space is exhausted outside the space due to the operations of the evacuation apparatus and the variable resistance valve. In this manner the pressure of this space is controlled to a predetermined pressure for etching treatment.

The magnetron 13 oscillates a 2.45 GHz microwave in this case. The microwave thus oscillated propagates through the waveguides 12b and 12a through the isolator 12c and the power monitor 12d and are absorbed by the discharge tube 11, thereby generating a radio frequency field containing the microwave. At the same time, the solenoid coil 14 is operated to generate a magnetic field. The processing gas existing inside the space where communication with the buffer chamber 100 outside the metallic bellows 122 is cut off is converted to plasma due to the synergistic operations of the radio frequency field containing the microwave and the magnetic field. The sample 170 disposed on the sample table 15 is etched by utilizing this plasma.

Thereafter the sample table 15 and the flange 121 are moved downwardly (FIG. 5B) and the sample delivery member 15a is moved upwardly.

The rotation of the sample scooping member 52 is stopped at the point when the sample scooping member 52 reaches the position where the etched sample 170 can be exchanged between the sample scooping member 52 and the sample delivery member 15a of the sample table 15. The sample delivery member 15a of the sample table 15 is moved down under this state and the etched sample 170 is delivered from the sample delivery member 15a of the sample table 15 to the sample scooping member 52 of the arm 51. After scooping up the etched sample 170, the sample scooping member 52 is rotated in the direction of the sample table 22 while passing between the flange 121 and the inner surface of the top wall of the buffer chamber 100 as the arm 51 is rotated in the direction of the sample table 22.

A new sample in the cassette 160 is placed by the operations described above on the sample table 15 from which the etched sample 170 is removed. The new sample placed on the sample table 15 is subsequently etch-processed due to the operations described above.

Before, or during, the rotation of the sample scooping member 52 having the etched sample 170, the flange 126 and the metallic bellows 127 are moved down lest they prevent the rotation of the arm 51 and the sample scooping member 52. The radio frequency power source 18 is operated at the time of etching of the sample 170, a predetermined radio frequency power is applied to the sample table 15 through the elevation shaft 16 and a predetermined radio frequency bias is applied to the sample 170. The sample 170 is adjusted to a predetermined temperature through the sample table 15.

The operations of the magnetron 13, solenoid coil 14 and radio frequency power source 18, and the like, are stopped at the point where etching of the sample 170 is complete and introduction of the processing gas into the space whose communication with the inside of the buffer chamber 100 outside the metallic bellows 122 is cut off is stopped. After evacuation of this space is conducted sufficiently, the switch valve constituting the evacuation means is closed. Thereafter, the flange 121 and the metallic bellows 122 are moved down so as not to prevent the rotation of the arm 51 and the sample scooping member 52 and the sample table 15 is moved down to the position where its sample delivery member and the sample scooping member 52 of the arm 51 can exchange the etched sample 170. The sample delivery member of the sample table 15 is then moved up so that it can exchange the etched sample 170 with the sample scooping member 52 of the arm 51. When the arm 51 is rotated under this state in the direction of the sample table 15, the sample scooping member 52 passes between the flange 121 and the inner surface of the top wall of the buffer chamber 100 and is rotated in the direction of the sample table 15.

The sample scooping member 52 having the etched sample 170 is rotated in the direction of the sample table 22 while passing between the flange 126 and the inner surface of the top wall of the buffer chamber 100 when the arm 51 is rotated further in the direction of the sample table 22. Such a rotation of the sample scooping member 52 is stopped when the sample scooping member 52 reaches the position where the etched sample 170 can be exchanged between the sample scooping member 52 and the sample delivery member of the sample table 22. The sample delivery member of the sample table 22 is moved up under this state and the etched sample 170 is delivered from the sample scooping member 52 to the sample delivery member of the sample table 22. Thereafter the sample scooping member 52 is rotated to the position between the openings 101c and 101d and is brought into the stand-by state.

Thereafter, the flange 126 and the metallic bellows 127 are moved up and the interior of the buffer chamber 100 inside the metallic bellows 127 and the interior of the plasma post-processing chamber 21 are cut off from communication with the interior of the buffer chamber 100 outside the metallic bellow 127. When the sample delivery member of the sample table 22 receiving the etched sample 170 is moved down, the etched sample 170 is delivered from the sample delivery member of the sample table 22 to the sample table 22 and is placed on the sample disposition surface of the sample table 22.

The post-processing gas is introduced at a predetermined flow rate into the space whose communication with the interior of the buffer chamber 100 outside the metallic bellows 127 is cut off, and part of the post-processing gas is exhausted from this space. In this manner the pressure of this space is adjusted to a predetermined post-processing pressure. Thereafter, the post-processing gas existing in this space is converted in this case to plasma due to the operation o