JPH09306896A - Plasma processor and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to etch without generating etching shape differences at the center and peripheral edge of a wafer by improving an electric field correction at the edge of the wafer. SOLUTION: The plasma processor 10 has a first electrode 11, a second electrode 12 opposed to the electrode 11 to place a wafer 19, and comprises a conductive first annular part 13 protruding on the electrode 12 side and provided on the outer periphery of the surface of the electrode 11 opposed to the electrode 12, and a conductive second annular part 14 provided on the outer periphery of the electrode 12. The wafer is plasma processed by satisfying predetermined conditions at the inner diameter Din and outer diameter Dout of the part 13, protruding amount Hout from the electrode surface, and the size Dsi of the wafer 19 and the distance L between the electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a plasma processing method, and more particularly to a plasma processing apparatus and a plasma processing method used for etching a semiconductor wafer.

[0002]

2. Description of the Related Art A plasma processing apparatus in which a gas and a high frequency are introduced into a vacuum chamber to generate plasma, and the surface of a semiconductor wafer is subjected to processing such as etching and ashing by the plasma is indispensable in manufacturing highly integrated semiconductor devices. It cannot be done.

Among these plasma processing apparatuses, there is an apparatus called a parallel plate type etching apparatus. In this apparatus, a wafer is placed on either one of two electrodes facing each other inside a reaction vessel, and high-frequency power is supplied while introducing a processing gas between the two electrodes to generate plasma. The wafer is processed.

However, the parallel plate type plasma processing apparatus is
For example, when etching, the etching rate of the wafer peripheral portion tends to be smaller than that of the wafer central portion,
This non-uniform etching rate distribution on the wafer surface has been a problem.

To solve this problem, Japanese Patent Laid-Open No. 5-29
Japanese Patent No. 275 discloses a device in which an annular portion is provided on one electrode surface.

FIG. 6 is a schematic sectional view showing a plasma processing apparatus provided with this annular portion. A first electrode 31 and a second electrode 32 facing the first electrode 31 are arranged in the reaction container 15, and the wafer 19 is placed on the second electrode 32. The first electrode 31 is fixed to the inner wall surface of the reaction container 15 via an insulator 38a, and the second electrode 32 is fixed to the inner wall surface of the reaction container 15 via an insulator 38b.
The first electrode 31 and the second electrode 32 are connected to AC power supplies 31a and 31b, respectively. Then, the annular portion 33 is formed on the surface of the first electrode 31, and the wafer peripheral portion 19b is formed.
The electrode interval of the wafer central portion 19a is widened.

In this plasma processing apparatus 30, since the electrode interval of the wafer peripheral portion 19b is narrow and the electrode interval of the wafer central portion 19a is wide, the electric field between the wafer central portion 19a and the wafer peripheral portion 19b is larger than that of the conventional apparatus. The balance of strength can be improved. As a result, the uniformity of the etching rate within the surface of the wafer 19 can be improved.

[0008]

However, the plasma processing apparatus having the above-described annular portion is simply provided with the annular portion on one electrode surface, and the electrode interval at the wafer peripheral portion is narrow and the electrode interval at the wafer central portion is wide. Therefore, the electric field correction at the peripheral portion of the wafer is not sufficient, and the shapes of holes and grooves (hereinafter referred to as etching shapes) formed by etching are different between the peripheral portion of the wafer and the central portion of the wafer. There was a problem that it would end up.

In particular, in an apparatus including the second electrode having an electrostatic chuck structure in which the electrode body is covered with an insulating film, the problem of this etching shape difference is large.

The present invention has been made to solve the above-mentioned problems, and improves the electric field correction at the peripheral portion of the wafer, and performs etching so as not to cause a difference in shape between the central portion of the wafer and the peripheral portion of the wafer. An object of the present invention is to provide a plasma processing apparatus and a plasma processing method capable of performing the above.

[0011]

To achieve the above object, a plasma processing apparatus of the present invention is a plasma processing apparatus including a first electrode and a second electrode on which a wafer facing the first electrode is mounted. A conductive first annular portion protruding toward the second electrode is provided on an outer peripheral portion of a surface of the first electrode facing the second electrode, and a conductive second annular portion is provided on an outer peripheral portion of the second electrode.
It is characterized in that an annular portion is provided.

The plasma processing apparatus of the present invention is suitable for an apparatus in which the second electrode has an electrostatic chuck structure.

The plasma processing method of the present invention is a plasma processing method using the above plasma processing apparatus, wherein the inner diameter Din (mm) and the outer diameter Dout (m) of the first annular portion are provided.
m) and the amount of protrusion of the first electrode from the electrode surface Hout (m
m) is the wafer size DSi (mm) of the wafer to be processed
And a wafer placed on the second electrode under the condition that the following formulas (1), (2), and (3) are satisfied with respect to the distance L (mm) between the first electrode and the second electrode. A plasma processing method, characterized in that the plasma processing is performed on the.

1.03 × DSi ≦ Din ≦ 1.09 × DSi (1) 1.10 × DSi ≦ Dout ≦ 1.20 × DSi (2) 0.7 × L-2.0 ≦ Hout ≦ 0.7 × L + 2.0 (3) The plasma processing apparatus of the present invention includes the conductive first annular portion on the outer peripheral portion of the first electrode so as to project from the electrode surface.
Therefore, since the first electrode apparently approaches the second electrode,
The reduction of the electric field strength at the peripheral portion of the wafer can be suppressed.

A conductive second annular portion is provided on the outer peripheral portion of the second electrode. Therefore, the second electrode is apparently large, so that the lines of electric force are formed even in the peripheral portion of the wafer and are perpendicular to the wafer.

As a result, the electric field correction at the peripheral portion of the wafer is improved, and a uniform electric field is obtained over the entire surface of the wafer. Therefore, not only the etching rate is made equal between the central portion of the wafer and the peripheral portion of the wafer, but also a difference in etching shape is caused. It can be etched to prevent it.

Silicon is preferably used for the first and second annular portions. This is because silicon is a material that is less likely to contaminate the wafer with impurities or the like.
In addition, in order to increase the conductivity of silicon used for the first and second annular portions, boron (B) or the like may be doped.

The size of the second electrode having an electrostatic chuck structure in which the wafer mounting surface of the electrode body is covered with an insulating film is limited by the size of the wafer. That is, in order to prevent the insulating film covering the electrode body from being destroyed by plasma irradiation, the wafer mounting surface of the second electrode should be covered so that the insulating film of the second electrode is completely covered by the mounted wafer. Is smaller than the wafer. Therefore, it is usually difficult to make the lines of electric force vertical at the peripheral portion of the wafer.

The plasma processing apparatus of the present invention is provided with the second annular portion on the outer peripheral portion of the second electrode so that the second electrode is apparently enlarged. Therefore, while keeping the restriction on the size of the second electrode due to the electrostatic chuck structure,
Electric lines of force can be formed uniformly at the peripheral portion of the wafer and perpendicular to the wafer. As a result, it is possible to improve the electric field correction at the peripheral portion of the wafer and perform etching so as not to cause a difference in shape between the central portion of the wafer and the peripheral portion of the wafer.

Further, the plasma processing method of the present invention is a plasma processing method using the above plasma processing apparatus, wherein the inner diameter Din, the outer diameter Dout and the protrusion amount Hout from the electrode surface of the first annular portion are With respect to the size DSi and the distance L between the first electrode and the second electrode, the above (1),
Plasma processing is performed on the wafer mounted on the second electrode under the condition that the expressions (2) and (3) are satisfied. For example, if the wafer is subjected to an etching process under this condition, the etching rate does not decrease so much and etching can be performed without causing a difference in shape between the wafer central portion and the wafer peripheral portion.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a plasma processing apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing a plasma processing apparatus of the present invention.

The reaction container 15 is composed of an airtight container, and can be brought to a required reduced pressure state by exhausting with an exhaust device (not shown). A turbo molecular pump, a rotary pump, or the like is used as the exhaust device.

The first electrode 11 is provided on the reaction vessel 15. As the material of the first electrode 11, polycrystalline silicon, single crystal silicon, aluminum, carbon or the like is used. Above all, it is preferable to use polycrystalline silicon or single crystal silicon which causes less wafer contamination. First
The electrode 11 is a seal plate 17 made of aluminum or the like.
The electrode pressing ring 23 is pressed and fixed on the top. The seal plate 17 and the device inner wall surface 10a are insulated by an insulator 18.

A gas introduction passage 16 is formed in the center of the seal plate 17, and the gas introduction passage 16 is connected to a gas supply source (not shown). In addition, gas is supplied into the reaction vessel 15 through a gas introduction hole 11a formed in the first electrode 11.

A second electrode 12 is arranged below the reaction vessel 15 so as to face the first electrode 11. Second electrode 12
A wafer 19 is placed on the upper surface of the. The second electrode 12 in this example has an electrostatic chuck structure, and has a structure in which the wafer mounting surface of the electrode body 12b made of aluminum or the like is covered with an insulating film 12a such as alumina. Further, the outer surface of the second electrode 12 and the inner wall surface 10a of the device
Are insulated from each other by an insulator 18.

A second electrode is formed on the outer peripheral portion of the electrode surface of the first electrode 11.
A first annular portion 13 protruding toward the electrode 12 side is provided. The first electrode 11 and the first annular portion 13 are mechanically and electrically joined by being screwed to the electrode pressing ring 23.

As the material of the first annular portion 13, polycrystalline silicon, single crystal silicon, aluminum, carbon or the like can be used. It is preferable to use polycrystalline silicon or single crystal silicon which is less likely to contaminate the wafer with impurities. Note that boron (B) or the like may be doped to increase the conductivity of polycrystalline silicon or single crystal silicon.

The inner diameter Din (mm), the outer diameter Dout (mm) of the first annular portion 13, and the protrusion amount Hout of the first electrode from the electrode surface.
(Mm), wafer size to be processed DSi (mm)
And it is preferable to set the following range with respect to the inter-electrode distance L (mm) between the first electrode 11 and the second electrode 12.

1.03 × DSi ≦ Din ≦ 1.09 × DSi (1) 1.10 × DSi ≦ Dout ≦ 1.20 × DSi (2) 0.7 × L-2.0 ≦ Hout ≦ 0.7 × L + 2.0 (3) For example, the wafer size DSi is 150 mm, the distance L between the electrodes is
Is 15 mm, the preferable range of the inner diameter Din, the outer diameter Dout, and the protrusion amount Hout from the electrode surface is as follows.

154.5 ≦ Din ≦ 163.5 (1 ′) 165.0 ≦ Dout ≦ 180.0 (2 ′) 8.5 ≦ Hout ≦ 12.5 (3 ′) The reason why the preferable range of the inner diameter Din of the first annular portion 13 is set to the above range is that when the inner diameter Din is in the above range, a good etching shape can be obtained even in the peripheral portion of the wafer as described later. .

The reason for setting the outer diameter Dout within the above range is that when the outer diameter Dout is larger than the lower limit value, it is possible to sufficiently correct the electric field strength up to the peripheral portion of the wafer, and when it is larger than the upper limit value, This is because the average electric field strength on the electrode surface of the first electrode is lowered and the etching rate is lowered.

The reason why the protrusion amount Hout from the electrode surface is set in the above range is that a good etching shape can be obtained even in the peripheral portion of the wafer in this range.

A second annular portion 14 made of silicon is disposed on the outer peripheral portion of the second electrode 12. The surfaces of the second annular portion 14 and the second electrode 12 on the side facing the first electrode 11 have substantially the same height and are flat. In addition, the second annular portion 14 is
It is in a floating state (not electrically grounded) and is connected to the second electrode 12 in high frequency.

As the material of the second annular portion 14, as with the first annular portion 13, polycrystalline silicon, single crystal silicon, aluminum, carbon or the like can be used. Above all, it is preferable to use polycrystalline silicon or single crystal silicon, which is less likely to contaminate the wafer with impurities. Note that boron (B) or the like may be doped to increase the conductivity of polycrystalline silicon or single crystal silicon.

The inner diameter of the second annular portion 14 is, of course, larger than the outer diameter of the second electrode 12, but is preferably as small as possible. The reason is that the lines of electric force at the peripheral portion of the wafer are made vertical. This is also for preventing the discharge from occurring in the gap between the second electrode 12 and the second annular portion 14 and preventing the insulating film 12a of the second electrode 12 from being destroyed by this discharge.

The outer diameter of the second annular portion 14 is
It is preferable to make it 8 mm or more larger than the inner diameter. This is to sufficiently correct the electric field at the peripheral portion of the wafer. The outer diameter of the second annular portion 14 is preferably the same as or smaller than the outer diameter Dout of the first annular portion 13. This is because the high frequency power supplied to the first electrode can be efficiently distributed to the electrode surface of the second electrode 12.

The surface of the second annular portion 14 is the second electrode 1.
It is preferable to dispose the electrode so that it is substantially flush with the second electrode surface.
This is because the lines of electric force at the peripheral portion of the wafer are vertical.
Further, it is to prevent the insulating film 12a on the side wall of the second electrode 12 from being destroyed by the plasma. However, in order to prevent the wafer from being lifted by the second annular portion 14, in consideration of the tolerance, the second annular portion 14 may be arranged such that the surface thereof is slightly lower than the electrode surface of the second electrode 12. preferable. That is, the surface of the second annular portion 14 is the second electrode 1
It is preferable to arrange it so that it is lower than the second electrode surface in the range of 0 to 0.5 mm.

A high frequency power source 21 is connected to the first electrode 11 and the second electrode 12 via a matching unit 20 and a transformer 22. A DC power supply 25 for wafer electrostatic attraction is connected to the second electrode 12 via a high frequency cut filter 24.

The case where the silicon oxide film is etched into a predetermined pattern by using the plasma processing apparatus having the above structure will be described below. The wafer 19 has, for example, a film thickness of 1 μm.
A silicon oxide film of about m is formed, and a resist pattern is further formed on the silicon oxide film.

First, the wafer 19 is placed on the second electrode 12. The first electrode 11 is lowered to set the electrode interval to a predetermined interval.

Next, the wafer is electrostatically attracted and fixed by supplying electricity from the wafer electrostatic attraction DC power supply 25. At this time, A
If an inert gas such as r is introduced into the reaction container 15 and electric power is applied from the high frequency power source 21 to generate plasma, the wafer can be adsorbed more quickly.

A predetermined flow rate of, for example, CF ₄ , CHF ₃ , Ar or the like is introduced into the reaction vessel 15 from the gas introduction passage 16 to set the inside of the reaction vessel 15 to a predetermined pressure. A predetermined power is applied from the high frequency power source 21 to turn the introduced gas into plasma. The generated plasma etches the silicon oxide film on the wafer 19.

By using the apparatus and method having the above structure, the electric field at the peripheral portion of the wafer can be sufficiently corrected, and etching can be performed on the wafer without causing a difference in etching shape between the central portion of the wafer and the peripheral portion of the wafer.

[0045]

Embodiments of the present invention will be described below. The apparatus used in this embodiment is the plasma processing apparatus shown in FIG.

The first electrode 11 is made of polycrystalline silicon, and its electrode surface has a diameter of 172.7 mm. The second electrode 12 is made by coating an aluminum electrode body with alumina, and the diameter of the wafer mounting surface is 147 mm.
It is.

(Test 1) Using the plasma processing apparatus described above, the silicon oxide film formed on the wafer was etched, and the materials of the first annular portion and the second annular portion, the uniformity of the etching rate, and the wafer central portion. And the difference in etching shape at the wafer peripheral portion were evaluated.

The uniformity of the etching rate was evaluated by measuring the etching rate at a predetermined position on the wafer and calculating the variation. The difference in etching shape is
The bottom diameters of the holes formed at the predetermined portions of the central portion 19a and the peripheral portion 19b are obtained and evaluated.

The shapes of the first annular portion 13 and the second annular portion 14 of the plasma processing apparatus used for the evaluation are as follows.
Regarding the shape of the first annular portion 13, the inner diameter Din is 173 mm, the outer diameter Dout is 223 mm, and the protrusion amount Hout from the electrode surface is 6.5.
mm. The inner diameter of the second annular portion 14 is 147 m.
m, and the outer diameter is 165 mm. In addition, the second annular portion 14
Are arranged so as to be substantially flush with the electrode surface of the second electrode 12, and when the second annular portion 14 is a conductor, they are electrically floated and connected to the second electrode 12 at high frequency. I chose

The materials used for the first annular portion 13 and the second annular portion 14 are silicon, which is a conductor, and Vespel (a product name: SPI, material: polyimide, manufactured by DuPont), which is an insulator. The test was conducted by changing the combination of the two.

The etching conditions are as follows. The gas flow rate is CF ₄ : 20 sccm, CHF ₃ : 30 sccm, Ar:
350 sccm, the pressure inside the reaction vessel 15 is 250 mTorr
And The high frequency is 400 kHz and the power is 8
00W. The distance between the first electrode 11 and the second electrode 12 was 10 mm. To evaluate the uniformity of the etching rate, a 6-inch silicon wafer having a silicon oxide film with a film thickness of 1 μm was used. For the evaluation of the difference in etching shape, a silicon wafer on which a resist having a hole pattern of 0.5 μm was formed was used.

FIG. 2 shows a first annular portion 13 and a second annular portion 14.
3 is a graph showing an etching rate when the above silicon or Vespell is used as a forming material for one or both of the above. In the figure, A shows the case where silicon is used for the first annular portion 13 and Vespell is used for the second annular portion 14. B in the figure is a case where the first annular portion 13 and the second annular portion 14 are made of vespel. C in the figure is a case where silicon is used for both the first annular portion 13 and the second annular portion 14. In the figure, D is a case where Vespell is used for the first annular portion 13 and silicon is used for the second annular portion 14.

As is apparent from FIG. 2, the first annular portion 1
3 and the second annular portion 14 is made of silicon (C)
, The etching rate at the peripheral edge was slightly decreased, and it was almost negligible. On the other hand, in the case where the first annular portion 13 and the second annular portion 14 are made of Vespell (B), the etching rate is extremely reduced when the distance from the center is 40 mm or more. When silicon is used for either one of the first annular portion 13 and the second annular portion 14 (A, D), when both the first annular portion 13 and the second annular portion 14 are made of vespel (B) The decrease in the etching rate of the peripheral edge portion 19b was slight.
However, all of them were insufficient in terms of uniformity of etching rate.

Table 1 shows the results of examining the difference in etching shape. In the table, the etching rate (average value) obtained from the evaluation of the etching rate uniformity and the etching rate uniformity are also shown.

[0055]

[Table 1]

As is clear from Table 1, the first annular portion 1
3 and the second annular portion 14 is made of silicon (C)
Has an etching rate uniformity of ± 2.88%,
Further, the difference in hole diameter between the central portion 19a and the peripheral portion 19b was 0.01 μm, which was a good result. On the other hand, when the first annular portion 13 and the second annular portion 14 are both made of Vespell (B), the difference in hole diameter is 0.03.
Although it was μm, which was slightly small, the uniformity of the etching rate was as large as ± 9.65%. Also, the first annular portion 1
3 and the second annular portion 14 is made of silicon (A, D), the etching rate uniformity is ± 5.
59 to 7.88%, first annular portion 13, second annular portion 14
Both were improved compared to the case of using Vespell (B), but the difference in hole diameter was as large as 0.05 to 0.06 μm.

(Test 2) Using the plasma processing apparatus described above, the shape of the first annular portion was changed, the silicon oxide film formed on the wafer was etched, and the etching shape at the wafer central portion and the wafer peripheral portion was examined. evaluated.

The first annular portion 13 and the second annular portion 14 of the plasma processing apparatus used for evaluation were made of polycrystalline silicon. The first annular portion 13 has an outer diameter Dout of 223 mm and an inner diameter Din of 173 mm, a constant outer diameter Dout of 173 mm, and an inner diameter Din of 160 mm, 158 mm, 156 mm,
Those having a diameter of 150 mm and having protrusion amounts Hout from the electrode surface of 11.5 mm, 9.5 mm, and 6.5 mm were prepared. The second annular portion 14 is arranged such that the surface of the second electrode 12 facing the first electrode 11 is substantially the same in height and is a flat surface, and is electrically floated so that the second annular portion 14 and the second electrode 12 have a high frequency. Connected to. Second annular part 1
The outer diameter of 4 was 165 mm.

The etching conditions are as follows. The gas flow rate is CF ₄ : 15 sccm, CHF ₃ : 18 sccm, Ar:
The pressure inside the reaction vessel 15 is 200 mTorr.
And The high frequency is 400 kHz and the power is 8
00W. For this evaluation, a 6-inch silicon wafer in which a silicon oxide film having a film thickness of 1 μm was formed and on which a resist having a hole pattern of 0.5 μm was formed was used.

FIG. 3 is a schematic sectional view showing a hole shape. FIG. 3 shows the first electrode 11 and the second electrode.
The results are obtained when the inter-electrode distance between the electrodes 12 is 15 mm and the protrusion amount Hout from the electrode surface of the first annular portion 13 is 11.5 mm. In FIG. 4, the distance between the first electrode 11 and the second electrode 12 is 13 mm, and the protrusion amount H from the electrode surface of the first annular portion 13 is H.
This is the result when out is 9.5 mm. FIG. 5 shows the results when the distance between the first electrode 11 and the second electrode 12 is 10 mm, and the protrusion amount Hout from the electrode surface of the first annular portion 13 is 6.5 mm. The hole cross-sectional shape was observed with a scanning electron microscope (SEM). The wafer central portion is the wafer central position, and the wafer peripheral portion is 1 to 1 from the wafer edge.
The position is 3 mm.

From the results of the hole shapes shown in FIGS. 3, 4 and 5, the inner diameter Din of the first annular portion 13 is 154.5-16.
It can be seen that when the distance is between 3.5 mm, a good etching shape can be obtained even in the peripheral portion of the wafer.

That is, it was confirmed that by setting the inner diameter Din within the range satisfying the formula (1) with respect to the wafer size DSi, a good etching shape can be obtained even in the peripheral portion of the wafer.

Similarly, from the results of the hole shapes shown in FIGS. 3, 4, and 5, the protrusion amount H from the electrode surface of the first annular portion 13 is obtained.
It was confirmed that by changing out according to the distance between the first electrode 11 and the second electrode 12, a good etching shape can be obtained even in the peripheral portion of the wafer within the above range of the inner diameter Din.

That is, by setting the protrusion amount Hout from the electrode surface of the first annular portion 13 within the range that satisfies the formula (3) for the interelectrode distance L between the first electrode 11 and the second electrode 12,
It was confirmed that a good etching shape could be obtained even in the peripheral portion of the wafer within the above range of the inner diameter Din.

As described above, the plasma processing apparatus of the present invention has the conductive first annular portion 13 and the conductive second annular portion 13.
An annular portion 14 is provided. Therefore, the wafer peripheral portion 19
The electric field of b is sufficiently corrected, and there is no difference in etching shape between the wafer central portion 19a and the wafer peripheral portion 19b. As a result, without impairing the uniformity of the etching rate,
It was possible to perform etching so as not to cause a difference in etching shape between the wafer central portion 19a and the wafer peripheral portion 19b.

Further, the plasma processing apparatus of the present invention is the second
By providing the second annular portion on the outer peripheral portion of the electrode, the second electrode is apparently enlarged. Therefore, it was confirmed that it can be easily applied to an apparatus provided with a second electrode having an electrostatic chuck structure.

The inner diameter Din, the outer diameter Dout of the first annular portion 13,
It was confirmed that the etching effect can be exhibited by setting the protrusion amount Hout from the electrode surface within a predetermined range with respect to the wafer size DSi and the interelectrode distance L.

It was also confirmed that the first annular portion 13 and the second annular portion 14 were made of silicon so that the wafer was not contaminated by impurities generated from these portions.

[0069]

As described above, the plasma processing apparatus and the plasma processing method of the present invention improve the electric field correction at the peripheral portion of the wafer, and the etching rate is equal between the central portion of the wafer and the peripheral portion of the wafer, and the difference in etching shape is caused. Can be etched so as not to generate.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a plasma processing apparatus of the present invention.

FIG. 2 is a graph showing an etching rate when the above silicon or Vespell is used as a material for forming one or both of the first annular portion and the second annular portion.

FIG. 3 is a schematic cross-sectional view showing a hole shape, showing the results when the distance between the first electrode and the second electrode is 15 mm, and the protrusion amount Hout from the electrode surface of the first annular portion is 11.5 mm. is there.

FIG. 4 is a schematic cross-sectional view showing the shape of a hole, showing the results when the distance between the first electrode and the second electrode is 13 mm and the protrusion amount Hout from the electrode surface of the first annular portion is 9.5 mm. is there.

FIG. 5 is a schematic cross-sectional view showing a hole shape, showing the results when the distance between the first electrode and the second electrode is 10 mm and the protrusion amount Hout from the electrode surface of the first annular portion is 6.5 mm. is there.

FIG. 6 is a schematic cross-sectional view showing a conventional plasma processing apparatus having an annular portion.

[Explanation of symbols]

 Reference Signs List 10 plasma processing apparatus 10a inner wall surface 11 first electrode 12 second electrode 12a insulating film 12b electrode body 13 first annular portion 14 second annular portion 15 reaction vessel 16 gas introduction passage 17 seal plate 18 insulator 19 wafer 19a wafer center Part 19b Wafer peripheral part 20 Matching device 21 High frequency power supply 22 Transformer 23 Electrode pressing ring 24 High frequency cut filter 25 DC power supply for wafer electrostatic attraction 30 Plasma processing device 31 First electrode 31a AC power supply 31b AC power supply 32 Second electrode 33 Ring part 38a insulator 38b insulator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Okumura 4-53-3 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd.

Claims (3)

[Claims] 1. A plasma processing apparatus comprising a first electrode and a second electrode on which a wafer facing the first electrode is mounted, the plasma processing apparatus comprising an outer peripheral portion of a surface of the first electrode facing the second electrode. A conductive first annular portion protruding toward the second electrode is provided,
A plasma processing apparatus, wherein a conductive second annular portion is provided on an outer peripheral portion of the second electrode. 2. The plasma processing apparatus according to claim 1, wherein the second electrode has an electrostatic chuck structure. 3. A plasma processing method using the plasma processing apparatus according to claim 1, wherein an inner diameter Din (mm), an outer diameter Dout (mm) of the first annular portion, and an electrode of the first electrode. The amount of protrusion Hout (mm) from the surface is defined by the following (1) and (2) with respect to the wafer size DSi (mm) of the wafer to be processed and the electrode distance L (mm) between the first electrode and the second electrode. ) And (3) are satisfied, the plasma processing is performed on the wafer mounted on the second electrode. 1.03 × DSi ≦ Din ≦ 1.09 × DSi (1) 1.10 × DSi ≦ Dout ≦ 1.20 × DSi (2) 0.7 × L-2.0 ≦ Hout ≦ 0.7 × L + 2.0 (3)