JP2001203187A - Component for semiconductor manufacturing machine and the machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide components of a semiconductor manufacturing device with less impurities contamination than before when irradiated with a plasma and excellent in durability. SOLUTION: A part 1 used for a semiconductor manufacturing machine that uses plasma comprises a base material 11 of carbon material, and a coat 12 of silicon carbide formed on the surface of base material 11 by a CVD method. The film thickness of the coat 12 is preferred to be 80 μm or thicker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component used in a semiconductor manufacturing apparatus using plasma.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a semiconductor manufacturing apparatus using plasma is used. For example, the plasma etching apparatus performs a process of exposing the silicon surface by exposing only the photosensitive region in the photosensitive film by exposing the silicon wafer having undergone the exposure and development processes to gas plasma. As shown in FIG. 3, which will be described later, the plasma etching apparatus includes a pair of upper and lower electrodes 52 and 53 disposed in a chamber 51. Gas plasma is supplied from the upper electrode 52 to the lower electrode 53. It is configured as follows. Then, the silicon wafer 8 as a material to be processed is placed on the upper surface of the lower electrode 53, and irradiation with gas plasma is performed, whereby the above-described silicon surface exposure processing can be performed.

It is necessary to arrange a dummy ring around the outer peripheral portion of the silicon wafer 8. The dummy ring is used to uniformly irradiate the gas plasma also on the outer peripheral portion of the silicon wafer, thereby suppressing in-plane variation in the amount of abrasion of the silicon wafer due to the plasma and performing uniform etching.

[0004]

By the way, components for semiconductor manufacturing equipment, such as a conventional dummy ring, are gradually degraded by being irradiated with plasma during plasma processing. Specifically, the portion irradiated with the plasma is separated into, for example, powder and scatters or gasifies, and is gradually consumed. In addition, the reaction products and the scattered particles may adhere to the silicon wafer as particles, which may cause the particles to be defective.

[0005] Therefore, in recent years, for the components used in this type of apparatus, a change from a material such as aluminum or carbon, which tends to generate particles, to another material, which does not easily generate particles, has been attempted.

As such a new material, a high-purity silicon carbide sintered body, a silicon material, and the like have been proposed. However, these materials generate less particles than aluminum and carbon materials, but if they are used for a long time, the crystal grains on the surface layer fall off due to gas plasma irradiation, which is the cause of the particle generation. Becomes

As described above, conventional parts for semiconductor manufacturing equipment cannot be used stably for a long period of time. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides a component for a semiconductor manufacturing apparatus which can be used stably for a long time without contaminating a silicon wafer, and a semiconductor manufacturing apparatus using the same. It is assumed that.

[0008]

According to a first aspect of the present invention, there is provided a component for a semiconductor manufacturing apparatus used in a semiconductor manufacturing apparatus utilizing plasma, wherein the component for a semiconductor manufacturing apparatus includes a base made of a carbon material, A component for a semiconductor manufacturing apparatus, comprising: a film made of silicon carbide formed by a CVD method on a surface of a base material.

The carbon material is, for example, a material using carbon such as graphite, and is particularly preferably an isotropic graphite material or a C / C composite. In the case of an isotropic graphite material, the anisotropic ratio of the thermal expansion coefficient is 1.20 or less, and the total amount of pores measured by the mercury intrusion method is 0.095 cc / g.
And the average pore radius is from 0.1 μm to 1.
Those having a thickness of 5 μm have the strongest bond with the silicon carbide film. Here, the mercury intrusion method was used to measure mercury surface tension of 480 dyne / cm, contact angle of 140 °, and maximum pressure of 10
This is performed under the condition of 0 MPa. The value of the average pore diameter is defined as the pore radius at which 50% of the cumulative pore volume becomes.

The above-mentioned film uses silicon carbide formed by the CVD method as described above. This film can be obtained by forming a film directly on the surface of the base material by the CVD method. Further, the coating may be provided on the entire surface of the base material, or may be provided partially on a portion irradiated with plasma.

Next, the operation of the present invention will be described. The component for a semiconductor manufacturing apparatus of the present invention comprises the above-described base material and a film provided on the surface thereof. Therefore, the durability of the component for semiconductor manufacturing equipment depends on the durability of the film.
Here, in the present invention, silicon carbide (hereinafter, referred to as CVD-SiC) formed by a CVD method is used as the film. This CVD-SiC can be SiC which is superior in high purity and denseness as compared with a conventionally used high-purity silicon carbide sintered body. For this reason, the film made of CVD-SiC can suppress the falling of the crystal grains when the plasma is irradiated, as compared with the conventional case.
The generation of particles can be reduced as compared with the related art. In addition, since the deterioration due to the consumption of the film is suppressed as compared with the related art, the durability of the entire component for a semiconductor manufacturing apparatus having the excellent film can be improved.

Next, it is preferable that the film has a thickness of 80 μm or more. As a result, it is possible to sufficiently secure a period until the base material is exposed due to the wear deterioration of the film, and it is possible to reduce the frequency of replacement of parts for semiconductor manufacturing equipment.

Further, as in the third aspect of the present invention, the content of impurities in the base material is preferably 1 to 50 ppm. The content of impurities in the base material is 50 pp
When the thickness exceeds m, the purity of the film is reduced by the impurities when the film made of the CVD-SiC is formed on the surface of the substrate, and the impurities are scattered by gas plasma irradiation to contaminate the silicon wafer. Or the impurity concentration may increase, thereby deteriorating the durability. On the other hand, it is most preferable that there is no impurity at all, but it is difficult to reduce the content of the impurity to less than 1 ppm in the current base material manufacturing technology.

Further, as in the invention of claim 4, the content of impurities in the film is preferably 10 ppm or less. The content of impurities in the film is 10 pp
If it exceeds m, impurities may be scattered by the irradiation of the gas plasma to contaminate the silicon wafer, and a desired durability may not be obtained.

Further, as in the invention of claim 5, the amounts of boron, phosphorus and iron contained as impurities in the film are preferably 1 ppm or less. When the content of these impurities exceeds 1 ppm, regardless of the total impurity content, the impurity is scattered by the irradiation of the gas plasma to contaminate the silicon wafer, thereby making the silicon wafer defective or having a desired durability. There is a problem that it is difficult to obtain the property.

According to a sixth aspect of the present invention, the component for a semiconductor manufacturing apparatus can be a dummy ring arranged on an outer periphery of a silicon wafer in the semiconductor manufacturing apparatus. In this case, a highly durable dummy ring can be obtained without fear of contaminating the silicon wafer, and by using this, a high-quality silicon wafer can be manufactured.

According to a seventh aspect of the present invention, there is provided a semiconductor manufacturing apparatus using the component for a semiconductor manufacturing apparatus according to any one of the first to sixth aspects. Since the semiconductor manufacturing apparatus of the present invention uses the above-described excellent parts for a semiconductor manufacturing apparatus, a high-quality silicon wafer can be stably manufactured for a long period of time.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A component for a semiconductor manufacturing apparatus according to an embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIG. 3, in the semiconductor manufacturing process, the silicon wafer 8 that has been exposed and developed is exposed to gas plasma to selectively remove only the photosensitive region in the photosensitive film to expose the silicon surface. 1 shows an example of a dummy ring 1 which is a component for a semiconductor manufacturing apparatus used in a plasma etching apparatus 5 for performing a process to be performed.

As shown in FIGS. 1 and 2, the dummy ring 1 of this embodiment includes a base material 11 made of a carbon material and a base material 11 made of a carbon material.
Silicon carbide (CVD-
A film 12 made of SiC). The overall shape has a ring shape and a concave portion 19 for mounting the silicon wafer 8 on the upper surface of the inner peripheral portion thereof. In the dummy ring 1 of this embodiment, the entire outer surface of the substrate 11 is covered with the CVD-SiC film 12.

In manufacturing the dummy ring 1, first, an isotropic graphite material (trade name: T-4, manufactured by IBIDEN Co., Ltd.) is supplied with an outer diameter of 250 mm and an inner diameter of 190 mm.
Lathe processing was performed to a thickness of 3 mm, and then high-purification treatment was performed in a halogen gas atmosphere at 2000 ° C. to produce a substrate 11 made of graphite. The surface of the substrate 11 is CVD
-Directly forming the film 12 of SiC;

Specifically, the base material 11 is not shown
Set in a VD device, temperature 1350 ° C, vacuum degree 150
Under the condition of Torr, methyl chlorosilane was supplied as a reaction gas and hydrogen was supplied as a carrier gas, and the film 12 was formed by thermal decomposition. As a result, the film thickness becomes 20
The coating 12 of 0 μm was formed uniformly on the surface of the substrate 11.

The purity of each part of the dummy ring 1 obtained in this example was high. Specifically, as a result of the measurement by the GDMS method, the base material 11 was found to have high purity with an impurity content of 5 ppm or less. The coating 2 had an impurity content of 2 ppm or less, and the amounts of boron, phosphorus, and iron contained as impurities were all 1 ppm or less.

Next, a plasma etching apparatus 5 using the dummy ring 1 will be briefly described with reference to FIG. As shown in the figure, the plasma etching apparatus 5 of the present embodiment includes a pair of upper and lower electrodes 52 and 53 disposed in a cylindrical chamber 51, and performs gas plasma from the upper electrode 52 to the lower electrode 53. Is provided. An exhaust port 514 for evacuating the inside is provided on the side surface of the chamber 51.

The upper electrode 52 is made of a conductive material such as SiC, silicon, aluminum, or carbon, and is provided with a large number of through holes 521 for guiding a gas supplied from above between the electrodes. The upper electrode 52 is disposed so as to be engaged with a support ring 512 projecting inward from the chamber 51.

The lower electrode 53 is disposed above the stage 54. The lower electrode 53 is provided with a convex portion 531 at the center and a concave portion 532 for disposing the dummy ring 1 around the convex portion 531. The dummy ring 1 is set and used in the depression 532 so as to surround the projection 531. The silicon wafer 8 is held in the concave portion 19 of the dummy ring 1 as shown in FIGS.

Next, the silicon wafer 8 was actually processed using the plasma etching apparatus 5, and the durability of the dummy ring 1 and the quality of the obtained silicon wafer 8 were evaluated. As a result, when the plasma etching treatment was performed under the same conditions as in the conventional case, the consumption of the dummy ring 1 progressed slowly, showing excellent durability, and the quality of the obtained silicon wafer 8 was also reduced due to particles and contamination. Not an excellent one.

Embodiment 2 In this embodiment, in order to quantitatively evaluate the excellent effect of the dummy ring 1 (embodiment E1) in Embodiment 1, four types of dummy rings for comparison (conventional example) were used. C1, Comparative Examples C2 and C3) were prepared and tested together with Example E1.

(Conventional Example C1) In Conventional Example C1, 50% by weight of α-type silicon carbide powder and β-type crystal silicon carbide powder were mixed.
Each mixture was used as a raw material powder. 5 parts by weight of polyvinyl alcohol and 300 parts by weight of water were mixed with 100 parts by weight of the mixture, and then mixed in a ball mill for 5 hours or more to obtain a uniform mixture. The mixture is dried for a predetermined time to remove water to some extent, then an appropriate amount of the dried mixture is collected and granulated, and the granules are filled in a mold and pressed to produce a disc-shaped formed body. did. Next, this formed body was heated to 2000 ° C., which is the maximum temperature, in an argon gas atmosphere. Conventional example C1
Is a dummy ring as a conventional product manufactured by machining this high-purity silicon carbide sintered body.

(Comparative Example C2) Comparative Example C2 is an example in which the purity of the substrate 11 and the coating 12 of the dummy ring 1 in Embodiment 1 is reduced. That is, the base material of Comparative Example C2 is a base material made of graphite manufactured by the same method as the dummy ring 1 in Embodiment Example 1, but has an impurity content of 200 ppm measured by the GDMS method. Also,
The film having a thickness of 200 μm formed on the surface of the base material in the same manner as in Embodiment 1 had an impurity content of 50 ppm.

Comparative Example C3 Comparative Example C3 is an example in which only the impurity amount of a specific element in the coating 12 of the dummy ring 1 in Embodiment 1 is increased. That is, the base material of Comparative Example C3 is a base material made of graphite prepared by the same method as the base material 11 of Embodiment 1. This substrate is GDM
As a result of measurement by the S method, the impurity content was high purity of 30 ppm or less. The film having a thickness of 300 μm uniformly formed on the surface of the base material in the same manner as in the first embodiment has a total impurity content of 5 ppm or less, and boron and phosphorus contained as impurities are 1 ppm or less. However, the content of iron in this film is 1.5 ppm.

Next, in the test, C ₄ F ₈ , Ar, O ₂ , and CO were introduced as a gas under a reduced pressure at a power of 1500 W under a predetermined condition using the plasma etching apparatus 5, and silicon was removed at predetermined time intervals. The wafer was replaced, and continuous plasma etching evaluation for 50 hours was performed. Then, the amount of consumption of the dummy ring was measured and compared with the quality of the silicon wafer.

FIG. 4 shows the measurement results of the consumption amount. In the figure, the type of the dummy ring is plotted on the horizontal axis, and the consumption (μm) is plotted on the vertical axis. FIG. 5 shows the result of calculating the defect rate from the number of defective wafers with respect to the number of processed silicon wafers for the quality of the silicon wafer. In the figure, the horizontal axis indicates the type of the dummy ring, and the vertical axis indicates the defect rate (%).

As can be seen from FIGS. 4 and 5, the dummy ring 1 having the CVD-SiC film 12 according to the present invention (Example E1) consumes less slowly than the conventional example C1. It can be seen that the defective rate of the silicon wafer is smaller than that of the comparative examples C2 and C3, and the quality of the obtained silicon wafer is excellent.

[0034]

As described above, according to the present invention, it is possible to provide a component for a semiconductor manufacturing apparatus which is free from impurity contamination when subjected to plasma irradiation and has excellent durability as compared with the prior art.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor manufacturing device component (dummy ring) according to a first embodiment.

FIG. 2 is a perspective view of a semiconductor manufacturing device component (dummy ring) and a silicon wafer in the first embodiment.

FIG. 3 is an explanatory diagram illustrating a configuration of a plasma etching apparatus according to the first embodiment.

FIG. 4 is an explanatory diagram showing a consumption amount measurement result in the second embodiment.

FIG. 5 is an explanatory diagram showing the quality of a silicon wafer in a second embodiment.

[Explanation of symbols]

 1. . . 10. parts for semiconductor manufacturing equipment (dummy ring); . . Base material, 12. . . Film, 5. . . 7. plasma etching equipment, . . Silicon wafer,

Continued on the front page (72) Inventor Keiichi Sakashita 300 Aoyagi-cho, Ogaki-shi, Gifu FBI term in the Aoyagi plant of IBIDEN CO., LTD. 5F004 AA16 BB18 BB23 BB28 BB29 BC08 5F045 AA08 BB14 DP02 EF05 EM06 EM09

Claims (7)

[Claims] 1. A component for a semiconductor manufacturing apparatus used in a semiconductor manufacturing apparatus utilizing plasma, wherein the component for a semiconductor manufacturing apparatus is formed by a base material made of a carbon material and a surface of the base material formed by a CVD method. And a film made of silicon carbide. 2. The component for a semiconductor manufacturing apparatus according to claim 1, wherein the film has a thickness of 80 μm or more. 3. The component for a semiconductor manufacturing apparatus according to claim 1, wherein the content of the impurity in the base material is 1 to 50 ppm. 4. The method according to claim 1, wherein:
A component for a semiconductor manufacturing apparatus, wherein the content of impurities in the film is 10 ppm or less. 5. The method according to claim 1, wherein:
A component for a semiconductor manufacturing apparatus, wherein the amounts of boron, phosphorus, and iron contained as impurities in the film are each 1 ppm or less. 6. The method according to claim 1, wherein:
The component for a semiconductor manufacturing device, wherein the component for a semiconductor manufacturing device is a dummy ring arranged on an outer periphery of a silicon wafer in the semiconductor manufacturing device. 7. A semiconductor manufacturing apparatus using the component for a semiconductor manufacturing apparatus according to any one of claims 1 to 6.