Structure for Preventing Peeling of Reaction Product, Process for Its Production and Process for the Production of a Semiconductor Device Using the Structure

Abstract

The peeling of a reaction product deposition film 50 is prevented, reducing the particle contamination of a material to be treated 16 by roughening the surfaces (adhesion preventing surfaces) of an outer liner 40 and inner liner 42 both made of aluminum installed as an adhesion preventing plate inside a chamber of a plasma etching device to a surface roughness within a constant range without carrying out alumite treatment.

Description

FIELD OF THE INVENTION

This invention pertains to the prevention of particle contamination on a material to be treated inside the chamber of a treatment device. In particular, it pertains to a reaction product peeling structure that can be used to prevent the formation of particles attributable to the reaction product inside a plasma etching device, a process for its production and a process for the production of a semiconductor device using the structure.

BACKGROUND OF THE INVENTION

The etching technique used in the production of semiconductor devices, liquid crystal displays, etc., involves masking a resist pattern formed on the surface of a material to be treated by lithography and processing a thin film of the resist to the desired circuit pattern. It is an essential process. In the main stream plasma etching process being carried out currently, a reactive treatment gas is ionized and dissociated with high-frequency discharge inside a chamber (treatment container) under vacuum to obtain a plasma containing radicals and ions, which are applied to a material to be treated (such as a semiconductor wafer, glass substrate, etc.), and reaction with the film to be etched on the substrate surface is carried out. The resulting reaction product byproduct in the vapor phase formed is mostly discharged outside the chamber with a vacuum discharge mechanism, but a portion remains inside the chamber and adheres to various parts inside the chamber, accumulating into layers of film.

To avoid such a reaction product from accumulating undesirably on non-exchanging members such as the inside walls of the chamber, susceptor (substrate loading and holding table), etc., adhesion prevention cover plates, that is, so-called adhesion preventing plates, have been used to cover them. In this case, the reaction product formed during the plasma etching process adheres on the adhesion preventing plates and accumulates. Therefore, the parts or members (chamber wall, susceptor, etc.), covered behind the preventing plates are protected from adhesion and deposition of the reaction product. This means special cleaning is not required.

In general, the preventing plates comprise aluminum treated with alumite and prepared as a freely exchangeable part to be placed inside the chamber. They are periodically exchanged with new ones in the course of using the plasma etching devices. Deposition films of the reaction product on the adhesion preventing plates tend to grow each time the plasma etching process is carried out, the thickness increases, and if they are left alone as they are, the film tends to peel off from the adhesion preventing plates. The peeled layer forms particles, which may fall on the substrate being treated, causing the product yield to drop. Therefore, before the accumulated film peels off, in general, the adhesion preventing plates inside the chamber are replaced with new ones when the limit usage time, that is the cumulative processing time reaches a certain level. The surfaces of the used preventing plates removed from the chamber are cleaned by scraping off the deposition film with a tool such as brush, etc., and subsequently, an alumite treatment is carried out again, and they are used again as a recycled part.

However, with the use of the adhesion preventing plates of the prior art as described above in a plasma etching device, the accumulated film of the reaction product may peel off relatively easily, and consequently from the viewpoint of preventing particle generation as described above, the exchange cycle of the adhesion preventing plates must be short, causing problems such as reduction in the availability of the plasma etching device, increased costs of adhesion preventing plate recycling, etc.

This invention was carried out in consideration of the problems of the prior art as described above, and the objective is to provide a structure for preventing peeling of reaction product enabling the prevention of any undesirable peeling of reaction product films inside the chamber of a plasma etching device and a process for its production.

SUMMARY OF THE INVENTION

To accomplish the above objective, the structure for preventing peeling of reaction product of this invention for a plasma treatment device is characterized in that a material to be treated is placed in a chamber, a required treatment gas is introduced into said chamber under vacuum, and the plasma etching of said material to be treated is carried out with a plasma formed with discharging of said treatment gas; and that the surface of a member, where the reaction product is to adhere in the case of said plasma etching treatment carried out in said chamber, is roughened so that the accumulated film of said reaction product is prevented from peeling off from the surface of said member.

In the configuration as described above, the surfaces of members or parts, where the reaction product adheres and accumulates inside the chamber, are suitably roughened, increasing the close contact adhesion of the reaction product with their surfaces, preventing film peeling and consequently reducing particle contamination on materials to be treated due to film peeling.

In a preferred embodiment of this invention, the reaction product comprises an organic polymer and contains carbon, hydrogen and fluorine. In this case, the treatment gas used is a halogen compound mainly comprising carbon and fluorine, and it may contain oxygen. This invention is suitably applicable to plasma etching of silicon nitrite or silicon oxide films.

In another preferred embodiment of this invention, the members comprise aluminum, and the surface is roughened without carrying out alumite treatment. With respect to the surface roughness, the mean roughness Ra is preferably in the range of 3 μm≦Ra≦9 μm, especially Ra=about 4.5 μm (4 μm≦Ra≦5 μm).

For the preparation of the structure for preventing peeling of reaction product of this invention, sandblasting treatment may be suitably carried out. In this case, the particles used for sandblasting are microparticles of alumina, silica or quartz with a particle size selected from the range of #70-#150.

Furthermore, the process for the production of a semiconductor device of this invention is characterized by including the following stages: carrying out a plasma treatment on a semiconductor wafer inside a chamber equipped with a reaction product adhesion prevention member; introducing a semiconductor wafer with the required resist pattern formed into the chamber; carrying out a plasma-etching treatment on said semiconductor wafer; discharging the reaction product adhesion prevention member inside the chamber; cleaning the adhesion prevention member discharged; placing the cleaned adhesion prevention member back into the chamber; introducing a semiconductor wafer with the required resist pattern formed into the chamber; and carrying out a plasma-etching treatment on said semiconductor wafer; and by the mean surface roughness Ra of the surface of said adhesion prevention member being in the range of 3 μm≦Ra≦9 μm.

The above process for the production of a semiconductor device may contain preferably a stage of carrying out a surface roughening treatment on the above adhesion prevention member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross sectional drawing showing the configuration of a plasma etching device in one embodiment of this invention.

FIG. 2 is a graph showing the relationship between the usage time of the adhesion preventing plates in the plasma etching device of the embodiment and the thickness of the film of reaction product deposited on the plates.

FIG. 3 is a drawing showing the state of the adhesion preventing surfaces of the adhesion preventing plates when the thickness of the reaction product deposition film in the embodiment reaches a certain constant level.

FIG. 4 is a drawing showing the state of the adhesion preventing surfaces of the adhesion preventing plates when the thickness of the reaction product deposition film in the comparative example reaches a certain constant level.

FIG. 5A is a schematic drawing explaining the action of this invention on the surface of the adhesion preventing plates.

FIG. 5B is a schematic drawing for explaining the action of the comparative example (prior art example) on the surface of the adhesion preventing plates.

FIG. 6 is a flow chart showing one example of the recycling method (procedures) for the adhesion preventing plates used in the embodiment.

REFERENCE NUMERALS AND SYMBOLS AS SHOWN IN THE DRAWINGS

In the figures, 10 represents a chamber, 12 a shower head shower head (upper electrode), 14 a susceptor (lower electrode), 16 a semiconductor wafer (material to be treated), 30 a high-frequency power source, 38 a discharge opening, 40 an outer liner (adhesion preventing plate), 42 an inner liner (adhesion preventing plate), 50 a reaction product deposition film

DESCRIPTION OF THE EMBODIMENT

According to the structure for preventing peeling of reaction product, process for its production and process for the production of a semiconductor device using the structure of this invention, the undesired peeling of reaction product inside the chamber of a plasma etching device is conveniently preventable because of the configuration and action as described above.

The preferred embodiment of this invention is explained with reference to the attached drawings as follows.

FIG. 1 shows a configuration of a capacitively coupled plasma etching device with one preferred embodiment of this invention applied. This plasma etching device has a chamber 10 that is a cylindrical hollow body made of aluminum (Al). An interior shower head 12 functioning also as an upper electrode and a susceptor 14 also functioning as a lower electrode are provided on the top and bottom, respectively, in parallel with the required spacing. A material to be treated, for example semiconductor wafer 16, is placed on the susceptor 14 and held by Coulomb force of an electrostatic chuck 18 installed on the top of the susceptor as a single body. Furthermore, an annular focus ring 20 made of, for example, polycrystalline silicon is installed in a freely detachable manner at the outer circumference of the susceptor 14, surrounding the semiconductor wafer 16.

The desired treatment gases (etching gas), which are fed from their supply sources (not shown in the figure) through supply lines 22A and 22B, are mixed in the shower head 12, and the treatment gas mixture is jetted out as a shower toward the susceptor 14 from a multiple-hole gas discharge outlet. The shower head 12 is installed in a freely detachable manner at the top surface of the chamber 10 through a top cover 24 made of aluminum so that it is easily removable for periodical cleaning and maintenance, and it is electrically grounded via the top cover 24 or chamber 10.

The susceptor 14 is affixed on a columnar or cylindrical susceptor support 28 made of, for example, aluminum installed at the bottom of the chamber 10 through an insulation plate 26. The susceptor 14 is electrically connected through a matching box 32 to a high-frequency power source 30 installed outside of the chamber 10.

The chamber 10 is configured as a sealable and pressure-reducible treatment container, the chamber side wall is provided with a wafer inlet-outlet opening 34 for loading/unloading semiconductor wafer 16 and gate valve 35, and at the bottom of the chamber, an exhaust opening 38 connected to a vacuum pump (not shown in the figure) through a exhaust pipe 36 is installed.

Inside the chamber 10, an outer liner 40 covering the inner wall of the chamber and an inner liner 42 covering the outer circumferential surface of the susceptor 14 or susceptor support 28 are both installed in a freely detachable manner as adhesion preventing plates. The outer liner 40, in particular, comprises a cylindrical side wall liner unit 40a extended in the vertical direction to cover the side wall of the chamber 10 and circular ceiling liner unit 40b extended in the horizontal direction to cover the ceiling of the chamber 10 around the shower head 12; at the top end of the side wall liner unit 40a, the outer circumferential edge of the ceiling liner unit 40b is connected as a single body. The sidewall line unit 40a has an inner wafer inlet-outlet opening 44 and shutter 46 at a site corresponding to the gate valve 35. The inner liner 42 has a circular exhaust space 48 connecting to the exhaust opening 38 at the bottom of the chamber installed facing the side wall liner unit 40a of the outer liner 40.

Both outer liner 40 and inner line 42 are made of aluminum, and their front surfaces are roughened to a suitable degree within the desired range explained later in detail.

This plasma etching device uses suitably a silicon nitride or silicon oxide film formed on the main surface of the semiconductor wafer 16 as a material to be etched. In the case of plasma etching, a fluorine compound such as CH_xF_4-x (where x=1, 2 or 3) and oxygen gases are fed through a first treatment gas supply line 22A and a second treatment gas supply line 22B, respectively to the shower head 12, the gases are mixed inside the shower head 12, and the gas mix is discharged towards semiconductor wafer 16 on the susceptor 14 as shown with arrows in the figure through a multiple-hole gas discharge outlet. On the other hand, the inner pressure of the chamber 10 is reduced to a certain vacuum level with a vacuum pump, and the required constant high frequency at a required power level is applied to the susceptor 14 from the high-frequency power source 30.

As a result, plasma excitation of high frequency power is carried out for the treatment gas mixture in the region (plasma generation space) between the shower head (upper electrode) 12 and susceptor (lower electrode) 14. This plasma excitation causes the treatment gases to break down and activate to form, for example, active species of fluorine, oxygen, etc. These generated active species are molecules and atoms in their excited states such as ions, neutral radicals, etc., and they are in a ready state for chemical reaction, and reaction with the material to be etched on the semiconductor wafer 16 is easily carried out. The vapor phase product formed as a result of this reaction is an organic polymer containing elements C, H and F, and it is mostly discharged together with other unconsumed active species and treatment gases as an exhaust gas mixture to the outside of the chamber 10 from the exhaust opening 38 through the exhaust space 48.

However, a portion of the reaction product is not discharged outside the chamber 10, but adheres on the surrounding walls, that is, inner wall (adhesion preventing surface) of the outer liner 40 and outer wall (adhesion preventing surface) of the inner liner 42, forming a deposition film 50. As the plasma etching process is repeatedly carried out, the film thickness of this reaction product deposition film 50 increases. The outer line 40 and inner liner 42 act as a shield; they allow the adhesion and deposition of the reaction product on their respective front surfaces (adhesion preventing surface), and consequently, the parts or members (inner wall of the chamber 10 and outer circumferential surface of the susceptor support 28) covered behind them have very little or essentially no adhered or deposited reaction product.

In this embodiment, the adhesion preventing surfaces of the outer liner 40 and inner liner 42 are suitably roughened to a level within the required range so that the deposition film 50 of the reaction product is effectively prevented or inhibited from peeling off from the two liners 40 and 42. Specifically, with respect to the surface roughness of the adhesion preventing surfaces of the liners 40 and 42, the lower limit of the mean roughness Ra satisfies the condition 3 μm≦Ra. If Ra is below 3 μm, the close contact adhesion of the reaction product deposition film 50 becomes poor, as explained in detail later, and film peeling may occur. Furthermore, the upper limit of Ra satisfies the condition Ra≦9 μm. If Ra is over 9 μm, film peeling due to a difference in thermal expansion coefficients between the material (aluminum) of the two liners 40 and 42 and reaction product deposition film 50 may occur. Incidentally, in this embodiment, the film peeling reducing effect was confirmed to be highest at Ra=about 4.5 μm (4 μm≦Ra≦5 μm), within this range of 3 μm≦Ra≦9 μm.

FIG. 2 shows the relationship between the net adhesion preventing plate usage time (cumulative processing time) of repeated plasma etching carried out on silicon nitride in the plasma etching device of this embodiment and the film thickness of the reaction product deposition film 50 on the adhesion preventing plates (outer liner 40 and inner liner 42). As apparent from the results shown in the figure, the film thickness of the reaction product deposition film 50 increases monotonically with an almost constant proportional coefficient C (C=1.3384 in the example shown in the figure) as the usage time increases.

In the embodiment, the reaction product deposition film 50 was found to be adhered strongly on the inner wall (adhesion preventing surface) of the outer liner 40, causing no film peeling at all as schematically shown in FIG. 3 even after the total usage hours reached 115 hours, and the thickness of the reaction product deposition film 50 reached 153 μm. Furthermore, although not illustrated, peeling of the reaction product deposition film 50 was also not observed at all in the inner liner 42.

On the other hand, when the adhesion preventing surfaces of the outer liner 40 and inner liner 42 were treated with alumite 52 similar to the previous method as a comparative example, in the stage when the thickness of reaction product deposition film 50 was still 67 μm when the usage time exceeded 50 h, the reaction product deposition film 50 peeled off in a belt shape from the inner wall (adhesion preventing surface) of the outer liner 40, exposing the alumite layer 52 as shown in FIG. 4. Peeling of the reaction product deposition film 50 was also observed in the inner liner 42 (not illustrated). Incidentally, the mean roughness Ra of the alumite layer 52 formed was less than 2 μm.

As described above in detail, it is possible to inhibit the peeling of the reaction product deposition film 50, thus reducing the particle contamination on the surface of the semiconductor wafer 16 by roughening the adhesion preventing surfaces of the outer liner 40 and inner liner 42 both made of Al and functioning as an adhesion preventing plate inside the chamber 10 with a surface roughness level within a constant range (3 μm≦Ra≦9 μm) without any alumite treatment. Furthermore, because of the difficulty of the reaction product deposition film 50 peeling off from the outer liner 40 and inner liner 42, it is possible to delay or extend the interval (cycle) of the periodical cleaning inside the chamber 10 and liner exchange, and consequently, it is possible to improve the availability of the device and reduce the recycling costs of the adhesion preventing plates. The function of the adhesion preventing plates (adhesion preventing surfaces) is explained with reference to the schematic drawings of FIG. 5 as follows. FIG. 5A shows a case in which the surface roughness of the adhesion preventing surfaces is set to Ra=4.5 μm according to this invention. In this case, the organic polymer as the reaction product 50 containing elements C, H and F formed as a result of plasma etching of a silicon nitride or silicon oxide film is adhered and deposited, for example, as fiber bundles shown as circles in the figure, in a manner with the lowest layer portion of the film filling the valleys of the adhesion preventing plate surface. In this case, the contact area between the fibers of the reaction product 50 and adhesion preventing surfaces is great, and consequently, the bonding strength (bonding force) between the two is great.

On the other hand, FIG. 5B shows a case in which the surface roughness of the adhesion preventing plates is set at Ra=2 μm. If the surfaces of the adhesion preventing plates made of Al are treated with alumite as in the prior art, the surface roughness may be fine, as shown in the figure. In this case, the organic polymer of the reaction product 50 cannot enter the valleys on the surface; it adheres and deposits on the top of projections on the surface. Consequently, the contact area is small, the close adhesion is poor, and film peeling may occur at the interface.

In general, the adhesion of the organic polymer formed as the reaction product to the surface of the adhesion preventing plates is based on bonding by physical adsorption at the atomic or molecular level, and it is not as strong. However, with the adhesion preventing plates of this invention, the adhesion power, originally as strong, is supplemented with a suitable surface roughness level, thus increasing the adhesion or bonding area of the reaction product deposition film, and peeling of the film is effectively prevented.

One example of the method of recycling the adhesion preventing plates (outer liner 40 and inner liner 42) in this embodiment is explained with reference to the flow chart shown in FIG. 6 as follows. First, in the case of periodical exchange of the adhesion preventing plates inside the chamber 10, plasma-cleaning procedures are carried out prior to removing the in-use outer liner 40 and inner liner 42. Specifically, as a cleaning gas, a gas mixture of fluorine-type gas not containing carbon such as NF₃ (nitrogen trifluoride) and oxygen gas is introduced into the chamber 10, and plasma excitation of these gases is carried out to clean the surface of the inside of the chamber 10 (Step S1). As a result of this plasma cleaning, a portion of the reaction product deposition film 50 on the adhesion preventing surfaces of the liners 40 and 42 is removed.

After the plasma cleaning carried out as described above, the chamber top cover 24 and shower head 12 are removed, and the outer liner 40 and inner liner 42 are removed from the chamber 10. The reaction product deposition film 50 remaining on the adhesion preventing surfaces of liners 40 and 42 is scraped off (Step S2). This removal is carried out by scraping the surface with a nonwoven fabric or resin brush.

Subsequently, the surfaces of the liners 40 and 42 are cleaned thoroughly with a suitable method such as soaking in pure water and carrying out ultrasonic cleaning, cleaning with a chemical solution, etc. (Step S3)

Subsequently, the adhesion preventing surfaces of the liners 40 and 42 sandblasted (Step S4). The sand used in this sandblasting comprises microparticles of silica, quartz, alumina, etc., with a particle size in the range of #70-#150, preferably #100. As a result of this sandblasting, the surfaces of the liners 40 and 42 are roughened to the surface roughness level within the above range (3 μm≦Ra≦9 μm.). The microparticles used in this sandblasting are preferably sieved so that the particle size is uniform. Incidentally, the particle size corresponds to the number of microparticles which can be arranged in a space of 10 mm squares.

The adhesion preventing surfaces of the outer liner 40 and inner liner 42 roughened as a result of sandblasting are cleaned (Step S5). This cleaning stage is carried out with a cleaning method such as ultrasonic or cleaning chemical solution cleaning so that any particles adhered on the surfaces of the liners 40 and 42 are effectively removed.

The recycling process of the outer liner 40 and inner liner 42 is carried out as described above. The outer liner 40 and inner liner 42 after the above recycling processing are installable inside the chamber 10 of the plasma etching device at the time of periodical exchange for recycled reuse.

Incidentally, after cleaning state S3, the surface roughness Ra of the adhesion preventing surfaces of the liners 40 and 42 may be measured with a surface roughness meter. The subsequent sandblasting may be carried out only when the Ra value is outside of the allowable range. In general, the adhesion preventing surfaces 45 tend to become smooth after repeated use as an adhesion preventing plate inside the chamber 10 and carrying out the above steps S1, S2 and S3. Therefore, if the film roughness measurement result is Ra≦3 μm, the sandblasting as described above may be carried out in step S4. Alternatively, the plasma cleaning (Step S1) inside the chamber 10 may be omitted, and the recycling processing may be carried out after scraping off the reaction product deposition film 50 (Step S2).

According to this invention, it is also possible to achieve the same peeling prevention or inhibition effect as that described above on the reaction product deposition film on various parts or members other than the adhesion preventing plates used inside the chamber of a plasma etching device if their surface is roughened to a level within the above constant range (3 μm≦Ra≦9 μm). In this case, the materials for such a roughening treatment may include, for example, quartz glass, aluminum nitride, stainless steel, etc., in addition to Al.

This invention is applicable to a plasma etching device for a silicon nitride or silicon oxide film used as a material to be etched. Remarkable effects are not obtained with other types of plasma treatment devices such as PECVD (plasma enhanced chemical vapor deposition) devices, etc.

This invention has been explained with a preferable embodiment, but the above embodiment does not necessarily limit this invention. It is possible for those skilled in the art to make various modifications and changes without deviating from the technical teaching and technical range of this invention as illustrated in specific embodiments. For example, the surface roughening treatment applied on the surfaces of various parts or members such as adhesion preventing plates, etc., for the purpose of inhibiting the reaction product deposition film from peeling off in the above embodiment may be carried out with a method other than the sandblasting described above, and specifically, it may be carried out with surface etching with a chemical or physical friction. In addition, the material to be treated with this invention is not necessarily limited to semiconductor wafers, and for example, it may be a glass substrate used for LCDs, etc. Moreover, the plasma etching device to which this invention is applicable is not necessarily limited to the type described above in the embodiments. For example, the structure for preventing peeling of reaction product of this invention is also applicable to an anode couple type plasma etching device, wherein the lower electrode is grounded, and high frequency is applied to the upper electrode.

Claims

1. A structure for preventing peeling of reaction product in a plasma treatment device, said structure comprising a member wherein a surface of said member is roughened so that an accumulated film of said reaction product is prevented from peeling off from the surface of said member.

2. The structure for preventing peeling of reaction product of claim 1, wherein said reaction product comprises an organic polymer.

3. The structure for preventing peeling of reaction product of claim 1, wherein said plasma treatment device holds a material to be treated that has an etchable silicon nitride or silicon oxide film.

4. The structure for preventing peeling of reaction product of claim 1, wherein said member comprises aluminum.

5. The structure for preventing peeling of reaction product of claim 1, wherein the mean roughness Ra of the surface of said member is in the range of 3 μm≦Ra≦9 μm.

6. The structure for preventing peeling of reaction product of claim 5, wherein the mean roughness Ra of the surface of said member is in the range of 4 μm≦Ra≦5 μm.

7. The structure for preventing peeling of reaction product of claim 1, wherein said member has a first adhesion preventing plate covering at least a portion of the inner wall of a chamber of said plasma treatment device.

8. The structure for preventing peeling of reaction product of claim 7, wherein said member has a second adhesion preventing plate covering at least a portion of a table holding a material to be treated.

9. A process for the production of a structure for preventing peeling of reaction product, comprising the step of roughening a surface of a member so that an accumulated film of said reaction product is prevented from peeling off from the surface of said member.

10. The process of claim 9, wherein said roughening is carrying out by a sandblasting treatment on the surface of said member.

11. The process for the production of a structure for preventing peeling of reaction product of claim 10, wherein particles used for the sandblasting are microparticles of alumina, silica or quartz having a particle size in the range of #70-#150.

12. The process of claim 9, wherein said member comprises aluminum.

13. The process of claim 9, wherein a mean roughness Ra of the surface of said member is in the range of 3 μm≦Ra≦9 μm.

14. The process of claim 13, wherein the mean roughness Ra of the surface of said member is in the range of 4 μm≦Ra≦5 μm.

15. The process of claim 9, wherein said member has a first adhesion preventing plate covering at least a portion of the inner wall of a chamber of said plasma treatment device.

16. The process of claim 15, wherein said member has a second adhesion preventing plate covering at least a portion of a table holding a material to be treated.

17. A process for the production of a semiconductor device comprising the steps of:

carrying out a plasma treatment on a semiconductor wafer inside a chamber equipped with a reaction product adhesion prevention member, wherein the adhesion prevention member comprises a mean surface roughness Ra in the range of 3 μm≦Ra≦9 μm;

introducing a semiconductor wafer with the required resist pattern formed into the chamber;

carrying out a plasma-etching treatment on said semiconductor wafer;

discharging the reaction product adhesion prevention member inside the chamber;

cleaning the discharged adhesion prevention member;

placing the cleaned adhesion prevention member back into the chamber;

introducing a semiconductor wafer with the required resist pattern formed into the chamber;

and carrying out a plasma-etching treatment on said semiconductor wafer.

18. The process for the production of a semiconductor device of claim 17, wherein the surface roughening treatment is carried out on said adhesion prevention member discharged from the chamber.

19. The process of claim 18, wherein the surface roughening treatment comprises sandblasting.

20. The process of claim 19, wherein particles used for the sandblasting are microparticles of alumina, silica or quartz having a particle size in the range of #70-#150.