JPH07130666A - Method of preventing exfoliation of deposition film in semiconductor fabrication apparatus - Google Patents

Abstract

PURPOSE:To prevent a deposition film yielded by permitting a reaction product produced in a semiconductor fabrication apparatus to adhere to a clamp from exfoliating from the surface.of the clamp by forming a coated film on the surface of the clamp serving to fix a wafer on the stage of the apparatus. CONSTITUTION:In a semiconductor fabrication apparatus in which a wafer 21 is fixed to a stage 57 with a clamp 1 and is processed, before processing of the wafer 21 the clamp 11 is demounted and a fluorine coated film 12 is formed on the surface of the clamp 11, and thereafter the wafer 21 is fixed to the stage 57 using the clamp 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing delamination of a deposit film in a semiconductor manufacturing apparatus such as a dry etching apparatus or a CVD apparatus used for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art A dry etching apparatus, a CVD apparatus or the like is used for manufacturing a semiconductor device. These devices generate reaction products during wafer processing. A dry etching apparatus will be described as an example. As shown in FIG. 3, the basic configuration of a parallel plate type plasma etching apparatus 51 as a dry etching apparatus is as follows.

An upper electrode 54 fixed by a tooled ring 53 is provided on the ceiling side inside a reaction chamber 52 for etching. The upper electrode 54 is provided with an introduction path 55 for introducing an etching gas into the reaction chamber 52 from the outside of the reaction chamber 52.

Further, a lower electrode 56 is provided at a position facing the upper electrode 54 on the bottom side inside the reaction chamber 52.
Is provided. The wafer 2 is placed on the lower electrode 56.
A stage 57 on which 1 is placed is formed. A clamp 11 that fixes the wafer 21 is provided on the side of the lower electrode 56. The clamp 11 is formed, for example, in an annular shape. Further, a high frequency power source 58 is connected to the lower electrode 56. An exhaust port 59 is provided in the reaction chamber 52 on the side of the periphery of the lower electrode 56. An exhaust device (not shown) is connected to the exhaust port 59.

In order to perform etching with the parallel plate type plasma etching apparatus 51 having the above structure, an etching gas is introduced into the reaction chamber 52 through the introduction passage 55. At that time, an exhaust device (not shown) connected to the exhaust port 59 is operated to adjust the pressure in the reaction chamber 52 to a predetermined pressure optimum for etching. Then, high frequency power is applied between the upper and lower electrodes 54 and 56 to generate plasma. Then, the film to be etched (not shown) formed on the wafer 21 is etched by the generated plasma.

[0006]

However, in the above etching, the etching gas component and the film to be etched are usually reacted to generate a reaction product. For example, the etching gas is argon (Ar) with a flow rate of 800 sccm.
And a mixed gas of carbon tetrafluoride (CF ₄ ) with a flow rate of 60 sccm and trifluoromethane (CHF ₃ ) with a flow rate of 60 sccm, and the pressure of the etching atmosphere is 133 Pa.
Then, the discharge was generated with an RF power of 800 W, and etching was performed. Then, a fluorocarbon-based reaction product is produced. Then, this reaction product adheres to the clamp, the inner wall of the reaction chamber, and the like.

[0007] The reaction product attached to the clamp peels off from the surface of the clamp when the integrated time of RF power discharge is less than 20 hours. In particular, since the clamp is operated for each wafer processing, the reaction product separated on the surface of the clamp easily drops on the wafer. As a result, the reaction products contaminate the wafer, resulting in a low yield.

According to the present invention, a reaction product generated during wafer processing in a semiconductor manufacturing apparatus is deposited, and the deposited product is peeled off to prevent contamination of the wafer from the peeled material. It is intended to provide a peeling prevention method.

[0009]

The present invention is a method for preventing peeling of a deposit film in a semiconductor manufacturing apparatus, which has been made to achieve the above object. That is, in a semiconductor manufacturing apparatus that fixes a wafer to a stage with a clamp and processes the wafer, the clamp is removed and a fluorine-based film is formed on the surface of the clamp before the wafer is processed. Deposition film peeling prevention method of fixing the wafer to the stage using.

[0010]

In the above method, in a semiconductor manufacturing apparatus for fixing a wafer to a stage by a clamp and performing the processing, the clamp is removed and a fluorine-based film is formed on the surface of the clamp before the processing of the wafer. After that, since the wafer is fixed to the stage by using the clamp, the reaction product generated in the processing of the wafer, particularly the fluorocarbon reaction product, reacts with the fluorine-based film formed on the surface of the clamp. Therefore, the reaction product is less likely to be peeled off from the clamp surface.

[0011]

EXAMPLE An example of the present invention will be described based on the method for preventing the deposition film from peeling as shown in FIG. The same components as those described in FIG. 3 are designated by the same reference numerals. As shown in (1) of FIG. 1, before performing wafer processing in a semiconductor manufacturing apparatus (not shown), the clamp 11 for fixing the wafer (21) to the stage (57) is removed from the semiconductor manufacturing apparatus,
For example, the fluorine-based coating 12 is formed on the surface of the clamp. The fluorine-based coating 12 is formed to have a film thickness of 100 μm, for example.

The above-mentioned fluorine-based coating 12 is shown in FIG.
As shown in FIG. 5, the surface of the clamp 11 is coated with a fluorine-based coating liquid 14 by, for example, a spray 13 to form the film.

Alternatively, as shown in FIG. 1 (3), the liquid tank 1
By immersing the clamp 11 in the fluorine-based coating liquid 16 in 5, the fluorine-based coating (12) is formed on the surface of the clamp 11.

Thereafter, as shown in (4) of FIG. 1, the clamp 11 on which the fluorine-based film 12 is formed is used to move to a stage 57 provided in a reaction chamber (not shown) of a semiconductor manufacturing apparatus. The wafer 21 is fixed.

A case will be described in which, after the fluorine-based coating 12 is formed on the surface of the clamp 11, the silicon oxide film is etched by plasma etching, for example. The etching gas has a flow rate of 800 scc, for example.
m of argon (Ar), carbon tetrafluoride (CF ₄ ) with a flow rate of 60 sccm, and trifluoromethane (CHF ₃ ) with a flow rate of 60 sccm were used, the etching atmosphere was stabilized at 133 Pa, and the RF power was 800 W. Etching was performed by generating discharge.

Then, a fluorocarbon-based reaction product 31 is produced by the etching reaction. Then, the reaction product 31 adheres to the surface of the clamp 11, the inner wall of the reaction chamber (not shown), and the like. At this time, as shown in FIG. 2, the reaction product 31 (fluorocarbon CF _{X in the} figure) reacts with the fluorine-based coating 12 (chain fluorocarbon in the figure) in the plasma atmosphere, It becomes the fluorocarbon film 32.
Since the fluorocarbon film 32 has good adhesiveness to the clamp (11), it is less likely to be peeled off than the surface of the clamp (11).

Therefore, the fluorocarbon-based film 32 attached to the clamp (11) activates the clamp (11) for each wafer processing, and the integrated time of the RF power discharge is 4 times.
No peeling occurs from the surface of the clamp (11) even if it exceeds 0 hours. Therefore, the wafer (21) is not contaminated by the peeled reaction product as in the conventional case, and the yield is improved.

The numerical values used in the description of the above embodiments are examples, and the values are not limited to them.

[0019]

As described above, according to the present invention,
Since the fluorine-based film is formed on the surface of the clamp, the reaction products deposited on the clamp do not peel off. As a result,
Since the wafer is not contaminated with the reaction products, the manufacturing yield can be improved. Since the frequency of exchanging the clamp can be reduced, the maintenance time of the semiconductor manufacturing apparatus can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a peeling prevention method according to an embodiment.

FIG. 2 is an explanatory diagram of a reaction.

FIG. 3 is a schematic configuration diagram of a conventional plasma etching apparatus.

[Explanation of symbols]

 11 Clamp 12 Fluorine-based coating 21 Wafer 31 Reaction product 32 Fluorocarbon-based film 57 Stage

Claims (1)

[Claims] 1. A method for preventing peeling of a deposit film adhered to a clamp in a semiconductor manufacturing apparatus for fixing a wafer to a stage with a clamp to process the wafer, the clamp being performed before performing the wafer processing in the semiconductor manufacturing apparatus. Is removed to form a fluorine-based film on the surface of the clamp, and then the wafer is fixed to the stage by using the clamp.