JPH06151412A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To avoid the corrosion of the parts inside a chamber due to cleaning step by a method wherein the surfaces of the parts comprising stainless steel, silicon nitride, zirconia or copper arranged in the chamber are covered with an aluminum covering. CONSTITUTION:A heater unit 21 is formed of a heater presser 60, a heater main body 62 and a heater base 64. At this time, the heater presser 60 comprising silicon carbide in the higher thermal conductivity can effectively conduct the heat of the heater main body 62 to a heat equalizer sheet 22. On the other hand, the heater base 64 comprising the silicon nitride in the lower thermal conductivity can suppress the heat conduction to a heater unit base 66. Accordingly, the outer surfaces of the heater base 64 and the heater unit base are covered with an aluminum covering 68. In such a constitution, the corrosion of the parts inside a chamber can be avoided thereby enabling any foreign patter production due to the corrosion to be minimized.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plasma CVD apparatus. More specifically, the present invention relates to a plasma C which is less likely to corrode parts in the CVD chamber by the cleaning gas.
It relates to a VD device.

[0002]

2. Description of the Related Art In the manufacture of semiconductor ICs, there is a step of forming a thin film of silicon oxide or the like on the surface of a wafer.
A chemical vapor deposition method (CVD) is used as a method for forming a thin film. The CVD method is roughly classified into an atmospheric pressure method, a reduced pressure method and a plasma method. In recent ultra LSIs, high quality and highly accurate thin films are required for high integration, and it is difficult to meet the conventional atmospheric pressure or low pressure CVD method, and the plasma CVD method is drawing attention.

In this plasma CVD method, the reaction gas is glow-discharged in a vacuum to generate plasma and energy required for the reaction is obtained. The step coverage is good, and the step coverage is good. It has advantages such as strong film quality and excellent moisture resistance, and is also advantageous in that the film formation rate (deporate) is extremely fast compared to the depressurization method.

[0004]

When a silicon oxide film or a silicon nitride film is continuously formed by a plasma CVD apparatus, the reaction product adheres to the inner wall surface of the reaction furnace, electrodes, etc., and is peeled off when it exceeds a certain level. As a result, the plasma discharge is hindered, and the separated product becomes a foreign matter to contaminate the silicon wafer to be processed, resulting in deterioration of its quality. On the other hand, the inner wall of the reaction furnace, electrodes, etc. must be cleaned by plasma etching every time a proper number of wafers are processed.

As a method for cleaning the inside of the chamber of the plasma CVD apparatus, for example, a mixed gas of CF ₄ and O ₂ is used, and a high frequency voltage is applied to this gas for glow discharge, and foreign matter as a reaction product is removed by etching. It was a thing.

However, it has been recognized that when the film-cleaning cycle is repeated, the parts in the CVD chamber are corroded. In particular, parts made of materials such as stainless steel, silicon nitride and zirconia are susceptible to corrosion. When such components are corroded, the impedance in the chamber changes, the discharge becomes unstable, and the corrosive matter becomes foreign matter and adheres to the wafer surface, leading to a reduction in device yield.

Therefore, an object of the present invention is to provide a plasma C in which components in the chamber are less likely to be corroded by cleaning.
It is to provide a VD device.

[0008]

To achieve the above object, in the present invention, a heater for heating the aluminum soaking plate is provided which has an aluminum soaking plate constituting a ground substrate electrode on the upper surface. In a plasma CVD apparatus having a chamber having a susceptor having a susceptor and a high-frequency electrode facing the grounded substrate electrode on the susceptor, the components arranged in the chamber are made of stainless steel, silicon nitride, zirconia, or copper. Provided is a plasma CVD apparatus characterized in that an aluminum film is provided on the surface of the component.

[0009]

Among the components in the chamber of the plasma CVD apparatus, the ones which come into direct contact with the cleaning gas and are corroded by the cleaning process are made of stainless steel, silicon nitride, zirconia or copper. When aluminum coating is applied to the surface of parts made of these materials, CF ₄ ,
It has been discovered that even with a cleaning treatment with a fluorine-based cleaning gas such as C ₂ F ₆ , SF ₆ and NF ₃ , almost no corrosion occurs.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the plasma CVD apparatus of the present invention will be described in more detail below with reference to the drawings.

FIG. 1 shows the structure of an example of a plasma CVD apparatus 1 of the present invention. In the figure, chamber (reactor) 10
Is made airtight, and a susceptor 20 composed of a heater unit 21 and a heat equalizing plate 22 is fixedly mounted on the base 101, and this is used as a ground electrode. Nozzle 30 made of metal is attached to the cover plate 102 of the chamber.
Is fixed, and the disc-shaped shower electrode 40 made of aluminum is supported by the insulating ring 103 at the lower part thereof. A high frequency power supply 7 for applying a high frequency voltage to the shower electrode is provided. In the reaction process, the gate 51 of the loading / unloading path 50 provided on the side surface of the chamber 10 is opened, and the carriage 52
Then, the wafer 6 is loaded and placed on the soaking plate 22. After the gate is closed and the inside of the chamber is evacuated, the soaking plate is heated by the heater unit 21, and when the wafer placed on the soaking plate reaches a predetermined temperature, predetermined reaction gas and carrier gas are generated from the inlets 31 and 32. Inhaled nozzle part
The mixture is mixed inside 30 and sprayed from the spray hole 41 of the shower electrode. Here, when a high frequency voltage is applied to the shower electrode, the reaction gas is turned into plasma by glow discharge, and the reaction product is deposited on the surface of the wafer to form a thin film. The gas after the reaction is discharged to the outside from the exhaust port 104 through the path indicated by the arrow. By the above reaction process, reaction products adhere to the inner wall of the chamber (reactor), the shower electrode, the heat equalizing plate, etc., so when the processing of a predetermined number of wafers is completed, the supply of the reaction gas is stopped and the inlet 31 CF ₄ and O ₂ are introduced from the nozzles 32 and 32, mixed in the nozzle portion 30 and sprayed from the shower electrode, and the reaction products attached to the electrodes and the like are removed by etching.

FIG. 2 is a schematic enlarged sectional view of the susceptor 20 of the plasma CVD apparatus in FIG. The soaking plate 22 is made of aluminum. The heater unit 21 in FIG. 1 includes a heater retainer 60, a heater body 62, and a heater base 64. The heater holder 60 is preferably made of, for example, silicon carbide. Since silicon carbide has a high thermal conductivity, the heat of the heater body 62 is equalized by the heat equalizing plate 2.
2 can be effectively communicated. Heater body 62 A conventionally used resistance heating element such as a nichrome wire can be used. Other heating elements can of course be used. The heater base 64 is preferably made of, for example, silicon nitride. Since silicon nitride has a low thermal conductivity, it prevents heat from being transferred to the stainless steel heater unit cradle 66.

The silicon nitride heater base 64 and the stainless steel heater unit cradle 66 are susceptible to corrosion during the cleaning process with the fluorine-based gas. For this reason, the aluminum film 68 is applied to the outer surface. The thickness of the aluminum coating itself is not an essential requirement of the present invention. Generally, a sufficient corrosion prevention effect can be obtained with a film thickness of about 0.1 mm to 0.5 mm. If this film thickness is too thick, it may be deformed depending on the shape of the component, which is not preferable.

The method for forming the aluminum coating 68 is not particularly limited. Any method capable of forming an aluminum coating having a necessary and sufficient film thickness on the outer surface of a predetermined component can be used. For example, it can be formed by a method such as plasma spraying, CVD, sputtering, or plating.

In the embodiment shown in FIGS. 1 and 2, the components of the susceptor 20 are coated with aluminum, but other components in the chamber are made of stainless steel, silicon nitride, zirconia, copper or the like. If there is something, apply an aluminum coating on the outer surface as above,
Corrosion due to cleaning can be prevented.

[0016]

As described above, the parts in the chamber of the plasma CVD apparatus, which are made of stainless steel, silicon nitride, zirconia, copper, etc., are coated with an aluminum film on the outer surface thereof to clean them with a fluorine-based gas. Even if the treatment is performed, the corrosion of these parts can be prevented. As a result, the impedance in the chamber can be kept constant and discharge stability is maintained. In addition, since the generation of foreign matter due to corrosion is reduced, the manufacturing yield of wafers is improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an example of a plasma CVD apparatus of the present invention.

2 is a schematic partial enlarged cross-sectional view of a susceptor of the plasma CVD apparatus in FIG.

[Explanation of symbols]

 1 ... Plasma CVD apparatus 6 Wafer 7 High frequency power supply 10 Chamber (reactor) 101 Base 102 Cover plate 103 Insulation ring 104 Exhaust port 20 Susceptor 21 Heater unit 22 Soaking plate 30 Nozzle part 31, 32 Inlet 40 Shower electrode 41 Injection hole 50 Carry-in / carry-out path 51 Gate 52 Carriage 60 Heater holder 62 Heater body 64 Heater base 66 Heater base receiver 68 Aluminum coating

Claims (3)

[Claims] 1. A susceptor having an aluminum soaking plate constituting a ground substrate electrode on its upper surface and having a heater for heating the aluminum soaking plate, and a high frequency wave facing the ground substrate electrode on the susceptor. In a plasma CVD apparatus having a chamber having an electrode, an aluminum film is provided on a surface of a component arranged in the chamber, the component being made of stainless steel, silicon nitride, zirconia or copper. Plasma CVD apparatus. 2. The aluminum coating has a thickness of about 0.1 mm.
The plasma CVD apparatus according to claim 1, which is about 0.5 mm. 3. The plasma CVD apparatus according to claim 1, wherein the aluminum coating film is formed by a thermal spraying method.