JPH04151826A - Dry etching device for oxide film - Google Patents

Abstract

PURPOSE:To lessen the waste of components due to an etching and to contrive the prolongation of the lives of the components by a method wherein the components using a silicon layer as their surfaces are provided in a reaction chamber. CONSTITUTION:Components using a silicon layer as their surfaces are provided in a reaction chamber 1. For example, a coated protective layer 7, such as the silicon layer or the like, is provided on the surface of a wafer press 2. Parts, which are exposed to plasma, of the components constituting the interior of the chamber 1 are prevented from being hardly etched by performing a dry etching, in which a condition that the selection ratio of a wafer 3 to an oxide film is increased is used. Thereby, the deterioration of the lives of the components due to an etching can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an oxide film dry etching apparatus for etching a wafer.

Conventional technology Semiconductor manufacturing processes involve repeating a basic cycle of forming a resist film, forming a resist pattern, etching to mask the resist, and removing the resist. Therefore, try etching is the mainstream.

In principle, dry etching technology uses reactive gases, radicals, active ions, inactive ions, etc. as reactive excitation sources to selectively remove constituent materials of semiconductor substrates, such as polycrystalline SL, crystalline SS, and 0□. Etch and process to specified dimensions. Specifically, are there any etching methods such as gas etching, plasma etching, reactive ion etching, sputter etching, or ion beam etching?Among these etching methods, means using plasma are the most commonly used. There is. Reactive ion etching also uses plasma generated by high frequency discharge.Hereinafter, a conventional oxide film dry etching apparatus using reactive ion etching will be explained with reference to FIG.

FIG. 2 is a cross-sectional view of a conventional parallel plate RIE (reactive ion etching) oxide film dry etching apparatus, mainly showing the wafer holding area and its vicinity.

In order to carry out dry etching, a wafer 3 to be etched is fixed to a lower electrode 4 using a wafer holder 2 as a support part for the object to be etched in a reaction chamber I as a space in which an etching gas is introduced and plasma is generated. For example, CHF3, which is a fluoride-based gas, is introduced as an etching gas at a predetermined pressure, and a high frequency power source (RF constant power source 5) is applied between the lower electrode 4 and the ground.At this time, the upper electrode 6 and the lower electrode connected to the ground are Since the wafer 3 to be etched and the lower electrode 4 supporting it are negatively biased, plasma ions are generated vertically from the upper electrode 6 toward the lower electrode 4. It's coming in.

When ions accelerated by a drop in the cathode potential near the upper surface of the lower electrode 4 are incident perpendicularly to the wafer 3, the wafer 3 is etched by a physical sputtering effect. At this time, the sputtering is performed not only on the oxide film of the wafer 3 to be etched, but also on the wafer holder 2 and other parts constituting the inside of the reaction chamber 1, and the amount etched is smaller than the amount originally etched. The selection ratio is determined by the etching rate, which is the ratio of the etching rate of the oxide film to be etched and the material constituting the part that does not like etching.

However, in the above configuration, the parts of the reaction chamber 1 are exposed to the plasma, so if the material of the parts of the reaction chamber 1 is stainless steel, for example, this is etched and the parts of the reaction chamber 1 are exposed to the plasma. There was a problem with heavy metal contamination inside the plant. Furthermore, if parts such as the wafer holder 2 in the reaction chamber 1 are made of quartz, the surface of these parts will be etched and worn out, and the roughened surface will become a source of unnecessary particles, requiring frequent parts replacement. The problem was that it was not necessary.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an oxide film dry etching apparatus having parts that are easy to manufacture and have a long life.

Means for Solving the Problem In order to solve this problem, the oxide film dry etching apparatus of the present invention is characterized in that a component having a silicon surface is provided in the reaction chamber.

According to these configurations of the present invention, by performing dry etching using conditions that increase the selectivity with respect to the oxide film of the wafer, the parts of the parts constituting the interior of the reaction chamber that are exposed to plasma can be In this case, this part is not etched, so the wear and tear of the parts is minimal.
In addition, since the surface is not roughened, the generation of unnecessary particles can be reduced.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an oxide film dry etching apparatus showing an example in which the present invention is implemented around a wafer holder in a parallel plate RTE. Components having the same functions as those in FIG. 2 showing a conventional example are designated by the same reference numerals. I'm wearing it.

In FIG. 1, 2 is a wafer holder which is a molded part made of quartz, 7 is a protective layer such as silicon coated on the surface of the wafer holder 2, ■ is a reaction chamber, 6 is an upper electrode,
4 is a lower electrode, and 5 is an RF constant power source applied between the lower electrode 4 and the upper electrode 6. The reason why a quartz molded part is used as the wafer holder 2 is that it can be highly purified, is easy to mold, and is difficult to peel off when silicon 7 is coated on its surface. In this embodiment, only the wafer 1 and the presser foot 2 that are directly hit by the plasma are coated with silicon 7, but this is because the parts that are directly hit by the plasma are most likely to wear out and become a source of particles. In addition, in this embodiment, the silicon 7 on the surface of the wafer holder 2 is grown by CVD (chemical vapor deposition).
A protective layer of polysilicon or amorphous silicon was formed to a thickness of about 100 μm. This is because it can be easily formed using conventional equipment. Of course, the film thickness of the silicon 7 may be set arbitrarily.

In the oxide film dry etching apparatus of this embodiment constructed as described above, the case where the oxide film of the wafer 3 is etched will be described below.

The oxide film dry etching apparatus having the above configuration etches the oxide film on the wafer 3 using, for example, CH as an etching gas.
Etching is performed by applying power of 350 W from the RF power source 6 with F3 for 50 seconds and 0□ for 3 seconds and an etching pressure of 15 Pa.

Under these conditions, the selectivity ratio, which indicates the ratio of the etching speed of the oxide film to silicon, is approximately 10. Therefore, by making the surface of the wafer holder 2 silicon as described in ``2'' below, the consumption of the wafer holder 2 should be reduced by etching. I/1 compared to oxide film
It can be suppressed to 0.

By making the surface of the part exposed to plasma, the wafer holder 2 in this embodiment, silicon, the life of the wafer holder 2 can be extended about 10 times compared to when the surface is not silicon.

In this embodiment, a molded quartz part may be used as the wafer presser 2, or other materials may be used.

Further, in this embodiment, only the wafer holder 2 has a silicon surface, and it goes without saying that the surfaces of other parts of the reaction chamber may also be made of silicon.

Further, in this embodiment, the silicon 7 on the surface is made of polysilicon or amorphous silicon by CVD method, but it may be formed by other methods such as sputtering method.
Furthermore, by making crystalline silicon through heat treatment, the surface becomes less rough, so even more effects can be obtained.

Furthermore, in this embodiment, the oxide film dry etching apparatus was applied to a parallel plate RIE apparatus, or other oxidation apparatuses such as a triode type RIE apparatus, a magnetron RIE apparatus, an ECR etching apparatus, a down flow type CDE (chemical dry etching) apparatus, etc. A similar effect can be obtained when applied to a film dry etching device.

Effects of the Invention As described above, according to the oxide film dry etching apparatus according to claim 1 of the present invention, since parts having silicon surfaces are provided in the reaction chamber, the wear of the parts due to etching is reduced, and the parts It can significantly extend lifespan.

Furthermore, according to the oxide film dry etching apparatus according to claim 2, in order to siliconize the surfaces of the components in the reaction chamber,
This can be easily done by coating with polysilicon or amorphous silicon, and can prevent deterioration of the life of the component due to etching. Also, since such coatings are easy to apply, the manufacturing of the component is facilitated.

Further, according to the oxide film dry etching apparatus according to claim 3, by using quartz as the material of the parts in the reaction chamber,
It becomes possible to improve the purity of the parts.

Furthermore, the manufacturing of the parts is facilitated by the ease of processing and molding, and coating with silicone makes it difficult for the silicone to peel off, extending the life of the parts in the reaction chamber.

Further, according to the oxide film dry etching apparatus according to claim 4, since the object to be etched support part is provided with a part whose surface is made of silicon, the object to be etched which is most prone to wear when the surface is not made of silicon. This reduces the amount of wear and tear on the support parts and can extend their lifespan.

According to the oxide film dry etching apparatus according to the fifth aspect, since a protective layer made of crystallized polysilicon or amorphous silicon is provided on the surface of the component in the reaction chamber, the roughness of the surface of the component is reduced. This can prevent the generation of unnecessary particles.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an oxide film dry etching apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional oxide film dry etching apparatus. DESCRIPTION OF SYMBOLS 1... Reaction chamber, 2... Wafer holder [etched object support component], 7... Silicon [protective layer].

Claims (1)

[Scope of Claims] 1. An oxide film dry etching apparatus characterized in that a reaction chamber is provided with a component whose surface is silicon. 2. The oxide film dry etching apparatus according to claim 1, wherein the surfaces of the components in the reaction chamber are coated with polysilicon or amorphous silicon. 3. The oxide film dry etching apparatus according to claims 1 and 2, wherein the material of the parts in the reaction chamber is quartz. 4. The oxide film dry etching apparatus according to claim 1, characterized in that a part supporting the object to be etched in the reaction chamber includes a part having a silicon surface. 5. Claim 2, wherein a protective layer made of crystallized polysilicon or amorphous silicon is provided on the surface of the component in the reaction chamber.
The oxide film dry etching apparatus described above.