JP2003051485A - Coating silicon electrode plate for plasma etching - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating silicon electrode plate for plasma etching which has long utilization lifetime. SOLUTION: The coating silicon electrode plate for plasma etching is formed by forming a coating 11 of silicon carbide or diamond-like carbon, on at least the reverse surface 8 of a silicon electrode plate 2 for plasma etching, having a thin through-hole 5 along the thickness and the internal surface of the thin through-hole 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated silicon electrode plate used in a plasma etching apparatus and having a long service life.

[0002]

2. Description of the Related Art Generally, when manufacturing a semiconductor integrated circuit, it is necessary to etch a Si wafer.
It is well known that a plasma etching apparatus is used as an apparatus for etching an i-wafer. In order to etch a Si wafer using this plasma etching apparatus, as shown in FIG. 6, an electrode plate 2 and a pedestal 3 are provided at intervals in a vacuum container 1, and the pedestal 3 is placed on the pedestal 3. The Si wafer 4 is placed on the electrode plate 2 by the high frequency power source 6 while the etching gas 7 flows through the through holes 5 provided in the electrode plate 2 toward the Si wafer 4.
A high frequency voltage is applied between the frame 3 and the gantry 3. Then, the application of the high-frequency voltage causes the plasma 10 to be generated in the space between the electrode plate 2 and the pedestal 3, and the sputtering or physical reaction by the plasma 10 and the silicon-etching gas 7
The surface of the Si wafer 4 is etched by the chemical reaction caused by. The electrode plate 2 was sometimes made of carbon, but in recent years, silicon electrode plates mainly made of single crystal silicon, polycrystalline silicon or columnar crystal silicon have been used. When a Si wafer is plasma-etched using this silicon electrode plate, the through-holes 5 provided in the silicon electrode plate are formed as shown in FIG. 5, which is a partially enlarged sectional view of the silicon electrode plate. The plate is consumed as it spreads in a trumpet shape toward the surface facing the Si wafer and reaches the end of its life.

[0003]

In recent years, the demand for semiconductor integrated circuits has been rapidly increasing, and along with this, it has been required to extend the life of silicon electrode plates. However, silicon electrode plates having a long service life have not yet been obtained. Absent.

[0004]

Therefore, the present inventors have
As a result of research to develop a silicon electrode plate that can be used for a long time, in order to reduce the consumption of the silicon electrode plate, it was provided on the silicon electrode plate 2 as shown in the sectional view of FIG. In order to prevent the consumption of the through pores 5 and the lower surface 8, a coated silicon electrode plate has been developed in which a coating 11 made of silicon carbide or diamond-like carbon, which has less consumption than silicon, is formed on the entire lower surface 8.

However, the through-pores 5 of the coated silicon electrode plate having the coating 11 made of silicon carbide or diamond-like carbon are suppressed from being consumed by the coating 11 made of silicon carbide or diamond-like carbon to prolong the service life. However, when plasma etching is performed for a longer period of time, as shown in FIG. 3 (a) which is a partially enlarged cross-sectional view of the coated silicon electrode plate, the silicon electrode plate of the silicon electrode plate is left with the coating film 11 of silicon carbide or diamond-like carbon left. The wear progresses from the inner surface of the through-hole, and the inner surface of the through-hole becomes more worn, and the end of the silicon carbide or diamond-like carbon coating 11 forms the shelf 12. As the inner surface of the through hole further consumes,
As shown in the partially enlarged cross-sectional view of (b), the silicon carbide or diamond-like carbon shelf 12 has a particle size of:
The coarse particles 13 having a size of 0.3 μm or more are dropped and attached to the surface of the Si wafer. Such coarse particles 1
An unfavorable result was obtained such that the Si wafer having a large number of 3 attached thereto became defective and the yield of the plasma-etched Si wafer was reduced.

Therefore, the inventors of the present invention further researched to develop a silicon electrode plate that can be used for a longer period of time without causing coarse particles to adhere to the surface of the Si wafer even after plasma etching for a long period of time. It was As a result, (a) the lower surface 8 of the silicon electrode plate 2 was coated with the silicon carbide or diamond-like carbon coating 11, and the silicon carbide or diamond-like carbon coating 11 was also formed on the inner surfaces of the through pores 5. In the coated silicon electrode plate shown in the partially enlarged cross-sectional view of FIG. 1, the inner surface of the through pores 5 is not consumed even if plasma-etched for a long time, so that the silicon carbide or diamond-like carbon coating 11 does not drop, and thus the long-term Coarse particles are extremely unlikely to adhere to the Si wafer surface even by plasma etching. (B) A silicon carbide or diamond-like carbon coating 11 is further formed on the upper surface 9 of the coated silicon electrode plate shown in (a) above. The coated silicon electrode plate shown in the partially enlarged sectional view of FIG. Since the silicon carbide or diamond-like carbon coating 11 formed on the substrate has a higher thermal conductivity than silicon, it is possible to easily release the heat of the silicon electrode plate 2 and prolong the life. It was obtained.

The present invention has been made on the basis of the above research results. (1) In a silicon electrode plate for plasma etching in which through holes are provided parallel to the thickness direction, the silicon electrode plate A silicon electrode for plasma etching coated with a silicon carbide coating or a diamond-like carbon coating on the lower surface and the inner surface of the through-hole, (2) a silicon electrode for plasma etching in which the through-hole is provided parallel to the thickness direction. In the plate, a plasma-etched coated silicon electrode plate formed by forming a silicon carbide coating or a diamond-like carbon coating on the upper and lower surfaces of the silicon electrode plate and on the inner surfaces of the through pores.
It is characterized by

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A single crystal silicon ingot having a diameter of 280 mm is prepared, and this ingot is sliced with a diamond hand saw to a thickness of 5 mm to produce a single crystal silicon disc. A single crystal silicon electrode plate having an outer diameter of 280 mm and a thickness of 5 mm, in which through holes having an inner diameter of 0.5 mm were formed and both upper and lower surfaces were flat, was prepared.

Example 1 A silicon carbide coating film was formed on the lower surface and the inner surface of the through pores of the single crystal silicon electrode plate having an outer diameter of 280 mm thus produced by a usual chemical vapor deposition method to form a coated recon electrode plate of the present invention (hereinafter, referred to as The electrode plate of the present invention) 1 was produced.

Example 2 The electrode plate 2 of the present invention was prepared by forming a diamond-like carbon coating on the lower surface and the inner surface of the through pores of this single crystal silicon electrode plate having an outer diameter of 280 mm by a normal vapor phase synthesis method.
Was produced.

Example 3 The electrode plate 3 of the present invention was prepared by further forming a silicon carbide coating on the upper surface of the electrode plate 1 of the present invention manufactured in Example 1 by a normal chemical vapor deposition method.

Example 4 An electrode plate 4 of the present invention was prepared by further forming a diamond-like carbon coating on the upper surface of the electrode plate 2 of the present invention prepared in Example 2 by a normal vapor phase synthesis method.

Comparative Example 1 A comparatively coated recon electrode plate (hereinafter referred to as a comparative electrode plate) in which a silicon carbide coating was formed only on the lower surface of the previously prepared single crystal silicon electrode plate by ordinary chemical vapor deposition and vapor phase synthesis methods. 1 was produced.

Comparative Example 2 A comparative electrode plate 2 was prepared by forming a diamond-like carbon coating only on the lower surface of the previously prepared single crystal silicon electrode plate by a normal vapor phase synthesis method.

The electrode plates 1 to 1 of the present invention obtained in Examples 1 to 4
4 and the comparative electrode plates 1 and 2 obtained in Comparative Examples 1 and 2 are set in an etching apparatus, respectively, and a wafer on which a SiO ₂ layer has been previously formed by CVD is set in an etching apparatus. Chamber pressure: 10 ⁻¹ Torr, etching gas composition: 90 sccm CHF ₃ +4 sccmO ₂ +
Under the conditions of 150 sccm He, high frequency power: 2 kW, frequency: 20 kHz, plasma etching of the SiO ₂ layer on the wafer surface was performed, and adhered to the wafer surface after 10 hours, 100 hours, 200 hours, and 300 hours from the start of etching. The number of coarse particles having a diameter of 0.3 μm or more was measured, and the results are shown in Table 1.

[0016]

[Table 1]

From the results shown in Table 1, the electrode plate 1 of the present invention was obtained.
The number of coarse particles having a diameter of 0.3 μm or more attached to the wafer surface by performing plasma etching using Nos. 4 to 4 is almost absent even after performing plasma etching for 300 hours. Two
Plasma etching of the SiO ₂ layer on the surface of the wafer using
Twenty or more coarse particles of 0.3 μm or more are generated, and it can be seen that the electrode plates 1 to 4 of the present invention have a significantly longer life than the comparative electrode plates 1 and 2.

[0018]

As described above, since the coated silicon electrode plate of the present invention can be plasma-etched for a long time, it is possible to further mass-produce semiconductor integrated circuits by plasma etching. Can greatly contribute to the development of.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional explanatory view of a coated silicon electrode plate of the present invention.

FIG. 2 is a partial cross-sectional explanatory view of the coated silicon electrode plate of the present invention.

FIG. 3 is a cross-sectional explanatory view for explaining that coarse particles are likely to be generated in the comparative coated recon electrode plate.

FIG. 4 is a cross-sectional explanatory diagram of a comparative coated recon electrode plate.

FIG. 5 is a cross-sectional explanatory diagram for explaining a consumption pattern of through pores in a conventional single crystal recon electrode plate.

FIG. 6 is a cross-sectional explanatory view of a conventional plasma etching apparatus.

[Explanation of symbols]

1 vacuum container 2 electrode plates 3 mounts 4 Si wafer 5 Through pores 6 high frequency power supply 7 Plasma etching gas 8 Lower surface 9 Upper surface 10 Brasma 11 film 12 shelves 13 Coarse particles

Claims (3)

[Claims] 1. In a silicon electrode plate for plasma etching in which through holes are provided in parallel with a thickness direction, a silicon carbide film or a diamond-like carbon film is formed on a lower surface of the silicon electrode plate and an inner surface of the through holes. A coated silicon electrode plate for plasma etching characterized by the following. 2. A silicon electrode plate for plasma etching in which through holes are provided in parallel with a thickness direction, a silicon carbide film or a diamond-like carbon film is formed on both upper and lower surfaces of the silicon electrode plate and on the inner surfaces of the through holes. A coated silicon electrode plate for plasma etching, comprising: 3. The coated silicon electrode plate for plasma etching according to claim 1, wherein the silicon electrode plate is made of any one of single crystal silicon, polycrystalline silicon and columnar crystal silicon.