JPH10223613A - Formation of narrow through hole of silicon electrode plate for plasma etching - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form narrow through holes having no work modified layer through a silicon electrode plate by passing a wire through the holes and sliding the wire in the holes while paste containing abrasive grains is applied to the wire. SOLUTION: A silicon electrode plate 12 with narrow through holes 5 respectively having finished inside diameters of 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, and 0.8mm is manufactured by removing work damage layers 9 on the internal surfaces of the holes 5 by passing a wire 11 having a small diameter of 0.01mm through the holes 5 after the front end of the wire 11 is made thinner by etching and sliding the wire 11 in the holes 5 while paste 13 containing abrasive grains is applied to the wire 11, and then, completely removing the work modified layers 9 from the surface of the electrode plate 2 by removing the surface of the plate 2 to a depth of 2mm and smoothening the internal surfaces of the holes 5 by etching. Therefore, a silicon electrode plate for plasma etching having narrow through holes 5 containing no work modified layer can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming through-holes in a silicon electrode plate used in a plasma etching apparatus, and more particularly to a method for forming through-holes having a diameter of 0.08 to 0.9 mm without an affected layer. The present invention relates to a method for forming a hole.

[0002]

2. Description of the Related Art Generally, when manufacturing a semiconductor integrated circuit, it is necessary to etch a wafer. A plasma etching apparatus has recently been used as an apparatus for etching the wafer. In this plasma etching apparatus, for example, as shown in FIG. 7, an electrode plate 2 and a gantry 3 are provided at an interval in a vacuum vessel 1, and a wafer 4 is placed on the gantry 3, and an etching gas is 7
While flowing toward the wafer 4 through the through holes 5 provided in the electrode plate 2,
During which a high-frequency voltage can be applied.

The etching gas 7 supplied by the application of the high-frequency voltage turns into a plasma 10 in a space between the electrode plate 2 and the gantry 3, and the plasma 10 hits the wafer 4 to etch the surface of the wafer 4. As the electrode plate 2 used in this plasma etching apparatus, a silicon electrode plate 12 in which a plurality of through-holes 5 are formed as shown in a sectional view of FIG. 8 is used. The through-holes 5 were usually formed mechanically using a thin carbide drill or a diamond-coated drill.

[0004]

In recent years, the through-holes 5 formed in the silicon electrode plate are formed in the silicon electrode plate because the finer and larger the number of the through holes, the more preferable the flow of the etching gas becomes the steady flow. The through-pores 5 are required to be finer and more numerous than before. Such through-holes finer than before (diameter: 0.08 to 0.9 mm)
There is a limit in drilling a large number of through-pores having mechanical properties such as a thin carbide drill or a diamond-coated drill, and therefore, a laser machining method or an electric discharge machining method is used.

However, as shown in FIG. 1, the fine through-holes formed by using the laser machining method or the electric discharge machining method have a deteriorated machining layer 9 formed on the inner surface of the through-holes 5.
When a wafer is plasma-etched using a silicon electrode plate provided with through-holes having the processing-altered layer 9,
Many particles are generated, and therefore, as a method of forming fine through-pores in the silicon electrode plate, the laser machining method or the electric discharge machining method is not preferable. There is a need for a new method of forming holes.

[0006]

Means for Solving the Problems Accordingly, the present inventors have
From this point of view, the diameter of the inner surface without the affected layer: 0.0
As a result of researching to develop a method of forming through holes of 8 to 0.9 mm, fine through holes 5 formed by using a laser machining method or an electric discharge machining method as shown in FIG. Then, when the wire was slid while passing the wire 11 and applying paste containing abrasive grains to the wire, the damaged layer 9 formed by laser machining or electric discharge machining was removed. is there.

The present invention has been made based on this finding. (1) After forming through holes in a silicon electrode plate by laser machining or electric discharge machining, a wire is passed through the formed through holes. And a method for forming through-pores in a silicon electrode plate in which the wire is slid while applying a paste containing abrasive grains to the wire.

The starting end of the through-hole formed in the silicon electrode plate by the laser processing or the electric discharge processing generally has a mortar shape and a large diameter. If a wire having a diameter larger than the starting end of the through-hole is used, the damaged layer is completely removed.However, usually, the diameter of the through-hole formed by laser processing or electric discharge machining is larger than the diameter of the starting end of the through-hole. Since the wire having a small diameter is used, the deteriorated layer 9 formed at the beginning of the through-hole remains as shown in FIG. Therefore, after passing a wire through the through hole formed by laser machining or electric discharge machining on the silicon electrode plate, and sliding the wire back and forth while applying paste containing abrasive grains to this wire, after forming the through hole By removing the surface layer 14 of the silicon electrode plate shown in FIG. 4, the affected layer can be completely removed.

Accordingly, the present invention provides (2) grinding and removing the surface layer of the silicon electrode plate on the laser processing start side or the electric discharge machining start side of the silicon electrode plate having the through-holes formed by the method described in the above (1). A method for forming through-pores in a silicon electrode plate.

[0010] It is more preferable that the silicon electrode plate in which the through pores are formed by the method described in the above (1) or (2) is etched to smooth the roughness of the inner surface of the through pores. (3) A method of forming through-pores in a silicon electrode plate in which the silicon electrode plate in which through-pores are formed by the method described in (1) or (2) above is etched to smooth the inner surface of the through-holes. It is characterized by the following.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Example A defect-free single crystal silicon ingot having a diameter of a straight body of 400 mm and a total length of 1000 mm was prepared. hand,
A silicon electrode plate having a diameter of 350 mm and a plate thickness of 8 mm is prepared, and the silicon electrode plate is irradiated with a laser beam to form through holes having an inner diameter smaller than the finished through holes at 2.0 mm intervals. 4000 pieces have opened. On the other hand, a wire having a diameter 0.01 mm smaller than the inner diameter of the finished through-hole is prepared, and after the tip of this wire is thinned by etching, the tip of the wire is inserted into the through-pore,
By sliding the wire while applying a paste containing abrasive grains to the wire, the affected layer on the inner surface of the through-hole is removed, and the surface of the silicon electrode plate having the through-hole formed thereon has a thickness of 2 mm. After removal to completely remove the work-affected layer, the inner surface of the through-hole is smoothed by etching to make the inner diameters 0.2 mm and 0.3 mm, respectively.
mm, 0.4 mm, 0.5 mm, 0.6 mm and 0.
A silicon electrode plate having a finished through hole of 8 mm was produced.

The silicon electrode plate was set in a plasma etching apparatus, and the pressure in the chamber was 10 ^-1 Torr and the gas flow ratio was 90 sccm CHF ³ +4 sccm O ² +150 sc
cmHe, high-frequency power: 300 W, etching time: 1.0 min., diameter of SiO ₂ layer formed by CVD under the following conditions: 15
A 2 mm wafer was subjected to plasma etching, the number of particles having a diameter of 1 μm or more attached to the etched wafer surface was measured, and the etching uniformity of the wafer was measured. The results are shown in Table 1 and Table 1. The values are shown in the graphs of FIGS. In addition, the etching uniformity of the wafer is measured by measuring the depth: A of the deepest etched portion of the wafer, measuring the depth of the shallowest etched portion: B, and measuring the measured values of A and B. It is a value obtained by substituting into the equation of (AB) / B × 100 (%).

Conventional Example A laser beam was applied to the silicon electrode plate manufactured in the embodiment, and the inner diameter was 0.2 mm and the inner diameter was 0.2 mm without passing through a wire.
Finished through pores having 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm and 0.8 mm are formed at intervals of 2 mm.
00 silicon electrode plates were prepared. A deteriorated layer remains on the inner surface of the through-hole of the silicon electrode plate obtained by the conventional example, and plasma etching is performed using the silicon electrode plate having the deteriorated layer under the same conditions as in the embodiment. The number of particles having a diameter of 1 μm or more attached to the etched wafer surface was measured, and the etching uniformity of the wafer was measured. The results are shown in Table 1, and the values in Table 1 are shown in FIGS. Shown in the graph.

[0014]

[Table 1]

From the results shown in Table 1 and FIGS. 5 and 6, when the wafer is plasma-etched using the silicon electrode plate obtained in the embodiment of the present invention, the silicon electrode plate obtained in the conventional example is used. It can be seen that the number of particles adhering is much smaller than that of performing plasma etching on the wafer, and that the etching of the wafer becomes more uniform. In this example, the silicon electrode plate was manufactured from a single crystal silicon ingot, but the same result was obtained for a silicon electrode plate manufactured from a polycrystalline silicon ingot.

[0016]

As described above, according to the method of the present invention, it is possible to manufacture a silicon electrode plate for plasma etching having fine through-holes without a processing-altered layer, and to obtain an obtained processing-altered layer without a processing-altered layer. Since the silicon electrode plate has extremely few particles attached to the wafer surface during the plasma etching of the wafer and can uniformly etch the wafer, the occurrence of defective semiconductor integrated circuits due to plasma etching can be greatly reduced. It can greatly contribute to the development of the semiconductor device industry.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view for explaining a state in which through-pores are formed in a silicon electrode plate by laser processing or electric discharge processing.

FIG. 2 is an explanatory cross-sectional view for explaining a method of forming through-pores in a silicon electrode plate according to the present invention.

FIG. 3 is an explanatory cross-sectional view for explaining a method of forming through-holes in a silicon electrode plate of the present invention.

FIG. 4 is an explanatory cross-sectional view for explaining a method of forming through-pores in a silicon electrode plate of the present invention.

FIG. 5 is a graph showing the number of particles with respect to through pores of a silicon electrode plate.

FIG. 6 is a graph showing etching uniformity with respect to through pores of a silicon electrode plate.

FIG. 7 is an explanatory sectional view of a plasma etching apparatus.

FIG. 8 is a sectional view of a conventional silicon electrode plate for plasma etching.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Electrode plate 3 Mount 4 Wafer 5 Penetration pore 6 High frequency power supply 7 Plasma etching gas 9 Deterioration layer 10 Plasma 11 Wire 12 Silicon electrode plate 13 Paste containing abrasives 14 Surface layer

Claims (3)

[Claims] After a through hole is formed in a silicon electrode plate by laser machining or electric discharge machining, a wire is passed through the formed through hole, and the wire is slid while applying a paste containing abrasive grains to the wire. A method for forming through-pores in a silicon electrode plate, characterized in that the method comprises: 2. A silicon electrode plate having a through-hole formed by the method according to claim 1, wherein a surface layer of the silicon electrode plate on the laser irradiation side or the electric discharge machining start side is ground and removed. Method for forming through pores. 3. A through-hole of a silicon electrode plate, wherein the silicon electrode plate having the through-hole formed by the method according to claim 1 or 2 is etched to smooth the inner surface of the through-hole. Forming method.