JPS62199019A - Wafer treatment device - Google Patents

Abstract

PURPOSE:To enable the wafer treatment such as formation of CVD films with high uniformity by forming gas supply holes of an upper electrode so that a gas flow velocity on the circumference of a radius on which a substrate to be treated exists satisfies a specified relation. CONSTITUTION:In a wafer treatment device of parallel flat plate system comprising gas supply holes 17 on an upper electrode 16 opposed to a substrate to be treated, a distance between the processed substrate and the upper electrode is H, a radius of an i-th pitch circle from the center in the upper electrode is ri(i=1, 2, 3,...), the number and diameter of the gas supply holes 17 are ni and di respectively, and a coefficient is C. In this case, the gas supply holes 17 whose ri, ni and di are determined so that a gas flow velocity Wri on a circumference of a radius ri satisfies the equation in the Fig. is formed on the upper electrode 16 uniformly as a whole. By such a constitution, a flowing velocity of the gas supplied to a wafer through the gas supply holes 17 is always constant to a radius direction. Accordingly, the wafer treatment can be effected high uniformity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wafer processing apparatus, and particularly to a reaction gas supply apparatus in a dry etching apparatus, a CVD apparatus, etc. using a parallel plate method.

[Conventional technology]

Conventionally, in wafer processing equipment such as dry etching equipment, parallel plate methods that allow anisotropic etching have become mainstream in order to realize fine patterns on processed substrates (hereinafter referred to as wafers). .

Hereinafter, a conventional reaction gas supply device for a dry etching apparatus will be explained with reference to FIG. In the figure, 1 is a reaction chamber, and a reaction gas (hereinafter referred to as gas) 3 is introduced into the interior through a constant pressure chamber 4 from a gas inlet 2 provided on the top surface of the reaction chamber 1. be done. A gas exhaust port 5 is provided at a predetermined location on the periphery of the bottom surface of the reaction chamber 1 for exhausting the inside of the reaction chamber 1 to a predetermined pressure by means of an evacuation means (not shown) such as a Taliopong. Further, in the reaction chamber 1, an upper electrode 6 provided with a large number of gas supply holes (or porous material) 7 and a lower electrode 8 on which a wafer 9 is placed are arranged facing each other in the upper and lower positions, respectively. .

When processing the wafer 9, gas 3 is introduced from the gas inlet 2 into the constant pressure chamber 4, and then passes through the gas supply hole 7 with a constant predetermined pressure. Therefore, the gas 3 is uniformly supplied to the surface of the wafer 9 with the gas flow shown in the figure. Further, the gas 3a after the reaction with the wafer 9 is discharged from the gas exhaust port 5.
is discharged to the outside through the

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional example, the gas 3 introduced into the constant pressure chamber 4 is supplied to the wafer 9 through the uniformly formed gas supply port or the porous material 7. As shown, there is a problem in that the closer to the outer periphery the gas flow rate increases, causing variations in the etching rate. 6th
The figure is a typical example of the etching characteristics of plasma etching showing this situation, and the main processing conditions are: reactive gas; SF
a, reaction gas pressure; 0.2 Torr, x c;
St + Sin Na r lower electrode temperature; 30'C
, RF specific output is 300W. As is clear from the figure, the etching rate at the outer periphery of the wafer 9 is approximately 10% higher than at the center.

In the case of a CVD apparatus using the reaction gas supply device having the above configuration, the deposition rate of the CVD film increases at the outer periphery of the wafer.

Therefore, the present invention provides a wafer processing method that solves the problem that it is difficult to uniformly perform wafer processing such as dry etching and CVD film formation due to the non-uniformity of the gas flow rate supplied to the wafer. The purpose is to provide equipment.

[Means for solving problems]

The wafer processing apparatus according to the present invention has a wafer radius ri(i
=1.2.3...) gas flow velocity Wr i on each circumference
, that is, the total gas supply amount i within a circle with radius ri of the wafer Qri = R'1: , nR (lR = y, nRaR
” (nu: number of gas supply holes on the R-th pitch circumference from the center of the upper electrode, qn: gas supply amount from the gas supply hole, dR: hole diameter of the gas supply hole, C: coefficient) as HX2π
The amount divided by ri (H: distance between the wafer and the upper electrode, ri: radius of the i-th pitch circle from the center of the upper electrode) is
Wrt = Wrt = plus pitch circle radius ri,
Number of holes ni and hole diameter di t- on the pitch circumference with radius ri
, a large number of defined gas supply holes are formed in the upper electrode by lancing them as a whole.

[Operation] As described above, according to the present invention, the radius ri(i
The gas flow velocity on each circumference of =1.2.3...) is
Wr, m Wr, = ・= Wri x Pitch circle radius ri, the number of holes ni on the circumference of the radius ri, and the number of gas supply holes with the hole diameter di determined are formed in the upper electrode in a balanced manner. The flow rate of the gas supplied to the wafer through the gas supply hole is always constant in the radial direction.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 4. FIG. 1 is an explanatory diagram of the first embodiment of the present invention. In FIG. 1(a), 16 is an upper electrode, and 17 is a gas supply hole, four of which are equally spaced on the circumference of each pitch circle 18. It is formed. rl "" r@ indicates the radius of each pitch circle 18. Note that the gas supply holes 17 on the circumferences of the odd-numbered and even-numbered pitch circles 18 are formed at positions on the center line that form an angle of 45 degrees with each other, and are balanced throughout. Further, in the same figure (b), 12 is a gas inlet, 13 is a circumferential groove formed on the circumference of the pitch circle 18 including the gas supply hole 17, and 14 is a groove that covers the surface of the upper electrode 160. It is a porous material.

Here, based on the same figure (a), the first pitch circle radius ri (i=1.2.3...) from the center of the pitch circle 18 where the gas supply hole 17 is formed, the pitch circle radius ri
The relationship between the hole diameter di and the number of holes ni on the circumference will be explained. In this first embodiment, in order to gradually reduce the gas flow rate on the narrow surface of the wafer (not shown) from the center to the outer periphery,
The hole diameter di and the number of holes ni are kept constant as di=0.2(u) and re=4, respectively, and the pitch circle radius ri is set to the minimum pitch circle radius r+ (-12,5 m) as a numerical sequence 1.
, 2, 3, 4. ...Fnl...(n+=1.2.3
) is set to a multiple according to

As mentioned above, the total gas supply amount Qri within the circle with radius ri of the wafer, and the gas flow rate Wr on the circumference of the wafer with radius ri.
Each i is expressed as follows.

Qri WC left nBdB" - (1)
In the formula, H is the distance between the wafer and the upper electrode 16, C is the coefficient,
Also, l is a natural number. Four gas supply holes 17 are formed on the circumference of a pitch circle radius r in a circle having a radius rl. Therefore, the gas flow rate Q flowing out within a circle of radius r,
Gas flow r on the circumference of r+ and radius rl, (w25.
In the case of Ou+), the gas flow rate Qrt= C+
-8-(0,2)! Tona'), Qrf: Qr snow+
142, rl : r wealth = 1:2 yo F) Wr, =
Wr, is obtained and the flow velocities become equal. Similarly, Wrl
w Wr, = Wr, w −= Wr@, and if the pitch interval of the pitch circle radius ri is made smaller, the gas (
(not shown) is uniform over the entire wafer surface. Table 1 shows the relationship among the pitch circle radius rl, the hole diameter d1°, and the number of holes n1.

Table 1 Furthermore, the gas introduced from the gas inlet 12 is expanded in the circumferential direction by passing through the circumferential groove 13 and the porous material 14 via the gas supply hole 17, thereby increasing the gas flow velocity in the circumferential direction. Uniformity is also maintained sufficiently (see figure (b)).

Figure 2 shows plasma etching of a silicon nitride film (SlsNm) formed on a wafer using the reaction gas supply device with the above configuration and under the same etching conditions as in the conventional example described above. It shows the characteristics. As is clear from the figure, the etching rate remains constant regardless of the position within the wafer.

Next, a second embodiment will be explained based on FIG.

In this second embodiment, the gas supply hole 17 has a minimum pitch circle radius r4, a hole diameter peak on the circumference of the pitch circle radius r1, and the number n of holes as a reference, and the inner radius rl of each joint has a number sequence 1.
, 2, 3, 4. It is a multiple according to..., n,...,
The number of holes ni is the sequence 112' + 221231...1
2n-1,..., and similarly the pore diameter di is the number sequence 1,1
7ha7゜1/2, 1ρ,..., 1/de,...(n
The values are set as multiples according to the respective values (1, 2, 3, etc.). Further, these gas supply holes 17 are formed at equal intervals on the circumference of each pitch circle 18 and at positions that are balanced as a whole.

In this way, the number ni of the gas supply holes 17 is increased to a power according to the multiplier of the pitch circle radius ri, and the hole diameter di
By decreasing in inverse proportion to the square root of the number of holes ni, the gas flow velocity in the circumferential direction can be made more uniform. The fit 2 has the above-mentioned pitch circle radius rt and hole diameter di.
The relationship between the number of holes and the number of holes n1 is shown.

Table 2 Further, a third embodiment will be described based on FIG. 4.

In the case of this embodiment, in order to reduce the number of processing steps and improve the uniformity of the gas flow velocity in the circumferential direction, the hole diameters di are all constant (0, 50), and the holes on the circumference of each pitch circle 18 are The number ni is the number of holes n1 (=3
) as a reference, the sequence 1, 2, 22゜23,...
It is a multiple according to I 2n-11..., and each pitch circle radius ri is similarly the minimum pitch circle radius r+ (=12
．． 5rut) t-based, sequence 1, 3, 7
, 15 ,..., 2n-1゜..., 1.2.3...
). Further, these gas supply holes 17 are formed at equal intervals on the circumference of each pitch circle 1B, and at positions that are balanced overall. Table 3 summarizes the pitch circle radius ri, hole diameter di, and number of holes ni in the third embodiment.

Table 3 In addition, the circle 113 and the porous material 14 described in the first example
Of course, this can be similarly applied to the second and third embodiments.

(9) Although the reactive gas supply device of each of the above embodiments is applied to a dry etching device such as a glazma etching device, it is not applicable to CVD in which a reaction product film is formed on a wafer by supplying a reactive gas. It can be similarly applied to devices.

〔Effect of the invention〕

As described above in detail, according to the present invention, the upper part of a wafer processing apparatus such as a parallel plate type dry etching apparatus or CVD apparatus is The electrode is configured to have a pitch circle radius ri, a hole diameter di on the circumference of the pitch circle radius ri, and a large number of gas supply holes having a defined hole number ni in a balanced manner as a whole.

Therefore, there is an effect that wafer processing such as dry etching and CVD film formation can be performed with high uniformity.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the first embodiment of the present invention, Fig. 2 is an etching characteristic diagram of the first embodiment, Fig. 3 is an explanatory diagram of the second embodiment, and Fig. 4 is an explanatory diagram of the second embodiment. Explanatory diagram of the third embodiment, fifth
The figure is an explanatory diagram of a conventional example, and FIG. 6 is an etching characteristic diagram of the conventional example. 12... Gas inlet, 13... Circumferential groove, 14...
Porous material, 16... Upper electrode, 17... Gas supply hole, 18... Pitch circle. Ju 2 @ Stalk 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] (1) In a parallel plate type wafer processing apparatus having a gas supply hole for supplying a reactive gas to an upper electrode facing the arrangement position of the processed substrate, the distance between the processed substrate and the upper electrode is set to H. , the radius of the i-th pitch circle from the center in the upper electrode is ri (i=1, 2, 3...), and the number and diameter of the gas supply holes on the circumference of the pitch circle radius ri are respectively ni and d
When i and the coefficient are C, the gas flow velocity Wri on the circumference of the processed substrate with radius ri is ▲There are mathematical formulas, chemical formulas, tables, etc.▼ The above ri, ni and di are set to satisfy the following relational expression. A wafer processing apparatus characterized in that the predetermined gas supply holes are formed at positions that are balanced as a whole of the upper electrode. (2) The gas supply holes have a constant hole diameter di and a constant number of holes ni on the circumference of the pitch circle, and the pitch circle radius ri is set in the numerical sequence 1, 2, with r_1 as a reference.
3, 4,..., n,... (n=1, 2, 3...)
The wafer processing apparatus according to claim 1, characterized in that the wafer processing apparatus is formed by setting a multiple according to the following. (3) The gas supply hole has the pitch circle radius ri set to r_
Based on 1, the sequence 1, 2, 3, 4, ..., n, ...
...(n=1, 2, 3...), and the number of holes ni and the hole diameter d on the circumference of the pitch circle.
Let i be the sequence 1, 2^ with n_1 and d_1 as standards, respectively.
1, 2^2, 2^3,..., 2^n^-^1,...
and sequence 1, 1/√2, 1/2, 1/√2^3,...
, 1/√2^n^-^1,... (n=1, 2, 3...
The wafer processing apparatus according to claim 1, characterized in that the wafer processing apparatus is formed by setting multiples according to . (4) The gas supply hole has a constant hole diameter di on the circumference of the pitch circle, and the pitch circle radius ri and the number of holes ni are arranged in a numerical sequence based on r_1 and n_1, respectively.
, 2^1, 2^2, 2^3, ..., 2^n^-^1,
... and the sequence 1, 3, 7, 15, ..., 2^n-1
, . . . (n=1, 2, 3, . . . ), respectively.