JPH0517698B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to plasma CVD (Chemical Vapor
The present invention relates to an outer work holder that is attached to the outer periphery of a substrate to support the substrate when a thin film is formed on the substrate using a deposition method.

[Prior art] The conventional thin film formation method using plasma CVD is
As shown in FIG. 2, a substrate 3 to be processed is placed lying down on a substrate holder 2 in a vacuum reaction vessel 1, and an electrode 4 is placed above the substrate 3 so as to face the substrate holder 2. Applying high frequency power from a plasma power source 5 between the electrode 4 and the substrate holder 2,
Plasma is generated between the electrode 4 and the substrate holder 2, and a raw material gas is supplied into the plasma by a raw material gas supply means 6 consisting of a pipe to activate it, and a plasma is applied to the surface of the substrate 4 using a plasma CVD method. It formed a thin film.

In this case, in order to obtain a uniform film on the surface of the substrate 3, a ring-shaped recess 2A is provided on the surface of the substrate holder 2, and a protrusion 2B is provided in the center of the recess 2A, as shown in FIG. The substrate 3 was fitted into the recess 2A so that the film-forming surface of the substrate 3 was continuous with the surface of the substrate holder 2 without any step. This is because if this is not done, the plasma distribution will be non-uniform at the edge portions of the substrate 3 and the film thickness will change.
This tendency is particularly noticeable when the substrate 3 side is connected to the plasma power source 5.

In such a conventional thin film forming method using plasma CVD, a thin film can only be formed on one side (the upper side) of the substrate 3, so the process of forming a thin film on the other side must be performed again. , there was a problem with poor efficiency.

Therefore, as shown in FIGS. 4 and 5, the applicant placed a pair of raw material gas outlet electrodes 7 facing each other in the vacuum reaction vessel 1, and opened the outer periphery so that both sides could be exposed. A substrate 3 for processing supported by an outer work holder 8 is placed in the center between these raw material gas outflow electrodes 7, and the raw material gas is flowed out from both raw material gas outflow electrodes 7 toward both sides of the substrate 3. High frequency power is supplied from the plasma power supply 5 to the raw material gas outlet electrode 7 via the matching box 5A to generate plasma between the raw material gas outlet electrode 7 and both surfaces of the substrate 3. Recently, we proposed a plasma CVD device that simultaneously forms thin films on both sides of the substrate 3 by activating the raw material gas.

In this way, plasma can be generated on both sides of the substrate 3 by the substrate 3 and the raw material gas outlet electrodes 7 on both sides thereof, and the raw material gas from each raw material gas outlet electrode 7 can be transferred to the substrate 3. can be supplied to both sides of the substrate 3, and thin films can be formed on both sides of the substrate 3 at the same time.

[Problems to be Solved by the Invention] However, in the case of a plasma CVD apparatus that simultaneously forms films on both sides of the substrate 3 as shown in FIG. 4, when the film thickness distribution on the substrate 3 is measured, The results shown in FIG. 6 were obtained, and it was found that there was a problem in that the film thickness was thinner on the outer peripheral side of the substrate 3.

An object of the present invention is to provide an outer work holder that can easily form a film with a uniform thickness even on the outer circumferential side of the substrate when forming a film on both sides of the substrate at the same time.

[Means for Solving the Problems] To explain the configuration of the present invention for achieving the above object, the present invention provides a method for supporting the substrate by being attached to the outer periphery of the substrate with both sides of the substrate exposed. an annular outer work holder body; the outer work holder body is provided with a uniformly thick portion having a thickness substantially equal to the thickness of the substrate at least along the outer periphery of the substrate, surrounding the outer periphery of the substrate; It is characterized by being

[Function] When the outer work holder is used in this way, there is a uniformly thick part on the outer periphery of the board that is approximately the same thickness as the board, so it is easy to create a uniform thickness on both sides of the board, including the outer periphery. Film formation can be carried out in this manner.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1A to 1E, the outer work holder 8 of this embodiment is composed of a ring-shaped outer work holder body 9 and a mounting portion 10 for attaching the outer work holder body 9 to a support portion. has been done. The outer work holder main body 9 is divided into two parts, an upper half ring part 9A and a lower half ring part 9B, which are connected in a ring shape by a male joint part 8C and a female joint part 8D. It's summery. The inner periphery of such an outer work holder body 9 is provided with a substrate fitting groove 9E into which the outer periphery of the substrate 3 is fitted. Also,
The outer work holder main body 9 has a thickness of the substrate 3 (for example, 1.27
A uniformly thick portion 9F having a thickness (for example, 1.4 mm) approximately equal to mm) is provided surrounding the outer periphery of the substrate 3. The thickness of the uniformly thick portion 9E is preferably greater than or equal to the thickness of the substrate 3 and less than 125% of the thickness of the substrate 3. In addition, the uniform thickness portion 9
It is preferable that F be provided over 120% or more of the outer diameter of the substrate 3 from its outer periphery.

The uniform thickness portion 9F, which is 110% thicker (1.4 mm) than the thickness of the substrate 3 (1.27 mm), is the diameter of the substrate 3 (95 mm).
Using the outer work holder main body 9 provided over 126% (120 mmφ) of the substrate 3
When a film was simultaneously formed on both sides of the substrate by plasma CVD, it was possible to obtain a film thickness distribution of ±5% over 97% of the substrate 3.

In addition, if the uniform thickness portion 9F is smaller than 120% of the outer diameter of the substrate, or if the thickness of the outer work holder body 9 is larger than 125% of the thickness of the substrate 3, the film on the outer peripheral edge of the substrate 3 It was found that the thickness distribution did not fall within the range of ±5%.

The experimental results are shown in FIGS. 2 and 3. Second
The figure shows the range of the uniform thickness portion 9F of the outer work holder main body 9 (the outer diameter of the substrate 3 is taken as 100%).
and film thickness change at the peripheral edge of the substrate 3 (t-T)/T×
100(%) (where T is the film thickness at the radial center of the substrate 3, and t is the film thickness at a location 3 mm from the outer periphery of the substrate 3). As is clear from the figure, the uniform thickness portion 9F is equal to the diameter of the substrate 3.
It was found that when it exceeds 120%, the film thickness distribution does not fall within the range of ±5%.

FIG. 3 shows the thickness of the uniformly thick portion 9F of the outer work holder main body 9 (100% is when it is equal to the thickness of the substrate 3) and the change in the thickness of the peripheral portion of the substrate 3 (t- It shows the relationship between T)/T×100 (%). As is clear from the figure, the thickness of the uniformly thick portion 9F exceeds the thickness of the board 3 by 125
% or more, it was found that the film thickness distribution did not fall within the range of ±5%.

Note that the uniform thickness portion 9F may be provided over the entire outer work holder main body 9 if mechanical strength is not a problem.

[Effects of the Invention] As explained above, in the present invention, at least along the inner circumference of the outer work holder main body, a uniform thickness portion having a thickness approximately equal to the thickness of the substrate is provided over the entire circumference. , it is possible to improve the phenomenon that the thickness of the film becomes thinner on the outer peripheral side of the substrate, and it is possible to easily form a film with a uniform thickness on both sides of the substrate at the same time.

[Brief explanation of the drawing]

FIG. 1A is a front view of an embodiment of the outer work holder according to the present invention in an exploded state, FIG. 1B is a view taken along the line A-A in FIG. 1, and FIG. B
Figure 1D is a right side view of the upper half of Figure 1A, Figure 1E is a right side view of the lower half of Figure 1A,
Figure 2 is a diagram showing the relationship between the range of the uniformly thick part of the outer work holder body and the change in film thickness at the peripheral edge of the substrate. Figure 3 is a diagram showing the relationship between the thickness of the uniformly thick part of the outer work holder body and the substrate. Figure 4 is a diagram showing the relationship between film thickness changes at the periphery of conventional plasma.
A vertical cross-sectional view showing the schematic configuration of the CVD apparatus, FIG. 5 is a vertical cross-sectional view of the main part of the substrate holder in the case shown in FIG. 4, and FIG. 6 is a plasma CVD device proposed by the applicant.
FIG. 7 is a cross-sectional view of main parts showing the structure of the outer work holder of the plasma CVD device shown in FIG. 6. FIG. FIG. 1... Vacuum reaction vessel, 3... Substrate, 5... Plasma power source, 7... Raw material gas outflow electrode, 8... Outer work holder, 9... Outer work holder main body, 9E... Substrate fitting groove, 9F ...Uniform thickness part.

Claims (1)

[Claims] 1. An annular outer work holder main body is attached to the outer periphery of the substrate to support the substrate with both sides of the substrate exposed, and the outer work holder main body has a ring-shaped outer work holder main body that is attached to at least a portion along the outer periphery of the substrate. An outer work holder characterized in that a uniformly thick portion having a thickness substantially equal to the thickness of the substrate is provided surrounding the outer periphery of the substrate.