JPH0834184B2 - Electrode of plasma CVD device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma CVD apparatus for forming a thin film on a substrate, and more particularly to an electrode of the plasma CVD apparatus devised so as to improve the efficiency of the thin film manufacturing process.

2. Description of the Related Art A plasma CVD apparatus supplies high-frequency power to an electrode pair consisting of a high-frequency electrode and a substrate holder respectively arranged in the chamber and introduces a generated gas into the chamber so that a plasma is generated in the gap between the electrode pair. It is an apparatus that causes a discharge to form a thin film on a substrate placed on a substrate holder.

More specifically, the portion of the high-frequency electrode other than the substrate facing surface is substantially surrounded by the shield frame body of the conductor, and by setting this shield frame body to the same potential as the substrate holder, plasma is generated in the gap direction of the electrode pair. I was only trying to form.

By the way, in order to manufacture a substrate having the same optical and electrical characteristics, the film thickness of the thin film must be uniform. This requires stabilization of the high-frequency electric field across the surface of the substrate, that is, uniform plasma density, but it is difficult to do so. Was arranged so that the thin film could be made uniform.

Problems to be Solved by the Invention However, the above-mentioned conventional methods have the following problems. That is, from the viewpoint of improving the efficiency of the thin film manufacturing process, there is a demand to increase the effective area of the substrate or the supply amount of high-frequency power with respect to the electrode pair area, but in the case of the former, from the viewpoint of uniform thin film as described above. Be restricted. That is, the effective area of the substrate cannot be increased except for increasing the size of the chamber itself. In the latter case, plasma diverges from the open surface of the gap and the above-mentioned parallel electric field is disturbed, leading to non-uniformity of the thin film. Further, there is a disadvantage that the active species of the plasma adhere to and are contaminated with other than the substrate, for example, the observation window for observing the plasma state. Therefore, it is difficult to improve the efficiency of the thin film manufacturing process with the electrodes of the conventional plasma CVD apparatus more than the current level.

The present invention has been made in view of the above circumstances,
Plasma CVD that can improve efficiency of thin film manufacturing process
It is intended to provide an electrode for a device.

Means for Solving the Problems The electrode structure of the plasma CVD apparatus according to the present invention has the same potential as that of the substrate holder and surrounds the side surface of the high frequency electrode with a shield frame, and a projecting frame or a pair of shield frames. The groove frame, which is provided in the vicinity of the substrate periphery of the substrate holder and the substrate holder or the shield frame is moved so as to surround the open surface of the gap between the electrode pair, and the shield frame body and the frame body are brought close to each other. And a proximity moving means for moving. The proximity moving means is a means such as a cylinder.

When the frame portion and the shield frame body are brought close to each other by the proximity moving means to enclose the open surface of the gap in the electrode pair and plasma discharge is caused, the surrounding frame portion and the shield frame body The generated plasma is confined in the gap between the electrode pair due to the shield effect of keeping the same potential as that of the substrate holder.

Example FIG. 1 is a schematic sectional view of a chamber showing an example of an electrode of a plasma CVD apparatus according to the present invention, and FIG.
Is a simplified cross-sectional view when the shield frame body and the frame portion are close to each other, and FIG. 1B is a simplified cross-sectional view when the shield frame body and the frame portion are not close to each other.

The plasma CVD apparatus described here is an in-line type, and a high frequency electrode 20 having a generated gas introduction mechanism and a substrate holder 30 are arranged in the chamber 10 so as to face each other. These form an electrode pair. The high-frequency electrode 20 is fixed to the chamber 10 in an electrically insulated state, and the substrate holder 30 is a carrier truck on which a substrate 32 is placed. (Individually shown) are regulated by two rails 16 arranged in the lower part of the chamber 10 so that they can be moved in the front direction in the drawing. Further, this is made to have the same potential as the chamber 10 via the rail 16. Further, an exhaust port 13 for a vacuum exhaust system is provided on the side surface of the chamber 10, and a heating unit 17 for heating a substrate 32 is provided on the lower surface of the chamber 10 facing the high frequency electrode 20. When the plasma CVD apparatus is operated, high frequency power is supplied to the electrode pair, and at the same time, the generated gas is supplied through the gas introduction hole 2121 formed in the substrate facing surface of the high frequency electrode 20. A power supply for supplying high frequency power is not shown,
The reference potential side of the power source is connected to the chamber 10 and the substrate holder 30, and one output potential side is connected to the high frequency electrode 20.

More specifically, the high frequency electrode 20 is the electrode plate
An electrode portion 21 having two spaces separated by 211 and a lower electrode plate, and an electrode rod 22 welded to the central portion of the upper surface of the electrode portion 21.
It has and. Although not shown, a generated gas introduction pipe is provided inside the electrode rod 22. Then, the generated gas guided thereby passes through the gas intake port 113 formed at the upper center of the electrode portion 21, and then the gas introduction holes 2111 and 212 formed in the upper electrode plate 211 and the lower electrode plate 212, respectively.
1 are sequentially passed and introduced into the gap 70. Further, in order to stabilize the flow rate of the generated gas, the gas introduction holes 2111 and 2121 have a positional relationship in which the phases are shifted from each other. This high frequency electrode 20
Is attached via a shield frame body 40 welded to the chamber 10, the cylindrical body portion 41 of the shield frame body 40 is inserted into the opening 14 formed in the upper portion of the chamber 10 and welded, and the electrode The high frequency electrode 20 is fixed to the chamber 10 by inserting the rod 22 inside the cylindrical body portion 41 via the vacuum seal 15. In addition, the vacuum seal 15 should be made of an insulating material so that the chamber 10 and the high frequency electrode
20 and 20 are electrically insulated from each other. Details of the shield frame body 40 will be described later.

By the way, the plasma CVD apparatus conveys the substrate holder 30 to a predetermined position of the high-frequency electrode 20 and performs plasma discharge in this state.However, according to the invention, the plasma generated in the gap between the electrode pair is discharged in this space. The electrode of this plasma CVD apparatus will be described below.

This basic configuration includes a shield frame 40 that substantially surrounds the high-frequency electrode 20 other than the substrate facing side, and a protruding frame that forms a pair with the shield frame 40, which is provided near the periphery of the substrate 32 on the substrate holder 30. , The substrate holder 30 so as to surround the open surface of the gap 70.
And a cylinder 60 as a proximity moving means for moving the shield frame body 40 and the frame portion 50 close to each other. Both the shield frame body 40 and the frame portion 50 are conductors.

The shield frame body 40 includes a frame portion 50 that substantially surrounds the electrode portion 21 of the high-frequency electrode 20, and an electrode rod that is provided in the upper center part of the frame portion 50.
It comprises a cylindrical portion 41 which substantially surrounds 22. Further, although not necessarily required, a groove 421 is carved in the tip of the frame 50.
Also, as described above, the shield frame body is welded to each other.
40 and the chamber 10 have the same potential as the substrate holder 30.

 It has the same potential as the substrate holder 30.

The frame portion 50 has a shape that can be inserted into the groove 421, and the frame portion 5
The thickness of 0 is smaller than the width of the groove 421.

The cylinder 60 is the substrate holder 30 in the above-mentioned predetermined position.
Independently moving up and down a part of the rail 16 that supports
This is a mechanism for inserting the frame portion 50 into the groove 421 of the shield frame body 40, and the rail 16 is provided with three pieces each, six pieces in total (the central one is shown in the figure). More specifically, the cylinder 60 is a hydraulic cylinder provided in the outer lower portion of the chamber 10, and its rod 61 slides through the vacuum seal 62 to the opening 18 formed in the chamber 10. Has been done. Next, the operation of the cylinder 60 will be briefly described. FIG. 1 (a) shows the operating state of the cylinder 60 during plasma discharge, and FIG. 1 (b) shows the other operating state during normal operation. That is, during plasma discharge, the frame 50 is not completely inserted into the groove 421 of the cylinder 60, but a gap is formed between the frame 40 and the groove 421. This is to allow the generated gas taken in through the gas introduction hole 2121 to escape to the exhaust port 13, whereby the fresh generated gas is always supplied to the gap 70 between the electrode pairs.

The principle that plasma can be confined in the electrode of the plasma CVD apparatus configured as described above will be briefly described below.

When the shield frame body 40 and the frame portion 50 are brought close to each other as shown in FIG. 1A, the open surface of the gap 70 in the electrode pair is surrounded by the shield frame body 40 and the frame portion 50. Moreover, since the surrounding conductor has the same potential as that of the substrate holder 30, when a plasma discharge is generated in this state, the plasma is confined in the gap 70 due to its shielding effect.

In the present embodiment, the method of surrounding the open surface of the gap 70 has been described by inserting the frame portion 50, which is the protrusion, into the groove 421 formed in the end portion of the shield frame body 40. However, without being limited to this, for example, the shield frame body 40 and the frame portion 50 may be arranged so as to be displaced from each other, and may be arranged close to each other so as to surround the open surface of the gap 70. Furthermore, regarding the means of proximity movement,
Instead of moving the board holder 30 side, shield frame body
Of course, a method of moving the 40 side can be considered. in this case,
Other than using the substrate-supporting substrate holder, the positional relationship of the high-frequency electrode, the cylinder, and the like with respect to the chamber is changed, and similar effects can be obtained.

EFFECT OF THE INVENTION The electrode of the plasma CVD device according to the present invention is a plasma CVD device.
Since it is configured to lock the device in a pair of electrodes,
Even if the amount of high-frequency power is increased more than before, the nonuniformity of the thin film does not occur. Moreover, it is possible to increase the effective area of the substrate with respect to the electrode pair without drastically changing the existing equipment, and moreover, active species of plasma are less likely to adhere to the observation window or the like for observing the plasma state.
The number of times the chamber is opened for the purpose of removing this can also be reduced. Therefore, there is an effect that the efficiency of the thin film manufacturing process can be improved.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view of a chamber showing an embodiment of an electrode of a plasma CVD apparatus according to the present invention, and FIG. 1 (a) is a simplified view in a state where a shield frame body and a frame portion are close to each other. A cross-sectional view, FIG. 1 (b), is a simplified cross-sectional view in a state where the shield frame body and the frame portion are not close to each other. 10 ... Chamber, 20 ... High frequency electrode, 2121 ... Gas introduction hole, 30 ... Substrate holder, 32 ... Substrate, 40 ... Shield frame, 50 ... Frame part, 60 ... Cylinder, 70 ... gap,

Claims (1)

[Claims] 1. A substrate boulder to which a substrate is attached and an electrode pair composed of a high-frequency electrode facing the substrate boulder are arranged in a chamber, and high-frequency power is supplied to the electrode pair.
By introducing the generated gas through a gas introduction hole opened in the facing surface of the high-frequency electrode, in a plasma CVD apparatus for generating plasma in the gap between the electrode pair,
A shield frame body having the same potential as that of the substrate holder and surrounding the side surface side of the high-frequency electrode, and a projection frame or a groove frame paired with the shield frame body, which are provided in the vicinity of the substrate periphery of the substrate holder. Plasma CVD, comprising: a frame portion; and a proximity moving unit that moves the substrate holder or the shield frame to bring the shield frame body and the frame body close to each other so as to surround the open surface of the gap. Device electrodes.