JPH0527493Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a plasma CVD apparatus, and particularly relates to an improvement of the generated gas introduction mechanism.

BACKGROUND OF THE INVENTION Plasma CVD apparatuses are used as a thin film forming means in the semiconductor technology field and the like.

This plasma CVD apparatus normally includes a chamber, which is a vacuum container in which plasma is generated, and a substrate holder and an electrode unit that are disposed facing each other within the chamber.

On the other hand, there is a generated gas introduction mechanism as a mechanism for introducing generated gas into the chamber, and this generated gas introduction mechanism is configured to pass through a high frequency power block that supplies high frequency power.

That is, it is composed of an external introduction section connected to an external gas source and an internal introduction section communicating with the electrode unit side, that is, into the chamber.

In the prior art, this internal introduction is simply a relatively large diameter hollow hole drilled in the center of the high frequency power block.

Problems that the invention aims to solve When forming thin films using plasma CVD equipment, the most important thing is the stability of the discharge itself and its stable range, since the thin film must always be generated under constant conditions. It is the size of In practice, this refers to the stability of the high frequency power introduced into the chamber, and in terms of operation, it refers to the ease of adjustment of the so-called matching box.

However, with conventional plasma CVD equipment,
As mentioned above, since the single large-diameter hole drilled in the high-frequency power introduction block made of conductive material is itself used as the generated gas introduction hole, depending on the conditions, plasma discharge may enter the hole. There is sex. When the plasma discharge enters the generated gas introduction hole, the high frequency power increases rapidly there, making it difficult to adjust the matching box, and the plasma discharge cannot be performed stably. Furthermore, since the amount of high-frequency power consumed in the plasma discharge region increases, there is an economical disadvantage that this leads to power loss.

This idea was created against the above background, and it is a plasma that does not suffer from the various problems mentioned above.
The purpose is to provide CVD equipment.

Means for Solving the Problems The plasma CVD apparatus according to the present invention has a hollow electrode arranged parallel to the substrate holder in the chamber, and the electrode has a generated gas introduction hole formed on the opposite surface of the substrate holder. a high-frequency power block, which is a metal member for introducing high-frequency power into the electrode unit from outside the chamber and is brought into contact with the electrode unit through a hole formed in the chamber; and a high-frequency power block, the electrode unit, and the chamber. means for electrically insulating the chamber, a plurality of pores formed through the high frequency power block and communicating with the inner space of the electrode unit; It is characterized by comprising a means for introducing the produced gas into the chamber sequentially through the space and the produced gas introduction hole.

Operation The generated gas sent from outside the chamber is introduced into the chamber through the plurality of pores formed in the high frequency power block, the internal space of the electrode unit, and the generated gas introduction hole in sequence. In this state, when high frequency power is applied between the chamber and the high frequency power block, plasma discharge occurs between the substrate holder and the electrode unit. The pressure inside the pores formed in the RF power block is higher than inside the chamber. Moreover, inside the pore, the produced gas molecules collide with the inner wall of the pore (which has the same potential as the high-frequency power block) more frequently than the produced gas molecules collide with each other. Therefore, conditions for molecular flow are ensured inside the plurality of pores through which the generated gas flows, making it difficult for plasma discharge to occur in this portion.

Embodiment In the figure, 10 is a chamber, and this chamber 10 is provided with an exhaust port 11 and a generated gas introduction mechanism 100, which will be described later, and a cooling pipe (not shown) surrounds the outer periphery of the chamber.

Inside the chamber 10, a substrate holder 20 having a built-in heater and an electrode unit 30 are disposed facing each other. The electrode unit 30 includes an upper electrode plate 31 and a lower electrode plate 32, and both electrode plates have a plurality of generated gas introduction holes 311 and 3 having different phases from each other.
21, respectively.

Specifically, the shape of the upper electrode plate 31 is a disk, and a plurality of spacers 312 are welded to the lower part of the periphery in order to maintain a constant distance from the lower electrode plate 32, and the spacers 312 are screwed. A hole is provided. The lower electrode plate 32 is simply formed into a disk shape. Reference numeral 40 denotes a frame made of metal and formed into a substantially thin plate shape, and this frame 40 has spacers 41 formed on its inner peripheral surface at positions corresponding to the spacers 312. Furthermore frame 40
As shown in FIG. 2, a screw hole 42 for fixing to the high frequency power block 50 is drilled in the bottom plate of the high frequency power block 50.
For example, eight pores 43 are provided on the same circumference, communicating with the plurality of pores 51 provided on the same circumference. In addition,
The high frequency power block 50 is adapted to have a high frequency cable from a matching box applied to a terminal 52.

An electrode holder 60 made of an insulating material and having a large-diameter opening 63 at its center is provided on the outer periphery of the frame 40 so as to surround the frame 40 like a double plate. The outside of the electrode holder 60 is grounded to the base of the chamber 10 with a bolt 62 via a metal bracket 61.

That is, the upper electrode plate 31 and the lower electrode plate 32 are arranged in parallel by the frame 40 as shown in the figure.
The frame 40 is attached to the bottom plate of the chamber 10 while being surrounded by the electrode holder 60.

70 is an insulating spacer, and this insulating spacer 70, together with the insulating bushing 80, is provided to insulate the high frequency power block 50 from the chamber 10. That is, the insulating spacer 70
together with the high frequency power block 50, the bolt 7
1. It is airtightly fixed to the bottom plate of the chamber 10 from the outside by an insulating bushing 72. In addition,
The insulating block 90 is interposed between the flange 111 of the external introduction part 110 and the high frequency power block 50, and the bolts 93 and seals 94 hermetically connect the two.

100 is a generated gas introduction mechanism, and this generated gas introduction mechanism 100 includes an external introduction section 110 and an internal introduction section 120 that communicates with the external introduction section 110.

The external inlet 110 is also connected to a source of product gas with a tightening screw as shown.

The internal introduction part 120 has a plurality of pores 43 cut out in the frame 40 and a high frequency power block 50.
A plurality of pores 51 cut out in the insulating block 9
It includes a plurality of pores 91 hollowed out within 0. These pores communicate with each other to form an internal introduction section 120, and the internal introduction section 120 communicates with the external introduction section 110.

In one embodiment, each of the pores has a diameter of about 0.8 mm, and is formed concentrically.

The operation of the plasma CVD apparatus configured in this way will be explained below.

Set the desired substrate on the substrate holder 20,
Close the generated gas introduction mechanism 100 and open the chamber 10.
The interior is evacuated to a predetermined degree of vacuum using an exhaust device (not shown).

Next, the lid of the generated gas introduction mechanism 100 is opened, a needle valve (not shown) is adjusted, and the main valve of the exhaust system is slightly opened to set the generated gas flowing into the chamber 10 to a predetermined value.

Plasma is generated between the substrate holder 20 and the electrode unit 30 by applying high frequency power and adjusting the matching box. Due to the generation of plasma, a thin film is deposited on the substrate.

As a result of conducting various experiments using the plasma CVD apparatus having the structure described above, it was found that no plasma discharge was generated in the internal introduction part 120 formed in the high frequency power block 50, unlike when using the conventional apparatus. It was confirmed that plasma did not enter this area. Therefore, the plasma discharge is stabilized,
The high frequency power does not increase suddenly, and the adjustment of the matching box becomes very easy. In addition, the loss of high frequency power consumed in the plasma discharge region was also reduced.

Effects of the invention In the case of the plasma CVD apparatus according to the invention, the structure is such that plasma discharge is difficult to occur in the portions of the plurality of pores through which the generated gas flows, so that there is a gap between the substrate holder and the electrode unit. The stability of plasma discharge can be improved. Then,
Not only is it easier to adjust the matching box, but the loss of high frequency power is also reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of one embodiment of this invention, and FIG. 2 is a detailed sectional view of the internal introduction part and electrode unit in FIG. 1. 10...Chamber, 20...Substrate holder, 30
... Electrode unit, 50 ... High frequency power block, 100 ... Generated gas introduction mechanism, 110 ...
External introduction part, 120...internal introduction part.

Claims (1)

[Scope of utility model registration request] A substrate holder provided in the chamber, an electrode unit which is a hollow electrode arranged parallel to the substrate holder in the chamber and has a generated gas introduction hole formed on the opposite surface of the substrate holder, and an electrode unit that is inserted from outside the chamber. A metal member for introducing high frequency power into the chamber, the high frequency power block being brought into contact with the electrode unit through a hole formed in the chamber, and means for electrically insulating the high frequency power block, the electrode unit, and the chamber. , a plurality of pores are formed through the high frequency power block and communicate with the inner space of the electrode unit, and the produced gas is introduced from outside the chamber through the plurality of pores, the inner space of the electrode unit, and the produced gas introduction hole in sequence. and a means for introducing the plasma into the chamber through the plasma.
CVD equipment.