JPH06151411A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To evenly sustain the film quality and film thickness distribution of a thin film formed on a wafer surface by a method wherein a gas dispersing sheet having multiple through holes are arranged adjacently to an aluminum- made bored sheet. CONSTITUTION:A gas dispersing sheet 60 is arranged this side of a shower electrode 40. Next, a reactive gas led in by an inlet is mixed in the first gas reservoir 62 further to be led in the second gas reservoir 66 passing through holes 64 made in the dispersing sheet 60. Next, the reactive gas is mixed again in the second gas reservoir 66 to be fed to the wafer surface passing the other through holes 41 made in the shower electrode 40. In such a constitution, two gas reservoirs can be arranged so that the uneven feed of the reactive gas due to the fluctuation in the production requirements may be avoided thereby enabling the evenness in the film quality and film thickness on wafer surface of a produced CVD film to be enhanced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plasma CVD apparatus. More specifically, the present invention relates to a plasma CVD apparatus capable of uniformizing the film quality and film thickness distribution within the wafer surface.

[0002]

2. Description of the Related Art In the manufacture of semiconductor ICs, there is a step of forming a thin film of silicon oxide or the like on the surface of a wafer.
A chemical vapor deposition method (CVD) is used as a method for forming a thin film. The CVD method is roughly classified into an atmospheric pressure method, a reduced pressure method and a plasma method. In recent ultra LSIs, high quality and highly accurate thin films are required for high integration, and it is difficult to meet the conventional atmospheric pressure or low pressure CVD method, and the plasma CVD method is drawing attention.

In this plasma CVD method, the reaction gas is glow-discharged in a vacuum to generate plasma and energy required for the reaction is obtained. The step coverage is good, and the step coverage is good. It has advantages such as strong film quality and excellent moisture resistance, and is also advantageous in that the film formation rate (deporate) is extremely fast compared to the depressurization method.

[0004]

FIG. 1 shows an example of a conventional plasma CVD apparatus used. In the figure, the chamber (reactor) 10 is made airtight and its base
A susceptor 20 including a heater unit 21 and a heat equalizing plate 22 is fixedly installed on 101, and this is used as a ground electrode. The metal nozzle part 30 is fixed to the cover plate 102 of the chamber, and the aluminum disc-shaped shower electrode 40 is attached to the lower part of the nozzle part 30 with the insulating ring 103
Supported by. A high frequency power supply 7 for applying a high frequency voltage to the shower electrode is provided. In the reaction process, the gate 51 of the loading / unloading path 50 provided on the side surface of the chamber 10 is opened, and the wafer 6 is loaded by the carriage 52 and placed on the heat equalizing plate 22. After the gate is closed and the inside of the chamber is evacuated, the soaking plate is heated by the heater unit 21, and when the wafer mounted on the soaking plate reaches a predetermined temperature, predetermined reaction gas and carrier gas are supplied from the inlets 31 and 32. It is sucked, mixed inside the nozzle portion 30, and ejected from the ejection hole 41 of the shower electrode. Here, when a high frequency voltage is applied to the shower electrode, the reaction gas is turned into plasma by glow discharge, and the product of the reaction is deposited on the surface of the wafer to form a thin film. The gas after the reaction is discharged to the outside from the exhaust port 104 through the path indicated by the arrow.

In the conventional shower electrode, changes in production conditions (for example, gas conditions, pressure, high frequency output, temperature, electrode interval, etc.) appear as changes in the reaction gas supply pattern directly on the wafer surface. For this reason, the film quality and film thickness distribution of the thin film formed on the wafer surface also fluctuate, which causes a reduction in product yield.

Therefore, an object of the present invention is to provide a plasma CVD apparatus capable of maintaining uniform film quality and film thickness distribution of a thin film formed on a wafer surface, even if production conditions change. .

[0007]

To achieve the above object, in the present invention, a heater for heating the aluminum soaking plate is provided which has an aluminum soaking plate constituting a ground substrate electrode on the upper surface. In a plasma CVD apparatus having a chamber having a susceptor having a hole and a high frequency electrode made of an aluminum perforated plate facing the ground substrate electrode on the susceptor, a number of through holes are provided adjacent to the aluminum perforated plate There is provided a plasma CVD apparatus characterized in that a gas dispersion plate having the above is provided.

[0008]

In the plasma CVD apparatus of the present invention, since another gas dispersion plate is disposed in front of the shower electrode, two reaction gas reservoirs are formed and the dispersibility of the gas on the wafer is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the plasma CVD apparatus of the present invention will be described in more detail below with reference to the drawings.

FIG. 2 is a partial sectional view of a novel high frequency electrode according to the present invention. As shown in the figure, a gas dispersion plate 60 is arranged in front of the shower electrode 40. As a result, the reaction gases introduced from the inlets 31 and 32 in FIG. 1 are mixed in the first gas pool 62 and enter the second gas pool 66 through the through holes 64 formed in the gas dispersion plate 60. Here, they are mixed again and supplied to the upper surface of the wafer through the through holes 41 of the shower electrode 40. In this way, by having two gas reservoirs,
The non-uniform supply of the reaction gas due to the fluctuation of the generation condition is prevented, and the uniformity of the film quality and the film thickness of the generated CVD film on the wafer surface is improved.

The material itself of the gas dispersion plate 60 is not particularly limited. For example, in addition to metal materials such as aluminum and alumina, inorganic materials such as glass and ceramics can be used. The thickness of the gas dispersion plate is not particularly limited. The thickness may be any thickness sufficient for dispersing the gas. The number of through holes to be opened is also not particularly limited. In order to enhance the gas dispersion effect, it is preferable that the through holes are formed at positions that do not coincide with the through holes formed in the lower shower electrode.

[0012]

As described above, in the high frequency electrode in the plasma CVD apparatus of the present invention, another perforated gas dispersion plate is inserted adjacent to the shower electrode facing the wafer. Therefore, the reaction gas that has passed through the nozzle from the gas inlet is first diffusively mixed by the gas dispersion plate, and then further diffusively mixed in the space between the gas dispersion plate and the shower electrode and supplied to the upper surface of the wafer. It Therefore, the gas supply to the upper surface of the wafer is always kept uniform even if the generation conditions are changed. As a result, the quality and thickness of the produced CVD film become uniform, and the device manufacturing yield is improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an example of a conventional plasma CVD apparatus.

FIG. 2 is a partial schematic sectional view of an example of a high-frequency electrode according to the present invention.

[Explanation of symbols]

 1 Plasma CVD Device 6 Wafer 7 High Frequency Power Supply 10 Chamber (Reactor) 101 Base 102 Cover Plate 103 Insulation Ring 104 Exhaust Port 20 Susceptor 21 Heater Unit 22 Soaking Plate 30 Nozzle 31, 32 Inlet 40 Shower Electrode 41 Injection Hole 50 Carry In / Carry-out path 51 Gate 52 Carriage 60 Gas dispersion plate 62 First gas reservoir 64 Through hole 66 Second gas reservoir

Claims (3)

[Claims] 1. A susceptor having an aluminum soaking plate constituting a ground substrate electrode on its upper surface and having a heater for heating the aluminum soaking plate, and aluminum facing the ground substrate electrode on the susceptor. In a plasma CVD apparatus having a chamber having a high-frequency electrode made of a perforated plate, a gas dispersion plate having a large number of through holes is provided adjacent to the aluminum perforated plate. . 2. The plasma CVD apparatus according to claim 1, wherein the gas dispersion plate is made of aluminum. 3. The plasma CVD apparatus according to claim 1, wherein the gas dispersion plate is arranged such that the positions of the through holes of the gas dispersion plate and the positions of the through holes of the aluminum perforated plate do not coincide with each other.