JPH01154515A - Plasma cvd system - Google Patents

Abstract

PURPOSE:To increase the heat transmission efficiency to a wafer under a low pressure, by interposing a metal powder layer having a high thermal conductivity between a uniform heat plate made of metal and heating means. CONSTITUTION:On the upper surface of a susceptor 60, a uniform heat plate 61 made of metal is arranged. The peripheral part of the uniform heat plate 61 is surrounded by a cover 62, and a heating means 63 is arranged under the uniform heat plate 61. In oder that the uniform heat plate 61 may be exchangeable in accordance with the inch-size of a wafer, the plate 61 is fixed to the heating means 63 with screws 64. A metal powder layer 65 is arranged between the uniform heat plate 61 and the heating means 63. For the metal powder, high thermal conductivity material, e.g., Al, Cu can be used, and, in particular, Al powder is preferable. Since the metal powder layer 65 of high thermal conductivity is interposed between the uniform heat plate 61 and the heating means 63, in the case where the uniform heat plate is screwed down a heater, a point contact state between the uniform heat plate and the heater does not occur, so that the heat of the heater is effectively transferred to the wafer through the uniform heat plate, and the fineness of film is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Separation] The present invention relates to a plasma CVD apparatus. More specifically,
The present invention relates to a plasma CVD apparatus having a susceptor that can suppress the generation of foreign matter and improve the uniformity of film thickness.

[Prior Art] One of the methods widely used in the semiconductor industry for forming thin films is chemical vapor deposition (CVD).
Chemical Vapor Depos it
1on). CVD refers to turning a gaseous substance into a solid substance through a chemical reaction and depositing it on a substrate.

Characteristics of CVD are that various thin films can be obtained at deposition temperatures considerably lower than the melting point of the thin film to be grown;
The grown thin film has a high purity and its electrical characteristics are stable even when grown on Si or a thermal oxide film on Si, so it is widely used as a passivation film on semiconductor surfaces.

CVD methods can be broadly classified into three types: (1) normal pressure, (2) reduced pressure, and (3) plasma.

In the plasma CVD method, the energy necessary for reaction activation is obtained by glow discharge plasma in a vacuum. Growth occurs at a low temperature of around 300°C to 400°C, and growth is performed at a low temperature of around 300°C to 400°C. It has the characteristics of good step coverage), strong film strength, and excellent moisture resistance. In addition, the film formation rate (deborate) by plasma CVD method is
Extremely fast compared to the VD method.

[Problems to be solved by the invention] Even in the plasma CVD method, the number of wafers is 300 to 400.
It must be heated to about ℃.

For this reason, heating means such as a heater is provided at the bottom of the metal heat-uniforming plate on which the wafer is placed.

However, in devices that form thin films on wafers under low pressure, such as plasma CVD, the heat from the heater is difficult to transfer to the wafer.
Depending on the mechanical configuration, the actual temperature of the wafer may be 100-200° C. lower than the temperature sensed on the heater.

The reason for this is convection and heat conduction under normal pressure.

This is because heat is transferred by radiation, but under low pressure, heat is transferred only by conduction and radiation, and cannot be transferred by convection, which has a high heat transfer effect.

Further, the heat equalizing plate is configured to be screwed onto the heater so that it can accommodate changes in the inch size of the wafer. However, the negative surface of the heater and the lower surface of the heat equalizing plate are not necessarily subcontracted, and there are irregularities and bends in some places. Therefore, when the heat equalizing plate is screwed onto the heater, the heat equalizing plate becomes in a state as if it is in point contact with the heater, and the heat of the heater is not sufficiently transferred to the heat equalizing plate.

As a result, the density of the film formed by the plasma CVD apparatus does not improve, resulting in a film with poor moisture resistance and high ching rate.

[Problems to be Solved by the Invention] Accordingly, an object of the present invention is to provide a plasma CVD apparatus that can enhance the effect of heat transfer to a wafer under low pressure.

[Means for Solving the Problems] As a means for solving the above-mentioned problems and also achieving the object of the present invention, the present invention provides a method in which a metal heat-uniforming plate constituting a grounded substrate electrode is In the plasma CVD apparatus, the plasma CVD apparatus includes a susceptor having a heating means therein for heating the metal heat-uniforming plate, and a high-frequency electrode facing a grounded substrate electrode on the susceptor. A plasma CVD apparatus characterized in that a metal powder layer with high thermal conductivity is interposed between a plate and a heating means.

[Operations] As described above, in the plasma CVD apparatus of the present invention, a metal powder layer with high thermal conductivity is interposed between the soaking plate and the heating means such as a heater. Therefore, even if the heat equalizing plate is screwed onto the heater, the heat equalizing plate will not come into point contact with the heater.

In this way, the heat from the heater is effectively transferred to the wafer through the soaking plate, and not only the density of the film is improved, but also a thin film with improved overall film quality can be obtained.

[Embodiment] Hereinafter, an example of the apparatus of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic sectional view of a susceptor portion in a plasma CVD apparatus of the present invention.

In FIG. 1, a metal heat equalizing plate 61 is disposed at the L side of the susceptor 60. As shown in FIG. This heat equalizing plate 61 is surrounded by a cover 62 made of an insulating material. A heating means 63 is disposed below the heat equalizing plate 61. The soaking plate 61 is screwed onto the heating means 63 with screws 64 so that it can be replaced depending on the inch size of the wafer. A metal powder layer 65 is provided between the heat equalizing plate 61 and the heating means 63.

The metal powder preferably has high thermal conductivity. For example, A
Metal powders such as J + Cu can be used.

Particularly preferred is Anu powder. The particle size of the powder is not particularly limited. However, in order to ensure surface contact between the heat soaking plate 61 and the heating means 63, the metal powder preferably has a small particle size. The thickness of the metal powder layer is also not particularly limited. Soaking plate 61
The thickness may be sufficient as long as the thickness is sufficient for surface contact between the heating means 63 and the heating means 63.

The heating means 63 can be configured by a resistance heating method, an induction heating method, or the like. Heating force types other than these can also be used.

FIG. 2 shows 11! of an example of the plasma CVD apparatus of the present invention. !
It is a main cross-sectional view.

As shown in FIG. 2, the plasma CV I) of the present invention
The device 1 consists of a housing 10 and a top cover 20 from which the housing 7 can be removed.

The housing 10 includes a bottom wall part 12 and a side wall part 14. A quartz glass window 30 is disposed in a part of the side wall 14 for observing the inside of the reaction chamber, and a first wafer transport mechanism 40 is provided for transporting wafers into and out of the reaction chamber.
A first auxiliary chamber 42 is permanently installed. 1st P
The waiting room 42 and the housing 10 are shut off by a gate valve 44.
Can be configured to communicate. The auxiliary room can also be fixed to another side wall for a total of two rooms. A vacuum υF air duct 46 is provided at the lower part of the side wall portion 14.

A high frequency electrode mechanism 50 is attached to the top cover 20. The high-frequency electrode mechanism 50 has a metal high-frequency electrode 51 at the bottom, which is disk-shaped and has a diameter that is the same as or slightly smaller than the diameter of the susceptor, and has a large number of through holes. This metal high frequency electrode 51 is made of an insulating material 5
2a. Further, this electrode 51 is supported by an electrode support member 54 via an intermediate member 53. The intermediate member 53 and the electrode support member 54 are made of an insulating material 52b.
and 52c from the top cover.

A reactive gas flow path 55 is provided inside the electrode support member 54 . Between the intermediate member 53 and the electrode 51, there is a gas diffusion space 56 that is continuous with the flow path 55. The electrode support member is connected to a visiting frequency power source 57.

A susceptor 60 as described in FIG. 1 is disposed inside the housing 10. The susceptor is supported by struts 80.

The high-frequency electrode plate 51 and the heat soaking plate 61 can be made of aluminum, an aluminum alloy, or a Ni-Cr alloy (also known as "Inconel") having excellent heat resistance.

The insulating cover can be made of a material such as Micarex, for example. Other insulating materials can of course also be used.

[Effects of the Invention] As described below-1, in the plasma CVD apparatus of the present invention, a metal powder layer with high thermal conductivity is interposed between the soaking plate and the heating means such as a heater. Therefore, even if the heat equalizing plate is screwed onto the heater, the heat equalizing plate will not come into point contact with the heater.

In this way, the heat of the heater is effectively transferred to the wafer through the heat soaking plate, and not only the density of the film is improved, but also a thin film with improved overall film quality can be obtained.

Furthermore, to avoid heating the heater, etc. to higher temperatures than necessary,
The lifespan of heaters and the like is extended, and the frequency of replacement is reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial cross-sectional view of a susceptor in a plasma CVD apparatus of the present invention, and FIG. 2 is a schematic cross-sectional view of an example of the plasma CVD apparatus of the present invention. ■... Plasma CVD device, 10... Housing, 12...
...Bottom wall part, 14...Side wall part, 20...Top cover. 30... Window section, 40... First wafer transfer mechanism, 42
...First preliminary room, 44...Gate pulp, 46...
・Vacuum exhaust duct, 50...High frequency electrode mechanism, 51・
・・Metal high frequency electrode, 52a, 52b, 52cm・
·Insulating material. 53... Intermediate member, 54... Electrode support member, 55...
...Reaction gas flow path, 56... Gas diffusion space, 57...
- High frequency power supply, 60... Susceptor, 61... Soaking plate, 62... Insulating cover, 63... Heating means for soaking plate, 64... Screw.

Claims (2)

[Claims] (1) A susceptor having a metal heat-uniforming plate constituting a grounded substrate electrode on its upper surface and having a heating means inside for heating this metal heat-uniforming plate, and facing the grounded substrate electrode on this susceptor. A plasma CVD apparatus having a high-frequency electrode, characterized in that a metal powder layer with high thermal conductivity is interposed between the metal heat soaking plate and the heating means. (2) The plasma CV according to claim 1, wherein the metal powder layer is made of Al powder.
D device.