JPS61159574A - Reactor for vapor phase reaction by high frequency induction heating - Google Patents

Abstract

PURPOSE:To enable a vapor phase reaction by high frequency induction heating under reduced pressure by dividing a vertical reactor for a vapor phase reaction by high frequency induction heating into a vapor phase reaction part and a high frequency coil part and by airtightly isolating the parts from each other. CONSTITUTION:The vertical reactor for the vapor phase reaction by the high frequency induction heating is divided into a reaction furnace 1 in which the vapor phase reaction is carried out and a part in which the high frequency coil 2 is placed at the outside of the furnace 1. Even when the furnace 1 is evacuated, the coil 2 part is kept under desired pressure, so the abnormal discharge under reduced pressure is prevented. Since no metal enter the furnace 1 from the coil 2, the contamination of a wafer or the like by contaminants is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vertical gas phase reactor using high frequency induction heating.

[Conventional technology]

High-frequency induction heating using a high-frequency coil is widely used in gas-phase reactors. For example, such high frequency induction heating is widely used in epitaxy equipment.

However, when a vertical type is used to perform a gas phase reaction using high-frequency induction heating, if a reduced pressure type is used, the problem of abnormal discharge occurs.

For example, in a pancake-type vertical reactor, which is a type of vertical gas-phase reactor, the high-frequency coil 2' is
Since it is located inside the reactor 1' defined by a bell jar 11' (usually made of quartz), when the pressure inside the reactor is reduced,
The high frequency coil 2' will also be placed under reduced pressure, thus causing abnormal discharge. When abnormal discharge occurs, the load impedance changes significantly, and the discharge becomes unstable.
The oscillator may be damaged. (In Figure 1, 3' is the carbon support, 4' is the wafer, 5' is the quartz cover, and the arrow is the gas flow.) In practice, when the pressure inside the furnace is set to about 100 to 200 Torr. It is difficult to heat above 1100° C. without discharge, and the problem of discharge is unavoidable.

In a high pressure range of 200 Torr or more without much pressure reduction, there is not much of a problem with discharge, but in order to use a pressure reduction type, it is still necessary to solve the problem of discharge.

In the end, in the conventional gas phase reactor using high frequency induction heating,
As the degree of vacuum increases (for example, when P≦100 Torr), discharge becomes more likely to occur, so in reality P≦10
Vapor phase growth at 0 Torr is difficult and virtually impossible.

[Purpose of the invention]

An object of the present invention is to provide a vertical gas phase reactor capable of high-frequency induction heating under reduced pressure.

[Structure of the invention]

The vertical gas phase reactor using high frequency induction heating of the present invention is
By separating the part where the gas phase reaction takes place and the part where the high-frequency coil is located, the configuration is such that the two parts can have different pressures.

[Action of the invention]

As a result of the above configuration, the reactor where the gas phase reaction takes place is separated from the high-frequency coil section that causes abnormal discharge, so even if the pressure inside the furnace is reduced, the high-frequency coil section will be at an arbitrary pressure, that is, higher than the furnace internal pressure. Since the pressure can be maintained at normal pressure or low pressure, it is possible to prevent abnormal discharge that would otherwise occur due to reduced pressure in the area where the high-frequency coil is located. Therefore, a gas phase reaction by high frequency induction heating under reduced pressure becomes possible.

In addition, by separating the two parts, the capacity of the furnace itself can be reduced, and therefore the bell jar, which is generally made from quartz, can be made smaller. In addition, the furnace purge can be shortened. Further, it is possible to suppress metal contaminants from entering the furnace from the high-frequency coil, and it is possible to prevent wafers and the like from being contaminated by metal. In addition, the purge gas for the high-frequency coil section can be replaced by inexpensive nitrogen.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a so-called pancake-type vertical furnace.

In this example, by installing the high-frequency coil 2 outside the reactor 1, the reactor 1 where the gas phase reaction is performed is separated from the part where the high-frequency coil 2 is located.

A graphite susceptor 3 on which a wafer or the like to be heated is placed is installed in the furnace so as to be close to the high frequency coil 2, which is a work coil.

In this example, a reactor 1 is defined by a stainless steel bell jar 118 (water-cooled) and a quartz inner bell jar 11, and a reaction gas (hydrogen or silane gas) is sent into the reactor from a quartz nozzle 4. It is configured.

As mentioned above, the high-frequency coil 2 is installed outside the reactor 1 to separate the two, so the gas phase reaction can be performed under reduced pressure, and even in that case, the high-frequency coil 2 is affected by the effect of the reduced pressure Therefore, even if the reaction is carried out under reduced pressure conditions of 100 Torr or less, the high-frequency coil 2 can be placed under normal pressure (or low pressure), and no problems such as discharge will occur under reduced pressure. Gas phase reactions are possible.

With the configuration of this example, it is possible to suppress metal contaminants from entering the furnace from the high-frequency coil 2, and to prevent wafers and the like from being contaminated by metal. Cheap nitrogen can also be used as the purge gas for the high frequency coil section. Furthermore, since the length of the high-frequency coil 2 in the vertical direction (vertical direction in FIG. 1) may be reduced by extending the high-frequency coil 2 to the outside, it is also possible to reduce the capacity of the furnace itself. For this reason, Bellja (
In particular, it is advantageous that the quartz belljar 11) can be made smaller.

In addition, the furnace purge time can be shortened.

Shown in FIG. 2 is another embodiment of the invention.

This example uses Belljar 11. A storage section 21 for the high-frequency coil 2 is formed in the space defined by the lla, and the storage section 21 is airtightly separated from the reaction section 1a where the gas phase reaction is performed, so that the pressures of both sides are different. This made it possible.

This example also exhibits the same effects as the previous example. In addition, in this example, the pressure in the high frequency coil 2 can be controlled more reliably. In FIG. 2, the same reference numerals are given to the same components as in the above example.

It should be noted that, as a matter of course, the present invention is not limited to the illustrated example.

〔Effect of the invention〕

As described above, the vertical gas phase reaction apparatus of the present invention solves the problem of high frequency coil discharge and enables gas phase reaction by high frequency induction heating under reduced pressure.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are sectional views each showing an embodiment of the present invention. FIG. 3 shows a conventional example. 1, la... Reaction furnace (gas phase reaction section), 2... High frequency coil, 21... High frequency coil storage section.

Claims (1)

[Claims] 1. In a vertical gas phase reaction device using high frequency induction heating, by separating the part where the gas phase reaction takes place and the part where the high frequency coil is located, it is possible to make sure that the two parts have different pressures. A high-frequency induction heating gas phase reactor that has been made possible. 2. The high-frequency induction heating gas-phase reaction apparatus according to claim 1, wherein the pressure inside the reactor in which the gas-phase reaction is carried out is reduced, and the high-frequency coil is placed under normal pressure or under a pressure higher than the pressure inside the furnace.