JPS63206474A - Photoexcitation cvd device - Google Patents

Abstract

PURPOSE:To prevent deposition of a reaction product on a light introducing window by providing a means for supplying a reactive gas and a sensitizing gas converted to plasma only to the neighborhood of a material to be treated in a photoreaction chamber. CONSTITUTION:The material 4 to be treated is imposed on a sample base 5 in the photoreaction chamber 1 and a sample base 5 is heated by a heater 10. The reactive gas (SiH4, O2, etc.) and the sensitizing gas (Kr, Hg, etc.) converted to plasma by a plasma generating means 20 are charged to a gas supplying pipe 15 of double construction provided to run through the photoreaction chamber 1 and are supplied in the form of a gaseous mixture onto the material 4. Light is then introduced from a mercury lamp 7 through the light introducing window 8 to dissociate and excite the gaseous mixture and to bring the same into reaction on the material 4, by which a deposited film is formed on the material 4. The unreacted gas and sensitizing gas are discharged through a valve 2 by a vacuum pump. Generation of the reaction near the window 8 is thereby obviated and the adverse influence by the deposition to the window 8 is prevented.

Description

Detailed Description of the Invention] (Objective of the Invention) (Industrial Application Field) The present invention is a method of reacting a reaction gas in a photoreaction chamber by irradiating light into the photoreaction chamber containing a workpiece such as a wafer. The present invention relates to an improvement of a photoexcited CVD apparatus that performs vapor phase growth on a workpiece.

(Prior Art) A conventional optically excited CVD apparatus has a configuration as shown in FIG.

That is, a in the figure is a photoreaction chamber, and this photoreaction chamber a is connected to a vacuum pump C through a pulp b. Also,
The photoreaction chamber a is provided with a sample stage e on which a workpiece d, such as a wafer, is placed, and the photoreaction chamber a is provided with a sample stage e on which a workpiece d such as a wafer is placed, and a reaction is carried out through a gas supply pipe f connected to one side of the photoreaction chamber a. Gas Q is now supplied.

Further, a light introduction window j for introducing light from a mercury lamp i whose back is surrounded by a reflector plate is provided in the upper part of the photoreaction chamber a. Further, the sample stage e is heated by a heater m connected to a heater power source k.

Therefore, the reaction gas Q supplied into the photoreaction chamber a through the gas supply pipe f is dissociated by the light introduced directly from the mercury lamp i or once reflected by the reflector and introduced through the light introduction window j. , reacts in the gas phase or similarly on the workpiece d that is irradiated with light, and as a result, a deposited film is generated on the workpiece.

Further, evacuation is performed by a vacuum pump C through a valve b.

(Problems to be Solved by the Invention) However, with such a conventional configuration, the light intensity is higher near the light introduction window j than near the object d, so that the light intensity of the light introduction window j is It also deposits on the surface facing the workpiece d at a faster rate than the deposition rate on the workpiece d.

For this reason, the intensity of light to be supplied to the reactant gas Q in the vicinity of the workpiece d and in the photoreaction space a decreases exponentially, and as a result, the deposition rate on the workpiece d also decreases. It will decrease exponentially.

This has been a very big problem in terms of improving processing speed, reproducibility, and ease of maintenance.

The present invention has been made based on the above circumstances, and its purpose is to cause a reaction only in the vicinity of the object to be treated, and not to cause a reaction in the vicinity of the light introduction window, thereby preventing the adverse effects of deposition on the light introduction window. An object of the present invention is to provide a photoexcited CVD apparatus that can prevent the above.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention aims to reduce the reaction gas in the photoreaction chamber by irradiating light into the photoreaction chamber containing the object to be treated. In a photo-excited CVD system that performs vapor phase growth on the object to be processed by reacting with the sensitizing gas, the reactant gas that would not be dissociated and excited without the sensitizing gas in the photoreaction chamber and the sensitizing gas that has turned into plasma are supplied to the vicinity of the object to be processed. The structure includes a gas supply means for

(Function) That is, the present invention uses a reaction gas for deposition that does not cause a reaction with light alone, but reacts and deposits only when light, a sensitizing gas, and light are present, and furthermore, the reaction of the sensitizing gas is promoted. Since the action has a temporal lifespan, it is possible to cause a reaction only in the vicinity of the object to be treated, and it does not cause a reaction in the vicinity of the light introduction window, making it possible to prevent the adverse effects of deposition on the light introduction window. Become.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 schematically shows the overall configuration. In the figure, 1 is a photoreaction chamber, and the photoreaction chamber 1 is connected to a vacuum pump 3 through a valve 2. The photoreaction chamber 1 is provided with a sample stage 5 on which a workpiece 4 such as a wafer is placed.

Further, a light introduction window 8 for introducing light from a mercury lamp 7 whose back is surrounded by a reflector plate 6 is provided at the upper part of the photoreaction chamber 1, and the sample stage 5 is provided with a heater electrode 21! It is heated by a heater 10 connected to 9.

Further, a double-structured gas supply pipe 15 as a gas supply means is provided to penetrate the photoreaction chamber 1 . As shown in detail in FIG. 2, this gas supply pipe 15 includes an outer pipe 16 forming a reaction gas supply path 12 that communicates with reaction gas supply ports 16a and 16a, and an intensifier that communicates with sensitizing gas supply ports 17a and 17a. It consists of an inner tube 17 that forms a sensitive gas supply path 13, and is configured to be able to supply the separately introduced reaction gas 18 and 41g gas 19 in a mixed state to the photoreaction chamber 1. The part located at is formed in an annular shape.

The annular portion of the inner tube 17 is provided with a plasma generating means 20, which will be described later.
A large number of gas ejection holes 21 are formed for discharging the sensitizing gas 19 turned into plasma by the sensitizing gas 19 into the reaction gas supply path 12 inside the outer tube 16. sensitizing gas 19 and reaction gas 18 turned into plasma
Gas supply holes 23 . . . for supplying a mixed gas 22 with the above-mentioned gas onto the object 4 to be processed are formed.

The plasma generating means 20.20 is composed of a waveguide 24 attached to the inner tube 17 and a microwave oscillator 25, as shown in FIG.

Thus, a mixed gas 2 of a reaction gas 18 for deposition and a sensitizing gas 19 turned into plasma is supplied through the gas supply pipe 15.
2 is supplied onto the object to be processed 4 in the photoreaction chamber 1. The mixed gas 22 supplied into the photoreaction chamber 1 is dissociated and excited by the light introduced through the light introduction window 8 either directly from the mercury lamp 7 or once reflected by the reflection plate 6, and then released into the gas phase or Similarly, the reaction occurs on the object to be treated 4 that is irradiated with light. As a result, a deposited film is generated on the object 4 to be processed.

Next, specific operations will be explained.

First, a reactive gas 18 such as monosilane (S+H4) or oxygen (02) is supplied through the reactive gas supply path 12 in the outer tube 16, while krypton (Kr or mercury<1-NJ
The sensitizing gas 19 which has a sensitizing effect such as
The sensitizing gas is supplied through the sensitizing gas supply path 13 inside. and,
The sensitizing gas 19 supplied through the sensitizing gas supply path 13 in the inner tube 17 is discharged into the reaction gas supply path 12 in the outer tube 16 through the gas jet ports 21 . and is supplied into the photoreaction chamber 1 through gas supply holes 23 formed in the outer tube 16.

For example, when monosilane gas is used as the reaction gas 18, even if a normal mercury lamp 7 is used, the wavelength that the gas can absorb is shorter than the wavelength of the ultraviolet light emitted by the lamp, so the gas does not absorb light and cannot dissociate. . In such cases, it is generally known that when a rare gas such as krypton or mercury is mixed into the reaction gas, these gases absorb light and activate it, indirectly dissociating the monosilane gas. There is.

In this embodiment, activation of a gas with a sensitizing effect is performed more efficiently than with light by converting it into plasma.

As a result, the reaction gas is dissociated, and the dissociated gas, that is, the mixed gas 22 . . . is supplied onto the object 4 from the gas supply holes 23 . At this time, the object to be processed 4 is irradiated with light emitted from the mercury lamp 7, and photovapor phase growth is performed.

Unreacted gas and sensitizing gas that have not been subjected to vapor phase growth are exhausted by a vacuum pump 3 through a valve 2.

Further, when mercury gas is used as the sensitizing gas 19, a mercury trap (not shown) is installed between the photoreaction chamber 1 and the bulb 2, and the mercury gas is exhausted in a recovered state.

Therefore, according to the present invention, the distribution of the reaction gas 18 such as monosilane dissociated does not depend on the light intensity distribution,
It greatly depends on the activated sensitizing gas distribution,
The conventional problem caused by significant deposition near the light introduction window 8 can be solved.

Furthermore, since the sensitizing gas 19 is excited by a more efficient means other than light, it becomes possible to use a gas that could not be used conventionally as the sensitizing gas 19.

In the above embodiment, the reactive gas 18 was made to flow through the outer tube 16 of the double-structured gas supply tube 15, and the sensitizing gas 19 was made to flow through the inner tube 17, but the present invention is not limited to this. Well, the opposite is also fine. Moreover, although the sensitizing gas 19 was turned into plasma by the plasma generation means 20 provided outside the photoreaction chamber 1, it may be turned into plasma inside the photoreaction chamber 1.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the present invention, a reaction occurs only in the vicinity of the object to be treated, and no reaction occurs in the vicinity of the light introduction window, making it possible to prevent the adverse effects of deposition on the light introduction window. It is possible to provide an optically excited CVD apparatus having the following structure.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
FIG. 1 is a schematic configuration diagram of the entire device, FIG. 2 is a partially cutaway plan view of a gas supply pipe, and FIG. 3 is a schematic configuration diagram of a conventional device. 1... Photoreaction chamber, 4... Processed object (wafer), 7.
...Lamp, 8...Light introduction window, 12...Reaction gas supply path, 13...Sensitizing gas supply path, 15...Gas supply pipe, 16...Outer tube, 17... Inner tube, 18... Reaction gas, 19... Sensitizing gas, 20... Plasma generation means, 22... Mixed gas, 23... Gas supply hole. Applicant's agent Patent attorney Takehiko Suzue Figure 3

Claims (2)

[Claims] (1) In a photo-excited CVD apparatus that performs vapor phase growth on the object to be processed by irradiating light into the photoreaction chamber containing the object to be processed by causing a reaction gas in the photoreaction chamber to react, a sensitizing gas is present in the photoreaction chamber. A photo-excited CVD characterized in that a gas supply means is provided for supplying a reaction gas which would otherwise be dissociated and not excited, and a plasma-formed sensitizing gas to the vicinity of the object to be processed.
Device. (2) The gas supply means consists of a double-structured gas supply pipe having a reaction gas supply path for supplying a reaction gas and a sensitizing gas supply path for supplying a sensitizing gas, and mixes the reaction gas and the sensitizing gas. 2. The photoexcitation CVD apparatus according to claim 1, wherein the photoexcitation CVD apparatus is supplied to the photoreaction chamber in a state of