JPH0410410A - Thin film processing equipment - Google Patents

Abstract

PURPOSE:To enable high-quality films at low temperature without deterioration such as thermal distortion by providing infrared lamps and ultraviolet lamps for irradiating the deposition surface of a substrate S installed in a reaction tube. CONSTITUTION:An Si substrate S is installed on a susceptor 2; then a reaction tube 1 is kept hermetic with hydrogen gas atmosphere and pressure-reduced, and this state is retained. With the susceptor 2 driven by rotation, infrared lamps 3<3 are switched on to heat the substrate S by irradiation with infrared rays. At this time, ultraviolet lamps 4, 4 are turned on, too, to irradiate the deposition surface of the substrate S with ultraviolet rays. This state is retained for a given period of time for hydrogen baking of the substrate S. Next, disilane gas and hydrogen gas are introduced simultaneously into a reaction tube 1 to make an Si thin film epitaxially grown from the surface of the substrate S. After completion of film deposition, the reaction tube 1 is filled with hydrogen gas atmosphere again, and next infrared lamps and ultraviolet lamps 3, 4 are switched off.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for growing a thin film on the surface of a semiconductor substrate, etc., and more particularly relates to an apparatus for forming a thin film on the surface of a substrate by chemical vapor deposition. .

<Prior Art> In general, semiconductor devices are manufactured by using a wafer as a substrate as a starting material, forming various films on the substrate, and processing the substrate by diffusing impurities into the substrate or etching the substrate.

In recent years, as semiconductor devices have become more highly integrated and have higher performance, and semiconductor substrates have become larger in diameter, the manufacturing conditions required for each process for manufacturing these semiconductor devices have become increasingly strict.

In the manufacturing process of semiconductor devices, in the thin film formation process in which single crystal, polycrystalline, and amorphous materials are formed on a semiconductor substrate, it is important to lower the film formation temperature, improve the quality of the thin film, and improve film uniformity. requested.

For example, an apparatus for growing a Si thin film on the surface of a Si substrate by vapor phase epitaxial growth is, as shown in FIG. The substrate (substrate) is heated by infrared irradiation from an infrared lamp 23 installed outside the reaction tube 21, and in this state hydrogen gas and raw material gas such as silane are introduced into the reaction tube 21, so that the surface of the substrate is heated. It is configured to epitaxially grow a Si thin film.

However, in such an apparatus, when the reaction temperature is set to a low temperature of, for example, about 600° C., normal epitaxial growth cannot be performed. This is said to be caused by insufficient thermal decomposition reaction of the raw material gas such as silane gas and insufficient activation of atoms on the substrate surface. Therefore, in order to perform epitaxial growth at low temperatures, it is necessary to promote the above-mentioned thermal decomposition reaction and activation by other methods.

Conventional methods for promoting reaction activation include methods using plasma and ECR (electron cyclotron resonance), and methods using laser and ultraviolet light.

FIG. 3 shows an example of a conventional configuration of an optical epitaxial growth apparatus using ultraviolet light.

A semiconductor substrate S placed on a support stand 32 installed inside a reaction tube 31 made of quartz is heated by an infrared lamp 33 installed at the bottom of the reaction tube 31.
While the surface of the semiconductor substrate S is irradiated with ultraviolet light by a mercury lamp 34 installed above the reactor tube 31, hydrogen gas and raw material gas are introduced into the reaction tube 31 to epitaxially grow Si on the substrate. By irradiating the surface of the semiconductor substrate S with ultraviolet light in this manner, growth reactions and the like are promoted, thereby allowing normal epitaxial growth even at a low reaction temperature of about 600''C.

<Problems to be Solved by the Invention> By the way, according to the optical epitaxial growth apparatus shown in FIG. The substrate is heated to a high temperature, creating a temperature difference between the front and back sides of the substrate, causing thermal distortion in the substrate.

This thermal strain has various adverse effects on the formed thin film and semiconductor substrate. Moreover, there is a problem in that heat loss during substrate heating is large.

In addition, since the infrared lamps are installed tightly below the semiconductor substrate, it is not possible to provide a mechanism to rotate the substrate, and as a result, the resulting thin film is not sufficiently uniform in film quality and thickness. There is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that is less likely to cause deterioration such as thermal strain on a substrate and can obtain a high-quality thin film at a low temperature.

<Means for Solving the Problems> The configuration for achieving the above object will be explained with reference to FIG. 1 corresponding to the embodiment. In an apparatus for growing a thin film on the surface of a substrate S by heating and guiding a reactive gas to the surface of the substrate S, for irradiating infrared rays and ultraviolet rays onto the film forming surface of the substrate S installed in the reaction tube 1. , each light source (infrared lamp and ultraviolet lamp) 3...
3.44.

<Function> By directly irradiating the surface of the substrate S placed in the reaction tube 1 with infrared rays, heating efficiency is improved, thereby reducing the temperature difference between the front and back sides of the substrate. Furthermore, by simultaneously irradiating the film-forming surface of the substrate S with infrared rays and ultraviolet rays, heat loss is reduced and the efficiency of reaction growth is improved.

Further, a space can be secured below the substrate S to install a rotation mechanism and the like.

<Example> Fig. 1 is a block diagram of an example of the present invention, in which (a) is a side view showing the reaction tube 1 cut in a direction perpendicular to its axial direction, and (b) is a side view showing the reaction tube 1 in its axial direction. FIG. 3 is a side view cut along the axial direction. In addition, in (b), only one part of the reaction tube is shown.

A support stand 2 is disposed inside a reaction tube 1 made of quartz, and a substrate S on which a film is to be formed is mounted on this support stand 2. The support stand 2 is supported by a shaft 5a of a rotation mechanism 5 provided below and outside the reaction tube 1. Note that the reaction tube 1 is formed into a cylindrical shape or a cylindrical shape with a certain degree of curvature so that film formation can be performed under reduced pressure.

A gas introduction port is provided on one opening 1a side of the reaction tube 1, and a carrier gas and a reaction gas supply source (both not shown) are connected to this gas introduction port, respectively. Further, a pressure control device (not shown) is connected to the other opening, the gas discharge port 1b.

A plurality of infrared lamps 3 are installed around the outside of the reaction tube 1.
3 are arranged, and by lighting these infrared lamps 3, both the front and back surfaces of the substrate S placed on the support stand 2 can be irradiated with infrared rays. Furthermore, an ultraviolet lamp 4 such as a mercury lamp is disposed outside the reaction tube 1 at a position above the substrate S placed on the support stand 2 and at a position that does not interfere with the infrared lamp group 3...3. By lighting the ultraviolet lamp 4, the surface of the substrate S, that is, the film-forming surface, can be irradiated with ultraviolet rays. In addition, on the outside of each lamp 3 or 4,
Arc-shaped reflecting plates 6 or 7 are respectively provided to guide infrared rays and ultraviolet rays into the reaction tube 1 without leaking them to the outside.

In addition, the reaction tube 1, each lamp 3.4, and each reflection plate 6, 7
These are designed to be sufficiently cooled by cooling water or cooling air, respectively.

Next, a procedure for growing a Sin film on a St single crystal substrate (wafer) will be explained using the above-described embodiment of the present invention. Note that hydrogen gas is used as a carrier gas, and disilane (SiJ6) is used as a reaction gas.

First, the Si substrate S is placed on the support 2, and then the inside of the reaction tube 1 is kept airtight. In this state, hydrogen gas is first introduced into the reaction tube 1 to create a hydrogen gas atmosphere inside the reaction tube 1. , the internal pressure is reduced to 10 Torr by the pressure control device, and this state is maintained.

Next, while the support base 2 is rotationally driven, the infrared lamp 3
... 3 is turned on and the substrate S is irradiated with infrared rays to heat the substrate S to 700°C. At this time, the ultraviolet lamp 4.4 is also turned on to irradiate the film-forming surface of the substrate S with ultraviolet light.

Then, this state is maintained for 10 minutes and the substrate S is subjected to hydrogen baking treatment.

Next, disilane gas and hydrogen gas are simultaneously introduced into the reaction tube 1 to epitaxially grow a Si thin film on the surface of the substrate S. The film forming time is about 20 minutes. Further, the internal pressure of the reaction tube 1 during film formation is 10 Torr.

After the film formation is completed, the inside of the reaction tube 1 is made into a hydrogen gas atmosphere again, and then each of the infrared and ultraviolet lamps 3
．． 4 lights out. After that, when the temperature of the substrate S drops to about room temperature, the rotation of the support stand 2 is stopped, the introduction of hydrogen gas is stopped, and the inside of the reaction tube 1 is purged with nitrogen gas, and then the substrate S is placed in the reaction tube. Take it out from 1.

The surface of the Si film grown on the Si substrate according to the above procedure was etched with an etchant for evaluating crystal defects and observed with an optical microscope, and it was found that a high-quality epitaxial growth layer with no slips or defects was formed. was confirmed. Furthermore, when the film thickness and specific resistance were measured, good results were obtained in terms of uniformity.

Here, in the above-described embodiment of the present invention, since infrared rays can be irradiated to both the front and back surfaces of the substrate S in the reaction tube 1, the heating of the substrate S is uniform throughout, and thermal distortion of the substrate S is reduced. It is possible to further reduce the negative effects caused by Moreover, by performing the growth reaction under reduced pressure, it becomes possible to obtain a thin film of better quality at a lower temperature.

Note that the respective positions of the infrared and ultraviolet lamps 3 and 4 are not particularly limited as long as they can irradiate the film-forming surface of the substrate S placed on the support stand 2 with infrared and ultraviolet rays.

Moreover, the number of each lamp can also be set to an arbitrary number.

Further, in the above embodiments of the present invention, an example in which a 5iFi4 film is epitaxially grown has been described, but the invention is not limited to this, and by appropriately changing the gas introduced into the reaction tube 1, it is possible to grow polycrystalline Si, for example. Thin film or S
It is also possible to grow other thin films such as i-nitride films.

Furthermore, the present invention is also applicable to other common chemical vapor deposition apparatuses that grow polycrystalline or amorphous thin films on substrate surfaces.

<Effects of the Invention> As explained above, according to the present invention, since the film forming surface of the substrate placed in the reaction tube is configured to be irradiated with infrared rays and ultraviolet rays simultaneously, there is little thermal distortion of the substrate, etc. Moreover, as a result of highly efficient reaction growth with less heat loss, it is possible to obtain thin films of better quality than in the past. Furthermore, it becomes possible to install a mechanism for rotating the substrate, and the resulting thin film has good film quality and uniformity in film thickness.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention. FIGS. 2 and 3 are diagrams each showing an example of a conventional structure of a vapor phase epitaxial growth apparatus. 1...Reaction tube 2...Support stand 3...3...Infrared lamp 4...Ultraviolet lamp 5-...Rotation mechanism S...Substrate

Claims (1)

[Claims] In an apparatus that grows a thin film on the surface of a substrate by heating the substrate to a predetermined temperature in a reaction tube and introducing a reactive gas to the surface of the substrate, infrared and ultraviolet rays are applied to the film-forming surface of the substrate placed in the reaction tube. 1. A thin film manufacturing device characterized by being equipped with respective light sources for irradiating.