JPH0729844A - Infrared heating method and equipment for semiconductor substrate - Google Patents

Abstract

PURPOSE:To heat a semiconductor substrate such that a uniform in-plane temperature distribution is obtained by covering the inner wall of a treating vessel at least partially with an infrared ray absorbing material and conducting the irradiation of infrared ray through a transmission window toward the rear side of the semiconductor substrate where no device pattern is formed. CONSTITUTION:A semiconductor substrate 12 to be treated is supported above an infrared ray transmission window 13 through substrate supporting pins 16 with the rear side, formed with no device pattern 18, opposing the transmission window 13. The substrate 12 is irradiated through the transmission window 13 with infrared rays emitted from infrared lamps 14 after the density thereof being made uniform by an infrared reflector 17. Since the inner wall face of a heat treatment vessel 11 is covered with a thin plate 15 of SiC having high infrared absorptivity, the infrared ray scarcely reflect thereon and the substrate 12 is heated only from the rear side where the in-plane infrared absorptivity is uniform thus realizing a uniform temperature distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared heating method for a semiconductor substrate in manufacturing a semiconductor device and an infrared heating apparatus used for the method.

In recent years, in the manufacture of semiconductor devices,
With the advancement of process technology, a heat treatment technology for heating a semiconductor substrate at a faster temperature rising rate and at a higher temperature uniformity is required, and in order to respond to this, substrate heating using an infrared heating device is required. A method is provided. However, when a semiconductor substrate is heated by infrared rays, it is not easy to obtain a uniform temperature distribution in the substrate surface, and development of infrared heating technology that can easily ensure temperature uniformity is desired.

[0003]

2. Description of the Related Art FIG. 4 is a diagram schematically showing the configuration of a conventional infrared heating device, and FIG. 5 is a diagram showing the configuration of an improved example of the conventional infrared heating device.

As shown in FIG. 4, an infrared heating device conventionally used in the manufacturing process of a semiconductor device has an infrared transmission window 53 made of quartz or the like on the bottom surface of a sealed heat treatment container (heat treatment chamber) 51. , Substrate support pins on this transparent window 53
The semiconductor substrate 52 to be processed is supported substantially horizontally via 56, an infrared lamp 54 is arranged in the heating light source chamber 60 below the transmission window 53, and the infrared IR emitted from the lamp 54 is transferred to the transmission window.
The back surface of the semiconductor substrate 52 to be processed on which the device pattern is not formed is irradiated through 53. Incidentally, 57 indicates an infrared reflection plate, and 58 indicates a device pattern.

The heat treatment container 51 is made of a metal such as stainless steel in a rectangular box shape, and its inner surface is mirror-finished to improve reflection of infrared rays. In such a conventional infrared heating device, the semiconductor substrate 52 to be processed has an infrared IR that is directly irradiated to the back surface through the infrared transmission window 53 and an infrared IR ′ that is reflected on the inner surface of the processing container 51 and is irradiated to the front surface. , Heated from both sides.

At this time, by making the density of the infrared rays passing through the infrared transmitting window 53 uniform, the infrared heating from the back surface side of the semiconductor substrate 52 to be processed which is directly irradiated with the infrared IR passing through the infrared transmitting window 53 is prevented. A uniform temperature distribution can be achieved.

On the other hand, the heating from the surface side of the substrate 52 causes the infrared rays IR 'radiated to the surface of the substrate 51 to be irregular because the infrared rays IR' reflected on the inner surface of the processing vessel 51 are formed in a box shape. Since the distribution is not uniform, the temperature distribution is not uniform over the entire surface.

Therefore, it has been extremely difficult to obtain a uniform temperature distribution on the semiconductor substrate 52 to be processed by using the above conventional infrared heating device. Therefore, in order to obtain a uniform temperature distribution, conventionally, an improved example of an infrared heating device having a structure as shown in FIG. 5 has been proposed.

The difference between this structure and the conventional structure is that
The ceiling surface 51C of the processing container 51 is formed into a spherical shape,
Infrared IR ′ reflected on the inner surface of the substrate is evenly processed semiconductor substrate
This is the point where the surface of 52 is irradiated. Other structures are the same as those of the conventional example, and each reference numeral indicates the same object as in FIG.

When this apparatus is used, the same substance such as a semiconductor substrate is exposed on the entire surface, and the infrared heating of the semiconductor substrate to be processed from the back side where the infrared absorption rate of the entire surface is uniform is uniform as in the conventional apparatus. Done.

However, the in-plane infrared absorptivity is not uniform on the surface of the semiconductor substrate 52 to be processed on which the device pattern is formed due to the selective existence of the insulating film or the metal pattern having a different infrared absorptivity. . Therefore, even if the structure shown in FIG. 5 is adopted and the distribution of the infrared rays IR ′ reflected on the inner wall of the processing container 51 and applied to the surface of the semiconductor substrate 51 to be processed is made uniform, the semiconductor substrate 51 to be processed is Infrared heating from the surface side is not always uniform over the entire surface.

Therefore, even in this conventional improvement example, the in-plane uniform temperature distribution of the semiconductor substrate 51 to be processed cannot be sufficiently obtained, which causes a problem that the performance and manufacturing yield of the semiconductor device are deteriorated. Was there.

[0013]

Therefore, the present invention provides an infrared heating method and an infrared heating apparatus for a semiconductor substrate which can heat a substrate to be processed so as to obtain a sufficiently uniform in-plane temperature distribution. The purpose is to

[0014]

In order to solve the above-mentioned problems, a semiconductor substrate arranged in a hermetically sealed processing container is irradiated with infrared rays through a transmission window provided on the vessel wall of the processing container to provide infrared rays to the semiconductor substrate. In the present invention, at the time of heating, at least a part of the inner wall of the processing container is covered with an infrared absorber, and the infrared rays are irradiated toward the back surface of the semiconductor substrate on which the device pattern is not formed, through the transmission window. The method for infrared heating a semiconductor substrate according to claim 1, or a processing container in which a substrate to be processed is arranged has an infrared transparent window on a container wall and at least a part of the inner wall surface is covered with an infrared absorbing material. The infrared heating device according to the present invention, or the infrared heating device according to the present invention, wherein the substrate to be processed has a back surface side on which a device pattern is not formed facing the infrared transmission window. Is accomplished by infrared heating device according to the invention is arranged Te.

[0015]

1 is a schematic sectional view for explaining the principle of the present invention, in which 1 is a heat treatment container (heat treatment chamber), 2 is a semiconductor substrate to be processed, 3 is an infrared transmitting window, 4 is an infrared lamp, and 5 is infrared. Absorber, 6 is a substrate support pin, 7 is an infrared reflecting plate, 8 is a device pattern, and 10 is a heating light source chamber.

In the infrared heating method for a semiconductor substrate according to the present invention, as shown in the figure, an infrared IR generated from an infrared lamp 4 serving as a heating light source is transferred to the back surface of the semiconductor substrate 2 to be processed without the device pattern 8. Irradiation is performed uniformly through the transmission window 3, and the semiconductor substrate 2 to be processed 2
Infrared IR irradiating the inner wall of the heat treatment container 1 from the periphery of the is absorbed by the infrared absorber 5 adhered to the inner wall surface of the processing container 1, and is reflected by the inner wall of the container 1 to form the device of the semiconductor substrate 2. Infrared rays emitted to the surface side having the pattern 8 are eliminated. Therefore, it is possible to suppress the non-uniformity of the heating temperature in the surface of the substrate to be processed, which is conventionally caused by being reflected from the inner wall of the processing container and being heated from the surface side of the semiconductor substrate having a non-uniform infrared absorption rate. Become.

Further, in the infrared heating device of the present invention,
An infrared absorber is deposited on the inner wall surface of the processing container 1 to prevent the infrared IR incident from the infrared transmission window 3 from being reflected on the inner wall surface of the processing container 1 and being irradiated to the substrate to be processed. The heating of No. 2 is directly performed only by the infrared IR having a uniform intensity distribution which is incident from the infrared transmitting window 3 to achieve the heating uniformity. Further, in the apparatus as an example thereof, the substrate to be processed is further arranged such that the back surface side thereof on which the device pattern is not formed and which has a uniform infrared absorption rate is opposed to the infrared transmission window 3, and the uniform incidence of light from the transmission window 3 is made. An infrared ray having an intensity distribution is uniformly irradiated to the entire back surface of the substrate 2 to be processed, and the infrared ray reflected by the inner wall surface of the processing container 1 is suppressed to the surface side having a non-uniform infrared absorption rate as described above. In addition to the effect of eliminating the heating of the substrate 2 to be processed from above, the infrared heating of the substrate to be processed is further homogenized.

As described above, according to the present invention, the semiconductor process using infrared heating can be made uniform, and improvement in the quality and manufacturing yield of semiconductor devices can be expected.

[0019]

EXAMPLES The present invention will be described in detail below with reference to illustrated examples. FIG. 2 is a schematic sectional view of an embodiment of the infrared heating apparatus according to the present invention, and FIG. 3 is a schematic sectional view of another embodiment of the same. The same object is denoted by the same reference numeral throughout the drawings.

An infrared heating device according to the present invention is shown in FIG.
It is configured as shown in. That is, for example, it is made of metal such as stainless steel, is hermetically sealed and can be evacuated, and the liquid cooling means 19A
The bottom surface of the box-shaped heat treatment container 11 provided with is composed of an infrared transmission window 13 having a liquid cooling means 19B which is made of, for example, transparent quartz and which does not prevent the transmission of infrared rays, which is formed of a cooling liquid circulation space, The entire inner wall surface of the container 11 is covered with an infrared absorbing material, for example, a black silicon carbide (SiC) thin plate 15. A substrate supporting pin 16 made of transparent quartz is also provided on the upper surface of the infrared transmitting window 13, and the semiconductor substrate 12 to be infrared-heated is placed on the infrared transmitting window 13 via the supporting pin 16 such as an infrared transmitting window. It is supported almost parallel to 13. Further, a plurality of infrared lamps 14 which are heating light sources are arranged in parallel to the infrared transmission window 13 in the heating light source chamber 20 provided in the lower part of the processing container 11, that is, the lower part of the infrared transmission window 13, and the infrared reflection is provided behind them. A plate 17 is provided so that the density of infrared IR passing through the infrared transmitting window 13 is made uniform. A tungsten halogen lamp, for example, is used as the infrared lamp 14.

In one embodiment of the infrared heating method for a semiconductor substrate according to the present invention, the infrared heating apparatus shown in FIG. 2 is used to perform infrared heating of the semiconductor substrate 12 to be processed in vacuum.

The semiconductor substrate 12 to be processed is, for example,
A device having a non-uniform infrared absorptivity by selectively providing a region (not shown) on the surface of which a silicon surface is exposed and ion-implanted with impurities and a silicon oxide film (not shown) defining the region. A silicon substrate having a pattern 18 and having silicon exposed on the entire back surface is applied, and an activation process is performed by rapid heating of the region into which the impurities are ion-implanted.

In the infrared heat treatment, an infrared transparent window
Through the substrate support pins 16 on the substrate 13, the device pattern is not formed, silicon is exposed on the entire surface, and the back surface having a uniform in-plane distribution of infrared absorption coefficient is opposed to support the semiconductor substrate 12 to be processed. , Through the infrared transmitting window 13 toward the back surface of the semiconductor substrate 12 to be processed, the infrared rays are generated by the infrared lamp 14 and the density is made uniform by the infrared reflecting plate 17.
IR irradiation is performed.

This infrared irradiation is carried out for about 2 to 3 minutes at a strength at which the semiconductor substrate 12 to be processed is heated to about 800 ° C. to activate the ion-implanted region of the impurities. At that time, infrared rays are radiated toward the inner wall surface of the heat treatment container 11 from the portion of the infrared transmission window 13 exposed to the periphery of the substrate to be processed 12, but the heat treatment is performed in the infrared heating device of the embodiment according to the present invention. Since the inner wall surface of the container 11 is covered with the SiC thin plate 15 which is black and has a high infrared absorption rate (about 90%), the infrared light is hardly reflected from the inner wall surface of the processing container. Also,
In the apparatus of this embodiment, since the inner wall of the heat treatment container 11 is cooled by the liquid cooling means 19A and kept at a low temperature, infrared radiation from the inner wall surface of the heat treatment container 11 does not occur.

Therefore, since the heating of the semiconductor substrate 12 to be processed is regarded as the infrared ray having the uniform irradiation density from the back surface side where the in-plane infrared absorption rate is uniform, the semiconductor substrate 12 to be processed is treated.
Are heated to a sufficiently uniform temperature distribution.

Further, in another embodiment of the infrared heating apparatus shown in FIG. 3, in order to prevent the inside of the heat treatment container from being contaminated, inside the heat treatment container 11 made of metal similar to the above embodiment,
An inner container 21 capable of cleaning quartz or the like is provided, and a black SiC thin plate 15 which is an infrared absorbing material similar to the above embodiment is adhered to the entire outer wall surface of the inner container 11.

The structure of the other parts is the same as the structure of the embodiment shown in FIG. In this structure, the contaminants emitted from the infrared absorption section, that is, the SiC thin plate 15 by infrared irradiation do not adhere to the semiconductor substrate to be processed, and in addition to the soaking effect similar to the above embodiment, the contamination of the semiconductor substrate to be processed is The effect of preventing.

It should be noted that even if the deposition of the infrared absorbing material is not limited to the entire surface of the inner wall surface of the processing container as in this embodiment, but is limited only to the region of the inner wall surface where the infrared rays are directly irradiated, the effect similar to that of the embodiment is obtained. It is possible to get.

Further, the infrared absorbing material is preferably a substance having an infrared absorption rate of 90% or more and heat resistance of 500 to 600 ° C. or more. In addition to SiC shown in the examples, a coating film of carbon or graphite, etc. Is also used.

Further, the infrared lamp used as the heating light source contains the absorption wavelength of the semiconductor and is transmitted through the quartz transmission window.
An infrared lamp having an arbitrary emission spectrum in the range of 0.3 to 5.0 μm is desirable.

The material of the infrared transmitting window is not limited to quartz as long as the material has a sufficiently high infrared transmittance including the absorption wavelength of the substrate to be processed.

[0032]

As described above, according to the present invention, when the semiconductor substrate is heated by infrared rays, the in-plane distribution of the heating temperature can be made sufficiently uniform.

Therefore, according to the present invention, the semiconductor substrate can be heated at a high temperature rising rate and at a uniform temperature, and the quality and the manufacturing yield of the semiconductor device using the infrared heating means in the manufacturing process can be improved. There is a big contribution.

[Brief description of drawings]

FIG. 1 is a schematic sectional view for explaining the principle of the present invention.

FIG. 2 is a schematic sectional view of an embodiment of an infrared heating device according to the present invention.

FIG. 3 is a schematic cross-sectional view of another embodiment of the infrared heating device according to the present invention.

FIG. 4 is a schematic sectional view of a conventional infrared heating device.

FIG. 5 is a schematic sectional view of an improved example of a conventional infrared heating device.

[Explanation of symbols]

 1 heat treatment container (heat treatment room) 2 semiconductor substrate to be processed 3 infrared transmission window 4 infrared lamp 5 infrared absorber 6 substrate support pin 7 infrared reflection plate 8 device pattern 10 heating light source room

Claims (3)

[Claims] 1. An inner wall of a processing container when a semiconductor substrate arranged in a closed processing container is irradiated with infrared rays from a transmission window provided on a vessel wall of the processing container to heat the semiconductor substrate by infrared rays. At least a part of which is covered with an infrared absorber, and the irradiation of the infrared rays is performed toward the back surface of the semiconductor substrate on which the device pattern is not formed, through the transmission window. 2. The processing container in which the substrate to be processed is arranged is a hermetically-sealed container having an infrared transmitting window on a container wall and at least a part of the inner wall surface thereof being covered with an infrared absorbing material. A characteristic infrared heating device. 3. The infrared heating apparatus according to claim 2, wherein the substrate to be processed is arranged such that a back surface side on which no device pattern is formed faces the infrared transmission window. Infrared heating device.