JPH0620938A - Quick thermal oxidizing apparatus for semiconductor substrate - Google Patents

Abstract

PURPOSE:To provide a quick thermal oxidizing apparatus for a semiconductor substrate having a high temperature measuring accuracy by using a radiant pyrometer. CONSTITUTION:When a semiconductor substrate 1 is quickly heated by using a plurality of heating lamp groups 3, 4 so arranged as to perpendicularly cross to each other oppositely to upper and lower surfaces through the substrate 1 and a temperature of the upper surface of the substrate 1 is measured by a radiant pyrometer 7 through an opening 11 opened at a reflecting plate 5 of the upper surface side, a radiant light from the group 4 of the lower surface is shielded by a shielding shutter 8 openably disposed between an opposite measuring surface of the substrate and the group 4 of the lower surface, thereby measuring the surface temperature of the substrate 1 in a high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid thermal oxidation device for semiconductor substrates.

[0002]

2. Description of the Related Art It is no exaggeration to say that the progress of LSIs up to now is supported by the development of fine processing technology. For example, in the process of 64-Mbit DRAM level, the rapid thermal oxidation process (hereinafter,
RTP (Rapid Thermal Processing) device
Are said to be promising.

This RTP device is typically disclosed in, for example, US Patent No. 4680451. That is, as shown in FIGS. 5 (a) and 5 (b), an upper surface heating lamp group 3 and a lower surface heating, each of which is composed of a plurality of heating lamps 2, are opposed to the upper and lower surfaces of a semiconductor substrate (hereinafter simply referred to as a wafer) 1. The lamp groups 4 are arranged so as to be orthogonal to each other and are covered with the reflection plates 5 and 6, respectively.

Here, the reason why the heating lamp 2 is used as the rapid heating heat source of the RTP device will be explained. Since the heating lamp 2 utilizes a radiative heat transfer effect, heat generated by convective heat transfer of, for example, conventional gas. This is because it is theoretically suitable for rapid heating, as it does not involve a heating medium, as compared with a heating method using a diffusion action. On the other hand, in general, when forming an oxide thin film, the temperature target of the wafer to be heated is measured because the thin film quality such as the process target value such as thin film thickness, elemental composition and oxide interface properties depends on the heat pattern (temperature rising curve). Is said to be extremely important. As a means for measuring the temperature, contact type temperature measurement using a conventional thermocouple or the like is not preferable because it may cause surface damage of the wafer or contamination of foreign matter.For example, U.S. Pat.
Radiation thermometer 7 described in S.Patent No.4680451
Non-contact direct temperature measurement technology such as (see Fig. 5 (a)) is being used.

[0005]

However, when the surface temperature of the wafer 1 is to be directly measured using the radiation thermometer 7 as described above, the radiation light from the heating lamp 2 becomes noise and the temperature is measured. There is a problem of causing an error. In particular, since silicon wafers also have a wavelength band having a large transmittance for infrared light, the radiated light from the heating lamp group provided on the back surface side of the temperature measurement surface also becomes noise.

To explain this more qualitatively, the characteristics of the spectral sensitivity R of the radiation thermometer and the heating lamp radiation energy spectrum L with respect to the wavelength λ are as shown in FIG. 6 (a), and the wafer 1 is 400 ° C. The spectral transmittance S of silicon in the infrared region with respect to the wavelength λ when heated to the above temperature has the characteristics shown in FIG. 6 (b). As can be seen from these figures, the influence of the heating lamp group on the back surface side of the wafer 1 cannot be ignored.

From this, when the temperature is measured using the radiation thermometer, it is necessary to remove the radiant energy noise of the heating lamp group on the wafer surface side to be measured by the radiation thermometer, and the heating lamp on the opposite side to be measured. It is necessary to remove the radiant energy noise of the group and the stray light such as diffuse reflection noise of the entire RTP device, but it is necessary to take measures such as S / N ratio in the conventional radiation temperature measurement. It was not so high that the temperature measurement accuracy could be reflected in the control.

As in the temperature measuring device disclosed in Japanese Patent Laid-Open No. 63-285428, an infrared light source and a chopper for shielding the infrared light source are provided, and noise is generated due to a difference between measured data in the light-shielded state and in the illuminated state. Although a method of eliminating the influence of 1 has been proposed, this method is disadvantageous in that the constituent elements such as signal processing are complicated because an infrared light source for measurement is particularly required, which is not preferable.

An object of the present invention is to provide a rapid thermal oxidation device for a semiconductor substrate, which solves the problems of the prior art as described above.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a plurality of heating lamp groups are arranged so as to face the upper and lower surfaces of a semiconductor substrate so as to be orthogonal to each other, and a reflector for covering the upper and lower heating lamp groups. A rapid heating lamp device comprising: a radiation thermometer for measuring the temperature of one surface of the semiconductor substrate through an opening formed in one of the reflection plates; and an anti-measurement surface of the semiconductor substrate. A rapid thermal oxidation device for a semiconductor substrate, comprising: a light-shielding shutter which is arranged between the heating lamp group and can be opened and closed so as to shield radiant light from the heating lamp group. The light shielding shutter may have a flat plate shape or a half-sheath shape.

[0011]

[Operation] According to the present invention, when the surface temperature of a wafer is measured by using a radiation thermometer, the reflection plate on the measurement surface side of the wafer is shielded for shielding radiant energy noise from the heating lamp group. In addition to being used as a plate, a light-shielding shutter that blocks radiant light that is a heat source from the heating lamp group is provided on the side opposite to the measurement surface, so that highly accurate temperature measurement that is not affected by noise can be realized. it can.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a side view showing an embodiment of the present invention. The same members as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted. As shown in the figure, a flat light-shielding shutter 8 is provided between the wafer 1 and the lower surface heating lamp group 4,
It is driven in the horizontal direction by the drive motor 9. The drive motor 9 is started / stopped by a light-shielding shutter controller 10. In addition, the reflector 5 on the upper surface is provided with an opening 11 at a position corresponding to the field of view of the radiation thermometer 7.

By thus configuring the RTP device of the present invention, when the temperature of the wafer 1 is measured by the radiation thermometer 7, the drive motor 9 is operated by a command from the light-shielding shutter control device 10. The light-shielding shutter 8 standing by at the position shown in FIG. 2 is horizontally driven to be inserted between the wafer 1 and the lower surface heating lamp group 4. Then, after the heat source from the lower surface heating lamp group 4 is shut off, the measurement of the radiation thermometer 7 is started.

Thus, when the temperature is measured by the radiation thermometer 7, the radiant light transmitted from the back surface side of the wafer 1 to the measurement surface side can be cut off, and the radiation from the upper surface heating lamp group 3 on the measurement surface side can be cut off. Since energy noise can be blocked, accurate temperature measurement with few measurement errors can be performed. Further, when the temperature measurement is completed, the drive motor 9 is operated in the reverse direction again according to a command from the light-shielding shutter control device 10 to return the light-shielding shutter 8 to the position shown in FIG. .

FIG. 3 is a perspective view showing another embodiment, in which the shape of the light-shielding shutter 8 is not a flat plate shape but a half-sheath shape. When heating the wafer 1 with the lower surface heating lamp group 4, as shown in FIG. 4 (a), the opening of the half-sheath light-shielding shutter 8'is directed upward, and at the time of temperature measurement, as shown in FIG. 4 (b). The shading shutter 8'is set to 18 by a drive motor (not shown).
Rotate it 0 ° to face the opening downward. by this,
The same effect as that of the flat light-shielding shutter 8 of FIG. 1 is achieved.

In the above embodiment, the light-shielding shutter 8 or 8'was described as being arranged between the wafer 1 and the lower surface heating lamp group 4, but the present invention is not limited to this, and the upper surface heating lamp group is not limited thereto. It goes without saying that it may be arranged between the wafer 3 and the wafer 1. However, in this case, the measurement surface of the radiation thermometer 7 is on the opposite side.

[0017]

As described above, according to the present invention, when the temperature is measured using the radiation thermometer, noise from the heating lamp group on the measurement surface side of the wafer is blocked and the heating lamp on the non-measurement surface side is provided. Since I tried to shut off the heat source from the group,
It is expected that the measurement accuracy of the wafer surface temperature can be improved, the film formation accuracy of the wafer can be improved, and the yield of LSI products can be greatly improved.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a plan view illustrating the operation of FIG.

FIG. 3 is a perspective view showing only a main part of another embodiment of the present invention.

FIG. 4 is a side view illustrating the operation of FIG.

FIG. 5A is a side view showing a conventional example of an RTP device, and FIG.
FIG.

6A is a characteristic diagram showing a relationship between a wavelength and a radiation thermometer spectral sensitivity / heat lamp radiation energy spectrum, and FIG. 6B is a characteristic diagram showing a relationship between wavelength and a silicon spectral transmittance.

[Explanation of symbols]

 1 Wafer (semiconductor substrate) 2 Heating lamp 3 Upper surface heating lamp group 4 Lower surface heating lamp group 5,6 Reflector 7 Radiation thermometer 8, 8'Shading shutter 9 Drive motor 10 Shading shutter controller 11 Opening part

Claims (3)

[Claims] 1. A rapid heating lamp device comprising a plurality of heating lamp groups which are arranged so as to face the upper and lower surfaces of a semiconductor substrate so as to be orthogonal to each other and a reflecting plate which covers the upper and lower heating lamp groups. A radiation thermometer for measuring the temperature of one surface of the semiconductor substrate through an opening formed in one of the reflection plates, and between the counter measurement surface of the semiconductor substrate and the heating lamp group. A rapid thermal oxidation device for a semiconductor substrate, comprising: a light-blocking shutter that is arranged to be openable and closable to block radiant light from the heating lamp group. 2. The rapid thermal oxidation device for a semiconductor substrate according to claim 1, wherein the light-shielding shutter has a flat plate shape. 3. The rapid thermal oxidation device for a semiconductor substrate according to claim 1, wherein the light-shielding shutter has a half-sheath shape.