JPH07240378A - Semiconductor thin film manufacturing device - Google Patents

Abstract

PURPOSE:To easily correct either the mistaken pattern of a silicon substrate or the errors in measurement of a radiation thermometer resultant from the increase in the film thickness in the film forming step for precisely measuring the substrate surface temperature by calibrating the radiation thermometer by the temperature distribution curve of desorption amount of hydrogen molecules. CONSTITUTION:When a patterned silicon substrate 3 with the surface terminated with hydrogen atoms is heated from about 300 deg.C to 600 deg.C by a heater 2, two peak values of the temperature distribution curve of hydrogen desorption amount attained by a mass spectrometer 7 are 400 deg.C and 500 deg.C. However, it is so far evident that the correct values of these two peaks are to be 425 deg.C and 520 deg.C. Accordingly, the measured values by a radiation thermometer 5 are calibrated to be 425 deg.C and 520 deg.C. Through these procedures, the radiation thermometer 5 can indicate the correct substrate surface temperature thereby enabling a thin film to be grown with excellent reproducibility regardless of the difference in patterns.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor thin film manufacturing apparatus.

[0002]

2. Description of the Related Art In the process of growing a semiconductor thin film, a process utilizing a thermal reaction is often used. Substrate temperature is one of the most influential parameters in the growth of thin films using thermal reaction. Therefore, in order to control these thermal reactions, it is very important to control the temperature of the semiconductor substrate, and an accurate method for measuring the substrate surface temperature is needed. In a conventional process utilizing a thermal reaction, a hot wall furnace having a large heat capacity for heating the entire furnace has been mainly used as a manufacturing apparatus thereof. In this case, if the temperature of the entire furnace is stabilized, the inside of the furnace will be in a thermally equilibrium state, and the temperature of the substrate will be monitored with good reproducibility by measuring the temperature of the furnace using a thermocouple or the like. To be able to
The thermal reaction could be easily controlled.

However, in recent years, for the purpose of cleaning the process and improving accuracy, a process using an ultra-high vacuum with an ultimate vacuum of 10 ⁻⁶ Pa or less has been widely used. In this case, since there is no gas molecule serving as a heat medium in the container and stainless steel is often used as the container, the hot wall furnace cannot be used. Therefore, in this process, a cold wall furnace in which a heater is installed inside the container to directly heat the substrate is used as an apparatus. Since this equipment is not in thermal equilibrium in the furnace, it is not possible to measure the substrate surface temperature easily and accurately as in the case of a hot wall furnace, and there is a problem in controlling the thermal reaction. Has occurred.

Up to now, a radiation thermometer has been widely used as an effective means for measuring the temperature of the substrate surface in an ultrahigh vacuum. This measurement method uses the fact that the spectrum of infrared light emitted from a substance can be expressed as a function of the temperature of the substance, and the infrared intensity emitted from the surface of a heated substance is measured, and this is measured as the temperature. It is to convert. Here, generally, the relationship between the temperature of the substance and the line intensity of the radiated light is unique to the substance and its surface state.

On the other hand, although the selective epitaxial growth technique of silicon has been attracting attention in recent years, the silicon substrate used in such a semiconductor manufacturing process is generally covered with an oxide, a nitride or the like and has a circuit pattern. It is carved, and the crystalline silicon is exposed only in this carved part. That is, there are mixed regions of two or more different substances on the surface of the substrate.

In order to measure the surface temperature of such a substrate with a radiation thermometer, in a conventional apparatus using a cold wall furnace, the relationship between the temperature of the substance and the spectrum of radiant light is determined according to the surface condition. It is necessary to correct again. That is, when using substrates having different circuit patterns, there is no simple correction method, and the correction needs to be performed for each substrate. Further, since the circuit pattern on the surface is not uniform, the reproducibility of the measurement may be affected depending on the position monitored by the radiation thermometer even when the substrates having the same pattern are used.

Further, an unavoidable problem when measuring the temperature by the radiant light from a substance is that the radiant light from the thin film surface formed and the substrate-thin film interface increase as the film thickness increases in the film forming process. The interference of the emitted light causes the temperature value of the radiation thermometer to vibrate. In the process of forming such a film, the accurate substrate surface temperature cannot be measured.

As described above, in a device which cannot measure the substrate surface temperature with good reproducibility, it is difficult to control the temperature of the semiconductor substrate,
There are significant problems in controlling the thermal reaction.

[0009]

As described above, in a device using a conventional cold wall furnace, a silicon substrate having an uneven surface state such as a pattern carved or a film thickness formed by film formation is used. It was very difficult to control the thermal reaction in this step because it was not possible to reproducibly measure the temperature when the temperature changed.

The present invention provides a semiconductor thin film manufacturing apparatus having a function of simply and reproducibly measuring the surface temperature of a silicon substrate in an ultrahigh vacuum, and capable of controlling the thermal reaction used in this step. The purpose is to do.

[0011]

At present, wet etching with HF is often used as a pretreatment of a silicon substrate. The surface of the silicon substrate subjected to this treatment is
It is known to be terminated with atoms. By heating the substrate, H atoms on the surface begin to be desorbed as H ₂ molecules from around 375 ° C, and are completely desorbed around 600 ° C. (Stephen M. Gate, Roderick R. Kunz, C.
Michael Greenlief; Surf. Sci. 207 364 (1989) A semiconductor thin film manufacturing apparatus according to the present invention comprises a substrate having a silicon surface exposed at least at a part thereof, and 375 from this surface.
Equipped with a function to measure the temperature distribution of the desorption amount of hydrogen molecules that are thermally desorbed above ℃, and to have the function of correcting the radiation thermometer for measuring the substrate surface temperature using this temperature distribution curve. It has the characteristic that

[0012]

[Function] By calibrating the radiation thermometer with the temperature distribution curve of the desorption amount of hydrogen molecules, it is possible to easily correct the measurement error of the radiation thermometer due to the difference in the pattern of the silicon substrate and the increase in the film thickness during film formation. can do. This makes it possible to accurately measure the substrate surface temperature and control the thermal reaction during film formation.

[0013]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a semiconductor thin film manufacturing apparatus according to the present invention. Reference numeral 1 in FIG. 1 denotes a vacuum container made of an example of stainless steel, in which a substrate heating heater 2 and a hydrogen-terminated silicon substrate 3 are arranged facing the heater 2. Reference numeral 4 denotes a vacuum pump, for example, a turbo molecular pump, which exhausts the inside of the vacuum container 1. Further, 7 is a mass spectrometer, which can be used to measure the amount of hydrogen molecules desorbed from the substrate surface. Further, the heater 2, the radiation thermometer 5, and the mass spectrometer 7 can be controlled by the controller 8, whereby the temperature distribution curve of the hydrogen desorption amount can be acquired and the reading of the radiation thermometer 5 can be corrected.

By correcting the radiation thermometer by the correction function unit 10 of the controller by the apparatus of the above-described example as described below and enabling accurate surface temperature measurement, the growth of the semiconductor thin film can be performed with good reproducibility. Done. That is, the patterned silicon substrate 3 whose surface is terminated by hydrogen atoms is heated by the heater 2 at about 300 to 600 ° C.
A temperature distribution curve of the amount of desorbed hydrogen obtained by using the mass spectrometer 7 when heated up to is shown in FIG. The temperature value (Tpyro) at this time is measured by a radiation thermometer, and the two peak values of the temperature distribution curve are 400
It can be seen that the temperature is 500 ° C. However, the exact values of these two peaks have so far been found to be 425 ° C and 520 ° C. Therefore, the measured value of the radiation thermometer 5 by the controller 8 is 425 ° C and 520 ° C.
Calibrate so that By this operation, the radiation thermometer showed the correct value of the substrate surface temperature, and it became possible to grow the thin film with good reproducibility regardless of the difference in the pattern.

FIG. 3 shows about 20 layers on the patterned substrate.
The film thickness of 0 nm is about 300 to 600 ℃
The temperature distribution of the amount of hydrogen desorption obtained when heated up to is shown. At this time, the measured values (Tpyro) of the two peaks by the radiation thermometer before calibration are 470 due to the interference of the radiated light.
It can be seen that the temperature shifts to 370 ° C., which is a larger shift than the previous example. In this case, the radiation thermometer also shows the correct value of the substrate surface temperature by performing the calibration by the controller 8. As a result, it becomes possible to accurately measure the substrate surface temperature even in the step after growing a thin film having a thickness that causes interference of emitted light.

In the examples shown above, a mass spectrometer was used to measure the amount of desorbed hydrogen, but when the container 1 is an ultrahigh vacuum device, the base pressure is sufficient to be about 10 ^-6 Pa. Since the temperature is low, hydrogen molecules become the predominant molecular species in the container during the temperature rise of the substrate. Therefore, in this case, the desorption amount of hydrogen can be quantified by using a simpler total pressure vacuum gauge such as an ionization vacuum gauge instead of the mass spectrometer 7. Furthermore, even when the container 1 is not a reduced pressure system such as atmospheric pressure CVD,
The amount of desorbed hydrogen can be quantified by using an atmospheric pressure mass spectrometer.

(Embodiment 2) Another embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a sectional view showing a semiconductor thin film manufacturing apparatus according to the present invention. Reference numeral 1 in FIG. 4 is a vacuum container made of an example of stainless steel, in which a substrate heating heater 2 and a hydrogen-terminated silicon substrate 3 are arranged facing the heater 2. Reference numeral 4 denotes a vacuum pump, for example, a turbo molecular pump, which includes a mechanical booster pump 14 and a rotary pump 2.
At 4 the back pressure is maintained and the inside of the vacuum container 1 is evacuated.

An ionization vacuum gauge 17 is provided to measure the total pressure inside the vacuum container 1. A Pirani vacuum gauge 27 measures the back pressure of the turbo molecular pump 4.

Using the semiconductor thin film manufacturing apparatus of the above example, the silicon substrate 3 whose surface is terminated with hydrogen is placed in the vacuum container 1 as shown in FIG. 4, and heated in the range of 375 ° C. to 600 ° C., and ionized. The total pressure is measured by the vacuum gauge 17 and recorded in the recording device 20 attached. This recording result is illustrated in FIG. This result is nothing but the change in pressure inside the container due to the desorption of hydrogen molecules that reflects the temperature of the substrate surface. Is changing. ” Further, since it has been clarified that the two peak temperatures are 425 ° C. and 520 ° C., it is possible to measure the temperature of the substrate by using them. In an ultra-high vacuum container with a degree of vacuum of about 10 ^-6 Pa, this hydrogen molecule becomes the dominant species.
The desorption amount of hydrogen molecules can be measured by a simple means for measuring the pressure change in the container with the ionization vacuum gauge 17 or the change in the pump back pressure with the Pirani vacuum gauge 27. Also,
Even when the substrate has a non-uniform surface state in which a pattern is engraved on the surface, the desorption of hydrogen molecules corresponds to the surface temperature, and therefore the surface temperature can be measured with good reproducibility.

[0022]

As described above, according to the present invention, it is possible to easily correct the measurement error of the radiation thermometer due to the difference in the pattern and the interference of the emitted light, and it is possible to manufacture the semiconductor thin film with good reproducibility. There is a significant advantage of being possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a semiconductor thin film manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change in the amount of desorbed hydrogen molecules as the temperature of a hydrogen-terminated patterned silicon substrate increases. Where T
Pyro is the value measured by the radiation thermometer before correction, T'pr
yo = Tsub is a corrected radiation thermometer measurement value (true substrate surface temperature).

FIG. 3 is a diagram showing a change in the amount of desorbed hydrogen molecules with temperature rise of a silicon substrate on which a thin film having a thickness of about 200 nm is grown. Tpyro and T'pyro = Tsub are the same as in FIG.

FIG. 4 is a sectional view of a semiconductor thin film manufacturing apparatus according to another embodiment of the present invention.

FIG. 5 is a diagram showing a change in the degree of vacuum in the vacuum container with a change in the temperature of the substrate.

[Explanation of symbols]

 1 vacuum container 2 heater for heating substrate 3 substrate 4, 14, 24 vacuum pump 5 radiation thermometer 6 viewport 7 mass spectrometer 8 controller 17 ionization vacuum gauge 27 Pirani vacuum gauge 20 recording device

Claims (2)

[Claims] 1. A vacuum container; a substrate heating heater provided in the vacuum container; a substrate having a hydrogen-terminated silicon surface exposed at least partially facing the substrate heating heater. A radiation thermometer for measuring the surface temperature of the substrate; a hydrogen molecule partial pressure measuring function unit for obtaining a temperature distribution curve of hydrogen molecules leaving the hydrogen-terminated silicon surface; and a hydrogen molecule partial pressure measuring function unit. A semiconductor thin film manufacturing apparatus, comprising: a controller having a correction function unit that corrects a measurement error of the radiation thermometer based on the obtained temperature distribution curve. 2. A vacuum container, a heater for heating the substrate provided in the vacuum container, a controller for adjusting the temperature of the heater for heating the substrate, and at least a part of the heater arranged to face the heater for heating the substrate. A substrate having a hydrogen-terminated silicon surface exposed to the inside, an exhaust device for exhausting the inside of the vacuum container to a high vacuum degree in which the partial pressure of hydrogen molecules thermally released by the temperature rise of the substrate controls the total pressure, and the substrate To 375 ° C
A semiconductor thin film comprising: a vacuum gauge for heating the above and measuring the degree of vacuum in a vacuum container corresponding to the temperature distribution; and a functional unit for converting a total pressure value measured by the vacuum gauge into a surface temperature. Manufacturing equipment.