JPH03252127A - Temperature control method for vapor growth device - Google Patents

Abstract

PURPOSE:To correct the nonuniformity of temperature distribution on a susceptor with high accuracy, and to control the temperature correction of a wafer precisely by burying a thermocouple sealed by an insulator into a susceptor, measuring temperature distribution in the susceptor, changing the calorific values of the lamps of each group of a heat source and equalizing temperature distribution. CONSTITUTION:In a vapor growth device in which semiconductor substrates 21 are heated by lamps 23 and vapor growth is conducted, thermocouples 24 sealed by insulators are buried into a susceptor 22 supporting or heating the semiconductor substrates 21, temperature distribution in the susceptor 22 is measured, a large number of the lamps 23 in a heat source are divided and set previously to a required number of groups, and the calorific values of each group of the lamps 23 are changed according to temperature distribution measured and temperature distribution in the susceptor 22 is equalized. The thermocouples 24 are buried to each section of the upper section, intermediate section and lower section of the susceptor 22, temperature distribution is determined, the heating and cooling of the required region of the susceptor 22 are decided on the bases of the temperature distribution, an output to the heating lamp faced oppositely to a section, which must be heated, is increased, and an output to the heating lamp faced oppositely to a section, which must be cooled, is reduced.

Description

[Detailed Description of the Invention] Field of Application This invention relates to a method of controlling the heating temperature of a susceptor of a vapor phase growth apparatus for growing a thin film by vapor phase growth on a semiconductor substrate, and the invention relates to a method for controlling the heating temperature of a susceptor for supporting or heating the semiconductor substrate. Temperature control of vapor phase growth equipment by embedding a thermocouple in the susceptor, directly measuring the temperature, adjusting the heating source, making the temperature distribution uniform, and accurately controlling the temperature correction of wafers within the same equipment and between equipment. Regarding the method.

Conventional technology Today, horizontal furnaces, vertical furnaces, and barrel furnaces are typical for vapor phase growth equipment used for epitaxial growth on semiconductor substrates, and resistors, high-frequency coils, infrared lamps, etc. are used as heating sources. There is.

For example, a vertical furnace vapor phase growth apparatus that uses an infrared lamp as a heating source has a structure in which a semiconductor substrate is placed inside a dome-shaped reaction chamber and a disk-shaped susceptor is placed along the outer surface of the dome. The entire susceptor inside the reaction chamber is heated by radiation using an infrared lamp.

The susceptor is mainly made of a carbon base coated with silicon carbide, and is heated directly by the heating source or by radiant heat.

Vapor phase growth requires uniform temperature distribution within the reaction chamber, especially within the susceptor, and the temperature of the susceptor is measured with a radiant temperature needle attached to a metal chamber surrounding the reaction chamber. The reaction temperature is controlled by adjusting the output to the reactor.

Additionally, measures have been taken in which a temperature measuring base made of the same material as the susceptor is provided around the susceptor and the temperature of the base is measured with a thermocouple to control the temperature of the susceptor.

However, if the characteristics of the thin film on the semiconductor substrate are required to be high, high precision is required for temperature uniformity within the reaction chamber, which has been difficult to meet with conventional methods.

In the method described above, in which the temperature of the susceptor is measured and controlled using a radiation thermometer, the temperature is measured from outside the reaction vessel, so the more the reaction vessel becomes dirty and the light transmittance decreases, the more the measurement error occurs. There is a problem in that accurate measurement becomes difficult due to the increase in the amount of light and disturbance of light within the reaction apparatus.

Furthermore, radiation thermometers cannot accurately measure the temperature range from room temperature to several hundred degrees.

The method of measuring the temperature of the temperature measurement base material placed around the susceptor measures a temperature different from the actual temperature of the susceptor, and cannot measure the temperature distribution on the susceptor that supports the semiconductor substrate. First, the temperature distribution within the susceptor cannot be made uniform with high precision.

Therefore, slips may occur due to non-uniformity in the temperature distribution within each substrate, differences in thin film quality between wafers may occur due to non-uniformity in temperature distribution on the same susceptor, or differences in thin film quality between wafers or between vapor phase growth equipment. There were problems such as not being able to correct the temperature.

The present invention provides a temperature control method that can correct non-uniformity of temperature distribution on a susceptor with high accuracy in a vapor phase growth apparatus, and that can accurately control temperature correction of wafers within the same vapor phase growth apparatus and between other apparatuses. intended to provide.

Summary of the Invention The present invention was developed as a result of various studies on temperature measurement methods and heating source control, with the aim of creating a temperature control method that can correct the non-uniformity of temperature distribution on a susceptor with high precision. By embedding a sealed thermocouple to directly measure the temperature distribution inside the susceptor and feeding this back to control the heat output of the heating source, the temperature can be measured at the point closest to the semiconductor substrate being vapor-phase grown. This invention was completed based on the finding that accurate temperature control is now possible, and that temperature correction of wafers within the same device and between devices can be accurately controlled.

That is, the present invention provides a vapor phase growth apparatus such as a horizontal furnace, a vertical furnace, or a barrel furnace that performs vapor phase growth by heating a semiconductor substrate with a lamp, in which a susceptor that supports or heats the semiconductor substrate is made of an insulator. A sealed thermocouple is embedded to measure the temperature distribution inside the susceptor, and the numerous lamps serving as the heating source are divided into the required number of groups in advance.
This is a temperature control method for a vapor phase growth apparatus, characterized in that the heat generation amount of each group of lamps is changed in accordance with the measured temperature distribution to make the temperature distribution in the susceptor uniform.

The present invention also provides a vertical vapor phase growth apparatus in which a high frequency induction coil is disposed on the back side of a rotary table type susceptor to heat a semiconductor substrate and perform vapor phase growth, wherein the inside of the susceptor is sealed with an insulator. The temperature distribution inside the susceptor is measured by embedding a thermocouple in the susceptor, allowing multiple high-frequency induction coils to approach and leave the susceptor individually, and changing the distance between each coil and the susceptor according to the measured temperature distribution. This is a temperature control method for a vertical vapor phase growth apparatus characterized by making the temperature distribution uniform.

DISCLOSURE OF THE INVENTION BASED ON DRAWINGS FIG. 1 is a schematic explanatory diagram of a vertical vapor phase growth apparatus to which the present invention is applied, and FIG. 2 is a longitudinal cross-sectional explanatory diagram of a main part of a susceptor.

FIG. 3 is a schematic explanatory diagram of a barrel type vapor phase growth apparatus to which the present invention is applied.

Denya 1 As shown in Figure 1, the vertical vapor phase growth apparatus has a table-shaped susceptor (2) on which a semiconductor substrate (3) is placed in a dome-shaped reaction vessel (1) rotatably arranged. A high-frequency oscillation coil (4) for heating is provided below the susceptor (2), and a semiconductor gas is introduced and ejected from a semiconductor gas injection nozzle (5) disposed through the center of the susceptor (2). After the vapor phase growth reaction is performed at the top, the reaction gas is discharged from a gas exhaust port (6) provided at the bottom.

As shown in FIG. 2, a plurality of thermocouples (10) are embedded in the susceptor (2) and sealed with an insulator (11).

The number of thermocouples (10) and the location where they are buried are determined by the susceptor (2).
When burying, for example, the wiring part of the thermocouple (10) except the contact part is covered with an insulating tube, and the whole is covered with a tube-shaped insulating tube. It is sealed with a body (11) and buried so as not to be affected by the external atmosphere.

Since the susceptor (2) rotates, electrical connections between the thermocouple (10) and external measuring instruments and computing units are made through a sealed rotary joint.

On the other hand, although not shown, the high-frequency oscillation coils (4) provided below the susceptor (2) are configured so that each of the plurality of coils can be moved up and down individually, and are opposed to each other by approaching and away from the susceptor (2). The interval can be adjusted arbitrarily.

Effect: The semiconductor substrate (3) is supported by the susceptor (2) and heated together with the susceptor by the high frequency oscillation coil (4). During the vapor phase growth, a plurality of thermocouples (10) embedded in the susceptor (2) measure the temperature inside the susceptor (2),
The measurement signal is input to the control calculator, and the susceptor (
2) The temperature distribution within can be grasped.

Based on the obtained temperature distribution inside the susceptor (2), the heating and cooling of the required area of the susceptor (2) is determined, and the high frequency oscillation coil (4) near the area to be heated is determined accordingly.
) close to the susceptor (2), and conversely, by moving the high frequency oscillation coil (4) away from the area to be cooled,
The temperature distribution within the susceptor (2) can be made uniform.

Even when maintaining the predetermined temperature during vapor phase growth, the temperature uniformity within the susceptor (2) can be maintained within a deviation of 1 to 3° C. whether the temperature is rising or falling.

The barrel-type vapor phase growth apparatus shown in FIG. 3 includes, for example, a substantially polygonal pyramid-shaped susceptor ( 22) are housed vertically, and the reaction gas is introduced from the upper circumferential side of the reaction chamber (20) and led out from the lower center, and an infrared lamp (23 ) are arranged in layers, and the susceptor (22) is heated by radiation.

A thermocouple (24) as a temperature sensor is sealed with an insulator and buried in the outer peripheral surface of the susceptor (22), and here, it is buried in each of the upper, middle, and lower parts of the susceptor (22).

The infrared lamp (23) serving as the heat source is divided into a required number of groups in advance, and the output of the heating lamp can be controlled by, for example, controlling the voltage or current of the lamp driver for each group.

As in Effect Configuration 1, the temperature distribution within the susceptor (22) is always grasped by the embedded thermocouple (24).

Based on the temperature distribution, heating or cooling of the required area of the susceptor (22) is determined, and the output to the heating lamp facing the area requiring heating is increased, and the output to the heating lamp facing the area requiring cooling is increased. By reducing the power output to the heat lamps present, the temperature distribution within the susceptor (22) can be equalized.

Effects of the Invention According to the temperature control method of the present invention, it is possible to prevent damage caused by light disturbance in a device such as a conventional radiation thermometer, dirt in a reaction vessel, etc.
The measured temperature does not become inaccurate, and the temperature can be monitored from the initial stage of heating to the steady state temperature.

Furthermore, since the distribution in the vicinity of the semiconductor substrate on which vapor phase growth is to be performed can be accurately determined, growth can be easily controlled based on temperature distribution.

Furthermore, temperature correction of wafers within the same vapor phase growth apparatus and between apparatuses can be accurately controlled.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory view of a vertical vapor phase growth apparatus to which the present invention is applied, and FIG. 2 is a longitudinal cross-sectional view of the main part of a susceptor. FIG. 3 is a schematic explanatory diagram of a barrel type vapor phase growth apparatus to which the present invention is applied. DESCRIPTION OF SYMBOLS 1... Reaction container, 2... Susceptor, 3... Semiconductor substrate, 4... High frequency oscillation coil, 5... Injection nozzle, 6... Gas exhaust port, 10... Thermocouple, 11...
- Insulator, 20... Reaction chamber, 21... Semiconductor substrate,
22... Susceptor 23... Infrared lamp, 24...
··thermocouple.

Claims (1)

[Claims] 1. In a vapor phase growth apparatus that performs vapor phase growth by heating a semiconductor substrate with a lamp, a thermocouple sealed with an insulator is embedded in a susceptor that supports or heats the semiconductor substrate, and a thermocouple sealed with an insulator is embedded in the susceptor. The temperature distribution of the heating source is measured, the numerous lamps of the heating source are divided into the required number of groups, and
A temperature control method for a vapor phase growth apparatus, characterized in that the temperature distribution within a susceptor is made uniform by changing the amount of heat generated from each group of lamps according to the measured temperature distribution. 2. In a vertical vapor phase growth apparatus that heats a semiconductor substrate and performs vapor phase growth by disposing a high frequency induction coil on the back side of a rotary table type susceptor, a thermocouple sealed with an insulator is inserted into the susceptor. Embedded, measures the temperature distribution inside the susceptor, allows multiple high-frequency induction coils to move closer to and away from the susceptor individually, and equalizes the temperature distribution inside the susceptor by changing the distance between each coil and the susceptor according to the measured temperature distribution. A temperature control method for a vertical vapor phase growth apparatus, characterized in that: