JP2005223181A - Method for calculating substrate temperature data and vapor phase growth apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase growth apparatus which can accurately keep track of a temperature state on the surface of each substrate to control a growth temperature for film thickness distribution or lattice crystal, and to grow a high quality of uniform crystal. <P>SOLUTION: In the vapor phase growth apparatus for placing a plurality of substrates on a rotary susceptor within a reactor and growing a thin film on each substrate by vapor phase growth, calculation is carried out over continuously measured temperature data with use of a substrate phase calculated from the rotational speed of the rotary susceptor and a placed substrate position to extract only the temperature of each substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor device manufacturing apparatus in which a plurality of substrates are installed on a rotary susceptor in a reaction furnace, and a thin film is vapor-phase grown on each substrate. The present invention relates to a vapor phase growth apparatus that performs temperature control using a calculation method and a calculation result for data obtained by continuously measuring the above.

In semiconductor device manufacturing, an MOCVD apparatus (Metal Organic Chemical Vapor Deposition) is used for epitaxial growth for forming a thin film on a substrate. As a mechanism of the MOCVD apparatus, there is a general method in which a rotating susceptor having a rotating mechanism is provided in a reaction furnace, a plurality of substrates are placed on the susceptor, and a thin film crystal is grown while rotating. In vapor phase growth, the growth temperature on the substrate is one of the important parameters for growing high-quality crystals with uniform film thickness distribution and lattice crystals, and how to control the growth temperature is important. Become. In order to control the growth temperature, the temperature state of each substrate surface must be measured as accurately as possible. Conventionally, as a method for measuring the surface temperature of a substrate in a vapor phase growth apparatus using a rotary susceptor, there has been a method using a pyrometer (thermal radiation thermometer). As a method of measuring the temperature of a plurality of substrates installed on a rotating susceptor in a reaction furnace with this pyrometer, it is common to fix the position of the pyrometer and measure in the following two measurement modes. One is temperature measurement in a continuous mode that continuously measures the substrate surface temperature, which changes position every time due to the rotation of the susceptor, at a fixed position, and the other is to extract the maximum temperature from the measured substrate surface temperature. This is a temperature measurement in the maximum temperature display mode that displays only the maximum temperature. Also, the timing for measuring the temperature is appropriately determined based on the position detection signal of each substrate on the rotary susceptor and the information on the arrangement pattern and the number of rotations of the substrate, and only when the substrate on the susceptor arrives at the measurement position. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 11-79887

  However, the temperature measurement method using the continuous mode has a drawback in that the surface temperature state of the substrate cannot be accurately grasped. Since the position of the pyrometer is fixed, the locus of the location measured by the pyrometer on the susceptor is a concentric circle with the rotation axis as the center. In order to measure the temperature of the substrate, it is necessary to determine the measurement location of the pyrometer so that the locus to be measured similarly follows the center of the substrate arranged concentrically. However, since the board | substrate arrange | positioned on a susceptor is not closely_contact | adhering, the locus | trajectory to measure exists in the location which passes a susceptor other than a board | substrate. Therefore, when the temperature measurement is performed in the continuous mode, the measurement data includes the susceptor temperature in addition to the substrate temperature, and it is difficult to grasp only the substrate temperature. In the temperature measurement method using the maximum temperature display mode, the maximum temperature during one rotation of the susceptor can be known, but the temperature of each substrate cannot be measured, and the obtained data is also discontinuous. It will be a thing. Also in the method of performing measurement only when the substrate on the susceptor arrives at the measurement position, the obtained temperature data is discontinuous. In view of the above problems, the present invention provides a substrate temperature data calculation method capable of extracting only a substrate temperature from continuously measured temperature data in a vapor phase growth apparatus using a rotary susceptor, and this calculation method. The present invention provides a vapor phase growth apparatus that uses it to perform substrate temperature control.

  In order to solve the above problems, the substrate temperature data calculation method according to the present invention includes a pyrometer in the case where a plurality of substrates are installed on a rotary susceptor in a reaction furnace and a thin film is vapor-phase grown on each substrate. The substrate temperature data continuously measured by the above and the substrate phase data obtained from the substrate arrangement pattern and the number of rotations are overlapped to calculate the temperature data of only the substrate. Further, the vapor phase growth apparatus of the present invention performs temperature control by feeding back to the apparatus the temperature information obtained by the data processing apparatus and the data processing apparatus that accurately measure the substrate temperature using the calculation method according to the present invention. It has a configuration.

  As described above, the present invention superimposes the substrate temperature data continuously measured by the pyrometer and the phase data of the substrate obtained from the substrate arrangement pattern and the rotation speed, and calculates the temperature data of only the substrate, It is possible to accurately grasp each substrate temperature information of a vapor phase growth apparatus having a rotary susceptor and contribute to vapor phase growth of a higher quality thin film having a uniform film thickness distribution, lattice crystal, etc. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic explanatory view of a MOCVD apparatus. In this embodiment mode, a face-down type MOCVD apparatus (the substrate surface is positioned below during vapor phase growth) is used. In the MOCVD apparatus, a compound semiconductor substrate 4 such as GaAs is installed on a susceptor 2 and heated to a predetermined temperature using a heater 1. A raw material organic metal or hydride gas is supplied to the surface of the substrate 4 to cause a chemical reaction. A desired compound semiconductor single crystal thin film such as AlGaAs is grown. As shown in FIG. 2A, six substrates 4 on the susceptor 2 in the present embodiment are set so as to be installed in a concentric circle having the susceptor 2 rotation axis as a center at predetermined intervals of 60 °. Further, when performing vapor phase growth, the susceptor 2 is rotated at a speed of 5 rpm by a motor 5 to make the thickness of the grown thin film uniform. The pyrometer 3 is fixedly installed on the side facing the susceptor 2 and constantly measures the temperature of the growing substrate 4 through a viewing window provided on the facing surface. At the time of measurement, the sampling period of the pyrometer 3 is set to about 1 ms. Since the pyrometer 3 measures a fixed position with respect to the rotating susceptor 2, the measurement point of the pyrometer 3 viewed from the susceptor 2 is centered on the center of the susceptor 2 as shown by the locus 6 shown by the dotted line in FIG. It will be a concentric circle. The temperature data measured in this embodiment is as shown by the waveform 11 in FIG. Since the pyrometer 3 continuously measures at a sampling period of 1 ms, the pyrometer 3 becomes data including the temperature of the susceptor 2 part in addition to the substrate 4. In FIG. 3, the range 16 is the temperature at which the substrate 4 is measured, and the range 17 is the temperature at which the susceptor 2 is measured. With this data, it is difficult to accurately know the temperature data of only the substrate 4. Therefore, only the substrate 4 temperature is extracted by the calculation method described below. First, the rotational speed of the susceptor 2 is output from the MOCVD apparatus. The rotational speed of the susceptor 2 can be easily obtained from the output of the motor 5 that rotates. Since the susceptor 2 rotates, the locus of the center position of each substrate 4 installed on the susceptor 2 is also a concentric circle with the rotation axis as the center. The phase of the substrate 4 is expressed as follows: suppose the rotational speed of the susceptor 2 is ω, and the distance A from the center of the susceptor 2 to the center of the substrate 4
Phase: Asin (ωt + α) α: Obtained by a constant.

Since the six substrates 4 (referred to as a1 to a6) are installed at a predetermined interval of 60 °, the phase of each substrate 4 is respectively
a1: P1 = Asin (ωt + 2π (60 × 1/360) + α) (1)
a2: P2 = Asin (ωt + 2π (60 × 2/360) + α) (2)
...
a6: P6 = Asin (ωt + 2π (60 × 6/360) + α) (6)
It is represented by When the phase of the substrate 4 is schematically illustrated, a waveform 12 in FIG. 3 is obtained. If the phase reference is defined as shown in FIG. 2B, the phase range R in which the temperature is measured by the pyrometer 3 is determined from the constants L to A> determined by the distance from the center of the susceptor 2 to the center of the substrate 4. R> L. For phase equation (1) of substrate a1
When Asin (ωt + 2π (60 × 1/360) + α)> L P1 = 1
When Asin (ωt + 2π (60 × 1/360) + α) <L P1 = 0
When the above conversion is performed, the phase of a1 becomes a pulse waveform shown by the waveform 13 in FIG. When the pulse waveform obtained by this conversion and the temperature data of the pyrometer 3 are superposed, the waveform 14 shown in FIG. 3 is obtained, which can be converted into data only for the substrate temperature a1. Similarly, by performing this calculation for the substrate temperature data a2 to a6, it is possible to extract only the substrate temperature from the continuous data including the measured temperature of the susceptor 2 part, and to know each substrate temperature accurately. Can do. In addition, a data processing device 7 is provided for extracting substrate temperature data by this calculation method for substrate temperature data output from the vapor phase growth apparatus, and temperature information is transferred from the data processing apparatus to the vapor phase growth apparatus by the control device 8. It is configured to provide feedback. The output of the heater 1 is controlled based on the substrate temperature data fed back from the data processing apparatus to the vapor phase growth apparatus, and the substrate temperature is stabilized. By using the vapor phase growth apparatus of this configuration, the film thickness distribution and the uniformity of the lattice crystal are excellent, and higher quality vapor phase growth can be performed.

  In this embodiment, the example in which the compound semiconductor single crystal thin film is grown on the compound semiconductor substrate has been described. However, the present invention is not limited to this, and the compound semiconductor is formed on a Si substrate, a glass substrate, a ceramic substrate, or the like. The present invention can also be applied to the case of growing a semiconductor other than the above or a thin film such as an oxide or metal other than the semiconductor. Although the MOCVD method is used as an example of the vapor phase growth method, the present invention is not limited to this, and can be applied to vapor phase growth methods such as chloride CVD, halide CVD, vapor deposition, and molecular beam epitaxy (MBE). is there.

  Further, the number and arrangement pattern of the substrates installed on the susceptor are not limited to those in which six substrates are arranged every 60 degrees as in the above embodiment, and an arbitrary number of substrates can be arranged in a predetermined pattern. The present invention can also be applied to vapor phase growth.

  The substrate temperature data calculation method and vapor phase growth apparatus according to the present invention is a vapor phase growth apparatus having a rotary susceptor such as a MOCVD apparatus in semiconductor manufacturing. It is useful as a calculation method and a vapor phase growth apparatus for data obtained by continuously measuring each substrate temperature with a pyrometer for vapor phase growth.

The block diagram showing the vapor phase growth apparatus in embodiment of this invention The figure showing the board | substrate installation position on a susceptor in embodiment of this invention. The figure which shows the calculation waveform of the substrate temperature data in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater 2 Susceptor 3 Pyrometer 4 Board | substrate 5 Motor 6 Trajectory 7 Data processing apparatus 8 Control apparatus 11 Waveform 12 Waveform 13 Waveform 14 Waveform 16 Range 17 Range

Claims (3)

In a vapor phase growth apparatus in which a plurality of substrates are installed on a rotary susceptor in a reaction furnace, and a thin film is vapor-phase grown on each substrate,
Substrate temperature data that is obtained by performing an operation on the continuously measured temperature data using the substrate phase calculated from the rotational speed of the rotary susceptor and the substrate installation position, and extracting only the temperature of each substrate. Calculation method. A vapor phase growth apparatus comprising: data processing means for executing the calculation method according to claim 1; and temperature control means for controlling the temperature of the apparatus based on temperature data obtained from the data processing means. A process of performing data processing on the temperature data output from the vapor phase growth apparatus using the calculation method according to claim 1 and a step of performing temperature control by feeding back the obtained temperature data to the vapor phase growth apparatus. A vapor phase growth method comprising:

Images