JP3355475B2 - Substrate temperature distribution measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a temperature distribution of a substrate mounted on a rotary susceptor provided in a reactor for vapor-phase growth of a thin film.

[0002]

2. Description of the Related Art In vapor phase growth, which is a type of epitaxial growth method for forming a thin film on a substrate, the growth temperature on the substrate is increased in order to grow a high-quality crystal having a uniform thickness distribution, specific resistance distribution, and the like. Is one of the important parameters.

In the vapor phase growth method, a rotary susceptor having a rotating mechanism is provided in a reaction furnace so that the concentration and flow of a source gas are uniform on a plurality of substrate surfaces, and a plurality of substrates are mounted on the susceptor. There is a method in which a thin film crystal is grown while being mounted and rotated.

In such a vapor phase growth method as well, how to control the growth temperature has a significant effect on the quality of the grown crystal. Therefore, there is a demand to know the temperature distribution of the substrate on the susceptor as accurately as possible. is there.

[0005] The rotary susceptor has an internal gear along the circumference, and is connected to a drive source such as an electric motor so as to be rotatable. A predetermined number of external gears that engage with the internal gears along the circumference, are formed in a disk shape on which a substrate can be placed, and are configured to rotate along the internal gears of the revolving susceptor. A so-called revolving type susceptor comprising the above-mentioned rotation susceptor has been developed.

According to the self-revolving susceptor, the substrate mounted on the self-rotating susceptor is revolved at a predetermined speed with the rotation of the self-rotating susceptor, and is rotated at a predetermined speed with the rotation of the self-rotating susceptor itself. Since each substrate is introduced, each substrate can be circulated in the reaction furnace heated by the heater without bias, and there is an advantage that the substrate can be easily heated uniformly.

Conventionally, as a method for measuring the temperature of the substrate surface in a vapor phase growth apparatus using the above-described revolving susceptor, there has been a measuring method using a thermal radiation thermometer.

[0008] As a temperature measuring method using this thermal radiation thermometer, a so-called continuous mode is used in which the position of the thermal radiation thermometer is fixed and the substrate surface temperature, which changes every moment due to the rotation of the susceptor, is continuously measured at the fixed position. It was common to measure.

For example, when the center of each rotation susceptor passes through a thermal radiation thermometer, the temperature difference between the rotation susceptor and the revolution susceptor is large. become.

That is, in the graph in which the horizontal axis represents time and the vertical axis represents temperature, the temperature shows a pattern in which the temperature of the rotation susceptor is higher than that of the revolution susceptor, but at least the substrate mounted on the rotation susceptor. It was possible to measure the temperature at the center of the.

[0011]

However, according to the temperature measurement method in the continuous mode, the temperature distribution at the center of the substrate mounted on the rotation susceptor can be measured, but the temperature distribution of the entire substrate is measured. I couldn't.

That is, when the rotation susceptor rotates in the rotation-revolution type susceptor, each part of the substrate on the rotation susceptor shifts on a predetermined trajectory (trochoid curve) corresponding to the rotation speed with time. Therefore, it has been difficult to grasp the temperature of each part with a thermal radiation thermometer provided at a predetermined position in the reaction furnace and measure the temperature distribution over the entire substrate surface.

The present invention has been devised to solve the above-mentioned problems of the prior art, and has a temperature distribution of a rotating substrate in a reaction furnace for vapor-phase growth of a thin film on the substrate. It is an object of the present invention to provide a temperature distribution measuring method capable of accurately measuring the temperature distribution.

[0014]

In order to achieve the above object, the present invention provides a method for measuring the temperature distribution of a substrate mounted on a rotary susceptor provided in a reactor for vapor-phase growth of a thin film. The temperature of the substrate placed on the rotating susceptor is continuously measured by a temperature measuring unit provided at a predetermined position, and the temperature of the substrate is measured with the rotation of the susceptor based on information on the number of rotations of the susceptor. Analyzing the trajectory of the measurement points of the substrate that shifts, and calculating the temperature distribution on the substrate surface by associating the temperature data measured by the temperature measurement means with each measurement point based on the analysis result. did.

In the above-mentioned method for measuring the temperature distribution of a substrate, the rotary susceptor has an internal gear along the circumference, and is connected to a driving source so as to be rotatable. An external gear that engages with the internal gear of the revolution susceptor is formed along the circumference, is formed in a disk shape on which a substrate can be placed, and rotates along the internal gear of the revolution susceptor. The temperature measuring means may be provided so as to face a predetermined position on each of the rotation susceptors through which the substrate passes.

Further, the trajectory of the measurement point is analyzed by assuming that the distance from the center of the revolution susceptor to the center of the rotation susceptor is R, the radius of the rotation susceptor is r, the angular velocity of the revolution susceptor is W, and the angular velocity of the rotation susceptor is w. When the measurement point is represented on the r-θ coordinate with the center of the rotation susceptor taken as the origin, the starting point (0 seconds) is when the center of the substrate on the rotation susceptor coincides with the position of the temperature measuring means. Time)
If the position of (r (t), θ (t)) is measured after t seconds, the position is expressed as: r (t) = 2R sin (wt / 2) θ (t) = (w−W / 2) The calculation may be performed by using two expressions of t.

Further, in the above temperature distribution measuring method, the temperature measuring means may be provided so as to face a position on the rotation susceptor where the center of the substrate passes.

According to the present invention, the temperature distribution of the substrate can be measured in a reactor for vapor-phase growth of a thin film on the substrate, so that the crystal growth temperature can be appropriately controlled. This can contribute to vapor-phase growth of a higher quality thin film having a uniform thickness distribution, specific resistance distribution, and the like.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an example of an embodiment of the present invention will be described with reference to the drawings.

FIGS. 2 and 3 show a method for measuring the temperature distribution of a substrate according to the present invention.
FIG. 3 is a schematic explanatory diagram when applied to epitaxial growth by emical vapor deposition (MOCVD method).

A compound semiconductor substrate a, b, c, d such as GaAs placed on the susceptor 1 is heated to a predetermined temperature by a heating means (not shown), and a raw material organic metal or hydride gas is supplied to the substrate surface. And chemically reacting the desired InGaAs
And growing a compound semiconductor single crystal thin film.

As shown in FIG. 3, the susceptor 1 comprises a revolution susceptor 1A and four rotation susceptors 1B.

A fixed rotation gear 2 as an internal gear is fixedly provided around the revolution susceptor 1A along the circumference of the revolution susceptor 1A.

Further, each rotation susceptor 1B is provided with an external gear that engages with the rotation introducing fixed gear 5.

Although not shown in the drawing, a dish-shaped carbon tray on which the substrates a, b, c and d are placed can be placed on the upper surface of each rotation susceptor 1B.

In the present embodiment, the susceptor 1
A hole 3 for position detection is provided on a disk 3 mounted in parallel with the susceptor 1 on a rotation shaft of the light emitting device, and a position detecting means including a light emitting element 5 and a light receiving element 6 is provided.

The radiation thermometer 7 is located at a point on the rotation center trajectory on the rotation susceptor 1B or in the vicinity thereof (for example, within a radius of the substrate from one point on the rotation center trajectory).
Is fixed.

The measurement result by the radiation thermometer 7 is transmitted to, for example, a control device (not shown) and stored in a storage device as temperature data, displayed on a display, or printed out by a printer. You can also.

The above is the schematic configuration of the reactor to which the method for measuring the temperature distribution of a substrate according to the present invention is applied. Next, the procedure for measuring the temperature in this reactor will be briefly described.

First, the substrates a to d are placed on each of the rotation susceptors 1B via a carbon tray.

Next, the revolution susceptor 1A is rotated at a predetermined rotation speed (for example, 3 rpm) (at the same time, the rotation susceptor 1B is also guided by the rotation introduction fixed gear 2 and starts to rotate at a predetermined speed). The heating by means and the supply of the source gas are started.

At the same time, continuous measurement of the substrate surface temperature by the radiation thermometer 7 is started.

The temperature data measured by the radiation thermometer 7 is transmitted to the control device, and is subjected to predetermined data processing in accordance with the rotation speed of the rotation susceptor 1B, whereby each of the substrates a to d is processed.
The above temperature distribution can be obtained.

Here, a method of obtaining the temperature distribution of the substrate from the temperature data will be briefly described.

First, the revolution susceptor 1A and the rotation susceptor 1
FIG. 4 shows the positional relationship of B.

In FIG. 4, R represents the distance from the center O1 of the revolution susceptor to the center O2 of the revolution susceptor, r represents the radius of the revolution susceptor, W represents the angular velocity of the revolution susceptor, and w represents the angular velocity of the revolution susceptor.

Here, in order to analyze the trajectory of the measurement point on the rotation susceptor 1B by the radiation thermometer 7, the measurement point is represented by r-θ coordinates with the center of the rotation susceptor 1B taken as the origin (0, 0). In other words, the time point when the center of the rotation susceptor 1B coincides with the position of the radiation thermometer 7 is defined as the start point of the temperature measurement (0 second).

When the position of (r (t), θ (t)) after t seconds is specified, the position can be obtained by the following equations (1) and (2).

R (t) = 2R sin (wt / 2) Equation 1 θ (t) = (w−W / 2) t Equation 2 The calculated value is sequentially plotted on the above r-θ coordinates. By doing so, the trajectory of the measurement point on the rotation susceptor having a predetermined correlation with the rotation speed of the rotation susceptor can be accurately known for each elapsed time.

Therefore, by associating the temperature data continuously measured by the radiation thermometer 7 with respect to the locus of the measurement point for each elapsed time, it is possible to know at least the temperature change on the locus of the measurement point. Therefore, based on the temperature change on the locus of the measurement point, it is possible to measure the temperature distribution over the entire surface of the substrate by analogy.

In particular, as shown in FIGS. 6 and 7, by increasing the number of rotations of the rotation susceptor 1B, the locus of the measurement point passes through each part of the substrate surface, so that the temperature distribution can be accurately measured. Will be able to

Here, the locus of the measurement point will be described with reference to FIGS.

FIG. 5 is an explanatory view showing that the trajectory of the measurement point has a rotation speed dependency, that is, the trajectory of the measurement point changes depending on the rotation speed of the rotation susceptor.

In the case of FIG. 5, the temperature measurement condition is R
= 13 cm, r = 6 cm, revolution number of revolution susceptor: K is 3 rpm, revolution number of rotation susceptor: k is 10 rpm,
It was changed in four stages of 30 rpm, 100 rpm, and 300 rpm.

In this case, the angular velocity of the revolution susceptor: W
Is given by a calculation formula of W = 360 * 3/60/2 * π (rad / sec), and the angular velocity w of the rotation susceptor: w = 360 * k / 60/2 * π (rad / sec) ( k = 1
0, 30, 100, 300).

Then, each of the above parameters is calculated by the above equation (1).
2, the position of the measurement point after t seconds (r
(t), θ (t)) can be obtained.

Therefore, by sequentially plotting the positions (r (t), θ (t)) of the measurement points for a predetermined time (after t seconds),
When the rotation speed of the rotation susceptor is 10 rpm, the trajectory L1,
In the case of 30 rpm, the locus L2, in the case of 100 rpm, the locus L3, in the case of 300 rpm, the locus L4,
The trajectory of the measurement point on the substrate corresponding to each rotation speed of the rotation susceptor can be accurately analyzed.

FIG. 6 shows the first to fourth rotations when the rotation speed of the rotation susceptor is 10 rpm under the above measurement conditions.
Regarding the first rotation, the trajectories L11 to L14 obtained by the above-described method are shown.

Accordingly, by associating the temperature data continuously measured by the radiation thermometer 7 with respect to each of the trajectories L11 to L14 of the measurement points for each elapsed time, the temperature distribution over the entire surface of the substrate is estimated by analogy. It is possible to do.

FIG. 7 shows that under the above measurement conditions,
FIG. 13 shows the trajectories L21 to L24 obtained by the above-described method for the first to fourth rotations when the rotation speed of the rotation susceptor is 30 rpm.

Also in this case, each locus L2 of the measurement point
For 1 to L24, the temperature data continuously measured by the radiation thermometer 7 is made to correspond to each elapsed time, so that the temperature distribution over the entire surface of the substrate can be inferred and measured.

Although illustration is omitted, when the rotation speed of the rotation susceptor is set to 100 rpm or 300 rpm, the locus of each rotation can be similarly analyzed to measure the temperature distribution on the entire surface of the rotation susceptor. It is possible.

The trajectory of the measurement point as described above is analyzed for a larger number of rotations of the rotation susceptor, and the temperature data is obtained for a large number of trajectories of the measurement point passing substantially uniformly on each part on the surface of the substrate. By coping with each elapsed time, measurement accuracy of the temperature distribution of the substrate can be further improved.

The data on the locus of the measurement points obtained as described above and the measurement results of the temperature distribution of the substrate are stored in a storage device such as a hard disk or a display such as a CRT under the control of a control device or the like. Output to
Alternatively, printout may be performed by a printer.

Then, based on the temperature distribution of the substrate measured in this way, it is also possible to grasp the temperature distribution in the reaction furnace and the like, and to analyze the temperature-related analysis results for controlling the crystal growth temperature of the reaction furnace. By feeding back such information, it can be expected that a higher quality crystal having a uniform film thickness distribution, specific resistance value distribution and the like can be obtained by vapor phase growth.

The above embodiment is merely one specific example of an apparatus to which the method according to the present invention is applied, and the present invention is of course not limited by the present invention.

That is, the diameters, rotation speeds, and the like of the revolution susceptor and the rotation susceptor are not limited to those described in this embodiment, and can be set arbitrarily.

Further, the number and the arrangement pattern of the substrates mounted on the susceptor are not limited to the arrangement of four substrates at every 90 degrees as in the above embodiment, but an arbitrary number of substrates are arranged in a predetermined pattern. May be performed.

In this embodiment, an example in which a compound semiconductor single crystal thin film is grown on a compound semiconductor substrate has been described. However, the present invention is not limited to these.
The present invention is also applicable to a case where a semiconductor other than a compound semiconductor, or a thin film of an oxide or a metal other than a semiconductor is grown on a Si substrate, a glass substrate, a ceramic substrate, or the like.

Although the MOCVD method has been taken as an example of the vapor phase growth method, the present invention is not limited to this, and the vapor phase growth method such as chloride CVD, halide CVD, vapor deposition, and molecular beam epitaxy (MBE) can be used. Applicable.

The position detecting means is not limited to the light transmitting type as described above, and other types can be applied, but a non-contact type is preferable.

[0062]

According to the present invention, there is provided a method for measuring a temperature distribution of a substrate mounted on a rotary susceptor provided in a reactor for vapor-phase growth of a thin film, wherein the method is provided at a predetermined position. The temperature measuring means continuously measures the surface temperature of the substrate mounted on the rotating susceptor, and, based on information on the number of rotations of the susceptor, determines the locus of the measurement point of the substrate changing with the rotation of the susceptor. Analyze, and based on the analysis result, the temperature distribution measured on the substrate surface is calculated by associating the temperature data measured by the temperature measuring means with each measurement point. Being able to measure temperature distribution and properly controlling the crystal growth temperature to contribute to the vapor phase growth of higher quality crystals with uniform thickness distribution, resistivity distribution, etc. But There is an effect that kill.

[Brief description of the drawings]

FIG. 1 is a graph showing a measurement result by a conventional temperature measurement method.

FIG. 2 shows a method of measuring the temperature distribution of a substrate according to the present invention using MOC.
FIG. 3 is a schematic explanatory diagram when applied to epitaxial growth by a VD method.

FIG. 3 is a top view showing a schematic configuration of a rotary susceptor.

FIG. 4 is an explanatory diagram showing a positional relationship between a revolution susceptor and a rotation susceptor.

FIG. 5 is an explanatory diagram showing a relationship between a trajectory of a measurement point on a rotation susceptor and a rotation speed.

FIG. 6 is a diagram showing a locus of a measurement point on the rotation susceptor (10 rpm).

FIG. 7 is a diagram showing a locus of a measurement point on the rotation susceptor (30 rpm).

[Explanation of symbols]

L1 to L4, L11 to L14, L21 to L24 Trajectories of measurement points on the substrate a, b, c, d Substrate 1 Rotary susceptor 1A Revolving susceptor 1B Rotating susceptor 2 Fixed gear for rotation introduction 3 Disk for position detection 4 Position detection Hole 5 Light emitting element 6 Light receiving element 7 Thermal radiation thermometer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-37022 (JP, A) JP-A-5-259082 (JP, A) JP-A-9-162128 (JP, A) JP-A-6-162128 314656 (JP, A) Japanese Utility Model 3-50056 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C30B 25/16 G01J 5/10 H01L 21/205

Claims (4)

(57) [Claims] An internal gear is provided along the circumference to contact a drive source.
A disk-shaped revolving susceptor that is rotatable
The external gear that engages with the internal gear of the revolution susceptor is
Along, is formed in a disk shape on which a substrate can be placed,
It is made to rotate along the internal gear of the revolution susceptor.
A method for measuring the temperature distribution of a substrate mounted on a rotary susceptor provided in a reactor for vapor-phase growing a thin film comprising a predetermined number of rotation susceptors , wherein the substrate on each rotation susceptor is provided. Facing a predetermined position where
The temperature measuring means provided in the surface temperature of the substrate to be placed on a susceptor for rotationally measured continuously, based on information about the rotational speed of the susceptor, the substrate to be displaced with the rotation of the susceptor Analyzing the trajectory of the measuring point, and calculating the temperature distribution on the substrate surface by associating the temperature data measured by the temperature measuring means with each measuring point based on the analysis result; Temperature distribution measurement method. 2. The analysis of the locus of the measurement points on the substrate includes: a distance from the center of the revolution susceptor to the center of the rotation susceptor; R, a radius of the rotation susceptor, r, an angular velocity of the revolution susceptor, and an angular velocity of the rotation susceptor. w, and when the measurement point is represented on the r-θ coordinate with the center of the rotation susceptor taken as the origin, the starting point is defined as the time when the center of the substrate on the rotation susceptor coincides with the position of the temperature measuring means ( Assuming that the position of (r (t), θ (t)) is measured after t seconds as (0 second), the position is calculated by the following equation (1). 2. The method of measuring a temperature distribution of a substrate according to claim 1, wherein the method is performed by calculating the following equation: θ 1 (t) = (w−W / 2) t (2) Wherein the temperature measuring means, the temperature distribution measuring method of a substrate according to claim 1 or claim 2, characterized in that provided opposite the position where the center of the substrate on the rotation susceptor passes . 4. A temperature distribution calculated based on the temperature distribution measuring method for a substrate according to claim 1,
A method for growing a thin film, comprising: growing a thin film on the substrate by controlling the temperature in the reaction furnace so that the temperature of the substrate on the rotation susceptor becomes uniform.