JP2010100914A - Method for measuring temperature of substrate of vapor growth device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring the temperature of a substrate of a vapor growth device capable of reliably measuring the temperature of the substrate by a simple apparatus constitution and simple signal processing. <P>SOLUTION: There is provided a trigger for detecting that a susceptor makes one turn, and there is provided a thermometer to continuously measure the temperature of the susceptor and the substrate. The temperature of the substrate is defined by selecting the temperature of measurement of measuring the temperature of a substrate part based on the turning state of the susceptor detected by the trigger, the set value preset according to the relationship among the susceptor, the substrate and the trigger, and the temperature of measurement of the thermometer. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for measuring a substrate temperature of a vapor phase growth apparatus, and more particularly to a method for measuring the temperature of a substrate when a thin film is vapor grown using a self-revolving vapor phase growth apparatus.

A plurality of substrates are held at equal intervals in the circumferential direction on a disc-shaped susceptor rotatably provided in the film forming chamber, and the substrate is rotated through the susceptor by heating means while giving revolving motion and rotation motion to the substrate. A self-revolution type vapor phase growth apparatus is known in which a raw material gas is supplied radially from the center of the film formation chamber to the outside to vapor phase grow a thin film (for example, Patent Document 1). reference.). Further, in a vapor phase growth apparatus of a type in which a susceptor holding a substrate rotates, the temperature at a specific position of the substrate is measured when the susceptor rotates to a specific position in order to measure the substrate temperature during the vapor phase growth. A method has been proposed (see, for example, Patent Document 2).
JP 2007-243060 A Japanese Patent Laid-Open No. 11-79887

  However, the temperature measurement method described in Patent Document 2 has a problem in terms of cost because the device configuration becomes complicated and signal processing becomes complicated.

  Accordingly, an object of the present invention is to provide a substrate temperature measuring method for a vapor phase growth apparatus that can reliably measure the temperature of a substrate with a simple equipment configuration and simple signal processing.

  In order to achieve the above object, the substrate temperature measuring method of the vapor phase growth apparatus of the present invention holds a plurality of substrates at equal intervals in the circumferential direction of a rotating susceptor, and supplies a source gas while heating the substrates by a heating means. In the method for measuring the temperature of the substrate in a vapor phase growth apparatus for supplying and vapor-depositing a thin film on the substrate surface, a trigger for detecting that the susceptor has made one revolution is provided, and the susceptor and the substrate A thermometer for continuously measuring the temperature of the susceptor, the rotation state of the susceptor detected by the trigger, a preset value set according to the relationship between the susceptor, the substrate and the trigger, and the measurement of the thermometer Based on the temperature, the measurement temperature obtained by measuring the temperature of the substrate portion is selected.

  Furthermore, in the substrate temperature measuring method of the present invention, the trigger is provided at a position corresponding to the center between any two adjacent substrates of the plurality of substrates, and the set value is determined by the susceptor. In a state where the rotation speed is X [rpm] and the susceptor is rotating at the X [rpm], the temperature measurement of the first substrate positioned immediately after the trigger is detected and immediately after the trigger is rotated in the susceptor rotation direction. The time A [sec] required for the temperature measurement point of the thermometer to reach the start point and the temperature measurement point of the thermometer from the temperature measurement start point of the first substrate to the temperature measurement end point The temperature of the thermometer is between the time B [sec] required and the temperature measurement start point of the second substrate located immediately after the first substrate temperature measurement end point in the susceptor rotation direction of the first substrate. Time C [s required to reach the measurement point It is characterized in that it is a c].

In addition, the selection of the measurement temperature includes the actual rotation speed Y [rpm] of the susceptor measured by detecting the trigger, the number of substrates [n] (n is a natural number of 2 or more) held on the susceptor, Based on the set values of the rotational speed X [rpm], the time A [sec], the time B [sec], and the time C [sec], the following equations (1) and (2):
S (m) = ((B + C) × (m−1) + A) / (Y / X) (1)
T (m) = ((B + C) × (m−1) + A + B) / (Y / X) (2)
The time S (m) [sec] from when the trigger is detected until the temperature measurement start point of the thermometer reaches the temperature measurement start point on the m-th substrate (m is a natural number of 1 to n) and the trigger are detected. After that, a time T (m) [sec] until the temperature measurement point of the thermometer reaches the temperature measurement end point on the m-th substrate is calculated, and the time T (m) is calculated from the time S (m) [sec]. ) The temperature measured up to [sec] is the temperature of the m-th substrate.

  According to the substrate temperature measuring method of the vapor phase growth apparatus of the present invention, basically, the set value determined by the diameter of the susceptor, the diameter of the substrate and the number of substrates held by the susceptor, and the rotation state of the susceptor detected by the trigger Thus, it is possible to sort out the part of the substrate that is the temperature measurement target and the part of the other susceptor, etc. Therefore, in addition to the thermometer, it is only necessary to provide a trigger for detecting the rotation state of the susceptor. It can be simplified. In addition, since the thermometer only needs to perform a calculation process for continuously measuring the temperature and extracting only the temperature of the portion of the substrate that is a temperature measurement target, the signal processing can be simplified.

  FIG. 1 is an explanatory diagram showing a temperature measurement state in the substrate temperature measurement method of the present invention, FIG. 2 is a diagram showing changes in the measured temperature, and FIG. 3 is a diagram of a vapor phase growth apparatus capable of implementing the substrate temperature measurement method of the present invention. It is a section front view showing an example.

  First, in the vapor phase growth apparatus shown in FIG. 3, a disk-shaped susceptor 12 is rotatably provided in the film forming chamber 11, and a substrate holding member 13 having an external gear on the outer periphery of the susceptor 12 is provided in the circumferential direction. A self-revolving vapor phase growth apparatus provided so as to be rotatable at intervals and having an internal gear member 14 fixed so as to surround the outer periphery of the susceptor 12. The susceptor 12 rotates through the center of the bottom surface of the film forming chamber 11. A heater 16 as a substrate heating means is provided below the susceptor 12 and supported by a shaft 15. A radiation thermometer 17 for measuring the substrate temperature is inserted therein. In addition, a gas introduction part 18 for introducing a source gas is provided in the central part on the surface side of the susceptor 12 in the film formation chamber 11, and a gas discharge part 19 is provided in the outer peripheral part of the film formation chamber 11. The substrate holding member 13 constitutes a part of the susceptor 12, and these are usually made of carbon.

  When a thin film is formed on a substrate using this vapor phase growth apparatus, the film introduction chamber 18 is heated from the gas introduction unit 18 while the substrate is heated to a predetermined temperature by the heater 16 via the susceptor 12 and the substrate holding member 13. A raw material gas is introduced into 11, and exhaust gas is discharged from the film forming chamber 11 through the gas discharge unit 19. At this time, when the susceptor 12 is rotationally driven by the rotating shaft 15, the substrate holding member 13 revolves around the rotating shaft 15, and the external gear of the substrate holding member 13 meshes with the internal gear member 14, and the substrate holding member When 13 rotates, the substrate held by the substrate holding member 13 rotates and revolves.

  Next, an example of a method for measuring the temperature of the substrate using such a self-revolving vapor phase growth apparatus will be described with reference to FIGS. First, as shown in FIG. 1, the susceptor 12 (including the substrate holding member 13; the same applies hereinafter) holds eight sapphire substrates P at equal intervals in the circumferential direction. Rotate (revolve) in the same direction at the same rotational speed as the susceptor 12.

  The susceptor 12 or the rotating shaft 15 that rotates together with the susceptor 12 is provided with a trigger for detecting that the susceptor 12 has made one rotation. As the trigger, any detection means can be used as long as it can detect that the susceptor 12 has made one rotation, and various sensors such as mechanical and electrical can be used. A circle A shown in FIG. 1 indicates a locus through which the temperature measurement point of the radiation thermometer 17 passes, and is set so as to pass through the central portion of the substrate P or in the vicinity thereof.

  FIG. 2 shows a change in temperature measured by the radiation thermometer 17, and the temperature at each temperature measurement point when the temperature measurement point moves from the trigger position L0 according to the rotation of the susceptor 12 is shown. Represents. As can be seen from FIG. 2, there is a difference between the measurement temperature of the portion where the substrate P exists on the upper surface and the measurement temperature of the portion where the substrate P does not exist on the upper surface, for example, a portion where the substrate P exists. When the measurement temperature is 800 ° C., the measurement temperature of the portion where the substrate is not present is about 770 ° C., and a difference of about 30 ° C. occurs.

  That is, in the range of the rotation distance from the trigger position L0 to the trigger-side outer edge point L1 of the first substrate P1, the measurement temperature is low because the substrate does not exist on the upper surface, and the substrate P1. In the range of the rotation distance from the trigger-side outer edge point L1 to the counter-trigger-side outer edge point L4 of the substrate P1, the substrate P1 is present, so the measurement temperature is high. Further, the temperature is low from the point L4 on the counter trigger side outer edge of the substrate P1 to the point L5 on the trigger side outer edge of the substrate P2, and from the point L5 on the trigger side outer edge of the substrate P2 to the point L8 on the counter trigger side outer edge of the substrate P2. The temperature is high. Similarly, the temperature below the substrate P3 is high at the portion where the substrate P is present, and the temperature is low at the portion where the substrate P is not present.

  Therefore, it is necessary to select the measurement temperature of the portion where the substrate P exists from the measurement temperature of the portion where the substrate P exists and the measurement temperature of the portion where the substrate P does not exist, and use this as the substrate temperature. . Before starting the sorting operation, a control means such as a computer for performing arithmetic processing necessary for the sorting operation is basically used as a diameter of the susceptor 12 (either diameter or radius is acceptable) or a substrate holding member provided on the susceptor 12. A set value determined in advance by the diameter of the trajectory through which the 13 central points pass, the diameter of the substrate, and the number of substrates held by the susceptor is input in advance. From these set values and the rotation state of the susceptor 12 detected by the trigger, it is possible to select a portion where the substrate P is present and a portion where the substrate P is not present.

  For example, a numerical value that is easy to calculate will be described. Four substrates P having a diameter of about 60 mm are held at equal intervals on the outer periphery of the susceptor 12 having a diameter of about 200 mm, and a circle of a trajectory that passes through the center of the substrate P. When the circumference is about 360 mm, when the susceptor 12 makes one turn, the length of the portion where the substrate P is present is about 60 mm × 4 and about 240 mm, and the length of the portion where the substrate P is not present is about 360 mm. -About 240 mm, about 120 mm, and about 120 mm / 4 between adjacent substrates, each about 30 mm.

  Therefore, in this case, due to the rotation of the susceptor 12, at the temperature measurement point of the radiation thermometer 17, a portion of about 60 mm in the range where the substrate exists and a portion of about 30 mm in the range where the substrate does not exist alternately. Will pass through. At this time, if the susceptor 12 is rotating at one revolution per minute (1 rpm), about 60 seconds when the susceptor 12 makes one revolution, about 10 seconds for the portion with the substrate and about 5 seconds for the portion without the substrate. It will occur four times alternately. If the trigger position L0 is set at the outer edge of the rotation direction of the substrate, the substrate is present for about 10 seconds from the trigger position L0, the substrate is absent for about 5 seconds, and the portion with the substrate for about 10 seconds is referred to below. The portion without the substrate for about 5 seconds is repeated. Thereby, the measurement temperature of the part in which the board | substrate P exists can be selected and taken out from each temperature measurement point.

  In FIG. 1, eight substrates P are held on the susceptor 12, and the trigger is provided at a position L0 corresponding to the center between any two adjacent substrates P1 and P8 among the plurality of substrates. . Further, as the set values, when the susceptor 12 is rotated at the rotational speed X [rpm] and the susceptor 12 is rotating at the X [rpm], the position is set immediately after the trigger is detected and immediately after the trigger is rotated. The time A [sec] required to reach the temperature measurement start point L2 of the first substrate P1 and the time required to reach the temperature measurement end point L3 from the temperature measurement start point L2 of the first substrate P1 B [sec] and from the temperature measurement end point L3 of the first substrate P1 to the temperature measurement start point L5 of the second substrate P2 positioned immediately after the susceptor rotation direction of the first substrate P1. Time C [sec] required for.

  As described above, each of the set values A, B, and C includes the diameter of the susceptor 12 or the diameter of the locus through which the central point of the substrate holding member 13 provided on the susceptor 12 passes, the diameter of the substrate, and the number of substrates held by the susceptor. If it is determined, it can be easily obtained by calculation. The rotational speed X is arbitrary, and the actual rotational speed of the susceptor 12 set during processing may be set as a set value, and “1” is simply set as the set value. You can also. The reason why the outer edge portion of the substrate P is not set as the temperature measurement start point or the temperature measurement end point is that the deviation between the designed substrate position and the actual substrate position is taken into consideration. The distance to the start point and the temperature measurement end point can be arbitrarily set according to conditions such as the diameter of the substrate.

  Here, the actual rotation speed Y [rpm] of the susceptor 12 measured by detecting the trigger, the number of substrates P held by the susceptor 12 [n] (n is a natural number of 2 or more), and the set value Based on the rotation speed (set rotation speed) X [rpm], time A [sec], time B [sec], and time C [sec], m (m is 1 to n) after the trigger is detected A procedure for measuring the temperature of the (natural number) th substrate will be described.

  First, the time S (1) [sec] from when the trigger is detected until the temperature measurement start point L2 of the first substrate P1 reaches the temperature measurement start point L2 is the time A [sec]. The actual rotational speed may be corrected with respect to the set rotational speed, and can be obtained by S (1) = A / (Y / X). If the set rotational speed X = actual rotational speed Y, S (1) = A. The time T (1) [sec] from the detection of the trigger to the temperature measurement end point L3 on the substrate P1 is the number of rotations with respect to the sum of the time A [sec] and the time B [sec]. Therefore, T (1) = (A + B) / (Y / X) is obtained.

  The time S (2) [sec] until the temperature measurement point reaches the temperature measurement start point L6 on the second substrate P2 is the sum of the time A [sec], the time B [sec], and the time C [sec]. If the rotation number is corrected to the sum of the time S (2) [sec] and the time B [sec], the temperature measurement is completed at the temperature measurement end point L7 on the substrate P2. Time T (2) [sec] until the point is reached is obtained.

  That is, the time S (m) until the temperature measurement point reaches the temperature measurement start point in the m-th substrate is the time A [sec] until the temperature measurement point reaches the temperature measurement start point of the first substrate P1. ] And the sum of the time B [sec] and the time C [sec] that the temperature measurement point has passed before reaching the m-th sheet, and the rotation number may be corrected. The time T (m) until the temperature measurement point reaches the temperature measurement end point is the sum of the time S (m) and the time B [sec] until the temperature measurement point reaches the temperature measurement start point. Therefore, the time S (m) until the temperature measurement point reaches the temperature measurement start point on the m-th substrate can be expressed by the following equation (1). The time T (m) required for the temperature measurement point to reach the temperature measurement end point on the substrate is expressed by the following equation (2). It can be represented by.

S (m) = ((B + C) × (m−1) + A) / (Y / X) (1)
T (m) = ((B + C) × (m−1) + A + B) / (Y / X) (2)

For example, the number of substrates n = 8, set rotation speed X = 1 rpm, time A = 2.5 sec, time B = 3.5 sec, time C = 4.0 sec, and actual rotation of the susceptor detected by the trigger When the number Y is 5 rpm and the temperature measurement is started with the time when the trigger is detected as 0 sec, the time (measurement start time) S (m) that the temperature measurement point reaches the temperature measurement start point of each substrate and the temperature measurement of each substrate The time taken for the temperature measurement point to reach the end point (measurement end time) T (m) is the time shown in Table 1. When the temperature measurement point passes through the eighth substrate P8 and a trigger is detected, the measurement time is reset and returns to zero.

By setting the temperature measured by the radiation thermometer 17 in the range between each measurement start time and each measurement end time calculated in this manner as the substrate temperature, unnecessary measurement temperatures are eliminated and each substrate is measured. The temperature can be measured accurately. Table 2 shows the temperature of each substrate measured as described above.

  The temperature of each substrate is an average value of the temperatures measured in the temperature measurement range from the temperature measurement start point to the temperature measurement end point of the substrate, and the number of temperature measurement points in the temperature measurement range on each substrate is the susceptor 12. For example, when the rotation speed is 1 rpm and the calculation processing speed is 50 msec, the time B in the temperature measurement range is 3500 msec, so the temperature measurement point is 70 points. Become. Further, by further dividing the 70 temperature measurement points, it is possible to measure the temperature of the outer peripheral portion and the temperature of the central portion of each substrate.

  Furthermore, the substrate temperature obtained in this way is transmitted as a temperature signal to a heater control means for controlling the output of the heater 16, and output control according to the measured temperature is performed. The temperature signal transmitted to the heater control means may be a temperature obtained by averaging measured temperatures for one rotation of the susceptor 12 or may be temperature information including a maximum temperature, a minimum temperature, and temperature variations.

  The substrate temperature measuring method of the present invention is not limited to the self-revolving type shown in the present embodiment, but can be applied to a vapor phase growth apparatus that performs only revolving, and a method of vapor phase growth in which the substrate is held downward. It can also be applied to devices. The trigger can be installed at any position as long as the rotation state of the susceptor can be detected, and the trigger signal may be obtained not only from the susceptor and the rotation shaft but also from a motor that drives the rotation shaft. The method for detecting the rotation state is also arbitrary. Further, any temperature measuring means can be used for the thermometer, and the installation position is also arbitrary. For example, the thermometer can be provided on the susceptor upper surface side (the top plate side of the film forming chamber 11) in this embodiment. Furthermore, any heating means can be used as the heating means, and it is possible to use a means for heating the substrate from the substrate surface side.

It is explanatory drawing which shows the temperature measurement state in the substrate temperature measuring method of this invention. It is a figure which shows the change of the measured temperature. It is a cross-sectional front view which shows one example of the vapor phase growth apparatus which can implement the substrate temperature measuring method of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Film-forming chamber, 12 ... Susceptor, 13 ... Substrate holding member, 14 ... Internal gear member, 15 ... Rotating shaft, 16 ... Heater, 17 ... Radiation thermometer, 18 ... Gas introduction part, 19 ... Gas discharge part

Claims (4)

  A plurality of substrates are held at equal intervals in the circumferential direction of the rotating susceptor, a source gas is supplied while the substrates are heated by a heating means, and a thin film on the substrate surface is grown in a vapor phase. In the method for measuring temperature, a trigger for detecting one rotation of the susceptor is provided, and a thermometer for continuously measuring the temperature of the susceptor and the substrate is provided, and the susceptor detected by the trigger is provided. The measurement temperature obtained by measuring the temperature of the substrate portion is selected on the basis of the set value preset according to the rotation state of the susceptor, the substrate and the trigger, and the measured temperature of the thermometer. A method for measuring a substrate temperature of a vapor phase growth apparatus.   2. The substrate temperature measuring method for a vapor phase growth apparatus according to claim 1, wherein the trigger is provided at a position corresponding to the center between any two adjacent substrates of the plurality of substrates.   The set value is 1 [X] [rpm], which is the rotation speed of the susceptor, and 1 immediately after the trigger is detected in the state where the susceptor is rotating at [X] [rpm]. The time A [sec] required for the temperature measurement point of the thermometer to reach the temperature measurement start point of the first substrate and the temperature measurement start point of the first substrate from the temperature measurement start point of the first substrate The time B [sec] required for the temperature measurement point to reach and the temperature measurement start of the second substrate located immediately after the temperature measurement end point of the first substrate immediately after the susceptor rotation direction of the first substrate is started. 3. The method for measuring a substrate temperature of a vapor phase growth apparatus according to claim 2, wherein a time C [sec] required until the temperature measurement point of the thermometer reaches the point. The selection of the measurement temperature includes the actual rotation speed Y [rpm] of the susceptor measured by detecting the trigger, the number of substrates [n] (n is a natural number of 2 or more) held on the susceptor, and the setting. Based on the values of the rotational speed X [rpm], time A [sec], time B [sec], and time C [sec], the trigger is detected by the following equations (1) and (2). To m (m is a natural number between 1 and n) sheets, the time S (m) [sec] until the temperature measurement start point of the thermometer reaches the temperature measurement start point and the m sheets after the trigger is detected The time T (m) [sec] until the temperature measurement point of the thermometer reaches the temperature measurement end point on the eye substrate is calculated, and from time S (m) [sec] to time T (m) [sec]. The temperature measured during this period is the temperature of the mth substrate. Substrate temperature measuring method of the vapor phase growth apparatus according to claim 3,.
S (m) = ((B + C) × (m−1) + A) / (Y / X) (1)
T (m) = ((B + C) × (m−1) + A + B) / (Y / X) (2)

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