JP6172672B2 - Method for measuring film thickness of vapor phase growth apparatus - Google Patents

Description

  The present invention relates to a method for measuring a film thickness of a vapor phase growth apparatus, and relates to a film thickness of a vapor phase growth apparatus capable of measuring the thickness of a film grown by a vapor phase growth method using a self-revolving vapor phase growth apparatus. It relates to a measurement method.

Conventionally, a plurality of substrates are placed at equal intervals in the circumferential direction on a revolving disc-shaped susceptor in the chamber, and the plurality of substrates are heated while rotating the plurality of substrates, and a source gas is introduced into the chamber. A self-revolving vapor phase growth apparatus is known in which a thin film (for example, a film having a thickness of 10 μm or less) is vapor-grown by supplying
In such a self-revolution type vapor phase growth apparatus, from the viewpoint of improving the in-plane uniformity of the thin film formed on the substrate, the rotation speed of the susceptor during revolution may be changed according to the growth rate of the thin film. .

  In Patent Document 1, a trigger for detecting that the susceptor has made one rotation is provided, and a thermometer for continuously measuring the temperature of the susceptor and the substrate is provided. The rotation state of the susceptor detected by the trigger, and the susceptor Measurement of the temperature of the portion of the susceptor on which the substrate is placed based on the set value preset according to the relationship between the substrate and the trigger and the measurement temperature of the susceptor measured by the thermometer A substrate temperature measuring method for a vapor phase growth apparatus for selecting a temperature is disclosed.

  By using the substrate temperature measuring method of the vapor phase growth apparatus disclosed in Patent Document 1, it becomes possible to grasp the temperatures of a plurality of substrates. This makes it possible to form a thin film having a good film quality on a plurality of substrates.

In addition, when forming a thin film using a vapor phase growth apparatus, it is also important to grasp the thickness of the thin film during growth and form a thin film having a predetermined thickness.
However, Patent Document 1 does not disclose any method for measuring the thickness of a thin film grown on the surfaces of a plurality of substrates.

Patent Document 2 discloses a measuring instrument capable of measuring the thickness and refractive index of a semiconductor crystal thin film formed on a substrate.
The measuring device irradiates the thin film formed on the surface of the substrate with laser light having a predetermined wavelength, and obtains the thickness of the thin film based on the amplitude of the reflected intensity of the reflected laser light. It is a measuring instrument that can be used.

JP 2010-100194 A US Pat. No. 8,233,158

  However, when measuring the thickness of a thin film (thin film formed by a self-revolving vapor deposition apparatus) formed at the center of a plurality of substrates using the measuring instrument disclosed in Patent Document 2, the film thickness The measurement cycle depends on the revolution cycle of the susceptor.

Specifically, when a plurality of substrates are placed on the susceptor in the circumferential direction of the susceptor and the thickness of a thin film grown at the center of one of the substrates is measured, the susceptor rotates once. The film thickness is only measured once.
For this reason, if the revolution cycle of the susceptor is slow (in other words, the susceptor rotation speed is slow), the film thickness measurement interval becomes very long.

FIG. 8 is a plan view of the main part of the vapor phase growth apparatus used when acquiring the data shown in FIG.
FIG. 9 is a diagram for explaining the relationship between the difference in the growth rate of the thin film formed using the vapor phase growth apparatus shown in FIG. 8 and the amplitude of the reflection intensity of the laser light reflected on the surface of the substrate. It is.

  Here, as a prior study, the present inventor uses a vapor deposition apparatus 300 for processing six wafers shown in FIG. 8 and the rotation speed of the susceptor 301 during revolution is 5 rpm (in other words, formed on one substrate 302). And an AlN (aluminum nitride) film (thin film 303) having a thickness of 300 nm is grown under the condition that the measurement period of the thin film 303 is 12 sec) and the growth rate of the thin film 303 is 1 μm / hour (slow growth rate), Using the film thickness measuring instrument disclosed in Patent Document 2 (specifically, EpiCurve TT Two AR, a film thickness measuring instrument manufactured by Raytec), the growing thin film 303 positioned at the center 302A of the substrate 302 is used. Laser light was irradiated, and the relationship between the reflection intensity of the laser light reflected from the substrate 302 and time was determined.

  Specifically, the growth rate of the thin film 303 is 1 μm / hour, 5 μm / hour, 10 μm / hour (high growth rate), and the relationship between the reflection intensity of the laser light reflected from the substrate 302 and time is shown. Asked. The result is shown in FIG.

As shown in FIG. 9, when the growth rate of the thin film 303 is high, it is difficult to correctly measure the amplitude of the reflection intensity from the reflection intensity of the laser beam. Therefore, the thickness of the thin film is obtained based on the reflection intensity. I can't.
That is, there is a problem that the thickness of the thin film 303 during the growth cannot be measured when the growth rate of the thin film 303 is high by simply combining Patent Documents 1 and 2.

  Therefore, the present invention measures the thickness of a film in the middle of growth without depending on the growth rate of the film formed by the vapor deposition method and the rotation speed of the susceptor (in other words, the number of rotations per unit time). It is an object of the present invention to provide a film thickness measuring method for a vapor phase growth apparatus that can be used.

In order to solve the above-mentioned problem, according to the invention according to claim 1, the step of placing a plurality of substrates at equal intervals in the circumferential direction of the susceptor and rotating the susceptor in a state where the plurality of substrates are heated; By supplying a source gas into the chamber in which the susceptor is housed, a film is grown on the surfaces of the plurality of substrates by a vapor phase growth method, and the films grown on the surfaces of the plurality of substrates are And continuously irradiating the laser beam having a predetermined wavelength in an arc shape, and continuously acquiring the thickness of the growing film on the basis of the amplitude of the reflected intensity of the reflected laser beam. An area on the substrate that is irradiated with the laser light, and a rotation speed of the susceptor when a trigger signal is transmitted, and a preset number of the susceptor, the substrate, and the trigger signal. Settings obtained from relationships Value, determined based on the respective data of the reflected intensity reflected from said plurality of substrates is treated as data of the reflected intensity reflected from one of the substrate, the film grown on the surface of the plurality of substrates A method for measuring a film thickness of a vapor phase growth apparatus is provided, in which the period for measuring the thickness of the vapor phase growth apparatus is made shorter than the case where the reflection intensity measured with only the same substrate is treated as one data .

  According to the invention of claim 2, in the step of continuously acquiring the thickness of the film, the susceptor among the surfaces of the plurality of substrates is used as a region on the substrate to be irradiated with the laser light. 2. The method of measuring a film thickness of a vapor phase growth apparatus according to claim 1, wherein a region through which a circumference of a circle having a center coincident with the center of is passed.

  According to a third aspect of the present invention, the set value includes a rotation speed X of the susceptor and a position where the trigger signal of the susceptor is detected in a state where the susceptor rotates at the rotation speed X. The time E required for the film thickness measuring point of the film thickness measuring device to reach the film thickness measuring start point of the first substrate positioned immediately after the rotation direction of the susceptor, and the film of the first substrate The time F required for the film thickness measuring point to reach the film thickness measuring end point from the thickness measuring starting point to the film thickness measuring end point, and the first substrate from the film thickness measuring end point of the first substrate The time G required until the film thickness measurement point of the film thickness measuring device reaches the film thickness measurement start point of the second substrate positioned immediately after the rotation direction of the susceptor. Item 3. A method for measuring a film thickness of a vapor phase growth apparatus according to Item 1 or 2 is provided.

  Further, according to the invention according to claim 4, the film growth rate of the film is 10 μm / hour or more, wherein the film thickness of the vapor phase growth apparatus according to any one of claims 1 to 3 is characterized. A measurement method is provided.

  The invention according to claim 5 is characterized in that, during the growth of the film, the plurality of substrates placed on the susceptor are rotated. The method for measuring a film thickness of the vapor phase growth apparatus according to the item is provided.

  According to the film thickness measuring method of the vapor phase growth apparatus of the present invention, by supplying the source gas into the chamber in which the susceptor is accommodated, the film is grown on the surface of the plurality of substrates by the vapor phase growth method. A laser beam having a predetermined wavelength is continuously irradiated in a circular arc shape on a film that grows on the surface of a plurality of substrates, and based on the amplitude of the reflected intensity of the reflected laser beam, Including a step of continuously acquiring the thickness, and a region on the substrate to be irradiated with the laser light is set to the number of rotations of the susceptor when the trigger signal is transmitted, and the susceptor, the substrate, and the trigger signal are preset. It is possible to shorten the cycle of film thickness measurement by treating the reflection intensity of laser light reflected from a plurality of substrates as one data by determining based on the setting value obtained from the relationship Become.

  As a result, even when the rotation speed of the susceptor is slow and / or the growth speed of the film grown on the substrate is fast, the reflected intensity of the reflected laser light can be measured correctly, so that it can be obtained. Based on the amplitude of the reflected intensity, the film thickness during the growth can be obtained.

It is sectional drawing which shows typically schematic structure of the vapor phase growth apparatus used when performing the film thickness measuring method of the vapor phase growth apparatus which concerns on embodiment of this invention. It is sectional drawing to which the part enclosed by the area | region A among the vapor phase growth apparatuses shown in FIG. 1 was expanded. It is a top view for demonstrating the area | region (section) where the measurement part of a film thickness measuring device irradiates a laser beam with respect to a board | substrate, when six board | substrates are mounted on a susceptor. It is a top view for demonstrating the temperature measurement of the board | substrate by a thermometer. It shows the change in the reflection intensity of the laser beam measured by the film thickness measuring instrument, and each time when the measurement point at which the reflection intensity is measured moves from the point L ₀ where the measurement point is generated according to the rotation of the susceptor. It is a schematic diagram for demonstrating the reflection intensity in a measurement point. It shows the surface temperature and the change of the surface temperature of the susceptor of the substrate, schematic for explaining the surface temperature and the surface temperature of the susceptor of the substrate at each measurement point when the measurement point is moved from the point L ₀ to generate a trigger It is a typical figure. The relationship between the reflection intensity (au) of the laser beam acquired by the Example and the comparative example and elapsed time (sec) is shown. It is a top view of the principal part of the vapor phase growth apparatus used when acquiring the data shown in FIG. It is a figure for demonstrating the relationship between the difference in the growth rate of the thin film formed using the vapor phase growth apparatus shown in FIG. 8, and the amplitude of the reflection intensity of the laser beam reflected by the surface of a board | substrate.

  Embodiments to which the present invention is applied will be described below in detail with reference to the drawings. Note that the drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the size, thickness, dimensions, etc. of the respective parts shown in the figure are the dimensional relationships of the actual vapor phase growth apparatus. May be different.

(Embodiment)
FIG. 1 is a cross-sectional view schematically showing a schematic configuration of a vapor phase growth apparatus used when performing a film thickness measuring method for a vapor phase growth apparatus according to an embodiment of the present invention.

  Referring to FIG. 1, a vapor phase growth apparatus 10 includes a chamber 11, a susceptor 12, a rotating shaft 13, a detector (not shown), a ring-shaped fixing member 14 with an internal gear, a motor 15, The gas supply unit 17, the source gas supply source 19, the guide member 23, the heating unit 27, the exhaust unit 34, the thermometer 36, the film thickness measuring device 38, and the control device 41 are included.

The chamber 11 includes a chamber main body 11-1, an opening 11-2, a penetrating part 11-3, and a light transmissive window member 11-4.
The chamber body 11-1 has a flat cylindrical shape. The chamber main body 11-1 houses the susceptor 12, the rotating shaft 13, the ring-shaped fixing member 14 with an internal gear, the guide member 23, the heating unit 27, the measuring unit of the thermometer 47, and the like.
The opening 11-2 is provided at the center of the chamber body 11-1. A gas supply unit 17 that guides the source gas into the chamber 11 is inserted into the opening 11-2.

The penetrating part 11-3 is provided so as to penetrate a portion of the chamber body 11-1 that is placed on the susceptor 12 and that faces the center of the substrate 20 that rotates.
The light transmissive window member 11-4 is accommodated in the penetrating part 11-3. The light transmissive window member 11-4 is made of a material that is transparent and capable of transmitting the laser light emitted from the measurement unit 38-1 constituting the film thickness measuring device 38 onto the substrate 20. .
Specifically, as the light transmissive window member 11-4, for example, electrodissolved quartz can be used.

The susceptor 12 includes a susceptor body 12-1, a penetrating portion 12-2, a ring-shaped fixing member 12-3 with an external gear, a plurality of balls 12-4, and a substrate mounting member 12-5.
The susceptor body 12-1 has a disk shape. The upper surface 12-1a of the susceptor body 12-1 is a flat surface. The source gas is supplied radially from the center of the susceptor body 12-1 to the upper surface 12-1a of the susceptor body 12-1 from the source gas supply port 17A in a direction parallel to the upper surface 12-1a (horizontal direction). Is done.

  FIG. 2 is an enlarged cross-sectional view of a portion surrounded by the region A in the vapor phase growth apparatus shown in FIG. 2, the same components as those in the vapor phase growth apparatus 10 shown in FIG.

  Referring to FIGS. 1 and 2, the penetrating portion 12-2 is provided so as to penetrate the outer peripheral portion of the susceptor body 12-1. A plurality of (for example, eight) penetrating portions 12-2 are arranged at predetermined intervals along the outer periphery of the susceptor body 12-1. The centers of the plurality of through portions 12-2 are arranged on the circumference of a circle D (see FIG. 4) centered on the center of the susceptor body 12-1.

The penetrating part 12-2 has a stepped shape in which the opening diameter increases from the lower surface 12-1b to the upper surface 12-1a of the susceptor body 12-1.
In this way, the shape of the penetrating portion 12-2 is a stepped shape having an opening diameter that increases from the lower surface 12-1b of the susceptor body 12-1 to the upper surface 12-1a, thereby providing a plurality of balls 12-4. The ring-shaped fixing member 12-3 with the external gear can be rotatably supported via the.

The ring-shaped fixing member 12-3 with an external gear is disposed in the through portion 12-2 via a plurality of balls 12-4. The upper surface 12-3a of the ring-shaped fixing member 12-3 with the external gear is flush with the upper surface 12-1a of the susceptor body 12-1.
The ring-shaped fixing member 12-3 with the external gear is a ring-shaped member whose upper part is wider than the lower part.

On the outer periphery of the upper part of the ring-shaped fixing member 12-3 with the external gear, an external gear 12-3A having a shape that meshes with the internal gear 14-2 constituting the ring-shaped fixing member 14 with the internal gear is disposed.
Thereby, when the susceptor body 12-1 is rotated by the rotating shaft 13, the ring-shaped fixing member 12-3 with the external gear rotates (rotates) the substrate 20 held on the substrate mounting member 12-5. )

  The ring-shaped fixing member 12-3 with an external gear has an accommodating portion 12-3B that accommodates the substrate mounting member 12-5 at the center thereof. As the accommodating part 12-3B, for example, a disk-shaped space can be used.

  The plurality of balls 12-4 are arranged in a ring shape between the ring-shaped fixing member 12-3 with an external gear and the susceptor body 12-1. The plurality of balls 12-4 support the ring-shaped fixing member 12-3 with an external gear so as to be rotatable with respect to the susceptor body 12-1.

The substrate mounting member 12-5 is disposed in the accommodating portion 12-3B of the ring-shaped fixing member 12-3 with an external gear. The substrate mounting member 12-5 is fixed to a ring-shaped fixing member 12-3 with an external gear.
Thereby, the substrate mounting member 12-5 rotates (spins) together with the ring-shaped fixing member 12-3 with the external gear when the ring-shaped fixing member 12-3 with the external gear is rotated.

The board | substrate mounting member 12-5 is a member made into the disk shape accommodated in the accommodating part 12-3B. The substrate mounting member 12-5 has a substrate accommodating portion 12-5A which is a concave portion capable of accommodating one substrate 20 on the upper surface side thereof.
The upper surface 12-5a of the substrate mounting member 12-5 on which the substrate accommodating portion 12-5A is not formed is flush with the upper surface 12-3a of the ring-shaped fixing member 12-3 with an external gear. The depth of the substrate housing portion 12-5A when the upper surface 12-5a of the substrate mounting member 12-5 is used as a reference is configured to be equal to the thickness value of the substrate 20.

The substrate housing portion 12-5A has a flat substrate placement surface 12-5b that contacts the back surface 20b of the substrate 20. The surface 20a of the substrate 20 accommodated in the substrate accommodating portion 12-5A is configured to be flush with the upper surface 12-5a of the substrate mounting member 12-5.
As a material of the substrate mounting member 12-5 configured as described above, for example, carbon can be used.
As the substrate 20, for example, a silicon (Si) substrate, a silicon carbide (SiC) substrate, a GaN substrate, a sapphire substrate, or the like can be used.

  Referring to FIG. 1, the rotating shaft 13 is disposed below the susceptor 12. The upper end portion of the rotating shaft 13 is connected to the center portion on the lower surface side of the susceptor 12. Thereby, the rotating shaft 13 is supporting the susceptor 12 rotatably. The lower end of the rotating shaft 13 is connected to the motor 15.

A detector (not shown) is provided on the rotating shaft 13. The detector transmits a trigger signal to the film thickness measuring device 38 and the control device 41 when the susceptor 12 rotates once.
Upon receiving the trigger signal, the film thickness measuring device 38 irradiates the surface 20a of the substrate 20 on which the film 21 is grown with laser light, measures the intensity of the reflected laser light (reflected light), and measures the reflected light. Starting to obtain the amplitude of the reflection intensity from the intensity.

1 and 2, the ring-shaped fixing member 14 with an internal gear includes a ring-shaped member 14-1 and an internal gear portion 14-2. The ring-shaped member 14-1 is a ring-shaped member that can accommodate the susceptor 12 inside. The ring-shaped member 14-1 is arranged so as to surround the outer periphery of the susceptor 12.
The internal gear portion 14-2 is provided in a portion of the ring-shaped member 14A that faces the outer periphery of the susceptor 12. The internal gear portion 14-2 has a shape that meshes with the external gear 12-3A.

  Referring to FIG. 1, the motor 15 is connected to the lower end of the rotating shaft 13. The motor 15 measures the actual number of rotations of the susceptor 12 via the rotation shaft 13.

The gas supply unit 17 is inserted into an opening 11-2 provided in the chamber 11. The gas supply unit 17 includes a source gas supply port 17A that supplies a source gas radially with respect to a direction parallel to the upper surface 12-1a of the susceptor body 12-1.
The source gas supply source 19 is connected to the gas supply unit 17 in a state where the source gas can be supplied. For example, when a sapphire substrate is used as the substrate 20 and a gallium nitride (GaN) -based semiconductor layer is formed on the surface of the sapphire substrate, the source gas is trimethylgallium, which is an organic metal compound containing gallium, ammonia, A gas containing can be used.

  The guide member 23 includes a first guide member 23-1 and a second guide member 23-2. The first guide member 23-1 is a space in which the heating unit 27 can be accommodated between the lower surface of the susceptor 12 where the rotation shaft 13 is not provided and the lower surface of the ring-shaped fixing member 14 with gears. It arrange | positions under the susceptor 12 and the ring-shaped fixing member 14 with a gear so that the heating part accommodating part 25 may be formed.

In the first guide member 23-1, a portion located on the outer peripheral edge of the geared ring-shaped fixing member 14 is provided with an inert gas deriving portion 29 for deriving the inert gas from the heating portion accommodating portion 25. It has been.
The 2nd guide part 23-2 is arrange | positioned around the rotating shaft 13 so that the inert gas introducing | transducing part 32 for introducing an inert gas between the surroundings of the rotating shaft 13 may be formed. . The upper end of the second guide portion 23-2 is integrated with the first guide portion 23-1.

The heating unit 27 is accommodated in the heating unit accommodating unit 25 and is disposed below the susceptor 12 and below the ring-shaped fixing member 14 with a gear. The heating unit 27 heats the entire substrate 20 placed on the substrate placement surface 12-5b (see FIG. 2) through the substrate placement member 12-5 so as to have a uniform temperature.
As the heating unit 27, for example, a plurality of heaters can be used. When using a some heater as the heating part 27, it is good to set it as the structure which can control the temperature of each heater independently.

  A sapphire substrate is used as the substrate 20, and a gallium nitride (GaN) semiconductor layer is formed on the surface 20a of the substrate 20 using a source gas containing trimethylgallium, which is an organic metal compound containing gallium, and ammonia. For example, the substrate 20 is heated by the heating unit 27 so that the temperature of the substrate 20 becomes a predetermined temperature within a temperature range of 450 to 1200 ° C.

  The exhaust unit 34 is provided near the inner wall of the chamber 11. The exhaust unit 34 is a gas exhaust path for exhausting unnecessary source gas and the inert gas derived from the inert gas deriving unit 29 to the outside of the chamber 11.

A plurality of thermometers 36 are arranged below the heating unit 27 in a state where the temperature of the susceptor 12 can be measured. The plurality of thermometers 36 are arranged in the radial direction of the chamber 11.
The result relating to the temperature of the susceptor 12 measured by the thermometer 36 is transmitted as temperature data to the control device 41 electrically connected to the heating unit 27. Based on the temperature data, the control device 41 determines that the substrate 20 is The heating unit 27 is controlled to reach a predetermined temperature. As the thermometer 36, for example, a radiation thermometer can be used.

The film thickness measuring instrument 38 includes a measurement unit 38-1 and a calculation unit 38-2 that is electrically connected to the measurement unit 38-1.
The measurement unit 38-1 irradiates a laser having a predetermined wavelength, receives the reflected light of the laser beam, and transmits data regarding the intensity of the reflected light to the calculation unit 38-2. The measurement unit 38-1 is provided above the chamber 11 and at a position facing the light transmissive window member 11-4.

  Thereby, the measurement part 38-1 irradiates a laser beam with respect to the surface 20a of the board | substrate 20 which is mounted on the susceptor 12 and the film | membrane 21 grows through the transparent window member 11-4. In addition, it is possible to receive the reflected light that passes through the film 21 grown on the surface 20a of the substrate 20 and is reflected by the surface 20a of the substrate 20.

  FIG. 3 is a plan view for explaining a region (section) where the measurement unit of the film thickness measuring device irradiates the substrate with laser light when six substrates are placed on the susceptor. 3, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

Referring to FIG. 3, the measurement unit 38-1 continuously irradiates a laser beam onto the arc-shaped curve B, and the laser beam irradiated to the curve B and reflected by the surface of the substrate 20. The intensity of light (reflected light) is continuously measured. The measurement unit 38-1 transmits the data related to the intensity of the obtained reflected light to the calculation unit 38-2 in real time.
The wavelength (predetermined wavelength) of the laser beam irradiated by the side fixing portion 38-1 can be appropriately selected within a range of 405 to 951 nm, for example.
As will be described later with reference to FIG. 4, an arc-shaped curve B coincides with a part of the circumference of a circle D centered on the center C of the susceptor 12.

In the calculation unit 38-2, a diagram to be described later is based on the relationship between the elapsed time from the start of film formation (growth start) of the film 21 and the reflection intensity of the reflected laser light received by the measurement unit 38-1. A graph as shown in FIG.
Thereafter, the amplitude of the reflection intensity is calculated from the graph, and the thickness of the growing film 21 is calculated based on the amplitude of the reflection intensity.

  As the film thickness measuring device 38 configured as described above, for example, a film thickness measuring device that irradiates laser light and obtains the film thickness from the reflection intensity of the laser light can be used. As such a film thickness measuring instrument, for example, EpiCurve TT Two AR manufactured by Laytec can be used.

The control device 41 performs overall control of the vapor phase growth apparatus 10. The control device 41 has a storage unit (not shown). In the storage unit, a program for forming the film 21, a program for controlling the film thickness measuring device 38, and the film 21 A set value or the like stored in advance for obtaining the thickness is stored.
The control device 41 is electrically connected to the source gas supply source 19 and the calculation unit 38-2. The control device 41 stops the supply of the source gas from the source gas supply source 19 when the film 21 having a predetermined thickness is formed on the plurality of substrates 20 placed on the susceptor 12.

FIG. 4 is a plan view for explaining the range of the curve B for measuring the film thickness.
FIG. 5 shows a change in the reflection intensity of the laser beam measured by the film thickness measuring device. The measurement point at which the reflection intensity is measured moves from the point L ₀ where the measurement point generates a trigger according to the rotation of the susceptor. It is a schematic diagram for demonstrating the reflection intensity in each measurement point when doing.
Figure 6 shows the surface temperature and the change of the surface temperature of the susceptor of the substrate, illustrating the surface temperature and the surface temperature of the susceptor of the substrate at each measurement point when the measurement point is moved from the point L ₀ to generate a trigger It is a schematic diagram for doing.

4 to 6, six substrates 20 held on the susceptor 12 are illustrated as substrates 20-1 to 20-6.
A circle D shown in FIG. 4 is a circle centered on the center C of the susceptor 12. Further, L ₀ points shown in Figure 4, is disposed on the susceptor 12 located between the substrate 20-1 and the substrate 20-6, and a point for use in detecting the trigger.
Points L _{0 to} L ₁₀ shown in FIG. 4 are located on the circumference of the circle D at points L ₀ , L ₁ , L ₂ , L ₃ , L ₄ , L ₅ , L ₆ , L ₆ . ₇ , point L ₈ , point L ₉ , and point L ₁₀ are arranged in this order.
The point L ₁ and the point L ₄ are disposed on the edge of the substrate 20-1, and the point L ₁ and the point L ₄ are disposed on the substrate 20-1 located inside the edge of the substrate 20-1. Yes.
A point _{L 5} and the point _{L 8} is arranged at the edge of the substrate 20-2, the points _{L 5} and the point _{L 8} is disposed on the substrate 20-2 that is located inside the edge of the substrate 20-2 Has been.
A point _{L 9} is disposed on the edge of the substrate 20-3, the points _{L 10} is disposed on the substrate 20-3 that is located inside the edge of the substrate 20-3.
5 and 6, the same components as those in FIG. 4 are denoted by the same reference numerals.

  Referring to FIGS. 4 and 5, the surface temperature of the susceptor 12 (specifically, the substrate mounting member 12-5 shown in FIG. 1) located below where the substrates 20-1 to 20-6 are mounted. There is a difference between the surface temperature of the susceptor 12 positioned below the portion where the substrates 20-1 to 20-6 are not disposed.

  Specifically, for example, a silicon substrate (silicon wafer) having a thickness of 725 μm and a diameter of 8 inches (200 mm) is used as the substrates 20-1 to 20-6, the susceptor 12 has a thickness of 20 mm, and SiC. When heating the substrate 20-1 to 20-6 to a predetermined temperature via the susceptor 12 by the heating unit 27 using a susceptor made of coated carbon or silicon carbide (SiC), the substrate 20-1 When the temperature of the susceptor 12 located below where the -20-20 is disposed is 800 ° C., the temperature of the susceptor 12 located below the portion where the substrates 20-1 to 20-6 do not exist is about 770 ° C. Thus, a temperature difference of about 30 ° C. occurs.

That is, the temperature gauge 36 is an edge of the substrate 20-1 located in the vicinity of the point L ₀ from L ₀ point is a position where the measuring point for measuring the temperature detecting the trigger signal of the susceptor 12 (first substrate) the range of the rotational distance to the point _{L 1,} since no substrate 20-1～20-6 exists on the susceptor 12, the surface temperature of the susceptor 12 increases.

On the other hand, rotation from point _{L 1} of the edge of the substrate 20-1 located in the vicinity of the point _{L 0} to a point _{L 4} of the edge of the substrate 20-1 located in the vicinity of the substrate 20-2 (second substrate) Since the substrate 20-1 exists in the distance range, the reflection intensity of the susceptor 12 increases.
Further, in a section from the point _{L 4} of the substrate 20-1 to the point _{L 5} of the edge of the substrate 20-2 located near the point _{L 4,} the reflection intensity of the susceptor 12 is small, the point of the edge of the substrate 20-2 from L ₅ to the point _{L 8} of the edge of the substrate 20-2 located in the vicinity of the substrate 20-3 reflection intensity of the susceptor 12 increases.

  Therefore, as shown in FIG. 6, in order to continuously measure the reflection intensity of the laser beam of the film 21 grown on the plurality of substrates 20-1 to 20-6, the substrates 20-1 to 20-6 are provided. Based on the reflection intensity of the susceptor 12 in the existing part and the reflection intensity of the susceptor 12 in the part where the substrates 20-1 to 20-6 do not exist, the substrates 20-1 to 20-6 exist. Therefore, it is necessary to select the temperature of the susceptor 12 in the portion where the substrate 20-1 to 20-6 is present and to select the reflection intensity of the susceptor 12 in the portion where the substrates 20-1 to 20-6 are present.

  Before starting the sorting operation, for example, the diameter of the susceptor 12 (diameter or radius) and the susceptor 12 are configured in a control device 41 (see FIG. 1) such as a computer that performs arithmetic processing necessary for the sorting operation. The diameter (diameter or radius) of the circle D passing through the center point of the plurality of substrate mounting members 12-5, the diameters (diameter or radius) of the substrates 20-1 to 20-6, and the substrate 20 held by the susceptor 12 A set value determined by the number of sheets of -1 to 20-6 is input in advance.

  A set value determined by the diameter of the susceptor 12, the diameter (diameter or radius) of the circle D, the diameters of the substrates 20-1 to 20-6, and the number of the substrates 20-1 to 20-6 held by the susceptor 12, and a trigger And the susceptor 12 where the substrates 20-1 to 20-6 are not present, and the susceptor 12 where the substrates 20-1 to 20-6 are not present, Can be sorted out.

  For example, the numerical values that are easy to calculate will be specifically described. On the outer periphery of the susceptor 12 having a diameter of 200 mm, four substrates 20 having a diameter of 60 mm are held at equal intervals, and the trajectory passes through the center of the substrate 20. When the circumference of the circle D is 360 mm, when the susceptor 12 makes one turn, the length of the portion where the substrate 20 exists is 240 mm (= 60 mm × 4), and the length of the portion where the substrate 20 does not exist Is 120 mm (= 360 mm−240 mm), and between adjacent substrates 20 is 30 mm (= 120 mm / 4).

Therefore, in this case, due to the rotation of the susceptor 12, the temperature measurement point of the thermometer 36 continuously alternates the 60 mm portion where the substrate 20 exists and the 30 mm portion where the substrate 20 does not exist. And will pass through.
At this time, assuming that the susceptor 12 is rotating at one revolution per minute (1 rpm), the portion in which the substrate 20 is present and the portion in which the substrate 20 is not present in 60 seconds in which the susceptor 12 rotates once. 5 seconds of this occurs alternately four times each.

When the point L _{0 at} which the trigger is generated is set at the outer peripheral edge portion in the rotation direction of the substrate 20, the portion where the substrate 20 exists is passed for 10 seconds after passing the point L ₀ and the portion where the substrate 20 does not exist for the following 5 seconds. These are then repeated alternately.

In FIG. 4, six substrates 20-1 to 20-6 are placed on the susceptor 12, and a point L ₀ that is a position where a trigger signal is generated is adjacent to two substrates 20-1 and 20-6. The case where it arrange | positions to the susceptor 12 located in the center between is shown in figure.

As the set value, for example, in a state where the susceptor 12 is rotating at X (rpm) and the susceptor 12 is rotating at X (rpm), the point from the point L ₀ to the point on the substrate 20-1 after the trigger signal is detected. The reflection intensity measuring device 38 is set to L ₂ (the reflection intensity measurement start point of the first substrate 20-1 positioned immediately after the rotation direction of the susceptor 12 at the position (point L ₀ ) where the trigger signal of the susceptor 12 is detected). The time required for the reflection intensity measurement point to reach E (sec) and the reflection intensity measurement of the reflection intensity measuring device 38 from the point L ₂ to the point L ₃ (the reflection intensity measurement end point of the substrate 20-1) of the substrate 20-1. and the time F required until the point is reached (sec), located in terms _{L 3} of the substrate 20-1 immediately after the rotation direction of the susceptor 12 point _L 5 (1 th substrate 20-1 of the substrate 20 - 2 Start of measurement of reflection intensity of the first substrate 20-2 Time required until the reflection intensity measuring point reflection intensity measuring device 38 reaches a G (sec) in), it can be used.

  As described above, the set values E, F, and G are the diameter of the susceptor 12, the diameter of the circle D through which the center point of the substrate mounting member 12-5 passes, the diameters of the substrates 20-1 to 20-6, and the susceptor. If the number of substrates 20-1 to 20-6 placed on the substrate 12 is determined, it can be easily obtained by calculation.

Note that the rotational speed X of the susceptor 12 is arbitrary, and the actual rotational speed of the susceptor 12 set during processing may be set as a set value, or “1” may be simply set as a set value.
Further, the reason why the outer edge portions of the substrates 20-1 to 20-6 are not set as the reflection intensity measurement start point or the reflection intensity measurement end point is that the positions of the designed substrates 20-1 to 20-6 and the actual substrate 20- The distance from the outer edges of the substrates 20-1 to 20-6 to the reflection intensity measurement start point and the reflection intensity measurement end point is the substrate 20-1 to 20-20. It can be arbitrarily set according to conditions such as a diameter of −6.

  Here, the actual rotation speed Y (rpm) of the susceptor 12 measured after detecting the trigger signal, and the number (n) of substrates 20-1 to 20-6 placed on the susceptor 12 (n is 2 or more) Natural number (n = 6 in the case of FIG. 4), and the rotation speed (set rotation speed) X (rpm), time E (sec), time F (sec) of the susceptor 12 which are the set values described above, and On the basis of the time G (sec), a procedure for measuring the reflection intensity of the laser light of the m-th (m is a natural number of 1 to n) substrates 20-1 to 20-6 after the trigger signal is detected. explain.

First, the time to the measurement point of the reflection intensity of the measuring unit 38-1 to the measurement starting point L ₂ of the reflection intensity at the first substrate 20-1 from the detection trigger signal reaches S _{1 (sec)} is, Correction of the actual rotation speed Y with respect to the time E (sec) and the set rotation speed of the susceptor 12 may be performed, and can be obtained by S ₁ = E / (Y / X). The actual rotational speed (actual rotational speed Y) of the susceptor 12 is measured using the motor 13.

When the set rotational speed X of the susceptor 12 is equal to the actual rotational speed Y of the susceptor 12, S ₁ = E. Further, the time T ₁ (sec) from the detection of the trigger signal to the measurement end point L ₃ of the reflection intensity on the substrate 20-1 is the sum of the time E (sec) and the time F (sec). Therefore, the rotational speed of the susceptor 12 can be corrected, and can be obtained by the following equation (1).
T ₁ = (E + F) / (Y / X) (1)

Time S ₂ (sec) until the reflection intensity measurement point reaches the reflection intensity measurement start point L ₆ on the second substrate 20-1 is time E (sec), time F (sec), and time G The rotation speed of the susceptor 12 may be corrected with respect to the sum of (sec). If the rotation speed of the susceptor 12 is corrected with respect to the sum of the time S ₂ (sec) and the time F (sec), the substrate 20 is corrected. You can determine the time T _{2 (sec)} to the measurement point of the reflection intensity reaches the measurement end point L ₇ of the reflection intensity at -2.

That is, the time S _m until the reflection intensity measurement point reaches the reflection intensity measurement start point on the m-th substrate is the reflection intensity measurement point at the reflection intensity measurement start point of the first substrate 20-1. If the rotational speed of the susceptor 12 is corrected to the sum of the time E (sec) until the time of the reflection and the time F (sec) and the time G (sec) when the reflection intensity measurement point has passed until the m-th sheet is reached. It will be good.

The time T _m until the reflection intensity measurement point reaches the reflection intensity measurement end point on the m-th substrate is the time S _m and time until the reflection intensity measurement point reaches the reflection intensity measurement start point. Since the rotation speed of the susceptor 12 may be corrected to the sum of F (sec), the time S _m until the reflection intensity measurement point reaches the reflection intensity measurement start point on the m-th substrate is as follows. The time T _m until the reflection intensity measurement point reaches the reflection intensity measurement end point on the m-th substrate can be expressed by the following expression (3).

S _m = ((F + G) × (m−1) + E) / (Y / X) (2)
T _m = ((F + G) × (m−1) + E + F) / (Y / X) (3)

For example, the number of substrates is 6 (n = 8), the set rotation speed X of the susceptor 12 is 1 rpm (1 rotation per minute), the time E is 1 sec, the time F is 7 sec, and the time G is 3 sec. When the actual rotation speed Y of the susceptor 12 when the signal is transmitted is 5 rpm, when the measurement of the reflection intensity is started with 0 sec when the trigger signal is detected, the measurement of the reflection intensity is performed at the reflection intensity measurement start point of each substrate. The time when the point reaches (measurement start time) S _m and the time when the reflection intensity measurement point reaches the measurement end point of the reflection intensity of each substrate (measurement end time) T _m are the times shown in Table 1. When the reflection intensity measurement point passes through the sixth substrate 20-6 and a trigger signal is detected, the measurement time is reset and returns to zero.

  In the method for measuring the film thickness of the vapor phase growth apparatus according to the present embodiment, the plurality of substrates 20 are placed at equal intervals in the circumferential direction of the susceptor 12, and the susceptor 12 is rotated while the plurality of substrates 20 is heated. Then, by supplying the source gas into the chamber 11 in which the susceptor 12 is accommodated, the film 21 is grown on the surfaces 20a of the plurality of substrates 20 and grown on the surfaces 20a of the plurality of substrates 20 by the vapor phase growth method. The film 21 is continuously irradiated with a laser beam having a predetermined wavelength in an arc shape, and the thickness of the growing film 21 is continuously increased based on the amplitude of the reflected intensity of the reflected laser light. A region on the substrate 20 that is irradiated with laser light (arc-shaped curve B) is set in advance with the number of rotations of the susceptor 12 when the trigger signal is transmitted, and the susceptor 12. , Substrate 20, and trigger A setting value obtained from a relationship between items, and determines based on (see FIG. 1.).

In the case of FIG. 4, for example, in the case of the first substrate 20-1, the region where the laser light is irradiated and reflected can be a section from the point L ₂ to the point L ₃ (in other words, the curve B). section for irradiating and reflecting the laser beam for the other substrate 20-2～20-6 is a section corresponding from the same period (point _{L 2} and first substrate 20-1 to the point _{L 3,} in other words, the curve B) can be used.
In this way, by irradiating and reflecting the laser beam onto the arcuate curve B of the substrates 20-1 to 20-6 and obtaining the reflection intensity of the reflected laser beams, a plurality of substrates 20-1 to 20- are obtained. 6 can be regarded as one substrate, and the reflection intensity can be continuously acquired.

Further, while the substrates 20-1 to 20-6 exist below the irradiation film thickness measuring device 38, the reflection intensity of the laser light (reflected light) reflected from the substrates 20-1 to 20-6 is continuously acquired. In addition, by treating the data related to the reflection intensity reflected from the plurality of substrates as one data, it is possible to shorten the cycle of measuring the film thickness of the film 21 grown on the substrate 20.
Therefore, even when the rotation speed of the susceptor 12 is slow and the growth speed of the film 21 grown on the substrate 20 is fast, the film thickness measurement period of the film 21 is shortened, so that the reflection intensity of the reflected laser light is reduced. It becomes possible to measure the amplitude correctly.

  Therefore, even when the rotation speed of the susceptor 12 is slow and the growth speed of the film 21 grown on the substrate 20 is high, the thickness of the film 21 during the growth is determined based on the amplitude of the reflected intensity of the reflected laser light. It can be determined accurately.

  The film thickness measurement method of this embodiment is particularly effective when the growth rate of the film 21 is 10 μm / hour or more.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and within the scope of the present invention described in the claims, Various modifications and changes are possible.

(Example)
In the embodiment, as the vapor phase growth apparatus shown in FIG. 1, an MOCVD apparatus (model number: UR26K) manufactured by Taiyo Nippon Sanso Corporation is used, and the surfaces of the six substrates 20-1 to 20-6 shown in FIG. In addition, the thickness of the AlN film when an AlN film having a thickness of 300 nm was grown as the film 21 was obtained.
NH ₃ and TMA were used as source gases. At this time, the supply amount of TMA was set to 10,000 μmol / min.
As the substrates 20-1 to 20-6, silicon substrates (silicon wafers) having a thickness of 725 μm and an outer diameter of 8 inches were used. The temperature of the substrates 20-1 to 20-6 during film formation was set to 1100 ° C. The growth rate of the AlN film was 10 μm / hour.

As the film thickness measuring device 38, EpiCurve TT Two AR which is a film thickness measuring device manufactured by Laytec was used. As the laser light, a semiconductor laser light having a wavelength of 405 nm was used.
Distance for calculating the thickness of each substrate 20-1～20-6 (distance from point _{L 2} on the circumference of a circle D of FIG. 4 to point _{L 3)} was set to 170 mm.

  FIG. 7 shows the relationship between the reflection intensity (au) of the laser beam acquired in the example and the elapsed time (sec).

(Comparative example)
In the comparative example, an MOCVD apparatus (model number: UR26K) manufactured by Taiyo Nippon Sanso Corporation was used as a vapor phase growth apparatus (an apparatus having a susceptor capable of forming films simultaneously on six substrates) started in Patent Document 1. Using this, the thickness of the AlN film when an AlN film having a thickness of 300 nm was grown as a film on the surfaces of the six substrates was obtained.

NH ₃ and TMA were used as source gases. At this time, the supply amount of TMA was set to 1000 μmol / min. That is, in the comparative example, 1/10 of the TMA supply amount of the example was supplied.
As the six substrates, silicon substrates (silicon wafers) having a thickness of 725 μm and an outer diameter of 8 inches were used.

As a trigger described in Patent Document 1, CJ2 (model number), which is a programmable controller device manufactured by OMRON Corporation, was used.
Moreover, as the film thickness measuring device 38, EpiCurve TT Two AR which is a film thickness measuring device made by Laytec was used. As the laser light, a semiconductor laser light having a wavelength of 405 nm was used.
The temperature of the six substrates during film formation was 1100 ° C. The growth rate of the AlN film was 10 μm / hour.

A film thickness measuring device 38 (specifically, EpiCurve TT Two AR (model number) which is a film thickness measuring device manufactured by Raytec) was used. As the laser light, a semiconductor laser light having a wavelength of 405 nm was used.
The same distance as in the example was used as the distance for calculating the film thickness of each substrate.

  FIG. 7 shows the relationship between the reflection intensity (au) of the laser beam acquired in the comparative example and the elapsed time (sec).

Referring to FIG. 7, in the comparative example, the film thickness measurement is performed only at the center of the six substrates, and the film thickness data measured only with the same substrate is handled as one data, so that the susceptor rotation speed is slow. And the period of film thickness measurement becomes longer. For this reason, the number of data of the reflection intensity is reduced, and the amplitude of the reflection intensity is not constant.
As a result, the thickness of the AlN film in the middle of growth could not be obtained accurately based on the amplitude of the reflection intensity of the laser light of the comparative example.

On the other hand, in the embodiment, the substrate 20-1 to 20-6 is not a point but a predetermined region (the region of the substrate 20-1 corresponding to the curve B) by using the reflected intensity of the reflected laser beam, Since the acquired reflection intensity data of the plurality of substrates 20-1 to 20-6 is handled as one data, the number of reflection intensity data is larger than that of the comparative example, and the amplitude of the reflection intensity is constant.
From this, it was confirmed that the thickness of the film 21 during the growth can be accurately obtained from the amplitude of the reflection intensity of the laser light of the example.

  The present invention is applicable to a film thickness measuring method for a vapor phase growth apparatus that can measure the thickness of a film grown by a vapor phase growth method using a self-revolving vapor phase growth apparatus.

DESCRIPTION OF SYMBOLS 10 ... Vapor growth apparatus, 11 ... Chamber, 11-1 ... Chamber main body, 11-2 ... Opening part, 11-3 ... Through part, 11-4 ... Light transmissive window member, 12 ... Susceptor, 12-1 ... Susceptor body, 12-1a, 12-3a, 12-5a, 14a ... upper surface, 12-1b ... lower surface, 12-2 ... penetration, 12-3 ... ring-shaped fixing member with external gear, 12-3A ... external gear 12-3B ... accommodating section, 12-4 ... ball, 12-5 ... substrate mounting member, 12-5b ... substrate mounting surface, 12-5A ... substrate accommodating section, 13 ... rotating shaft, 14 ... with internal gear Ring-shaped fixing member, 14-1 ... Ring-shaped member, 14-2 ... Internal gear section, 15 ... Motor, 17 ... Gas supply section, 17A ... Source gas supply port, 19 ... Source gas supply source, 20, 20-1 -20-6 ... substrate, 20a ... front surface, 20b ... back surface, 21 ... film, 23 ... gas 23-1 ... first guide member, 23-2 ... second guide member, 25 ... heating part accommodating part, 27 ... heating part, 29 ... inert gas outlet part, 32 ... inert gas introducing part 34 ... Exhaust part, 36 ... Thermometer, 38 ... Film thickness measuring device, 38-1 ... Measurement part, 38-2 ... Calculation part, 41 ... Control device, A ... Area, B ... Curve, C ... Center, D ... yen, L _{0 to} L ₁₀ ... points

Claims (5)

Placing a plurality of substrates at equal intervals in the circumferential direction of the susceptor, and rotating the susceptor in a state where the plurality of substrates are heated;
By supplying a source gas into the chamber in which the susceptor is accommodated, a film is grown on the surfaces of the plurality of substrates by a vapor phase growth method, and the films grown on the surfaces of the plurality of substrates are grown. Irradiating a laser beam having a predetermined wavelength continuously in an arc shape, and continuously acquiring the thickness of the growing film based on the amplitude of the reflected intensity of the reflected laser beam; ,
Including
A region on the substrate that is irradiated with the laser light is set in advance from the relationship between the number of rotations of the susceptor when a trigger signal is transmitted and the susceptor, the substrate, and the trigger signal. value, determined based on,
Treat each data of the reflection intensity reflected from the plurality of substrates as data of the reflection intensity reflected from one substrate,
A film for a vapor phase growth apparatus characterized in that a cycle for measuring the thicknesses of the films grown on the surfaces of the plurality of substrates is shorter than a case where the reflection intensity measured only on the same substrate is treated as one data. Thickness measurement method.   In the step of continuously acquiring the thickness of the film, the region on the substrate to be irradiated with the laser light is a circle having a center that coincides with the center of the susceptor among the surfaces of the plurality of substrates. 2. The method of measuring a film thickness of a vapor phase growth apparatus according to claim 1, wherein a region through which the gas passes is used.   The set value is one sheet positioned immediately after the rotation direction of the susceptor at the position where the trigger signal of the susceptor is detected in a state where the rotation speed X of the susceptor and the susceptor are rotating at the rotation speed X. The time E required until the film thickness measurement point of the film thickness measuring device reaches the film thickness measurement start point of the substrate of the eye, and the film thickness measurement start point to the film thickness measurement end point of the first substrate Time F required for the film thickness measuring point of the film thickness measuring device to reach and two sheets positioned immediately after the film thickness measurement end point of the first substrate immediately after the rotation direction of the susceptor of the first substrate The film of the vapor phase growth apparatus according to claim 1, wherein the time G is required until the film thickness measurement point of the film thickness measuring device reaches the film thickness measurement start point of the substrate of the eye. Thickness measurement method.   The method for measuring a film thickness of a vapor phase growth apparatus according to any one of claims 1 to 3, wherein a growth rate of the film is 10 µm / hour or more.   5. The method for measuring a film thickness of a vapor phase growth apparatus according to claim 1, wherein the plurality of substrates placed on the susceptor are rotated during the growth of the film. .

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