JP2011249516A - Deposition device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deposition device which can minimize the effect on the crystallinity of a thin film even if a through hole is made through a gas guide plate, and can minimize deposition of reaction products on other components.SOLUTION: On an MOCVD device 100 which deposits a film on the surface of a substrate to be deposited by supplying reaction gas comprises a substrate holding stand 3, a gas guide plate 6 is arranged to face the substrate holding stand 3 and having a through hole 7 at a position facing the surface of the substrate 2 to be deposited, and reaction gas piping 8 is mounted through which reaction gas 8a is fed between the substrate holding stand 3 and the gas guide plate 6. On the side of the gas guide plate 6 facing the substrate 2, the shortest distance of a downstream side end 13, which touches the through hole 7 on the downstream side of gas flow, to the surface of the substrate 2 to be deposited is longer than that of an upstream end 12 which touches the through hole 7 on the upstream side of gas flow. Therefore the reaction gas 8a flowing out through the through hole 7 is suppressed.

Description

  The present invention relates to a film forming apparatus such as an MOCVD apparatus for crystal growth using a gas on a substrate.

  A MOCVD (Metal Organic Chemical Vapor Deposition) apparatus is suitably used for the production of compound semiconductors such as semiconductor laser elements and LED (Light Emitting Diode) elements.

  In general, in an MOCVD apparatus, a compound semiconductor crystal is grown on a substrate by introducing a reaction gas into a reaction chamber and heating it to cause a gas phase reaction on the substrate. In order to perform crystal growth on the substrate with good reproducibility, it is necessary to keep the substrate temperature at a predetermined temperature and supply the reaction gas onto the substrate with a uniform concentration distribution and flow rate. For this reason, it is desirable to advance crystal growth while measuring and confirming the warpage and temperature of the substrate during the crystal growth process.

  In order to measure the warpage and temperature of the substrate, a viewport is usually provided on the outer wall of a reaction chamber such as a box or cylinder called a chamber that contains the reaction gas and prepares the process environment. It is common to make the above measurements through this viewport.

  For example, when measuring the warpage of a substrate, the warpage measuring device emits measurement light, irradiates the surface of the substrate through the viewport, and receives reflected light from the substrate. When the substrate is warped, the measurement light is reflected with a certain reflection angle according to the warp of the substrate, so that the light receiving position of the light receiving unit differs depending on whether the warp of the substrate is small or large. The warpage measuring device measures the warpage of the substrate using the difference in the light receiving position.

  By the way, in the MOCVD apparatus, a gas guide plate is often provided in order to flow the reaction gas near the substrate efficiently. The gas guide plate is a partition wall that divides the upper space on the film formation surface side of the substrate into a space on the substrate side and a space on the inner wall side of the reaction chamber. In an MOCVD apparatus provided with a gas guide plate, a through hole is provided in the gas guide plate in order to measure the warpage and temperature of the substrate during film formation, and the surface to be processed of the substrate from the view port through the through hole. Can be seen.

  For example, the MOCVD apparatus disclosed in Patent Document 1 will be briefly described.

  8A is a side view showing the MOCVD apparatus 201 of Patent Document 1, FIG. 8B is a top view thereof, and FIG. 8C is a cross-sectional view thereof. As shown in FIGS. 8A to 8C, in the MOCVD apparatus 201, the substrate 206 is placed on the susceptor 205 on the inner side of the outer tube wall 201 and the inner tube wall 203 constituting the double structure. The outer tube wall 201 is provided with a light transmitting window 202, and the inner tube wall 203 is provided with a hole 204 through which light passes. Therefore, the MOCVD apparatus 201 can irradiate the substrate 206 with light 209 through the window 202 and the hole 204.

JP 62-188218 A (published August 17, 1987)

  However, in a conventional MOCVD apparatus in which a through hole is provided in the gas guide plate, the pressure in the space on the substrate side is higher than the pressure in the space on the inner wall side of the reaction chamber in the upper space on the deposition surface side of the substrate. If it is high, the reaction gas does not stay in the space on the substrate side, but blows out to the inner wall side of the reaction chamber through the through hole. As a result, the crystallinity of the thin film obtained on the substrate may be adversely affected.

Further, when the blown-out reaction gas reaches the vicinity of the viewport, the reaction product is accumulated in the viewport, and the measurement light for measuring the warpage and temperature of the substrate is reflected by the reaction product. . As a result, the data obtained from the warpage of the substrate and the temperature measurement becomes a value different from the value that should originally be obtained.
For this reason, it is necessary to frequently change and clean the viewport.

  Furthermore, not only the viewport but also other components such as a heater and a drive unit cause problems when the reaction products accumulate, and replacement and cleaning of these components are frequently required.

  The present invention has been made in view of the above problems, and its purpose is to suppress the influence on the crystallinity of the thin film and react to other parts even if the gas guide plate has a through hole. An object of the present invention is to provide a film forming apparatus capable of suppressing the accumulation of products.

  In order to solve the above problems, a film forming apparatus according to the present invention is a film forming apparatus that supplies a reaction gas to form a film formation surface of a substrate, and includes a substrate holder that holds the substrate, A gas guide plate disposed opposite to the substrate and having a through hole at a position facing the substrate; and a gas supply means for flowing the reaction gas between the substrate holder and the gas guide plate. On the side of the gas guide plate facing the substrate, the downstream end that contacts the through hole on the downstream side of the gas flow by the reaction gas is the upstream end that contacts the through hole on the upstream side. The shortest distance from the film formation surface of the substrate is longer than that.

  In the above configuration, the gas guide plate defines the flow path of the reaction gas so that the reaction gas supplied by the gas supply means flows toward the film formation surface of the substrate on the holding table. Further, the gas guide plate is formed with a through hole at a position facing the film formation surface so that the film formation surface of the substrate can be seen from the outside, for example.

  According to the above configuration, the reactive gas that flows toward the substrate flows between the substrate and the through hole. Since the distance between the downstream end and the substrate in the gas guide plate is larger than the distance between the upstream end and the substrate, the cross-sectional area of the flow path of the reaction gas flowing between the substrate and the through hole is the through hole. It is larger on the downstream side than on the upstream side. That is, the pressure of the reaction gas decreases from the upstream side to the downstream side of the through hole. For this reason, the reactive gas easily flows from the upstream side to the downstream side of the through hole. Accordingly, it is possible to suppress the reaction gas from being blown out from the space between the gas guide plate and the substrate through the through hole.

  Therefore, in the film forming apparatus according to the present invention, changes in the gas concentration distribution and flow rate on the substrate can be suppressed, and the influence on the crystallinity of the resulting thin film can be suppressed. In addition, even if viewports and other parts are placed on the opposite side of the substrate across the gas guide plate, the proportion of contact between these parts and the reactive gas will decrease, so problems due to reaction products will occur. The frequency of replacement and cleaning can be reduced.

  The film forming apparatus according to the present invention preferably includes a reaction chamber that accommodates the substrate, and a viewport that is provided on a wall of the reaction chamber and can face the film formation surface through the through hole.

  In the above structure, the substrate being formed in the reaction chamber can be observed and measured through the view port and the through hole. According to the above configuration, since the rate at which the reaction gas reaches the viewport is reduced, the reaction product is suppressed from being deposited in the viewport. Therefore, accurate data can be obtained in the measurement of the warpage and temperature of the substrate during film formation. Also, the frequency of viewport replacement and cleaning can be reduced.

  In the film forming apparatus according to the present invention, the gas guide plate includes the downstream end on the side facing the substrate, and the shortest distance from the film forming surface of the substrate with respect to the upstream end. It is preferable to have an arbitrary step region that is long.

  According to the above configuration, the reaction gas that has flowed toward the substrate flows between the substrate and the through hole and further flows toward the region. The cross-sectional area of the flow path through which the reaction gas flows is larger than the upstream side of the through hole in the space in contact with the region on the downstream side. For this reason, it becomes easier for the reactive gas to flow toward the downstream side of the through hole. Therefore, it can suppress more effectively that reactive gas blows off through the through-hole from the space between a gas guide plate and a board | substrate.

  In the film forming apparatus according to the present invention, it is preferable that the downstream end of the gas flow in the step region is downstream of the downstream end of the gas flow in the substrate.

  In the above configuration, on the side of the gas guide plate facing the substrate, when the shortest distance from the deposition surface of the substrate is shorter on the downstream side than the region, when the reaction gas flows downstream from the region, The cross-sectional area of the reaction gas is reduced. At this time, since the pressure of the reaction gas increases, the reaction gas is accumulated on the downstream side in the region.

  However, according to the above configuration, the downstream end position in the region is downstream of the downstream end of the substrate. For this reason, the space where the above-mentioned puddle is located is located on the downstream side of the substrate, and the influence of the puddle of the reaction gas on the substrate can be reduced.

  Furthermore, in the film forming apparatus according to the present invention, the gas guide plate has a shortest distance from the film formation surface of the substrate toward the downstream side of the gas flow at a position in contact with the end of the step region. It is preferable to have an inclined surface.

  According to the above configuration, the cross-sectional area of the reaction gas flowing from the region toward the inclined surface gradually decreases. For this reason, the pressure of the reaction gas gradually changes. As a result, it is possible to suppress the puffing of the reaction gas and to suppress the change in the concentration distribution of the reaction gas on the substrate.

  Further, in the film forming apparatus according to the present invention, the gas guide plate includes the downstream end portion, and an inclined surface in which the shortest distance from the film forming surface of the substrate is shortened toward the downstream of the gas flow. You may have.

  According to the above configuration, the cross-sectional area of the reaction gas flowing in the vicinity of the inclined surface gradually decreases. For this reason, the pressure of the reaction gas gradually changes. As a result, it is possible to suppress the puffing of the reaction gas and to suppress the change in the concentration distribution of the reaction gas on the substrate.

  A film forming apparatus according to the present invention is a film forming apparatus for supplying a reaction gas to form a film formation surface of a substrate, and on the side of the gas guide plate facing the substrate, the gas flow is downstream of the through hole. The downstream end that is in contact with the side has a shortest distance from the deposition surface of the substrate longer than the upstream end that is in contact with the upstream side. For this reason, even if the gas guide plate has a through hole, it is possible to suppress the influence on the crystallinity of the thin film and to prevent the reaction product from being deposited on other parts.

(A) is sectional drawing, the schematic structure of the MOCVD apparatus which concerns on this embodiment, (b) is a top view which shows the through-hole, (c) is sectional drawing which shows the through-hole. (A) is sectional drawing which shows the modification of the through-hole shown in FIG. 1, (b) is the top view, (c) is the expanded sectional view. (A) is sectional drawing which shows the other modification of the through-hole shown in FIG. 1, (b) is the top view, (c) is the expanded sectional view. (A) is sectional drawing which shows the other modification of the through-hole shown in FIG. 1, (b) is the top view, (c) is the expanded sectional view. It is sectional drawing which shows the principal part structure of the MOCVD apparatus which concerns on an Example. (A) is sectional drawing which shows the principal part structure of the conventional MOCVD apparatus, (b) is a top view which shows the through-hole, (c) is sectional drawing which shows the through-hole. It is a table | surface which shows the analysis result of an Example and a comparative example. (A) is the side view which shows the MOCVD apparatus of patent document 1, (b) is the top view, (c) is the sectional drawing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.

(Configuration of MOCVD apparatus 100)
First, the configuration of the MOCVD apparatus (film forming apparatus) 100 according to the present embodiment will be described with reference to FIG. FIG. 1A is a cross-sectional view showing a schematic configuration of the MOCVD apparatus 100 according to the present embodiment.

  As shown in FIG. 1A, an MOCVD apparatus 100 includes a chamber 1, a holding table 3 that holds a substrate 2, a rotating table 4 that rotates the substrate 2, and a heater that is disposed below the holding table 3 as a heating means. 5, a gas guide plate 6, a reaction gas pipe 8 that supplies a reaction gas 8 a, a purge gas pipe 9 that supplies a purge gas 9 a, and a measuring device 11.

  The chamber (reaction chamber) 1 is a container for supplying a reaction gas 8 a to grow crystals on the surface to be processed of the substrate 2. A view port 10 is formed in the chamber 1 so as to be able to face the film formation surface of the substrate 2 disposed inside. The viewport 10 is made of a transparent material that can transmit light.

  A plurality of holding tables (substrate holding tables) 3 are arranged at equal intervals with respect to the rotating table 4, and the substrate 2 is arranged on the upper surface thereof. The turntable 4 has a rotation shaft (not shown), and rotates the substrate 2 disposed on the holding stand 3 by being driven by a motor (not shown). Thereby, the thickness of the thin film between the plurality of substrates 2 can be made uniform.

  In the present embodiment, the holding table 2 holds the substrate 2 so that the film formation surface of the substrate 2 and the upper surface of the turntable 4 are on the same plane.

  The heater 5 can raise the temperature of the substrate 2 to a maximum of about 1300 ° C. during the film formation process, and this heat causes a gas phase reaction in the reaction gas 8a. At this time, a crystal thin film corresponding to the component of the reaction gas 8a is formed on the substrate 2.

  The gas guide plate 6 is disposed to face the upper surfaces of the holding table 3 and the rotating table 4. The gas guide plate 6 has a structure that partitions the reaction gas 8a and the purge gas 9a and allows the reaction gas 8a to flow only in the vicinity of the substrate 2. The gas guide plate 6 is provided with a through hole 7 at a position facing the central portion of the substrate 2. The shape of the gas guide plate 6 around the through hole 7 will be described in detail later.

  The reaction gas pipe (gas supply means) 8 is connected to a reaction gas source, and the gas outlet is disposed between the gas guide plate 6 and the turntable 4 in the center of the chamber 1. For this reason, the reaction gas 8 a supplied from the reaction gas pipe 8 flows radially from the center of the chamber 1 between the gas guide plate 6 and the turntable 4. The reaction gas 8a is made of a raw material component such as trimethylgallium, trimethylaluminum, trimethylindium, or ammonia and a carrier such as hydrogen or nitrogen. In the following description, “gas flow” means the flow of the reaction gas 8a.

  On the other hand, the purge gas pipe 9 is connected to a purge gas supply source, and the gas outlet is disposed between the inner wall of the chamber 1 and the gas guide plate 6 at the center of the chamber 1. Therefore, the purge gas 9 a supplied from the purge gas pipe 9 flows radially from the center of the chamber 1 between the inner wall of the chamber 1 and the gas guide plate 6. The purge gas 9a may be any gas that does not contain a reaction gas, and for example, hydrogen or nitrogen can be suitably used.

  The measuring device 11 is disposed directly above the view port 10 outside the chamber 1. During the film formation, the measuring device 11 irradiates the film formation surface of the substrate 2 disposed in the chamber 1 through the view port 10 and the through hole 7 and irradiates the light reflected by the substrate 2. By receiving light, the warp or temperature of the substrate 2 during crystal growth can be measured.

(Conventional gas guide plate 106)
Next, the gas guide plate 106 in the conventional MOCVD apparatus will be described with reference to FIG. FIG. 6A is a cross-sectional view showing a configuration of a main part of a conventional MOCVD apparatus, FIG. 6B is a top view showing a through hole 107 of a gas guide plate 106 in the conventional MOCVD apparatus, and FIG. It is sectional drawing which shows the through-hole 107 in the surface containing the centerline of the through-hole 107 and parallel to a gas flow rate direction.

  As shown in FIG. 6, in the conventional MOCVD apparatus, the distance between the film formation surface of the substrate 102 and the gas guide plate 106 is constant between the upstream side and the downstream side of the through hole 7. Therefore, when the pressure between the gas guide plate 106 and the substrate 102 is higher than the pressure between the gas guide plate 106 and the chamber wall (not shown), as shown by the arrow in FIG. The reaction gas 108 is blown out through the through hole 107. As a result, the crystallinity of the thin film obtained is adversely affected, and a reaction product is deposited in a viewport (not shown).

(Gas guide plate 6 of this embodiment)
Next, the gas guide plate 6 in the MOCVD apparatus 100 according to the present embodiment will be described with reference to FIGS. FIG. 1B is a top view showing the through hole 7 of the gas guide plate 6, and FIG. 1C is a cross section showing the through hole 7 in a plane that includes the center line of the through hole 7 and is parallel to the gas flow rate direction. FIG.

  In the following description, the upstream side of the gas flow is referred to as “upstream side”, and the downstream side of the gas flow is referred to as “downstream side”. In the following description, when simply referred to as “reactive gas 8a”, the reactive gas 8a flowing between the substrate 2 and the through hole 7 will be described unless otherwise specified.

  As shown in FIGS. 1B and 1C, the gas guide plate 6 is bent along each of a line passing through the through hole 7 and a line in contact with the periphery of the through hole 7. As a result, a step region 6 a having a step d between the downstream side of the through hole 7 and the downstream side of the through hole 7 is formed in the gas guide plate 6.

  Here, as shown in FIG. 1 (c), among the end portions constituting the edge of the through hole 7 on the surface of the gas guide plate 6 facing the base 2, the upstream end portion, that is, the reaction gas pipe 8. The end closest to the gas outlet is defined as the upstream end 12. Further, the downstream end, that is, the end farthest from the gas outlet of the reaction gas pipe 8 is defined as the downstream end 13. The downstream end 13 is included in the step region 6a. At this time, regarding the shortest distance between the surface of the gas guide plate 6 on the substrate 2 side and the surface of the substrate 2, the distance at the downstream end 13 is longer than the distance at the upstream end 12.

  According to the above configuration, since the cross-sectional area of the reaction gas 8 a increases from the upstream side to the downstream side of the through hole 7, the pressure of the reaction gas 8 a decreases from the upstream side to the downstream side of the through hole 7. is doing. For this reason, the reactive gas 8a is likely to flow from the upstream side to the downstream side of the through hole 7.

  As a result, the reaction gas 8a is difficult to blow out through the through hole 7 of the gas guide plate 6, and the rate at which the reaction gas 8a reaches the viewport 10 is also reduced. Therefore, changes in the concentration distribution and flow rate of the reaction gas 8a on the substrate 2 can be suppressed, and adverse effects on the crystallinity of the thin film obtained on the film formation surface of the substrate 2 can be suppressed.

  Further, since the ratio of the reaction gas 8a reaching the viewport 10 can be reduced, it is possible to suppress the reaction product from being deposited on the viewport 10. For this reason, the measuring apparatus 11 can accurately measure the warp, temperature, and the like of the substrate 2 during film formation without the measurement light being hindered by the deposit. Further, the frequency of replacement and cleaning of the viewport 10 can be reduced.

  Furthermore, since the rate at which the reaction gas 8a arrives can be reduced for parts that become a problem when the reaction product accumulates, for example, a heater and a drive unit, the replacement and cleaning of these members can be performed. The frequency can be reduced.

(Other examples of gas guide plate 6)
The shape of the end including the downstream end 13 of the gas guide plate 6 can be variously modified. Another example of the gas guide plate 6 will be described with reference to FIGS.

  In addition, each modification described below and the above-described embodiment are such that the distance at the downstream end 13 is the upstream end with respect to the shortest distance between the surface of the gas guide plate 6 on the substrate 2 side and the surface of the substrate 2. It is common in the point which becomes longer than the distance in the part 12. FIG. For this reason, all the effects of this embodiment mentioned above are applied also to the following modifications.

  As shown in FIG. 2, the gas guide plate 6 includes a step region 6 b that includes a downstream end 13 and a step with the upstream end 12 on the side facing the substrate 2. Also good. Note that the step region 6b can be realized by thinning an arbitrary region in the gas guide plate 6. According to this modification, since only the step region 6b has to be processed in the gas guide plate 6, the processing cost can be suppressed.

  In the modification shown in FIG. 2, when the reaction gas 8a flows further downstream from the step region 6b, the flow path cross-sectional area of the reaction gas 8a decreases, so the pressure of the reaction gas 8a increases. As a result, the reaction gas 8a is accumulated on the downstream side of the step region 6b. However, according to the present modification, the downstream end of the step region 6b is downstream from the downstream end of the substrate 2 in the flow direction of the reaction gas 8a. For this reason, the space where the puddle occurs is on the downstream side of the substrate 2, and the influence of the puddle of the reaction gas 8 a on the substrate 2 can be reduced.

  Further, as shown in FIG. 3, the gas guide plate 6 has a step region 6c having the same configuration as the step region 6b on the side facing the substrate 2, and an inclination formed on the downstream side of the step region 6c. And may have a surface 14. According to this modification, since the step region 6c and the inclined surface 14 need only be processed in the gas guide plate 6, the processing cost can be suppressed.

  In the modification shown in FIG. 3, the cross-sectional area of the reaction gas 8a in the space near the inclined surface 14 gradually decreases toward the downstream. For this reason, when the reaction gas 8a flows downstream from the step region 6c, the pressure of the reaction gas 8a gradually changes. As a result, it is possible to suppress the accumulation of the reaction gas 8a and to suppress the change in the concentration distribution of the reaction gas on the substrate 2.

  As shown in FIG. 4, the gas guide plate 6 may have an inclined surface 15 including a downstream end portion 13 on the side facing the substrate 2. According to the present embodiment, since the range where the gas guide plate 6 needs to be processed is smaller than the modification shown in FIGS. 2 and 3, the cost associated with the processing can be further suppressed.

  In the modification shown in FIG. 4, the downstream end position of the inclined surface 15 is between the center position of the substrate 2 and the downstream end in the flow direction of the reaction gas 8a. Even in such a structure, the cross-sectional area of the reaction gas 8a in the space near the inclined surface 15 gradually decreases toward the downstream. For this reason, when the reaction gas 8a flows downstream of the through hole 7, the pressure of the reaction gas 8a gradually changes. As a result, it is possible to suppress the accumulation of the reaction gas 8a and to suppress the change in the concentration distribution of the reaction gas on the substrate 2.

  Note that the shape of the step region 6a on the plane of the gas guide plate 6 is not limited to the shape illustrated in the drawings, and may be any region that extends from the downstream end 13 to the downstream side of the gas flow. Moreover, it does not specifically limit about the magnitude | size of a level | step difference, For example, 1 mm may be sufficient and 10 mm may be sufficient.

  In the present embodiment, the shape and size of the through hole 7 of the gas guide plate 6 is such that the radiation and reflection from the substrate 2 can be directly observed when the measuring device 11 measures the temperature and warpage of the substrate 2. There is no particular limitation, and any shape or size may be used. Further, in the gas guide plate 6, the surface on which the reactive gas 8 a does not flow (the surface facing the inner wall of the chamber 1) may not coincide with the upstream side and the downstream side of the through hole 7.

  Next, the effects of the present invention will be described with reference to examples, but the present invention is not limited to the following examples.

  The MOCVD apparatus 100 according to the present embodiment was used as an example, and the MOCVD apparatus according to the related art was used as a comparative example to simulate the reaction gas flow velocity in the vicinity of the through hole of the gas guide plate.

  FIG. 5 is a diagram showing a main configuration of the MOCVD apparatus 100 used as an example. As shown in FIG. 5, the gas guide plate 6 has a step region 6b. The length 1 of the through hole 7 in the flow velocity direction of the reaction gas 8a is 3 mm. The thickness t of the upstream side of the through hole 7 in the gas guide plate 6 is 5 mm, and the step d of the step region 6b on the downstream side is 1 mm. Further, the downstream end of the step region 6b is downstream from the end of the substrate 2 in the direction of the flow rate of the reaction gas 8a.

  On the other hand, the comparative example has the configuration shown in FIG. The gas guide plate 106 does not have a step, and the gap between the gas guide plate 6 and the substrate 2 is the same. The thickness of the gas guide plate 106 is 5 mm. The length of the through hole 107 in the flow velocity direction of the reaction gas 108 is 3 mm as in the example.

  As simulation conditions for the examples and comparative examples, the flow rate of the reaction gas supplied to the MOCVD apparatus was 4.5 m / s, and the flow rate of the purge gas was 0.0075 m / s. The simulation was performed in two dimensions, and the shape of the through hole in the depth direction was a slit shape.

  In the simulation, the maximum value of the flow velocity in the normal direction with respect to the film formation surface of the substrate immediately above the through hole of the gas guide plate was measured. The result is shown in FIG.

  As shown in FIG. 7, in the example, the maximum flow velocity in the normal direction with respect to the film formation surface of the substrate 2 immediately above the through hole 7 was 0.07 m / s. The pressure immediately below the through hole 7 was 0.38 Pa, and the pressure just above the through hole 7 was 0.23 Pa.

  On the other hand, in the comparative example, the maximum flow velocity in the normal direction with respect to the film formation surface of the substrate 102 immediately above the through hole 107 was 0.31 m / s. The pressure immediately below the through hole 107 was 0.63 Pa, and the pressure just above the through hole 107 was 0.29 Pa.

  According to the above results, in the example, compared with the comparative example, the flow rate of the reaction gas 8a in the normal direction with respect to the deposition surface of the substrate 2 immediately above the through hole 7 is suppressed to ¼ or less. I found out that This indicates that the pressure immediately below the through hole 107 is reduced, so that the reactive gas 8a is effectively suppressed from being blown out through the through hole 7 to the viewport 10 side.

  Thereby, the rate at which the reaction gas 8a reaches the viewport 10 also decreases, and the frequency of replacement and cleaning of the viewport 10 can be reduced to ¼ or less. Further, changes in the gas concentration distribution and flow rate on the substrate 2 can be suppressed, and the influence on the crystallinity of the resulting thin film can be suppressed.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible in the range shown to the claim.

  The present invention can be suitably used as a film forming apparatus used in the compound semiconductor field.

DESCRIPTION OF SYMBOLS 1 Chamber 2 Board | substrate 3 Holding stand 4 Turntable 5 Heater 6 Gas guide plate 6a-6c Step area 7 Through-hole 8 Reactive gas piping 8a Reactive gas 9 Purge gas piping 9a Purge gas 10 Viewport 11 Measuring apparatus 12 Upstream side end 13 Downstream side Ends 14 and 15 Inclined surface 100 MOCVD apparatus

Claims (6)

A film forming apparatus for forming a film formation surface of a substrate by supplying a reaction gas,
A substrate holder for holding the substrate;
A gas guide plate disposed opposite to the substrate and having a through hole at a position facing the substrate;
Gas supply means for flowing the reaction gas between the substrate holder and the gas guide plate;
On the side of the gas guide plate facing the substrate, the downstream end that contacts the through hole on the downstream side of the gas flow by the reaction gas is the upstream end that contacts the through hole on the upstream side. A film forming apparatus characterized in that the shortest distance from the film formation surface of the substrate is longer. A reaction chamber containing the substrate;
The film forming apparatus according to claim 1, further comprising: a viewport provided on a wall of the reaction chamber and capable of facing the film formation surface through the through hole.   The gas guide plate has an arbitrary step region including the downstream end on the side facing the substrate and having a shortest distance from the deposition surface of the substrate longer than the upstream end. The film forming apparatus according to claim 1, wherein:   The film deposition apparatus according to claim 3, wherein the downstream end of the gas flow in the stepped region is located downstream of the downstream end of the gas flow in the substrate.   The gas guide plate has an inclined surface at a position in contact with the downstream end of the step region, and the shortest distance from the film formation surface of the substrate becomes shorter toward the downstream of the gas flow. The film forming apparatus according to claim 3 or 4. 4. The gas guide plate according to claim 3, wherein the gas guide plate includes an inclined surface that includes the downstream end portion and has a shortest distance from the film formation surface of the substrate that decreases toward the downstream side of the gas flow. The film-forming apparatus of description.

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