JP2016047938A - Vapor deposition apparatus and support structure for treated substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vapor deposition apparatus which prevents particulates inside a reaction chamber from swirling up and does not use a lift pin, and to provide a susceptor support structure capable of transferring a treated substrate without using the lift pin.SOLUTION: A vapor deposition apparatus 1 includes a susceptor 3 having a mounting surface for mounting a wafer W thereon, and a reaction chamber 2 for performing vapor deposition on the wafer W mounted on the mounting surface. The susceptor 3 can be elastically deformed from a horizontal state where the mounting surface is horizontal or approximately horizontal, to a curved surface where the mounting surface is protruded upward. When the wafer W is mounted on a protrusion C of the curved surface, the outer peripheral part of the wafer W and the mounting surface are separated, therefore, when transferring the wafer W between a conveyance robot 12 that supports the outer peripheral part of the wafer W and the susceptor 3, contact between the conveyance robot 12 and the susceptor 3 can be avoided.SELECTED DRAWING: Figure 3D

Description

  The present invention relates to a vapor phase growth apparatus and a substrate support structure.

  Patent Document 1 discloses a typical lamp heating type silicon epitaxial growth apparatus 101 (see FIGS. 6A and 6B). In the apparatus 101, a substrate to be processed W 'such as a silicon substrate is supported by a rotatable susceptor 103, and a reaction vessel 102 (see FIG. 6B) is formed airtight so as to surround the susceptor 103. A gas introduction pipe 110 is connected to one end side (left side in the figure) of the reaction vessel 102, and a gas discharge pipe 111 is connected to the opposite side (right side in the figure). On the other hand, a lamp L and a blower (not shown) are provided outside the reaction vessel 102. At the time of vapor phase growth, the vapor phase growth gas is introduced into the reaction vessel 102 from the gas introduction tube 110 while the target substrate W ′ is heated by the lamp L, and an epitaxial layer is formed on the silicon substrate. 111 is discharged. Further, the wall of the reaction vessel 102 is cooled by a blower so that the vapor phase growth gas does not cause unnecessary reaction, and is maintained at a temperature lower than that of the silicon substrate.

  Prior to vapor phase growth, the substrate to be processed W ′ is transferred by the lamp L to the reaction vessel 102 maintained at a temperature of about 900 ° C. (a temperature at which the substrate W ′ is not defective due to thermal shock). The substrate to be processed W ′ is transported by the transport robot and placed on the susceptor 103 in the reaction container 102. Then, after the epitaxial growth process is performed on the substrate to be processed W ′, the substrate to be processed W ′ on the susceptor 103 is picked up by the transfer robot and unloaded from the reaction vessel 102.

  Thus, the method of carrying in / out the substrate to be processed to / from the reaction vessel is substantially described below in view of the high temperature of the reaction vessel and the restriction that impurities such as metal atoms should not be mixed in the reaction vessel. There are only two ways.

  The first method is a method in which the substrate to be processed is carried into and out of the reaction container in a state where the substrate to be processed is adsorbed on the lower surface of the robot arm of the transfer robot. When transferring the substrate to be processed from the robot arm to the susceptor, the robot arm releases the substrate to be processed and drops the substrate to be processed from above the susceptor. Further, when the robot arm receives the substrate to be processed on the susceptor, the robot arm sucks the substrate to be processed placed on the susceptor.

  There are two methods for adsorbing the substrate to be processed by the robot arm: a method using a vacuum pump and a method using the Bernoulli effect. However, the former has a high risk of damaging the surface of the substrate to be processed. Even in the latter case, there is a problem that fine particles in the reaction vessel are rolled up and adhered to the surface of the substrate to be processed by blowing a large amount of gas on the substrate to be processed.

  The second method for loading / unloading the substrate to / from the reaction container is a method for loading / unloading the substrate to be processed by placing it on the top surface of the robot arm tip. When the substrate to be processed is transferred from the robot arm to the susceptor, the substrate to be processed placed on the robot arm is lifted by a lift pin inserted into a small hole penetrating in the thickness direction of the susceptor. Then, with the substrate to be processed being lifted, the robot arm is withdrawn, the lift pins are lowered, and the substrate to be processed is lowered (placed) on the susceptor. When the robot arm receives the substrate to be processed from the susceptor, the substrate to be processed is transferred from the susceptor to the robot arm in the reverse procedure.

JP 2014-60219 A

  However, if lift pins are used to transfer the substrate to be processed between the robot arm and the susceptor, it is necessary to form a small hole for the lift pin in the susceptor. If small holes for lift pins are formed in the susceptor, the temperature distribution of the susceptor during vapor phase growth becomes non-uniform in the vicinity of the small holes, and the thickness uniformity of the formed vapor phase growth film is lost. .

  An object of the present invention is to provide a vapor phase growth apparatus that does not use lift pins and a susceptor support structure that can deliver a substrate to be processed without using lift pins, while preventing the particles in the reaction vessel from rolling up.

Means for Solving the Problems and Effects of the Invention

The vapor phase growth apparatus of the present invention is
In a vapor phase growth apparatus comprising: a susceptor having a mounting surface on which a substrate to be processed is mounted; and a reaction vessel for vapor-phase growing the substrate to be processed mounted on the mounting surface.
The susceptor has a curved surface that protrudes upward from a horizontal state where the mounting surface is horizontal or substantially horizontal. When the substrate to be processed is mounted on the convex portion of the curved surface, the outer periphery of the substrate to be processed And can be elastically deformed into a curved state in which the mounting surface is separated,
To avoid contact between the transfer robot that supports the outer peripheral portion and the susceptor during delivery of the substrate to be processed between the transfer robot and the susceptor that supports the outer peripheral portion and loads the substrate to be processed into or out of the reaction vessel. The susceptor is in a curved state, and the substrate to be processed is placed on the convex portion by the transfer robot, or the substrate to be processed placed on the convex portion is received.

  In the vapor phase growth apparatus of the present invention, when the substrate transfer robot transfers the substrate to be processed to and from the susceptor, the mounting surface of the substrate to be processed on the susceptor becomes an upwardly curved surface. When the substrate to be processed is placed on the convex portion of the curved surface, the outer peripheral portion of the substrate to be processed and the placement surface are separated from each other. Therefore, it is possible to avoid contact between the transfer robot and the susceptor when the transfer robot that supports the outer peripheral portion of the substrate to be processed transfers the susceptor and the substrate to be processed. Therefore, the transfer robot and the susceptor can directly deliver the substrate to be processed. Therefore, it is not necessary to use the adsorption of the substrate to be processed when the substrate is transferred (received) between the transfer robot and the susceptor, and it is possible to prevent the fine particles from rolling up and adhering to the substrate to be processed. Similarly, it is not necessary to use lift pins. In this specification, “separated” means physically separated.

  In addition, when the substrate to be processed is vapor-phase grown, the substrate to be processed can be vapor-phase grown by a horizontal susceptor. At this time, it is not necessary to form a small hole for the lift pin in the susceptor. Therefore, one cause (small holes for lift pins) that makes the temperature distribution of the susceptor non-uniform during vapor phase growth can be eliminated. Therefore, the temperature distribution of the susceptor during vapor phase growth can be made more uniform, and the temperature distribution of the substrate to be processed (adjacent) placed on this susceptor can be made more uniform. Therefore, the film thickness formed on the substrate to be processed during vapor phase growth can be made more uniform.

In an embodiment of the present invention,
While supporting the susceptor from below, a movable support part capable of moving the susceptor up and down,
A susceptor holding part capable of holding the outer edge part of the susceptor against the susceptor moving upward,
When the susceptor in the horizontal state moves upward by the movable support portion, the susceptor holding portion holds the outer edge portion against the susceptor moving upward, so that the susceptor can be elastically deformed from the horizontal state to the curved state.

  While the susceptor is moved upward by the movable support portion, the susceptor holding portion holds the outer edge portion of the susceptor against the susceptor moving upward. Therefore, the outer edge portion held by the susceptor holding portion tries to stop at that position, while the portions other than the outer edge portion held by the susceptor holding portion move (bias) upward. Therefore, the susceptor can be elastically deformed from the horizontal state to the curved state so that the outer edge portion held by the susceptor holding portion serves as a fulcrum.

Further, the movable support portion can fix the susceptor at a support position supporting the susceptor, and the susceptor holding portion can move the outer edge portion downward against the susceptor fixed at the support position,
When the susceptor in the horizontal state is fixed to the support position by the movable support portion, the susceptor holding portion is elastically moved from the flat state to the curved state by moving the outer edge portion downward against the susceptor fixed at the support position. It can be deformed.

  While the susceptor is fixed to the support position by the movable support portion, the outer edge portion of the susceptor is moved downward against the susceptor to which the susceptor holding portion is fixed. Therefore, the outer edge portion that is moved (biased) by the susceptor holding portion moves downward, while the portion other than the outer edge portion that is moved by the susceptor holding portion remains in the support position. Therefore, the susceptor can be elastically deformed from the horizontal state to the curved state so that the outer edge portion moved by the susceptor holding portion serves as a fulcrum.

  In the embodiment of the present invention, the susceptor can be elastically deformed from the horizontal state to the curved state by moving the movable support portion upward relative to the susceptor holding portion.

  In an embodiment of the present invention, the susceptor is made of graphite or silicon carbide coated with silicon carbide, and the movable support portion and the susceptor holding portion are made of quartz glass.

Further, the support structure of the substrate to be processed of the present invention is as follows.
A susceptor having a horizontal or substantially horizontal mounting surface for mounting a substrate to be processed;
While supporting the susceptor from below, a movable support part capable of moving the susceptor upward;
A susceptor holding part capable of holding the outer edge part of the susceptor against the susceptor moving upward,
When the susceptor is moved upward by the movable support portion, the susceptor holding portion holds the outer edge portion against the susceptor moving upward, so that the mounting surface is elastically deformed into a convex curved surface, and the substrate to be processed The substrate to be processed can be placed on the convex portion of the curved surface in a state where the outer peripheral portion and the placement surface are separated from each other.

  The substrate support structure according to the present invention includes a susceptor holding portion capable of holding the outer edge portion of the susceptor against the susceptor moved upward by the movable support portion. Therefore, when the susceptor holding portion holds the outer edge portion of the susceptor against the susceptor moving upward, the mounting surface of the susceptor is elastically deformed into a curved surface convex upward. When the substrate to be processed is placed on the convex portion of the curved surface, the outer peripheral surface of the substrate to be processed and the placement surface are separated from each other. Therefore, when the transfer robot that supports the outer peripheral portion of the substrate to be processed transfers the susceptor and the substrate to be processed, the contact between the transfer robot and the susceptor can be avoided. Therefore, the transfer robot and the susceptor can directly deliver the substrate to be processed. Therefore, the lift pins can be eliminated when the transfer robot and the susceptor deliver the substrate to be processed.

The schematic vertical cross section which shows an example of the vapor phase growth apparatus of this invention. FIG. 2 is a schematic perspective view showing the susceptor and the susceptor support structure of FIG. 1 (however, the movable mechanism is omitted). The schematic perspective view shown from the direction different from FIG. 2A. The schematic perspective view shown from the direction different from FIG. 2A and 2B. Explanatory drawing explaining the flow of a series of wafer delivery (wafer carrying-in) between a transfer robot and a susceptor (the state where the susceptor descended in preparation for wafer carrying-in). FIG. 3B is an explanatory diagram illustrating a situation in which the wafer supported by the transfer robot is positioned above the susceptor following FIG. 3A. FIG. 3B is an explanatory diagram illustrating a situation in which the susceptor that has been lowered in preparation for carrying in the wafer has risen to the vicinity of the wafer, following FIG. 3B. FIG. 3C is an explanatory diagram illustrating a situation in which the convex portion of the curved mounting surface (curved surface) and the back surface of the wafer are in contact with each other so that the susceptor (mounting surface) is convex so as to be convex upward. . FIG. 3D is an explanatory diagram illustrating a situation where the support of the wafer by the transfer robot is released and the back surface of the wafer is placed on the convex portion of the curved surface, following FIG. 3D. FIG. 3E is an explanatory diagram illustrating a situation where the curved (elastically deformed) susceptor (mounting surface) is restored and the wafer is accommodated in the counterbore portion of the susceptor, following FIG. 3E. FIG. 3F is an explanatory diagram illustrating a situation where the susceptor is lowered in preparation for the transfer robot to leave, following FIG. 3F. 3G is an explanatory diagram showing a situation where the susceptor is raised in preparation for vapor phase growth, following FIG. 3G. FIG. Explanatory drawing explaining the flow of a series of wafer delivery (wafer unloading) between a transfer robot and a susceptor (the state where the susceptor descended in preparation for wafer unloading). FIG. 4B is an explanatory diagram illustrating a situation where the transfer robot for unloading the wafer is positioned above the wafer placed on the susceptor following FIG. 4A. FIG. 4B is an explanatory diagram illustrating a situation where the susceptor that has been lowered in preparation for unloading of the wafer has risen to the vicinity of the wafer, following FIG. 4B. Continuing to FIG. 4C, the susceptor (mounting surface) is curved (elastically deformed) so as to be convex upward, and the wafer on the mounting surface is lifted by the convex portion of the curved mounting surface (curved surface). FIG. FIG. 4D is an explanatory diagram illustrating a situation where the outer peripheral portion of the wafer is supported by the transfer robot following FIG. 4D. FIG. 4E is an explanatory diagram illustrating a situation in which the curved (elastically deformed) susceptor (mounting surface) is restored to the horizontal state of the susceptor following FIG. 4E. FIG. 4F is an explanatory diagram illustrating a situation where the susceptor is lowered in preparation for unloading the wafer, following FIG. 4F. The film thickness distribution figure which shows the film thickness distribution of the epitaxial layer in the epitaxial wafer produced with the conventional vapor phase growth apparatus. The film thickness distribution figure which shows the film thickness distribution of the epitaxial layer in the epitaxial wafer produced with the vapor phase growth apparatus of this invention. The schematic horizontal sectional view which shows an example of the conventional vapor phase growth apparatus. The schematic vertical cross section which shows an example of the conventional vapor phase growth apparatus.

  FIG. 1 shows a vapor phase growth apparatus 1 used in the present invention. The vapor phase growth apparatus 1 is an apparatus for producing an epitaxial wafer by vapor phase growing an epitaxial layer on a main surface of a substrate to be processed.

  The vapor phase growth apparatus 1 includes a reaction vessel 2 that is a vapor phase growth furnace composed of a transparent quartz member, a metal member such as stainless steel, or the like. The reaction vessel 2 is hermetically configured (isolated from the atmosphere) so that impurities are not mixed into the reaction vessel 2 from the outside. Inside the reaction vessel 2 isolated from the atmospheric atmosphere, a susceptor 3 that supports a substrate to be processed (hereinafter simply referred to as a wafer W) horizontally or substantially horizontally is provided. In FIG. 1, the susceptor 3 is shown in a side view, and the wafer W is not shown hidden behind the susceptor 3.

  As shown in FIG. 2A, the susceptor 3 has a wide annular outer edge 3 a and is formed in a disc shape, and is horizontally disposed in the reaction vessel 2. On the surface of the susceptor 3, a counterbore portion 3b for placing the wafer W horizontally or substantially horizontally is formed. The counterbore part 3b is a concave part in which the upper surface of the susceptor 3 is recessed in a disk shape larger than the diameter of the wafer W, and the wafer W is disposed on the bottom surface of the counterbore part 3b. Become. The susceptor 3 is made of, for example, graphite or silicon carbide coated with silicon carbide (SiC). Therefore, the susceptor 3 can be elastically deformed according to an external force. An axis O in FIG. 1 is a central axis O that passes through the center of the disc-shaped susceptor 3 (the center of the surface of the susceptor 3 formed in a circle) and extends in the vertical direction. In addition, when the susceptor 3 is viewed from above, the outer edge portion 3a in this specification means a portion including a range from the outer edge of the susceptor 3 to the vicinity of the counterbore portion 3b (see FIG. 2A).

Returning to FIG. 1, below the susceptor 3, a susceptor support having a movable support portion 4 that supports the outer edge portion 3 a on the lower surface of the susceptor 3 and a susceptor holding portion 5 that can hold the position of the outer edge portion 3 a on the upper surface of the susceptor 3. 6 is provided. The susceptor support 6 is made of quartz glass (SiO ₂ ).

  The movable support portion 4 supports the susceptor 3 from below, and is disposed so that the susceptor 3 can be moved up and down and rotated around the central axis O. The movable support portion 4 is connected to the support shaft 4a for supporting the susceptor 3, the lower end portion of the support shaft 4a, the movable mechanism 4b for moving the support shaft 4a, and the susceptor 3 extending from the upper end portion of the support shaft 4a. A support arm portion 4c for supporting the lower surface is provided.

  The support shaft 4 a extends in a cylindrical shape from below the susceptor 3 to the vicinity of the susceptor 3 along the central axis O, and is arranged coaxially with the central axis O. A movable mechanism 4b is connected to the lower end portion of the support shaft 4a, and the support shaft 4a can be rotated around the central axis O and can be moved up and down in the central axis O direction (vertical direction) by the movable mechanism 4b.

  The movable mechanism 4b includes a rotation mechanism 7a that rotates the support shaft 4a around the central axis O, and a vertical movement mechanism 8a that moves the support shaft 4a in the vertical direction (up and down). The rotation mechanism 7a can rotate the support shaft 4a around the central axis O via a motor (not shown). The vertical movement mechanism 8a can move the support shaft 4a up and down in the direction of the central axis O (vertical direction) via a motor (not shown).

  As shown in FIGS. 2B and 2C, the upper end portion of the support shaft 4 a extends in different directions around the central axis O (see FIG. 2B) and supports a plurality of outer edge portions 3 a on the lower surface of the susceptor 3. (For example, two) supporting arm portions 4c are provided. When the susceptor 3 is viewed from above (see FIG. 2A), the support region R1 where the support arm portion 4c supports the susceptor 3 is positioned so as to sandwich the central portion of the susceptor 3. The support arm portion 4 c is fixed to the support shaft 4 a, and the support arm portion 4 c is further fixed to the outer edge portion 3 a on the lower surface of the susceptor 3. Therefore, when the support shaft 4a is rotated by the rotation mechanism 7a, the support arm portion 4c and the susceptor 3 can be rotated around the central axis O. Further, when the support shaft 4a is moved up and down by the vertical movement mechanism 8a, the support arm portion 4c and the susceptor 3 can be moved up and down in the central axis O direction (up and down direction).

  Returning to FIG. 1, the susceptor holding part 5 is connected to a holding shaft 5a that is arranged coaxially with the support shaft 4a, a lower end of the holding shaft 5a, a movable mechanism 5b that moves the holding shaft 5a, and a holding shaft 5a. A holding arm 5c extending from the upper end of the susceptor 3 to the upper surface of the susceptor 3.

  The holding shaft 5a extends in a cylindrical shape from below the susceptor 3 to the vicinity of the susceptor 3 along the center axis O so as to cover the support shaft 4a, and is disposed coaxially with the center axis O and the support shaft 4a. A movable mechanism 5b is connected to the lower end of the holding shaft 5a, and the holding shaft 5a can be rotated around the central axis O and can be moved up and down in the central axis O direction (vertical direction) by the movable mechanism 5b.

  The movable mechanism 5b includes a rotating mechanism 7b that rotates the holding shaft 5a around the central axis O, and a vertical movement mechanism 8b that moves the holding shaft 5a in the vertical direction (up and down). The rotation mechanism 7b can rotate the holding shaft 5a around the central axis O via a motor (not shown). The vertical movement mechanism 8b can move the holding shaft 5a up and down in the direction of the central axis O (vertical direction) via a motor (not shown).

  2A to 2C, the upper end portion of the holding shaft 5a is provided with a plurality of holding arm portions 5c. The holding arm 5c extends toward the outer edge of the susceptor 3 around the central axis O (see FIG. 2B), extends through the side surface of the susceptor 3 to the outer edge 3a of the upper surface of the susceptor 3, and contacts the upper surface of the outer edge 3a. To do. The plurality of holding arm portions 5c spread radially around the central axis O. When the susceptor 3 is viewed from above (see FIG. 2A), the holding arm portion 5c is positioned symmetrically about the boundary L connecting the support region R1 with the holding region R2 holding the susceptor 3. The number of the holding arm portions 5c is larger than the number of the supporting arm portions 4c, and the holding arm portions 5c are fixed to the holding shaft 5a. Therefore, when the holding shaft 5a is rotated by the rotation mechanism 7b, the holding arm portion 5c can rotate around the central axis O. Similarly, when the holding shaft 5a moves up and down by the vertical movement mechanism 8b, the holding arm 5c can move up and down in the direction of the central axis O (up and down direction).

  Returning to FIG. 1, the controller 9 is connected to the rotation mechanism 7a and the vertical movement mechanism 8a that move the support shaft 4a, and the rotation mechanism 7b and the vertical movement mechanism 8b that move the holding shaft 5a. The control unit 9 includes a CPU (not shown) and a drive circuit that drives motors provided in the mechanisms 7a, 7b, 8a, and 8b. The controller 9 (CPU and drive circuit) controls the rotation and vertical movement of the support shaft 4a and the holding shaft 5a. For example, when the support shaft 4a rotates and moves up and down, the susceptor 3 can rotate and move up and down corresponding to the support shaft 4a. When the holding shaft 5a rotates and moves up and down, the holding arm 5c can rotate and move up and down corresponding to the holding shaft 5a. By rotating or vertically moving the holding arm 5c (holding shaft 5a) corresponding to the rotation or vertical movement of the susceptor 3 (support shaft 4c), the movement of the susceptor 3 is not inhibited by the holding arm 5c.

  When the wafer W loaded into the reaction vessel 2 is transferred to the susceptor 3 or when the wafer W placed on the susceptor 3 is unloaded from the reaction vessel 2 after vapor phase growth, the susceptor 3 is moved up and down (speed, timing, amplitude). ) Is controlled by the control unit 9. Further, the rotation (rotation speed) of the susceptor 3 is controlled by the control unit 9 when the epitaxial layer is vapor-phase grown on the wafer W.

  At one end side (left side in FIG. 1) of the reaction vessel 2, the vapor growth gas G is introduced into the upper region of the susceptor 3, and the vapor growth gas G is supplied onto the main surface of the wafer W on the susceptor 3. The gas introduction pipe 10 to be connected is connected. The vapor phase growth gas G supplied into the reaction vessel 2 includes a source gas (for example, trichlorosilane), a carrier gas (for example, hydrogen) for diluting the source gas, and a dopant that imparts conductivity type to the growth layer (epitaxial layer). Contains gas. A gas discharge pipe 11 for discharging the gas in the reaction vessel 2 is connected to the opposite side of the gas introduction pipe 10 (the right side in FIG. 1).

  Around the reaction vessel 2 (for example, above and below the reaction vessel 2), a lamp L such as a halogen lamp for heating the wafer W to an epitaxial growth temperature (for example, 900 to 1200 ° C.) during vapor phase growth is provided.

  The wafer W is loaded onto the susceptor 3 in the reaction vessel 2 in the vapor phase growth apparatus 1 configured as described above, and the vapor phase growth gas G is supplied onto the susceptor 3 from the gas introduction pipe 10 to perform vapor phase growth. Is called. After the vapor phase growth is completed, the wafer W (epitaxial wafer) on the susceptor 3 is unloaded from the reaction vessel 2.

  The transfer robot 12 (see FIG. 3B) carries the wafer W including the loading of the wafer W into the reaction container 2 and the unloading of the wafer W from the reaction container 2. The transfer robot 12 can transfer the wafer W while supporting the outer periphery of the wafer W. The transfer robot 12 includes a support unit having a pair of first and second arms 13 and 14 that can be supported so as to sandwich the outer peripheral surface (side surface connecting the front surface and the back surface) of the wafer W, and the first and second arms 13. , 14 is provided with an arm moving mechanism 15 that can move independently.

  One end of the first arm 13 is connected to the arm movable mechanism 15, and a folded portion 13 a is formed that extends in the horizontal direction from one end to the other end and is lowered downward on the other end side to return to the one end side. One end of the second arm 14 is connected to the arm movable mechanism 15 so as to be positioned below the first arm 13, extends in the horizontal direction from one end to the other end, and on the other end, a tip that faces the folded portion 13 a. Part 14a is formed. The facing surfaces 13b and 14b of the folded portion 13a and the tip portion 14a serve as support surfaces for supporting the outer peripheral surface of the wafer W.

  The arm movable mechanism 15 can move the first arm 13 and the second arm 14 independently in the horizontal direction. Therefore, the arm movable mechanism 15 can change the distance D1 between the opposing surface 13b and the opposing surface 14b. For example, the distance D <b> 1 can be made longer than the diameter of the wafer W or the diameter of the wafer W. With the distance D1 longer than the diameter of the wafer W, the wafer W is positioned between the opposing surfaces 13b and 14b, and then the distance D1 is set to the diameter of the wafer W, whereby the outer peripheral surface of the wafer W can be supported. The arm movable mechanism 15 can extend and contract the first and second arms 13 and 14 independently in the horizontal direction. Therefore, when the substrate inlet for carrying the wafer W in and out of the reaction vessel 2 is released, the arms 13 and 14 are extended into the reaction vessel 2 (above the susceptor 3) by extending both arms 13 and 14. It becomes possible to put. Therefore, while maintaining the state in which the wafer W is supported by the first and second arms 13 and 14, both the arms 13 and 14 are simultaneously expanded or contracted, thereby bringing the wafer W into the reaction container 2 or from the reaction container 2. Can be carried out.

  Next, a series of flows in which the transfer robot 12 carries the wafer W into the reaction container 2 and a series of flows in which the wafer W after vapor deposition is carried out from the reaction container 2 prior to vapor phase growth will be described. In FIGS. 3A to H and FIGS. 4A to G referred to below, a part of the susceptor 3 (bore portion 3b and its periphery) is shown in a partial cross-sectional view for easy understanding of the positional relationship of the wafer W. .

  When the wafer W is carried into the reaction vessel 2, the heights of the support arm 4c and the holding arm 5c are simultaneously lowered so that the first and second arms 13 and 14 supporting the wafer W can enter. The susceptor 3 is lowered (FIG. 3A). The heights of the susceptor 3 and the holding arm portion 5c are lowered so that the upper surfaces of the susceptor 3 and the holding arm portion 5c are lower than the lower surfaces of the arms 13 and 14 that enter.

  As shown in FIG. 3B, both arms 13 and 14 are simultaneously extended while the outer peripheral surface of the wafer W is supported by the first and second arms 13 and 14, and the wafer W is moved into the reaction vessel 2 together with the arms 13 and 14. Carry in. The extension of both arms 13 and 14 is stopped at a position where the wafer W is accommodated in the counterbore 3b as viewed from above.

  After the arms 13 and 14 stop extending, the support arm 4c and the holding arm 5c are simultaneously raised so that the susceptor 3 is positioned near the lower surface of the wafer W (FIG. 3B → C). Then, with the holding arm 5c held in the vicinity of the lower surface of the wafer W, only the support arm 4c is raised. Then, the outer edge portion 3a held by the holding arm portion 5c tries to maintain its height, while the portions other than the outer edge portion 3a held by the holding arm portion 5c move upward (biasing). To do. Therefore, the susceptor 3 is curved so that the outer edge portion 3a held by the holding arm portion 5c serves as a fulcrum. Therefore, the susceptor 3 is elastically deformed from a horizontal state in which the mounting surface (bottom surface of the counterbore 3b) on which the wafer W is mounted is horizontal or substantially horizontal to a curved state in which the mounting surface is a convex curved surface. (FIG. 3C → D). As shown in FIG. 2A, when the susceptor 3 is viewed from above, the holding region R2 is line-symmetrically centered on the boundary L connecting the support regions R1, so the susceptor 3 is curved in a mountain-fold shape so as to have a mountain-fold shape. The peak portion becomes the convex portion C.

  As shown in FIG. 3D, the convex portion C of the curved susceptor 3 is located at a close distance so as to contact or substantially contact the back surface of the wafer W. Then, the support of the wafer W by the first and second arms 13 and 14 is released, and the wafer W is placed on the convex portion C of the susceptor 3 (FIG. 3D → E). In other words, the wafer W is placed on the peak portion of the mountain-shaped susceptor 3. In a state where the wafer W is placed on the convex portion C of the curved surface, the outer peripheral portion of the wafer W and the placement surface of the wafer W (the bottom surface of the counterbored portion 3b) are separated from each other.

  Next, the holding arm 5c is left as it is, and only the support arm 4c is lowered. Then, the urging force that curved the susceptor 3 is gradually released, and the susceptor 3 is restored from the curved state to the horizontal state. Therefore, the wafer W placed on the convex portion C of the curved surface gradually descends as the susceptor 3 is released from the curvature, and the wafer W is accommodated in the counterbore portion 3b when the susceptor 3 is restored to the horizontal state. (FIG. 3E → F). Thereafter, when the first and second arms 13 and 14 on which the wafer W is placed on the susceptor 3 exits the reaction vessel 2, the support arm 4c and the holding arm 5c are prevented from coming into contact with the susceptor 3 and the holding arm 5c. Are simultaneously lowered to lower the susceptor 3 (FIG. 3G). After the lowering, the first and second arms 13 and 14 are contracted, and both arms 13 and 14 are retracted from the reaction vessel 2.

  Thereafter, the horizontal susceptor 3 is raised to the height for epitaxial growth by the support arm portion 4c and the holding arm portion 5c (FIG. 3H), and epitaxial growth is performed on the wafer W. During epitaxial growth, the support arm 4c and the holding arm 5c are simultaneously rotated around the central axis O (see FIG. 1) to rotate the susceptor 3 and introduce the vapor growth gas G from the gas introduction pipe 10. An epitaxial layer is grown on the wafer W.

  When the epitaxial growth is completed, the wafer W is unloaded from the reaction vessel 2 to the outside. When the wafer W is unloaded, the process is the reverse of the case where the wafer W is loaded into the reaction container 2. The susceptor 3 at the time of vapor phase growth is positioned at a height that inhibits the entry of the first and second arms 13 and 14 entering the reaction vessel 2. Therefore, first, the susceptor 3 is lowered by simultaneously lowering the support arm portion 4c and the holding arm portion 5c so that the first and second arms 13 and 14 can enter (FIG. 4A). The first and second arms 13 and 14 are simultaneously extended into the space formed by the lowering of the support arm portion 4 c and the holding arm portion 5 c, and both arms 13 and 14 enter the reaction vessel 2. Then, the distance D1 between the facing surface 13b and the facing surface 14b is made longer than the diameter of the wafer W, and the first and second arms 13 and 14 are stopped at a position where the diameter of the wafer W is within the distance D1 ( FIG. 4B).

  Next, the support arm portion 4c and the holding arm portion 5c are simultaneously raised until the susceptor 3 is positioned in the vicinity of the lower surface of the wafer W (FIG. 4B → C). Then, while holding the holding arm portion 5c in the vicinity of the lower surface of the wafer W, only the supporting arm portion 4c is raised, and the susceptor 3 is elastically deformed from the horizontal state to the curved state (FIG. 4C → D).

  The wafer W placed on the counterbore portion 3b is curved at the susceptor 3 and the outer periphery of the wafer W and the placement surface (bottom surface of the counterbore portion 3b) are gradually separated from each other. To rise. The wafer W finally rises to a position that fits between the opposing surfaces 13b and 14b, and in this state, the wafer W is placed on the convex portion C of the curved surface (FIG. 4D).

  Then, the first and second arms 13 and 14 are moved and supported so that the outer peripheral portion of the wafer W is sandwiched between the opposing surfaces 13b and 14b (FIG. 4D → E). After the wafer W is supported by the first and second arms 13 and 14, the holding arm portion 5c is left as it is, and only the support arm portion 4c is lowered. Then, the urging force that curved the susceptor 3 is gradually released, and the susceptor 3 is restored from the curved state to the horizontal state (FIG. 4E → F). Thereafter, the support arm portion 4c and the holding arm portion 5c are simultaneously lowered so that the first and second arms 13, 14 supporting the wafer W do not come into contact with the susceptor 3 and the holding arm portion 5c when leaving the reaction vessel 2. As a result, the susceptor 3 is lowered (FIG. 4F → G). After the lowering, the first and second arms 13 and 14 are contracted while the wafer W is supported, the both arms 13 and 14 are retracted from the reaction container 2, and the wafer W is unloaded from the reaction container 2.

  In the present embodiment, when the transfer robot 12 transfers the wafer W to and from the susceptor 3, the placement surface of the susceptor 3 (the bottom surface of the counterbore portion 3b) is a curved surface that is convex upward. When the wafer W is placed on the convex portion C of the curved surface, the outer peripheral portion of the wafer W and the placement surface are separated from each other. Therefore, it is possible to avoid contact between the transfer robot 12 and the susceptor 3 when the transfer robot 12 supporting the outer periphery of the wafer W by the first and second arms 13 and 14 receives the susceptor 3 and the wafer W. Therefore, the transfer robot 12 and the susceptor 3 can directly deliver the wafer W. Therefore, it is not necessary to adsorb the wafer W when the wafer W is transferred (received) between the transfer robot 12 and the susceptor 3, and it is possible to prevent fine particles from rolling up and adhering to the wafer W due to the adsorption. Similarly, it is not necessary to use lift pins.

  Further, during the vapor phase growth, the wafer W can be mounted on the horizontal susceptor 3 to perform the vapor phase growth. At this time, it is not necessary to form a small hole for the lift pin in the susceptor 3. Therefore, one cause (small holes for lift pins) that makes the temperature distribution of the susceptor 3 uneven during vapor phase growth can be eliminated. Therefore, the temperature distribution of the susceptor 3 during vapor phase growth can be made more uniform, and the temperature distribution of the wafer W placed on the susceptor 3 can be made more uniform. Therefore, the film thickness formed on the wafer W during vapor phase growth can be made more uniform.

  EXAMPLES Hereinafter, although an Example and a prior art example are shown and this invention is demonstrated concretely, this invention is not limited to these.

(Example)
As an example, an epitaxial wafer was manufactured using the susceptor 3 and the susceptor support 6 shown in FIG. The susceptor 3 was made of silicon carbide having a thickness of 2 mm and a diameter of 373 mm, and a counterbore portion 3 b having a depth of 0.76 mm and a diameter of 303 mm for accommodating the substrate was provided on the surface of the susceptor 3. As a production condition of the epitaxial wafer, a 300 mm silicon single crystal substrate was prepared. Then, the prepared silicon single crystal substrate was placed on the susceptor 3 to form an epitaxial layer on the silicon single crystal substrate.

(Conventional example)
As a conventional example, a susceptor having three small holes for lift pins provided at equal angular intervals around the central axis O of the susceptor 3 is used, and an epitaxial wafer is manufactured under the same conditions as in the embodiment except for the susceptor 3 and the susceptor support 6. It was. When the silicon single crystal substrate was placed on the susceptor and received from the susceptor, lift pins were used.

  When lift pins are used in FIG. 5A, the film thickness distribution of the epitaxial layer when susceptor 3 is used is shown in FIG. 5B. When lift pins were used as shown in FIG. 5A, three locations where the thickness of the epitaxial layer was reduced corresponding to the positions of the small holes for the lift pins were generated. The three locations where the film thickness was reduced coincided with the locations where there were small holes for lift pins. On the other hand, as shown in FIG. 5B, when the susceptor 3 of the present invention was used, no film thickness distribution such as local film thickness reduction was observed.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  In the above embodiment, when the susceptor 3 in the horizontal state moves upward by the support arm portion 4c, the holding arm portion 5c holds the outer edge portion 3a of the susceptor 3 against the susceptor 3 moving upward. An example of bending is shown. In addition to this, the susceptor 3 may be bent by the following method. For example, the susceptor 3 is fixed at a support position supported by the support arm portion 4c, and the outer edge portion 3a of the susceptor 3 is moved downward against the susceptor 3 to which the holding arm portion 5c is fixed. The susceptor 3 may be curved. In the above description, the susceptor 3 curved in a mountain fold shape is illustrated, but the susceptor 3 may be curved in various curved states other than the mountain fold shape, such as bending so that only the central portion of the susceptor 3 protrudes.

  Further, the transfer robot 12 that supports the outer peripheral surface of the wafer W so as to be sandwiched between the opposing surfaces 13b and 14b is illustrated. As the transfer robot, a robot that supports the outer edge of the lower surface of the wafer W and transfers the wafer W can also be used. The transfer robot may be any robot that can transfer the wafer W while supporting the outer peripheral portion of the wafer W. Therefore, the wafer W placed on the curved susceptor 3 does not need to be separated from the placement surface over the entire outer peripheral portion of the wafer W. It is only necessary that a part of the outer peripheral portion of the wafer W is separated from the mounting surface so that the transfer robot can support the wafer W.

DESCRIPTION OF SYMBOLS 1 Vapor growth apparatus 2 Reaction container 3 Susceptor 3a Outer edge part 3b Counterbore part 4 Movable support part 4a Support shaft 4b Movable mechanism 4c Support arm part 5 Susceptor holding part 5a Holding shaft 5b Movable mechanism 5c Holding arm part 12 Transfer robot 13 1st Arm 14 Second arm W Wafer

Claims (7)

In a vapor phase growth apparatus comprising: a susceptor having a mounting surface on which a substrate to be processed is mounted; and a reaction vessel that vapor-phase grows the substrate to be processed mounted on the mounting surface.
In the susceptor, when the placement surface is horizontal or substantially horizontal, the placement surface becomes a curved surface convex upward, and the substrate to be processed is placed on the convex portion of the curved surface. It can be elastically deformed into a curved state in which the outer peripheral portion of the substrate to be processed and the placement surface are separated from each other,
The transfer robot that supports the outer peripheral portion and supports the outer peripheral portion when the substrate to be processed is transferred to and from the susceptor by a transfer robot that carries the substrate to be processed into or out of the reaction vessel. In order to avoid contact between the susceptor and the susceptor, the susceptor is in the curved state, and the transfer robot is caused to place the substrate to be processed on the convex portion or to receive the substrate to be processed placed on the convex portion. A vapor phase growth apparatus characterized by that.   The vapor phase growth apparatus according to claim 1, wherein during the vapor phase growth of the substrate to be processed, the substrate to be processed is vapor phase grown by the horizontal susceptor. While supporting the susceptor from below, a movable support portion capable of moving the susceptor up and down;
A susceptor holding part capable of holding an outer edge part of the susceptor against the susceptor moving upward,
When the susceptor in the horizontal state is moved upward by the movable support portion, the susceptor holding portion holds the outer edge portion against the susceptor moving upward, whereby the susceptor is bent from the horizontal state. The vapor phase growth apparatus according to claim 1 or 2, which is elastically deformed to a state. The movable support portion can fix the susceptor at a support position supporting the susceptor, and the susceptor holding portion can move the outer edge portion downward against the susceptor fixed at the support position. Yes,
When the susceptor in the horizontal state is fixed to the support position by the movable support part, the susceptor holding part moves the outer edge part downward against the susceptor fixed to the support position. The vapor phase growth apparatus according to claim 3, wherein the susceptor is elastically deformed from the horizontal state to the curved state.   5. The vapor phase growth apparatus according to claim 4, wherein the susceptor is elastically deformed from the horizontal state to the curved state by moving the movable support portion relatively upward with respect to the susceptor holding portion.   The vapor phase growth apparatus according to any one of claims 3 to 5, wherein the susceptor is made of graphite or silicon carbide coated with silicon carbide, and the movable support portion and the susceptor holding portion are made of quartz glass. A susceptor having a horizontal or substantially horizontal mounting surface for mounting a substrate to be processed;
While supporting the susceptor from below, a movable support part capable of moving the susceptor upward;
A susceptor holding part capable of holding an outer edge part of the susceptor against the susceptor moving upward,
When the susceptor is moved upward by the movable support portion, the susceptor holding portion holds the outer edge portion against the susceptor moving upward, so that the placement surface is elastic to a curved surface convex upward. A support structure for a substrate to be processed, wherein the substrate to be processed can be placed on the convex portion of the curved surface in a state where the outer peripheral portion of the substrate to be processed and the placement surface are separated from each other.