JP2018022724A - Susceptor support shaft and epitaxial growth equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a susceptor support shaft capable of manufacturing an epitaxial wafer with suppressed Light Point Defect (LPD) by suppressing sliding dusts originated from by-products generated during epitaxial growth and sliding dusts generated when adjusting the transporting operation of a semiconductor wafer, and also with high flatness.SOLUTION: In a susceptor support shaft 100 for an epitaxial growth equipment, an inner wall of a through-hole 40 of an arm has a first inner wall 42 that defines a cylindrical first space, a second inner wall 44 that defines a reverse tapered second space, and a third inner wall 46 that defines a tapered third space. The second inner wall and the third inner wall have portions inclined with respect to a central axis X of the cylindrical shape.SELECTED DRAWING: Figure 4A

Description

  The present invention relates to a susceptor support shaft that supports a susceptor from below in an epitaxial growth apparatus, and an epitaxial growth apparatus having the susceptor support shaft.

  An epitaxial wafer is obtained by vapor-phase-growing an epitaxial film on the surface of a semiconductor wafer. For example, when crystal integrity is more required or a multilayer structure with different resistivity is required, an epitaxial silicon wafer is produced by vapor-phase growth (epitaxial growth) of a single crystal silicon thin film on a silicon wafer. To do.

  For manufacturing an epitaxial wafer, for example, a single wafer epitaxial growth apparatus is used. Here, a general single wafer epitaxial growth apparatus will be described with reference to FIG. As shown in FIG. 9, the epitaxial growth apparatus 2000 has a process chamber 102 including an upper dome 104, a lower dome 106, and a dome mounting body 108, and the process chamber 102 defines an epitaxial film forming chamber. The process chamber 102 is provided with a gas supply port 112 and a gas discharge port 114 for supplying and discharging the reaction gas at positions opposite to the side surfaces thereof. On the other hand, a susceptor 120 on which the semiconductor wafer W is placed is disposed in the process chamber 102. The susceptor 120 is supported by the susceptor support shaft 500 from below. The susceptor support shaft 500 includes a main column 10 and three arms 30 (one is not shown) extending radially from the main column 10 at equal intervals. One is not shown) and supports the outer periphery of the lower surface of the susceptor 120. In addition, three through holes (one not shown) are formed in the susceptor 120, and one through hole is also formed in each of the three arms 30. Lift pins 130 are inserted into the through holes of the arms 30 and the through holes of the susceptor 120. A lower end portion 136 of the lift pin is supported by the lifting shaft 140. When supporting the semiconductor wafer W carried into the process chamber 102, placing the semiconductor wafer W on the susceptor 120, and carrying out the epitaxial wafer after vapor phase growth out of the process chamber 102, the semiconductor wafer W is moved up and down. As the shaft 140 moves up and down, the lift pin 130 moves up and down while sliding with the through hole of the arm 30 and the through hole of the susceptor 120, and the semiconductor wafer W is moved up and down at its upper end 132.

  In Patent Document 1, in such a single-wafer epitaxial growth apparatus, when a semiconductor wafer exists on the lift pins, wobbling occurs due to the load of the semiconductor wafer, and the wobbling causes the semiconductor wafer to be placed on the susceptor. Therefore, by connecting a plurality of lift pins with an auxiliary member, wobbling of the lift pins when raising and lowering the semiconductor wafer is suppressed compared to the case without the auxiliary member, and the mounting position of the semiconductor wafer is reduced. A technique for reducing the deviation is described.

JP 2014-220427 A

  In general, the materials of the susceptor, lift pins, and susceptor support shaft constituting the epitaxial growth apparatus are limited from the viewpoint of heat resistance, cost, and function. For example, when quartz is used for the susceptor support shaft, a member obtained by coating a carbon graphite base material with silicon carbide is generally used for the susceptor and the lift pin. At this time, since the thermal expansion coefficient of carbon graphite or silicon carbide is larger than the thermal expansion coefficient of quartz, three states occur in the epitaxial growth apparatus depending on the temperature in the epitaxial growth apparatus. That is, at room temperature for adjusting the lift pins and adjusting the semiconductor wafer transfer operation described later, a temperature range of 600 ° C. to 900 ° C. for transferring the semiconductor wafer, and a temperature range of 1100 ° C. to 1200 ° C. for epitaxial growth. The positional relationship among the susceptor support shaft, the susceptor, and the lift pin is different.

  Here, in order to obtain an epitaxial wafer having high flatness by making the film thickness of the epitaxial film uniform, during the transfer operation of the semiconductor wafer W in the temperature range of 600 ° C. or higher and 900 ° C. or lower, It is important to keep the surface parallel to the horizontal plane. Therefore, generally, as shown in FIG. 10B, in the temperature range of 600 ° C. or more and 900 ° C. or less, the dimension of each member is set so that the central axis of each lift pin 130 is parallel to the vertical direction. Designed. However, when the dimensions of each member are designed based on a temperature range of 600 ° C. or more and 900 ° C. or less, each lift pin 130 is at room temperature as shown in FIG. 10A due to the difference in thermal expansion coefficient. Is inclined inward in the radial direction of the susceptor 120. On the other hand, in the temperature range of 1100 ° C. or more and 1200 ° C. or less, the center axis of each lift pin 130 is inclined outward in the radial direction of the susceptor 120 as shown in FIG.

  Here, in the process of epitaxial growth, a source gas such as trichlorosilane gas, a dopant gas such as diborane gas, and a carrier gas such as hydrogen gas are supplied in a temperature range from 1100 ° C. to 1200 ° C. Epitaxial film is grown. At this time, the gas fills the process chamber 102 and goes around to a place other than the surface of the semiconductor wafer W, so that a by-product containing the gas as a main component adheres to each member in the process chamber 102. . Among them, in particular, the lift pin member is a member obtained by coating a carbon graphite substrate with silicon carbide. Therefore, as shown in FIG. 10C, the periphery of the open end of the through hole 40 of each arm, that is, each lift pin Other members in the process chamber 102 may have a region sandwiched between the side surface of the straight body portion 134 and the upper surface 32A of each arm or a region sandwiched between the side surface of the straight body portion 134 of each lift pin and the lower surface 32B of each arm. Compared to the by-product, the by-product tends to adhere. Furthermore, this phenomenon becomes more prominent as the epitaxial growth temperature is higher and the epitaxial film is thicker.

  On the other hand, in the case of using an epitaxial growth apparatus using a conventional susceptor support shaft, after all the epitaxial wafer manufacturing steps are completed, the inside of the process chamber 102 is etched with hydrogen chloride gas or the like, whereby the above-mentioned by-product is obtained. Was removed. However, the transfer operation of the epitaxial wafer in the temperature range of 600 ° C. or higher and 900 ° C. or lower is performed immediately after the epitaxial growth. That is, as will be described in detail later, as shown in FIG. 10B, each lift pin 130 is connected to each through-hole 122 and each of the susceptor in a state where by-products are attached around the open end of the through-hole 40 of each arm. The epitaxial wafer moves to a predetermined position by sliding with the arm through hole 40. Thereafter, the epitaxial wafer is carried out of the process chamber 102 by the transfer blade. During the sliding, stress associated with the contact between the side surface of the straight body portion 134 of each lift pin and the by-product is concentrated around the open end of the through hole 40 of each arm. Things peel off. Then, the peeled by-product scatters in the process chamber 102 and adheres to the surface of the epitaxial wafer, thereby causing a sliding dust problem that LPD (Light Point Defect) occurs on the surface of the epitaxial wafer. Moreover, when stress concentrates as mentioned above, it is prevented that each lift pin 130 raises / lowers smoothly up and down. Thereby, the repeat accuracy of the conveyance operation of the semiconductor wafer W is lowered, and there is a problem that the flatness of the epitaxial wafer is lowered.

  As will be described in detail later, each lift pin 130 is connected to each through-hole 122 of each susceptor and each through-hole 40 of each arm when attaching each lift pin 130 at normal temperature or adjusting the transfer operation of the semiconductor wafer W. A step of moving up and down while sliding is included. At this time, as shown in FIG. 10A, when each lift pin 130 is moved up and down in a state where the central axis of each lift pin 130 is inclined inward in the radial direction of the susceptor 120, the opening of the through hole 40 of each arm is opened. The lift pin 130 and the arm 30 rub against each other around the end. As a result, the lift pins 130 and the arm 30 are worn, and sliding dust is generated. Further, when the lift pin 130 and the arm 30 are rubbed, sliding resistance is generated. Thereby, the precision of the conveyance confirmation of the semiconductor wafer W falls, and the problem that the flatness of an epitaxial wafer falls also arises.

  Moreover, in patent document 1, the several lift pin is mutually connected by the auxiliary member from a viewpoint of suppressing the wobble of a lift pin. However, regarding the design of each member constituting the epitaxial growth apparatus, no consideration is given to the difference in thermal expansion coefficient between the members at room temperature, a temperature range of 600 ° C. to 900 ° C., and a temperature range of 1100 ° C. to 1200 ° C. . On the contrary, it is not even recognized that by-products generated due to epitaxial growth cause LPD on the surface of the epitaxial wafer and adversely affect the flatness of the epitaxial wafer.

  Therefore, in view of the above problems, the present invention suppresses the generation of sliding dust caused by by-products generated during epitaxial growth and sliding dust generation during adjustment of the semiconductor wafer transport operation, thereby suppressing LPD. It is another object of the present invention to provide a susceptor support shaft and an epitaxial growth apparatus that can manufacture an epitaxial wafer having high flatness.

The gist configuration of the present invention for solving the above-described problems is as follows.
(1) A susceptor support shaft for supporting the susceptor from below in an epitaxial growth apparatus for vapor-phase growing an epitaxial film on the surface of a semiconductor wafer placed on the susceptor,
A main pillar disposed substantially coaxially with the center of the susceptor;
Three or more arms extending radially from the main pillar to the lower periphery of the susceptor;
A support pin that is provided at each end of the arm and directly supports the susceptor;
The arm is provided with a through-hole penetrating the arm from its upper surface toward its lower surface,
The inner wall of the through hole is
A first inner wall defining a cylindrical first space having a central axis parallel to the axis of the main pillar;
A second inner wall extending from an upper end of the first inner wall to an opening end of the upper surface of the arm, and defining a second space communicating with the first space;
A third inner wall that extends from the lower end of the first inner wall to the opening end of the lower surface of the arm and defines a third space that communicates with the first space;
Have
When viewed in the central axis direction of the cylindrical shape, the open end of the upper surface of the arm and the open end of the lower surface of the arm surround the upper end and the lower end of the first inner wall,
The second inner wall and the third inner wall are straight in all cross sections passing through the cylindrical central axis,
In a cross section passing through the central axis of the cylindrical shape and parallel to the extending direction of the arm, a straight line on the support pin side of the second inner wall and a straight line on the main column side of the third inner wall are the cylinder. And / or the straight line on the main column side of the second inner wall and the straight line on the support pin side of the third inner wall are inclined with respect to the central axis of the cylinder. A susceptor support shaft characterized by being inclined.

(2) In a cross section passing through the central axis of the cylindrical shape and parallel to the extending direction of the arm, angles defined as follows are D <45 °, E <45 °, F <45 °, and G < The susceptor support shaft according to (1), which satisfies 45 °.
D: Angle formed by a straight line on the support pin side of the second inner wall and the central axis of the cylindrical shape E: Angle F formed by a straight line on the main column side of the second inner wall and the central axis of the cylindrical shape : Angle G formed by the straight line on the main pillar side of the third inner wall and the central axis of the cylindrical shape: Angle formed by the straight line on the support pin side of the third inner wall and the central axis of the cylindrical shape

  (3) The susceptor support shaft according to (2), wherein 0 ° <D <45 °, 0 ° <E <45 °, 0 ° <F <45 °, and 0 ° <G <45 ° are satisfied.

  (4) The susceptor support shaft according to (2), wherein 0 ° <D <45 °, E = 0 °, 0 ° <F <45 °, and G = 0 °.

  (5) The susceptor support shaft according to (2), wherein D = 0 °, 0 ° <E <45 °, F = 0 °, and 0 ° <G <45 °.

  (6) The susceptor support shaft according to any one of (2) to (5), wherein 0 ° <D + E <45 °.

  (7) The susceptor support shaft according to any one of (2) to (6), wherein 0 ° <F + G <45 °.

  (8) The susceptor support shaft according to any one of (2) to (7), wherein D = F and / or E = G.

  (9) The susceptor support shaft according to any one of (1) to (8), wherein a height C of the first space is 8.00 mm to 14.00 mm.

  (10) The thickness of the arm is any one of the above (1) to (9), which is thicker than other portions only in the peripheral portion of the through hole along the extending direction. Susceptor support shaft.

  (11) The susceptor support shaft according to (10), wherein a thickness of the arm around the through hole is 11.00 mm or more and 20.00 mm or less.

(12) An epitaxial growth apparatus for vapor-phase growing an epitaxial film on the surface of a semiconductor wafer,
A process chamber;
A susceptor for mounting the semiconductor wafer in the process chamber;
The susceptor support shaft according to any one of (1) to (11), which supports the susceptor from below;
Three or more lift pins that are inserted into the respective through holes of the three or more arms and are moved up and down in a vertical direction to attach and detach the semiconductor wafer to and from the susceptor;
An epitaxial growth apparatus comprising:

  According to the susceptor support shaft and the epitaxial growth apparatus of the present invention, LPD is suppressed by suppressing the generation of sliding dust caused by by-products generated during epitaxial growth and sliding dust generation during adjustment of the semiconductor wafer transfer operation. An epitaxial wafer which is suppressed and has high flatness can be manufactured.

It is a schematic diagram of the epitaxial growth apparatus 1000 by one Embodiment of this invention in the temperature range of 600 degreeC or more and 900 degrees C or less. It is a schematic diagram of the epitaxial growth apparatus 1000 by one Embodiment of this invention in the temperature range of 1100 degreeC or more and 1200 degrees C or less. It is a schematic diagram of the epitaxial growth apparatus 1000 by one Embodiment of this invention explaining the process of conveying the semiconductor wafer W to the process chamber 102 under normal temperature. (A) is an exploded perspective view of the susceptor 120, and (B) is an exploded perspective view of the susceptor support shaft 100. 4A is an exploded perspective view of the lift pin 130, and FIG. 1 is a partial perspective view of a susceptor support shaft 100 according to a first embodiment of the present invention. It is the figure which looked at the susceptor support shaft 100 by 1st embodiment of this invention from the upper direction of the cylindrical central axis X. FIG. FIG. 3 is a partial cross-sectional view of the susceptor support shaft 100 according to the first embodiment of the present invention in a cross section passing through a cylindrical central axis X and parallel to the extending direction of the arm. It is the figure which looked at the susceptor support shaft 100 by 1st embodiment of this invention from the downward direction of the cylindrical central axis X. FIG. 1 is a cross-sectional view of a susceptor support shaft 100 according to a first embodiment of the present invention that passes through a cylindrical central axis X and is perpendicular to an extending direction of an arm. (A) is a schematic diagram showing the positional relationship between the susceptor support shaft 100 and the lift pins 130 according to the first embodiment of the present invention in a temperature range of 1100 ° C. or more and 1200 ° C. or less, and (B) is a room temperature. It is a fragmentary perspective view of the susceptor support shaft 200 by 2nd embodiment of this invention. It is the figure which looked at the susceptor support shaft 200 by 2nd embodiment of this invention from the upper direction of the cylindrical central axis X. FIG. It is a fragmentary sectional view in the section which passes along cylindrical central axis X and is parallel to the extension direction of an arm of susceptor support shaft 200 by a second embodiment of the present invention. It is the figure which looked at the susceptor support shaft 200 by 2nd embodiment of this invention from the downward direction of the cylindrical central axis X. FIG. FIG. 6 is a partial perspective view of a susceptor support shaft 300 according to a third embodiment of the present invention. It is the figure which looked at the susceptor support shaft 300 by 3rd embodiment of this invention from the upper direction of the cylindrical central axis X. FIG. FIG. 10 is a partial cross-sectional view of a susceptor support shaft 300 according to a third embodiment of the present invention in a cross section passing through a cylindrical central axis X and parallel to an extending direction of an arm. It is the figure which looked at the susceptor support shaft 300 by 3rd embodiment of this invention from the downward direction of the cylindrical central axis X. FIG. FIG. 6 is a partial cross-sectional view of a susceptor support shaft 400 according to another embodiment of the present invention in a cross section passing through a cylindrical central axis X and parallel to an extending direction of an arm. It is a schematic diagram of a conventional epitaxial growth apparatus 2000. (A) is at room temperature, (B) is in the temperature range of 600 ° C. or higher and 900 ° C. or lower, and (C) is in the temperature range of 1100 ° C. or higher and 1200 ° C. or lower, the susceptor 120, susceptor support shaft 500 of the conventional epitaxial growth apparatus 2000, FIG. 5 is a schematic diagram showing a positional relationship between lift pins 130 and a lifting shaft 140.

  An epitaxial growth apparatus 1000 according to an embodiment of the present invention will be described with reference to FIGS. 2A, 2B and 3A, 3B, the susceptor 120, the susceptor support shaft 100, the lift pin 130, and the elevating shaft 140 included in the epitaxial growth apparatus 1000 will be described. . Furthermore, with reference to FIGS. 4-8, the through-hole 40 provided in each arm 30 which comprises the susceptor support shaft 100,200,300,400 which is the characteristic part of this invention is demonstrated.

(Epitaxial growth equipment)
An epitaxial growth apparatus 1000 shown in FIG. 1A shows a process chamber 102, a susceptor 120 also shown in FIG. 2A, a susceptor support shaft 100 also shown in FIG. 2B, and FIG. It has three lift pins 130 and a lifting shaft 140 shown in FIG.

(Process chamber)
Referring to FIG. 1A, a process chamber 102 includes an upper dome 104, a lower dome 106, and a dome mounting body 108, and the process chamber 102 defines an epitaxial film forming chamber. The process chamber 102 is provided with a gas supply port 112 and a gas discharge port 114 for supplying and discharging reaction gas at positions opposite to the side surfaces thereof.

(Susceptor)
The susceptor 120 is a disk-shaped member on which the semiconductor wafer W is placed inside the process chamber 102. Here, of the main surfaces of the susceptor 120, the main surface on the side where the semiconductor wafer W is placed is the front surface of the susceptor 120, and the main surface opposite to the main surface is the back surface of the susceptor 120. 2A, the susceptor 120 has three through holes 122 that penetrate the susceptor from the front surface to the back surface of the susceptor 120 at equal intervals of 120 ° in the circumferential direction. The lift pins 130 described later are inserted through the through holes 122 of these susceptors. Each through-hole 122 of the susceptor is concentrically positioned in a back surface region having a radius of 50% or more of the semiconductor wafer W. The susceptor 120 may be made of carbon graphite (graphite) as a base material and the surface thereof coated with silicon carbide (SiC: Vickers hardness 2,346 kgf / mm ² ). On the front surface of the susceptor 120, a counterbore part (not shown) for accommodating and placing the semiconductor wafer W is formed.

(Susceptor support shaft)
The susceptor support shaft 100 supports the susceptor 120 from below in the process chamber 102. As shown in FIG. 2B, the main pillar 10, the three arms 30, and the three support pins 20 are provided. And have. The main column 10 is disposed substantially coaxially with the center of the susceptor 120.

Referring to FIG. 2B, the three arms 30 extend radially from the main pillar 10 below the peripheral edge of the susceptor 120. Each arm 30 has a rectangular cross-sectional shape perpendicular to its extending direction. Here, of the four surfaces of the arm 30, the surface on the susceptor 120 side is the upper surface 32A of the arm, and the opposite surface is the lower surface 32B of the arm. Each arm 30 has an arm through hole 40 penetrating the arm 30 from the upper surface 32A to the lower surface 32B of the arm. The lift pins 130 described later are inserted into the through holes 40 of these arms, respectively. In the present specification, the “periphery of the susceptor” means a region that is 80% or more outside the susceptor radius from the susceptor center. Each support pin 20 directly supports the susceptor 120 at the tip of each arm 30. That is, each support pin 20 supports the rear surface peripheral edge portion of the susceptor 120. The susceptor support shaft 100 is preferably made of quartz (Vickers hardness 1,103 kgf / mm ² ), and more preferably made of synthetic quartz. However, the tip portion of each support pin 20 is preferably made of the same silicon carbide as susceptor 120.

  The characteristic part of the present invention is the shape of the arm through hole 40 provided in each arm 30 constituting the susceptor support shaft 100, and the technical significance thereof will be described later.

(Lift pin)
As shown in FIG. 3A, each lift pin 130 includes a straight body portion 134 inserted through each through hole 122 of the susceptor and the through hole 40 of each arm, and each through portion of the straight body portion 134 and the susceptor 120. Each of the upper end portion 132 and the lower end portion 136 has a diameter larger than that of the hole 122. The lift pins 130 are inserted into the through holes 122 of the susceptor and the through holes 40 of the arms, respectively. Each lift pin 130 is moved up and down by a lifting shaft 140 described later, thereby supporting the semiconductor wafer W on the susceptor 120 while supporting the semiconductor wafer W (back surface region having a radius of 50% or more) at each upper end portion 132. Can be attached and detached. Details of this operation will be described later. As with the susceptor 120, each lift pin 130 is generally formed by coating a carbon graphite substrate with silicon carbide.

(Elevating shaft)
As shown in FIG. 3 (B), the elevating shaft 140 defines a hollow that accommodates the main column 10 of the susceptor support shaft 100, and a main column 142 of the elevating shaft that shares the rotation axis with the main column 10, and this The three columns 144 branch off at the tips of the main pillars 142 of the lifting shaft, and the lower ends 136 of the lift pins 130 are supported by the tips of the posts 144, respectively. The lifting shaft 140 is preferably made of quartz. When the elevating shaft 140 moves up and down along the main pillar 10 of the susceptor support shaft 100, each lift pin 130 can be raised and lowered.

(Heating lamp)
The heating lamp 110 is disposed in the upper region and the lower region of the process chamber 102, and generally, a halogen lamp or an infrared lamp having a high temperature rising / falling speed and excellent temperature controllability is used.

(Upper and lower pyrometers)
An upper pyrometer 116 a and a lower pyrometer 116 b are arranged in the upper region and the lower region of the process chamber 102, and the upper pyrometer 116 a detects the temperature of the surface to be processed of the semiconductor wafer W. The lower pyrometer 116 b Detect the backside temperature. Based on the detection values of both pyrometers, the output of the heating lamp 110 is adjusted so as to correct the temperature difference from the target temperature set value by a power output control means (not shown). Further, the positional relationship between the lower pyrometer 116b and the susceptor support shaft 100 is a positional relationship in which the arm 30 passes between the lower pyrometer 116b and the back surface of the susceptor 120 as the susceptor support shaft 100 rotates. Yes.

(Transfer chamber)
Referring to FIGS. 1B and 1C, transfer chamber 103 is disposed adjacent to process chamber 102. Although details will be described later, when the semiconductor wafer W is transported, the process chamber 102 and the transfer chamber 103 communicate with each other by opening the on-off valve 119. Further, as shown in FIG. 1B, the process chamber 102 and the transfer chamber 103 are isolated by closing the on-off valve 119 during epitaxial growth.

(Transport robot, transfer arm, and transfer blade)
Referring to FIG. 1C, the transfer robot 118a is disposed in the transfer chamber 103 and controls the transfer operation of the semiconductor wafer W. A transfer arm 118b is connected to the transfer robot 118a. Further, a transfer blade 118c for temporarily placing the semiconductor wafer W is connected to the tip of the transfer arm 118b. Here, the transfer robot 118a generally has a cylindrical structure. When the transfer robot 118a rotates around the cylindrical axis, the transfer arm 118b connected to the transfer robot 118a can rotate in a horizontal plane. Further, the transfer arm 118b can be expanded and contracted in the horizontal direction. Note that the rotation and expansion / contraction operations are controlled by a stepping motor (not shown) that forms part of the transport robot 118a. Specifically, the number of operation steps related to the rotation and expansion / contraction of the stepping motor is appropriately adjusted. It is controlled by that.

(Epitaxial wafer manufacturing procedure)
Next, a series of operations of loading the semiconductor wafer W into the process chamber 102, vapor phase growth of the epitaxial film on the semiconductor wafer W, and unloading the manufactured epitaxial wafer out of the process chamber 102 are shown in FIG. Description will be made with reference to A), (B), and (C) as appropriate.

  First, the lift pins 130 are attached, and the transfer operation of the semiconductor wafer W in the temperature range of 600 ° C. to 900 ° C. is adjusted at room temperature. Hereinafter, the adjustment of the transfer operation of the semiconductor wafer W will be described with reference to FIG. First, a heating unit such as the heating lamp 110 is removed. Next, the on-off valve 119 is opened to allow the process chamber 102 and the transfer chamber 103 to communicate with each other. Next, the semiconductor wafer W is placed on the transfer blade 118c, and the transfer arm 118b is rotated and expanded / contracted by a stepping motor (not shown), and the semiconductor wafer W is placed in the process chamber 102 as shown in FIG. Carry in. Next, the semiconductor wafer W is transferred from the transfer blade 118c to each lift pin 130. Next, the transfer arm 118 b is contracted, and the transfer blade 118 c is retracted from the process chamber 102. At this time, the semiconductor wafer W is temporarily supported by the lift pins 130. Next, the susceptor support shaft 100 is raised to move the susceptor 120 to the position of the semiconductor wafer W, and the semiconductor wafer W is placed on the susceptor 120. Thereafter, it is visually confirmed from above the upper dome 104 whether or not the center of the semiconductor wafer W and the center of the susceptor 120 coincide with each other. When the center of the semiconductor wafer W and the center of the susceptor 120 do not coincide with each other, the transport operation is adjusted after the semiconductor wafer W is once taken out from the process chamber 102. That is, by lowering the susceptor support shaft 100, the susceptor 120 is lowered and the semiconductor wafer W is temporarily supported by the lift pins 130. Next, the transfer arm 118 b is extended to introduce the transfer blade 118 c into the process chamber 102, the semiconductor wafer W is transferred from each lift pin 130 to the transfer blade 118 c, and the semiconductor wafer W is taken out from the process chamber 102. Thereafter, the number of operation steps of rotation and expansion / contraction of the transfer arm 118b is changed. This series of operations is repeated until the center of the semiconductor wafer W coincides with the center of the susceptor 120. In the above operation, as the susceptor support shaft 100 is moved up and down, the lift pins 130 slide through the through holes 122 of the susceptor and the through holes 40 of the arms.

  Next, the inside of the process chamber 102 is preliminarily heated to a temperature of 600 ° C. or more and 900 ° C. or less by the heating lamp 110. Thereafter, the semiconductor wafer W is loaded into the process chamber 102 by the transfer blade 118c, and the on-off valve 119 is closed. Referring to FIG. 1A, each lift pin 130 (one not shown) moves upward of the susceptor 120, and the upper end portion 132 of each lift pin comes into contact with the back surface of the semiconductor wafer W. The semiconductor wafer W is once supported by the lift pins 130. The lift movement of each lift pin 130 is performed through the lift movement of the elevating shaft 140 that supports these lower end portions 136.

  Next, the susceptor support shaft 100 is raised to move the susceptor 120 to the position of the semiconductor wafer W, and the semiconductor wafer W is placed on the susceptor 120. Subsequently, with the semiconductor wafer W placed on the susceptor 120, the susceptor support shaft 100 is further lifted to bring the semiconductor wafer W to a height position of the gas supply port 112 as shown in FIG. To move. Referring to FIG. 1B, in this state, upper ends 132 (one not shown) of each lift pin are accommodated in the respective through holes 122 (one not shown) of the susceptor 120. Thereafter, the semiconductor wafer W is heated to a temperature of 1100 ° C. or more and 1200 ° C. or less by the heating lamp 110, while a reaction gas is supplied from the gas supply port 112 into the process chamber 102, and an epitaxial film having a predetermined thickness is formed into a gas phase Growing to produce an epitaxial wafer. During vapor phase growth, the susceptor support shaft 100 is rotated about the main column 10 as a rotation axis, thereby rotating the susceptor 120 and the semiconductor wafer W thereon.

  Thereafter, the susceptor 120 is lowered by lowering the susceptor support shaft 100 in a temperature range of 600 ° C. to 900 ° C. Referring to FIG. 1A, this lowering is performed until each lift pin 130 (one is not shown) is supported by lift shaft 140 and protrudes from susceptor 120, and the manufactured epitaxial wafer is moved to each lift pin 130. I will support it. Then, the on-off valve 119 is opened, the transfer blade 118c is introduced into the process chamber 102, the lift pins 130 are lowered, and the epitaxial wafer is placed on the transfer blade 118c. In this way, the epitaxial wafer is transferred from each lift pin 130 to the transfer blade 118c. Thereafter, the epitaxial wafer is carried out of the process chamber 102 together with the transfer blade 118c.

  In the following, the technical significance of adopting the characteristic configuration of the present invention in the through holes of the arms constituting the susceptor support shaft will be described. First, the through holes 40 of the arms in the susceptor support shaft 100 according to the first embodiment of the present invention will be described with reference to FIGS. 4 (A) to 4 (E) and FIGS. 5 (A) and 5 (B) as appropriate. .

(Arm through hole in the first embodiment)
4A, the inner wall of the through hole 40 of each arm includes a first inner wall 42 that defines a cylindrical first space having a central axis parallel to the axis of the main column, and the first inner wall. Extending from the upper end 42A to the opening end 34A on the upper surface of the arm, defining a second inner wall 44 that defines a second space communicating with the first space, and extending from the lower end 42B of the first inner wall to the opening end 34B on the lower surface of the arm. And a third inner wall 46 that defines a third space communicating with the first space. Further, referring to FIGS. 4B and 4D, when viewed in the direction of the central axis X of the cylindrical shape, the opening end 34A on the upper surface of the arm and the opening end 34B on the lower surface of the arm are the upper end 42A of the first inner wall. And the lower end 42B. Further, referring to FIG. 4A, the second inner wall 44 and the third inner wall 46 are straight in all cross sections passing through the cylindrical central axis X. Furthermore, referring to FIG. 4C, in a cross section passing through the cylindrical central axis X and parallel to the extending direction of the arm, the straight line 44A on the support pin side of the second inner wall and the main inner wall of the third inner wall The straight line 46B on the column side is inclined with respect to the cylindrical central axis X, and the straight line 44B on the main column side of the second inner wall and the straight line 46A on the support pin side of the third inner wall are cylindrical. Inclined with respect to the central axis X of the shape. Hereinafter, the technical significance of adopting the characteristic configuration of the present invention in the shape of the through hole 40 of each arm will be described with reference to FIGS. 4 and 5 as appropriate.

  Referring to FIG. 5A, the epitaxial growth is performed in a temperature range of 1100 ° C. or more and 1200 ° C. or less in a state where the central axis of each lift pin 130 is inclined outward in the radial direction of susceptor 120. At this time, a by-product adheres to the vicinity of the opening end of the through hole 40 of each arm due to the wraparound of the raw material gas or the like. Then, following the epitaxial growth step, the susceptor support shaft 100 is lowered in a temperature range of 600 ° C. or more and 900 ° C. or less with the by-product attached, thereby lowering the susceptor 120. At this time, each lift pin 130 slides with the through hole 40 of each arm and each through hole 122 of the susceptor. At this time, the second space and the third space are inclined to the side surface of the straight body portion 134 of each lift pin by inclining the second inner wall 44 and the third inner wall 46 with respect to the cylindrical central axis X as in the present invention. It functions as a relief part for dispersing the stress accompanying the contact with the by-product. Therefore, stress concentration around the open end of the through hole 40 of each arm can be reduced. As a result, the by-product is hardly peeled off and the generation of sliding dust is suppressed, so that the LPD on the surface of the epitaxial wafer is suppressed and an epitaxial wafer having high flatness can be obtained.

  In addition, referring to FIG. 5B, the attachment of each lift pin 130 and the visual confirmation of the transfer operation of the semiconductor wafer W in the temperature range of 600 ° C. or more and 900 ° C. or less indicate that the central axis of each lift pin 130 is the susceptor 120. It is performed in a state tilted radially inward. At this time, the second space and the third space are inclined to the side surface of the straight body portion 134 of each lift pin by inclining the second inner wall 44 and the third inner wall 46 with respect to the cylindrical central axis X as in the present invention. And functions as a relief part for dispersing stress caused by contact with each arm 30 and rubbing. Therefore, sliding dust generation caused by rubbing between the lift pins 130 and the arms 30 is suppressed, so that LPD on the surface of the epitaxial wafer is suppressed. Further, since the stress is dispersed as described above, the sliding resistance is suppressed. Thereby, since the precision of the conveyance confirmation of the semiconductor wafer W improves, the epitaxial wafer which has high flatness can be obtained.

In addition, referring to FIG. 4C, in the cross section passing through the cylindrical central axis X and parallel to the extending direction of the arm, the angles defined as follows are D <45 °, E <45 °. F <45 ° and G <45 ° are preferably satisfied.
Note D: Angle E formed by the straight line 44A on the support pin side of the second inner wall and the central axis X of the cylindrical shape: Straight line 44B on the main column side of the second inner wall and the central axis X of the cylindrical shape An angle F formed between the straight line 46B on the main column side of the third inner wall and the central axis X of the cylindrical shape: A straight line on the support pin side 46A of the third inner wall and the central axis of the cylindrical shape In this way, the angles D, E, F, and G satisfy less than 45 °, respectively, so that the strength of the susceptor support shaft 100 necessary for holding the susceptor 120 can be secured. Moreover, the volume of the space in which a by-product tends to adhere can be suppressed. From the viewpoint of further reducing the above-mentioned sliding resistance, the angles D, E, F, and G are 30 ° <D <40 °, 5 ° <E <15 °, 30 ° <F <40 °, 5 It is more preferable that ° <G <15 °.

Also, referring to FIG. 4E, in the cross section passing through the cylindrical central axis X and perpendicular to the extending direction of the arm, the angles defined as follows are H <10 °, I <10 °. It is preferable to satisfy.
H: Angle formed by the straight line of the second inner wall 44 and the central axis X of the cylindrical shape I: Angle formed by the straight line of the third inner wall 46 and the central axis X of the cylindrical shape. When each I satisfies less than 10 °, each lift pin 130 can be prevented from wobbling in the circumferential direction of the susceptor 120.

  4C, it is preferable that 0 ° <D + E <45 ° from the viewpoint of securing the strength of the susceptor support shaft 100 required to hold the susceptor 120. Furthermore, from the same viewpoint, it is preferable that 0 ° <F + G <45 °.

  Further, referring to FIG. 4C, it is preferable that D = F and / or E = G. Referring to FIG. 5A, at the time of epitaxial growth, the central axis of each lift pin 130 is inclined outward in the radial direction of the susceptor due to the above-described difference in thermal expansion coefficient. By setting D = F, the center axis of each lift pin 130 can be smoothly inclined toward the radially outer side of the susceptor 120 as the temperature in the process chamber rises to the temperature during epitaxial growth. Thereby, the surface of the semiconductor wafer W can be more accurately parallel to the horizontal plane during epitaxial growth. Therefore, the flatness characteristic of the epitaxial wafer is further improved. 5B, at the normal temperature, the center axis of each lift pin 130 is inclined inward in the radial direction of the susceptor 120 due to the above-described difference in thermal expansion coefficient. By setting E = G, the center axis of each lift pin 130 can be smoothly inclined radially inward of the susceptor 120 at room temperature. Thereby, each lift pin 130 can be moved up and down smoothly. As a result, variations in placing the semiconductor wafer W on the susceptor 120 can be reduced, and the flatness characteristics of the epitaxial wafer are improved.

  As described above, in the through hole 40 of each arm in the first embodiment 100 of the present invention shown in FIGS. 4A to 5E and FIGS. 44A, the straight line 44B on the main column side of the second inner wall, the straight line 46A on the support pin side of the third inner wall, and the straight line 46B on the main column side of the third inner wall are all inclined with respect to the cylindrical central axis X. However, the shape of the through hole of the arm in the present invention is not limited to this, and may be a through hole as shown in FIGS. 6 (A) to (D) and FIGS. 7 (A) to (D). Below, with reference to FIG.6 and FIG.7 suitably, the through-hole of the arm in the susceptor support shaft 200 of 2nd embodiment of this invention and the susceptor support shaft 300 of 3rd embodiment is demonstrated. In addition, in 2nd embodiment and 3rd embodiment, the same member as 1st embodiment is demonstrated using the same code | symbol.

(Arm through hole in the second embodiment)
Referring to FIG. 6C, the through holes 40 of the arms in the susceptor support shaft 200 according to the second embodiment of the present invention have 0 ° <D <45 ° and E = 0 ° (FIG. 6C). In FIG. 6, E may not be a through hole satisfying 0 ° <F <45 ° and G = 0 ° (in FIG. 6C, G is not shown). Epitaxial growth is performed in a temperature range of 1100 ° C. or more and 1200 ° C. or less with the center axis of each lift pin 130 tilted radially outward of the susceptor 120. Accordingly, the straight line 44A on the support pin side of the second inner wall and the straight line 46B on the main column side of the third inner wall are 0 ° <D <45 ° and 0 ° <F <45 ° with respect to the central axis X of the cylinder. By inclining so as to satisfy, the above-described stress relief portion can be secured, so that generation of sliding dust can be suppressed as compared with a conventional susceptor support shaft for an epitaxial growth apparatus. The technical significance of setting the angles D and F within the above range is as described above.

  Note that, with reference to FIG. 6C, 0 ° <D + E <45 ° is preferable, and 0 ° <F + G <45 ° is more preferable. Further, it is preferable that D = F and / or E = G. Furthermore, it is preferable that H <10 ° and I <10 ° are satisfied also in the through hole of the arm in the second embodiment. These reasons are the same as those described in the first embodiment.

(Through hole in the third embodiment)
Next, referring to FIG. 7C, the through hole 40 of each arm in the susceptor support shaft 300 according to the third embodiment of the present invention has D = 0 ° (in FIG. 7C, D is a figure). (Not shown), 0 ° <E <45 °, F = 0 ° (in FIG. 7C, F is not shown) and 0 ° <G <45 °. The attachment of each lift pin 130 and the visual confirmation of the transfer operation of the semiconductor wafer W are performed in a state where the central axis of each lift pin 130 is inclined inward in the radial direction of the susceptor 120. Accordingly, the straight line 44B on the main column side of the second inner wall and the straight line 46A on the support pin side of the third inner wall are 0 ° <E <45 ° and 0 ° <G <45 ° with respect to the cylindrical central axis X. By tilting so as to satisfy, it is possible to secure an escape portion for dispersing stress caused by contact and rubbing between the side surface of the straight body portion 134 of each lift pin and each arm 30. Therefore, the conventional susceptor for an epitaxial growth apparatus Compared to the support shaft, it is possible to suppress the generation of sliding dust at room temperature. The technical significance of setting the angles E and G in the above range is as described above.

  Referring to FIG. 7C, 0 ° <D + E <45 ° is preferable, and 0 ° <F + G <45 ° is more preferable. Further, it is preferable that D = F and / or E = G. Furthermore, it is preferable that H <10 ° and I <10 ° are also satisfied in the through hole of the arm in the third embodiment. These reasons are the same as those described in the first embodiment.

  As described above, the technical significance regarding the inclination of the second inner wall and the third inner wall among the shapes of the through holes of the arms in the first to third embodiments of the present invention has been described, but the present invention will be described below. By adopting such a configuration, a further additional effect can be obtained.

  First, referring to FIG. 4C, FIG. 6C, and FIG. 7C, the height C of the first space in the first to third embodiments is 8.00 mm or more and 14.00 mm or less. It is preferable that If it is 8.00 mm or more, the wobbling of each lift pin 130 can be further suppressed, so that the lift pin can be lifted and lowered more smoothly, and the reliability of the transport operation of the semiconductor wafer W is further improved. The upper limit value can be set as appropriate in relation to the thickness of the arm 30. However, by setting the upper limit value to 14.00 mm or less, infrared rays or the like by the heating lamp 110 located in the lower region of the process chamber 102 can be used. It does not interfere with irradiation to the susceptor 120.

  4C, FIG. 6C, and FIG. 7C, the length L1 of the straight line 44A on the support pin side of the second inner wall and the straight line 46B on the main column side of the third inner wall. Is preferably 10.0 mm or more and 15.0 mm or less. The length L2 of the straight line 44B on the main pillar side of the second inner wall and the straight line 46A on the support pin side of the third inner wall is preferably 1.0 mm or more and 3.0 mm or less. By setting it as such length, generation | occurrence | production of sliding dust can be suppressed.

  Next, in order to form a high-quality epitaxial film, it is required to perform epitaxial growth in a state close to a set temperature. Therefore, during epitaxial growth, the temperature is controlled while detecting the temperature of the surface to be processed of the semiconductor wafer W by the upper pyrometer 116a. However, when the temperature of the semiconductor wafer W is raised from the transfer temperature to the epitaxial growth temperature, the temperature is controlled based on the difference between the detected values of the upper and lower pyrometers 116a and 116b. Next, at the time of gas cleaning for removing by-products resulting from epitaxial growth, the temperature is controlled while detecting the temperature of the back surface of the susceptor 120 by the lower pyrometer 116b. At this time, in order to improve the accuracy of temperature detection and temperature control, it is preferable that the arm 30 is thin so that the arm 30 does not block between the lower pyrometer 116b and the back surface of the susceptor 120. However, from the viewpoint of suppressing sliding dust generation and improving the reliability of the conveying operation, as described with reference to FIGS. 4C, 6C, and 7C, C, L1 and L2 need to be predetermined values. Therefore, from the viewpoint of maintaining the accuracy of temperature detection and temperature control by the lower pyrometer 116b while setting the above C, L1, and L2 to predetermined values, as shown in FIG. It is preferable that it is thicker than other parts only in the peripheral part of the through-hole 40 along the existing direction. Specifically, the thickness J of the arm around the through hole 40 is preferably 11.00 mm or more and 20.00 mm or less. If it is 20.00 mm or less, the accuracy of temperature detection and temperature control can be maintained. By setting the length to 11.00 mm or more, the length C can be secured, and the strength of the susceptor support shaft 400 necessary for holding the susceptor 120 can be obtained. That is, by ensuring this strength, even when the susceptor support shaft 400 is continuously used, plastic deformation such as twisting and bending of the arm 30 is suppressed. Note that the peripheral portion of the arm 40 in this specification means that the distance from the cylindrical central axis X is within 15.0 mm in a cross section passing through the cylindrical central axis X and parallel to the extending direction of the arm. A region, that is, a region where K shown in FIG. 8 is within 30.0 mm.

  Next, referring to FIG. 4C, FIG. 6C, and FIG. 7C, the diameter B of the first space in the first to third embodiments suppresses wobbling of the lift pins. From the viewpoint, it can be set as appropriate in consideration of the diameter A of the straight body portion 134 of each lift pin. Generally, the diameter A of the straight body portion of the lift pin is not less than 3.25 mm and not more than 3.45 mm. The diameter B of the first space is preferably 0.5 mm larger than A, and specifically, 3.75 mm <B <3.95 mm.

  Next, the shape of the opening end 34A on the upper surface of the arm and the opening end 34B on the lower surface of the arm in the first to third embodiments is not limited to an ellipse or an ellipse, and FIGS. 6 (B), (D), and FIGS. 7 (B), (D), the opening end 34A on the upper surface of the arm and the opening end on the lower surface of the arm when viewed in the direction of the central axis X of the cylindrical shape. 34B only needs to surround the upper end 42A and the lower end 42B of the first inner wall.

  In the first to third embodiments, the example in which the three arms 30 are extended at equal intervals in the direction branched from the main pillar 10 is shown, but the present invention is not limited to this. Four or more may be branched.

(Invention Example 1)
First, the following susceptor support shaft was prepared. That is, referring to FIG. 4C, the shape of the through hole of the susceptor is B = 3.89 mm, C = 10.99 mm, D = 35 °, E = 10 °, F = D, and G = E. Set to. Next, referring to FIG. 4B, the shape of the open end on the upper surface of the arm was an ellipse having R1 of 9.50 mm and R1 ′ of 5.70 mm. Next, referring to FIG. 4D, the shape of the open end of the lower surface of the arm was an ellipse with R2 of 9.50 mm and R2 ′ of 5.70 mm. Next, referring to FIG. 4 (E), settings were made such that H = 10.0 ° and I = 10.0 °. Next, referring to FIG. 8, the arm thickness J in the periphery of the through hole was 17.30 mm, and K was 30.0 mm. Quartz was used for the susceptor support shaft.

  Subsequently, the epitaxial growth apparatus shown in FIG. 1 was configured using the susceptor support shaft. The horizontal cross-sectional shape of the lift pin was a circle, and the diameter A was set to be 3.35 mm. The susceptor used was a member obtained by coating a carbon graphite base material with silicon carbide.

  Subsequently, the transfer operation of the semiconductor wafer at room temperature was adjusted by the method described above. Next, the semiconductor wafer was transported at 700 ° C. Then, the silicon epitaxial wafer was manufactured according to the procedure mentioned above. As the substrate of the silicon epitaxial wafer, a boron-doped silicon wafer having a diameter of 300 mm was used.

  In the manufacture of the epitaxial wafer, first, trichlorosilane gas as a source gas was supplied at a temperature of 1150 ° C., and silicon coating was applied to the surface of the susceptor. Next, the silicon wafer was introduced into the process chamber and placed on the susceptor using lift pins. Subsequently, hydrogen gas was supplied at 1150 ° C. to perform hydrogen baking, and then an epitaxial silicon film was grown at 1150 ° C. by 4 μm to obtain an epitaxial silicon wafer. Here, trichlorosilane gas was used as the source gas, diborane gas was used as the dopant gas, and hydrogen gas was used as the carrier gas.

(Invention Example 2)
Referring to FIG. 6C, D = F = 35 ° and E = G = 0 °. Referring to FIG. 6B, R1 of the opening end of the upper surface of the arm is 8.6 mm, and R1 ′ is 5.7 mm, referring to FIG. 6D, using an epitaxial growth apparatus having the same configuration as in Invention Example 1 except that the opening end R2 of the lower surface of the arm is 8.6 mm and R2 ′ is 5.7 mm, An epitaxial wafer was manufactured.

(Invention Example 3)
Referring to FIG. 7C, E = G = 10 ° and D = F = 0 °, and referring to FIG. 7B, R1 of the opening end of the upper surface of the arm is 4.8 mm, and R1 ′ is Referring to FIG. 7D, using an epitaxial growth apparatus having the same configuration as that of Invention Example 1 except that the opening end R2 of the lower surface of the arm is 4.8 mm and R2 ′ is 5.7 mm, An epitaxial wafer was manufactured.

(Comparative Example 1)
10A to 10C, a conventional susceptor support shaft, that is, a susceptor support shaft in which D = E = F = G = 0 ° and the arm thickness is constant in the extending direction of the arm. The epitaxial wafer was manufactured using the epitaxial growth apparatus which has the structure similar to invention example 1 except having used.

(Evaluation method)
In each invention example and comparative example, an epitaxial wafer was manufactured through the above-described series of processes including the transfer operation and epitaxial growth of the silicon wafer, and the following evaluation was performed. It should be noted that the above-described series of steps are continuously performed 10 times, and the process chamber is not cleaned during that time. Further, the adjustment of the silicon wafer transfer operation at room temperature was performed only before the first silicon wafer transfer operation at 700 ° C. was performed.

(LPD evaluation)
The number of LPDs (light point defects) on the surface of the epitaxial film was evaluated by the following method. The surface of the epitaxial film is observed and evaluated in DWO mode (Dark Field Wide Oblique mode: dark field, wide, oblique incidence mode) using a surface defect inspection system (KLA-Tencor: Surfscan SP-2). ) Was examined for the occurrence of LPD of 0.2 μm or more. The measurement results are shown in Table 1.

(Evaluation of flatness)
The flatness of the epitaxial film was evaluated by the following method. The flatness (ESFQR value) of the outer peripheral surface of the epitaxial wafer was measured using an optical interference displacement meter (manufactured by KLA-Tencor, WaferSight). The measurement results are shown in Table 1.

(Explanation of evaluation results)
First, as for LPD, Invention Examples 1 to 3 were able to suppress the generation of LPD having a size (diameter) of 0.2 μm or more as compared with Comparative Example 1. As for the flatness, the average value of 10 flatnesses was 47.5 nm on average in Comparative Example 1, whereas 35.5 nm on average in Invention Example 1, 37.0 nm on average in Invention Example 2, and Example 3 The average value was 37.9 nm. Inventive Examples 1 to 3 had higher flatness than Comparative Example 1.

  According to the susceptor support shaft and the epitaxial growth apparatus of the present invention, LPD is suppressed by suppressing the generation of sliding dust caused by by-products generated during epitaxial growth and sliding dust generation during adjustment of the semiconductor wafer transfer operation. An epitaxial wafer which is suppressed and has high flatness can be manufactured.

1000 epitaxial growth apparatus 102 process chamber 103 transfer chamber 104 upper dome 106 lower dome 108 dome mounting body 110 heating lamp 112 gas supply port 114 gas discharge port 116a upper pyrometer
116b Lower pyrometer
118a transfer robot 118b transfer arm 118c transfer blade 119 on-off valve 120 susceptor 122 through hole of susceptor 100, 200, 300, 400 susceptor support shaft 10 main pillar 20 support pin 30 arm
32A Upper surface of the arm 32B Lower surface of the arm 34A Open end of the upper surface of the arm 34B Open end of the lower surface of the arm 40 Arm through hole 42 First inner wall 42A Upper end of the first inner wall 42B Lower end of the first inner wall 44 Second inner wall 44A Second Straight line on the support pin side of the inner wall 44B Straight line on the main pillar side of the second inner wall 46 Third inner wall 46A Straight line on the support pin side of the third inner wall 46B Straight line on the main pillar side of the third inner wall 130 Lift pin 132 Upper end (head)
134 Straight body portion 136 Lower end portion 140 Lifting shaft 142 Main pillar of lifting shaft 144 Support column W Semiconductor wafer

Claims (12)

A susceptor support shaft for supporting the susceptor from below in an epitaxial growth apparatus for vapor-phase growth of an epitaxial film on the surface of a semiconductor wafer placed on the susceptor;
A main pillar disposed substantially coaxially with the center of the susceptor;
Three or more arms extending radially from the main pillar to the lower periphery of the susceptor;
A support pin that is provided at each end of the arm and directly supports the susceptor;
The arm is provided with a through-hole penetrating the arm from its upper surface toward its lower surface,
The inner wall of the through hole is
A first inner wall defining a cylindrical first space having a central axis parallel to the axis of the main pillar;
A second inner wall extending from an upper end of the first inner wall to an opening end of the upper surface of the arm, and defining a second space communicating with the first space;
A third inner wall that extends from the lower end of the first inner wall to the opening end of the lower surface of the arm and defines a third space that communicates with the first space;
Have
When viewed in the central axis direction of the cylindrical shape, the open end of the upper surface of the arm and the open end of the lower surface of the arm surround the upper end and the lower end of the first inner wall,
The second inner wall and the third inner wall are straight in all cross sections passing through the cylindrical central axis,
In a cross section passing through the central axis of the cylindrical shape and parallel to the extending direction of the arm, a straight line on the support pin side of the second inner wall and a straight line on the main column side of the third inner wall are the cylinder. And / or the straight line on the main column side of the second inner wall and the straight line on the support pin side of the third inner wall are inclined with respect to the central axis of the cylinder. A susceptor support shaft characterized by being inclined. In a cross section passing through the central axis of the cylindrical shape and parallel to the extending direction of the arm, angles defined as follows satisfy D <45 °, E <45 °, F <45 °, and G <45 °. The susceptor support shaft according to claim 1, wherein the susceptor support shaft is filled.
D: Angle formed by a straight line on the support pin side of the second inner wall and the central axis of the cylindrical shape E: Angle F formed by a straight line on the main column side of the second inner wall and the central axis of the cylindrical shape : Angle G formed by the straight line on the main pillar side of the third inner wall and the central axis of the cylindrical shape: Angle formed by the straight line on the support pin side of the third inner wall and the central axis of the cylindrical shape   The susceptor support shaft according to claim 2, satisfying 0 ° <D <45 °, 0 ° <E <45 °, 0 ° <F <45 °, and 0 ° <G <45 °.   The susceptor support shaft according to claim 2, satisfying 0 ° <D <45 °, E = 0 °, 0 ° <F <45 °, and G = 0 °.   The susceptor support shaft according to claim 2, wherein D = 0 °, 0 ° <E <45 °, F = 0 °, and 0 ° <G <45 °.   The susceptor support shaft according to any one of claims 2 to 5, wherein 0 ° <D + E <45 °.   The susceptor support shaft according to any one of claims 2 to 6, wherein 0 ° <F + G <45 °.   The susceptor support shaft according to any one of claims 2 to 7, wherein D = F and / or E = G.   The susceptor support shaft according to any one of claims 1 to 8, wherein a height C of the first space is 8.00 mm to 14.00 mm.   The susceptor support shaft according to any one of claims 1 to 9, wherein a thickness of the arm is thicker than other portions only in a peripheral portion of the through hole along an extending direction thereof.   The susceptor support shaft according to claim 10, wherein a thickness of the arm around the through hole is 11.00 mm or more and 20.00 mm or less. An epitaxial growth apparatus for vapor-phase growing an epitaxial film on the surface of a semiconductor wafer,
A process chamber;
A susceptor for mounting the semiconductor wafer in the process chamber;
The susceptor support shaft according to any one of claims 1 to 11, which supports the susceptor from below;
Three or more lift pins that are inserted into the respective through holes of the three or more arms and are moved up and down in a vertical direction to attach and detach the semiconductor wafer to and from the susceptor;
An epitaxial growth apparatus comprising:

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