JP2016225445A - Epitaxial growth device, method for manufacturing epitaxial wafer, and lift pin for epitaxial growth device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lift pin for an epitaxial growth device capable of reducing generation of defects on a rear surface of an epitaxial silicon wafer and adhesion of particles to a surface of the wafer.SOLUTION: An epitaxial growth device comprises a support shaft including a susceptor 4 mounted with a silicon wafer W and a support arm 17b supporting the susceptor 4 from below, and a lift pin 15 inserted into both through holes 4h and 17h provided in the susceptor and the support arm 17b and movably disposed in a vertical direction. This device attaches and detaches the silicon wafer W to and from the susceptor 4 by elevating and lowering the lift pin 15. At least a surface layer region of the lift pin 15 is composed of a material having lower hardness than the susceptor 4. A lower region 15c in a straight body part of the lift pin 15 passing in the through hole 17h of the support arm 17b is provided with a lost part for reducing an area which can come into contact with the support arm 17b.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an epitaxial growth apparatus, an epitaxial wafer manufacturing method, and a lift pin for an epitaxial growth apparatus, and more particularly to an epitaxial growth apparatus capable of reducing the generation of wrinkles on the back surface of an epitaxial silicon wafer and reducing the adhesion of particles to the wafer surface. The present invention relates to a manufacturing method and a lift pin for an epitaxial growth apparatus.

  In general, silicon wafers are grown by growing single crystal silicon by the Czochralski (CZchralski, CZ) method, etc., cutting the silicon single crystal into blocks, slicing it thinly, surface grinding (lapping) process, etching process and mirror surface It is obtained by final cleaning through a polishing (polishing) step. After that, various quality inspections are performed and if no abnormality is confirmed, the product is shipped as a product.

  Here, when crystal integrity is more demanded or when a multilayer structure having different resistivity is required, a single crystal silicon thin film is vapor-phase grown (epitaxially grown) on the silicon wafer. To manufacture.

  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. 1, the epitaxial growth apparatus 100 has a chamber 2 surrounded by an upper dome 11, a lower dome 12, and a dome mounting body 13. The chamber 2 is provided with a gas supply port 31 and a gas discharge port 32 for supplying and discharging a reaction gas at positions opposite to the side surfaces.

  On the other hand, a susceptor 4 on which the silicon wafer W is placed is disposed in the chamber 2. The outer periphery of the lower surface of the susceptor 4 is supported by a support arm 7b connected to a rotatable main column 7a, and rotates together with the support arm 7b. The susceptor 4 and the support arm 7b are formed with through holes 4h and 7h through which lift pins 5 for moving the silicon wafer W up and down are passed. The lift pin 5 is lifted and lowered with its base end supported by the lift shaft 6.

  That is, the silicon wafer W introduced into the chamber 2 moves the lift pins 5 inserted through the through holes 4h of the susceptor 4 and the through holes 7h of the support arm 7b toward the upper side of the susceptor 4, and the head of the lift pins 5 is moved to the silicon. The silicon wafer W is temporarily supported by lift pins 5 while being brought into contact with the back surface of the wafer W. Here, the upward movement of the lift pin 5 is performed through the upward movement of the lift shaft 6 that supports the base end of the lift pin 5.

  Next, the support shaft 7 that supports the susceptor 4 is raised to move the susceptor 4 to the position of the silicon wafer W, and the silicon wafer W is placed on the susceptor 4. In this state, the head of the lift pin 5 is accommodated in the enlarged diameter portion (not shown) of the through hole 4 h of the susceptor 4. As described above, the silicon wafer W is placed on the susceptor 4 and, for example, the silicon wafer W is heated to a temperature of 1000 ° C. or more by a plurality of heating lamps 14 disposed above and below the susceptor 4 while forming an epitaxial film. A reactive gas is supplied into the chamber 2 to grow an epitaxial film having a predetermined thickness to manufacture an epitaxial wafer.

  Thereafter, the susceptor 4 is lowered by the lowering of the support arm 7b. This lowering is performed until the lift pins 5 are supported by the lift shaft 6 and protrude from the susceptor 4, and the silicon wafer W is supported by the lift pins 5. Then, a transfer blade (not shown) is introduced into the chamber 2, the lift pin 5 is lowered, and the silicon wafer W is placed on the transfer blade, whereby the silicon wafer W is transferred from the lift pin 5 to the transfer blade. Thereafter, the silicon wafer W is withdrawn from the growth apparatus 100 together with the transfer blade.

  With the recent miniaturization and high integration of semiconductor devices, reduction of crystal defects and particles adhering to the wafer surface is required. Against this background, Patent Document 1 focuses on the wear caused by the sliding of the lift pins, forms the surfaces of the lift pins and the susceptor with silicon carbide (SiC), and polishes the region of the lift pins that are in contact with the susceptor. It is described that by setting the surface roughness to 0.2 μm to 5 μm, particle adhesion and crystal defect formation that occur during epitaxial growth can be reduced.

JP 2002-299260 A

In the invention described in Patent Document 1, since the material of the lift pin surface is composed of SiC, there is a problem that contact wrinkles occur at the back surface portion of the wafer that contacts the top of the lift pin when the lift pin is raised and lowered.
That is, not only the invention described in Patent Document 1, but generally, the susceptor 4 is a carbon substrate coated with SiC, or the substrate itself is made of SiC from the viewpoint of heat resistance and acid resistance. In the same manner, a lift pin is used in which a carbon base material is coated with SiC, or the base material itself is made of SiC.

  However, although SiC is excellent in heat resistance and acid resistance, its hardness is high. Therefore, when a lift pin made of SiC is used, when the tip of the lift pin 5 comes into contact with the back surface of the silicon wafer W, the back surface of the wafer W There is a problem of generating contact wrinkles and contact marks. In the current highly integrated device, there is a demand for reducing contact wrinkles on the back surface of the wafer W due to contact between the back surface of the silicon wafer W and the lift pins 5 as much as possible. There is a need to provide an epitaxial silicon wafer.

  An object of the present invention is to propose an epitaxial growth apparatus, an epitaxial wafer manufacturing method, and a lift pin for an epitaxial growth apparatus that can reduce the generation of wrinkles on the back surface of the epitaxial silicon wafer and reduce the adhesion of particles to the wafer surface.

  The inventor reduces the generation of wrinkles on the back surface of the silicon wafer by configuring the material of the lift pins 5 with a material whose hardness is lower than that of SiC, and adjusts the surface roughness of the lift pins 5 to thereby generate particles. As a result of various experiments, the following knowledge was obtained.

  First, when lift pins 5 were made of a material having a hardness lower than that of the susceptor 4 and epitaxial growth processing was performed, it was confirmed that the generation of contact flaws on the back surface of the silicon wafer W can be significantly reduced. It was confirmed that the adhesion amount of particles increased.

  The inventor presumes that the particles adhere to the wafer surface due to the generation of particles due to the contact between the susceptor 4 and the lift pins 5, and the surface roughness in the region in contact with the susceptor 4 is made as small as possible. Experiments were performed using lift pins 5. As a result, the effect of reducing the amount of adhered particles on the wafer surface was confirmed, but it was newly confirmed that an abnormal phenomenon in which the amount of adhered particles on the wafer surface suddenly increases frequently occurs.

  Since this sudden increase in particles occurs suddenly, it is expected that some trouble has occurred during the epitaxial growth process. For this reason, the inventor confirmed whether the raising / lowering operation | movement of the lift pin 5 was normally performed during the epitaxial growth process. Specifically, with the chamber 2 opened, the source gas or the like is not flowed, and the silicon wafer W is placed on the susceptor 4 at room temperature, and the lift shaft 5 is driven to lift the lift pins 5 up and down. The experiment was performed by repeating the operation and visually confirming the lifting and lowering operation of the lift pins 5.

  As a result, when the lift shaft 6 is lowered and the lift pins 5 are lowered downward, some of the lift pins 5 are caught in the through holes 4h of the support arm 7b, and the lift pins 5 are not lowered, and thereafter the catch is released and the lift pins are released. It was confirmed that 5 fell down vigorously.

  It is presumed that an abnormal operation in which the lift pin 5 falls during the epitaxial growth process, and the dust generated by the contact between the lift pin 5 and the susceptor 4 due to the drop phenomenon of the lift pin 5 is located above the susceptor 4. Therefore, it is presumed that the amount of particles that wrap around the surface of the silicon wafer W is suddenly increased.

  Therefore, as a result of earnestly examining the way in which the sticking of the lift pins 5 and the support arms 7b can be suppressed to suppress the adhesion of particles to the wafer surface, the inventor in the region of the lift pins passing through the through holes of the support arms, The present inventors have found that it is effective to provide a deficient portion that reduces the area that can be brought into contact with the support arm, and have completed the present invention.

The gist of the present invention is as follows.
(1) A support shaft having a susceptor for placing a silicon wafer inside the chamber, a support that supports the susceptor from below, a support that is coaxial with the center of the susceptor, and a support arm that extends radially from the support. And a lift pin that is inserted through both of the through hole provided in the susceptor and the through hole provided in the support arm and is movably disposed in the vertical direction. In the epitaxial growth apparatus for desorbing a wafer on the susceptor, at least a surface layer region of the lift pin is made of a material having a hardness lower than that of the susceptor, and passes through the through hole of the support arm, and a lower part of the straight body portion of the lift pin An epitaxy characterized in that a defect portion for reducing an area that can contact the support arm is provided in the region. Shall growth apparatus.

(2) The epitaxial growth apparatus according to (1), wherein the ratio of the reduced area is 20% or more and 50% or less of the whole.

(3) In the above (1) or (2), the lift pin has at least a surface region made of glassy carbon, the susceptor has at least a surface region made of hydrocarbon (SiC), and the support arm is made of quartz. The epitaxial growth apparatus described.

(4) Arithmetic mean roughness of at least one of the upper body region of the lift pin passing through the through hole of the susceptor and the wall surface defining the through hole of the susceptor is 0.1 μm or more and 0.3 μm or less The epitaxial growth apparatus according to any one of (1) to (3).

(5) The arithmetic average roughness of both the upper body region of the lift pin that passes through the through hole of the susceptor and the wall surface that defines the through hole of the susceptor is 0.1 μm or more and 0.3 μm or less. The epitaxial growth apparatus according to (4).

(6) The epitaxial growth apparatus according to any one of (1) to (5), wherein a lower end portion of the lift pin is rounded.

(7) A method for producing an epitaxial wafer, comprising growing an epitaxial film on a silicon wafer using the epitaxial growth apparatus according to any one of (1) to (6).

(8) Inserted into both a through hole provided in a susceptor installed in an epitaxial growth apparatus for vapor-phase growth of an epitaxial layer on a silicon wafer and a through hole provided in a support arm that supports a lower portion of the susceptor, A lift pin that supports and lifts the back surface of the silicon wafer when the silicon wafer is carried into the epitaxial growth apparatus or removed from the epitaxial growth apparatus, and at least the surface layer region is made of a material having a hardness lower than that of the susceptor. A lift pin for an epitaxial growth apparatus, further comprising: a deficient portion that reduces an area in contact with the support arm in a lower region of the straight body portion that passes through the through hole of the support arm.

(9) The lift pin for an epitaxial growth apparatus according to (8), wherein at least the surface layer region is made of glassy carbon.

(10) The lift pin for an epitaxial growth apparatus according to (8) or (9), wherein the surface roughness of the upper portion of the straight body portion passing through the through hole of the susceptor is 0.1 μm or more and 0.3 μm or less.

(11) The lift pin for an epitaxial growth apparatus according to any one of (8) to (10), wherein a lower end portion of the lift pin is rounded.

  According to the present invention, generation of wrinkles on the back surface of the epitaxial silicon wafer can be reduced, and adhesion of particles to the wafer surface can be suppressed.

It is a figure which shows a general epitaxial growth apparatus. It is a figure which shows the epitaxial growth apparatus by this invention. It is a figure which shows the peripheral region of the lift pin in the epitaxial growth apparatus by this invention. It is a figure which shows the specific example of the defect | deletion part provided in the area | region (straight trunk | drum lower part area | region) of the lift pin which passes the inside of the through-hole of a support arm. It is a figure which shows the peripheral region of the lift pin in the suitable epitaxial growth apparatus by this invention. It is a figure which shows the relationship between the ratio of the area reduced in the area | region (straight trunk | drum lower part area | region) of the lift pin which passes the inside of the through-hole of a support arm, and the raising / lowering malfunction occurrence rate of a lift pin. It is a figure which shows the relationship between the surface roughness of the area | region (straight trunk | drum upper part area | region) of the lift pin which passes the inside of the through-hole of a susceptor, and the number of LPD per wafer.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 2 shows an epitaxial growth apparatus 1 according to the present invention. FIG. 3 shows a peripheral region of the lift pins 15 in the epitaxial growth apparatus 1. In addition, the same code | symbol is attached | subjected to the same structure as FIG. 1, and description is abbreviate | omitted. As shown in FIGS. 2 and 3, the epitaxial growth apparatus 1 according to the present invention has a lift pin 15 made of a material whose hardness is lower than that of the susceptor 4, that is, a soft material, and the lift pin 15 penetrates the susceptor 4. It is inserted through the hole 4h and the through hole 17h of the support arm 17b, and is arranged to be movable in the vertical direction.

  As shown in FIG. 3, the lift pin 15 has a rod-shaped straight body portion 15a and a head portion 15b having a diameter larger than that of the straight body portion 15a and the through hole 4h. The head portion 15b penetrates the susceptor 4. It is comprised so that it may engage with the enlarged diameter part 4w of the hole 4h. The shape of the lift pin is not limited as long as it has a head portion that directly supports the silicon wafer at the tip of the rod-like straight body portion.

  As described above, the lift pin 15 is made of a material whose hardness is lower than that of the susceptor 4, that is, a soft material. Thereby, generation | occurrence | production of the contact flaw on the back surface of the wafer W can be reduced significantly. Specifically, glassy carbon, graphite, quartz, aluminum nitride, forsterite, cordierite, yttria, steatite, or the like can be used for the lift pin 15. Among these, glassy carbon is excellent in molding processing, and has high purity, heat resistance, and acid resistance. The entire lift pin 15 does not need to be made of the above-described material, and at least the surface layer region may be made of a material softer than the surface material of the susceptor. For example, the lift pin 15 can be configured by covering the surface of a base material having a high hardness such as SiC with the above material.

  The susceptor 4 is composed of a carbon substrate whose surface is covered with SiC or a substrate made of SiC from the viewpoint of heat resistance and acid resistance that can withstand use in a high purity and high temperature environment. It is customary to do this.

  In the present invention, an area that can contact the support arm 17b in a region 15c on the straight body portion 15a of the lift pin 15 that passes through the through-hole 17h of the support arm 17b (hereinafter referred to as a “straight body portion lower region”) 15c. It is important to provide a defect portion D that reduces the above. As described above, when the lift pins 15 are made of a material softer than the susceptor 4, it is found that some lift pins are caught in the through holes of the support arm when the lift shaft is lowered and the lift pins are lowered. did.

  Although this cause is not necessarily clear, the inventor thinks as follows. That is, for example, when the transparent glass sheets having low surface roughness are combined with each other and when the transparent glass sheet and the ground glass are combined, the friction of the contact surface is smaller when one side has unevenness like the ground glass, and the sliding of the contact surface is reduced. This is probably because it has the same effect as becoming larger.

  Therefore, in the present invention, the missing portion D that reduces the area that can be contacted with the support arm 17b is formed in the straight body portion lower region 15c on the straight body portion 15a of the lift pin 15 that passes through the through hole 17h of the support arm 17b. As a result, the probability that the lift pin 15 and the support arm 17b come into contact with each other is reduced, the probability that the lift pin 15 and the support arm 17 are caught is reduced, and the adhesion of particles to the wafer surface is suppressed. It can be done.

  Here, the shape and number of the deficient portions D are not limited as long as the contact surface area with the support arm 17b is reduced. Moreover, it is preferable that the ratio of the area reduced by the defect | deletion part D is 20 to 50% of the whole. Here, by setting the ratio of the reduced area to 20% or more of the whole, it is possible to reduce the failure occurrence rate of the lifting operation of the lift pins 15 to 10%. Moreover, it is preferable that the ratio of the reduced area shall be 50% or less of the whole from the point that the reduction effect of the said malfunction occurrence rate is saturated and the processing cost.

  A specific example of the defect D is shown in FIG. FIG. 4A shows a missing portion having a U-shaped cross section extending in the axial direction of the lift pin 15 in the straight body lower region 15 c of the lift pin 15, and FIG. 4B shows the axial direction of the lift pin 15. The extending cross section shows a V-shaped defect portion D. FIG. 4 (c) shows a circular hollow-shaped defect portion D provided on the surface of the moving portion 15c of the lift pin 15, and FIG. 4 (d) is a cross section taken along a plane parallel to the axis of the lift pin 15. The missing part D is shown.

  In the present invention, as shown in FIG. 5, a region on the straight body portion of the lift pin 15 that passes through the through-hole 4h of the susceptor 4 (hereinafter referred to as “straight body upper region”) 15d, and the susceptor 4 It is preferable that the surface roughness of at least one of the wall surfaces 4s partitioning the through holes 4h is 0.1 μm or more and 0.3 μm or less. In the present invention, since the lift pin 15 is made of a material softer than the susceptor 4, the surface roughness of at least one of the straight body portion upper region 15d of the lift pin 15 and the wall surface 4s that defines the through hole 4h of the susceptor 4 is set. By setting it to 0.3 μm or less, the above-described effect of suppressing dust generation can be achieved. Moreover, by making the surface roughness 0.1 μm or more, generation of dust can be effectively suppressed without increasing the processing cost.

  In the present invention, it is preferable that the surface roughness of both the straight body upper region 15 d of the lift pin 15 and the wall surface 4 s defining the through hole 4 h of the susceptor 4 is 0.1 μm or more and 0.3 μm or less. Thereby, the suppression effect of dust generation can be heightened more.

  Furthermore, since the lower surface portion of the head portion 15b of the lift pin is in contact with the enlarged diameter portion 4w of the through hole 4h of the susceptor 4, the surface roughness of the lower surface portion of the head portion 15b is preferably 0.3 μm or less. The “surface roughness” means the arithmetic average roughness Ra defined in JIS B 0601 (2001).

  Furthermore, in the present invention, it is preferable that the lower end portion of the lift pin 15 is rounded. As described above, the lift pin 15 is inserted into both the through hole 4h of the susceptor 4 and the through hole 17h of the support arm 17b, and is configured to be movable in the vertical direction. At that time, a slight gap (clearance) is provided between the lift pin 15 and the through holes 4h and 17h so that the lift pin 15 can smoothly move in the through holes 4h and 17h.

  For this reason, when the lift pin 15 moves up and down, the lift pin 15 may be inclined and may be out of the track when the lift pin 15 moves up and down. However, the lower end portion of the lift pin 15 is rounded to have a roundness. By doing so, the track of the lift pin 15 can be recovered, and generation of dust due to sliding between the lift pin 15 and the susceptor 4 caused by deviation from the track can be suppressed.

  Thus, according to the present invention, generation of wrinkles on the back surface of the epitaxial silicon wafer can be reduced, and adhesion of particles to the wafer surface can be suppressed.

<Production of lift pins>
Lift pins (Invention Examples 1 to 7 and Comparative Examples) having the specifications shown in Table 1 were produced. At that time, all lift pins were made of glassy carbon.

<Experiment for confirming malfunction of lift pin lifting>
When each of the manufactured lift pins of Invention Examples 1 to 7 and Comparative Example is applied to the epitaxial growth apparatus 1 shown in FIG. 2 and the lift pins are moved up and down while the silicon wafer W is placed on the susceptor, the operation is performed. An operation confirmation experiment was conducted to confirm whether or not a failure occurred. This operation confirmation experiment was performed in a room temperature state where the upper dome 11 of the epitaxial growth apparatus 1 was opened, and the occurrence of an operation failure was confirmed visually. The number of lifting operations was 50, and the reciprocating operation was counted as one.

  FIG. 6 shows the relationship between the reduced surface area ratio of the straight body lower area and the occurrence rate of lifting pins. As is apparent from FIG. 6, the rate of occurrence of lift pin lifting / lowering defects decreases as the proportion of the surface area of the straight body lower region 15c to be reduced increases, and in the case of 10% or more (Invention Examples 1 to 7). The raising / lowering occurrence rate is sufficiently small at 5%. And when the ratio of the reduced area was 20% or more (Invention Examples 2 and 3), no problem occurred in the lifting operation.

<Epitaxial wafer manufacturing experiment 1>
Inventive examples 2 and 3 and the lift pins of the comparative example were applied to the epitaxial growth apparatus 1 shown in FIG. 2 to manufacture an epitaxial wafer. Here, as the susceptor 4, the surface of the carbon base material with SiC coating was used. Further, a silicon wafer W having a diameter of 300 mm doped with boron was used as the substrate of the epitaxial wafer.

  In manufacturing the epitaxial wafer, first, the silicon wafer W was introduced into the epitaxial growth apparatus 1 and placed on the susceptor 4 using the lift pins 15. Subsequently, after hydrogen baking was performed at a temperature of 1150 ° C. in a hydrogen gas atmosphere, a silicon epitaxial film was grown on the surface of the silicon wafer W by 4 μm at 1150 ° C. 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. 50 epitaxial wafers were manufactured for each of the above invention examples and comparative examples.

<Evaluation of surface quality>
About the obtained epitaxial wafer, the number of the epitaxial defects formed in the epitaxial layer was evaluated. Specifically, the surface of the epitaxial layer was observed and evaluated in a DWO mode (Dark Field Wide Oblique mode: dark field / wide / oblique incidence mode) using a surface defect inspection apparatus (KLA-Tencor: Surfscan SP-2). The occurrence of LPD (Light Point Defect) having a size (diameter) of 0.25 μm or more was examined. This evaluation was performed on the wafers of Invention Examples 1 and 2 and Comparative Example, each of which was prepared 50 sheets, to determine the number of LPDs per wafer. As a result, in Invention Examples 2 and 3 in which the surface roughness of the lower portion of the straight body portion exceeds 1 μm, no sudden increase in LPD was confirmed, and it was assumed that no problems occurred in the lifting and lowering operations of the lift pins. it can. With respect to these inventive examples 2 and 3, the number of LPDs observed in all of the manufactured epitaxial wafers was 1 / wf or less.

  On the other hand, in the comparative example in which the surface roughness of the lower portion of the straight body portion is less than 1 μm, it is confirmed that a sudden increase in LPD has been confirmed, and a problem has occurred in the lifting and lowering operation of the lift pins. For these comparative examples, the number of epitaxial wafers in which the number of LPDs observed exceeded 10 / wf was two in the comparative example.

<Epitaxial wafer manufacturing experiment 2>
Like the inventive examples 2 and 3, and the comparative example, the lift pins of the inventive examples 4 to 7 were applied to the epitaxial growth apparatus 1 shown in FIG. 2 to manufacture an epitaxial wafer. Here, the production conditions are the same as those in Invention Examples 2 and 3, and Comparative Example.

  In the case of manufacturing the epitaxial wafer, in any of the inventive examples 4 to 7, in the straight body portion lower region 15c of the lift pin 15, the cross section shown in FIG. Therefore, no sudden increase in LPD was confirmed. FIG. 7 shows the relationship between the surface roughness of the upper portion of the straight body and the average number of LPDs per wafer for Invention Examples 4 to 7. From FIG. 7, the invention example 4 (surface roughness: 0.15 μm) and the invention example 5 (surface roughness: 0.3 μm) where the surface roughness of the upper region of the straight body of the lift pin is 0.3 μm or less, Inventive Example 6 (surface roughness: 0.5 μm) in which the surface roughness of the upper region of the straight body portion of the lift pin exceeds 0.3 μm while the average number of LPDs is 1 / wf or less As for Invention Example 7 (surface roughness: 1 μm), it can be seen that the average number of LPDs cannot be less than 1 / wf.

  According to the present invention, generation of wrinkles on the back surface of the epitaxial silicon wafer can be reduced, and adhesion of particles to the wafer surface can be reduced, which is useful for the semiconductor wafer manufacturing industry.

DESCRIPTION OF SYMBOLS 1,100 Epitaxial growth apparatus 2 Chamber 4 Susceptor 4h, 7h, 17h Through-hole 4s, 17s Wall surface 4w Expanded diameter part 5, 15 Lift pin 6 Lifting shaft 7 Support shaft 7a, 17a Main pillar 7b, 17b Support arm 11 Upper dome 12 Lower dome 13 Dome Mounting Body 14 Heating Lamp 15a Straight Body 15b Head 15c Straight Body Lower Area 15d Straight Body Upper Area 31 Gas Supply Port 32 Gas Discharge Port D Deficient Portion W Silicon Wafer

Claims (11)

A support shaft having a susceptor on which a silicon wafer is placed inside the chamber; a support shaft supporting the susceptor from below; a support column positioned coaxially with the center of the susceptor; and a support arm extending radially from the support column; Lift pins inserted into both of the through holes provided in the susceptor and the through holes provided in the support arm and arranged to be movable in the vertical direction. The lift pins are moved up and down to move the silicon wafer. In an epitaxial growth apparatus for desorption on a susceptor,
At least the surface area of the lift pin is made of a material having a hardness lower than that of the susceptor, and an area in contact with the support arm is provided in a lower region of the straight body portion of the lift pin that passes through the through hole of the support arm. An epitaxial growth apparatus comprising a reduced defect portion.   The epitaxial growth apparatus according to claim 1, wherein a ratio of the reduced area is 20% or more and 50% or less of the whole.   3. The epitaxial growth apparatus according to claim 1, wherein at least the surface region of the lift pin is made of glassy carbon, the susceptor is made of at least the surface region of hydrocarbon (SiC), and the support arm is made of quartz. 4.   The arithmetic average roughness of at least one of a straight barrel portion upper region of the lift pin passing through the through hole of the susceptor and a wall surface defining the through hole of the susceptor is 0.1 μm or more and 0.3 μm or less. Item 4. The epitaxial growth apparatus according to any one of Items 1 to 3.   The arithmetic average roughness of both a straight barrel portion upper region of the lift pin that passes through the through hole of the susceptor and a wall surface that defines the through hole of the susceptor is 0.1 μm or more and 0.3 μm or less. 4. The epitaxial growth apparatus according to 4.   The epitaxial growth apparatus as described in any one of Claims 1-5 by which the lower end part of the said lift pin is rounded.   An epitaxial film manufacturing method, comprising: growing an epitaxial film on a silicon wafer using the epitaxial growth apparatus according to claim 1. The silicon wafer is inserted into both a through-hole provided in a susceptor installed in an epitaxial growth apparatus for vapor-phase growth of an epitaxial layer on a silicon wafer and a through-hole provided in a support arm that supports a lower portion of the susceptor. Lift pins that are lifted and lowered while supporting the back surface of the silicon wafer when carried into the epitaxial growth apparatus or taken out from the epitaxial growth apparatus,
At least the surface layer region is made of a material having a hardness lower than that of the susceptor, and has a deficient portion that reduces an area in contact with the support arm in a lower region of the straight body portion that passes through the through hole of the support arm. A lift pin for an epitaxial growth apparatus.   The lift pin for an epitaxial growth apparatus according to claim 8, wherein at least the surface layer region is made of glassy carbon.   The lift pin for an epitaxial growth apparatus according to claim 8 or 9, wherein the surface roughness of the upper portion of the straight body portion passing through the through hole of the susceptor is 0.1 µm or more and 0.3 µm or less.   The lift pin for an epitaxial growth apparatus according to any one of claims 8 to 10, wherein a lower end portion of the lift pin is rounded.

Images