JP2013175543A - Single wafer type epitaxial wafer manufacturing apparatus and epitaxial wafer manufacturing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single wafer type epitaxial wafer manufacturing apparatus which prevents the misalignment of a susceptor without deteriorating the temperature distribution in a center part of the susceptor, and to provide a manufacturing method of the epitaxial wafer.SOLUTION: An single wafer type epitaxial wafer manufacturing device 10 includes: a susceptor 14 provided with a wafer pocket 12 for placing a wafer W; and a center pillar member 16 supporting a center part of the susceptor. The center pillar member 16 is formed by SiC or by applying an SiC coating to a carbon base material.

Description

  The present invention relates to a single wafer epitaxial wafer manufacturing apparatus and an epitaxial wafer manufacturing method using the same.

  2. Description of the Related Art A single wafer epitaxial wafer manufacturing apparatus using a vapor phase growth apparatus is known as an apparatus for forming a single wafer epitaxial layer on a semiconductor wafer. In general, when an epitaxial layer is formed on a polished wafer using a single wafer epitaxial wafer manufacturing apparatus, the epitaxial layer is placed on a placing portion called a susceptor and a reaction is performed.

  The susceptor has an edge region, and has a wafer pocket (sometimes called a spot facing portion) in the edge region, and the wafer pocket is formed several millimeters larger than the wafer. When the wafer is accommodated in the wafer pocket, the wafer can remain at a specific position even when the susceptor is rotated, and a homogeneous reaction is performed.

  However, when the wafer is eccentrically placed in the wafer pocket, the wafer pocket is formed several millimeters larger than the wafer as described above. Turbulent flow occurs, and the thickness of the local epitaxial layer becomes uneven, which causes deterioration of flatness.

  As one of the factors for the eccentric placement of the wafer, thermal deformation due to a rise in susceptor temperature during heating in the chamber is assumed. Due to the thermal deformation, the susceptor is displaced, and as a result, there is a possibility that the wafer is relatively eccentrically placed.

  For this reason, in the conventional single wafer epitaxial wafer manufacturing equipment, in order to suppress the eccentric placement of the wafer, a quartz column extending from the center of the support shaft to the susceptor is provided to support the susceptor, thereby suppressing the eccentric placement of the wafer. I was doing.

  FIG. 4 shows a schematic diagram of a main part of a conventional single wafer epitaxial wafer manufacturing apparatus using a central support member made of quartz.

  In FIG. 4, reference numeral 100 denotes a conventional single wafer epitaxial wafer manufacturing apparatus. The single-wafer epitaxial wafer manufacturing apparatus 100 includes a susceptor 104 provided with a wafer pocket 102 on which a wafer W is placed, and a central support member 106 that supports the central portion of the susceptor 104. The central support member 106 is made of quartz.

  The susceptor 104 is further provided with lift pins 108 a and 108 b for raising the wafer W from the wafer pocket 102. The periphery of the wafer pocket 102 of the susceptor 104 has through holes 109a and 109b through which the lift pins 108a and 108b are inserted. The upper ends of the lift pins 108a and 108b inserted through the through holes 109a and 109b are the wafer W. It is set as the structure made to contact | abut.

  The center support member 106 has a support shaft 110 attached to the lower part thereof. The support shaft 110 has an arm portion 112, and is configured to support the peripheral portion of the susceptor 104 and support the central column member 106. The center m of the susceptor 104 and the center n of the support shaft 110 coincide with each other, and the susceptor 104 is not displaced.

  However, in the single wafer type epitaxial wafer manufacturing apparatus using the above-described conventional quartz center column member, the temperature of the central portion of the susceptor 104 is lowered, and the film thickness uniformity of the epitaxial layer is deteriorated. was there.

  For this reason, in Patent Document 1, the temperature distribution is improved by removing the quartz column extending from the center of the support shaft to the susceptor.

  FIG. 5 shows a schematic diagram of a main part of a single wafer epitaxial wafer manufacturing apparatus from which a conventional central support member is removed.

  In FIG. 5, reference numeral 200 denotes a conventional single wafer epitaxial wafer manufacturing apparatus. The single wafer type epitaxial wafer manufacturing apparatus 200 includes a susceptor 204 provided with a wafer pocket 202 for placing a wafer W, and a support shaft 210 having an arm portion 206 is attached. The peripheral portion of the susceptor 204 is supported by the arm portion 206 of the support shaft 210.

  The susceptor 204 is further provided with lift pins 208 a and 208 b for raising the wafer W from the wafer pocket 202. The peripheral portion of the wafer pocket 202 of the susceptor 204 has through holes 209a and 209b through which lift pins 208a and 208b are inserted, and the upper ends of the lift pins 208a and 208b inserted through the through holes 209a and 209b are the wafer W. It is set as the structure made to contact | abut.

  However, if the quartz support extending from the center of the support shaft 210 to the susceptor 204 is removed as in the single wafer epitaxial wafer manufacturing apparatus of Patent Document 1 shown in FIG. 5, the susceptor 204 and the support shaft 210 at high temperatures are removed. Due to thermal deformation of the arm portion 206, the center O of the susceptor 204 and the center P of the support shaft 210 are displaced, and the susceptor 204 is likely to be displaced, which causes an eccentric placement of the wafer W. . Since the wafer eccentric placement induces a local non-uniform thickness of the epitaxial layer, a method for preventing the susceptor from being displaced while maintaining the temperature distribution is required.

  In recent years, the level of demand for wafer flatness has increased, and local flatness deterioration due to wafer eccentricity has become an important issue as well as the uniformity of the film thickness of the epitaxial layer.

JP 2000-103696 A

  The present invention has been made in view of the above-mentioned problems of the prior art, and is capable of preventing the susceptor from being displaced without deteriorating the temperature distribution at the center of the susceptor. An object of the present invention is to provide an apparatus and a method for manufacturing an epitaxial wafer using the same.

  In order to solve the above problems, a single wafer epitaxial wafer manufacturing apparatus according to the present invention includes a susceptor provided with a wafer pocket for mounting a wafer, and a central support member that supports the central portion of the susceptor. A single-wafer epitaxial wafer manufacturing apparatus, wherein the central support member is made of SiC (silicon carbide) or a carbon base material is coated with SiC.

  As an example of the center strut member formed by applying a SiC coating to the carbon base material, for example, a center strut member in which a SiC film is formed on a graphite base material by CVD (chemical vapor deposition) can be used.

  In this way, instead of the conventional quartz support, the support is made of SiC at the center of the susceptor or SiC coated on the carbon base, and the temperature distribution is worsened by inserting it into the center of the support shaft. Without this, it is possible to improve the susceptor misalignment.

  It is preferable that a lift pin for raising the wafer from the wafer pocket is further provided, and the center support member is made of the same material as the lift pin.

  The epitaxial wafer manufacturing method of the present invention is characterized in that the wafer is placed on the susceptor using the single wafer epitaxial wafer manufacturing apparatus, and an epitaxial layer is vapor-phase grown on the wafer.

  According to the present invention, it is possible to provide a single-wafer epitaxial wafer manufacturing apparatus capable of preventing the susceptor from being displaced without deteriorating the temperature distribution at the center of the susceptor. Has an effect.

  In addition, according to the present invention, since it is possible to prevent the susceptor from being displaced without deteriorating the temperature distribution at the center of the susceptor, an epitaxial wafer that can manufacture an epitaxial wafer having high flatness can be obtained. It has a remarkable effect that a manufacturing method can be provided.

It is a principal part schematic diagram which shows one Embodiment of the single wafer type epitaxial wafer manufacturing apparatus which concerns on this invention. 2 is a graph showing a film thickness distribution of an epitaxial layer obtained in Example 1. FIG. 6 is a graph showing the film thickness distribution of an epitaxial layer obtained in Example 2. FIG. It is the principal part schematic of the conventional single wafer type epitaxial wafer manufacturing apparatus using the center support | pillar member made from quartz. It is the principal part schematic of the single wafer type epitaxial wafer manufacturing apparatus which removed the conventional center support | pillar member. 6 is a graph showing a film thickness distribution of an epitaxial layer obtained in Comparative Example 1. 6 is a graph showing a film thickness distribution of an epitaxial layer obtained in Comparative Example 2.

  In the following, one embodiment of the present invention will be described with reference to the accompanying drawings. However, it is needless to say that these descriptions are given by way of example and should not be construed as limiting.

  In FIG. 1, reference numeral 10 denotes one embodiment of a single wafer epitaxial wafer manufacturing apparatus according to the present invention. The single wafer epitaxial wafer manufacturing apparatus 10 includes a susceptor 14 provided with a wafer pocket 12 for mounting a wafer W, and a central support member 16 that supports the central portion of the susceptor 14. In the wafer manufacturing apparatus, the central support member 16 is made of SiC or formed by applying a SiC coating to a carbon base material.

  The susceptor 14 is further provided with lift pins 18 a and 18 b for raising the wafer W from the wafer pocket 12. That is, as shown in FIG. 1, the peripheral portion of the wafer pocket 12 of the susceptor 14 has through holes 19a and 19b through which the lift pins 18a and 18b are inserted, and the through holes 19a and 19b are inserted. It is preferable that the upper ends of the lift pins 18a and 18b be in contact with the wafer W. The configuration of the lift pins 18a and 18b can be the same as the lift pin described in Patent Document 1, for example. The lift pins 18a and 18b are preferably made of the same material as that of the central support member 16.

  A support shaft 20 is attached to the lower portion of the central support member 16. The support shaft 20 has an arm portion 22, and is configured to support the peripheral portion of the susceptor 14 and the center support member 16. The central support member 16 has an annular fixing jig 24, and the central support member 16 is fixed to the susceptor 14 by the fixing jig 24.

  Preferably, as shown in FIG. 1, the center of the susceptor 14 has a through hole 26 through which the central column member 16 is inserted, and an upper end of the central column member 16 inserted through the through hole 26. It is preferable to adopt a configuration in which the wafer W is brought into contact with the wafer W.

  Therefore, the center Q of the susceptor 14 and the center R of the support shaft 20 coincide with each other, and the susceptor 14 is not displaced.

  In this way, instead of the conventional quartz support, the support is made of SiC at the center of the susceptor or SiC coated on the carbon base, and the temperature distribution is worsened by inserting it into the center of the support shaft. Without this, it is possible to improve the susceptor misalignment.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples, and various modifications can be made without departing from the technical idea of the present invention. Of course.

Example 1
Using the single wafer epitaxial wafer manufacturing apparatus shown in FIG. 1, a p-type silicon epitaxial layer (resistivity) is formed on a p-type silicon single crystal wafer having a diameter of 300 mm and a main surface orientation (100) at a target thickness of 5 μm. 10 Ω · cm). The lift pins 18a and 18b and the central support member 16 are made of SiC (silicon carbide).

  The temperature distribution as an evaluation item was evaluated by the film thickness of the epitaxial layer. When the temperature at the central portion is lowered, the film thickness is also reduced and the film thickness is reduced. Therefore, the temperature can be evaluated by the film thickness distribution of the epitaxial layer at the central portion. Further, the wafer placement deviation was evaluated based on the difference in film thickness of the outer peripheral epitaxial layer 2 mm from the outer peripheral edge of the wafer. It has been found that when the wafer is displaced, the thickness of the outer peripheral epitaxial layer becomes uneven in the circumferential direction, which causes the flatness to deteriorate. Therefore, by evaluating the film thickness difference of the epitaxial layer in the circumferential direction of the outer peripheral portion of the wafer, it was evaluated whether or not the wafer placement deviation occurred.

  The results are shown in FIG. As shown in FIG. 2, since the thinning of the central portion did not occur, the epitaxial wafer having a good flatness with small variations in the thickness distribution (%) of the epitaxial layer at any wafer position (wafer position). was gotten. Therefore, it can be determined that the temperature drop at the center of the susceptor 14 did not occur. Further, the outer peripheral epitaxial layer thickness difference is 39.8 nm, which is the same value as in Comparative Example 1 in which the conventional quartz center column member exists, and it is determined that the susceptor 14 is not displaced by the SiC center column member 16. it can. Therefore, good results were obtained.

(Example 2)
As a central strut member, on a p-type silicon single crystal wafer having a diameter of 300 mm and a main surface plane orientation (100) in the same manner as in Example 1 except that the carbon base material is coated with SiC to form a central strut member. A p-type silicon epitaxial layer (resistivity 10 Ω · cm) was grown at a target thickness of 5 μm. The center strut member in which the SiC substrate was coated with a SiC substrate was obtained by forming a SiC film on the graphite substrate by CVD (Chemical Vapor Deposition) and using it as a center strut member.

  The results evaluated in the same manner as in Example 1 are shown in FIG. As shown in FIG. 3, since the central portion was not thinned, an epitaxial wafer having a good flatness with a small variation in the thickness distribution (%) of the epitaxial layer at any wafer position (wafer position). was gotten. Therefore, it can be determined that the temperature did not drop at the center of the susceptor. In addition, the outer peripheral epitaxial layer thickness difference is 40.3 nm, which is the same value as in Comparative Example 1 where a conventional quartz center column member exists, and the susceptor misalignment is caused by the center column member in which the SiC substrate is coated with SiC. It can be judged that it did not happen. Therefore, good results were obtained.

(Comparative Example 1)
As Comparative Example 1, the epitaxial growth was performed under the same conditions as in Example 1 except that the single-wafer epitaxial wafer manufacturing apparatus 100 using the support shaft 110 having the conventional central support member 106 made of quartz shown in FIG. A wafer manufacturing test was conducted. The results are shown in FIG.

  As shown in FIG. 6, the thickness of the epitaxial layer at the center is reduced by about 1.3%, and the uniformity of the thickness of the epitaxial layer at the center has deteriorated. Therefore, in the support shaft 110 having this quartz center column 106, It can be determined by the center support 106 that a temperature drop in the center has occurred. On the other hand, since the thickness difference of the outer peripheral epitaxial layer was as good as 41.7 nm, the susceptor displacement did not occur due to the central support column, and as a result, the wafer mounting displacement did not occur.

(Comparative Example 2)
As Comparative Example 2, an epitaxial wafer manufacturing test was performed under the same conditions as in Example 1 except that the single wafer type epitaxial wafer manufacturing apparatus 200 from which the conventional central support member shown in FIG. 5 was removed was used. The results are shown in FIG.

  As shown in FIG. 6, the thinning of the central portion did not occur, and the temperature of the central portion of the susceptor 204 did not decrease in the support shaft 210 without the central support column. On the other hand, the difference in film thickness of the outer peripheral epitaxial layer deteriorated to 68.3 nm, and it seems that the wafer was displaced due to the removal of the central column.

  Table 2 shows the evaluation of the epitaxial wafer obtained as described above.

  As can be seen from Table 2, in Example 1 and Example 2, since the wafer placement deviation could be improved while maintaining the temperature distribution in the central part, the total epitaxial layer film thickness distribution and the outer peripheral epitaxial film thickness Good results were obtained in both distributions. As described above, according to the present invention, since the position shift of the susceptor can be prevented without deteriorating the temperature distribution at the center of the susceptor, an epitaxial wafer having a good flatness can be manufactured.

  10: Single wafer type epitaxial wafer manufacturing apparatus of the present invention, 12, 102, 202: Wafer pocket, 14, 104, 204: Susceptor, 16, 106: Central support member, 18a, 18b, 108a, 108b, 208a, 208b, 209a, 209b: lift pins, 19a, 19b, 109a, 109b: through holes, 20, 110, 210: support shafts, 22, 112, 206: arm portions, 24: fixing jigs, 26: through holes, 100, 200: Conventional single wafer epitaxial wafer manufacturing apparatus, m, O, Q: center of susceptor, n, P, R: center of support shaft, W: wafer.

Claims (3)

  A single wafer epitaxial wafer manufacturing apparatus having a susceptor provided with a wafer pocket for placing a wafer, and a central support member supporting a central portion of the susceptor, wherein the central support member is made of SiC. A single wafer type epitaxial wafer manufacturing apparatus comprising a carbon base material or a SiC coating.   2. The single wafer epitaxial wafer manufacturing apparatus according to claim 1, further comprising lift pins for raising the wafer from the wafer pocket, wherein the central support member is made of the same material as the lift pins.   An epitaxial wafer manufacturing method, comprising: using the single wafer epitaxial wafer manufacturing apparatus according to claim 1 or 2; placing a wafer on the susceptor and vapor-phase growing an epitaxial layer on the wafer.

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