JP6047854B2 - Single wafer epitaxial wafer manufacturing apparatus and epitaxial wafer manufacturing method using the same - Google Patents

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 growing a single wafer epitaxial layer on a semiconductor wafer. In general, when an epitaxial layer is grown 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 a wafer pocket in the edge region, and the wafer pocket is formed to be several millimeters larger than the wafer. When the wafer is accommodated in the wafer pocket, the wafer can be accommodated 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. That is, it is considered that the susceptor misalignment generated at a high temperature is brought at a low temperature, which is the wafer mounting temperature, and becomes relatively eccentric when the wafer is mounted at a fixed position as it is.

  A conventional single wafer epitaxial wafer manufacturing apparatus will be described with reference to the schematic views shown in FIGS.

  A conventional single wafer epitaxial wafer manufacturing apparatus 100 shown in FIGS. 4 and 5 is provided in a chamber (not shown), and has a wafer pocket 102 (a counterbore part and a counter part) for placing the wafer W in the center of the upper surface. A support shaft 106 for supporting and rotating the susceptor 104, the support shaft 106 being rotatable main strut 108, and the main strut 108. And a plurality of arm portions 110 that support the lower surface of the susceptor 104. The susceptor 104 has a plurality of susceptor recesses 112 on the lower surface of the susceptor 104.

  The structure of the contact portion 114 of the arm portion 110 of the susceptor 104 and the support shaft 106 that supports the susceptor 104 is such that the cylindrical head portion 116 of the arm portion 110 of the support shaft 106 is in the susceptor recess 112 provided on the lower surface of the susceptor 104. The structure is inserted into the recess 112. In consideration of thermal expansion of the susceptor 104, the columnar head portion 116 of the arm portion of the support shaft 106 is a columnar SiC (silicon carbide) member 118 made of the same material as the susceptor 104, and the fitting portion is By providing a gap 122, that is, a play space that allows the thermal expansion of the susceptor 104 to escape, damage to the susceptor 104 and the cylindrical SiC member 118 is prevented. Further, the single wafer type epitaxial wafer manufacturing apparatus 100 has lift pins 124 extending through the susceptor 104, and the wafer W is moved up and down by moving the lift pins 124 up and down.

  However, when thermal expansion of the susceptor 104 occurs during heating of the chamber, the susceptor recess 112 on the lower surface of the susceptor 104 and the contact portion 114 of the arm portion cylindrical head portion 116 of the support shaft 106 slip by the gap 122. However, if thermal expansion of the susceptor is anisotropic due to the state of heat distribution, non-uniform slip occurs at each contact portion 114 of the susceptor 104 and the arm head portion 116 of the support shaft 106, As a result, there may be a displacement 126 between the center C1 of the susceptor 104 and the center C2 of the support shaft 106. This is considered to cause an eccentric placement 128 of the wafer W.

  In Patent Document 1, by changing the surface shape of the contact portion between the susceptor and the arm portion of the support shaft, even if non-uniform slippage due to susceptor thermal expansion occurs, self-alignment is performed and the susceptor is displaced. A method of preventing this is disclosed. However, the arm portion head portion of the support shaft in Patent Document 1 is formed in a columnar shape as can be seen from the figure, and is clearly in the contact portion between the recess on the lower surface of the susceptor and the arm portion head portion of the support shaft. There is a gap and there is a play space. Therefore, if the susceptor thermally expands anisotropically due to heat distribution during chamber heating, non-uniform slip occurs at each contact portion between the susceptor and the arm portion of the support shaft, resulting in the susceptor and support. There is still the possibility of misalignment between the shafts.

JP 2007-088303 A

  The present invention has been made in view of the above-described problems of the prior art, and a single wafer epitaxial wafer manufacturing apparatus capable of preventing the susceptor from being displaced during heating and manufacturing of an epitaxial wafer using the same. It aims to provide a method.

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 placing a wafer in the center of the upper surface,
A support shaft for supporting and rotating the susceptor,
The support shaft has a rotatable main column, and a plurality of arms provided on the main column and supporting the lower surface of the susceptor;
The susceptor has a plurality of susceptor recesses on a lower surface of the susceptor,
Said plurality of arm portions is a quartz head for supporting the lower surface of the susceptor vertically respectively have, in the state quartz head portion of said plurality of arm portions without play space to said plurality of susceptors recesses by being contacted with each closely fit together crimped in the width direction in a surface of said plurality of susceptors recess, and characterized in that as the thermal expansion of the susceptor can isotropically absorbed by the elastic deformation of the quartz head To do.

  In this way, slipping at the contact portion between the susceptor recess and the arm portion head of the support shaft can be eliminated by eliminating the clearance between the susceptor recess and the arm portion head of the support shaft to eliminate play. That is, at least a part of the quartz head of the arm part is closely fitted to the susceptor recess without any play space, so that the outer peripheral surface of the part is at least the inner surface in the width direction of the susceptor recess. Therefore, it is possible to eliminate slippage at the contact portion between the susceptor recess and the quartz head portion of the arm portion.

  By changing the arm portion head of the support shaft from a conventional cylindrical SiC head to a quartz head, the thermal expansion of the susceptor can be isotropically absorbed by the elastic deformation of the quartz head. Can be prevented. Further, the force acts equally on each arm portion by the repulsive force of the quartz head. Further, by changing the arm portion head of the support shaft from a conventional cylindrical SiC head to a quartz head, it is possible to prevent impurity contamination caused by metal atoms generated from the arm portion head There is also. More preferably, the arm portion including the quartz head is made of quartz.

  In addition, it is preferable that at least the quartz head of the arm portion of the support shaft has a prismatic shape. More preferably, the prismatic head is a plate-like head.

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

  According to the method for producing an epitaxial wafer of the present invention, an epitaxial wafer having a uniform epitaxial layer thickness and good flatness can be obtained by eliminating the problem of the eccentric placement of the wafer in the wafer pocket.

  According to the present invention, it is possible to provide a single-wafer epitaxial wafer manufacturing apparatus and a method for manufacturing an epitaxial wafer using the same, which can prevent the susceptor from being displaced during heating. Have

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. FIG. 2 is a detailed cross-sectional view of a susceptor-support shaft contact portion of FIG. It is a principal part enlarged view which shows the arm part head of a support shaft, Comprising: (a) shows one embodiment which made the quartz head a plate-shaped head, (b) shows the quartz head. Fig. 4 shows another embodiment in which the shape of the quartz head is made, (c) shows an embodiment in which the quartz head is shaped like a prism, and (d) shows an example in which the quartz head is made cylindrical. It is a principal part schematic diagram of the conventional single wafer type epitaxial wafer manufacturing apparatus. FIG. 5 is a detailed cross-sectional view of the susceptor-support shaft contact portion of FIG.

  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 placing a wafer W in the center of the upper surface, and a support shaft 16 for supporting and rotating the susceptor 14. The support shaft 16 includes a rotatable main column 18 and a plurality of arm portions 20 provided on the main column 18 and supporting the lower surface of the susceptor 14, and the susceptor 14 includes the susceptor 14. the lower surface 14 has a plurality of susceptor recess 22, the plurality of arm portions 20 has a quartz head 24 for supporting the lower surface of the susceptor 14 vertically, respectively, wherein the plurality of arm portions 20 closely fitted together crimped in the width direction in a surface of said plurality of susceptors recesses 22 in a state quartz head 24 of without play space the susceptor recess 22 It is contacted with 6. The single-wafer epitaxial wafer manufacturing apparatus 10 has lift pins 25 extending through the susceptor 14, and the wafer W is moved up and down by moving the lift pins 25 up and down. In the example of FIG. 1, the quartz head 24 is a plate-like head, and the center C1 of the susceptor 14 and the center C2 of the support shaft 16 are substantially coincident.

  Further, by making the head of the arm portion the quartz head 24, as shown in FIG. 2, the thermal expansion of the susceptor 14 can be isotropically absorbed by the elastic deformation of the quartz head 24, and the position of the susceptor 14 is Deviation can be prevented. In FIG. 2, the thermally expanded susceptor 14 and the elastically deformed quartz head 24 are indicated by phantom lines. Furthermore, force is applied equally to each arm portion by the repulsive force of the quartz head. Furthermore, by changing the arm portion head of the support shaft from a conventional cylindrical SiC head to a quartz head, it is possible to prevent impurity contamination due to metal atoms generated from the arm portion head. There are also advantages.

Further, as long as the quartz head 24 is closely fitted in the susceptor recess 22 without any play space and is brought into contact with the inner surface 26 in the width direction of the susceptor recess 22, the quartz head 24 can have various shapes. it can. Examples in which the quartz head has various shapes are shown in FIGS. 3, (a) shows one embodiment in which the quartz head is a plate-like head, (b) shows another embodiment in which the quartz head is a plate-like head, (C) shows an embodiment in which the quartz head has a prismatic shape, and (d) shows an example in which the quartz head has a cylindrical shape. Among these, for example, plate-like heads 28a and 28b as shown in FIGS. 3 (a) and 3 (b) are preferable. Moreover, it is good also as the prism-shaped head 30 as shown in FIG.3 (c). Furthermore, it is good also as the cylindrical head 32 as shown in FIG.3 (d).

  Hereinafter, the present invention will be described more specifically 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 a single-wafer epitaxial wafer manufacturing apparatus shown in FIG. 1 using a quartz head, P 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. Type silicon epitaxial layers (resistivity: 10 Ω · cm) were grown and evaluated based on wafer mounting deviation and EP thickness uniformity. As the quartz head, a plate-shaped head as shown in FIG. 3A was used.

<Wafer placement deviation amount>
Wafer placement deviation was evaluated by a susceptor through-hole pattern transfer method. The susceptor through-hole pattern transfer method is a method in which a wafer is placed on a susceptor having a through-hole and an etching gas is introduced at a temperature at which an epitaxial layer is grown. This is a method for measuring the position of the through-hole pattern transferred to, and evaluating the amount of eccentricity of the wafer mounting position. The amount of wafer placement deviation was 0.2 mm. The results are shown in Table 1.

<EP thickness uniformity>
The EP thickness uniformity was evaluated by the thickness difference 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 epitaxial layer at the outer peripheral portion becomes non-uniform in the circumferential direction, which causes the EP thickness uniformity to deteriorate. The difference in film thickness of the outer peripheral epitaxial layer was 42 nm. The results are shown in Table 2.

(Comparative Example 1)
Using the conventional single wafer type epitaxial wafer manufacturing apparatus shown in FIG. 4, on a P-type silicon single crystal wafer having a diameter of 300 mm and a main surface orientation (100) as in Example 1, the target thickness is 5 μm. Then, a P-type silicon epitaxial layer (resistivity: 10 Ω · cm) was grown and evaluated in the same manner as in Example 1 by the wafer mounting deviation amount and the EP thickness uniformity. The amount of wafer placement deviation was 0.6 mm. The results are shown in Table 1. Further, the outer peripheral epitaxial layer thickness difference was 65 nm. The results are shown in Table 2.

  As is clear from Tables 1 and 2, in Example 1, both the wafer placement deviation and the EP thickness uniformity were improved as compared with Comparative Example 1.

  Therefore, in the single wafer type epitaxial wafer manufacturing apparatus of the present invention in which the clearance between the recess of the susceptor and the arm portion head of the support shaft is eliminated to eliminate play, and the arm portion head of the support shaft is made of quartz, the susceptor It was confirmed that misalignment due to thermal expansion can be prevented, and wafer placement misalignment and EP thickness uniformity can be improved.

  DESCRIPTION OF SYMBOLS 10: Single wafer type epitaxial wafer manufacturing apparatus of this invention, 12, 102: Wafer pocket, 14, 104: Susceptor, 16, 106: Support shaft, 18, 108: Main strut, 20, 110: Arm part, 22, 112 : Susceptor recess, 24, 30, 32: quartz head, 25, 124: lift pin, 26: inner surface in the width direction, 28a, 28b: plate head, 100: conventional single wafer epitaxial wafer manufacturing apparatus, 114 : Contact portion, 116: cylindrical head, 118: cylindrical SiC member, 122: gap, 126: misalignment, 128: eccentric placement of wafer, C1: center of susceptor, C2: center of support shaft, W : Wafer.

Claims (4)

A susceptor provided with a wafer pocket for placing a wafer in the center of the upper surface;
A support shaft for supporting and rotating the susceptor,
The support shaft has a rotatable main column, and a plurality of arms provided on the main column and supporting the lower surface of the susceptor;
The susceptor has a plurality of susceptor recesses on a lower surface of the susceptor,
Said plurality of arm portions is a quartz head for supporting the lower surface of the susceptor vertically respectively have, in the state quartz head portion of said plurality of arm portions without play space to said plurality of susceptors recesses by being contacted with each closely fit together crimped in the width direction in a surface of said plurality of susceptors recess, and characterized in that as the thermal expansion of the susceptor can isotropically absorbed by the elastic deformation of the quartz head Single wafer epitaxial wafer manufacturing equipment.   The single-wafer epitaxial wafer manufacturing apparatus according to claim 1, wherein the arm portion of the support shaft has at least a quartz head having a prismatic shape.   The single-wafer epitaxial wafer manufacturing apparatus according to claim 2, wherein the prismatic head is a plate-like head.   An epitaxial device comprising the single wafer epitaxial wafer manufacturing apparatus according to any one of claims 1 to 3, wherein a wafer is placed in a wafer pocket of the susceptor, and an epitaxial layer is vapor-phase grown on the wafer. Wafer manufacturing method.

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