JP2013229367A - Apparatus of manufacturing epitaxial wafer, and method of manufacturing epitaxial wafer by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus of manufacturing an epitaxial wafer capable of adjusting an inclination of a susceptor with ease, maintaining a stable height of the susceptor even at temperature rise, and manufacturing an epitaxial wafer having a good uniformity of film thickness of an epitaxial layer, and to provide a method of manufacturing an epitaxial wafer by using the same.SOLUTION: An apparatus 10 of manufacturing an epitaxial wafer comprises: a susceptor 14 provided with a wafer pocket 12 on which a wafer W is mounted; a plurality of arm parts 20a and 20b having height adjustment mechanisms 16a and 16b for the susceptor 14, and supporting at least peripheral parts 18a and 18b of the susceptor 14 via the height adjustment mechanisms 16a and 16b; and a supporting shaft 22 supporting the arm parts 20a and 20b. The height adjustment mechanisms 16a and 16b adjust an inclination of the susceptor 14 to make the susceptor 14 horizontal.

Description

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

  An epitaxial wafer manufacturing apparatus using a vapor phase growth apparatus is known as an apparatus for depositing an epitaxial layer on a semiconductor wafer in a single wafer type. In general, when an epitaxial layer is formed on a polished wafer using an 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.

  FIG. 6 shows a schematic cross-sectional view of a main part of a conventional epitaxial wafer manufacturing apparatus.

  In FIG. 6, reference numeral 200 denotes a conventional epitaxial wafer manufacturing apparatus. The epitaxial wafer manufacturing apparatus 200 includes a susceptor 204 provided with a wafer pocket 202 on which a wafer W is placed, 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.

  In recent years, miniaturization of semiconductor integrated circuits has progressed, and requirements for semiconductor wafers have become stricter and stricter, and it is desired to improve the flatness of epitaxial layers. A factor that affects the flatness of the epitaxial layer is the inclination of the susceptor on which the wafer is placed.

  In order to improve the susceptor tilt, a susceptor support mechanism that holds the susceptor with a plurality of support columns has been studied. In Patent Document 1, the susceptor tilt is changed by changing the fixed position of the central axis of the susceptor support mechanism. And eccentricity during rotation is corrected.

  However, depending on the manner of thermal deformation of the susceptor support mechanism, adjustment may be difficult, and the susceptor tilt may not be corrected. If the susceptor is tilted, the wafer slips in the wafer pocket when the wafer is placed, and there is a possibility that the wafer placement shift occurs. Further, due to the inclination of the susceptor and the accompanying wafer placement deviation, the gas may be non-uniformly applied to the wafer and the film thickness uniformity of the epitaxial layer may be deteriorated.

JP 2003-13397 A

  The present invention has been made in view of the above-described problems of the prior art. The tilt of the susceptor can be easily adjusted, and a stable susceptor height can be maintained even when the temperature is raised. An object of the present invention is to provide an epitaxial wafer manufacturing apparatus capable of manufacturing an epitaxial wafer with good thickness uniformity and an epitaxial wafer manufacturing method using the same.

  In order to solve the above-described problems, an epitaxial wafer manufacturing apparatus of the present invention includes a susceptor provided with a wafer pocket for mounting a wafer, and a height adjusting mechanism of the susceptor, through the height adjusting mechanism. An epitaxial wafer manufacturing apparatus comprising a plurality of arm portions supporting at least a peripheral portion of the susceptor and a support shaft supporting the arm portion, and adjusting the inclination of the susceptor by the height adjusting mechanism. The susceptor can be made horizontal.

  A height adjustment mechanism is provided on the arm portion of the support shaft, and at least the peripheral part of the susceptor is supported via the height adjustment mechanism, so that the susceptor can be easily tilted by the height adjustment mechanism. The susceptor can be leveled. Thereby, it is possible to prevent the wafer from being displaced due to the tilt of the susceptor.

  Further, the height adjusting mechanism can adjust the length of the arm column portion by changing the screwing of the male screw portion and the female screw portion provided in a part of the arm column portion of the arm portion. It is preferable that after the height of the susceptor is adjusted by the screwing mechanism, an external cover that prevents the screwing of the screwing mechanism from being changed is detachably provided. .

  By providing the outer cover, it is possible to change the screwing of the screwing mechanism so that the screw does not loosen and the height of the susceptor does not change due to thermal deformation or the like at the time of temperature rise during vapor phase growth of the epitaxial layer. Can be prevented.

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

  According to the present invention, the inclination of the susceptor can be easily adjusted, and a stable susceptor height can be maintained even when the temperature is raised, so that an epitaxial wafer with good epitaxial layer thickness uniformity can be manufactured. It is possible to provide an epitaxial wafer manufacturing apparatus and an epitaxial wafer manufacturing method using the same.

It is a principal part schematic sectional drawing which shows one embodiment of the epitaxial wafer manufacturing apparatus which concerns on this invention. It is a principal part expansion schematic sectional drawing which shows the state which provided the external cover so that attachment or detachment was possible in the epitaxial wafer manufacturing apparatus which concerns on this invention. It is a principal part expansion schematic perspective view which shows the state which provided the external cover so that attachment or detachment was possible in the epitaxial wafer manufacturing apparatus which concerns on this invention. It is a graph which shows the wafer position and epitaxial layer film thickness distribution in an Example. It is a graph which shows the wafer position and epitaxial layer film thickness distribution in a comparative example. It is a principal part schematic sectional drawing of the conventional epitaxial wafer manufacturing apparatus.

  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 an epitaxial wafer manufacturing apparatus according to the present invention. The epitaxial wafer manufacturing apparatus 10 includes a susceptor 14 provided with a wafer pocket 12 on which a wafer W is placed, and height adjustment mechanisms 16a and 16b of the susceptor 14 via the height adjustment mechanisms 16a and 16b. The epitaxial wafer manufacturing apparatus includes a plurality of arm portions 20a and 20b that support at least the peripheral portions 18a and 18b of the susceptor 14 and a support shaft 22 that supports the arm portions 20a and 20b. The height adjusting mechanism 16a, 16b is configured to adjust the inclination of the susceptor 14 so that the susceptor 14 can be made horizontal.

  The susceptor 14 is further provided with lift pins 24 a and 24 b for raising the wafer W from the wafer pocket 12. The peripheral portion of the wafer pocket 12 of the susceptor 14 has through holes 26a and 26b through which the lift pins 24a and 24b are inserted, and the upper ends of the lift pins 24a and 24b inserted through the through holes 26a and 26b are the wafer W. It is set as the structure made to contact | abut.

  Further, in the illustrated example, as the height adjusting mechanisms 16a and 16b, male screw portions 30a and 30b and female screw portions 32a and 32b provided in a part of the arm column portions 28a and 28b of the arm portions 20a and 20b. The example of the screwing mechanisms 34a and 34b in which the length of the arm column portions 28a and 28b can be adjusted by varying the screwing with the screw is shown. Accordingly, the height of the susceptor 14 is adjusted by adjusting the lengths of the arm column portions 28a and 28b by varying the screw engagement between the male screw portions 30a and 30b and the female screw portions 32a and 32b. The inclination of the susceptor 14 can be adjusted.

  Then, after the height of the susceptor is adjusted by the screwing mechanisms 34a and 34b, it is preferable that an external cover for preventing the screwing of the screwing mechanisms 34a and 34b is detachably provided. It is. 2 and 3 show a configuration in which the external cover is detachably provided.

  2 and 3, an external cover 36 is detachably provided in the screwing mechanisms 34a and 34b which are the height adjusting mechanisms 16a and 16b. In the illustrated example, the arm column portion 28a is a rectangular column portion, and a male external screw portion 30a and a female screw portion are provided by detachably fitting a rectangular external cover 36 to the rectangular column portion. The screwing with 32a is not changed. As a result, the length of the arm column portion 28a is fixed, and the screw engagement between the male screw portion 30a and the female screw portion 32a is loosened due to thermal deformation or the like at the time of temperature rise when the epitaxial layer is grown in a vapor phase. The height can be kept unchanged.

  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.

  On the p-type silicon single crystal wafer having a diameter of 300 mm and a main surface orientation (100) using the epitaxial wafer manufacturing apparatus of FIG. 1 in which the outer cover shown in FIGS. 2 and 3 is detachably fitted. A p-type silicon epitaxial layer (resistivity 10 Ω · cm) was grown at a target thickness of 5 μm. Then, an evaluation of the susceptor tilt before and after the susceptor tilt adjustment by the susceptor height adjustment function, an evaluation of the wafer mounting displacement amount, and an evaluation of the uniformity of the film thickness of the epitaxial layer were performed.

<Evaluation of susceptor tilt>
In the evaluation of the inclination of the susceptor, the height distribution in the circumferential direction of the susceptor was measured before and after the height adjustment, and the PV (Peak to Valley) value was calculated. With the PV value, it is possible to calculate how much the camera is inclined in which direction. The larger the PV value, the larger the inclination.

  Since the PV value before adjusting the height of the susceptor was 0.5 mm, the male screw portion and the female screw portion of the screw mechanism that is the height adjusting mechanism of the arm column portion of the susceptor are screwed to correct the inclination. When the susceptor height was adjusted after adjustment, the PV value after adjustment was improved to 0.2 mm. The evaluation after the height adjustment of the susceptor described above is taken as Example 1, and the results are shown in Table 1. The evaluation before the height adjustment of the susceptor is referred to as Comparative Example 1, and the results are shown in Table 1.

  From Table 1, it can be seen that the susceptor can be made substantially horizontal by simply adjusting the inclination of the susceptor using the height adjusting mechanism.

<Evaluation of wafer placement deviation>
In the evaluation of the wafer placement deviation amount, the wafer placement deviation amount was evaluated by a through-hole pattern transfer method before and after the height adjustment. The 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 for growing an epitaxial layer. 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.

  Since the wafer placement deviation before the height adjustment of the susceptor was 0.6 mm, the screwing of the male screw portion and the female screw portion of the screwing mechanism that is the height adjusting mechanism of the arm column portion of the susceptor was adjusted. When the height of the susceptor was adjusted, the wafer placement deviation amount was improved to 0.2 mm. The evaluation after the height adjustment of the susceptor described above is taken as Example 2, and the results are shown in Table 2. Further, the evaluation before the height adjustment of the susceptor described above is made as Comparative Example 2, and the results are shown in Table 2 and FIG.

  From Table 2, it can be seen that the wafer placement deviation amount could be improved by simply adjusting the inclination of the susceptor by the height adjustment mechanism.

<Evaluation of film thickness uniformity of epitaxial layer>
In the evaluation of the uniformity of the film thickness of the epitaxial layer, the film thickness uniformity was calculated from the cross section in an arbitrary direction excluding 2 mm from the outer periphery of the wafer. The film thickness distribution (%) of the epitaxial layer before adjusting the susceptor height was ± 1.9%, and the film thickness distribution on the left and right sides became non-uniform due to the effect of wafer placement deviation (FIG. 5). Therefore, when the height of the susceptor was adjusted by adjusting the male screw part and female screw part of the screw mechanism, which is the height adjustment mechanism of the arm pillar part of the susceptor, the film thickness distribution (%) of the epitaxial layer was adjusted. Improved to ± 0.9% (FIG. 4).

  The evaluation after the height adjustment of the susceptor described above is taken as Example 3, and the results are shown in Table 3. Further, the evaluation before the height adjustment of the susceptor described above is made as Comparative Example 3, and the results are shown in Table 3.

  From Table 3, it can be seen that an epitaxial wafer having a good film thickness uniformity of the epitaxial layer was obtained by the height adjusting mechanism.

  Further, the wafer placement deviation when the height of the susceptor in Example 2 is adjusted and the uniformity of the film thickness of the epitaxial layer when the height of the susceptor in Example 3 is adjusted. The vertical axis indicates the epitaxial layer film. FIG. 4 shows the thickness distribution and the horizontal axis as the wafer position.

  In addition, the vertical axis represents the wafer placement deviation when the height of the susceptor in Comparative Example 2 is not adjusted and the uniformity of the film thickness of the epitaxial layer when the height of the susceptor is not adjusted in Comparative Example 3. Is shown in FIG. 5 with the epitaxial layer film thickness distribution and the horizontal axis the wafer position. 4 and FIG. 5 also shows that after the height adjustment, the wafer placement deviation was improved, and an epitaxial wafer with good epitaxial layer thickness uniformity was obtained.

  Therefore, it has been confirmed that the height adjustment mechanism can improve the tilt of the susceptor and the accompanying mounting displacement in the wafer pocket, and improve the film thickness uniformity of the epitaxial layer.

  10: epitaxial wafer manufacturing apparatus of the present invention, 12, 202: wafer pocket, 14, 204: susceptor, 16a, 16b: height adjusting mechanism, 18a, 18b: peripheral portion, 20a, 20b, 206: arm portion, 22, 210: Support shaft, 24a, 24b, 208a, 208b: Lift pin, 26a, 26b, 209a, 209b: Through hole, 28a, 28b: Arm column part, 30a, 30b: Male screw part, 32a, 32b: Female screw part, 34a, 34b: screwing mechanism, 36: external cover, 200: conventional epitaxial wafer manufacturing apparatus, W: wafer.

Claims (3)

A susceptor provided with a wafer pocket for mounting a wafer;
A plurality of arm portions having a height adjusting mechanism of the susceptor and supporting at least a peripheral portion of the susceptor via the height adjusting mechanism;
A support shaft for supporting the arm part;
An epitaxial wafer manufacturing apparatus comprising:
An epitaxial wafer manufacturing apparatus characterized in that the susceptor can be made horizontal by adjusting the inclination of the susceptor by the height adjusting mechanism.   The height adjusting mechanism is a screw that is capable of adjusting the length of the arm column portion by changing the screwing of the male screw portion and the female screw portion provided in a part of the arm column portion of the arm portion. The external cover for preventing the screwing of the screwing mechanism from being changed after the height of the susceptor is adjusted by the screwing mechanism is detachably provided. 1. The epitaxial wafer manufacturing apparatus according to 1.   An epitaxial wafer manufacturing method comprising using the epitaxial wafer manufacturing apparatus according to claim 1 or 2 to level a susceptor and vapor-phase-growing an epitaxial layer on the wafer on the susceptor.

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