JP2006013020A - Susceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a susceptor capable of preventing breakage at the end of cut of a wafer or inside wall of countersunk even if the wafer placed in the countersunk of the susceptor rotates or shifts. <P>SOLUTION: The susceptor is provided with a recess in which a wafer is placed for thermal treatment, with the wafer comprising a cut with a flat surface at a part of disc. A protruding part for contacting to the flat surface of the cut is formed inside the recess. The protruding part is preferred to be dogleg shape, and preferred to comprise a flat surface to contact the cut by surface as well. Further, the tip of the protruding part is preferably formed arcuately. The susceptor is preferred to be used at epitaxial growth with a wafer or surface alteration, cleaning or annealing with the wafer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a susceptor used for semiconductor manufacturing, and more particularly, to a susceptor that prevents damage to an end portion of a notch portion of a wafer and a counterbore inner wall.

Conventionally, there is a susceptor disclosed in Patent Document 1 below. In this patent document, when epitaxial growth is performed on a wafer having an orientation flat (notch) in a part of a disk, a recess having a diameter slightly larger than the diameter of the wafer provided in the susceptor (hereinafter referred to as a recess) A susceptor having an epitaxial growth auxiliary plate that is disposed on the substrate and is provided with an auxiliary plate having a shape that fills a gap formed between the orientation flat portion of the wafer and the susceptor.
Japanese Utility Model Publication No. 64-30824

  However, in Patent Document 1, when the wafer placed in the counterbore rotates or moves, the end of the orientation flat part of the wafer collides with the flat part of the auxiliary plate, and the wafer or auxiliary plate, or Both of these could be damaged.

  Accordingly, an object of the present invention is to provide a susceptor that prevents damage to the edge of the notch of the wafer and the inner wall of the counterbore even when the wafer placed in the counterbore of the susceptor rotates or moves. is there.

  The present invention provides a susceptor including a recess for placing the wafer when heat-treating a wafer including a notch having a flat surface in a part of a disk, and the notch is provided inside the recess. The convex part which contacts the flat surface of a part is formed. It is preferable that the convex part has a square shape, and it is preferable that the convex part has a flat surface that can be in surface contact with the notch part. Furthermore, it is preferable that the tip of the convex portion has an arc shape. The susceptor of the present invention is preferably used when epitaxial growth is performed on a wafer, or surface modification, surface cleaning, or annealing is performed on a wafer. The susceptor of the present invention is preferably pancake type or single wafer type.

  With the above configuration, according to the susceptor of the present invention, even if a wafer having a notch placed in the counterbore of the susceptor rotates or moves, local stress generated when the counterbore inner wall and the wafer are in contact with each other Therefore, damage to the edge of the notch of the wafer and the inner wall of the counterbore can be prevented. Further, the gap during wafer rotation can be reduced, and the gas flow can be stabilized. Furthermore, the state which ensured the clearance required when taking out a wafer from counterbore can be maintained.

  Hereinafter, a susceptor according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a pancake vertical furnace for epitaxial growth using a pancake susceptor according to an embodiment of the present invention, and FIG. 2 is a plan view showing the susceptor of FIG. 3A is an enlarged view showing a part of the susceptor of FIG. 1, and FIG. 3B shows a case where a wafer having a notch is placed in the counterbore of the susceptor of FIG. 3A. FIG. 4 is an enlarged plan view and FIG. 4 is a partial enlarged view of FIG.

  The pancake type vertical furnace 10 includes a quartz bell jar 1 capable of supplying and exhausting gas, a pancake type susceptor 2 according to this embodiment, and a high frequency induction coil 3 for heating the susceptor 2. The quartz bell jar 1 has a gas supply cylinder 5 which is a cylinder through which the center portion of the susceptor 2 penetrates at the center thereof and is rotatably supported so that gas can be supplied into the quartz bell jar 1. In addition, a plurality of exhaust ports 1a through which used gas can be exhausted are provided at the lower part of the quartz bell jar 1.

  The susceptor 2 uses a carbon-based material as a base material. High purity isotropic graphite is preferable as the carbon-based material. The smaller the impurities contained in the susceptor, the lower the quality of the epitaxially grown layer due to contamination can be prevented. Therefore, it is better that the total ash content of the susceptor is small. Usually, those having an ash content of 20 ppm or less are used. Although FIG. 2 shows the case where five counterbore 6 processed into a concave shape are provided on the upper surface of the susceptor 2, the number of counterbore is not limited to five. In FIG. 2, a gas supply cylinder 5 into which a gas for epitaxial growth or the like is introduced is provided through the center of the upper surface of the susceptor 2. The surface of the substrate is preferably covered with a SiC film or the like by a CVD method or the like. The SiC film coated by this CVD method or the like is a film formed by SiC nuclei generated from a raw material gas during a process such as CVD being deposited on the surface of the base material, and the deposited nuclei are growing. is there.

  As shown in FIG. 3A, the counterbore 6 includes a convex portion 7 formed inside at a part of the circular inner peripheral wall of the counterbore 6. As shown in FIG. 3 (b), the wafer 4 includes a notch 4 a having a flat surface in a part of the disk, and is placed inside the counterbore 6.

  As shown in FIG. 4, the convex portion 7 has a dogleg shape, and the flat portion 8 where the flat surface of the notch portion 4a of the wafer 4 comes into surface contact is formed, and the tip portion of the convex portion 7 is formed as shown in FIG. Two planes are provided symmetrically about a line passing in the vertical direction on the paper surface. Further, the tip of the convex portion 7 has an arc shape with a radius R. The size of the radius R is changed depending on the wafer used.

  Next, the operation of the susceptor 2 will be described. When the wafer 4 is placed in the counterbore 6 of the susceptor 2, the tip portion of the convex portion 7 has an arc shape with a radius R. For example, the flat portion of the notch portion 4 a of the wafer 4 and the tip portion of the convex portion 7 Even if contact is made, local stress concentration can be avoided. Further, for example, even if the wafer 4 placed in the state of FIG. 3B rotates counterclockwise, as shown in the partial enlarged view of FIG. Since the flat surface portion of the convex portion 7 is in surface contact, local stress concentration can be avoided. Although not shown, the operation is the same even if the wafer 4 rotates clockwise. In addition, since the gap between the wafer and the counterbore inner wall during wafer rotation can be reduced, the gas flow is stabilized.

  According to the susceptor 2 of the present embodiment having the above-described configuration, even when the wafer 4 having the cutout portion 4a placed in the counterbore 6 is rotated or moved, it occurs when the inner wall of the counterbore 6 and the wafer 4 are in contact with each other. Since local stress concentration can be avoided, damage to the end of the notch 4a of the wafer 4 and the inner wall of the counterbore 6 can be prevented. Further, since the gap during rotation of the wafer 4 can be reduced and the gas flow can be stabilized, an epitaxial growth layer having a uniform thickness can be formed on the wafer 4 during epitaxial growth. Further, it is possible to maintain a state in which a gap necessary for removing the wafer 4 from the counterbore 6 is secured. Further, it is suitable for performing epitaxial growth on the wafer 4 and performing surface modification, surface cleaning, or annealing on the wafer 4. Surface modification is a process of forming an oxide layer, nitride layer, etc. on the wafer surface, and surface cleaning is a process of removing contaminants adhering to the wafer surface using a mixed gas in which hydrogen chloride is diluted with hydrogen. is there. Annealing is a process that brings about an effect such as uniformly diffusing impurities in the wafer by performing a heat treatment on the wafer.

  Although not shown, as a modification of the present embodiment, the two flat portions 8 of the convex portion 7 are asymmetrical with respect to a line passing through the front end portion of the convex portion 7 in the vertical direction on the paper surface of FIG. There may be. Even in this case, since the notched portion 4a of the wafer 4 can be brought into surface contact with any of the two flat surface portions 8 of the convex portion 7, the same operation and effect as in the above embodiment can be obtained. The same applies to the following embodiments.

  Next, a susceptor according to another embodiment of the present invention will be described. The description of the same parts as those in the above embodiment will be omitted. FIG. 5 is a schematic view showing a single-wafer vertical furnace for epitaxial growth using a single-wafer susceptor according to another embodiment of the present invention, and FIG. 6 is a plan view showing the susceptor of FIG.

  The single-wafer type vertical furnace 20 includes a cylindrical quartz bell jar 11 capable of supplying and exhausting gas, a single-wafer type susceptor 12 according to the present embodiment, and a high-frequency induction coil 13 for heating the susceptor 12. It becomes. The susceptor 12 has a counterbore 16 having the same shape as the counterbore 6 of the susceptor 2 of the above embodiment, and only one wafer 14 can be placed thereon. The susceptor 12 can be freely rotated horizontally with the ground by a rotating shaft 15 attached to the lower portion thereof. An air supply port through which gas can be supplied is provided at the upper part of the quartz bell jar 11, and an exhaust port through which used gas can be exhausted is provided at the lower part of the quartz bell jar 11. The high frequency induction coil 13 is provided on the outer side near the center of the quartz bell jar 11 in the axial direction. Since the single wafer reactor can control the process well, a high-quality epitaxial growth layer with few defects can be formed on the wafer.

  According to this embodiment, the same operation and effect as the above-mentioned embodiment can be obtained.

  The susceptor of the present invention is used for semiconductor manufacturing susceptors such as a barrel susceptor and a MOCVD susceptor in addition to the pancake susceptor and single wafer susceptor described above. In particular, in a single wafer susceptor, the wafer is positioned at the center of the susceptor, and the rotational movement of the susceptor directly leads to the rotational movement of the wafer, which increases the influence of contact with the counterbore inner wall. Is the best.

  Examples of the method for producing the susceptor of the present invention include a method by cutting a substrate. The counterbore part is obtained by processing the center side of the convex part-shaped end part into a concentric circle by U-axis machining, and then machining the counterbore inner wall part into a predetermined convex part shape by an end mill.

  The present invention can be modified in design without departing from the scope of the claims, and is not limited to the above embodiment.

It is the schematic which shows the pancake type | mold vertical furnace for epitaxial growth using the pancake type susceptor which concerns on embodiment of this invention. It is a top view which shows the susceptor of FIG. (A) is an enlarged plan view showing a part of the susceptor of FIG. 2, (b) is an enlarged plan view showing a case where a wafer having a notch is placed in the counterbore of the susceptor of (a). . It is the elements on larger scale of FIG.3 (b). It is the schematic which shows the single wafer type vertical furnace for epitaxial growth using the single wafer type susceptor which concerns on embodiment of this invention. It is a top view which shows the susceptor of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Quartz bell jar 2,12 Susceptor 3,13 High frequency induction coil 4,14 Wafer 4a Notch part 5 Gas supply cylinder 6,16 Counterbore 7 Convex part 8 Plane part 10 Pancake type vertical furnace 15 Rotating shaft 20 Single wafer Vertical furnace

Claims (7)

A susceptor including a recess for placing the wafer when heat-treating a wafer including a notch having a flat surface in a part of a disk,
A susceptor in which a convex portion is formed on the inner side of the recess so as to contact the flat surface of the notch.   The susceptor according to claim 1, wherein the convex portion has a dogleg shape.   The susceptor according to claim 1, wherein the convex portion includes a flat surface that can freely come into surface contact with the notch portion.   The susceptor according to any one of claims 1 to 3, wherein a tip portion of the convex portion has an arc shape.   The susceptor according to any one of claims 1 to 4, which is used when epitaxially growing a wafer.   The susceptor according to any one of claims 1 to 4, which is used when surface modification, surface cleaning, or annealing is performed on a wafer.   The susceptor according to any one of claims 1 to 6, which is of a pancake type or a single wafer type.

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