Quartz disc for improving stability of silicon epitaxy process

Abstract

The utility model discloses a quartz disc for improving the stability of a silicon epitaxy process, which comprises a disc bottom surface and a circle of side wall surrounding the outer edge of the disc bottom surface, a through hole is arranged at the center of the disc bottom surface, the side wall is connected with the disc bottom surface through a round corner, the inner wall of the side wall is perpendicular to the disc bottom surface, a circle of shielding section is arranged at the upper section of the side wall, and the shielding section is connected with the disc bottom surface. The outer wall of the shielding section inclines towards the outer side of the bottom face of the disc, and the thickness of the shielding section is gradually increased from bottom to top. According to the utility model, the shielding section is arranged, so that the problem that falling quartz slag floats upwards under the condition of direct blowing of air flow when the quartz disc has a crystallization phenomenon is avoided, and the product abnormity caused by the quartz slag problem is further reduced; meanwhile, the diameter of the quartz disc is enlarged, so that the assembly space of the graphite base is larger, the height of the side wall is reduced, and the friction phenomenon between the graphite base and the quartz disc caused by the problems of non-concentricity and poor flatness of the base in the assembly and debugging process can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of silicon epitaxial growth equipment, in particular to a quartz disc for improving the stability of a silicon epitaxial process. Background Art

[0002] Silicon epitaxy technology usually refers to the technology of growing a layer of single-crystal silicon with target thickness and resistivity on the surface of the substrate by chemical vapor deposition (CVD). In order to ensure the stable operation of the epitaxy process throughout the maintenance cycle, higher requirements are placed on the quality of spare parts and the accuracy and tolerance of assembly between spare parts. There is a higher assembly accuracy and larger adjustment tolerance between the graphite base and the quartz disc. The higher quality stability of the quartz disc is the basis for the stable operation of the entire epitaxy cycle.

[0003] like Figures 1 to 3 Schematic diagram of the cross-sectional structure of the existing graphite base and quartz disc, 1' is the quartz disc structure, 3 is the graphite base, Figure 3 The cross-sectional schematic diagram shows the case where the graphite base and the quartz disc are not assembled concentrically and the base flatness is poor. It can be seen from the figure that in the prior art, after the quartz disc and the graphite base are assembled, the single-side spacing between the two is only 4.5mm. When the graphite base and the quartz disc are assembled concentrically and the base flatness is good, there will be no friction during the rotation of the graphite base; when the two are assembled non-concentrically or the flatness of the base is adjusted in the direction of poor to match the requirements of the center value of the full furnace thickness of the epitaxial wafer, the base tilts to one side, and the rotating graphite base is prone to friction with the quartz disc, thereby generating quartz slag. At the same time, during the epitaxial cycle of the machine, raw materials will be continuously filled into the reaction chamber from the front end of the equipment, so the quartz disc will be frequently corroded by corrosive gases, causing quartz slag to fall off the side wall of the quartz disc; since the side wall of the existing quartz disc is relatively high, the fallen quartz slag is easily floated to the surface of the base under the drive of the airflow, causing abnormalities on the front and back sides of the epitaxial wafer.

[0004] Therefore, there is an urgent need to find a quartz disk that can improve the stability of the silicon epitaxial process in order to solve the above problems. Utility Model Content

[0005] Purpose of the invention: In view of the fact that the existing quartz discs are prone to cause abnormal defects on the front and back sides of epitaxial wafers due to the quartz slag that falls off and floats to the surface of the base, the utility model provides a quartz disc that improves the stability of the silicon epitaxial process.

[0006] Technical solution: To solve the above problems, the utility model adopts a quartz disc for improving the stability of the silicon epitaxial process, including a disc bottom surface and a circle of side walls surrounding the outer edge of the disc bottom surface, a through hole is provided in the center of the disc bottom surface, the side wall is connected to the disc bottom surface by a rounded corner, the inner wall of the side wall is perpendicular to the disc bottom surface, a circle of shielding sections is provided in the upper section of the side wall, the outer wall of the shielding section is inclined toward the outside of the disc bottom surface, and the thickness of the shielding section gradually increases from bottom to top.

[0007] Furthermore, the longitudinal section of the outer wall of the shielding section is a straight line, and the cross-sectional structure of the shielding section is a right-angled trapezoid.

[0008] Furthermore, the base angle of the right-angled trapezoid is 75°.

[0009] Furthermore, the thickness of the lower end of the side wall is 2 mm, and the thickness of the upper end is 3 mm.

[0010] Furthermore, the outer diameter D1 of the side wall is 655 mm, and the inner diameter D2 is 649 mm.

[0011] Furthermore, a vertical distance H between the top of the side wall and the lower end surface of the bottom surface of the disk is 15 mm.

[0012] Furthermore, the inner fillet radius R1 of the connection between the side wall and the bottom surface of the disk is 7 mm, and the outer fillet radius R2 of the connection between the side wall and the bottom surface of the disk is 10 mm.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) by setting a shielding section, the problem of quartz slag falling off when crystallization occurs on the quartz disc and floating upward under direct airflow can be avoided, thereby reducing product abnormalities caused by the quartz slag problem; (2) the diameter of the quartz disc in this embodiment is enlarged compared with the size of the existing quartz disc, the assembly space of the graphite base is larger, the spacing and height difference between the quartz disc and the graphite base after assembly are larger, and the tolerance of the quartz disc and the graphite base during assembly is improved; (3) by reducing the height of the side wall, the friction between the graphite base and the quartz disc caused by the problem of non-concentricity and poor base flatness during assembly and debugging can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a cross-sectional view of a prior art quartz disc;

[0015] Figure 2 A cross-sectional view of a prior art quartz disc and graphite susceptor assembly structure;

[0016] Figure 3 A cross-sectional view of a quartz disk and a graphite base in the prior art when they are assembled in an eccentric state;

[0017] Figure 4It is a cross-sectional view of the quartz disc of the utility model;

[0018] Figure 5 This is an enlarged schematic diagram of the structure of the quartz disc A of the utility model;

[0019] Figure 6 It is a cross-sectional view of the assembly structure of the quartz disc and graphite base of the utility model. DETAILED DESCRIPTION

[0020] like Figure 4 and Figure 5 As shown, a quartz disc for improving the stability of the silicon epitaxial process in this embodiment includes a disc bottom surface 1 and a circle of side walls 2 surrounding the outer edge of the disc bottom surface 1. A through hole is provided in the center of the disc bottom surface 1, and the side wall 2 is connected to the disc bottom surface through a fillet. The inner wall of the side wall 2 is perpendicular to the disc bottom surface 1, and a circle of shielding sections 21 is provided on the upper section of the side wall 2. The outer wall of the shielding section 21 is inclined from bottom to top toward the outer side of the disc bottom surface 1. The cross-sectional structure of the shielding section 21 is a right-angled trapezoid, and the bottom angle of the right-angled trapezoid is 75°. The thickness of the shielding section 21 gradually increases from bottom to top, and the thickness of the lower end of the side wall 2 is d=2mm, and the thickness of the upper end is 3mm. The outer diameter D1 of the side wall 2 is 655mm, and the inner diameter D2 is 649mm. The vertical distance H between the top of the side wall 2 and the lower end surface of the disc bottom surface 1 is 15mm. The inner fillet radius R1 where the side wall 2 is connected to the bottom surface 1 of the disk is 7 mm, and the outer fillet radius R2 where the side wall 2 is connected to the bottom surface 1 of the disk is 10 mm.

[0021] The utility model provides a shielding section for the quartz disc to avoid the problem of quartz slag falling off and floating upward when the airflow blows directly when crystallization occurs on the quartz disc, thereby reducing product abnormalities caused by the quartz slag problem. The diameter of the quartz disc in this embodiment is larger than the size of the existing quartz disc, and the assembly space of the graphite base 3 is larger. The spacing and height difference between the quartz disc and the graphite base 3 after assembly are larger, which improves the tolerance of the quartz disc and the graphite base 3 when assembling. At the same time, the height of the side wall 2 is reduced, which can avoid friction between the graphite base 3 and the quartz disc due to non-concentricity and poor base flatness during assembly and debugging. Figure 6 In summary, the adaptive disk of the utility model can effectively improve the stability of the silicon epitaxial process.

Claims

1. A quartz disc for improving the stability of silicon epitaxial process, comprising a disc bottom surface and a circle of side walls surrounding the outer edge of the disc bottom surface, wherein a through hole is provided at the center of the disc bottom surface, and the side wall is connected to the disc bottom surface through a fillet, characterized in that: The inner wall of the side wall is perpendicular to the bottom surface of the disk, and a circle of shielding sections is arranged on the upper section of the side wall. The outer wall of the shielding section is inclined toward the outer side of the bottom surface of the disk, and the thickness of the shielding section gradually increases from bottom to top.

2. The quartz disc for improving the stability of silicon epitaxial process according to claim 1, characterized in that: The longitudinal section of the outer wall of the shielding section is a straight line, and the cross-sectional structure of the shielding section is a right-angled trapezoid.

3. The quartz disc for improving the stability of silicon epitaxial process according to claim 2, characterized in that: The base angle of the right-angled trapezoid is 75°.

4. The quartz disc for improving the stability of silicon epitaxial process according to claim 3, characterized in that: The thickness of the lower end of the side wall is 2 mm, and the thickness of the upper end is 3 mm.

5. The quartz disc for improving the stability of silicon epitaxial process according to claim 4, characterized in that: The outer diameter D1 of the side wall is 655 mm, and the inner diameter D2 is 649 mm.

6. The quartz disc for improving the stability of silicon epitaxial process according to claim 1, characterized in that: The vertical distance H between the top of the side wall and the lower end surface of the bottom surface of the disk is 15 mm.

7. The quartz disk for improving the stability of silicon epitaxial process according to claim 1, characterized in that: The inner fillet radius R1 where the side wall is connected to the bottom surface of the disk is 7 mm, and the outer fillet radius R2 where the side wall is connected to the bottom surface of the disk is 10 mm.

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