Base support structure and epitaxial growth device

Abstract

The present invention relates to a pedestal support structure for supporting a pedestal in an epitaxial growth apparatus. The pedestal support structure includes a main support shaft and a plurality of support arms extending outward from the main support shaft, and the support arms have a patterned hollow structure. The present invention also relates to an epitaxial growth apparatus. By providing the hollow structure, the area of the region where the pedestal is blocked by the support arms is reduced, the heat uniformity on the back surface of the pedestal is improved, and the thickness and resistivity uniformity of the wafer are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of epitaxial growth, and particularly relates to a pedestal support structure and an epitaxial growth apparatus. Background Art

[0002] The epitaxial growth process of silicon is an important process in semiconductor chip manufacturing. It uses the CVD (Chemical Vapor Deposition) method to epitaxially grow a single-crystal silicon epitaxial layer on a polished wafer substrate, with parameters such as thickness, resistivity, doping type, and lattice structure all meeting specific requirements. Its reaction mechanism is that in a certain high-temperature environment, silicon atoms are generated by the reaction of silicon source gas and hydrogen and deposited on the surface of the silicon wafer to form an epitaxial layer, and different dopants (B 2 H 6 or PH 3 ) are introduced during the same period to dope the epitaxial layer to obtain a specific resistivity.

[0003] Generally, an epitaxial growth apparatus includes an upper quartz bell jar, a lower quartz bell jar, an air inlet, an air outlet, and a mounting component. The internal structure includes a pedestal for placing silicon wafers, a pedestal support rod, and a wafer support rod. Among them, the pedestal support rod plays the role of fixing the pedestal and driving the pedestal to rotate, so that the wafer can be evenly heated on the pedestal. A heating lamp is fixedly arranged at a fixed position outside the quartz bell jar to provide heat for the chemical vapor deposition reaction through thermal radiation.

[0004] The main function of the pedestal support rod is to fix the pedestal and drive the pedestal and the wafer above it to rotate. However, since it is a solid quartz structure, the heating light source emitted by the external heating lamp has to pass through a layer of quartz bell jar first and then through the pedestal support rod before it can irradiate the bottom of the pedestal, which will cause uneven heating of the area of the pedestal bottom blocked by the support rod, thereby affecting the temperature of the corresponding position of the silicon wafer grown above. Since the epitaxial layer growth rate is positively correlated with temperature, it will also lead to uneven epitaxial growth thickness and resistivity, easily form abnormal patterns, and have a great impact on the yield. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a pedestal support structure and an epitaxial growth apparatus, which solve the problem of uneven heating of the pedestal caused by the blockage of the pedestal support rod, resulting in uneven epitaxial growth thickness and resistivity.

[0006] To achieve the above object, the technical solution adopted in the embodiment of the present invention is: a pedestal support structure for supporting a pedestal in an epitaxial growth apparatus, the pedestal support structure including a main support shaft, and a plurality of support arms extending outward from the main support shaft, and the support arms having a patterned hollow structure.

[0007] Optionally, along the extending direction of the support arm, a hollow structure is provided on a first region of the support arm, and the length of the first region in the extending direction of the support arm is less than or equal to the length of the corresponding support arm.

[0008] Optionally, along the axial direction of the main support shaft, the support arm includes opposite first and second surfaces, and the hollow structure is provided through the first and second surfaces.

[0009] Optionally, along a first direction perpendicular to the axial direction of the main support shaft, the support arm includes opposite third and fourth surfaces, and the hollow structure is provided through the third and fourth surfaces.

[0010] Optionally, the shape of the hollow structure is a plurality of equilateral triangles arranged along the extending direction of the support arm.

[0011] Optionally, along the direction away from the support shaft, the width of the support arm gradually decreases in a first direction perpendicular to the extending direction of the support arm.

[0012] Optionally, a second solid region is included on the support arm, and a through hole is provided on the second region, and the axial direction of the through hole is parallel to the axial direction of the main support shaft.

[0013] An embodiment of the present invention further provides an epitaxial growth device, including:

[0014] A reaction chamber formed by enclosing with two relatively arranged quartz bell jars;

[0015] A base, located in the reaction chamber, for carrying a silicon wafer;

[0016] A heating structure for providing heat to the reaction chamber;

[0017] And the above-mentioned base support structure.

[0018] Optionally, a second solid region is included on the support arm, and a through hole is provided on the second region, and the extending direction of the through hole is parallel to the axial direction of the main support shaft;

[0019] A support fixing rod is provided between the base and the support arm, and the support fixing rod is connected to the support arm through the through hole.

[0020] Optionally, a base lifting structure is further included, and the base lifting structure includes:

[0021] A lifting shaft provided outside the main support shaft;

[0022] A plurality of lifting arms are arranged at one end of the lifting shaft. The lifting arms extend outward from the lifting shaft in the radial direction thereof and extend in a direction close to the base.

[0023] A lifting pin, one end of the lifting pin is fixed to one side of the base facing the main support shaft, the other end of the lifting pin passes through a through hole on the support arm and is exposed outside the support arm, and the orthographic projection of the lifting pin in the axial direction of the lifting shaft is located at one end of the lifting arm away from the lifting shaft.

[0024] The beneficial effect of the present invention is that through the arrangement of the hollow structure, the area of the region where the base is blocked by the support arm is reduced, so that the heat on the back surface of the base is more uniform, and the thickness and resistivity uniformity of the wafer are improved. Description of the Drawings

[0025] Figure 1 A schematic diagram showing an epitaxial growth apparatus in the related art;

[0026] Figure 2 A schematic diagram showing a base support structure in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram showing a support arm in an embodiment of the present invention. Detailed Embodiments

[0028] In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0030] Refer to Figure 1, in the related art, an epitaxial growth apparatus includes an upper quartz bell jar 1, a lower quartz bell jar 2, an air inlet, an air outlet, and a mounting member. The internal structure includes a base 8 for placing a silicon wafer and a base support structure. Among them, the base support structure plays a role in fixing the base 8 and driving the base 8 to rotate, so that the wafer can be evenly heated on the base 8. A heating lamp 3 is fixedly arranged at an external fixed position of the quartz bell jar, and provides heat for the chemical vapor deposition reaction by means of thermal radiation. The base support structure includes a main support shaft 4 and a plurality of support arms 10 extending outward from the main support shaft 4. Both the support shaft and the support arms 10 are solidly arranged, which will block the transfer of heat. The heating light source emitted by the external heating lamp has to pass through a layer of quartz bell jar first, and then pass through the base support rod before it can irradiate the bottom of the base 8, which will cause the area of the bottom of the base 8 blocked by the support rod to be unevenly heated, thereby affecting the temperature of the corresponding position of the silicon wafer grown above. Since the epitaxial layer growth rate is positively correlated with the temperature, it will also cause the epitaxial growth thickness and resistivity to be uneven, and abnormal patterns are easily formed, which has a great impact on the yield.

[0031] Reference Figures 1 - 3 , this embodiment provides a base support structure for supporting the base 8 in the epitaxial growth apparatus. The base support structure includes a main support shaft 4 and a plurality of support arms 10 extending outward from the main support shaft 4. The support arms 10 have a patterned hollow structure 101.

[0032] A patterned hollow structure 101 is arranged on the support arm 10 to improve the light transmittance of the support arm 10, so that the radiation heat provided by the heating lamp 3 below is more uniform in the temperature field formed between the part blocked by the support arm 10 and other areas, optimizing the distribution of the heating power on the back of the base 8 and improving the uniformity of the thickness and resistivity of the wafer.

[0033] The arrangement of the hollow structure 101 makes the center of gravity of the base support structure move downward, which can improve the offset of the base 8 caused by the rotation of the base support structure driving the base 8.

[0034] In an exemplary embodiment, along the extending direction of the support arm 10, the hollow structure 101 is arranged on the first region 1001 of the support arm 10, and the length of the first region 1001 in the extending direction of the support arm 10 is less than or equal to the length of the corresponding support arm 10.

[0035] Specific parameters such as the specific position and size of the hollow structure 101 can be set according to actual needs. It can be such that the entire support arm 10 is provided with the hollow structure 101, or it can be such that a part of the support arm 10 is provided with the hollow structure 101, as long as the light transmittance of the support arm 10 can be increased.

[0036] In an exemplary embodiment, along the axial direction of the main support shaft 4, the support arm 10 includes opposite first and second surfaces, and the hollow structure 101 penetrates through the first and second surfaces.

[0037] In an epitaxial growth apparatus, a heating lamp 3 is provided on a side of the lower quartz bell jar 2 away from the upper quartz bell jar 1, and a heating lamp 3 is provided on a side of the upper quartz bell jar 1 away from the lower quartz bell jar 2. Most of the light emitted by the heating lamp 3 located on the side of the lower quartz bell jar 2 away from the upper quartz bell jar 1 is emitted in a direction perpendicular to the base 8. Thus, by simply providing the hollow structure 101 that penetrates the support arm 10 between the first and second surfaces, the temperature difference between the area blocked by the support arm 10 on the base 8 and other areas can be reduced, and the support stability of the support arm 10 can be ensured.

[0038] In an exemplary embodiment, along a first direction perpendicular to the axial direction of the main support shaft 4, the support arm 10 includes opposite third and fourth surfaces, and the hollow structure 101 penetrates through the third and fourth surfaces.

[0039] The base support structure is used to support the base 8 and drive the base 8 to rotate. In order to effectively increase the light transmittance of the support arm 10 and further reduce the temperature difference between the area blocked by the support arm 10 on the base 8 and other areas, the hollow structure 101 that penetrates the support arm 10 is provided between the third and fourth surfaces.

[0040] Exemplarily, the hollow structure 101 that penetrates the support arm 10 is provided between any two opposite surfaces in any direction perpendicular to the extending direction of the support arm 10 to maximize the light transmittance of the support arm 10.

[0041] Exemplarily, in a direction perpendicular to the extending direction of the support arm 10, the shape of the hollow structure 101 is a plurality of equilateral triangles arranged along the extending direction of the support arm 10.

[0042] The setting of the equilateral triangle pattern enhances the strength of the support arm 10 and improves the support stability of the base 8.

[0043] Exemplarily, the equilateral triangle includes a first vertex and a base opposite to the first vertex. The first vertex of the equilateral triangle is located on the first surface, the base of the equilateral triangle is located on the second surface, and the bases of adjacent two triangles are connected.

[0044] Exemplarily, along a direction perpendicular to the extension direction of the support arm 10, the support arm 10 includes a first part 100 and a second part 200. Along the extension direction of the support arm 10, a plurality of equilateral triangle pattern structures are distributed on both the first part 100 and the second part 200.

[0045] The equilateral triangle pattern structures on the first part 100 and the equilateral triangle pattern structures on the second part 200 are arranged in an interleaved manner.

[0046] The first vertex of an equilateral triangle pattern on the first part 100 is located at the midpoint of the base of the corresponding equilateral triangle pattern on the second part 200.

[0047] The base of the equilateral triangle pattern on the first part 100 is disposed close to the second part 200, and the first vertex of the equilateral triangle pattern on the second part 200 is disposed close to the first part 100.

[0048] In an exemplary embodiment, along a direction away from the main support shaft 4, the width of the support arm 10 gradually decreases in a first direction perpendicular to the extension direction of the support arm 10. This can reduce the area of the base 8 blocked by the support arm 10, thereby improving the uniformity of epitaxial growth.

[0049] In an exemplary embodiment, the support arm 10 includes a second region 1002 that is solidly provided. A through hole 102 is provided on the second region 1002, and the extension direction (i.e., the axial direction) of the through hole 102 is parallel to the axial direction of the main support shaft 4.

[0050] The through hole 102 is provided for connecting the support rod of the support base 8 and the lifting pin 5 for supporting the silicon wafer. The through hole 102 is provided in the solidly provided second region 1002, which can improve the connection stability.

[0051] Exemplarily, the width of the support arm 10 in the first direction is 7.9 - 8.1 mm, and the first direction is perpendicular to the extension direction of the support arm 10.

[0052] Exemplarily, the height of the support arm 10 is 11.3 - 11.6 mm, and the length of the support arm 10 in its extension direction is 149.8 - 150.2 mm.

[0053] It should be noted that the support arm 10 includes a first end connected to the main support shaft 4 and a second end opposite to the first end. In the axial direction of the main support shaft 4, the distance between the first end and the second end is the height of the support arm 10.

[0054] Exemplarily, the base support structure includes three of the support arms 10, and the angle between two adjacent support arms 10 is 120 degrees.

[0055] Exemplarily, the support arm 10 is made of quartz material.

[0056] An embodiment of the present invention further provides an epitaxial growth apparatus, including:

[0057] A reaction chamber formed by enclosing with two relatively arranged quartz bell jars;

[0058] A base 8, located inside the reaction chamber, for carrying silicon wafers;

[0059] A heating structure for providing heat to the reaction chamber;

[0060] And the above-mentioned base support structure.

[0061] In an exemplary embodiment, the support arm 10 includes a solid second region 1002, and a through hole 102 is provided on the second region 1002, and the extending direction of the through hole 102 is parallel to the axial direction of the main support shaft 4;

[0062] A support fixing rod is provided between the base 8 and the support arm 10, and the support fixing rod is connected to the support arm 10 through the through hole 102.

[0063] The setting of the solid region can enhance the strength of the support arm 10 to improve the connection stability between the support arm 10 and the support fixing rod.

[0064] In an exemplary embodiment, the epitaxial growth apparatus further includes a base 8 lifting structure, and the base 8 lifting structure includes:

[0065] A lifting shaft 7 provided outside the main support shaft 4;

[0066] A plurality of lifting arms 6 provided at one end of the lifting shaft 7, and the lifting arms 6 extend outward along the radial direction of the lifting shaft 7 and extend in the direction close to the base 8;

[0067] A lifting pin 5, one end of the lifting pin 5 is fixed to the side of the base 8 facing the main support shaft 4, the other end of the lifting pin 5 passes through the through hole 102 on the support arm 10 and is exposed outside the support arm 10, and the positive projection of the lifting pin 5 in the axial direction of the lifting shaft is located at the end of the lifting arm 6 away from the lifting shaft 7.

[0068] A plurality of lifting pins 5 correspond to the plurality of support arms 10 one by one. Each of the lifting pins 5 is disposed through a through hole 102 on the corresponding support arm 10. A groove is provided at one end of the lifting arm 6 away from the lifting shaft 7. An insertion portion capable of being inserted into the groove is provided at one end of the lifting pin 5 away from the base 8. The lifting shaft 7 moves in a direction close to the base 8, thereby driving the lifting pin 5 to rise, realizing the rise of the silicon wafer carried on the base 8.

[0069] A heating structure is further provided outside the quartz bell jar. The heating structure can be a plurality of heating lamps 3 to provide heat.

[0070] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A pedestal support structure for supporting a pedestal in an epitaxial growth apparatus, the pedestal support structure comprising a main support shaft and a plurality of support arms extending outward from the main support shaft. Characterized in that, The support arm has a patterned hollow structure; Along the direction away from the main support shaft, the width of the support arm gradually decreases in a first direction perpendicular to the extension direction of the support arm.

2. The pedestal support structure according to claim 1, Characterized in that, Along the extension direction of the support arm, the hollow structure is provided in a first region of the support arm, and the length of the first region in the extension direction of the support arm is less than or equal to the length of the corresponding support arm.

3. The pedestal support structure according to claim 1, Characterized in that, Along the axial direction of the main support shaft, the support arm includes opposite first and second surfaces, and the hollow structure is provided through the first and second surfaces.

4. The pedestal support structure according to claim 3, Characterized in that, Along a first direction perpendicular to the axial direction of the main support shaft, the support arm includes opposite third and fourth surfaces, and the hollow structure is provided through the third and fourth surfaces.

5. The pedestal support structure according to claim 1, Characterized in that, The shape of the hollow structure is a plurality of equilateral triangles arranged along the extension direction of the support arm.

6. The pedestal support structure according to claim 1, Characterized in that, The support arm includes a second region provided in a solid state, and a through hole is provided in the second region, and the axial direction of the through hole is parallel to the axial direction of the main support shaft.

7. An epitaxial growth apparatus, Characterized in that, Comprising: A reaction chamber formed by enclosing two relatively arranged quartz bell jars; A pedestal located in the reaction chamber for carrying a silicon wafer; A heating structure for providing heat to the reaction chamber; And the pedestal support structure according to any one of claims 1-6.

8. The epitaxial growth apparatus according to claim 7, Characterized in that, The support arm includes a second region provided in a solid state, and a through hole is provided in the second region, and the extension direction of the through hole is parallel to the axial direction of the main support shaft; A support fixing rod is provided between the pedestal and the support arm, and the support fixing rod is connected to the support arm through the through hole.

9. The epitaxial growth apparatus according to claim 7, Characterized in that, It further includes a pedestal lifting structure, and the pedestal lifting structure includes: A lifting shaft provided outside the main support shaft; A plurality of lifting arms provided at one end of the lifting shaft, the lifting arms extending outward from the lifting shaft in a radial direction thereof and extending in a direction close to the pedestal; A lifting pin, one end of the lifting pin is fixed to the side of the pedestal facing the main support shaft, the other end of the lifting pin passes through the through hole on the support arm and is exposed outside the support arm, and the positive projection of the lifting pin in the axial direction of the lifting shaft is located at the end of the lifting arm away from the lifting shaft.

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