Susceptor for epitaxial growth and epitaxial growth apparatus including the same

Abstract

A substrate for epitaxial growth is provided, which enables the formation of a thin film of uniform thickness by temperature homogenization above a wafer, and an epitaxial growth apparatus comprising the substrate. The substrate for the epitaxial growth apparatus includes: a body having a groove on its top surface in which a wafer is placed; and a temperature control plate placed in the groove and having a plate shape, wherein the wafer is supported on its top surface. The temperature control plate has a plurality of recesses.

Description

Technical Field

[0001] Cross-reference to related applications: This application claims priority to Korean Patent Application No. 10-2024-0024144 (filed on February 20, 2024) pursuant to 35 USC 119 and 35 USC 365, the entire contents of which are incorporated herein by reference.

[0002] This disclosure relates to a substrate for epitaxial growth that enables the formation of a thin film of uniform thickness by temperature homogenization above a wafer, and an epitaxial growth apparatus comprising the substrate. Prior Technology

[0003] Generally speaking, wafers, which are widely used as materials for manufacturing semiconductor devices, refer to single-crystal silicon sheets made from polycrystalline silicon, as well as sapphire substrates, composite substrates, and SiC substrates.

[0004] Monocrystalline silicon wafers can be formed through a slicing process that grows polycrystalline silicon into monocrystalline silicon ingots and then slices the ingots into wafers, a grinding process that homogenizes the thickness of the wafers to form flat wafers, an etching process that removes or reduces damage caused by subsequent polishing, a polishing process that polishes the surface of the wafers, and a cleaning process that cleans the wafers.

[0005] In addition, many epitaxial wafers are manufactured by growing another single-crystal film (i.e., an epitaxial layer) on the polished surface of the wafer. The epitaxial layer has high purity and excellent crystal properties, and therefore, each epitaxial wafer can have the advantage of improved yield and device characteristics in increasingly integrated semiconductor devices.

[0006] Referring to the process of depositing an epitaxial layer on the surface of a wafer, a silicon wafer is mounted on a single pedestal horizontally placed in a processing chamber, and a heat source such as infrared lamps placed around the wafer is used to raise the wafer to a high temperature. Then, while the pedestal is rotated, a reactive gas is allowed to flow over the surface of the wafer at a high temperature, thereby initiating epitaxial growth on the surface of the wafer.

[0007] As wafer diameters have increased in recent years, fluid flow within the processing chamber and the shape of the substrate have become important in order to uniformly form epitaxial layers up to the edge of the wafer.

[0008] Figure 1 is a side view of the support structure of the substrate used for epitaxial growth according to the related technology. Figure 2 is a graph showing the change of film thickness with film growth temperature during the epitaxial growth process according to the related technology. Figure 3 is a graph showing the change of film thickness within the wafer radius during the epitaxial growth process according to the related technology.

[0009] According to relevant technology, as shown in Figure 1, the following can be provided: a base 11 on which the silicon wafer is placed; a rotating shaft 12 disposed below the base 11; and a support 13 mounted on the upper end of the rotating shaft 12 to support the base 11.

[0010] The base 11 may be provided with a groove (not shown) in which the wafer is placed and can rotate while being supported by the support member 13. When the reactive gas flows over the base 11, a thin film can be grown on the top surface of the wafer placed on the base 11.

[0011] As the epitaxial growth process proceeds, as shown in Figure 2, the higher the temperature at the top of the wafer, the thicker the film formed.

[0012] However, the wafer with a diameter of approximately 150 mm or more was divided into four radial regions, and the thickness variation of the thin film within the wafer radius was measured during the epitaxial growth process. As shown in Figure 3, the thickness deviation of the thin film within the wafer radius was approximately 0.4 μm, and the thickness of the thin film increased from the center of the wafer towards the first to third regions, and then the thickness of the thin film rapidly decreased in the fourth region.

[0013] Considering the film thickness formed according to the relevant technology, since the thickness in the first region is less than that in the third region, it is evident that the temperature in the first region is lower than that in the third region. Therefore, it is clear that the film formation temperature is unbalanced between the first and fourth regions.

[0014] According to Japanese Patent Publication No. 2007-294942 (filed on March 30, 2007), this document relates to an apparatus for manufacturing epitaxial wafers, which controls the thickness of an epitaxial layer on the outer peripheral portion of the wafer. The apparatus may be provided with an opening in a recess into which a semiconductor wafer is placed, may include a base for fixing the semiconductor wafer, may be provided with orientation-dependent control means depending on the crystal orientation of the semiconductor wafer and / or orientation-independent control means not depending on the crystal orientation of the semiconductor wafer, and may improve the flatness of the peripheral portion of the semiconductor wafer.

[0015] According to the above technology, the structure and shape of the substrate can be periodically changed according to the changes in the crystal orientation of the wafer to control the thickness of the thin film. However, manufacturing the substrate is difficult, and the effect is insufficient when the thickness deviation of the thin film is large.

[0016] According to Korean Patent Publication No. 2019-0100365 (priority application date: March 7, 2017), this document relates to an epitaxial growth apparatus for improving the thickness uniformity of an epitaxial layer. The epitaxial growth apparatus may be provided with a base 20 and a preheating ring 60 covering the side surface of the base 20 and having a gap therebetween. Here, a gap width is defined in at least a portion between the base 20 and the preheating ring 60, which is wider than the gap width W1 between the base 20 and the preheating ring 60 on one side of the reaction gas supply port.

[0017] According to the above technology, the temperature of the reactant gas can be controlled by controlling the gap width between the base and the preheating ring, and the thickness of the film can be controlled based on the temperature of the reactant gas. However, its limitation is that it is difficult to precisely control the temperature of the flowing reactant gas, and therefore, it is impossible to precisely control the thickness of the film. Summary of the Invention

[0018] The purpose of these embodiments is to overcome the above-mentioned limitations and other limitations.

[0019] Various embodiments also provide a substrate for epitaxial growth, which can form a thin film of uniform thickness by temperature homogenization above the wafer, and an epitaxial growth apparatus including the substrate.

[0020] In one embodiment, the base for the epitaxial growth apparatus includes: a body having a groove on its top surface, in which a wafer is placed; and a temperature control plate placed in the groove and having a plate shape, wherein the wafer is supported on its top surface, wherein the temperature control plate has a plurality of recesses.

[0021] The recess may contain a plurality of grooves or holes defined in the top or bottom surface of the temperature control plate.

[0022] Temperature control panels can be configured to have different volumes per unit area.

[0023] A trench can be defined such that at least one or more of its width and depth are different.

[0024] A hole can be defined such that at least one or more of the diameter and number of holes defined in a predetermined region are different.

[0025] The temperature control board can be configured to interlock with the thickness distribution of the thin film.

[0026] Each of the depressions can be defined at the point where the thickness of the film changes.

[0027] The temperature control panel can be provided in one of the following shapes when viewed from the side: convex, concave, or flat.

[0028] The temperature control plate can be made of the same material as the body, or of a material whose coefficient of thermal expansion is proportional to that of the body material.

[0029] In another embodiment, the epitaxial growth apparatus includes: a chamber configured to provide a high-temperature environment and in which a reaction gas flows; a rotating shaft rotatably provided within the chamber; a support provided on the upper end of the rotating shaft; and the aforementioned base supported by the support and on which a wafer is placed.

[0030] Details of one or more embodiments are now set forth in the accompanying drawings and the following description. Other features will become apparent from the description and drawings, as well as the claims. Simple Explanation of the Diagram

[0031] Figure 1 is a side view illustrating the support structure of a base used for epitaxial growth according to relevant technologies. Figure 2 is a graph showing the change of film thickness with film growth temperature during the epitaxial growth process according to relevant technologies. Figure 3 is a graph illustrating the thickness variation of the thin film within the wafer radius during the epitaxial growth process according to relevant technologies. Figure 4 is a side sectional view of a grooved base according to a first embodiment. Figure 5 is a side cross-sectional view of a hole-shaped base according to a second embodiment. Figure 6 is a side cross-sectional view of a convex base according to a third embodiment. Figure 7 is a side cross-sectional view of a concave base according to a fourth embodiment. Implementation

[0032] Exemplary embodiments will now be described in detail with reference to the accompanying drawings.

[0033] Figure 4 is a side sectional view of a grooved base according to a first embodiment.

[0034] According to a first embodiment, the base 110 may consist of a body 112 having a groove P provided on its top surface and a temperature control plate 114 placed in the groove P. A plurality of grooves G1 to G4 may be provided in the top surface of the temperature control plate 114, and a wafer W may be placed on the top surface of the temperature control plate 114.

[0035] The body 112 may have a circular plate shape and may have a groove P provided on its top surface, in which the temperature control plate 114 and the wafer W are placed. The depth of the groove P may be greater than at least the height of the temperature control plate 114, and its diameter may be the same as the diameter of each of the temperature control plate 114 and the wafer W. Alternatively, the shape of the groove P may vary depending on the shape of the temperature control plate 114, but is not limited thereto.

[0036] The temperature control plate 114 may have a circular plate shape and may have grooves G1 to G4 in its top surface. At least one or more of the width and depth of the grooves G1 to G4 disposed radially on the temperature control plate 114 may be defined differently, and each of the grooves G1 to G4 may be defined at a point where the thickness of the film changes radially on the wafer W, taking into account the thickness distribution of the film disposed on the top surface of the wafer W, but is not limited thereto.

[0037] When the dimensions and positions of the trenches G1 to G4 in the temperature control plate 114 are configured in various ways, even if a plurality of heaters (not shown) are placed above and below the base 110 to heat the base 110, because the temperature control plate 114 has a different volume per unit area due to the trenches G1 to G4, the base 110 together with the heaters (not shown) can radially control the heat energy supplied to the wafer W, and the contact area between the temperature control plate 114 and the wafer W can be controlled to radially control the heat transferred from the base 110 to the wafer W. Therefore, the temperature of the top surface of the wafer W can be uniform, and the thickness of the thin film placed on the top surface of the wafer W can be uniform.

[0038] The body 112 and the temperature control plate 114 can be manufactured separately, but can be made of materials with the same coefficient of thermal expansion, or of materials with different coefficients of thermal expansion in proportion. Grooves G1 to G4 can be machined separately in the temperature control plate 114, and the temperature control plate 114 can then be detachably mounted on the body 112.

[0039] Since the temperature control plate 114 is manufactured separately, the cost can be reduced compared to manufacturing the entire base 110. Furthermore, since the base 110 (on which the temperature control plate 114 is mounted on the body 112) does not change its overall shape, changes in airflow such as reaction gases within the processing chamber can be prevented, ensuring stable process operation. Moreover, the heat transfer of the base 110 can be altered simply by replacing the temperature control plate 114, allowing for a rapid response to changes in the process.

[0040] Figure 5 is a side cross-sectional view of a hole-shaped base according to a second embodiment.

[0041] According to a second embodiment, the base 210 may be composed of a body 212 and a temperature control plate 214, similar to that according to the first embodiment. A plurality of holes H1 to H4 may be provided to pass through the top and bottom surfaces of the temperature control plate 214, and the wafer W may be placed on the top surface of the temperature control plate 214.

[0042] Since the configuration of the main body 212 and the temperature control board 214 is the same as that according to the first embodiment, a detailed description will be omitted.

[0043] At least one or more of the diameters and the number per unit area (the density of holes in the temperature control plate) of the holes H1 to H4 provided in the radial direction of the temperature control plate 214 can be defined as different, and each of the holes H1 to H4 can be defined at the point where the thickness of the film changes in the radial direction of the wafer W, taking into account the thickness distribution of the film disposed on the top surface of the wafer W, but is not limited thereto.

[0044] In the base 210 according to the second embodiment, similar to the first embodiment, the size and position of each of the holes H1 to H4 can be varied in the temperature control plate 214 to control the heat transferred from the base 210 to the wafer W in the radial direction. Therefore, the temperature of the top surface of the wafer W can be uniform, and the thickness of the thin film disposed on the top surface of the wafer W can be uniform.

[0045] Figure 6 is a side cross-sectional view of a convex base according to a third embodiment.

[0046] According to a third embodiment of the base, when viewed from the side of the temperature control plate 314, the top surface of the temperature control plate 314 may be flat, and the bottom surface of the temperature control plate 314 may be provided in a convex shape. Furthermore, a plurality of grooves G1 to G4 may be defined radially in the top surface of the temperature control plate 314 to have different dimensions.

[0047] Alternatively, the shape of the groove on which the body (not shown) of the temperature control plate 314 is placed can also be provided to be the same as the shape of the convex bottom surface of the temperature control plate 314. Furthermore, the size and position of each of the grooves G1 to G4 can be configured in various ways in the temperature control plate 314.

[0048] The bottom surface of the temperature control board 314 can be manufactured into a convex shape to take into account the characteristics of the material that deforms at high temperatures during thin film growth, and the temperature control board 314 with the above shape can control the heat to be transferred according to the position of the wafer.

[0049] Even if the material does not deform at high temperatures, when the bottom surface of the temperature control plate 314 is manufactured into a convex shape, the volume at the center of the temperature control plate 314 can be greater than the volume at the edge of the temperature control plate 314. Furthermore, the width and depth of each of the grooves G1 to G4 defined in the top surface of the temperature control plate 314 can be configured in various ways, and therefore, the volume per unit area of ​​the temperature control plate 314 can be configured in a more diverse manner.

[0050] In the base according to the third embodiment, the bottom surface of the temperature control plate 314 can be provided in a convex shape to take into account the changes of the material at high temperature, and grooves G1 to G4 of various sizes can be defined in the top surface of the temperature control plate 314 to provide the same effect as that according to the first embodiment, which will not be described again here.

[0051] Figure 7 is a side cross-sectional view of a concave base according to a fourth embodiment.

[0052] According to a fourth embodiment of the base, when viewed from the side of the temperature control plate 414, the top surface of the temperature control plate 414 may be concave, and the bottom surface of the temperature control plate 414 may be provided to be flat. Furthermore, a plurality of grooves G1 to G4 may be defined radially in the top surface of the temperature control plate 414 to have different dimensions.

[0053] The bottom surface of the temperature control board 414 can be manufactured into a concave shape to take into account the characteristics of the material that deforms at high temperatures during thin film growth, and the temperature control board 414 with the above shape can control the heat to be transferred according to the position of the wafer.

[0054] In the base according to the fourth embodiment, the bottom surface of the temperature control plate 414 can be provided in a concave shape to take into account the changes of the material at high temperature, and grooves G1 to G4 of various sizes can be defined in the top surface of the temperature control plate 414 to provide the same effect as that according to the first embodiment, which will not be described again here.

[0055] According to various embodiments, the base can be composed of a body and a temperature control plate, and a plurality of grooves or hole-shaped recesses can be provided in the temperature control plate in various ways, and thus the contact area with the temperature control plate supporting the wafer can be configured differently.

[0056] Therefore, since the heat energy transferred to the wafer by the substrate and heater is provided uniformly in the radial direction, it has the following advantages: the upper temperature of the wafer supported on the substrate is provided uniformly in the radial direction, and the thickness of the thin film grown on the top surface of the wafer remains uniform.

[0057] Furthermore, since the grooves or holes are machined into the temperature control plate and then the temperature control plate is mounted on the body to form a base, the processing cost can be reduced, and the overall shape of the base can be maintained to avoid changes in the airflow in the processing chamber, thereby ensuring stable operation of the process. Moreover, the heat transfer of the base can be changed simply by replacing the temperature control plate to quickly respond to changes in the process.

[0058] Those skilled in this invention will be able to make various modifications and variations without departing from the basic characteristics of this invention.

[0059] Therefore, the embodiments of the present invention should be considered illustrative and not restrictive, and the technical spirit of the present invention is not limited to the above embodiments.

[0060] Therefore, the scope of this invention is not defined by the detailed description of the invention, but by the scope of the appended patent applications, and all differences within that scope should be understood to be included in this invention.

[0061] 11: Base 12: Rotation axis 13: Support components 110: Base 112:Ontology 114: Temperature control board 210: Base 212:Ontology 214: Temperature control board 314: Temperature control board 414: Temperature control board G1 to G4: Trench H1 to H4: Holes P: Groove W: Wafer

Claims

1. A base for an epitaxial growth apparatus, comprising: A body having a groove provided on one of its top surfaces, and a wafer being placed in the groove; And a temperature control plate, which is placed in the groove and has a plate shape, wherein the wafer is supported on a top surface thereon, wherein the temperature control plate has a plurality of recesses, and wherein the temperature control plate is configured to interlock with a thickness distribution of a thin film.

2. The base as claimed in claim 1, wherein the recesses include a plurality of grooves or a plurality of holes defined in the top or bottom surface of one of the temperature control plates.

3. The base as described in claim 2, wherein the temperature control plate is configured to have a different volume per unit area.

4. The base as described in claim 3, wherein the grooves are defined such that at least one or more of the width and depth of the grooves are different.

5. The base as claimed in claim 3, wherein the holes are defined such that at least one or more of the diameter and number of holes defined in a predetermined region are different.

6. The base as claimed in claim 1, wherein each of the recesses is defined at a point where the thickness of the film changes.

7. The base as claimed in claim 1, wherein the temperature control plate is provided to be one of a convex, concave, or flat shape when viewed from one side.

8. The base as claimed in claim 1, wherein the temperature control plate is made of the same material as the body, or of a material whose coefficient of thermal expansion is proportional to that of the material of the body.

9. An epitaxial growth apparatus, comprising: A chamber configured to provide a high-temperature environment and in which a reactive gas flows; a rotating shaft rotatably provided within the chamber; a support provided on one upper end of the rotating shaft; and a base as described in any one of claims 1 to 8, supported by the support and on which a wafer is placed.

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