Silicon wafer bearing device with high surface temperature uniformity
By designing a combination structure of steps and baffles on the silicon wafer support device, and optimizing the material and support point settings, the problem of uneven temperature on the silicon wafer surface was solved, resulting in higher coating uniformity and improved efficiency of photovoltaic cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-03-31
AI Technical Summary
Existing silicon wafer carrier devices cause uneven surface temperature of silicon wafers during PECVD coating, affecting the uniformity of thin film deposition and the electrical performance parameters of photovoltaic cells, resulting in a decrease in yield.
Design a silicon wafer support device with high surface temperature uniformity. This is achieved by setting a combination of steps and baffles in the storage tank, including discontinuous and continuous structures, optimizing the size and number of steps and baffles, using materials such as carbon/carbon hard plate or stainless steel plate, processing an array of grooves to disperse heat, and setting fulcrums to support the silicon wafer.
It improves the temperature uniformity of the silicon wafer surface, reduces the edge effect during the coating process, improves the coating uniformity of the silicon wafer surface and the photoelectric efficiency of the photovoltaic cell, and increases the yield of silicon wafer coating.
Smart Images
Figure CN121759931A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photovoltaic equipment technology, and specifically relates to a silicon wafer support device with high surface temperature uniformity used in plasma-enhanced chemical vapor deposition (PECVD) coating process. Background Technology
[0002] In the production of photovoltaic silicon wafers, PECVD technology is typically used to deposit an intrinsic / doped amorphous silicon layer on the wafer surface. This process requires placing a large number of silicon wafers on a support device and feeding them into a coating equipment for heating and coating at a high temperature of 200-300℃. The performance of the support device directly affects the uniformity of the coating and the yield of silicon wafers.
[0003] The uniformity, density, and optical properties of thin film deposition on silicon wafers have a decisive impact on the final conversion efficiency of photovoltaic cells. The uniformity of thin film deposition directly and significantly depends on the uniformity of the temperature field within the silicon wafer itself. If the supporting device itself has uneven heat conduction and dissipation, leading to temperature differences at different locations on its surface, a series of problems will arise: the deposition rate is faster at higher temperatures, resulting in greater thickness; the deposition rate is slower at lower temperatures, resulting in thinner thickness. This uneven thickness directly manifests as color differences in the solar cells (color aberration), leading to dispersion in the electrical performance parameters of the photovoltaic cells and a significant decrease in yield. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to overcome the shortcomings of the prior art and provide a silicon wafer support device with high surface temperature uniformity.
[0005] Technical solution: A silicon wafer support device with high surface temperature uniformity includes a storage tank for supporting silicon wafers and completing the plasma-enhanced chemical vapor deposition coating process. The storage tank has a support point inside and steps and baffles on its edge. The combination of baffles and steps includes three forms: discontinuous steps and discontinuous baffles, discontinuous steps and continuous baffles, and continuous steps and discontinuous baffles. By designing the shape, size and number of the steps and baffles, the purpose of effectively dispersing heat and improving the surface temperature uniformity of the storage tank is achieved.
[0006] A further improvement of the present invention is that the storage slot includes a first storage slot, a second storage slot, and a third storage slot; the fulcrum includes a first fulcrum, a second fulcrum, and a third fulcrum; the retaining edge includes a first retaining edge, a second retaining edge, and a third retaining edge arranged in an intermittent structure; and the step includes a first step, a second step, and a third step arranged in an intermittent structure. The first retaining edge and the first step are adjacent and connected; the second retaining edge and the second step are separated and connected; and the third retaining edge and the third step are not adjacent and not connected.
[0007] A further improvement of the present invention is that the storage slot includes a fourth storage slot, the fulcrum includes a fourth fulcrum, the retaining edge includes a fourth retaining edge with an intermittent structure, and the step includes a fourth step with a continuous structure.
[0008] A further improvement of the present invention is that the storage slot includes a fifth storage slot, the fulcrum includes a fifth fulcrum, the retaining edge includes a fifth retaining edge with a continuous structure, and the step includes a fifth step with a discontinuous structure.
[0009] A further improvement of the present invention is that the width of the step is 1 to 5 mm, the thickness of the step is 0.2 to 1.2 mm, the width of the retaining edge is 1 to 5 mm, and the thickness of the retaining edge is 0.2 to 1.2 mm.
[0010] A further improvement of the present invention is that the shape of the retaining edge is frustum or rectangle, and the shape of the step is frustum, truncated cone or rectangle.
[0011] A further improvement of the present invention is that the number of steps on the long side of the storage slot is 1 to 6, the number of retaining edges on the long side of the storage slot is 1 to 6, the number of steps on the wide side of the storage slot is 1 to 4, and the number of retaining edges on the wide side of the storage slot is 1 to 4.
[0012] A further improvement of the present invention is that the number of fulcrums is 1 to 5, the height of the fulcrums is 0.05 to 0.75 mm, and the diameter of the fulcrums is 2 to 6 mm.
[0013] A further improvement of the present invention is that the storage tank is an array of grooves machined on the upper surface of a carbon / carbon hard plate, stainless steel plate, aluminum alloy plate, or titanium alloy plate.
[0014] Compared with the prior art, the present invention achieves at least the following beneficial effects: This invention discloses a silicon wafer support device with high surface temperature uniformity. The device is made of large-size carbon / carbon rigid sheet, stainless steel sheet, aluminum alloy sheet, or titanium alloy sheet. An array of grooves machined on its upper surface serves as storage slots. By rationally designing the steps and edges of these slots, the temperature uniformity of each slot is improved, thereby enhancing the temperature uniformity of the silicon wafer surface, reducing edge effects during PECVD deposition, and improving the deposition uniformity of the silicon wafer surface. This ultimately increases the photoelectric efficiency of the photovoltaic cells. The provided support points prevent the silicon wafer from collapsing and contacting the bottom of the storage slot, thus preventing contamination, and also prevent excessive collapse that could cause the wafer to crack. Simultaneously, this ensures temperature uniformity on the silicon wafer surface, improving the yield of silicon wafer deposition. Attached Figure Description
[0015] Figure 1This is a schematic diagram of the silicon wafer carrier structure; Figure 2 A schematic diagram of a discontinuous side and discontinuous step type silicon wafer support device when the first side and the first step are adjacent and connected; Figure 3 This is a magnified view of point A; Figure 4 A schematic diagram of a discontinuous side and discontinuous step type silicon wafer support device when the second side and the second step are separated and connected; Figure 5 This is a magnified view of point B; Figure 6 A schematic diagram of a discontinuous step silicon wafer support device in which the third stop edge and the third step are not adjacent or connected; Figure 7 This is a magnified view of point C; Figure 8 Schematic diagram of a continuous stepped silicon wafer support device with intermittent edge protection; Figure 9 This is a magnified view of point D; Figure 10 Schematic diagram of a continuous edge-stopped stepped silicon wafer support device; Figure 11 This is a magnified view of point E; Figure 12 Schematic diagram of a continuous stepped silicon wafer support device with continuous edge guards; Figure 13 This is a magnified view of point F; Figure 14 Image of an uncoated silicon wafer surface; Figure 15 Image of the silicon wafer surface after coating on a stepped silicon wafer support device with intermittent edge blocking.
[0016] Explanation of reference numerals in the attached figures: 1-Storage slot; 11-First storage slot; 21-Second storage slot; 31-Third storage slot; 41-Fourth storage slot; 51-Fifth storage slot; 61-Sixth storage slot; 12-First step; 22-Second step; 32-Third step; 42-Fourth step; 52-Fifth step; 62-Sixth step; 13-First fulcrum; 23-Second fulcrum; 33-Third fulcrum; 43-Fourth fulcrum; 53-Fifth fulcrum; 63-Sixth fulcrum; 14-First retaining edge; 24-Second retaining edge; 34-Third retaining edge; 44-Fourth retaining edge; 54-Fifth retaining edge; 64-Sixth retaining edge. Detailed Implementation
[0017] Various exemplary embodiments of the present invention will now be described in detail. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the invention. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.
[0018] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.
[0019] The embodiments primarily utilize two types of silicon wafer support devices: a specially designed intermittent edge-intermittent step and a conventional continuous edge-continuous step. Radiation heating is the main heating method. By comparing the structures of different storage tanks, the study investigates the impact of different tank structures on differences in temperature transfer uniformity and on the magnitude of the temperature range on the silicon wafer surface.
[0020] Example 1 For the structural design of each storage slot on the large-size silicon wafer carrier, please refer to [reference needed]. Figure 1 and 2 The edge is designed as an intermittent edge, and the step is designed as an intermittent step. The step is 2mm long, 2mm wide, and 1mm thick. The edge is 2mm long, 2mm wide, and 1mm thick. The step and the edge are adjacent and connected.
[0021] The intermittent stepped silicon wafer carrier device with discontinuous edge is placed in a vacuum high-temperature chamber at 250°C and radiated through a lower heating plate. The distance between the lower heating plate and the silicon wafer carrier device is 25mm, and the heating time is 100s. The surface temperatures of the edge corner silicon wafer and the center silicon wafer supported by the silicon wafer carrier device are measured.
[0022] By measuring the surface temperature distribution of the central silicon wafer, the results show that the high-temperature area is mainly concentrated in the central region of the silicon wafer surface, while the low-temperature area is concentrated in the four sides and adjacent areas of the silicon wafer, especially the four corners of the silicon wafer where the temperature is the lowest. The low-temperature area adjacent to the wide side of the silicon wafer is larger and lower in temperature than the low-temperature area adjacent to the long side. The maximum surface temperature of the central silicon wafer is 220.7℃, the minimum is 213.9℃, and the temperature range is 6.8℃.
[0023] Measurements of the temperature distribution at the edge corner of the silicon wafer revealed a pattern: high-temperature regions were mainly concentrated in the central area of the wafer surface, while low-temperature regions were concentrated around the edges and adjacent areas. The low-temperature regions adjacent to the wider edges of the wafer were larger and lower in temperature than those adjacent to the longer edges. Furthermore, the low-temperature regions along the wider and longer edges adjacent to the environment were lower than those adjacent to the internal storage tanks. The maximum surface temperature at the edge corner of the silicon wafer was 220.4℃, the minimum was 210.1℃, and the temperature range was 10.3℃. Figure 14 This is an image of the surface of an uncoated silicon wafer. Figure 15 Images show the surface of a silicon wafer after coating on a specially designed intermittent stepped silicon wafer support device. It is evident that the uniformity of temperature distribution on the silicon wafer surface is highly correlated with the uniformity of the coating on the wafer surface.
[0024] Comparative Example 1 See Figure 12 The large-size silicon wafer carrier device has a continuous edge design, and the steps are designed as continuous steps with a step width of 2mm and a step thickness of 1mm. The edge width is 2mm and the edge thickness is 1mm.
[0025] The continuous stepped silicon wafer carrier with continuous edge is placed in a vacuum high-temperature chamber at 250°C and radiated through a lower heating plate. The distance between the lower heating plate and the silicon wafer carrier is 25mm, and the heating time is 100s. The surface temperatures of the silicon wafers at the edge corners and the center of the silicon wafer carrier are measured.
[0026] By measuring the surface temperature distribution of the central silicon wafer, the results show that the high-temperature region is mainly concentrated in the central area of the silicon wafer surface, while the low-temperature region is concentrated in the four sides and adjacent areas of the silicon wafer. The low-temperature distribution area adjacent to the wide side of the silicon wafer is larger and has a lower temperature than the low-temperature distribution area adjacent to the long side of the silicon wafer. The maximum surface temperature of the central silicon wafer is 216.1℃, the minimum is 199.2℃, and the temperature range is 16.9℃.
[0027] Measurements of the temperature distribution at the edge corner of the silicon wafer revealed that the high-temperature region was mainly concentrated in the central area of the wafer surface, while the low-temperature region was concentrated around the edges and adjacent areas. The low-temperature region adjacent to the wider edge of the wafer was larger and lower in temperature than the low-temperature region adjacent to the longer edge. Furthermore, the low-temperature regions along the wider and longer edges adjacent to the environment were lower than those adjacent to the internal storage tank. The maximum surface temperature at the edge corner of the silicon wafer was 215.8℃, the minimum was 197.8℃, and the temperature range was 18.0℃.
[0028]
[0029]
[0030] Furthermore, by comparing the temperatures at different sampling points on the long and wide sides of the central silicon wafer supported by the intermittent side intermittent step type and the continuous side continuous step type silicon wafer coating device, the results show that the intermittent side intermittent step type silicon wafer support device has higher temperature uniformity, higher overall surface temperature, and smaller silicon wafer surface temperature range under the same conditions than the continuous side continuous step type silicon wafer support device.
[0031] Furthermore, by comparing the surface temperature uniformity of the central silicon wafer and the edge corner silicon wafers of four types of silicon wafer support devices—intermittent side intermittent step, intermittent side continuous step, continuous side intermittent step, and continuous side continuous step—it can be concluded that the intermittent side intermittent step type silicon wafer support device is the best among the four structures, as it can greatly improve the surface temperature distribution uniformity of the silicon wafer.
[0032] Example 2 The structure of each storage slot on the silicon wafer carrier is designed. The baffle of each storage slot is designed as an intermittent baffle, and the step is designed as an intermittent step. The step is 2mm long, 2mm wide, and 1mm thick. The baffle is 2mm long, 2mm wide, and 1mm thick. The support points on the surface of the storage slot play a supporting role for the silicon wafer during the coating process. The size and number of support points on the surface of the storage slot are designed.
[0033] First, four support points are designed on the upper surface of each storage slot of the intermittent stepped silicon wafer support device with intermittent side stops. These four support points are evenly distributed along the center lines of the two wide sides of the silicon wafer. (See...) Figure 4 The diameter of each fulcrum is 3mm. The height of the fulcrum is changed to 0mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, and 0.35mm respectively.
[0034]
[0035] By comparing the effects of different fulcrum heights on the surface temperature uniformity of the central silicon wafer, it can be seen that as the fulcrum height increases, the temperature range of the central silicon wafer surface decreases, albeit by a small margin. This is because the fulcrum size is too small to significantly alter the heat capacity of the storage tank surface. Therefore, in addition to providing support for the silicon wafer, the fulcrum, when in contact with the wafer surface, can also, to some extent, regulate the heat concentration on the wafer surface, affecting the temperature distribution and reducing the temperature range.
[0036] Secondly, different numbers of support points were designed on each storage slot of the intermittent stepped silicon wafer support device with intermittent side guards. Each support point had a diameter of 3 mm and a height of 0.3 mm, with the numbers of support points being 1, 2, 3, and 4, respectively. The support points were located on a diagonal line of the storage slot. The experimental results were basically consistent with those obtained by changing the height of the support points. Changing the number and location of the support points had little impact on the temperature uniformity of the silicon wafer surface and could only slightly affect the heat concentration on the silicon wafer surface. The main reason for this was that the support point size was too small, thus having little impact on the heat capacity of the storage slot surface.
[0037] Example 3 See Figure 2-7 The structure of each storage slot on the silicon wafer carrier device is designed. The baffle of each storage slot is designed as an intermittent baffle, and the step is designed as an intermittent step. The step is 2mm long, 2mm wide, and 1mm thick, and the baffle is 2mm long, 2mm wide, and 1mm thick. In order to maximize the temperature uniformity of heat transfer on the surface of the silicon wafer carrier device to meet the requirements of uniformity of silicon wafer surface coating and reduce the edge effect of silicon wafer surface coating. The structure is divided into three design schemes for the baffles and steps: the storage tank 1 includes a first storage tank 11, a second storage tank 21, and a third storage tank 31; the support points include a first support point 13, a second support point 23, and a third support point 33; the baffles include a first baffle 14, a second baffle 24, and a third baffle 34 with an intermittent structure; and the steps include a first step 12, a second step 22, and a third step 32 with an intermittent structure. The first baffle 14 and the first step 12 are adjacent and connected, with a thicker material and a larger area at the baffle position, resulting in lower temperature uniformity on the silicon wafer surface. The second baffle 24 is separated from and connected to the second step 22, with a thicker material at the baffle position, resulting in moderate temperature uniformity on the silicon wafer surface. The third baffle 34 is not adjacent to or connected to the third step 32, with a relatively thinner material and a smaller area at the baffle position, providing a channel with lower thermal resistance and promoting balanced heat flow. Thus, based on the excellent material, its heat diffusion capability is further enhanced, achieving relatively better temperature uniformity.
[0038] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.
Claims
1. A silicon wafer support device with high surface temperature uniformity, characterized in that, The storage tank (1) is used to support silicon wafers and complete the plasma-enhanced chemical vapor deposition coating process. The storage tank (1) is provided with a support point inside. The storage tank (1) is provided with steps and baffles on its edge. The combination type of baffles and steps includes three forms: discontinuous steps and discontinuous baffles, discontinuous steps and continuous baffles, and continuous steps and discontinuous baffles. The steps and baffles, by designing their shape, size and number, can effectively disperse heat and improve the surface temperature uniformity of the storage tank.
2. The silicon wafer support device with high surface temperature uniformity according to claim 1, characterized in that, The storage slot (1) includes a first storage slot (11), a second storage slot (21), and a third storage slot (31). The fulcrum includes a first fulcrum (13), a second fulcrum (23), and a third fulcrum (33). The side rails include a first side rail (14), a second side rail (24), and a third side rail (34) with an intermittent structure. The steps include a first step (12), a second step (22), and a third step (32) with an intermittent structure. The first side rail (14) and the first step (12) are adjacent and connected. The second side rail (24) and the second step (22) are separated and connected. The third side rail (34) and the third step (32) are not adjacent and not connected.
3. The silicon wafer support device with high surface temperature uniformity according to claim 1, characterized in that, The storage slot (1) includes a fourth storage slot (41), the fulcrum includes a fourth fulcrum (43), the side rail includes a fourth side rail (44) with an intermittent structure, and the step includes a fourth step (42) with a continuous structure.
4. The silicon wafer support device with high surface temperature uniformity according to claim 1, characterized in that, The storage slot (1) includes a fifth storage slot (51), the fulcrum includes a fifth fulcrum (53), the side rail includes a fifth side rail (54) with a continuous structure, and the step includes a fifth step (52) with a discontinuous structure.
5. A silicon wafer support device with high surface temperature uniformity according to claim 1, characterized in that, The width of the step is 1-5mm, the thickness of the step is 0.2-1.2mm, the width of the edge is 1-5mm, and the thickness of the edge is 0.2-1.2mm.
6. The silicon wafer support device with high surface temperature uniformity according to claim 1, characterized in that, The shape of the retaining edge is frustum or rectangle, and the shape of the step is frustum, truncated cone, or rectangle.
7. A silicon wafer support device with high surface temperature uniformity according to claim 2, characterized in that, The storage slot (1) has 1 to 6 steps on its long side, 1 to 6 guards on its long side, 1 to 4 steps on its wide side, and 1 to 4 guards on its wide side.
8. A silicon wafer support device with high surface temperature uniformity according to claim 1, characterized in that, The number of fulcrums is 1 to 5, the height of the fulcrums is 0.05 to 0.75 mm, and the diameter of the fulcrums is 2 to 6 mm.
9. A silicon wafer support device with high surface temperature uniformity according to any one of claims 1-8, characterized in that, The storage slot (1) is an array of grooves machined on the upper surface of carbon / carbon hard plate, stainless steel plate, aluminum alloy plate, or titanium alloy plate.