Tray for solar cell film formation
By designing grooves and limit structures on the pallet body, the problem of electromagnetic field and air flow field in the PECVD process is solved, the uniformity of silicon wafer film formation and battery efficiency are improved, and more efficient solar cell manufacturing is achieved.
Patent Information
- Application Number
- CN202422519340.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-18
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-10-18
AI Technical Summary
In the PECVD process, the existing solar cell film formation pallets are like high walls adjacent to the bearing area, which destroys the uniformity of the electromagnetic field and the air flow field, resulting in abnormal film formation at the edge of the silicon wafer and reduced battery efficiency.
A pallet tray body is designed, each silicon wafer is equipped with a load bearing unit, including a groove and a load bearing area around the groove, and a limit rod and a limiting table are arranged around it to limit the slide out of the silicon wafer. The top of the silicon wafer is located between the limiting table and the limiting rod to ensure the uniformity of the electromagnetic field and the air flow field.
The film formation uniformity of silicon wafers and the conversion efficiency of solar cells in the PECVD process are improved, and the adverse effects of the edge effect of silicon wafers are avoided.
Smart Images
Figure CN223292640U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of solar cell manufacturing, in particular to a tray for solar cell film formation. Background Art
[0002] Thin-film / crystalline silicon heterojunction solar cells (hereinafter referred to as heterojunction solar cells, also known as HIT or HJT or SHJ solar cells) belong to the third generation of high-efficiency solar cell technology. They combine the advantages of first-generation crystalline silicon and second-generation silicon thin film, and have the characteristics of high conversion efficiency and low temperature coefficient. In particular, the conversion efficiency of double-sided heterojunction solar cells can reach more than 26%, and they have broad market prospects.
[0003] When making heterojunction solar cells, the core manufacturing process includes: using the plasma enhanced chemical vapor deposition (PECVD) process to deposit a very thin I-type intrinsic amorphous silicon film and a P-type amorphous silicon film on one side of the surface-textured N-type crystalline silicon, and depositing a thin I-type intrinsic amorphous silicon film and an N-type amorphous silicon film on the other side of the crystalline silicon. The amorphous silicon films on both sides can be made simultaneously or in steps; then, a transparent conductive oxide (ITO) film is deposited on both sides of the battery, and then metal electrodes are made on the ITO film.
[0004] When depositing amorphous silicon thin films on silicon wafers using the PECVD process, the following methods are used: Figure 1 The prior art tray shown is as follows Figure 4 As shown, the silicon wafer 2 is placed in the tray 1. Figure 1 As shown, a solar cell film forming tray 1 in the prior art includes a tray body 10 , and the tray body 10 includes a plurality of carrying units 12 . Figure 2 and Figure 3 They are Figure 1 The top view and cross-sectional view of the load-bearing unit 12 are shown in FIG. Figures 2 to 4 As shown, each carrying unit 12 includes a tray 120, a vent 121, a support member 122, a groove 123, a carrying area 124, and a stopper 125. The silicon wafer 2 is supported by the carrying area 124, with the middle portion of the silicon wafer suspended above the groove 123. The groove 123, the carrying area 124, and the stopper 125 form a two-step structure on the tray 120. The second step formed by the stopper 125 prevents the silicon wafer from sliding, and its height of 0.5-1 mm prevents the silicon wafer from deforming and forming overlapping edges at high temperatures.
[0005] However, if the PECVD process is performed with high airflow and power, the side of the limiting platform 125 adjacent to the supporting area 124 acts like a high wall close to the silicon wafer, disrupting the uniformity of the electromagnetic field and airflow field across the entire silicon wafer, resulting in a significant edge effect. This can cause film formation abnormalities within the 1.5-2 mm area around the edge of the silicon wafer and reduce cell efficiency.
[0006] Therefore, how to provide a tray for solar cell film formation that can improve the uniformity of the electromagnetic field and airflow field on the silicon wafers carried in the tray during the PECVD process, thereby improving the film formation uniformity and the conversion efficiency of solar cells has become a technical problem that needs to be urgently solved in the industry. Summary of the Invention
[0007] In response to the above-mentioned problems in the prior art, the utility model proposes a tray for solar cell film formation, comprising a tray body, wherein a carrying unit is arranged on the tray body for each silicon wafer, each carrying unit comprises a groove arranged in the middle and a carrying area surrounding each groove for carrying the silicon wafer, and each carrying area is surrounded by a limit rod and a limit platform for limiting the silicon wafer from sliding out of the carrying area, and the top of the silicon wafer arranged on the carrying area is located between the top of the limit platform and the top of the limit rod.
[0008] In one embodiment, the thickness of the silicon wafer carried by the carrying area is 120 μm-160 μm, the limiting platform is 10 μm-100 μm higher than the carrying area, and the limiting rod is 500 μm-1200 μm higher than the carrying area.
[0009] In one embodiment, the cross section of the limiting rod is circular, rectangular, square, elliptical or oval, and its cross-sectional area range is 0.5mm 2 -1.5mm 2 .
[0010] In one embodiment, the number of the limiting rods around each supporting area is 8, and the supporting area is suitable for accommodating a half-cell of a single crystal silicon wafer, and the half-cell of the single crystal silicon wafer includes a 105mm×210mm half-cell or a 91mm×182mm half-cell. Three limiting rods are set on each long side of each supporting area, and one limiting rod is set in the middle of each short side of each supporting area.
[0011] In one embodiment, the number of the limiting rods around each supporting area is 8, and the supporting area is suitable for accommodating a whole single crystal silicon wafer, and the whole single crystal silicon wafer includes a whole piece of 156mm×156mm, 166mm×166mm, 182mm×182mm or 210mm×210mm, and 2 limiting rods are set at each corner of each supporting area.
[0012] In one embodiment, the carrying area is a frame-shaped carrying area with chamfered corners, and the width of the frame-shaped carrying area with chamfered corners ranges from 0.5 mm to 3 mm.
[0013] In one embodiment, the depth of the groove is in the range of 0.5 mm to 1.2 mm, and the length and width of the groove are both in the range of 100 mm to 200 mm.
[0014] In one embodiment, a support member that does not protrude beyond the groove is provided at the bottom of the groove corresponding to the center position of the silicon wafer or the main gate position.
[0015] In one embodiment, a plurality of ventilation holes passing through the tray body are provided at the bottom of the groove.
[0016] In one embodiment, the tray body has a width ranging from 100 cm to 200 cm, a length ranging from 100 cm to 200 cm, and a thickness ranging from 0.3 cm to 1 cm.
[0017] Compared to the existing technology, which features high walls on the sides of the wafer-carrying area, which disrupt the uniformity of the electromagnetic and airflow fields across the wafer, leading to film formation anomalies and reduced cell efficiency in the area surrounding the wafer, the present solar cell film-forming tray includes a tray body with a recess for each wafer. Surrounding each recess are a supporting area for the wafer, and each supporting area is surrounded by a limiting rod and a limiting platform to prevent the wafer from sliding out of the area. The top of the wafer placed on the supporting area is positioned between the top of the limiting platform and the top of the limiting rod. This invention improves the uniformity of the electromagnetic and airflow fields on the wafers carried in the tray during the PECVD process, thereby improving film formation uniformity and the conversion efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or characteristics may have the same or similar reference numerals.
[0019] Figure 1 This is an overall top view of a tray for solar cell film formation in the prior art.
[0020] Figure 2 for Figure 1 Schematic diagram of the top view of the load-bearing unit.
[0021] Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure of the load-bearing unit.
[0022] Figure 4 for Figure 1 Schematic diagram of the cross-sectional structure when the carrying unit carries the silicon wafer 2.
[0023] Figure 5 This is an overall top view of the tray for solar cell film formation in the present invention.
[0024] Figure 6for Figure 5 Schematic diagram of the top view of the load-bearing unit.
[0025] Figure 7 For the Figure 6 Schematic diagram of the cross-sectional structure of the load-bearing unit along the AA cutting line.
[0026] Figure 8 For the Figure 6 Schematic diagram of the cross-sectional structure of the load-bearing unit along the BB cutting line.
[0027] Figure 9 for Figure 7 Schematic diagram of the cross-sectional structure when the carrying unit carries the silicon wafer 2.
[0028] Figure 10 for Figure 8 Schematic diagram of the cross-sectional structure when the carrying unit carries the silicon wafer 2. Specific implementation plan
[0029] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments to provide a clearer understanding of the purposes, features, and advantages of the present invention. It should be understood that the various aspects described below in conjunction with the accompanying drawings and specific embodiments are merely illustrative and should not be construed as limiting the scope of protection of the present invention. Unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" include plural referents.
[0030] The present invention will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. It is worth noting that the embodiments described below do not limit the present invention, and any structural or functional changes made by a person skilled in the art based on these embodiments are included in the scope of protection of the present invention.
[0031] Figure 5 This is an overall top view of the solar cell film forming tray of the present invention. Figure 6 for Figure 5 A schematic diagram of the top view of the load-bearing unit in FIG. Figure 7 and Figure 8 Along Figure 6 Schematic diagram of the cross-sectional structure of the load-bearing unit along the AA and BB cutting lines. Figure 9 and Figure 10 They are Figure 7 、 Figure 8 Schematic diagram of the cross-sectional structure when the carrying unit carries the silicon wafer 2.
[0032] like Figure 5As shown, the solar cell film forming tray 3 of the present invention includes a tray body 30, which includes multiple carrying units 32. The tray 3 can be a composite tray, which can include a substrate and a coating covering the substrate. The substrate can be made of any of graphite, carbon fiber, and silicon carbide, and the coating can be made of any of aluminum, silver, copper, or alloys thereof. The solar cell film forming tray 3 has a width ranging from 100 cm to 200 cm, a length ranging from 100 cm to 200 cm, and a thickness ranging from 0.3 cm to 1 cm.
[0033] like Figures 6 to 10 As shown, each carrying unit 32 includes a plate 320, a vent 321, a support member 322, a groove 323, multiple limiting rods 324, a carrying area 325, and a limiting platform 326. The groove 323 is located in the center of each carrying unit and is used to suspend the center of the silicon wafer 2. The carrying area 325 surrounds each groove 323 and is used to support the silicon wafer 2. The limiting platform 326 and multiple limiting rods 324 are located at the edge of the carrying area 325 to prevent the silicon wafer 2 from sliding out of the carrying area 325. The top of the silicon wafer 2 placed on the carrying area 325 is located between the top of the limiting platform 326 and the top of the limiting rods 324.
[0034] The thickness of the silicon wafer 2 carried by the carrying area 325 is 120μm-160μm (micrometers). The limiting platform 326 is set around the carrying area 325. The limiting platform 326 is 10μm-100μm higher than the carrying area 325, and the limiting rod 324 is 500μm-1200μm higher than the carrying area 325. The cross section of the limiting rod 324 can be circular, rectangular, square, elliptical or oval, etc., and its cross-sectional area range is 0.5mm 2 -1.5mm 2 (square millimeters).
[0035] Several vent holes 321 are provided at the bottom of the groove 323 and extend through the tray 320. Each carrier unit 32 may have two or four vent holes 321. When the silicon wafer 2 and tray 3 are placed in the PECVD reaction chamber and vacuum is applied, the vent holes 321 allow residual process gas from beneath the silicon wafer 2 to be extracted, preventing contamination of the reaction chamber by the residual process gas. Furthermore, before the silicon wafer 2 leaves the reaction chamber, when atmospheric air is injected into the vacuum chamber, the vent holes 321 allow the gas pressure beneath the silicon wafer 2 to increase as external pressure increases, preventing the external pressure from crushing the silicon wafer 2.
[0036] The support member 322 is positioned at the bottom of the groove 323, corresponding to the center of the silicon wafer or the main gate position, and does not protrude above the groove 323. The support member 322 and the disk body 320 can be integrally formed. The support member 322 and the disk body 320 can also be separate structures. For example, the support member 322 can be connected to the disk body 320 in a snap-fit manner and the corresponding support height can be adjusted.
[0037] The depth of the groove 323 ranges from 0.5 mm to 1.2 mm (millimeter), and the length and width of the groove 323 range from 100 mm to 200 mm. The cross-section of the groove 323 can be square. The carrying area 325 is suitable for accommodating silicon wafers of sizes such as 125 mm × 125 mm, 156 mm × 156 mm, 166 mm × 166 mm, 182 mm × 182 mm, 91 mm × 182 mm, 105 mm × 210 mm, or 210 mm × 210 mm used in the industry in the past, present, and future. The carrying area 325 is a frame-shaped carrying area with chamfered corners, and the width of the frame-shaped carrying area with chamfered corners ranges from 0.5 mm to 3 mm.
[0038] In such Figure 5 and Figure 6 In the embodiment shown, the number of the limiting rods 324 around each supporting area 325 is 8, and the supporting area 325 is suitable for accommodating a whole single crystal silicon wafer, and the whole single crystal silicon wafer includes a whole piece of 156mm×156mm, 166mm×166mm, 182mm×182mm or 210mm×210mm, and two limiting rods 325 are set at each corner of each supporting area 325.
[0039] In other embodiments, the number of the limiting rods 324 around each supporting area 325 may be 8, and the supporting area 325 is suitable for accommodating a single crystal silicon wafer half-piece, and the single crystal silicon wafer half-piece includes a 105mm×210mm half-piece or a 91mm×182mm half-piece. Three limiting rods 324 are set on each long side of each supporting area 325, and one limiting rod 324 is set in the middle of each short side of each supporting area 325.
[0040] When the PECVD process is performed on the cleaned and textured silicon wafer, the silicon wafer 2 is first Figure 9 or Figure 10As shown, the tray 3 is placed on the supporting area 325 of the solar cell film formation tray 3, with the central area of the silicon wafer 2 suspended above the groove 323. The central area of the silicon wafer 2 or the main grid line is supported by the support member 322. The tray 3 is then transferred to the PECVD process chamber by a robotic arm or roller. The PECVD process chamber is then evacuated and the reactive gas is introduced. The RF power is turned on. Because the top of the limit table 326 is lower than the silicon wafer 2 placed on the supporting area 325 and the limit rod 324 is very small, it does not hinder the airflow through the silicon wafer 2. The electromagnetic field and airflow field are basically uniform on the same silicon wafer 2, and the film thickness at the edge and center of the silicon wafer is basically the same, thus avoiding the adverse effects of edge effects.
[0041] The present invention's solar cell film-forming tray includes a tray body with a supporting unit for each silicon wafer. Each supporting unit includes a central groove and a supporting area surrounding each groove for supporting the silicon wafer. Each supporting area is surrounded by a limiting rod and a limiting platform to prevent the silicon wafer from sliding out of the supporting area. The top of the silicon wafer placed on the supporting area is positioned between the top of the limiting platform and the top of the limiting rod. This invention improves the uniformity of the electromagnetic field and airflow field on the silicon wafers carried in the tray during the PECVD process, thereby improving film formation uniformity and the conversion efficiency of the solar cell.
[0042] It should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
[0043] The above embodiments are provided for persons familiar with the art to implement or use the present invention. Personnel familiar with the art may make various modifications or changes to the above embodiments without departing from the inventive concept of the present invention. Therefore, the scope of protection of the present invention is not limited to the above embodiments, but should be the maximum scope of the innovative features mentioned in the claims.
Claims
1. A solar cell film forming tray, comprising a tray body, wherein a carrying unit is provided on the tray body for each silicon wafer, each carrying unit comprising a groove provided in the middle and a carrying area surrounding each groove for carrying the silicon wafer, characterized in that: Each carrying area is surrounded by a limiting rod and a limiting platform for limiting the silicon wafer from sliding out of the carrying area. The top of the silicon wafer arranged on the carrying area is located between the top of the limiting platform and the top of the limiting rod.
2. The solar cell film forming tray according to claim 1, wherein: The thickness of the silicon wafer carried by the carrying area is 120 μm-160 μm, the limiting platform is 10 μm-100 μm higher than the carrying area, and the limiting rod is 500 μm-1200 μm higher than the carrying area.
3. The solar cell film forming tray according to claim 1, wherein: The cross section of the limit rod is circular, rectangular, square, elliptical or oval, and its cross section area range is 0.5mm 2 -1.5mm 2 .
4. The solar cell film forming tray according to claim 1 or 2, wherein: The number of the limiting rods around each supporting area is 8, and the supporting area is suitable for accommodating half a single crystal silicon wafer, and the half a single crystal silicon wafer includes a 105mm×210mm half wafer or a 91mm×182mm half wafer. Three limiting rods are set on each long side of each supporting area, and one limiting rod is set in the middle of each short side of each supporting area.
5. The solar cell film forming tray according to claim 1 or 2, wherein: The number of the limiting rods around each supporting area is 8, and the supporting area is suitable for accommodating a whole piece of single crystal silicon wafer, and the whole piece of single crystal silicon wafer includes a whole piece of 156mm×156mm, 166mm×166mm, 182mm×182mm or 210mm×210mm, and 2 limiting rods are set at each corner of each supporting area.
6. The solar cell film forming tray according to claim 1, wherein: The bearing area is a frame-shaped bearing area with chamfered corners, and the width of the frame-shaped bearing area with chamfered corners ranges from 0.5 mm to 3 mm.
7. The solar cell film forming tray according to claim 1, wherein: The depth of the groove is in the range of 0.5 mm to 1.2 mm, and the length and width of the groove are in the range of 100 mm to 200 mm.
8. The solar cell film formation tray according to claim 1, wherein: A support member that does not exceed the height of the groove is provided at the bottom of the groove at a position corresponding to the center of the silicon wafer or the main gate position.
9. The solar cell film forming tray according to claim 1, wherein: The bottom of the groove is provided with a plurality of ventilation holes that pass through the tray body.
10. The solar cell film forming tray according to claim 1, wherein The width of the tray body ranges from 100cm to 200cm, the length ranges from 100cm to 200cm, and the thickness ranges from 0.3cm to 1cm.