Conveying and spraying device for removing BSG from silicon wafer

Abstract

The utility model discloses a conveying and spraying device for removing a BSG from a silicon wafer, which comprises a roller frame and a plurality of conveying rollers arranged in the roller frame at intervals along the conveying direction of the silicon wafer, a spraying assembly is transversely arranged above the roller frame, the conveying rollers comprise a thick roller and a thin roller located in the spraying range of the spraying assembly, and the thick roller is arranged above the spraying assembly. A plurality of protruding rings are coaxially arranged on the thin roller at intervals, and the outer diameter of the protruding rings is the same as the diameter of the thick roller. According to the utility model, the contact area between the transmission roller and the back surface of the silicon wafer can be reduced when the silicon wafer is sprayed, so that residual water attached to the back surface of the passing silicon wafer is reduced, and the influence on the concentration of an acid tank is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to a conveying and spraying device for removing BSG from silicon wafers. Background Art

[0002] At present, the process of crystalline silicon solar cell wafers has gradually moved towards standardization, automation, and mass production. Generally, a PN junction is prepared by introducing an appropriate amount of boron trichloride into the front side of an n-type silicon wafer. At the same time, a by-product BSG (borosilicate glass) dead layer will be formed on the front, back, and edges of the silicon wafer. The presence of BSG makes the surface of the silicon wafer easily absorb moisture in the air, which will cause a decrease in current and power attenuation; the presence of the dead layer greatly increases the recombination of electrons in the emitter region, which will cause a decrease in the minority carrier lifetime, and further reduce Voc and Isc; in addition, the presence of borosilicate glass causes color difference after PECVD. Therefore, it is necessary to remove the BSG dead layer on the back and edges of the silicon wafer after boron diffusion.

[0003] The existing method for removing BSG is mainly through pickling. Before the silicon wafer enters the HF (hydrofluoric acid) tank, a spray pipe is arranged above the transmission roller to continuously spray the passing silicon wafer, and a water film is laid on the front side of the silicon wafer through uniform spraying to prevent the front side of the silicon wafer from being corroded by HF. However, in this process, the transmission roller will also be sprayed, resulting in a large amount of residual water on the surface of the transmission roller and adhering to the back of the passing silicon wafer, and being carried into the acid tank with the silicon wafer, thereby reducing the concentration of the HF tank and increasing acid consumption. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a conveying and spraying device for removing BSG from silicon wafers, which can reduce the contact area between the transmission roller and the back of the silicon wafer when spraying the silicon wafer, thereby reducing the residual water adhering to the back of the passing silicon wafer and reducing the influence on the concentration of the acid tank.

[0005] To achieve the above purpose, the technical solution adopted by the utility model is: a conveying and spraying device for removing BSG from silicon wafers, including a roller frame, a plurality of conveying rollers arranged at intervals along the silicon wafer conveying direction in the roller frame, a spraying assembly transversely arranged above the roller frame, among the plurality of conveying rollers, there are thick rollers and thin rollers located within the spraying range of the spraying assembly, and a plurality of convex rings are coaxially arranged at intervals on the thin rollers, and the outer diameter of the convex ring is the same as the diameter of the thick roller.

[0006] A further improvement of the utility model is that the spraying assembly includes a spray pipe transversely arranged above the roller frame, a water tank is connected above the spray pipe through a water pipe, and a flow valve and a control valve are arranged on the water pipe.

[0007] A further improvement of the present utility model is that a plurality of water pipes are provided, which are arranged at intervals between the spray pipe and the water tank. A plurality of partitions are provided in the spray pipe, and the interior thereof is divided into a plurality of spray chambers corresponding to the number of water pipes.

[0008] A further improvement of the present utility model is that the surface of the convex ring is covered with a hydrophobic coating.

[0009] A further improvement of the present utility model is that the control valve is a solenoid valve. A proximity switch for detecting the approach of the silicon wafer is provided on the roller frame, and the proximity switch is electrically connected to the solenoid valve.

[0010] A further improvement of the present utility model is that a ring-shaped arc-shaped protrusion is provided on the outer periphery of the convex ring. The cross-section of the arc-shaped protrusion is hemispherical, and the diameter of the hemisphere is the same as the thickness of the convex ring.

[0011] A further improvement of the present utility model is that a flow meter is provided on the water pipe.

[0012] A further improvement of the present utility model is that at least three thin rollers are provided.

[0013] The beneficial effects of the present utility model are as follows:

[0014] By differentiating the conveying rollers into thick rollers and thin rollers in the present utility model, and arranging the thin rollers within the spraying range of the spraying assembly, the convex rings on the thin rollers keep the silicon wafers at a distance from the thin rollers, which can reduce the contact area between the transmission rollers and the back surface of the silicon wafers when spraying the silicon wafers, thereby reducing the adhesion of residual water to the back surface of the passing silicon wafers and reducing the impact on the acid bath concentration.

[0015] Compared with the continuous spraying in the prior art, by the cooperation of the proximity switch and the control valve in the present utility model, spraying can be carried out only for a period of time after the silicon wafer passes the proximity switch, ensuring that the silicon wafer stops after receiving sufficient spraying, improving the utilization efficiency and reducing the waste of water.

[0016] The outer diameter of the convex ring of the present utility model is the same as the diameter of the thick roller, which can keep the transmission of the silicon wafers stable. Description of the Drawings

[0017] Figure 1 It is a schematic side view of the structure of the spraying assembly in Embodiment 1 of the present utility model.

[0018] Figure 2 It is a schematic top view of the structure of the conveying roller in Embodiment 1 of the present utility model.

[0019] Figure 3 It is a schematic top view of the positional relationship between the spray pipe and the proximity switch in Embodiment 1 of the present utility model.

[0020] Figure 4 Partial enlarged side sectional view of the spray pipe structure of Embodiment 1 of the present utility model.

[0021] Figure 5 Partial enlarged side sectional view of the fine roller structure of Embodiment 2 of the present utility model.

[0022] In the figure, 1 - roller frame, 2 - spray assembly, 3 - coarse roller, 4 - fine roller, 5 - convex ring, 6 - spray pipe, 7 - water pipe, 8 - water tank, 9 - flow valve, 10 - control valve, 11 - partition board, 12 - spray cavity, 13 - proximity switch, 14 - arc-shaped protrusion, 15 - flow meter, 16 - water pipe connection port, 17 - spray hole. Detailed implementation manners

[0023] The present utility model will be further illustrated below in conjunction with the accompanying drawings and specific embodiments. Embodiment

[0024] Combined with Figures 1 to 4 It can be known that a conveying and spraying device for silicon wafer BSG removal includes a roller frame 1, multiple conveying rollers arranged at intervals along the silicon wafer conveying direction inside the roller frame 1, a spray assembly 2 transversely arranged above the roller frame 1, among the multiple conveying rollers, there are a coarse roller 3 and a fine roller 4 located within the spraying range of the spray assembly 2, multiple convex rings 5 are coaxially arranged at intervals on the fine roller 4, and the outer diameter of the convex ring 5 is the same as the diameter of the coarse roller 3.

[0025] The spray assembly 2 includes a spray pipe 6 transversely arranged above the roller frame 1, the spray pipe 6 is connected to a water tank 8 through a water pipe 7 above, and a flow valve 9 and a control valve 10 are arranged on the water pipe 7. The spray pipe 6 is a conventional spray pipe in the prior art, and it is provided with a water pipe connection port 16 for connecting with the water pipe 7 and multiple spray holes 17 for spraying.

[0026] The surface of the convex ring 5 is covered with a hydrophobic coating. Preferably, the hydrophobic coating is made of polytetrafluoroethylene or silicone resin material.

[0027] Multiple water pipes 7 are provided, arranged at intervals between the spray pipe 6 and the water tank 8, multiple partition boards 11 are arranged inside the spray pipe 6 and divide its interior into multiple spray cavities 12 corresponding to the number of water pipes 7. The control valve 10 is an electromagnetic valve, and a proximity switch 13 for detecting the approach of the silicon wafer is arranged on the roller frame 1, and the proximity switch 13 is electrically connected to the electromagnetic valve.

[0028] Generally, multiple silicon wafers are conveyed in the same row on the conveying rollers. By providing multiple water pipes 7, the present utility model can correspond to each silicon wafer in the same row of silicon wafers. Preferably, the number of proximity switches 13 is the same as the number of water pipes 7. When the proximity switch 13 detects that a silicon wafer passes below it, it controls the corresponding solenoid valve to start, and then controls the spray chamber 12 corresponding to the silicon wafer to spray for a period of time, which can achieve local spraying of a single silicon wafer, and compared with continuous spraying in the prior art, it improves the utilization efficiency and reduces water waste.

[0029] A flow meter 15 is provided on the water pipe 7. Preferably, a manual control valve is also provided on the water pipe 7, which can stop the water flow in the water pipe 7 through the manual control valve when the solenoid valve 10 fails.

[0030] At least three thin rollers 4 are provided. Preferably, five thin rollers 4 are provided. Embodiment

[0031] Combined with Figure 5 It can be seen that in this embodiment, compared with Embodiment 1, the structure of the convex ring 5 is further improved:

[0032] A ring-shaped arc-shaped protrusion 14 is provided on the outer periphery of the convex ring 5. The cross-section of the arc-shaped protrusion 14 is hemispherical, and the diameter of the hemisphere is the same as the thickness of the convex ring 5. The surfaces of the convex ring 5 and the arc-shaped protrusion 14 are covered with a hydrophobic coating.

[0033] By providing the arc-shaped protrusion 14 in this embodiment, the contact with the surface of the silicon wafer can be further reduced, thereby reducing the water adhering to the back of the silicon wafer, and the arc surface of the arc-shaped protrusion can guide the water to flow away, reducing water residue.

[0034] In addition, this embodiment is exactly the same as Embodiment 1, and will not be elaborated here.

[0035] The working principle of a conveying and spraying device for removing BSG from silicon wafers provided by the utility model is as follows: During use, when the proximity switch 13 detects that a silicon wafer passes below it, it controls the corresponding solenoid valve to start, and then controls the spray chamber 12 corresponding to the silicon wafer to spray for a period of time. The convex ring 5 on the thin roller 4 keeps the silicon wafer at a distance from the thin roller 4, which can reduce the contact area between the transmission roller and the back of the silicon wafer when spraying the silicon wafer, thereby reducing the residual water adhering to the back of the passing silicon wafer and reducing the influence on the acid tank concentration.

[0036] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be equally included in the scope of patent protection of the present utility model.

Claims

1. A conveying and spraying device for removing BSG from silicon wafers, characterized in that: The invention comprises a roller frame (1), wherein a plurality of conveying rollers are arranged at intervals in the roller frame (1) along the conveying direction of silicon wafers, a spray assembly (2) is arranged transversely above the roller frame (1), the plurality of conveying rollers comprise a coarse roller (3) and a fine roller (4) located within the spraying range of the spray assembly (2), the fine roller (4) having a plurality of convex rings (5) coaxially arranged at intervals, the outer diameter of the convex ring (5) being the same as the diameter of the coarse roller (3).

2. The conveying and spraying device for removing BSG from silicon wafers according to claim 1, characterized in that: The spray assembly (2) comprises a spray pipe (6) arranged transversely above the roller frame (1); a water tank (8) is connected to the spray pipe (6) via a water pipe (7); and a flow valve (9) and a control valve (10) are provided on the water pipe (7).

3. The conveying and spraying device for removing BSG from silicon wafers according to claim 2, characterized in that: A plurality of water pipes (7) are provided and arranged at intervals between the spray pipe (6) and the water tank (8); a plurality of partitions (11) are provided inside the spray pipe (6) to divide the interior of the spray pipe (6) into a plurality of spray chambers (12) corresponding to the number of water pipes (7).

4. The conveying and spraying device for removing BSG from silicon wafers according to claim 1, characterized in that: The surface of the convex ring (5) is covered with a hydrophobic coating.

5. The conveying and spraying device for removing BSG from silicon wafers according to claim 2, characterized in that: The control valve (10) is a solenoid valve, and a proximity switch (13) for detecting the approach of a silicon wafer is provided on the roller frame (1), and the proximity switch (13) is electrically connected to the solenoid valve.

6. The conveying and spraying device for removing BSG from silicon wafers according to claim 1, characterized in that: An annular arc-shaped protrusion (14) is provided on the outer periphery of the convex ring (5); the cross section of the arc-shaped protrusion (14) is hemispherical, and the diameter of the hemispherical shape is the same as the thickness of the convex ring (5).

7. The conveying and spraying device for removing BSG from silicon wafers according to claim 2, characterized in that: The water pipe (7) is provided with a flow meter (15).

8. The conveying and spraying device for removing BSG from silicon wafers according to claim 1, characterized in that: The fine rollers (4) are provided with at least three.

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