Silicon wafer gettering device

Abstract

The utility model discloses a silicon wafer gettering device, which relates to the field of solar cell manufacturing, and comprises a roller type coating mechanism and a heating mechanism, the heating mechanism comprises a heating chamber and a roller conveyor, the heating chamber forms a heating cavity, the roller conveyor is arranged in the heating cavity, the heating chamber forms a feed port, the feed port is communicated with the heating cavity, and the roller conveyor is arranged in the heating cavity. The opening direction of the feeding port is consistent with the conveying direction of the roller conveyor, the roller type coating mechanism is located on the side, away from the roller conveyor, of the feeding port, and the roller type coating mechanism is used for making double-face contact with a silicon wafer to be subjected to gettering and conveying the silicon wafer to be subjected to gettering to the roller conveyor. The utility model has the advantages of reducing the damage of the silicon wafer and improving the gettering effect.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cell manufacturing, and particularly relates to a silicon wafer gettering device. Background Art

[0002] Gettering is a method widely used in the semiconductor field to reduce impurities in silicon wafers. The gettering methods include phosphorus diffusion gettering, boron diffusion gettering, aluminum gettering, defect gettering, and interface gettering, etc. Comparatively speaking, phosphorus diffusion gettering is a gettering method that is convenient for industrial application and has a good gettering effect. For example, in the process of PERC solar cells, phosphorus diffusion simultaneously serves the purpose of fabricating a PN junction and improving the minority carrier lifetime.

[0003] Currently, the phosphorus diffusion gettering method is usually implemented by a tube-type phosphorus diffusion device. The tube-type phosphorus diffusion device has high cleanliness, good gettering effect, mature process, and high equipment cost performance. However, in heterojunction solar cells, since the thickness of the target silicon wafer will drop to about 100 microns, the wafer loading and unloading method of the tube-type phosphorus diffusion device will cause a relatively high risk of fragmentation. Summary of the Utility Model

[0004] The utility model aims to solve one of the technical problems in the related technologies to a certain extent. For this purpose, the utility model provides a silicon wafer gettering device, which has the advantages of reducing silicon wafer damage and improving the gettering effect.

[0005] In order to achieve the above object, the utility model adopts the following technical scheme:

[0006] A silicon wafer gettering device includes a roll coating mechanism and a heating mechanism. The heating mechanism includes a heating chamber and a roller conveyor. The heating chamber forms a heating cavity. The roller conveyor is arranged in the heating cavity. The heating chamber forms a feed inlet, and the feed inlet communicates with the heating cavity. The opening direction of the feed inlet is consistent with the conveying direction of the roller conveyor. The roll coating mechanism is located on the side of the feed inlet away from the roller conveyor, and the roll coating mechanism is used to contact both sides of the silicon wafer to be gettered and convey the silicon wafer to be gettered onto the roller conveyor.

[0007] The gettering phosphorus source solution is coated on both sides of the silicon wafer to be gettered through the roll coating mechanism. After coating, the silicon wafer to be gettered is conveyed to the roller conveyor, and annealing treatment is performed on the silicon wafer to be gettered coated with the gettering phosphorus source solution in the heating cavity with temperature rising, so that a phosphorus gettering layer is generated on the silicon wafer to be gettered. The metal impurities in the silicon wafer to be gettered continuously move to the phosphorus gettering layer on the surface in a high-temperature environment, thereby effectively reducing the impurity concentration of the silicon wafer to be gettered and improving the gettering effect. Moreover, the silicon wafer to be gettered is conveyed into the heating cavity through the roll coating mechanism, without the need for the wafer loading and unloading method, reducing the damage to the silicon wafer.

[0008] Optionally, the roll coating mechanism includes a liquid supply component, a mounting bracket, a first roller, and a plurality of second rollers; the liquid supply component is used to add the impurity-absorbing phosphorus source solution to the surface of the silicon wafer to be impurity-absorbed.

[0009] A plurality of the second rollers are rotatably arranged on the mounting bracket at intervals along the conveying direction of the roller conveyor. The first roller is arranged on the mounting bracket, and the first roller is located on the side of the plurality of second rollers away from the mounting bracket, and the first roller is opposite to one of the second rollers.

[0010] Optionally, the liquid supply component includes a first liquid storage tank, a liquid supply pump, and a drip tube. The liquid supply pump is connected between the drip tube and the first liquid storage tank, and the drip tube is located on the side of the second roller away from the mounting bracket.

[0011] Optionally, the roll coating mechanism further includes a second liquid storage tank. The second liquid storage tank is arranged on the mounting bracket, and at least a part of the second roller extends into the second liquid storage tank.

[0012] Optionally, the drip tube is located on the side of the first roller away from the mounting bracket, and the drip tube is opposite to the first roller.

[0013] Optionally, the heating mechanism further includes a plurality of heating tubes, and the plurality of heating tubes are arranged at intervals on the top of the heating chamber.

[0014] Optionally, the heating mechanism further includes a plurality of ultraviolet tubes, and the plurality of ultraviolet tubes are arranged at intervals on the top of the heating chamber, and the ultraviolet tubes are arranged alternately with the heating tubes.

[0015] Optionally, the heating mechanism further includes at least one air supply pipe. The air supply pipe is arranged on the inner wall of the heating chamber. One end of the air supply pipe is communicated with the heating chamber, and the other end of the air supply pipe is used to be communicated with an external air supply device.

[0016] Optionally, the heating mechanism further includes a heat insulation layer, and the heat insulation layer is attached to the inner wall of the heating chamber.

[0017] Optionally, the heating mechanism further includes a baffle. The edge of the baffle is connected to the inner wall of the heating chamber to divide the heating chamber into a first heating chamber and a second heating chamber; the baffle is formed with a through hole penetrating the baffle in the thickness direction, and the first heating chamber and the second heating chamber are communicated through the through hole.

[0018] These features and advantages of the present utility model will be disclosed in detail in the following specific embodiments and the accompanying drawings. The best embodiments or means of the present utility model will be elaborately presented in combination with the accompanying drawings, but it is not a limitation to the technical solution of the present utility model. In addition, these features, elements, and structures appear in multiple in each of the following texts and drawings, and different symbols or numbers are marked for convenience of representation, but they all represent components with the same or similar structures or functions. Description of the Drawings

[0019] The present utility model will be further described below in conjunction with the accompanying drawings:

[0020] Figure 1 It is a schematic structural diagram of a device according to an embodiment of the present utility model.

[0021] Figure 2 It is a schematic structural diagram of a device according to another embodiment of the present utility model.

[0022] Among them, 10, heating mechanism; 11, heating chamber; 11a, heating cavity; 11b, feed inlet; 12, roller conveyor; 13, heating lamp tube; 14, ultraviolet lamp tube; 15, air supply pipe; 16, heat insulation layer; 17, baffle; 17a, through hole; 20, roller coating mechanism; 21, first liquid storage tank; 22, first roller; 23, second roller; 24, second liquid storage tank; 25, drip tube; 26, liquid supply pump; 27, regulating valve; 30, silicon wafer to be impurity-removed. Specific Embodiments

[0023] The embodiments of the present utility model will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. Based on the embodiments in the embodiments, it is intended to explain the present utility model and should not be construed as a limitation to the present utility model.

[0024] As used in this specification, the phrase "in one embodiment" or "example" or "instance" means that the specific features, structures, or characteristics described in connection with the embodiment itself may be included in at least one embodiment of the present patent disclosure. The appearances of the phrase "in one embodiment" at various positions in the specification do not necessarily refer to the same embodiment.

[0025] This embodiment provides a silicon wafer impurity-removing device, as Figure 1As shown in the figure, it includes a roll coating mechanism 20 and a heating mechanism 10. The heating mechanism 10 includes a heating chamber 11 and a roller conveyor 12. The heating chamber 11 forms a heating cavity 11a. The roller conveyor 12 is arranged in the heating cavity 11a. The heating chamber 11 forms a feed inlet 11b. The feed inlet 11b is communicated with the heating cavity 11a. The opening direction of the feed inlet 11b is consistent with the conveying direction of the roller conveyor 12. The roll coating mechanism 20 is located on the side of the feed inlet 11b away from the roller conveyor 12. The roll coating mechanism 20 is used for double-sided contact with the silicon wafer to be gettered 30 and conveying the silicon wafer to be gettered 30 onto the roller conveyor 12.

[0026] The gettering phosphorus source solution is coated on both sides of the silicon wafer to be gettered 30 through the roll coating mechanism 20. After coating, the silicon wafer to be gettered 30 is conveyed to the roller conveyor 12. The silicon wafer to be gettered 30 coated with the gettering phosphorus source solution is annealed in the heated heating cavity 11a at an elevated temperature so that the silicon wafer to be gettered 30 generates a phosphorus gettering layer. The metal impurities in the silicon wafer to be gettered 30 continuously move to the phosphorus gettering layer on the surface in a high-temperature environment, thereby effectively reducing the impurity concentration of the silicon wafer to be gettered 30 and improving the gettering effect. Moreover, the silicon wafer to be gettered 30 is conveyed into the heating cavity 11a through the roll coating mechanism 20, without the need for the wafer suction method for loading and unloading, reducing the damage to the silicon wafer. It should be noted that the inner wall material of the heating chamber 11 is any one of quartz, high-purity ceramics or glass-ceramics, to prevent the silicon wafer to be gettered 30 from adsorbing external impurities. Similarly, in order to avoid introducing new metal impurities, the roller conveyor is preferably a ceramic roller conveyor.

[0027] Optionally, the roll coating mechanism includes a liquid supply component, a mounting rack (not shown in the figure), a first roller 22, and a plurality of second rollers 23; the liquid supply component is used for adding the gettering phosphorus source solution to the surface of the silicon wafer to be gettered 30;

[0028] A plurality of second rollers 23 are rotatably arranged on the mounting rack at intervals along the conveying direction of the roller conveyor 12. The first roller 22 is arranged on the mounting rack, and the first roller 22 is located on the side of the plurality of second rollers 23 away from the mounting rack. The first roller 22 faces one of the second rollers 23.

[0029] In the present invention, the structure of the liquid supply component is not specifically limited as long as the liquid supply component can directly or indirectly add the gettering phosphorus source coating solution to the surface of the silicon wafer to be gettered 30. Optionally, the liquid supply component includes a first liquid storage tank 21, a liquid supply pump 26, and a drip tube 25. The liquid supply pump 26 is connected between the drip tube 25 and the first liquid storage tank 21. The drip tube 25 is located on the side of the second roller 23 away from the mounting rack.

[0030] It should be noted that the first liquid storage tank 21 is used to hold the impurity-absorbing phosphorus source solution. The impurity-absorbing phosphorus source solution in the first liquid storage tank 21 is transported to the drip tube 25 through the liquid supply pump 26, and the impurity-absorbing phosphorus source solution is dripped onto the surface of the silicon wafer 30 to be impurity-absorbed through the drip tube 25. The silicon wafer 30 to be impurity-absorbed can be attached between the first roller 22 and the second roller 23. The first roller 22 and the second roller 23 rotate relatively. Under the action of the first roller 22, the impurity-absorbing phosphorus source solution dripped onto the surface of the silicon wafer 30 to be impurity-absorbed can be evenly coated on the silicon wafer 30 to be impurity-absorbed. Thus, when the silicon wafer 30 to be impurity-absorbed is annealed subsequently, a phosphorus impurity-absorbing layer can be evenly formed on the surface of the silicon wafer 30 to be impurity-absorbed, improving the impurity-absorbing effect. Moreover, driven by the first roller 22 and the second roller 23, the silicon wafer 30 to be impurity-absorbed can be transported to the roller conveyor 12. It can be understood that a regulating valve 27 is provided on the drip tube 25, and the regulating valve 27 is used to control the opening and closing of the drip tube 25 and adjust the drip rate of the drip tube 25.

[0031] In an optional embodiment, the roll coating mechanism 20 further includes a second liquid storage tank 24. The second liquid storage tank 24 is arranged on the mounting frame, and at least a part of the second roller 23 extends into the second liquid storage tank 24.

[0032] By providing the second liquid storage tank 24, a part of the second roller 23 is immersed in the impurity-absorbing phosphorus source solution contained in the second liquid storage tank 24. In this way, during the rotation of the second roller 23, the impurity-absorbing phosphorus source solution can be coated on one side of the silicon wafer 30 to be impurity-absorbed facing the second roller 23. With the cooperation of the first roller 22 and the second roller 23, the impurity-absorbing phosphorus source solution can be coated on both sides of the silicon wafer 30 to be impurity-absorbed.

[0033] In the present utility model, there is no special limitation on the materials of the first roller 22 and the second roller 23, as long as the first roller 22 and the second roller 23 can coat the impurity-absorbing phosphorus source solution on the silicon wafer 30 to be impurity-absorbed. For example, the materials of the first roller 22 and the second roller 23 are any one of polyethylene, polyvinyl chloride, polypropylene, polystyrene, polyoxymethylene, polyamide, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polymethyl methacrylate, acrylonitrile-styrene copolymer, polysulfone, polyimide, polyphenylene sulfide, polyethersulfone, polyarylate, polyamide-imide, polyphenylene ester, polytetrafluoroethylene, and polyvinylidene fluoride.

[0034] Optionally, as Figure 2 shown, the drip tube 25 is located on the side of the first roller 22 away from the mounting frame, and the drip tube 25 is opposite to the first roller 22.

[0035] It can be understood that the dropper 25 is arranged above the first roller 22 and can drip the impurity-absorbing phosphorus source solution onto the first roller 22. After the first roller 22 is wetted, by contacting with the silicon wafer 30 to be impurity-absorbed, the impurity-absorbing phosphorus source solution is coated on the silicon wafer 30 to be impurity-absorbed during the rotation process.

[0036] In an alternative embodiment, the heating mechanism 10 further includes a plurality of heating tubes 13, and the plurality of heating tubes 13 are arranged at intervals on the top of the heating chamber 11a.

[0037] By arranging the heating tubes 13, the heating chamber 11a is heated, so as to perform annealing impurity absorption treatment on the silicon wafer 30 to be impurity-absorbed located in the heating chamber 11a. In this embodiment, the type of the heating tubes 13 is not particularly limited, as long as the heating tubes 13 can raise the temperature of the heating chamber 11a to 600°C - 1000°C during operation.

[0038] In order to reduce the temperature difference at each part of the heating chamber 11a, preferably, the plurality of heating tubes 13 are evenly spaced and distributed on the top of the heating chamber 11a.

[0039] Optionally, the heating mechanism 10 further includes a plurality of ultraviolet tubes 14, the plurality of ultraviolet tubes 14 are arranged at intervals on the top of the heating chamber 11a, and the ultraviolet tubes 14 are arranged alternately with the heating tubes 13.

[0040] By arranging the ultraviolet tubes 14, the impurity absorption effect of the annealing impurity absorption treatment on the silicon wafer 30 to be impurity-absorbed is enhanced.

[0041] In an alternative embodiment, as Figure 1 and Figure 2 shown, the heating mechanism 10 further includes at least one air supply pipe 15, the air supply pipe 15 is arranged on the inner wall of the heating chamber 11a, one end of the air supply pipe 15 is communicated with the heating chamber 11a, and the other end of the air supply pipe 15 is used for communicating with an external air supply device.

[0042] Wherein, when performing annealing impurity absorption treatment on the silicon wafer 30 to be impurity-absorbed in the heating chamber 11a, the required gas is introduced into the heating chamber 11a through the air supply pipe 15 to enhance the impurity absorption effect, and the gas flow rate can be adjusted as needed. Since the working temperature of the heating chamber 11a is relatively high, it can be understood that the material of the air supply pipe 15 is a high-temperature resistant material.

[0043] Optionally, the heating mechanism 10 further includes a thermocouple (not shown in the figure), and the thermocouple is arranged on the inner wall of the heating chamber 11a.

[0044] By arranging the thermocouple, the temperature inside the heating chamber 11a is measured, so as to facilitate adjusting the heating tubes 13 according to the measured temperature, so that the temperature of the heating chamber 11a is within the temperature range of annealing impurity absorption.

[0045] In an alternative embodiment, the heating mechanism 10 further includes a heat insulation layer 16 which is attached to the inner wall of the heating chamber 11a.

[0046] By providing the heat insulation layer 16, heat loss due to heat conduction is reduced, improving the energy efficiency of the device.

[0047] Optionally, as Figure 1 shown, the heating mechanism 10 further includes a baffle 17. The edge of the baffle 17 is connected to the inner wall of the heating chamber 11a to divide the heating chamber 11a into a first heating chamber 11a and a second heating chamber 11a. The baffle 17 is formed with a through hole 17a that penetrates the baffle 17 in the thickness direction, and the first heating chamber 11a and the second heating chamber 11a are connected through the through hole 17a.

[0048] The baffle 17 divides the heating chamber 11a into a first heating chamber 11a and a second heating chamber 11a. Among them, the operating temperature of the first heating chamber 11a is higher than that of the second heating chamber 11a. The operating temperature range of the first heating chamber 11a is 800°C to 1000°C, and the operating temperature range of the second heating chamber 11a is 600°C to 950°C. The annealing and gettering treatment of the wafers to be gettered 30 is carried out at two temperatures, thereby effectively removing metal impurities in the wafers and improving the minority carrier lifetime of the wafers.

[0049] In this embodiment, the size and shape of the through hole 17a of the baffle 17 are not specifically limited, as long as the through hole 17a can pass the wafers to be gettered 30 placed on the roller conveyor 12.

[0050] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A silicon wafer gettering device, comprising a roller coating mechanism and a heating mechanism, wherein the heating mechanism comprises a heating chamber and a roller conveyor, wherein the heating chamber forms a heating cavity, and the roller conveyor is arranged in the heating cavity, wherein: The heating chamber is formed with a feed port, which is connected to the heating chamber. The opening direction of the feed port is consistent with the conveying direction of the roller conveyor. The roller coating mechanism is located on the side of the feed port away from the roller conveyor. The roller coating mechanism is used to contact with both sides of the silicon wafer to be gettered and convey the silicon wafer to be gettered to the roller conveyor.

2. The silicon wafer gettering device according to claim 1, characterized in that: The roller coating mechanism comprises a liquid supply component, a mounting frame, a first roller, and a plurality of second rollers; the liquid supply component is used to add a gettering phosphorus source solution to the surface of the silicon wafer to be gettered; A plurality of second rollers are rotatably arranged on the mounting frame at intervals along the conveying direction of the roller conveyor, the first roller is arranged on the mounting frame, and the first roller is located on the side of the plurality of second rollers away from the mounting frame, and the first roller is opposite to one of the second rollers.

3. The silicon wafer gettering device according to claim 2, characterized in that: The liquid supply assembly comprises a first liquid storage tank, a liquid supply pump and a liquid dropper, the liquid supply pump is connected between the liquid dropper and the first liquid storage tank, and the liquid dropper is located on a side of the second roller away from the mounting frame.

4. The silicon wafer gettering device according to claim 3, characterized in that: The roller coating mechanism further includes a second liquid storage tank, which is disposed on the mounting frame, and at least a portion of the second roller extends into the second liquid storage tank.

5. The silicon wafer gettering device according to claim 3, characterized in that: The drip tube is located at a side of the first roller away from the mounting frame, and the drip tube is opposite to the first roller.

6. The silicon wafer gettering device according to claim 1, characterized in that: The heating mechanism also includes a plurality of heating lamp tubes, and the plurality of heating lamp tubes are arranged at intervals on the top of the heating chamber.

7. The silicon wafer gettering device according to claim 6, characterized in that: The heating mechanism further comprises a plurality of ultraviolet lamp tubes, which are arranged at intervals on the top of the heating chamber, and the ultraviolet lamp tubes and the heating lamp tubes are arranged alternately.

8. The silicon wafer gettering device according to claim 1, characterized in that: The heating mechanism further comprises at least one air supply pipe, which is arranged on the inner wall of the heating chamber, one end of which is connected to the heating chamber, and the other end of which is connected to an external air supply device.

9. The silicon wafer gettering device according to claim 1, characterized in that: The heating mechanism also includes a heat-insulating layer, and the heat-insulating layer is in contact with the inner wall of the heating chamber.

10. The silicon wafer gettering device according to any one of claims 1 to 9, characterized in that: The heating mechanism also includes a baffle, the edge of which is connected to the inner wall of the heating chamber to separate the heating chamber into a first heating chamber and a second heating chamber; the baffle is formed with a through hole that penetrates the baffle along the thickness direction, and the first heating chamber and the second heating chamber are connected through the through hole.

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