Dry etching device
The problems of Topcon solar cell winding plating and Poly Finger technology amorphous silicon removal are solved through dry etching device, achieving efficient etching and environmental protection and energy saving, and reducing production costs.
Patent Information
- Application Number
- CN202421927564.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-08
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2034-08-08
AI Technical Summary
In the prior art, the winding removal of Topcon solar cells and the amorphous silicon removal of Poly Finger technology are difficult to be efficiently performed. The wet etching method is not suitable for large-scale production and is costly. The dry etching device lacks an effective solution.
A dry etching device is designed, including a reaction chamber, a silicon wafer conveying roller, an etching gas inlet and an exhaust port, equipped with a heater and a nitrogen isolation screen, etching is performed using a mixture of N2 and F2 gases, and combined with a preheating chamber and a waste gas treatment system, winding removal and amorphous silicon removal are achieved.
The topcon technology winding removal and Poly Finger technology are realized, the back surface thinning is reduced, the etching speed is fast, the operating cost is reduced, and the environmental protection and energy-saving effect is achieved through the exhaust gas treatment system.
Smart Images
Figure CN223167441U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of solar cells, and specifically relates to a dry etching device. Background Art
[0002] Topcon is a tunneling oxide passivated contact (Tunnel Oxide Passivated Contact) solar cell technology based on the principle of selective carriers. Its cell structure is an N-type silicon substrate cell. An ultrathin silicon oxide layer is prepared on the back of the cell, and then a doped silicon thin layer is deposited. The two together form a passivated contact structure, effectively reducing surface recombination and metal contact recombination, providing more room for further improvement of the conversion efficiency of N-PERT cells. However, since the growth of the key process polysilicon layer in this technology mainly uses low-pressure chemical vapor deposition or plasma chemical vapor deposition, during the deposition process, inevitable positive plating occurs to form useless coatings. The industry generally uses an alkaline solution chemical method to remove the useless coatings, but its etching rate is low and the potential process reproducibility is poor. In addition, considering the relevant costs of process consumables and emission reduction processes, the wet etching chemical method for removing plating is not suitable for large-scale production.
[0003] In addition, the Poly Finger technology refers to the thinning or even absence of Poly in the non-grid line area. The mechanism of efficiency improvement of this technology is to reduce the parasitic absorption of the Poly layer in the non-grid line area, and the retention mechanism of Poly in the grid line area is to reduce metal recombination; therefore, it is necessary to etch away the useless amorphous silicon. Currently, no relevant device for removing amorphous silicon in Poly Finger by dry method has been found. Summary of the Utility Model
[0004] To solve the problems in the above background art, the utility model provides a dry etching device, which can realize dry removal of Poly plating or back thinning of Poly Finger, and can reduce the operation cost of the factory.
[0005] The utility model adopts the following technical solutions:
[0006] A dry etching device includes a reaction chamber;
[0007] A silicon wafer conveying roller path is arranged in the reaction chamber; an etching gas inlet is arranged above the silicon wafer conveying roller path on the reaction chamber, and an exhaust port is arranged below the silicon wafer conveying roller path;
[0008] At least one first heater is arranged in the reaction chamber, and the first heater heats the temperature in the reaction chamber to the reaction temperature;
[0009] The reaction chamber is communicated with an exhaust gas treatment chamber through the exhaust port.
[0010] Further, there are at least two first heaters, and the at least two first heaters are respectively distributed above and below the silicon wafer conveying roller path.
[0011] Further, at least two first heaters are symmetrically arranged around the position of the etching gas inlet. An air distribution plate is arranged below the etching gas inlet and the first heaters, and a plurality of through air holes are formed in the air distribution plate.
[0012] Further, there are two exhaust ports, namely a first exhaust port and a second exhaust port. The first exhaust port is close to the inlet of the reaction chamber, and the second exhaust port is close to the outlet of the reaction chamber. The etching gas inlet is located between the inlet and the outlet of the reaction chamber.
[0013] Further, nitrogen isolation curtains are arranged at the positions where the inlets and outlets of the reaction chamber are opposite to the exhaust ports.
[0014] Further, the etching gas enters the reaction chamber from the etching gas inlet. The etching gas is N2 and F2, and the concentration of F2 is 8%-20%.
[0015] Further, a preheating chamber is communicated with the inlet of the reaction chamber, and at least one second heater is arranged in the preheating chamber.
[0016] Further, the exhaust port is connected to an exhaust gas treatment chamber through an exhaust gas pipeline. A spray head is installed at the top of the exhaust gas treatment chamber, and the spray head is connected to an external water source.
[0017] Further, an exhaust gas outlet and a waste water outlet are formed in the exhaust gas treatment chamber. The exhaust gas outlet is connected to an acid discharge pipeline, and the waste water outlet is connected to a waste discharge pipeline.
[0018] Further, a suction fan is arranged at the exhaust port.
[0019] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0020] (1) The dry etching device of the present application is provided with a silicon wafer conveying roller path in the reaction chamber. An etching gas inlet is arranged above the silicon wafer conveying roller path, and an exhaust port is arranged below. At the same time, a first heater is arranged in the reaction chamber to keep the temperature in the reaction chamber at the reaction temperature. When the silicon wafer enters the reaction chamber and the temperature reaches the reaction temperature, it reacts with the etching gas entering from the etching gas inlet. The gas after the reaction is discharged from the exhaust port to the exhaust gas treatment chamber. This device can be applied to the removal of wrap-around plating in Topcon technology or the back thinning of Poly Finger technology, and the entire wrap-around plating removal process or the back thinning process of Poly Finger adopts dry technology, with a simple method, fast etching speed, and reduced operating costs.
[0021] (2) The dry etching device of the present application is connected with a preheating chamber at the inlet of the reaction chamber. At least one second heater is provided in the preheating chamber. The preheating chamber belongs to the preheating area in advance. The silicon wafer is preheated in the preheating chamber before entering the reaction chamber, so that the silicon wafer reaches the reaction temperature in advance, and then enters the reaction chamber to react with the etching gas, reducing the temperature rise time of the silicon wafer and improving the etching efficiency.
[0022] (3) The exhaust port of the dry etching device of the present application is connected to the waste gas treatment chamber through a waste gas pipeline, and the tail gas is treated by spraying. The treated waste gas is connected to the acid discharge pipeline, and the waste water is connected to the waste discharge pipeline, achieving the effects of energy saving and environmental protection. Description of the Drawings
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0024] Figure 1 It is the overall structure diagram of the dry etching device of the present invention;
[0025] Wherein: 1 - reaction chamber, 2 - silicon wafer conveying roller path, 3 - etching gas inlet, 4 - exhaust port, 41 - first exhaust port, 42 - second exhaust port, 5 - first heater, 6 - gas distribution plate, 7 - waste gas treatment chamber, 8 - first nitrogen isolation curtain, 9 - second nitrogen isolation curtain, 10 - preheating chamber, 11 - second heater, 12 - waste gas pipeline, 13 - acid discharge pipeline, 14 - waste discharge pipeline, 15 - silicon wafer. Detailed Embodiments
[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.
[0027] The following will be combined with the attached Figure 1 And specific embodiments to elaborate on the present invention in detail.
[0028] As Figure 1As shown, the utility model provides a dry etching device, which can be applied to the wrap-around plating removal of Topcon technology or the back thinning of Poly Finger technology. The dry etching device provided in the embodiment of the present application includes a reaction chamber 1, and the processes of wrap-around plating removal and amorphous silicon removal are both carried out in the reaction chamber 1; a silicon wafer conveying roller 2 is provided in the reaction chamber 1, which is used to continuously convey silicon wafers into the reaction chamber 1 and at the same time transport the silicon wafers that have completed the reaction out; an etching gas inlet 3 is provided on the reaction chamber 1 above the silicon wafer conveying roller 2, and an exhaust port 4 is provided below the silicon wafer conveying roller 2; at least one first heater 5 is provided in the reaction chamber 1, and the first heater 5 heats the temperature in the reaction chamber 1 to the reaction temperature; the reaction chamber 1 is connected to the exhaust gas treatment chamber 7 through the exhaust port 4. It should be noted that the reaction temperature for removal of wrap-around plating or amorphous silicon is generally 200-250°C. The etching gas enters the reaction chamber 1 from the etching gas inlet 3 and reacts with the wrap-around plating on the front of the silicon wafer or the amorphous silicon on the back of the silicon wafer. The etching gas uses a mixed gas of N2 carrying F2, and the higher the concentration of F2, the faster the reaction rate. Under actual working conditions, the ratio of N2 and F2 can be selected according to the thickness of the wrap-around plating layer or amorphous silicon on the silicon wafer to complete the process of removing the wrap-around plating or Poly thinning within a predetermined time.
[0029] It is worth emphasizing again that the dry etching device of the present application can be used not only in the field of wrap-around plating removal of Topcon technology, but also in the field of amorphous silicon removal of Poly Finger technology (Poly Finger backside thinning technology), with a wider range of applications, which can reduce the operating costs of the factory.
[0030] In the embodiment of the present application, there are at least two first heaters 5, and at least two first heaters 5 are respectively distributed above and below the silicon wafer conveyor roller 2. In other words, first heaters 5 must be installed above and below the silicon wafer conveyor roller 2 to output heat outward in all directions, thereby achieving temperature uniformity and stability in the reaction chamber 1. Optionally, the first heaters 5 are distributed all over the inner wall of the reaction chamber 1, and the heat output from the first heaters 5 is evenly distributed throughout the reaction chamber 1, so that the reaction temperature is always maintained between 200-250°C.
[0031] Specifically, at least two first heaters 5 are symmetrically arranged around the position of the etching gas inlet 3, and the heat output by the first heaters 5 first contacts the etching gas, rapidly increasing the temperature of the etching gas, which can accelerate the etching rate. An air distribution plate 6 is arranged below the etching gas inlet 3 and the first heaters 5 around the etching gas inlet. A plurality of through air holes are formed in the air distribution plate 6, and the air distribution plate 6 extends from the inlet to the outlet of the reaction chamber 1, that is, the silicon wafer conveying roller path 2 entering the reaction chamber 1 is located directly below the air distribution plate 6. It can be known that a plurality of silicon wafers 15 are arranged along the conveying direction on the silicon wafer conveying roller path 2. To ensure that each silicon wafer 15 can react with the etching gas, the etching gas needs to be evenly diffused in the reaction chamber 1. Therefore, by setting the air distribution plate 6, the uniform diffusion of the etching gas is realized, further ensuring that each silicon wafer reacts completely with the etching gas and improving the etching quality.
[0032] In a specific embodiment, there are two exhaust ports 4, namely a first exhaust port 41 and a second exhaust port 42. The first exhaust port 41 is close to the inlet of the reaction chamber 1, and the second exhaust port 42 is close to the outlet of the reaction chamber 1. The etching gas inlet 3 is located between the inlet and the outlet of the reaction chamber 1. After the etching gas enters the reaction chamber 1 from the etching gas inlet 3, it reacts with the silicon wafers on the silicon wafer conveying roller path 2. The tail gas after the reaction diffuses to both sides and is discharged to the waste gas treatment chamber 7 from the first exhaust port 41 and the second exhaust port 42. The waste gas treatment chamber 7 is used to treat and recycle the waste gas after the reaction.
[0033] In some embodiments, the reaction chamber 1 is a cylindrical structure that is closed on all sides and has openings at the front and rear ends. The etching gas inlet 3 is opened on the side wall of the cylindrical structure and is communicated with the outside atmosphere. The first heaters 5 are installed on the inner wall of the cylindrical structure.
[0034] Specifically, nitrogen isolation curtains are arranged at the positions of the inlet and outlet of the reaction chamber 1 that are opposite to the exhaust port 4. That is, the first nitrogen isolation curtain 8 is opposite to the first exhaust port 41, and the second nitrogen isolation curtain 9 is opposite to the second exhaust port 42. During the reaction process, nitrogen is continuously transported from the first nitrogen isolation curtain 8 to the first exhaust port 41 and from the second nitrogen isolation curtain 9 to the second exhaust port 42 to limit the etching gas in the reaction chamber 1 and prevent leakage. The nitrogen ejected from the first nitrogen isolation curtain 8 seals the inlet of the reaction chamber 1, and the nitrogen ejected from the second nitrogen isolation curtain 9 seals the outlet of the reaction chamber 1, preventing the etching gas from leaking out of the inlet and outlet of the reaction chamber 1 and ensuring the utilization rate of the etching gas.
[0035] In the embodiments of the present application, the etching gas enters the reaction chamber 1 from the etching gas inlet 3. The etching gas is N2 and F2, and the concentration of F2 is 8%-20%. Preferably, the concentration of F2 is 10%, which can meet the normal etching rate. The higher the concentration of F2, the faster the reaction rate. Before using this device, those skilled in the art can set the concentration of F2 according to the requirements of the silicon wafer to achieve the desired etching efficiency.
[0036] In some embodiments, a preheating chamber 10 is connected to the inlet of the reaction chamber 1. At least one second heater 11 is provided in the preheating chamber 10. The silicon wafer conveying roller path 2 extends into the preheating chamber 10. The silicon wafer is loaded from the inlet of the preheating chamber 10 and passes through the preheating chamber 10 for preheating before the reaction, so that the temperature of the silicon wafer reaches the reaction temperature before entering the reaction chamber 1, further accelerating the etching rate. It should be noted that when the preheating chamber 10 is provided, the preheating chamber 10 and the reaction chamber 1 are integrally formed reactors. The first nitrogen isolation curtain 8 and the first exhaust port 41 are opened between the preheating chamber 10 and the reaction chamber 1, that is, on the side wall of the reactor, as long as the etching gas can be blocked in the reaction chamber 1.
[0037] When the etching device of the present application is used to remove the wrap plating on the silicon wafer, the silicon wafer 15 on the ceramic conveying roller path 2 is set with the front side facing up; when used in the Poly Finger back thinning technology, the silicon wafer 15 on the ceramic conveying roller path 2 is set with the back side facing up.
[0038] Furthermore, the first exhaust port 41 and the second exhaust port 42 are connected to the waste gas treatment chamber 7 through the waste gas pipeline 12. A spray head is installed on the top of the waste gas treatment chamber 7, and the spray head is connected to an external water source. The waste gas treatment chamber 7 is provided with a waste gas outlet and a waste water outlet. The waste gas outlet is connected to the acid discharge pipeline 13 and connected to the acid discharge plant through the acid discharge pipeline 13. The waste water outlet is connected to the waste discharge pipeline 14 and connected to the waste discharge plant through the waste discharge pipeline 14. The tail gas is treated by spraying. The waste water generated by the reaction is acidic and is connected to the waste discharge pipeline 14 through the waste water outlet for neutralization treatment at the plant end, and the waste gas is discharged from the acid discharge pipeline 13.
[0039] Furthermore, a suction fan is provided at the exhaust port 4. The suction fan provides a certain wind speed to discharge the waste gas to the waste gas treatment chamber 7. Usually, the wind speed is preferably above 6m / s.
[0040] The above further describes the present invention with the help of specific embodiments. However, it should be understood that the specific description here should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above embodiments after reading this specification all fall within the scope protected by the present invention.
Claims
1. A dry etching apparatus, characterized in that, It includes a reaction chamber; A wafer conveying roller path is provided inside the reaction chamber; an etching gas inlet is provided above the wafer conveying roller path on the reaction chamber, and an exhaust port is provided below the wafer conveying roller path; At least one first heater is provided inside the reaction chamber, and the first heater heats the temperature inside the reaction chamber to the reaction temperature; The reaction chamber is communicated with an exhaust gas treatment chamber through the exhaust port.
2. The dry etching apparatus according to claim 1, wherein There are at least two first heaters, and at least two first heaters are respectively distributed above and below the wafer conveying roller path.
3. The dry etching apparatus according to claim 1, characterized in that, At least two first heaters are symmetrically arranged around the position of the etching gas inlet, an air distribution plate is arranged below the etching gas inlet and the first heater, and a plurality of through air holes are formed in the air distribution plate.
4. The dry etching apparatus according to claim 1, wherein There are two exhaust ports, namely a first exhaust port and a second exhaust port. The first exhaust port is close to the inlet of the reaction chamber, the second exhaust port is close to the outlet of the reaction chamber, and the etching gas inlet is located between the inlet and the outlet of the reaction chamber.
5. The dry etching apparatus according to claim 2, characterized in that Nitrogen isolation curtains are arranged at the positions opposite to the exhaust ports at the inlet and outlet of the reaction chamber.
6. The dry etching apparatus according to claim 1, characterized in that The etching gas enters the reaction chamber from the etching gas inlet. The etching gas is N2 and F2, and the concentration of F2 is 8%-20%.
7. The dry etching apparatus according to claim 1, wherein A preheating chamber is communicated with the inlet of the reaction chamber, and at least one second heater is provided inside the preheating chamber.
8. The dry etching apparatus according to claim 1, wherein The exhaust port is connected to the exhaust gas treatment chamber through an exhaust gas pipeline, and a spray head is installed on the top of the exhaust gas treatment chamber, and the spray head is connected to an external water source.
9. The dry etching apparatus according to claim 8, wherein An exhaust gas outlet and a waste water outlet are formed on the exhaust gas treatment chamber. The exhaust gas outlet is connected to an acid discharge pipeline, and the waste water outlet is connected to a waste discharge pipeline.
10. The dry etching apparatus according to claim 1, wherein A suction fan is arranged at the exhaust port.