CN210535682U

CN210535682U - TOPCon battery surface passivation equipment

Info

Publication number: CN210535682U
Application number: CN201921049522.5U
Authority: CN
Inventors: 吴晓松; 陈庆敏; 李建新; 李丙科
Original assignee: Wuxi Songyu Technology Co ltd
Current assignee: Wuxi Songyu Technology Co ltd
Priority date: 2019-07-08
Filing date: 2019-07-08
Publication date: 2020-05-15
Anticipated expiration: 2029-07-08

Abstract

The utility model discloses a TOPCon battery surface passivation equipment includes multi-functional PECVD at least, and multi-functional PECVD plates silicon oxide film, amorphous silicon layer and the normal position doping to amorphous silicon layer to the back of silicon chip, and the reaction temperature that corresponds is 400~600 ℃, multi-functional PECVD heats the silicon chip after the coating film to more than 600 ℃ from the annealing stove that takes the heating and cooling function or be located after the multi-functional PECVD process, makes amorphous silicon layer turn into the polycrystalline silicon layer, then cools down to 400~600 ℃. The utility model discloses utilize multi-functional PECVD from taking the technology that goes up and down the temperature function or multi-functional PECVD + annealing stove goes up and down the temperature to replace current LPCVD + washing technology of etching, realize the independent deposit to the silicon chip back, multi-functional PECVD can not take place the effect to the front of silicon chip when the deposit, solved among the prior art to the positive "plate earlier the back wash the drawback of plating again" of silicon chip, simplified current process step, save and wash the etching process, reduce and arouse the adverse effect to the positive coating film of silicon chip from this.

Description

TOPCon battery surface passivation equipment

Technical Field

The utility model belongs to the technical field of solar cell passivation technique and specifically relates to a TOPCon battery surface passivation equipment of oxide layer and the polycrystalline silicon thin layer of high doping that relates to ultra-thin can tunnel through.

Background

The solar photovoltaic cell is a novel cell which directly converts solar light energy into electric energy. Silicon-based silicon photovoltaic cells are commonly used today, including single crystal silicon, polycrystalline silicon, and amorphous silicon photovoltaic cells. With the improvement of the quality of silicon wafers, the surface recombination of crystalline silicon cells becomes a main factor restricting the efficiency of the crystalline silicon cells, and the surface passivation technology is particularly important. TOPCon (Tunnel Oxide Passivated Contact) has become a research hotspot as a novel passivation technology, which is to generate an ultrathin tunnelable Oxide layer and a highly doped polysilicon layer on the surface of a battery, wherein the passivation effect of the Oxide layer and the field passivation effect of the highly doped polysilicon layer can greatly reduce the minority carrier recombination rate, and the highly doped polysilicon layer has good conductivity for majority carriers, so that the TOPCon battery has high open-circuit voltage and filling factor.

The TOPCon cell technology is mainly applied to N-type crystalline silicon solar cells and is characterized in that silicon oxide (SiO) is plated on the back surface of a silicon wafer₂) Film and polysilicon layer (poly-silicon) and doping the polysilicon layer, and plating aluminum oxide (Al) on the front surface of the silicon wafer₂O₃) Film and silicon nitride (Si)_xN_y) Films, and the like. The double-sided TOPCon battery technology also needs to plate silicon nitride (Si) on the back of the silicon wafer_xN_y) Membrane, whereas the one-sided TOPCon cell technology does not. The process flow of the existing TOPCon battery technology can be summarized as follows: 1. cleaning and texturing; 2. b diffusion; 3. etching; 4. plating a silicon oxide film and a polysilicon layer on the back of the silicon wafer and carrying out doping treatment; 5. cleaning and etching; 6. and the front surface of the silicon chip is plated with an aluminum oxide film and a silicon nitride film. Wherein the content of the first and second substances,the process for coating the back surface of the silicon wafer generally adopts the following technology: 1. and (3) plating a silicon oxide film and a polysilicon layer by using LPCVD equipment, and doping the polysilicon layer. 2. And (3) plating a silicon oxide film and a polysilicon layer by using LPCVD equipment, and doping the polysilicon layer by using a diffusion doping process. 3. And (3) plating a silicon oxide film and a polysilicon layer by using LPCVD equipment, and doping the polysilicon layer by using an ion implantation process. Among the above techniques, LPCVD (low pressure Chemical Vapor Deposition) deposits the back and front of the silicon wafer simultaneously during operation, and after the back is coated, the front and side of the silicon wafer need to be cleaned and etched to remove the deposited layer on the front of the silicon wafer, so that the front of the silicon wafer is kept clean, and then the front of the silicon wafer is coated by PECVD (Plasma enhanced Chemical Vapor Deposition) or other devices. Therefore, in the prior art, the front surface of the silicon wafer is plated firstly, then washed and then plated when the LPCVD is used for plating, so that the process is complicated, time and labor are wasted, the production cost is high, and the production efficiency is low. If a deviation occurs in the cleaning etching, the yield of the silicon wafer is reduced. The conventional LPCVD equipment used in the industry to deposit the polysilicon layer is limited by the above features, which is a common technical idea in the industry.

SUMMERY OF THE UTILITY MODEL

The applicant provides TOPCon battery surface passivation equipment with a reasonable structure aiming at the defects of complex procedures, time and labor waste, high production cost, low production efficiency, high risk of unfinished products and the like of the existing TOPCon battery surface passivation technology, and the TOPCon battery surface passivation equipment can replace the existing LPCVD + cleaning and etching process by using multifunctional PECVD (multifunctional PECVD) or multifunctional PECVD + annealing furnace temperature raising and lowering process (the multifunctional PECVD equipment cancels the temperature raising and lowering function to save time) which has the temperature raising and lowering function and can deposit various films in the same cavity, so that the existing procedure steps are simplified, the cleaning and etching procedures are omitted, the adverse effect on the front surface of a silicon wafer is reduced, the production efficiency is improved, and the production cost is reduced.

The utility model discloses the technical scheme who adopts as follows:

a TOPCon battery surface passivation device at least comprises a multifunctional PECVD (plasma enhanced chemical vapor deposition), wherein the multifunctional PECVD is used for plating a silicon oxide film and an amorphous silicon layer on the back surface of a silicon wafer and for in-situ doping of the amorphous silicon layer, the corresponding reaction temperature is 400-600 ℃, the multifunctional PECVD is provided with a temperature raising and lowering function or is positioned in an annealing furnace after the multifunctional PECVD process, the silicon wafer after being plated is heated to more than 600 ℃, the amorphous silicon layer is converted into a polycrystalline silicon layer, and then the temperature is lowered to 400-600 ℃.

As a further improvement of the above technical solution:

the multifunctional PECVD has a temperature increasing and decreasing function or an annealing furnace positioned after the multifunctional PECVD procedure heats the coated silicon wafer to 600-1000 ℃.

Also comprises a device or a device combination for plating the front surface of the silicon wafer with the aluminum oxide film and the silicon nitride film.

The equipment for plating the aluminum oxide film and the silicon nitride film is ALD + PECVD, plate type two-in-one PECVD or tube type two-in-one PECVD.

In the case of using the multifunctional PECVD + annealing furnace in combination, the apparatus for plating the aluminum oxide film and the silicon nitride film is provided after the annealing furnace process or after the multifunctional PECVD process and before the annealing furnace process.

When plate type two-in-one PECVD or tubular type two-in-one PECVD is used, the corresponding reaction temperature is 400-600 ℃; when the ALD and PECVD combination is used, the corresponding temperature of the ALD is less than 300 ℃, and the corresponding reaction temperature of the PECVD is 400-600 ℃.

The utility model has the advantages as follows:

the utility model discloses utilize multi-functional PECVD from taking the technology of heating and cooling function or multi-functional PECVD + annealing stove heating and cooling to replace current LPCVD + washing technology of etching, realize the independent deposit to the silicon chip back, multi-functional PECVD can not take place the effect to the front of silicon chip when the deposit, solved among the prior art to the positive "plate earlier the back wash the drawback of plating again" of silicon chip, the utility model discloses take multi-functional PECVD cooperation heating and cooling technology, simplified current process step, save and wash the etching process, reduce the positive multitime processing to the silicon chip, reduce and arouse the adverse effect to the positive coating film of silicon chip from this. Meanwhile, compared with the process of plating first and then washing, the temperature rise and fall process is easier to realize, the production efficiency is improved, and the production cost is reduced. The utility model discloses utilize the technology of heating and cooling to turn into the polycrystalline silicon layer with amorphous silicon layer heating, make the utility model discloses a multi-functional PECVD possesses LPCVD's similar technological effect to this defect of solving LPCVD equipment existence in TOPCon battery surface passivation, develops a new style, has obvious technological innovation.

Drawings

Fig. 1 is a schematic diagram of a TOPCon cell surface passivation structure.

In the figure: 1. a silicon wafer; 2. a silicon oxide film; 3. a polysilicon layer; 4. an aluminum oxide film; 5. and a silicon nitride film.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

In this patent, the multifunctional PECVD refers to a PECVD apparatus (having all or some of the above functions according to circumstances) that can deposit a tunneling oxide layer, an amorphous silicon layer, a polysilicon layer (requiring temperature rise) and a silicon nitride layer in the same chamber and can rapidly raise and lower the temperature, and is used for depositing the back surface of a silicon wafer of a TOPCon cell in this patent. The tubular two-in-one PECVD device is tubular PECVD equipment which can deposit all or any one of aluminum oxide, silicon oxynitride and silicon nitride in the same chamber; the plate type two-in-one PECVD device is a plate type PECVD device which can be used for sequentially depositing all or any one of aluminum oxide, silicon oxynitride and silicon nitride in different chambers of the same device, and the tubular type two-in-one PECVD device or the plate type two-in-one PECVD device is used for depositing the front side of a silicon wafer of a TOPCon battery.

Referring to fig. 1, the TOPCon battery surface passivation apparatus of the present invention at least includes a multifunctional PECVD, which is used to plate a silicon oxide film 2, an amorphous silicon layer and dope the amorphous silicon layer on the back surface of a silicon wafer 1 in situ, and the reaction temperature is 400-600 ℃, preferably 450 ℃. The multifunctional PECVD has a temperature increasing and decreasing function or an annealing furnace positioned after the multifunctional PECVD procedure heats the coated silicon wafer 1 to above 600 ℃, preferably 600-1000 ℃, so that the amorphous silicon layer is converted into a polycrystalline silicon layer 3, and then the temperature is reduced to 400-600 ℃. After the temperature raising/lowering step, a device for depositing an aluminum oxide film 4 and a silicon nitride film 5 is provided, and the front surface of the silicon wafer 1 is plated with the aluminum oxide film 4 and the silicon nitride film 5. The double-sided topocon cell technology also requires silicon nitride film plating on the back side of the silicon wafer, and the equipment used may be multifunctional PECVD or other equipment, and the silicon nitride film plating on the back side of the silicon wafer may occur before or after the temperature raising and lowering process.

The equipment for depositing the aluminum oxide film 4 and the silicon nitride film 5 can be ALD + PECVD, plate type two-in-one PECVD, tube type two-in-one PECVD and the like or a combination thereof. Among them, ALD (Atomic Layer Deposition) is used for Atomic Layer Deposition of aluminum oxide, and PECVD (Plasma Enhanced Chemical Vapor Deposition) is used for Plasma Enhanced Chemical Vapor Deposition of silicon nitride, silicon oxide, silicon oxynitride, and the like. The plate type two-in-one PECVD and the tube type two-in-one PECVD can realize the front side plating of the silicon wafer 1 with the aluminum oxide film 4 and the silicon nitride film 5. When plate-type two-in-one PECVD or tube-type two-in-one PECVD is used, the corresponding reaction temperature is 400-600 ℃, and preferably 450 ℃. When the ALD and PECVD combination is used, the corresponding temperature of the ALD is less than 300 ℃, and the corresponding reaction temperature of the PECVD is 400-600 ℃, preferably 450 ℃.

As a variation, in the case where the multifunctional PECVD + annealing furnace is used in combination, the apparatus for depositing the aluminum oxide film 4 and the silicon nitride film 5 may be further provided to plate the aluminum oxide film 4 and the silicon nitride film 5 on the front surface of the silicon wafer 1 after the multifunctional PECVD process and before the annealing furnace process.

The utility model discloses an implementation method of TOPCon battery surface passivation equipment includes following step:

and 101, sequentially carrying out cleaning, texturing, boron diffusion, etching and other process treatments on the silicon wafer 1.

102, plating a silicon oxide film 2, an amorphous silicon layer and in-situ doping on the back surface of a silicon wafer 1 by using multifunctional PECVD, wherein the corresponding reaction temperature is 400-600 ℃, and preferably 450 ℃.

103, heating the coated silicon wafer 1 to a temperature higher than 600 ℃, preferably 600-1000 ℃ by using the multifunctional PECVD with a temperature raising and lowering function or an annealing furnace positioned after the multifunctional PECVD process, converting the amorphous silicon layer into a polycrystalline silicon layer 3, and then cooling to 400-600 ℃.

And 104, plating the aluminum oxide film 4 and the silicon nitride film 5 on the front surface of the silicon wafer 1. The equipment for depositing the aluminum oxide film 4 and the silicon nitride film 5 can be ALD + PECVD, plate type two-in-one PECVD, tube type two-in-one PECVD, and the like or a combination thereof.

When plate-type two-in-one PECVD or tube-type two-in-one PECVD is used, the corresponding reaction temperature is 400-600 ℃, and preferably 450 ℃. When the ALD and PECVD combination is used, the corresponding temperature of the ALD is less than 300 ℃, and the corresponding reaction temperature of the PECVD is 400-600 ℃, preferably 450 ℃.

It should be noted that, for the double-sided TOPCon cell technology, silicon nitride film plating is also required on the back side of the silicon wafer, the equipment used may be multi-functional PECVD or other equipment, and the silicon nitride film plating on the back side of the silicon wafer may occur before or after the step 103.

Step 101 is a conventional process for passivation of a topocon cell, and is not described in detail in this embodiment.

After the step 102 is finished, the silicon wafer 1 may be cleaned, so as to ensure the surface cleanness of the silicon wafer 1, ensure the production accuracy, and determine whether the cleaning process is needed.

The utility model discloses another implementation method of TOPCon battery surface passivation equipment includes following step:

step 201, the silicon wafer 1 is sequentially subjected to cleaning, texturing, boron diffusion, etching and other processes.

Step 202, plating a silicon oxide film 2, an amorphous silicon layer and in-situ doping on the back surface of the silicon wafer 1 by using multifunctional PECVD, wherein the corresponding reaction temperature is 400-600 ℃, and preferably 450 ℃.

The double-sided TOPCon battery technology also needs to plate a silicon nitride film on the back surface of a silicon wafer, while the single-sided TOPCon battery technology does not need.

Step 203, plating the front surface of the silicon wafer 1 with an aluminum oxide film 4 and a silicon nitride film 5. The equipment for depositing the aluminum oxide film 4 and the silicon nitride film 5 can be ALD + PECVD, plate type two-in-one PECVD, tube type two-in-one PECVD, and the like or a combination thereof.

And 204, heating the coated silicon wafer 1 to above 600 ℃, preferably 600 ℃ by using the multifunctional PECVD with a temperature increasing and decreasing function or an annealing furnace positioned after the multifunctional PECVD process, so that the amorphous silicon layer is converted into a polycrystalline silicon layer 3, and then cooling to 400-600 ℃.

The utility model discloses utilize multi-functional PECVD to carry out deposit alone to the 1 back of silicon chip, recycle multi-functional PECVD turns into polycrystalline silicon layer 3 with the heating of amorphous silicon layer from the annealing stove that takes the heating and cooling function or be located after the multi-functional PECVD process, realizes LPCVD's similar technological effect, and the replacement is to the positive "plating earlier the back and wash plating again" of silicon chip technology, simplifies the process flow, and it is more convenient to make production technology.

The above description is illustrative of the present invention and is not intended to limit the present invention, and the present invention may be modified in any manner without departing from the spirit of the present invention.

Claims

1. A topocon battery surface passivation apparatus characterized by: the method at least comprises a multifunctional PECVD (plasma enhanced chemical vapor deposition), wherein the back of a silicon wafer (1) is plated with a silicon oxide film (2), an amorphous silicon layer and in-situ doping of the amorphous silicon layer by the multifunctional PECVD, the corresponding reaction temperature is 400-600 ℃, the multifunctional PECVD has a temperature raising and lowering function or is positioned in an annealing furnace after the multifunctional PECVD process to heat the coated silicon wafer (1) to above 600 ℃ so as to convert the amorphous silicon layer into a polycrystalline silicon layer (3), and then the temperature is reduced to 400-600 ℃; also comprises a device or a device combination for plating the front surface of the silicon wafer (1) with the aluminum oxide film (4) and the silicon nitride film (5).

2. A topocon battery surface passivation apparatus as claimed in claim 1, wherein: the multifunctional PECVD has a temperature increasing and decreasing function or an annealing furnace positioned after the multifunctional PECVD procedure heats the coated silicon wafer (1) to 600-1000 ℃.

3. A topocon battery surface passivation apparatus as claimed in claim 1, wherein: the equipment for plating the aluminum oxide film (4) and the silicon nitride film (5) is ALD + PECVD, plate type two-in-one PECVD or tube type two-in-one PECVD.

4. A topocon battery surface passivation device according to claim 1 or 3, characterized in that: in the case of using the combination of the multifunctional PECVD and the annealing furnace, the equipment for plating the aluminum oxide film (4) and the silicon nitride film (5) is arranged after the annealing furnace process or after the multifunctional PECVD process and before the annealing furnace process.

5. A topocon battery surface passivation apparatus as claimed in claim 3, wherein: when plate type two-in-one PECVD or tubular type two-in-one PECVD is used, the corresponding reaction temperature is 400-600 ℃; when the ALD and PECVD combination is used, the corresponding temperature of the ALD is less than 300 ℃, and the corresponding reaction temperature of the PECVD is 400-600 ℃.