Texturing method of silicon wafer and preparation method of solar cell
By forming a PSG film layer on the first surface of the silicon wafer and making it fit, the existing single-sided fleece making method has solved the problem that many processes have caused high costs, and the effect of reducing costs and improving yield is achieved.
Patent Information
- Application Number
- CN202411583130.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-02-18
AI Technical Summary
The single-sided fleece making process of existing silicon wafers often lead to high processing costs.
Protect by forming a PSG film layer on the first surface of the silicon wafer for protection, and stacking the two silicon wafers to make the PSG film layer bond, avoiding the fleece on the back of the silicon wafer, simplifying the process and reducing costs.
The process of forming silicon nitride thin film is reduced, thereby reducing production costs, reducing process pollution, improving yield, and achieving single-sided velvet output.
Smart Images
Figure CN119486314A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of solar cells, and specifically provides a method for texturing a silicon wafer and a method for preparing a solar cell. Background Art
[0002] With the increasing shortage of global energy, more and more attention has been paid to the use of solar energy. The application area of solar photovoltaic components is becoming wider and wider, involving multiple industries and fields.
[0003] Silicon wafers are the carriers used to produce solar cells. In the existing solar cell manufacturing process, it is necessary to texturize the surface of the silicon wafer, which mainly includes double-sided texturizing method and single-sided texturizing method. The double-sided texturizing method is to texturize both the front and back sides of the silicon wafer, while the single-sided texturizing method only requires texturizing on the front side of the silicon wafer.
[0004] In the single-sided texturing method, in order to prevent the back of the silicon wafer from forming texturing, a layer of silicon nitride film needs to be deposited on the back of the silicon wafer before texturing to protect the back of the silicon wafer. This involves many steps and results in high costs.
[0005] Therefore, this field needs a new technical solution to solve the above problems. Summary of the invention
[0006] The present invention aims to solve the above technical problem, that is, to solve the problem that the existing single-side texturing method of silicon wafers has many steps leading to high processing costs.
[0007] In a first aspect, the present invention provides a texturing method for a silicon wafer, the texturing method comprising the following steps: forming a PSG film layer on the first surfaces of two silicon wafers respectively;
[0008] Laminating the PSG film layers of the two silicon wafers;
[0009] The second surfaces of the two silicon wafers opposite to the first surfaces are textured.
[0010] In the preferred technical solution of the above texturing method, before forming the PSG film layers on the first surfaces of the two silicon wafers respectively, the texturing method further comprises:
[0011] The second surfaces of the two silicon wafers opposite to the first surfaces are bonded together.
[0012] In the preferred technical solution of the above-mentioned texturing method, laminating the PSG film layers of the two silicon wafers specifically includes:
[0013] The two silicon wafers are stacked up and down.
[0014] In the preferred technical solution of the above-mentioned texturing method, the additives used in the texturing include an active agent with a long carbon chain.
[0015] In a preferred technical solution of the above texturing method, before texturing the second surfaces of the two silicon wafers opposite to the first surfaces, the texturing method further comprises:
[0016] Acid washing the two bonded silicon wafers to remove exposed PSG; and / or
[0017] The impurities on the two bonded silicon wafers are cleaned with an alkaline solution.
[0018] In a preferred technical solution of the above texturing method, after texturing the second surfaces of the two silicon wafers opposite to the first surfaces, the texturing method further comprises:
[0019] Cleaning the two silicon wafers with an alkaline solution to remove impurities on the two silicon wafers; and / or
[0020] Separating the two bonded silicon wafers;
[0021] A first pickling operation is performed on the silicon wafer to remove the PSG film layer on the silicon wafer.
[0022] In the preferred technical solution of the above-mentioned texturing method, after the first pickling operation is performed on the silicon wafer, the texturing method further comprises:
[0023] Performing a second pickling operation on the silicon wafer to remove metal impurities on the silicon wafer; wherein the concentration of the acidic solution used in the second pickling operation is greater than the concentration of the acidic solution used in the first pickling operation; and / or
[0024] The silicon wafer is dehydrated and dried.
[0025] In the preferred technical solution of the above texturing method, before forming the PSG film layers on the first surfaces of the two silicon wafers respectively, the texturing method further comprises:
[0026] Clean the silicon wafer.
[0027] In the preferred technical solution of the above-mentioned texturing method, the cleaning of the silicon wafer specifically includes:
[0028] S110: cleaning the silicon wafer with a first alkaline solution;
[0029] S120: cleaning the silicon wafer with a second alkaline solution;
[0030] S130: cleaning alkaline residues on the silicon wafer;
[0031] Wherein, the concentration of the first alkaline solution is greater than the concentration of the second alkaline solution.
[0032] In a second aspect, the present invention further provides a method for preparing a solar cell, comprising texturing a silicon wafer using the above-mentioned texturing method.
[0033] When adopting the above technical scheme, the texturing method of the present invention forms a PSG film layer on the first surface of the silicon wafer for protection. Compared with the prior art in which a silicon nitride film is formed on the back side of the silicon wafer for protection, the present invention uses a PSG film layer instead. The existing impurity gettering process can be used to deposit a layer of PSG on the first surface of the silicon wafer as a natural mask, thereby reducing the process of forming a silicon nitride film, thereby reducing costs, and can also reduce process pollution, thereby improving yield. In addition, when texturing, two silicon wafers are stacked first so that the PSG film layers on the two silicon wafers fit together. Such an arrangement is more conducive to avoiding the formation of texturing on the first surface of the silicon wafer.
[0034] Furthermore, the present invention stacks two silicon wafers up and down, that is, places one silicon wafer on top of the other silicon wafer, and presses the other silicon wafer through the gravity of the silicon wafer itself, so that the two silicon wafers fit more closely, which is more conducive to preventing lint from forming on the back of the silicon wafer.
[0035] Furthermore, the present invention firstly performs pickling on the two silicon wafers with an acid solution before making the texture, so as to remove the PSG exposed on the two silicon wafers, which is beneficial to improve the uniformity of the texture.
[0036] Furthermore, the present invention adopts an active agent with a long carbon chain. The active agent with a long carbon chain is characterized by being hydrophilic at one end and hydrophobic at the other end. It can reduce the probability of the first surface of the silicon wafer reacting with the alkaline solution, thereby further reducing the probability of lint forming on the back of the silicon wafer.
[0037] Furthermore, the present invention helps prevent the formation of PSG on the second surface of the silicon wafer by laminating the second surfaces of the two silicon wafers, thereby facilitating the formation of a PSG film layer only on the first surface of the silicon wafer.
[0038] Furthermore, compared with the prior art in which the silicon wafer is only alkaline cleaned once, the present invention first cleans the silicon wafer with a high-concentration alkaline solution and then cleans the silicon wafer a second time with a low-concentration alkaline solution, which can more effectively remove impurities and damage on the silicon wafer and achieve a better cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:
[0040] Figure 1It is a schematic diagram of the structure of two stacked silicon wafers;
[0041] Figure 2 It is a flow chart of the texturing method of the silicon wafer of the present invention;
[0042] Figure 3 It is a flow chart of an embodiment of the method for texturing a silicon wafer of the present invention.
[0043] List of reference numerals:
[0044] 1. Silicon wafer; 2. PSG film layer; DETAILED DESCRIPTION
[0045] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.
[0046] It should be noted that in the description of the present invention, the terms "left", "right" and other terms indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0047] Specifically, the present invention provides a method for texturing a silicon wafer, such as Figure 2 As shown, the texturing method of the silicon wafer of the present invention comprises the following steps:
[0048] S100: cleaning the silicon wafer.
[0049] The first step is to clean the silicon wafer. The main purpose is to repair the mechanical damage of the silicon wafer (generally the damage caused during cutting) and remove impurities on the silicon wafer (such as oil stains and metal particles).
[0050] In step S100, illustratively, the silicon wafer is preferably placed in an alkaline solution first to remove impurities and damage on the silicon wafer, and then the alkaline residue on the silicon wafer is cleaned. That is, the silicon wafer is first damaged and the impurities are removed by an alkaline solution, and then the alkaline residue on the silicon wafer is cleaned by clean water to prevent the alkaline residue from contaminating subsequent processes.
[0051] Preferably, if Figure 3 As shown, step S100 specifically includes S110 to S130.
[0052] S110: cleaning the silicon wafer with a first alkaline solution;
[0053] S120: cleaning the silicon wafer with a second alkaline solution;
[0054] S130: cleaning alkaline residues on the silicon wafer;
[0055] Wherein, the concentration of the first alkaline solution is greater than the concentration of the second alkaline solution.
[0056] Exemplarily, the silicon wafer is first placed in a first alkaline solution for rough polishing (S110). Since the concentration of the first alkaline solution is relatively high, the silicon wafer is corroded by the first alkaline solution, preferably reducing the thickness of the silicon wafer by about 3 to 5 microns to repair mechanical damage on the silicon wafer and also remove some impurities; then the silicon wafer is placed in a second alkaline solution (S120). Since the concentration of the second alkaline solution is relatively low, the alkaline solution no longer corrodes the silicon wafer, and is mainly used to remove impurities remaining on the surface of the silicon wafer; finally, the silicon wafer is placed in clean water (S130), and the alkaline residues on the silicon wafer are removed by the clean water.
[0057] Compared with the prior art of only performing alkaline cleaning on the silicon wafer once, the present invention first cleans the silicon wafer with a high-concentration alkaline solution and then cleans the silicon wafer a second time with a low-concentration alkaline solution, which can more effectively remove impurities and damage on the silicon wafer and has a better cleaning effect.
[0058] It should be noted that the present invention does not limit the specific values of the concentration of the first alkaline solution and the concentration of the second alkaline solution. In practical applications, those skilled in the art can flexibly set the specific values of the concentration of the first alkaline solution and the concentration of the second alkaline solution based on experiments or experience.
[0059] In a preferred example, three separate holding tanks are provided on the same device, which are respectively denoted as a first holding tank, a second holding tank and a third holding tank, wherein the alkaline solution contained in the first holding tank (i.e., the first alkaline solution) is a potassium hydroxide solution (KOH), and the concentration of the alkaline solution is 1.0% to 1.5%, the alkaline solution contained in the second holding tank (i.e., the second alkaline solution) is a mixed solution of potassium hydroxide and hydrogen peroxide (KOH+H2O2), the concentration of the alkaline solution is 0.2% to 0.3%, and the concentration of the hydrogen peroxide is 2.5% to 3.5%, and the third holding tank is filled with clean water. In step S100, the silicon wafers are sequentially placed in the first holding tank, the second holding tank and the third holding tank for cleaning.
[0060] It should be noted that the alkaline solution (the first alkaline solution and the second alkaline solution) used in this step is not limited to the potassium hydroxide solution introduced above. For example, sodium hydroxide solution (NaOH) and the like may also be used. In addition, hydrogen peroxide may not be added to the second alkaline solution. Of course, it is preferred to add hydrogen peroxide to the second alkaline solution to oxidize the silicon wafer with hydrogen peroxide, so as to facilitate the removal of impurities on the silicon wafer with the alkaline solution.
[0061] In addition, it should be noted that the present invention does not limit the time for cleaning the silicon wafer in each step (S110 to S130). In practical applications, those skilled in the art can flexibly set the specific value of the cleaning time of each step based on experiments or experience. The present invention preferably sets the cleaning time to 1 minute to 5 minutes.
[0062] S200: Laminating the second surfaces of the two silicon wafers.
[0063] Specifically, the two silicon wafers are stacked so that the second surfaces of the two silicon wafers are in contact with each other.
[0064] S300: forming PSG (phosphosilicate glass) film layers on first surfaces of two silicon wafers respectively.
[0065] The second surface is a surface opposite to the first surface.
[0066] After the silicon wafer is cleaned, a PSG film layer needs to be provided on the first surface of the silicon wafer (eg, the back side of the silicon wafer) to protect the back side of the silicon wafer and prevent lint from forming on the back side during texturing.
[0067] By using the PSG film layer, there is no need to add a new process. The existing gettering process can be used to deposit a layer of PSG on the first surface of the silicon wafer (e.g., the back of the silicon wafer) as a natural mask to protect the back of the silicon wafer and prevent lint from forming on the back of the silicon wafer. For example, phosphorus oxychloride can be used to diffuse and getter to form the PSG film layer, and the thickness of the PSG film layer is preferably 20 nanometers to 30 nanometers.
[0068] Compared with the prior art of forming a silicon nitride film on the back of the silicon wafer for protection, the present invention uses a PSG film layer instead, which reduces the steps of forming the silicon nitride film, thereby reducing production costs. In addition, it can also reduce process pollution, thereby improving yield.
[0069] Furthermore, in a specific operation process, two silicon wafers are first stacked, and the second surfaces of the two silicon wafers (eg, the front surfaces of the silicon wafers) are bonded together, and then a PSG film layer is formed on the first surfaces of the two silicon wafers (eg, the back surfaces of the silicon wafers).
[0070] In other words, the two silicon wafers processed in step S100 are first stacked together so that the front sides of the two silicon wafers are in contact with each other and placed in a carrier. For example, the two stacked silicon wafers are inserted into a quartz boat carrier, and then a PSG film layer is formed on the back sides of the two silicon wafers.
[0071] It should be noted that step S200 is not necessary. In practical applications, those skilled in the art may choose to remove S200, that is, directly proceed to S300 after completing S100. Of course, it is preferred to retain step S200. Before forming PSG on the back of the silicon wafer, by laminating the front sides of the two silicon wafers, it is beneficial to prevent the formation of PSG on the front side of the silicon wafer, thereby facilitating the formation of a PSG film layer only on the back side of the silicon wafer.
[0072] S400: Laminating the PSG film layers of two silicon wafers.
[0073] Specifically, two silicon wafers are stacked to make the PSG film layers of the two silicon wafers adhere to each other.
[0074] That is to say, when making velvet, Figure 1 As shown, the PSG film layers 2 on the first surfaces (eg, back surfaces) of the two silicon wafers 1 are bonded to each other, which is more conducive to preventing lint from forming on the back surfaces of the silicon wafers, so that lint only forms on the front surfaces of the silicon wafers.
[0075] More preferably, if Figure 1 As shown, two silicon wafers 1 are stacked one on top of the other.
[0076] That is, one of the silicon wafers 1 is placed on top of the other silicon wafer 1, and the silicon wafers are pressed on the other silicon wafer by their own gravity, so that the two silicon wafers fit more closely, which is more conducive to preventing lint from forming on the back of the silicon wafers.
[0077] S800: texturing the second surfaces of the two silicon wafers.
[0078] For example, two silicon wafers stacked horizontally are inserted into a special flower basket, the two silicon wafers are pressed tightly by a pressure rod, and then put into a slot machine for texturing. The slot body of the slot machine is filled with chemicals, which mainly include methyl hydroxide (KOH), deionized water and additives.
[0079] Further preferably, in step S300, the additive used in texturing includes an active agent with a long carbon chain.
[0080] Surfactants with long carbon chains (such as dodecyl ethoxy sulfobetaine, dodecyl dimethyl hydroxypropyl sulfobetaine, etc.) are characterized by being hydrophilic at one end and hydrophobic at the other end, which can reduce the probability of the back of the silicon wafer reacting with the alkaline solution, thereby further reducing the probability of lint on the back of the silicon wafer.
[0081] That is to say, the silicon wafer of the present invention has triple protection of PSG, additives and self-gravity bonding. Under the effect of the triple protection, the probability of lint on the back of the silicon wafer can be greatly reduced, thereby achieving single-sided lint removal.
[0082] Preferably, if Figure 2 and Figure 3 As shown, in step S800, before texturing the second surfaces of the two silicon wafers, the texturing method of the present invention further includes the following steps:
[0083] S500: The two bonded silicon wafers are pickled to remove the exposed PSG.
[0084] That is to say, after the PSG film layers on the two silicon wafers are bonded together, the silicon wafers are not placed in a texturing agent for texturing first, but are first pickled with an acid solution to remove the exposed PSG on the two silicon wafers. Etching away the exposed PSG is conducive to improving the uniformity of the texturing. The exposed PSG refers to the PSG other than the PSG on the back of the two silicon wafers.
[0085] Illustratively, in step S500, a hydrofluoric acid solution (HF) with a concentration of 1.0% to 1.5% is used. The acid concentration is relatively low and can only corrode the exposed PSG. Two stacked silicon wafers are placed in the acid solution, and the reaction time is preferably controlled to be 80 seconds to 150 seconds.
[0086] It should be noted that the acidic solution in this step is not limited to the above-mentioned hydrofluoric acid solution. Those skilled in the art may also use other types of acidic solutions, such as hydrochloric acid solution (HCl), etc., as needed in practical applications.
[0087] In addition, it should be noted that after the silicon wafer is pickled, it is preferred to first wash away the residual acid on the silicon wafer with clean water before proceeding to the next step.
[0088] More preferably, if Figure 2 and Figure 3 As shown, in step S800, before texturing the second surfaces of the two silicon wafers, the texturing method of the present invention further includes the following steps:
[0089] S600, cleaning the silicon wafer with an alkaline solution to remove impurities on the silicon wafer.
[0090] That is to say, after the PSG film layers on the two silicon wafers are bonded together, the silicon wafers are not placed in the texturing agent first, but the impurities (such as organic matter and particles, etc.) on the silicon wafers are first removed by an alkaline solution.
[0091] Illustratively, in step S600, a mixed solution of potassium hydroxide and hydrogen peroxide (KOH+H2O2) is used, wherein the ratio of the solution H2O:H2O2:KOH is preferably 7:2:1, and two stacked silicon wafers are placed in the alkaline solution, and the reaction time is preferably controlled within a range of 100 to 150 seconds.
[0092] It should be noted that the alkaline solution used in this step is not limited to the potassium hydroxide solution introduced above. For example, sodium hydroxide solution (NaOH) and the like may also be used. In addition, hydrogen peroxide may not be added to the alkaline solution. Of course, it is preferred to add hydrogen peroxide to the alkaline solution to oxidize the silicon wafer with hydrogen peroxide, so as to facilitate the removal of impurities on the silicon wafer with the alkaline solution.
[0093] It should be noted that, in the case of including step S500, step S500 may be performed first and then step S600, or step S600 may be performed first and then step S500.
[0094] Further preferably, in step S600, after removing impurities on the silicon wafer by using an alkaline solution, the texturing method of the present invention further comprises:
[0095] S700, cleans away alkaline residues on silicon wafers.
[0096] In a preferred example, five separate holding tanks are provided on the same device, which are respectively denoted as the first holding tank, the second holding tank, the third holding tank, the fourth holding tank and the fifth holding tank, wherein the first holding tank is filled with an acidic solution, the second holding tank and the fourth holding tank are filled with clean water, the third holding tank is filled with an alkaline solution, and the fifth holding tank is filled with a texturing agent. After step S400, two horizontally stacked silicon wafers are placed in the first holding tank, the second holding tank, the third holding tank, the fourth holding tank and the fifth holding tank in turn.
[0097] Preferably, if Figure 2 and Figure 3 As shown, after step S800, the texturing method of the present invention further includes:
[0098] S900: After the texturing is completed, the silicon wafer is cleaned.
[0099] The purpose of cleaning the silicon wafer after texturing is mainly to remove impurities and PSG film on the silicon wafer to prepare for subsequent steps.
[0100] Preferably, if Figure 3 As shown, step S900 specifically includes S910 to S950.
[0101] S910: Cleaning the silicon wafer with an alkaline solution to remove impurities on the silicon wafer.
[0102] After the texturing is completed, the silicon wafer is cleaned again with an alkaline solution to remove impurities on the silicon wafer, such as organic matter, foreign particles, oil stains and additive residues.
[0103] Exemplarily, the silicon wafer can be placed in an alkaline solution, which is a mixed solution of potassium hydroxide and hydrogen peroxide (KOH+H2O2), wherein the ratio of the solution H2O:H2O2:KOH is preferably 5:1:1, and the reaction time is preferably controlled within a range of 100 seconds to 150 seconds.
[0104] It should be noted that the alkaline solution used in this step is not limited to the potassium hydroxide solution introduced above. For example, sodium hydroxide solution (NaOH) and the like may also be used. In addition, hydrogen peroxide may not be added to the alkaline solution. Of course, it is preferred to add hydrogen peroxide to oxidize the silicon wafer with hydrogen peroxide, so as to facilitate the removal of impurities on the silicon wafer with an alkaline solution.
[0105] In addition, it should be noted that after the impurities on the silicon wafer are removed by using an alkaline solution, the residual alkali on the silicon wafer is preferably washed off by using clean water.
[0106] S920: Separate the two bonded silicon wafers.
[0107] S930: performing a first pickling operation on the silicon wafer to remove the PSG film layer on the silicon wafer;
[0108] After the impurities on the silicon wafer are removed by an alkaline solution, the PSG film on the silicon wafer is removed by an acidic solution.
[0109] Among them, before the silicon wafer is pickled, the two stacked silicon wafers are separated first, which makes it easier to remove the PSG film layer on the silicon wafer.
[0110] It should be noted that step S910 is not necessary, and those skilled in the art may cancel step S910 in actual application. Of course, it is preferred to retain step S910.
[0111] In addition, it should be noted that, in the case of retaining S910, S920 can be performed before the above-mentioned step S910, that is, separating the two stacked silicon wafers, or the two stacked silicon wafers can be separated after step S910, for example, after the alkaline residues on the two silicon wafers are washed off with clean water, the two stacked silicon wafers are separated and then respectively inserted into single-wafer flower baskets.
[0112] In addition, it should be noted that before performing step S930, it is preferred to dehydrate (for example, slowly pull) and dry the silicon wafers first, and before this step, the two stacked silicon wafers are separated and inserted into single-wafer baskets respectively, and then the silicon wafers are dehydrated and dried, which has a better effect.
[0113] S940: performing a second pickling operation on the silicon wafer to remove metal impurities on the silicon wafer.
[0114] The concentration of the acid solution used in the first pickling operation is less than the concentration of the acid solution used in the second pickling operation.
[0115] That is to say, when the silicon wafer is pickled, the separated silicon wafer is first placed in a first acidic solution with a lower concentration, and the PSG film layer on the back of the silicon wafer is removed by the first acidic solution. Then the silicon wafer is placed in a second acidic solution with a higher concentration, and the metal impurities on the silicon wafer are removed by the second acidic solution.
[0116] Exemplarily, the first acidic solution uses a hydrofluoric acid solution (HF) with a concentration of 0.1Wt% to 0.3Wt%, and the acid concentration is relatively low, which can only etch away the PSG on the silicon wafer, and the reaction time is preferably controlled at 100 seconds to 150 seconds. The second acidic solution uses a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl), and the reaction time is preferably controlled at 60 seconds to 100 seconds, wherein the concentration of HF is 5.0Wt% to 10Wt%, and the concentration of HCl is 0.02Wt% to 0.05Wt%.
[0117] It should be noted that the first acidic solution in this step is not limited to the above-mentioned hydrofluoric acid solution. In practical applications, those skilled in the art may also use other types of acidic solutions, such as hydrochloric acid solution (HCl), etc. as needed. Similarly, the second acidic solution in this step is not limited to a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl), for example, only hydrofluoric acid solution may be used.
[0118] In addition, it should be noted that after step S930 and before step S940, it is preferred to first wash away the residual acid on the silicon wafer with clean water.
[0119] In addition, it should be noted that the above step S940 is not necessary, and those skilled in the art can cancel this step as needed in actual applications. Of course, it is preferred to retain this step to improve the yield.
[0120] S950: Dehydrate and dry the silicon wafer.
[0121] That is, after the silicon wafer is pickled with an acid solution, the silicon wafer is dehydrated and dried again.
[0122] In a second aspect, the present invention further provides a method for preparing a solar cell, the method comprising texturing a silicon wafer using the above-mentioned texturing method.
[0123] That is to say, in the process of preparing solar cells, it is preferred to use the above-mentioned texturing method to texturize the silicon wafer, and then complete the subsequent PECVD (plasma enhanced chemical vapor deposition) to prepare amorphous silicon, doped microcrystalline silicon and other functional layers, PVD (physical vapor deposition) to prepare TCO (transparent conductive oxide) and screen printing to prepare electrodes and other processes.
[0124] It should be noted that the texturing method of the present invention is preferably applicable to the preparation of HJT solar cells (heterojunction solar cells).
[0125] Those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims of the present application, any one of the claimed embodiments may be used in any combination.
[0126] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.
Claims
1. A method for texturing a silicon wafer, characterized in that: The texturing method comprises the following steps: forming a PSG film layer on the first surfaces of the two silicon wafers respectively; Laminating the PSG film layers of the two silicon wafers; The second surfaces of the two silicon wafers opposite to the first surfaces are textured.
2. The texturing method according to claim 1, characterized in that: Before forming the PSG film layers on the first surfaces of the two silicon wafers respectively, the texturing method further comprises: The second surfaces of the two silicon wafers opposite to the first surfaces are bonded together.
3. The texturing method according to claim 1, characterized in that: The step of laminating the PSG film layers of the two silicon wafers specifically includes: The two silicon wafers are stacked up and down.
4. The texturing method according to claim 1, characterized in that: The additives used in the texturing process include an active agent with a long carbon chain.
5. The texturing method according to claim 1, characterized in that: Before texturing the second surfaces of the two silicon wafers opposite to the first surfaces, the texturing method further comprises: Acid washing the two bonded silicon wafers to remove exposed PSG; and / or The impurities on the two bonded silicon wafers are cleaned with an alkaline solution.
6. The texturing method according to claim 1, characterized in that: After texturing the second surfaces of the two silicon wafers opposite to the first surfaces, the texturing method further comprises: Cleaning the two silicon wafers with an alkaline solution to remove impurities on the two silicon wafers; and / or Separating the two bonded silicon wafers; A first pickling operation is performed on the silicon wafer to remove the PSG film layer on the silicon wafer.
7. The texturing method according to claim 1, characterized in that: After the silicon wafer is subjected to the first pickling operation, the texturing method further comprises: Performing a second pickling operation on the silicon wafer to remove metal impurities on the silicon wafer; wherein the concentration of the acidic solution used in the second pickling operation is greater than the concentration of the acidic solution used in the first pickling operation; and / or The silicon wafer is dehydrated and dried.
8. The texturing method according to any one of claims 1 to 7, characterized in that: Before forming the PSG film layers on the first surfaces of the two silicon wafers respectively, the texturing method further comprises: Clean the silicon wafer.
9. The texturing method according to claim 8, characterized in that: The cleaning of the silicon wafer specifically includes: S110: cleaning the silicon wafer with a first alkaline solution; S120: cleaning the silicon wafer with a second alkaline solution; S130: cleaning alkaline residues on the silicon wafer; Wherein, the concentration of the first alkaline solution is greater than the concentration of the second alkaline solution.
10. A method for preparing a solar cell, characterized in that: include: The silicon wafer is textured using the texture making method described in any one of claims 1 to 9.