Method for testing parameters of single-layer film in laminated film battery piece and application of method

Abstract

The invention belongs to the field of crystalline silicon solar cells, and relates to a method for testing parameters of a single-layer film in a laminated film cell and a process debugging method applied to the laminated film cell, the parameters of the single-layer film comprise the refractive index of the single-layer film, and the testing method comprises the following steps: providing a silicon substrate for testing the cell; the method comprises the following steps of: depositing a sample film of a single-layer film on at least one side surface of a silicon substrate of a tested battery piece by adopting a deposition process of the single-layer film when the laminated film battery piece is prepared; and testing the refractive index of the sample film, and obtaining the refractive index of the single-layer film in the laminated film battery piece based on the refractive index of the sample film. By testing and calculating the thickness of the single-layer film in the laminated film, a basis is provided for process matching optimization and debugging of the single-layer film in the laminated film on different production lines, the light absorptivity of the battery is improved, and the conversion efficiency of the battery is improved.

Description

Technical Field

[0001] The present application relates to the technical field of crystalline silicon solar cells, and particularly to a method for testing single-layer film parameters in a stacked film solar cell and its application. Background Art

[0002] At present, the PECVD technology (Plasma Enhanced Chemical Vapor Deposition) is used to prepare an antireflection passivation film in the production process of crystalline silicon cells. In order to balance the relationship between antireflection and passivation, a stacked film deposition method such as a silicon nitride film, a silicon oxynitride film, or a silicon oxide film is generally adopted.

[0003] The front surface of the crystalline silicon cell substrate generally adopts a textured light-trapping structure to increase the optical path of short-wavelength light in the silicon wafer body; while the back surface generally adopts a polished structure, so that long-wavelength light is reflected back into the cell body and reused. Through the two surface optical design structures, the light absorption rate is increased, thereby increasing the photocurrent and improving the cell conversion efficiency. In the process of cell process regulation, an ellipsometer is generally used to measure the thickness and refractive index of the above two different surface structure film layers.

[0004] However, the film thickness and refractive index of the bottom single-layer film close to the silicon wafer sub-layer in the stacked film have a great influence on the potential-induced degradation at the component end. At present, there is no good method in industrial applications to characterize the film thickness and refractive index of a single film layer in the stacked film, and only the film thickness and refractive index of the entire stacked film can be monitored. Therefore, it is also impossible to optimize the process for a single film layer and adjust the film thickness and refractive index. Summary of the Invention

[0005] Based on this, the present application provides a method for testing single-layer film parameters in a stacked film solar cell and its application. By measuring and calculating the film thickness and refractive index of a single film layer in the stacked film solar cell, it provides a basis for the matching optimization and debugging of the single-layer film in the stacked film on different production lines, and specifically adjusts the stacked film thickness and refractive index to achieve better film layer matching and optical path management, improve the light absorption rate, increase the cell conversion efficiency, and improve the component reliability.

[0006] On the one hand, a method for testing single-layer film parameters in a stacked film solar cell is provided, which is applied to the process debugging method of the stacked film solar cell. The single-layer film parameters include the refractive index of the single-layer film, and the testing method includes the following steps:

[0007] Provide a test cell silicon substrate;

[0008] Adopt the deposition process of the single-layer film when preparing the laminated film battery cell, and deposit a sample film of the single-layer film on at least one side of the silicon substrate of the test battery cell. Among them, the deposition time in the deposition process of the sample film adopts the calculated theoretical deposition time T, and the calculation steps of the theoretical deposition time T include:

[0009] Preset a first thickness D, where the first thickness D is the preset thickness of the sample film of the single-layer film deposited on the silicon substrate of the test battery cell;

[0010] Based on the first thickness D, calculate the theoretical deposition time T, where the theoretical deposition time T is the time required to deposit the sample film with a thickness of the first thickness D on the silicon substrate of the test battery cell;

[0011] Test the refractive index of the sample film, and obtain the refractive index of the single-layer film in the laminated film battery cell based on the refractive index of the sample film.

[0012] In one embodiment, the single-layer film parameters further include the thickness of the single-layer film. After depositing the sample film of the single-layer film on at least one side of the silicon substrate of the test battery cell, the following steps are further included:

[0013] Test the test thickness A of the sample film;

[0014] Calculate the deposition rate f based on the test thickness A;

[0015] Calculate the thickness dn of the single-layer film based on the deposition rate f.

[0016] In one embodiment, the front or back of the silicon substrate of the test battery cell is a polished surface or a textured surface, and the sample film is deposited on the polished surface or the textured surface of the silicon substrate of the test battery cell.

[0017] In one embodiment, the calculating the theoretical deposition time T based on the first thickness D includes:

[0018] Calculate the theoretical deposition time T required for the single-layer film sample according to the formula T = D / F, where F is the empirical deposition rate in the deposition process of the single-layer film when preparing the laminated film battery cell.

[0019] In one embodiment, the deposition rate F on the polished surface of the silicon substrate of the test battery cell is 0.1 - 0.2 nm / s, and the deposition rate F on the textured surface of the silicon substrate of the test battery cell is 0.05 - 0.1 nm / s.

[0020] In one embodiment, calculating the deposition rate f based on the test thickness A includes:

[0021] Calculate the deposition rate f according to the formula f = A / T;

[0022] Calculating the thickness dn of the single-layer film based on the deposition rate f includes:

[0023] Obtain the thickness of the single-layer film according to the formula dn = f × tn, where f is the deposition rate calculated based on the test thickness A and the theoretical time T of the single-layer sample film, and tn is the deposition time for depositing the single-layer film when fabricating the stacked film solar cell.

[0024] In one embodiment, the thickness of the stacked film solar cell is 60 - 90 nm, and the single-layer film is a silicon nitride film, a silicon oxide film, or a silicon oxynitride film; the thickness of the single-layer film is less than 60 nm, and the first thickness D is 74 ± 15 nm.

[0025] On the other hand, provided is an application of the above test method in testing the thickness and / or refractive index of a single-layer film in a stacked film solar cell.

[0026] On the other hand, provided is a process debugging method for a stacked film solar cell, and the process debugging method is a method for debugging the process of the second production line by applying the process of the first production line, including the following steps:

[0027] S1. Test and obtain the first refractive index and / or the first thickness of at least one single-layer film in the stacked film solar cell fabricated on the first production line, where the first refractive index and / or the first thickness are measured by the test method described in any one of the above, and at least one single-layer film in the stacked film solar cell is fabricated by a first deposition process;

[0028] S2. Test and obtain the second refractive index and / or the second thickness of the at least one single-layer film in the stacked film solar cell fabricated on the second production line during the expansion of the production line, where the second refractive index and / or the second thickness are measured by the test method described in any one of the above, and at least one single-layer film in the stacked film solar cell is fabricated by the first deposition process;

[0029] S3. Compare the first refractive index with the second refractive index, and / or compare the first thickness with the second thickness, and adjust the deposition process of the second production line after expansion based on the difference between the first refractive index and the second refractive index and / or the difference between the first thickness and the second thickness.

[0030] In one embodiment, the stacked film solar cell includes a cell silicon substrate, a back stacked film, and a front stacked film. The back stacked film includes 3 sequentially deposited silicon nitride layers; the front stacked film includes 3 sequentially deposited silicon nitride layers and 2 silicon oxynitride layers.

[0031] The present invention has at least one of the following beneficial effects:

[0032] In the present invention, a single-layer sample film is deposited on the back or front of the silicon substrate of the test cell to replace the single-layer film in the stacked film for direct full-spectrum ellipsometry testing. Generally, the film thickness range of the full-spectrum ellipsometry testing matches the thickness of the stacked film. If the film thickness is too small or too large, there may be testing errors. Therefore, to reduce the testing errors, the preset thickness D of the sample film in this method is designed to be approximately equal to the thickness of the stacked film. Based on the preset thickness D of the single-layer sample film, the theoretical deposition time T is calculated. The single-layer sample film is deposited according to the theoretical deposition time T and the theoretical deposition rate F of the single-layer film in the stacked film. Based on the refractive index of this single-layer film, the refractive index of the single-layer film in the stacked-film cell can be characterized. The refractive index of the single-layer film in the stacked-film cell obtained by this method can be used to characterize the refractive index of the single-layer film in the stacked films prepared by different production line processes. The difference between the refractive indices of the two single-layer films obtained by this method can characterize the difference in the refractive indices of the single-layer films in the stacked films prepared by different production line processes. During large-scale production, the refractive index of the single-layer film in the stacked film of the new production line is adjusted according to the difference in the refractive indices of the sample films corresponding to the single-layer films in the stacked films of the two production lines measured by this method to reduce the difference, so that the cells produced by the new production line during large-scale production also meet the standards of the cells. Therefore, the present invention provides a basis for the matching optimization and debugging of the single-layer films in the stacked films on different production lines, targets the adjustment of the bottom refractive index, realizes better film layer matching and optical path management, improves the light absorption rate of the cell, and increases the cell conversion efficiency. Description of the Drawings

[0033] Figure 1 It is a process flow chart of the method for testing the refractive index of the single-layer film in the stacked-film cell in Embodiment 1 of the present invention. Detailed Embodiments

[0034] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape and size of the components during actual implementation. The types, quantities and proportions of the components during actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0036] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.

[0037] The directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "middle", "longitudinal", "lateral", "horizontal", "inner", "outer", "radial", "circumferential" and the like in this specification are based on the directions or positional relationships shown in the drawings and are only for the convenience of simplifying the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0038] The laminated film cell of the present invention refers to a cell obtained by sequentially depositing at least two single film layers on at least one side of a cell silicon substrate, that is, a cell with a laminated film;

[0039] The single-layer film in the present invention refers to: a single-layer film layer in the laminated film of the laminated film solar cell;

[0040] The refractive index of the single-layer film in the present invention refers to: the refractive index of a single-layer film layer of the laminated film solar cell;

[0041] The sample film of the present invention refers to: a single-layer film deposited on a test piece by the same deposition process as a single-layer film in a laminated film, so as to directly perform full-spectrum ellipsometer testing of refractive index and thickness;

[0042] The first thickness D of the present invention means: in order to simulate the test conditions of preparing multilayer film solar cells on the first production line and the second production line as much as possible and reduce the error of the ellipsometer test thickness, the thickness of the sample mold should be as close as possible to the thickness of the laminated film. At the same time, in order to balance the absorption, surface passivation, and body passivation of the anti-reflection film, the deposition thickness of the sample film is designed to be 74±15nm (i.e., the first thickness D). The first thickness D is different from the thickness of the single-layer film in the laminated film corresponding to the sample mold;

[0043] The theoretical deposition time T of the present invention refers to the theoretically required time calculated by the formula T=D / F when the empirical deposition rate F of a single layer film in a stacked film is used to deposit a sample film with a thickness of D=74±15nm;

[0044] The measured thickness A of the sample film described in the present invention refers to: the measured thickness obtained by ellipsometer measurement of the sample film deposited according to the empirical deposition rate F of the single-layer film in the laminated film for a deposition time of the theoretical deposition time T.

[0045] The empirical deposition rate F of the single-layer film described in the present invention refers to: under the deposition process of the first production line, the reasonable industrial empirical deposition rate for depositing a film layer with a first thickness D estimated according to experience, so as to calculate the time T (i.e., the theoretical deposition time T) required for depositing a film layer with a first thickness D, and then the sample film can be deposited according to the calculated theoretical deposition time T.

[0046] The deposition rate f described in the present invention refers to: the deposition rate calculated by using the measured thickness A of the sample film and the theoretical time T, and the calculation formula is f = A / T, which is used to calculate the actual thickness of the single-layer film in the laminated film together with the deposition time of the single-layer film in the laminated film produced by the first production line or the second production line.

[0047] Currently, after obtaining a solar cell that meets the requirements of the cell conversion efficiency through process optimization, production needs to be carried out on multiple production lines. However, there may be significant differences in the performance of the solar cells produced on multiple different production lines due to reasons such as different equipment, even when the same process parameters are used, which will affect the conversion efficiency of the solar cell.

[0048] The existing solution is to adjust the process parameters of each production line and optimize the process to obtain a solar cell that meets the requirements of the cell conversion efficiency. However, adjusting the refractive index and thickness can only blindly adjust the overall laminated film, and cannot adjust the refractive index and thickness of each single-layer film in the laminate. The adjustment efficiency is often not optimal, and it is time-consuming and laborious.

[0049] At the same time, among the many process parameters for preparing the thin film, an important parameter is the silicon-nitrogen ratio of the thin film, which has the most significant influence on the refractive index of the thin film. The refractive index is closely related to the antireflection effect and passivation effect of the thin film. Utilizing this characteristic, by fixing the process parameters, especially the silicon-nitrogen ratio, adjusting the deposition time, obtaining the required film thickness condition, measuring the refractive index by ellipsometer, and then calculating the film thickness of the single-layer film according to the process parameters, finally obtaining the film thickness and refractive index of the single-layer film in the laminated film.

[0050] In order to provide a more scientific basis and guidance for process optimization, the present invention designs a single-layer film with reference to the cell product, and tests the thickness and refractive index of each single-layer film, calculates the thickness of the single-layer film in the cell stacked film, and obtains the refractive index of different single-layer films through testing. The stacked film includes film layers 1, 2, 3, ... n deposited in sequence, and the thickness of the stacked film cell is 60-90nm. If the thickness and refractive index of film layer 1 need to be tested, edit a test process for film layer 1, delete film layers 2 / 3 / ...n, and obtain the test process for film layer 1. The steps for testing the remaining film layers are analogous.

[0051] Since the deposition process of the single-layer film sample is the same as that of the single-layer film in the battery product laminate film, the refractive index of the sample single-layer film tested by the ellipsometer can characterize the refractive index of the single-layer film in the actual battery product laminate film. In addition, the refractive index of the single film layer of different production lines can be adjusted in a targeted manner, and the difference between the refractive indices of the single film layers of different production lines can be adjusted, so that the battery cells produced by different production lines meet the requirements and obtain better conversion efficiency.

[0052] The specific application methods are as follows:

[0053] Through process debugging, battery cell products that meet the requirements are produced, and this solution is used to test the thickness and refractive index of each film layer of the battery cells that meet the requirements to obtain standard data; when expanding production, first use the test piece to perform the above test on the new production line to obtain test data; compare the test data with the standard data obtained previously, and when there is a difference between the two data, adjust the process parameters of the single-layer film of the new production line with the difference accordingly to form the actual process of the new production line; use the actual process obtained on the new production line to produce battery cell products that meet the requirements, thereby improving production efficiency.

[0054] The following is a detailed description of a method for testing the thickness and refractive index of a single layer in a laminated film provided by the present invention in conjunction with the accompanying drawings.

[0055] Example 1

[0056] A method for testing the refractive index of a single-layer film in a laminated film cell, the laminated film cell comprising a single crystal silicon substrate and three layers of silicon nitride films deposited sequentially on the back of the single crystal silicon substrate. In this embodiment, the back of the single crystal silicon substrate is a polished surface, and the surface microstructure of the polished surface is a tower base structure. Three layers of silicon nitride films are deposited sequentially on the back of the single crystal silicon substrate to form a laminated film, the thickness of each silicon nitride single layer film is less than 60nm, and the thickness of the obtained laminated film cell is 60-90nm.

[0057] The method for testing the refractive index of a single-layer film in the laminated film cell comprises the following steps:

[0058] Step 1: Provide a silicon substrate for the test cell; using the deposition process of a single layer film when preparing a stacked film cell, deposit a silicon nitride film of a single layer film on the back of the silicon substrate of the test cell as a sample film.

[0059] In this embodiment, the deposition time in the deposition process of the sample film adopts the calculated theoretical deposition time T. The calculation steps of the theoretical deposition time T include:

[0060] Preset the first thickness D. The first thickness D is the preset thickness of the sample film of the single layer film deposited on the silicon substrate of the test cell; based on the first thickness D, calculate the theoretical deposition time T. Among them, the theoretical deposition time T is the time required to deposit a sample film with a thickness of the first thickness D on the silicon substrate of the test cell. In this embodiment, the preset first thickness D is specifically: in order to absorb the blue band with the most energy in sunlight, the thickness of the stacked film cells prepared by the first production line and the second production line during application is 60 - 90 nm. Therefore, the test method tries to simulate the test conditions of the stacked film cells prepared by the first production line and the second production line as much as possible to reduce the error of ellipsometer testing. The thickness of the sample film of the single layer film to be tested is designed in the range of 60 - 90 nm. At the same time, considering factors such as the absorption of the antireflection film, surface passivation, and bulk passivation, find the best balance value among these changes. Finally, design the single layer film sample to have the first thickness D = 74 ± 15 nm;

[0061] In this embodiment, calculating the theoretical deposition time T based on the first thickness D is specifically: calculate the theoretical deposition time T required for the single layer film sample film according to the formula T = D / F. Among them, F is the empirical deposition rate of tube PECVD in the deposition process of a single layer film when preparing a stacked film cell. In this embodiment, the specific value of F is 0.15 nm / s. Substitute F = 0.15 nm / s into the formula T = D / F to calculate the theoretical deposition time T = 74 / 0.15 ≈ 493 S;

[0062] In this embodiment, depositing a sample film of a single layer film on the back of the silicon substrate of the test cell is specifically: using the deposition process of a single layer film when preparing a stacked film cell, using tube PECVD as the deposition equipment, and depositing on the back of the silicon substrate of the test cell for 493 S (the calculated theoretical deposition time T) at a deposition rate of 0.15 nm / s (the empirical deposition rate F of the deposition process of a single layer film when preparing a stacked film cell) to obtain a single layer film sample film.

[0063] Step 2: Test the refractive index of the sample film, and obtain the refractive index of the single layer film in the stacked film cell based on the refractive index of the sample film.

[0064] In this embodiment, testing the refractive index of the sample film is specifically: using a full-spectrum ellipsometer to test that the refractive index of the sample film of the single layer film obtained in Step 1 is n1 = 2.22;

[0065] Step 3: Test the refractive indices of the other two single-layer silicon nitride films of the stacked film: Repeat Steps 1-2 to test the refractive indices of the other two single-layer silicon nitride films in the stacked film. According to the above test method, the refractive index n2 of the second single-layer silicon nitride film is obtained as 2.18; the refractive index n3 of the third single-layer silicon nitride film is 2.07.

[0066] Example 2

[0067] A method for testing the refractive index of a single layer film in a stacked film solar cell. The stacked film solar cell includes a monocrystalline silicon substrate and three layers of silicon nitride films and two layers of silicon oxynitride films sequentially deposited on the front surface of the monocrystalline silicon substrate. The front surface of the monocrystalline silicon substrate is a textured surface, and the microscopic structure of the textured surface is a pyramid structure. In this example, three layers of silicon nitride films and two layers of silicon oxynitride films are sequentially deposited from bottom to top on the front surface of the monocrystalline silicon substrate to form a stacked film. The thickness of each single-layer silicon nitride film or single-layer silicon oxynitride film is less than 60 nm, and the thickness of the obtained stacked film solar cell is 60-90 nm.

[0068] The method for testing the refractive index of a single layer film in the stacked film solar cell includes the following steps:

[0069] Step 1: Provide a silicon substrate for the test cell; Using the deposition process of the single layer film when preparing the stacked film solar cell, deposit a single layer film sample film on the front surface of the silicon substrate of the test cell.

[0070] In this example, the deposition time in the deposition process of the sample film uses the calculated theoretical deposition time T. The calculation steps of the theoretical deposition time T include:

[0071] Preset a first thickness D. The first thickness D is the preset thickness of the sample film of the single layer film deposited on the silicon substrate of the test cell; Based on the first thickness D, calculate the theoretical deposition time T, where the theoretical deposition time T is the time required to deposit a sample film with a thickness of the first thickness D on the silicon substrate of the test cell.

[0072] In this example, the preset first thickness D is specifically: In order to absorb the blue band with the most energy in sunlight, the thickness of the stacked film solar cells prepared by the first production line and the second production line during application is 60-90 nm. Therefore, the test method tries to simulate the test conditions of the stacked film solar cells prepared by the first production line and the second production line, reduce the error of ellipsometer testing, and design the thickness of the single layer film to be tested in the range of 60-90 nm. At the same time, considering factors such as the absorption of the antireflection film, surface passivation, and bulk passivation, find the best balance value among these changes. Finally, design the single layer film sample to have a first thickness D = 74 ± 15 nm;

[0073] In this embodiment, the theoretical deposition time T is calculated based on the first thickness D. Specifically, the theoretical deposition time T required for the single-layer film sample film is calculated according to the formula T = D / F, where F is the empirical deposition rate of the tube PECVD in the deposition process of the single-layer film when preparing the stacked film solar cell. In this embodiment, the specific value of F is 0.08 nm / s. Substituting F = 0.08 nm / s into the formula T = D / F, the theoretical deposition time T = 74 / 0.08 ≈ 925 S;

[0074] In this embodiment, the sample film of the single-layer film is deposited on the front side of the silicon substrate of the test solar cell. Specifically, the deposition process of the single-layer film when preparing the stacked film solar cell is adopted, with the tube PECVD as the deposition equipment, and the sample film of the single-layer film is deposited on the front side of the silicon substrate of the test solar cell at a deposition rate of 0.08 nm / s (the empirical deposition rate F of the deposition process of the single-layer film when preparing the stacked film solar cell) for 925 S (the calculated theoretical deposition time T), to obtain the single-layer film sample.

[0075] Step 2: Test the refractive index of the sample film, and obtain the refractive index of the single-layer film in the stacked film solar cell based on the refractive index of the sample film.

[0076] In this embodiment, testing the refractive index of the sample film specifically includes: using a full-spectrum ellipsometer to test that the refractive index of the sample film of the single-layer film obtained in Step 1 is n1 = 2.29; Step 3: Test the refractive indices of the other two single-layer silicon nitride films and two silicon oxynitride films on the front side of the stacked film: Repeat Steps 1-2 to test the refractive indices of the other two single-layer silicon nitride films and two silicon oxynitride films in the stacked film. According to the above test method, the refractive index n2 = 2.19 of the second single-layer silicon nitride film, the refractive index n3 = 2.1 of the third single-layer silicon nitride film, the refractive index n4 = 1.93 of the fourth silicon oxynitride film, and the refractive index n5 = 1.75 of the fifth silicon oxynitride film are respectively tested.

[0077] Example 3

[0078] A method for testing the refractive index and thickness of a single-layer film in a stacked film solar cell. The stacked film solar cell includes a single-crystalline silicon substrate and three silicon nitride films sequentially deposited on the back side of the single-crystalline silicon substrate. The back side of the single-crystalline silicon substrate is a polished surface, and the microscopic structure of the polished surface is a tower base structure. In this embodiment, the solar cell includes a single-crystalline silicon substrate, and three silicon nitride films are sequentially deposited on the back side of the single-crystalline silicon substrate. The thickness of each single-layer silicon nitride film is less than 60 nm, and the thickness of the obtained stacked film solar cell is 60-90 nm.

[0079] The method for testing the refractive index of the single-layer film in the stacked film solar cell includes the following steps:

[0080] Step 1: Provide a test cell silicon substrate; using the deposition process of a single layer film when preparing a stacked film cell, deposit a single layer of silicon nitride film on the back of the test cell silicon substrate as a sample film.

[0081] In this embodiment, the deposition time in the deposition process of the sample film uses the calculated theoretical deposition time T. The calculation steps of the theoretical deposition time T include:

[0082] Preset a first thickness D. The first thickness D is the preset thickness of the sample film of the single layer film deposited on the test cell silicon substrate; based on the first thickness D, calculate the theoretical deposition time T. Among them, the theoretical deposition time T is the time required to deposit a sample film with a thickness of the first thickness D on the test cell silicon substrate;

[0083] In this embodiment, specifically presetting the first thickness D: In order to absorb the blue band with the most energy in sunlight, the thickness of the stacked film cells prepared by the first production line and the second production line during application is 60 - 90 nm. Therefore, the test method tries to simulate the test conditions of the stacked film cells prepared by the first production line and the second production line, reduce the error of ellipsometer testing, and design the thickness of the single layer film to be tested in the range of 60 - 90 nm. At the same time, considering factors such as the absorption of the antireflection film, surface passivation, and bulk passivation, find the best balance value among these changes. Finally, design the single layer film sample film to have a first thickness D = 74 ± 15 nm;

[0084] In this embodiment, calculating the theoretical deposition time T based on the first thickness D is specifically: Calculate the theoretical deposition time T required for the single layer film sample film according to the formula T = D / F. Among them, F is the empirical deposition rate of tube PECVD in the deposition process of a single layer film when preparing a stacked film cell. In this embodiment, the specific value of F is 0.15 nm / s. Substitute F = 0.08 nm / s into the formula T = D / F to calculate the theoretical deposition time T = 74 / 0.15 ≈ 493 S;

[0085] In this embodiment, depositing a sample film of a single layer film on the back of the test cell silicon substrate is specifically: Using the deposition process of a single layer film when preparing a stacked film cell, using tube PECVD as the deposition equipment, deposit at a deposition rate of 0.15 nm / s (the empirical deposition rate F of the deposition process of a single layer film when preparing a stacked film cell) on the back of the test cell silicon substrate for 493 S (the calculated theoretical deposition time T) to obtain a single layer film sample film.

[0086] Step 2: Test the refractive index and test thickness of the sample film, and obtain the refractive index and thickness of the single layer film in the stacked film cell based on the refractive index and test thickness of the sample film.

[0087] In this embodiment, the refractive index and thickness of the test sample film are specifically as follows: Using a full-spectrum ellipsometer, the refractive index of the sample film of the single-layer film obtained in step 1 is n1 = 2.22, and the measured thickness A = 72.5 nm;

[0088] Step 3: Calculate the thickness d1 of the single-layer silicon nitride film in the stacked film.

[0089] In this embodiment, the calculation of the thickness d1 of the single-layer silicon nitride film in the stacked film is specifically as follows:

[0090] Based on the measured thickness A, the deposition rate f is calculated, specifically: f is calculated by the formula f = A / T, where T is the theoretical time required to deposit a sample film with a thickness of the first thickness D on the test cell silicon substrate, and f = 72.5 / 493 nm / s is calculated;

[0091] Based on the deposition rate f, the thickness dn of the single-layer film is calculated, specifically: The thickness of the single-layer silicon nitride film in the stacked film is obtained according to the formula dn = f × tn, where f is the calculated deposition rate and tn is the deposition time for depositing the single-layer film when preparing the stacked film cell. In this embodiment, tn = 100 S, and d1 = f × tn = 72.5 / 493 × 100 = 14.7 nm is calculated.

[0092] Step 4: Test the refractive index and thickness of the other two single-layer silicon nitride films in the stacked film: Repeat steps 1-3 to test and calculate the refractive index and thickness of the other two single-layer silicon nitride films in the stacked film. According to the above test method, the refractive index n2 = 2.18 and the thickness d2 = 45 nm of the second single-layer silicon nitride film are respectively measured; the refractive index n3 = 2.07 and the thickness d3 = 52 of the third single-layer silicon nitride film.

[0093] Example 4

[0094] A method for testing the refractive index and thickness of a single-layer film in a stacked film cell, the stacked film cell includes a single-crystalline silicon substrate and three layers of silicon nitride films and two layers of silicon oxynitride films sequentially deposited on the front side of the single-crystalline silicon substrate. The front side of the single-crystalline silicon substrate is a textured surface, and the microscopic structure of the textured surface is a pyramid structure. In this embodiment, the cell includes a single-crystalline silicon substrate, and three layers of silicon nitride films and two layers of silicon oxynitride films are sequentially deposited on the front side of the single-crystalline silicon substrate from bottom to top to form a stacked film. The thickness of the single-layer silicon nitride single-layer film or the single-layer silicon oxynitride single-layer film is less than 60 nm, and the thickness of the obtained stacked film cell is 60-90 nm.

[0095] The method for testing the refractive index of the single-layer film in the stacked film cell includes the following steps:

[0096] Step 1: Provide a test cell silicon substrate; using the deposition process of a single layer film when preparing a stacked film cell, deposit a sample film of the single layer film on the front side of the test cell silicon substrate.

[0097] In this embodiment, the deposition time in the deposition process of the sample film adopts the calculated theoretical deposition time T. The calculation steps of the theoretical deposition time T include:

[0098] Preset a first thickness D. The first thickness D is the preset thickness of the sample film of the single layer film deposited on the test cell silicon substrate; based on the first thickness D, calculate the theoretical deposition time T, where the theoretical deposition time T is the time required to deposit a sample film with a thickness of the first thickness D on the test cell silicon substrate;

[0099] In this embodiment, specifically presetting the first thickness D: In order to absorb the blue band with the most energy in sunlight, the thickness of the stacked film cells prepared by the first production line and the second production line during application is 60 - 90 nm. Therefore, the test method tries to simulate the test working conditions of the stacked film cells prepared by the first production line and the second production line, reduce the error of ellipsometer testing, and design the thickness of the single layer film to be tested in the range of 60 - 90 nm. At the same time, considering factors such as the absorption of the antireflection film, surface passivation, and bulk passivation, find the best balance value among these changes. Finally, design the single layer film sample film to have a first thickness D = 74 ± 15 nm;

[0100] In this embodiment, calculating the theoretical deposition time T based on the first thickness D is specifically: Calculate the theoretical deposition time T required for the single layer film sample according to the formula T = D / F, where F is the empirical deposition rate of the tube type PECVD in the deposition process of the single layer film when preparing the stacked film cell. In this embodiment, the specific value of F is 0.08 nm / s. Substitute F = 0.08 nm / s into the formula T = D / F to calculate the theoretical deposition time T = 74 / 0.08 ≈ 925 S;

[0101] In this embodiment, depositing a sample film of the single layer film on the front side of the test cell silicon substrate is specifically: Using the deposition process of the single layer film when preparing the stacked film cell, taking the tube type PECVD as the deposition equipment, deposit for 925 S (the calculated theoretical deposition time T) on the front side of the test cell silicon substrate at a deposition rate of 0.08 nm / s (the empirical deposition rate F of the deposition process of the single layer film when preparing the stacked film cell) to obtain a single layer film sample.

[0102] Step 2: Test the refractive index and the test thickness of the sample film, and obtain the refractive index and thickness of the single layer film in the stacked film cell based on the refractive index of the sample film.

[0103] In this embodiment, the refractive index of the test sample film is specifically as follows: The refractive index of the sample film of the single-layer film obtained in step 1 is measured using a full-spectrum ellipsometer as n1 = 2.29, and the measured thickness A = 75 nm;

[0104] Step 3: Calculate the thickness d1 of the single-layer silicon nitride film in the stacked film.

[0105] In this embodiment, the calculation of the thickness d1 of the single-layer silicon nitride film in the stacked film is specifically as follows:

[0106] Based on the measured thickness A, the actual deposition rate f is calculated, specifically: f is calculated by the formula f = A / T, where T is the theoretical time required to deposit a sample film with a thickness of the first thickness D on the test cell silicon substrate, and f = 75 / 925 nm / s is calculated;

[0107] Based on the actual deposition rate f, the thickness dn of the single-layer film is calculated, specifically: The thickness of the single-layer silicon nitride film in the stacked film is obtained according to the formula dn = f × tn, where f is the calculated deposition rate and tn is the deposition time for depositing the single-layer film when preparing the stacked film cell. In this embodiment, tn = 150 S, and d1 = f × t1 = 75 / 925 × 150 = 12 nm is calculated.

[0108] Step 4: Measure the refractive indices and thicknesses of the other two single-layer silicon nitride films and two silicon oxynitride films on the front side of the stacked film: Repeat steps 1-3 to measure the refractive indices and thicknesses of the other two single-layer silicon nitride films and two silicon oxynitride films in the stacked film. According to the above measurement method, the refractive index n2 = 2.19 and the thickness d2 = 18 nm of the second single-layer silicon nitride film are measured respectively; the refractive index n3 = 2.1 and the thickness d3 = 23 nm of the third single-layer silicon nitride film; the refractive index n4 = 1.93 and the thickness d4 = 15 nm of the fourth silicon oxynitride film; the refractive index n5 = 1.75 and the thickness d5 = 17 nm of the fifth silicon oxynitride film.

[0109] Example 5

[0110] A process debugging method for a stacked film cell includes the following steps:

[0111] S1. According to the method of Example 1 or Example 2, measure the first refractive index of a certain single-layer film in the stacked film cell prepared on the first production line. The single-layer film in the stacked film cell is prepared using the first deposition process;

[0112] S2. Test the second refractive index of the single-layer film in the laminated film solar cell prepared on the second production line during the expansion of the production line according to the method of Embodiment 1 or Embodiment 2. The single-layer film in the laminated film solar cell is prepared by the first deposition process;

[0113] S3. Compare the first refractive index with the second refractive index, and adjust the deposition process of the second production line after the expansion based on the difference between the first refractive index and the second refractive index;

[0114] S4. Produce qualified solar cell products on the newly expanded production line using the deposition process of the second production line debugged in S3.

[0115] Embodiment 6

[0116] A process debugging method for laminated film solar cells, comprising the following steps:

[0117] S1. Test the first refractive index and the first thickness of the single-layer film in the laminated film solar cell prepared on the first production line according to the method of Embodiment 3 or Embodiment 4. The single-layer film in the laminated film solar cell is prepared by the first deposition process;

[0118] S2. Test the second refractive index and the second thickness of the single-layer film in the laminated film solar cell prepared on the second production line during the expansion of the production line according to the method of Embodiment 3 or Embodiment 4. The single-layer film in the laminated film solar cell is prepared by the first deposition process;

[0119] S3. Compare the first refractive index with the second refractive index, and compare the first thickness with the second thickness. Adjust the deposition process of the second production line after the expansion based on the difference between the first refractive index and the second refractive index and the difference between the first thickness and the second thickness;

[0120] S4. Produce qualified solar cell products on the newly expanded production line using the deposition process of the second production line debugged in S3.

[0121] Through process debugging, the production efficiency of the expanded production line is improved, the optical path is effectively managed, the anti-PID performance and reliability of the module are enhanced, the conversion efficiency of the solar cell is increased by 0.1%, and the annual economic benefit of 5GW is more than 600W RMB.

[0122] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0123] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for testing the parameters of a single layer film in a stacked film solar cell, which is applied to the process debugging method of the stacked film solar cell. The parameters of the single layer film include the refractive index of the single layer film, and it is characterized in that, The test method includes the following steps: Provide a silicon substrate of a test cell; using the deposition process of the single layer film when preparing the stacked film cell, deposit a sample film of the single layer film on at least one side of the silicon substrate of the test cell. Among them, the deposition time in the deposition process of the sample film uses the calculated theoretical deposition time T. The calculation steps of the theoretical deposition time T include: Preset a first thickness D, where the first thickness D is the preset thickness of the sample film of the single layer film deposited on the silicon substrate of the test cell; Based on the first thickness D, calculate the theoretical deposition time T, where the theoretical deposition time T is the time required to deposit the sample film with a thickness of the first thickness D on the silicon substrate of the test cell; Test the refractive index of the sample film, and obtain the refractive index of the single layer film in the stacked film cell based on the refractive index of the sample film.

2. The testing method according to claim 1, characterized in that, The parameters of the single layer film also include the thickness of the single layer film. After depositing the sample film of the single layer film on at least one side of the silicon substrate of the test cell, the following steps are also included: Test the test thickness A of the sample film; Calculate the deposition rate f based on the test thickness A; Calculate the thickness dn of the single layer film based on the calculated deposition rate f.

3. The test method according to any one of claims 1-2, characterized in that, The front or back of the silicon substrate of the test cell is a polished surface or a textured surface, and the sample film is deposited on the polished surface or the textured surface of the silicon substrate of the test cell.

4. The test method according to claim 3, wherein The calculating the theoretical deposition time T based on the first thickness D includes: Calculate the required theoretical deposition time T of the single layer film sample according to the formula T = D / F, where F is the empirical deposition rate in the deposition process of the single layer film when preparing the stacked film cell.

5. The test method according to claim 4, wherein The deposition rate F on the polished surface of the silicon substrate of the test cell is 0.1 - 0.2 nm / s, and the deposition rate F on the textured surface of the silicon substrate of the test cell is 0.05 - 0.1 nm / s.

6. The testing method according to claim 3, wherein Calculating the deposition rate f based on the test thickness A includes: Calculate the deposition rate f according to the formula f = A / T; The calculating the thickness dn of the single layer film based on the deposition rate f includes: Obtain the thickness of the single layer film according to the formula dn = f × tn, where f is the deposition rate calculated according to the test thickness A of the single layer sample film and the theoretical time T, and tn is the deposition time of depositing the single layer film when preparing the stacked film cell.

7. The test method according to claim 3, wherein The thickness of the stacked film cell is 60 - 90 nm, the single layer film is a silicon nitride film, a silicon oxide film or a silicon oxynitride film; the thickness of the single layer film is less than 60 nm, and the first thickness D is 74 ± 15 nm.

8. Application of the test method according to any one of claims 2 - 7 in testing the thickness and / or refractive index of the single layer film in the stacked film cell.

9. A process debugging method for a laminated film battery cell, wherein the process debugging method is a method of applying the process of the first production line to the process debugging of the second production line, and is characterized in that, Includes the following steps: S1. Test and obtain the first refractive index and / or the first thickness of at least one single layer film in the stacked film cell prepared on the first production line. The first refractive index and / or the first thickness are measured by the test method according to any one of claims 2 - 7, and at least one single layer film in the stacked film cell is prepared by the first deposition process; S2. Test and obtain the second refractive index and / or the second thickness of at least one monolayer film in the laminated film solar cell prepared on the second production line during the expansion of the production line. The second refractive index and / or the second thickness are measured by the test method according to any one of claims 2-7, and at least one monolayer film in the laminated film solar cell is prepared by the first deposition process; S3. Compare the first refractive index with the second refractive index, and / or compare the first thickness with the second thickness, and adjust the deposition process of the second production line after the expansion based on the difference between the first refractive index and the second refractive index and / or the difference between the first thickness and the second thickness.

10. The debugging method according to claim 9, wherein The laminated film solar cell includes a silicon substrate of the solar cell, a back laminated film, and a front laminated film. The back laminated film includes three sequentially deposited silicon nitride layers; the front laminated film includes three sequentially deposited silicon nitride layers and two sequentially deposited silicon oxynitride layers.

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