Method for intelligent regulation of sheet resistance and film thickness of heterojunction battery by tco device

Abstract

The present application relates to a kind of TCO equipment intelligent regulation and control heterojunction cell sheet resistance and film thickness method, belong to solar cell manufacturing technical field.It includes: the silicon wafer to be detected is placed on carrier plate and is transported to detection platform;Detection platform detects the sheet resistance of the silicon wafer to be detected and the film thickness of transparent conductive film;Control end determines whether the sheet resistance of the battery and / or the film thickness of transparent conductive film prepared by current transparent conductive film deposition equipment exceeds their respective quality process control range according to detection result;If yes, correct the oxygen flow and / or output power of transparent conductive film deposition equipment;The transparent conductive film of the silicon wafer transported subsequently is deposited according to the oxygen flow and / or output power after correction.The present application provides a kind of method for intelligently regulating and controlling heterojunction cell sheet resistance and TCO film thickness, and the oxygen flow and output power of transparent conductive film deposition equipment are regulated and controlled by the method, which saves manpower, slurry and cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cell manufacturing, and in particular to a method for intelligently regulating the sheet resistance and film thickness of a heterojunction cell by a TCO device. BACKGROUND

[0002] Heterojunction cells (HJT) are a very important development direction of high-efficiency solar cells due to their symmetrical structure and ability to well passivate the surface, and have obvious advantages in open-circuit voltage. Transparent conductive thin film (TCO thin film) is a key process in the production of heterojunction cells, and the thin film has good light transmission, conductivity, and can reduce light reflection. In recent years, the most commonly used methods for preparing TCO thin films are magnetron sputtering (PVD) and reactive plasma deposition, especially magnetron sputtering, which is developing rapidly because this method has the following advantages: uniform film thickness, easy to control; stable plating process, good repeatability of thin film quality; long target life, continuous production; high atomic kinetic energy in the sputtering process, strong adhesion of the thin film to the substrate.

[0003] As the mainstream development technology for depositing transparent conductive thin films at present, the PVD device is developing towards large capacity and low cost along with the market demand for capacity and cost. From the original 1250 pieces / hour, it has developed to 4000 pieces / hour, and now more than 8000 pieces / hour have appeared. However, with the increase of capacity, the design standard of the carrier plate also increases. In order to meet the requirements of the PVD device for capacity, a large size specification of the carrier plate is needed, and the use of a large size specification of the carrier plate inevitably leads to the increase of the size of the entire cavity of the PVD device. Therefore, the control of the uniformity of the sheet resistance of the heterojunction cell, the uniformity of the film thickness of the TCO thin film, and the deformation of the carrier plate has become more difficult. The sheet resistance uniformity and the film thickness uniformity are important process data in the production line control process, which directly affect the conversion efficiency of the solar cell product, and the change of the film thickness also affects the appearance of the cell after plating the TCO thin film. Currently, the technical personnel generally rely on experience to adjust the process parameters of the transparent conductive thin film deposition device (referred to as TCO device), such as oxygen flow and output power, to adjust the sheet resistance of the heterojunction cell and the film thickness of the TCO thin film.

[0004] However, the manual adjustment of the process parameters of the transparent conductive thin film deposition device consumes manpower and is not accurate in the regulation of the sheet resistance and the film thickness. In addition, the sheet resistance and the film thickness need to be monitored at regular intervals during the continuous production process, which consumes manpower and may cause batch rework and non-compliant wafer sources to enter the screen process, resulting in a large amount of slurry consumption in the printing process, causing a large amount of cost waste, and affecting the conversion efficiency of the cell wafer, which may easily cause batch yield problems. SUMMARY

[0005] To solve the above technical problems, the present application provides a method for intelligently regulating the sheet resistance and film thickness of a heterojunction battery by a TCO device. The technical solution is as follows:

[0006] A method for intelligently regulating the sheet resistance and film thickness of a heterojunction battery by a TCO device, comprising the following steps:

[0007] S1, placing the silicon wafer to be detected containing a transparent conductive film prepared by a transparent conductive film deposition device on a carrier plate and transporting it to a detection platform;

[0008] S2, detecting the sheet resistance of the silicon wafer to be detected and the film thickness of the transparent conductive film by the detection platform, and sending the detection results to the control end of the transparent conductive film deposition device;

[0009] S3, determining whether the sheet resistance of the battery and / or the film thickness of the transparent conductive film currently prepared by the transparent conductive film deposition device exceeds the respective corresponding quality process control range according to the detection results;

[0010] S4, if the control end determines that the sheet resistance of the battery and / or the film thickness of the transparent conductive film currently prepared exceeds the respective corresponding quality process control range, correcting the oxygen flow of the transparent conductive film deposition device to adjust the sheet resistance of the subsequent battery, and / or correcting the output power of the transparent conductive film deposition device to adjust the film thickness of the subsequent transparent conductive film;

[0011] S5, sending the corrected oxygen flow and / or output power to the transparent conductive film deposition device by the control end;

[0012] S6, depositing the transparent conductive film of the silicon wafer transported subsequently by the transparent conductive film deposition device according to the corrected oxygen flow and / or the corrected output power.

[0013] Optionally, the step of correcting the oxygen flow of the transparent conductive film deposition device to adjust the sheet resistance of the subsequent battery in S4 comprises the following steps:

[0014] S4-1, correcting the oxygen flow of the upper cathode of the transparent conductive film deposition device to adjust the sheet resistance of the upper cathode of the subsequent battery according to the difference between the actual sheet resistance of the upper cathode and the target sheet resistance of the upper cathode;

[0015] S4-2, correcting the oxygen flow of the lower cathode of the transparent conductive film deposition device to adjust the sheet resistance of the lower cathode of the subsequent battery according to the difference between the actual sheet resistance of the lower cathode and the target sheet resistance of the lower cathode.

[0016] Optionally, the step of correcting the output power of the transparent conductive film deposition device to adjust the film thickness of the subsequent transparent conductive film in S4 comprises the following steps:

[0017] S4.1, adjusting the upper cathode film thickness of the subsequent transparent conductive film by correcting the output power of the upper cathode of the transparent conductive film deposition equipment according to the difference between the actual film thickness of the upper cathode and the target film thickness of the upper cathode;

[0018] S4.2, adjusting the lower cathode film thickness of the subsequent transparent conductive film by correcting the output power of the lower cathode of the transparent conductive film deposition equipment according to the difference between the actual film thickness of the lower cathode and the target film thickness of the lower cathode.

[0019] Optionally, the S4-1 sets the resistance value of the target sheet resistance of the upper cathode as X1 and the resistance value of the actual sheet resistance of the upper cathode as X2 when correcting the oxygen flow of the upper cathode of the transparent conductive film deposition equipment according to the difference between the actual sheet resistance of the upper cathode and the target sheet resistance of the upper cathode, and the difference between the actual sheet resistance of the upper cathode and the target sheet resistance of the upper cathode is ΔX=X2-X1, and the oxygen flow of the upper cathode is set as O 2-up Therefore, when correcting the oxygen flow of the upper cathode, the following cases are included:

[0020] A, when -5≤ΔX≤5, the oxygen flow O 2-up of the upper cathode is unchanged;

[0021] B, when -20≤ΔX<-5 or 5<ΔX≤20, the size of the oxygen flow is adjusted according to the formula ΔO 2-up =(0.1-0.3)×(ΔX / 5); wherein (ΔX / 5) represents the positive integer part of ΔX / 5; when ΔX<0, (0.1-0.3) takes the positive sign, indicating that the oxygen flow of the upper cathode needs to be increased; when ΔX>0, (0.1-0.3) takes the negative sign, indicating that the oxygen flow of the upper cathode needs to be reduced;

[0022] C, when ΔX<-20 or ΔX>20, the control end determines that the error is out of range and performs alarm prompting.

[0023] Optionally, the S4.1 sets the size of the target film thickness of the upper cathode as T up-1 and the size of the actual film thickness of the upper cathode as T up-2 when correcting the output power of the upper cathode of the transparent conductive film deposition equipment according to the difference between the actual film thickness of the upper cathode and the target film thickness of the upper cathode, and the difference between the actual film thickness of the upper cathode and the target film thickness of the upper cathode is ΔT up =T up-2 -T up-1 , the current output power of the upper cathode is set as P up1 , and the corrected output power of the upper cathode is set as P up2 Therefore, when correcting the output power of the upper cathode, the following cases are included:

[0024] a, when -3≤ΔT up≤3, the output power of the upper cathode is corrected according to the formula P up2 unchanged;

[0025] b, when -15≤ΔT up < -3 or 3 < ΔT up ≤15, the output power of the upper cathode is corrected according to the formula P up2 = ±P up1 × (T up-1 / T up-2 ); wherein, when ΔT up <0, P up2 takes the positive sign, indicating that the output power of the upper cathode needs to be increased; when ΔT up >0, P up2 takes the negative sign, indicating that the output power of the upper cathode needs to be reduced;

[0026] c, when ΔT up < -15 or ΔT up >15, the control end determines that the error exceeds the range, and an alarm is prompted.

[0027] Optionally, the S6, the transparent conductive film deposition equipment deposits the transparent conductive film of the silicon wafer transported subsequently according to the corrected oxygen flow and / or the corrected output power, and the method further comprises:

[0028] S7, the square resistance of the silicon wafer transported subsequently and deposited according to the corrected oxygen flow and / or the corrected output power and the film thickness of the transparent conductive film are sampled, and it is judged again whether the square resistance and / or the film thickness of the transparent conductive film of the silicon wafer to be detected sampled exceeds the corresponding quality process control range.

[0029] Optionally, the S2, the detection platform detects the square resistance and the film thickness of the transparent conductive film of the silicon wafer to be detected, comprising the following steps:

[0030] S21, the detection platform selects a plurality of representative battery pieces on the carrier plate as the silicon wafer to be detected;

[0031] S22, the detection platform detects the square resistance of each representative silicon wafer to be detected, calculates the average value of the square resistance of each silicon wafer to be detected, and takes the average value of the square resistance as the square resistance detection result;

[0032] S23, the detection platform detects the film thickness of the transparent conductive film of each representative silicon wafer to be detected, calculates the average value of the film thickness of each transparent conductive film, and takes the average value of the film thickness of the transparent conductive film as the film thickness detection result.

[0033] Optionally, the plurality of representative battery pieces on the carrier plate include the battery pieces at the edges and in the middle of the first row, the battery pieces at the edges and in the middle of the last row, and the battery pieces at the edges and in the middle of the middle row of the carrier plate.

[0034] All the above optional technical solutions can be combined arbitrarily, and the application does not detail the structure after combination.

[0035] Through the above scheme, the beneficial effects of the application are as follows:

[0036] By detecting the sheet resistance of the to-be-detected silicon wafer and the film thickness of the transparent conductive film through the detection platform, the control end determines whether the sheet resistance of the battery and / or the film thickness of the transparent conductive film prepared by the transparent conductive film deposition device currently exceeds the quality process control range corresponding to each of them according to the detection result, and adjusts the sheet resistance of the subsequent battery and the film thickness of the TCO film by correcting the oxygen flow and output power of the transparent conductive film deposition device according to the determination result, thereby providing a method for intelligently regulating the sheet resistance and TCO film thickness of the heterojunction battery. The method intelligently regulates the oxygen flow and output power of the transparent conductive film deposition device to regulate the sheet resistance of the heterojunction battery and the film thickness of the TCO film, respectively, which not only saves manpower, but also can find that the wafer source that does not meet the control standard enters the screen process in time, thereby saving the paste and cost, so as to avoid affecting the conversion efficiency of the battery wafer and improving the yield of the battery wafer.

[0037] The above description is only a summary of the technical solutions of the application. In order to more clearly understand the technical means of the application and can be implemented according to the content of the specification, the following will be described in detail with the preferred embodiments of the application and with the help of the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a flowchart of the application.

[0039] Figure 2 is a structure diagram of the detection platform in the application. DETAILED DESCRIPTION

[0040] The specific embodiments of the application will be further described in detail below in combination with the drawings and examples. The following examples are used to illustrate the application, but not to limit the scope of the application.

[0041] As shown in Figure 1 , the method for intelligently regulating the sheet resistance and film thickness of the heterojunction battery provided by the TCO device includes the following steps:

[0042] S1, the transparent conductive film deposition device prepares a to-be-detected silicon wafer containing a transparent conductive film, which is placed on a carrier plate and transported to a detection platform.

[0043] The transparent conductive film deposition device can be a magnetron sputtering device or a reactive plasma deposition device, but is not limited to these two devices. The silicon wafer to be detected is any batch of silicon wafer selected from silicon wafers plated with a transparent conductive film by the transparent conductive film deposition device.

[0044] Specifically, the preparation process of the silicon wafer containing a transparent conductive film can include the following steps:

[0045] i. The N-type monocrystalline silicon wafer is subjected to texturing treatment to form a pyramid texture, remove impurity particles and clean the surface, thereby obtaining a crystalline silicon substrate;

[0046] ii. A first intrinsic amorphous silicon layer and an N-doped layer are sequentially deposited on the upper surface of the crystalline silicon substrate by plasma chemical vapor deposition or catalytic chemical vapor deposition, wherein the thickness of the first intrinsic amorphous silicon layer is controlled to be 5-20 nm, and the thickness of the N-doped layer is controlled to be 5-30 nm; a second intrinsic amorphous silicon layer and a P-doped layer are sequentially deposited on the lower surface of the crystalline silicon substrate by plasma chemical vapor deposition or catalytic chemical vapor deposition, wherein the thickness of the second intrinsic amorphous silicon layer is controlled to be 5-20 nm, and the thickness of the P-doped layer is controlled to be 5-20 nm;

[0047] iii. A transparent conductive film with a thickness of 60-140 nm is deposited on the upper surface of the N-doped layer and the lower surface of the P-doped layer by PVD or RPD.

[0048] S2, the detection platform detects the sheet resistance of the silicon wafer to be detected and the film thickness of the transparent conductive film, and sends the detection results to the control end of the transparent conductive film deposition device.

[0049] The detection platform is equipped with a detector capable of detecting the sheet resistance of the silicon wafer and the film thickness of the transparent conductive film. The detector is located above the silicon wafer to be detected. The detector for detecting the film thickness and sheet resistance of the transparent conductive film can be in contact with the TCO film or not in contact during detection. If it is in contact, in order to prevent the middle hollow of the edge of the groove of the carrier plate from increasing the risk of breakage of the silicon wafer to be detected during contact, a lifting platform can be provided below the silicon wafer to be detected, or the silicon wafer to be detected can be grabbed and detected close to the detector. In addition, the detection platform also has a silicon wafer overturning function (such as a detection platform equipped with an overturning gripper), which overturns the silicon wafer to be detected to the back surface after detecting the sheet resistance and film thickness of the upper cathode (P surface) of the silicon wafer to be detected, and further detects the sheet resistance and film thickness of the lower cathode (N surface) of the silicon wafer to be detected. Of course, the silicon wafer can also be manually overturned.

[0050] For example, the detection platform can be a robot arm or a robot arm equipped with a detection device. Figure 2As shown, it is a structural schematic diagram of a detection platform. The detection platform comprises a support 1 and a detector 2, the detector 2 is connected with the support 1 and located above a carrier plate 3, and a silicon wafer 4 is placed on the carrier plate 3. The detector 2 integrates a device capable of detecting the square resistance of the battery and the film thickness of the TCO thin film.

[0051] Specifically, when the detection platform detects the square resistance of the silicon wafer to be detected and the film thickness of the transparent conductive thin film in S2, the following steps can be included:

[0052] S21, the detection platform selects several representative battery wafers on the carrier plate as the silicon wafer to be detected.

[0053] The reason for selecting several representative battery wafers as the silicon wafer to be detected is to reduce the workload of the detection platform while ensuring the referenceability of the detection results.

[0054] Considering that the square resistance and film thickness data can represent the entire carrier plate, the detection platform detection can adopt a 9-point detection method, that is, taking the positions of the front, middle and back three rows of the carrier plate, and measuring the left, middle and right of each row of the front, middle and back three rows. That is, the several representative battery wafers on the carrier plate include the battery wafers at the edges and in the middle of the first row, the battery wafers at the edges and in the middle of the last row, and the battery wafers at the edges and in the middle of the middle row of the carrier plate. When detecting, one carrier plate is set as one batch, and the distance from the process cavity of the transparent conductive thin film deposition device to the detection platform is calculated. For example, if the process cavity can accommodate 5 carrier plates to the detection platform, the silicon wafer to be detected can be selected once every 5 batches.

[0055] S22, the detection platform detects the square resistance of each representative silicon wafer to be detected, calculates the average value of the square resistance of each silicon wafer to be detected, and takes the average value of the square resistance as the square resistance detection result.

[0056] The embodiment of the present application takes the average value of the square resistance as the square resistance value of all the silicon wafers carried on the carrier plate in this detection process. The square resistance of each silicon wafer to be detected detected by the detection platform includes the upper cathode square resistance and the lower cathode square resistance, and the average value of the square resistance includes the average value of the upper cathode square resistance and the average value of the lower cathode square resistance.

[0057] S23, the detection platform detects the transparent conductive thin film thickness of each representative silicon wafer to be detected, calculates the average value of each transparent conductive thin film thickness, and takes the average value of the transparent conductive thin film thickness as the film thickness detection result.

[0058] The embodiment of the present application takes the average value of the transparent conductive thin film thickness as the transparent conductive thin film thickness of all the silicon wafers carried on the carrier plate in this detection process. The average value of the transparent conductive thin film thickness of each silicon wafer to be detected detected by the detection platform includes the average value of the upper cathode film thickness and the average value of the lower cathode film thickness.

[0059] Further, the detection platform sends the sheet resistance detection result and the film thickness detection result to a control end of the transparent conductive film deposition device. The control end is a device with computing function connected to the transparent conductive film deposition device through wired or wireless mode, such as a computer, a server, etc.

[0060] In addition, in order to discover the silicon wafer output not meeting the quality process control range in time, the step S2 can be periodically executed; or the detection can be performed according to the batch of silicon wafer entering the transparent conductive film deposition device, such as selecting a part of the silicon wafer to be detected for detection in each batch.

[0061] S3, the control end determines whether the sheet resistance of the battery currently prepared by the transparent conductive film deposition device and / or the film thickness of the transparent conductive film exceeds the respective corresponding quality process control range according to the detection result.

[0062] Specifically, the control end determines whether the sheet resistance of the battery currently prepared by the transparent conductive film deposition device exceeds the corresponding quality process control range according to the sheet resistance detection result, and determines whether the film thickness of the transparent conductive film of the battery currently prepared by the transparent conductive film deposition device exceeds the corresponding quality process control range according to the film thickness detection result.

[0063] In combination with the content of the above embodiment, when the average value of the upper cathode sheet resistance (the average value of the lower cathode sheet resistance) is less than the minimum value of the corresponding quality process control range of the upper cathode sheet resistance (the lower cathode sheet resistance) or greater than the maximum value of the corresponding quality process control range of the upper cathode sheet resistance (the lower cathode sheet resistance), the control end determines that the sheet resistance of the battery currently prepared exceeds the corresponding quality process control range. When the average value of the upper cathode film thickness (the average value of the lower cathode film thickness) is less than the minimum value of the corresponding quality process control range of the upper cathode film thickness (the lower cathode film thickness) or greater than the maximum value of the corresponding quality process control range of the upper cathode film thickness (the lower cathode film thickness), the control end determines that the film thickness of the transparent conductive film of the battery currently prepared exceeds the corresponding quality process control range.

[0064] S4, if the control end determines that the sheet resistance of the battery currently prepared and / or the film thickness of the transparent conductive film exceeds the respective corresponding quality process control range, the oxygen flow of the transparent conductive film deposition device is corrected to adjust the sheet resistance of the subsequent battery deposited, and / or the output power of the transparent conductive film deposition device is corrected to adjust the film thickness of the subsequent transparent conductive film deposited.

[0065] Wherein, since the battery sheet square resistance is related to the oxygen flow of the transparent conductive film deposition equipment and has a corresponding relationship, the embodiment of the present application adjusts the battery sheet square resistance by correcting the oxygen flow of the transparent conductive film deposition equipment; since the film thickness of the transparent conductive film is related to the output power of the transparent conductive film deposition equipment and has a corresponding relationship, the embodiment of the present application adjusts the film thickness of the transparent conductive film by correcting the output power of the transparent conductive film deposition equipment. The embodiment of the present application does not make a detailed description of the corresponding relationship between the battery sheet square resistance and the oxygen flow of the transparent conductive film deposition equipment, and the corresponding relationship between the film thickness of the transparent conductive film and the output power of the transparent conductive film deposition equipment.

[0066] Specifically, if the control terminal determines that the square resistance of the currently prepared battery sheet exceeds the corresponding quality process control range, the oxygen flow of the transparent conductive film deposition equipment is corrected. If the control terminal determines that the film thickness of the transparent conductive film of the currently prepared battery sheet exceeds the corresponding quality process control range, the output power of the transparent conductive film deposition equipment is corrected. If the control terminal determines that the square resistance of the currently prepared battery sheet exceeds the corresponding quality process control range, and the film thickness of the transparent conductive film of the currently prepared battery sheet exceeds the corresponding quality process control range, the oxygen flow of the transparent conductive film deposition equipment and the output power of the transparent conductive film deposition equipment are simultaneously corrected.

[0067] Optionally, the step of correcting the oxygen flow of the transparent conductive film deposition equipment to adjust the square resistance of the subsequent battery sheet in S4 can include the following steps:

[0068] S4-1, the oxygen flow of the upper cathode of the transparent conductive film deposition equipment is corrected according to the difference between the actual square resistance of the upper cathode and the target square resistance of the upper cathode to adjust the square resistance of the upper cathode of the subsequent battery sheet.

[0069] Wherein, the actual square resistance of the upper cathode is the average value of the upper cathode square resistance detected by the detection platform, and the target square resistance of the upper cathode is the ideal square resistance of the upper cathode.

[0070] Optionally, when the oxygen flow of the transparent conductive film deposition equipment is corrected according to the difference between the actual square resistance of the upper cathode and the target square resistance of the upper cathode, the resistance value of the target square resistance of the upper cathode is set as X1, and the resistance value of the actual square resistance of the upper cathode is set as X2, then the difference between the actual square resistance of the upper cathode and the target square resistance of the upper cathode is ΔX=X2-X1, and the oxygen flow of the upper cathode is set as O 2-up Therefore, when the oxygen flow of the upper cathode is corrected, the following cases are included:

[0071] A, when -5≤ΔX≤5, the oxygen flow O 2-up of the upper cathode is unchanged;

[0072] B, when -20≤ΔX<-5 or 5<ΔX≤20, the oxygen flow rate is adjusted according to the formula ΔO = ±(0.1-0.3) x (ΔX / 5); wherein (ΔX / 5) represents the positive integer part of ΔX / 5; when ΔX<0, ±(0.1-0.3) takes the + sign, indicating that the oxygen flow rate of the upper cathode needs to be increased; when ΔX>0, ±(0.1-0.3) takes the - sign, indicating that the oxygen flow rate of the upper cathode needs to be decreased; 2-up 2-down = ±(0.1-0.3) x (ΔX / 5); wherein (ΔX / 5) represents the positive integer part of ΔX / 5; when ΔX<0, ±(0.1-0.3) takes the + sign, indicating that the oxygen flow rate of the upper cathode needs to be increased; when ΔX>0, ±(0.1-0.3) takes the - sign, indicating that the oxygen flow rate of the upper cathode needs to be decreased;

[0073] C, when ΔX<-20 or ΔX>20, the control terminal determines that the error is out of range, and an alarm is prompted.

[0074] The above content is obtained under the assumption that the quality process control requirement -5≤ΔX≤5 is the control line, and -20≤ΔX<-5 or 5<ΔX≤20 is the specification line. The numerical values of the specific control line and the specification line can be set according to needs, and the present embodiment does not make specific limitations thereon.

[0075] S4-2, the oxygen flow rate of the lower cathode of the transparent conductive thin film deposition equipment is corrected according to the difference between the actual square resistance of the lower cathode and the target square resistance of the lower cathode to adjust the square resistance of the lower cathode of the subsequent cell sheet after deposition.

[0076] The actual square resistance of the lower cathode is the average value of the square resistance of the lower cathode detected by the detection platform, and the target square resistance of the lower cathode is the ideal square resistance of the lower cathode.

[0077] Optionally, when the oxygen flow rate of the lower cathode of the transparent conductive thin film deposition equipment is corrected according to the difference between the actual square resistance of the lower cathode and the target square resistance of the lower cathode, the resistance value of the target square resistance of the lower cathode is set as Y1, the resistance value of the actual square resistance of the lower cathode is set as Y2, then the difference between the actual square resistance of the lower cathode and the target square resistance of the lower cathode is ΔY=Y2-Y1, and the oxygen flow rate of the lower cathode is set as O 2-down , then when the oxygen flow rate of the lower cathode is corrected, the following cases are included:

[0078] A, when -5≤ΔY≤5, the oxygen flow rate O 2-down of the lower cathode remains unchanged;

[0079] B, when -20≤ΔY<-5 or 5<ΔY≤20, the oxygen flow rate is adjusted according to the formula ΔO = ±(0.1-0.3) x (ΔY / 5); wherein (ΔY / 5) represents the positive integer part of ΔY / 5; when ΔY<0, ±(0.1-0.3) takes the + sign, indicating that the oxygen flow rate of the lower cathode needs to be increased; when ΔY>0, ±(0.1-0.3) takes the - sign, indicating that the oxygen flow rate of the lower cathode needs to be decreased; 2-down

[0080] C. When ΔY < -20 or ΔY > 20, the control end determines that the error exceeds the range, and an alarm is prompted.

[0081] Optionally, the step of adjusting the film thickness of the subsequent transparent conductive film by correcting the output power of the transparent conductive film deposition device in S4 can comprise the following steps:

[0082] S4.1. Adjusting the upper cathode film thickness of the subsequent transparent conductive film by correcting the output power of the upper cathode of the transparent conductive film deposition device according to the difference between the actual upper cathode film thickness and the target upper cathode film thickness.

[0083] The actual upper cathode film thickness is the average value of the upper cathode film thickness detected by the detection platform, and the target upper cathode film thickness is the ideal upper cathode film thickness.

[0084] Optionally, when the output power of the upper cathode of the transparent conductive film deposition device is corrected according to the difference between the actual upper cathode film thickness and the target upper cathode film thickness in S4.1, the size of the target upper cathode film thickness is set to T up-1 , the size of the actual upper cathode film thickness is T up-2 , and the difference between the actual upper cathode film thickness and the target upper cathode film thickness is ΔT up = T up-2 -T up-1 , the current output power of the upper cathode is set to P up1 , the corrected output power of the upper cathode is set to P up2 , and when the output power of the upper cathode is corrected, the following cases are included:

[0085] a. When -3 ≤ ΔT up ≤ 3, the corrected output power P up2 of the upper cathode remains unchanged;

[0086] b. When -15 ≤ ΔT up < -3 or 3 < ΔT up ≤ 15, the output power of the upper cathode is corrected according to the formula P up2 = ± P up1 × (T up-1 / T up-2 ); wherein, when ΔT up < 0, P up2 takes the plus sign, indicating that the output power of the upper cathode needs to be increased; when ΔT up > 0, P up2 takes the minus sign, indicating that the output power of the upper cathode needs to be reduced;

[0087] c. When ΔT up < -15 or ΔT up > 15, the control end determines that the error exceeds the range, and an alarm is prompted.

[0088] wherein the above content is obtained under the control of the requirement -3≤ΔT up ≤3 as a control line, -15≤ΔT up <-3 or 3<ΔT up ≤15 as a specification line. The numerical values of the control line and the specification line can be set as needed, and the present embodiment does not specifically limit them.

[0089] S4.2, adjusting the lower cathode film thickness of the subsequently deposited transparent conductive film by correcting the output power of the lower cathode of the transparent conductive film deposition device according to the difference between the actual lower cathode film thickness and the target lower cathode film thickness.

[0090] wherein the actual lower cathode film thickness is the average value of the lower cathode film thickness detected by the detection platform, and the target lower cathode film thickness is the ideal lower cathode film thickness.

[0091] Optionally, when correcting the output power of the lower cathode of the transparent conductive film deposition device according to the difference between the actual lower cathode film thickness and the target lower cathode film thickness, the size of the target lower cathode film thickness is set as T down-1 , the size of the actual lower cathode film thickness is set as T down-2 , and the difference between the actual lower cathode film thickness and the target lower cathode film thickness is ΔT down =T down-2 -T down-1 , the current output power of the lower cathode is set as P down1 , and the corrected output power of the lower cathode is set as P down2 , then when correcting the output power of the lower cathode, the following cases are included:

[0092] a, when -3≤ΔT down ≤3, the corrected output power P down2 of the lower cathode remains unchanged;

[0093] b, when -15≤ΔT down <-3 or 3<ΔT down ≤15, the output power of the lower cathode is corrected according to the formula P down2 =±P down1 ×(T down-1 / T down-2 ); wherein when ΔT down <0, P down2 takes the + sign, indicating that the output power of the lower cathode needs to be increased; when ΔT down >0, P down2 takes the - sign, indicating that the output power of the lower cathode needs to be reduced;

[0094] c, when ΔT down <-15 or ΔTdown When the error exceeds the range, the control terminal determines that an alarm is needed.

[0095] S5, the control terminal sends the corrected oxygen flow and / or output power to the transparent conductive film deposition equipment.

[0096] S6, the transparent conductive film deposition equipment deposits a transparent conductive film on a silicon wafer transported subsequently according to the corrected oxygen flow and / or corrected output power.

[0097] Further, in order to determine whether the sheet resistance of the prepared battery and the film thickness of the transparent conductive film exceed the respective corresponding quality process control ranges when the transparent conductive film deposition equipment deposits the transparent conductive film at the current oxygen flow and output power, the method provided by the embodiment of the present application further comprises the following steps after the step S6:

[0098] S7, the sheet resistance of the silicon wafer transported subsequently and the film thickness of the transparent conductive film deposited according to the corrected oxygen flow and / or corrected output power are sampled, and it is determined again whether the sheet resistance of the sampled silicon wafer and / or the film thickness of the transparent conductive film exceed the respective corresponding quality process control ranges, and it is determined according to the determination result whether the oxygen flow and output power need to be corrected. The sampling method, determination method and correction method are the same as those of the above embodiment, and thus will not be described in detail.

[0099] In order to facilitate the understanding of the method provided by the embodiment of the present application, two examples of preparing heterojunction cells and one comparative example are listed as follows:

[0100] Example 1:

[0101] The example comprises the following steps:

[0102] I. The N-type monocrystalline silicon wafer is subjected to texturing treatment to form a pyramid texturing surface, impurity particles are removed and the surface is cleaned to obtain a crystalline silicon substrate;

[0103] II. A first intrinsic amorphous silicon layer and an N-layer doped layer are sequentially deposited on the upper surface of the crystalline silicon substrate by ionized chemical vapor deposition or catalytic chemical vapor deposition, wherein the thickness of the first intrinsic amorphous silicon layer is controlled to be 10 nm and the thickness of the N-type doped layer is controlled to be 20 nm; a second intrinsic amorphous silicon layer and a P-layer doped layer are sequentially deposited on the lower surface of the crystalline silicon substrate by ionized chemical vapor deposition or catalytic chemical vapor deposition, wherein the thickness of the second intrinsic amorphous silicon layer is controlled to be 10 nm and the thickness of the P-type doped layer is controlled to be 15 nm;

[0104] III. PVD is used to deposit 100nm thickness of TCO film on the surface of N layer doped layer and P type doped layer, and the sheet resistance of the cell is monitored by adjusting the oxygen flow during the deposition process. Specifically:

[0105] Take the 2600 pieces / hour production capacity of PVD for heterojunction cells as an example.

[0106] Set the size of the oxygen content: the upper cathode oxygen flow O 2-up , the lower cathode oxygen flow O 2-down ;

[0107] Set the size of the target sheet resistance: the resistance value X1 of the upper cathode (P face) target sheet resistance, and the resistance value Y1 of the lower cathode (N face) target sheet resistance;

[0108] Input the actual sheet resistance: the resistance value X2 of the upper cathode (P face) actual sheet resistance, and the resistance value Y2 of the lower cathode (N face) actual sheet resistance;

[0109] The method for adjusting the oxygen flow (unit: sccm) of the upper and lower cathodes is as follows:

[0110] For the upper cathode: when -5≤ΔX≤5, the oxygen flow O 2-up of the upper cathode remains unchanged; -10﹤ΔX≤-5, the oxygen flow O 2-up of the upper cathode is increased by 0.2; -15﹤ΔX≤-10, the oxygen flow O 2-up of the upper cathode is increased by 0.4; -20﹤ΔX≤-15, the oxygen flow O 2-up of the upper cathode is increased by 0.6; -25﹤ΔX≤-20, the oxygen flow O 2-up of the upper cathode is increased by 0.8; 5﹤ΔX≤10, the oxygen flow O 2-up of the upper cathode is decreased by 0.2; 10﹤ΔX≤15, the oxygen flow O 2-up of the upper cathode is decreased by 0.4; 15﹤ΔX≤20, the oxygen flow O 2-up of the upper cathode is decreased by 0.6; 20﹤ΔX≤25, the oxygen flow O 2-up of the upper cathode is decreased by 0.8; when ΔX﹤-20 or ΔX﹥20, an alarm is prompted.

[0111] For the lower cathode: when -10≤ΔY≤10, the oxygen flow O 2-down of the lower cathode remains unchanged; -20﹤ΔY≤-10, the oxygen flow O 2-down of the lower cathode is increased by 0.2; -30﹤ΔY≤-20, the oxygen flow O2 2-down of the lower cathode is increased by 0.4; -40﹤ΔY≤-30, the oxygen flow O 2-down of the lower cathode is increased by 0.6; -50﹤ΔY≤-40, the oxygen flow O2-down Rise 0.8; 10 < ΔY ≤ 20, oxygen flow O of lower cathode 2-down Fall 0.2; 20 < ΔY ≤ 30, oxygen flow O of lower cathode 2-down Fall 0.4; 30 < ΔY ≤ 40, oxygen flow O of lower cathode 2-down Fall 0.6; 50 < ΔY ≤ 50, oxygen flow O of lower cathode 2-down Fall 0.8; when ΔY < -50 or ΔY > 50, prompt alarm.

[0112] Four, form front and back silver metal electrodes by silk screen printing, main grid line number is 9, grid line width is 0.9mm, sub grid line number is 100, grid line width is 40um;

[0113] Five, sinter to form good ohmic contact between metal and silicon, solidification temperature is 200℃;

[0114] Six, test electrical performance of battery.

[0115] Example Two:

[0116] The example two includes the following steps:

[0117] One, perform texturing treatment on N-type monocrystalline silicon wafer to form pyramid texturing, remove impurity particles and clean surface to obtain crystalline silicon substrate;

[0118] Two, sequentially deposit first intrinsic amorphous silicon layer and N-type doped layer on upper surface of crystalline silicon substrate by ionized physical vapor deposition or catalytic chemical vapor deposition, wherein thickness of first intrinsic amorphous silicon layer is controlled at 12nm, thickness of N-type doped layer is controlled at 15nm; sequentially deposit second intrinsic amorphous silicon layer and P-type doped layer on lower surface of crystalline silicon substrate by ionized physical vapor deposition or catalytic chemical vapor deposition, wherein thickness of second intrinsic amorphous silicon layer is controlled at 15nm, thickness of P-type doped layer is controlled at 16nm;

[0119] Three, deposit 105nm thick TCO film on upper surface of N-type doped layer and lower surface of P-type doped layer by PVD, and monitor film thickness of TCO of battery by regulating output power during deposition process. Specifically:

[0120] (1) Set size of output power: including current output power of upper cathode, denoted as P up1 ; current output power of lower cathode, denoted as P down1 .

[0121] (2) Set size of target film thickness: including target film thickness of upper cathode (P surface), denoted as T up-1 ; target film thickness of lower cathode (N surface), denoted as T down-1 ;

[0122] (3), detecting the actual film thickness: including the actual film thickness of the upper cathode (P face), denoted as T up-2 ; the actual film thickness of the lower cathode (N face), denoted as T down-2 ;

[0123] (4), calculating the difference between the detected actual film thickness and the target film thickness, wherein the difference of the upper cathode: ΔT up = T up-2 -T up-1 ; the difference of the lower cathode: ΔT down = T down-2 -T down-1 ;

[0124] (5), adjusting the power: divided into correcting the output power of the upper cathode and the output power of the lower cathode, the corrected ones are denoted as P up2 and P down2 . Assuming that the control requirement -3≤ΔT up ≤3 is the control line, -15≤ΔTup<-3 or 3<ΔTup≤15 is the specification line, then:

[0125] For the upper cathode:

[0126] A, when -3≤ΔT up ≤3, the corrected output power P up2 of the upper cathode is unchanged;

[0127] B, when -15≤ΔT up <-3 or 3<ΔT up ≤15, the size of the output power of the upper cathode is adjusted according to the formula P up2 = ±P up1 ×(T up-1 / T up-2 ), wherein when ΔT up ﹤0, P up2 takes the + sign, the output power of the upper cathode needs to be increased; when ΔT up ﹥0, P up2 takes the - sign, the output power of the upper cathode needs to be reduced;

[0128] C, when ΔT up ﹤-20 or ΔT up ﹥20, the error exceeds the range, prompting an alarm.

[0129] For the lower cathode:

[0130] A, when -3≤ΔT down ≤3, the corrected output power P down2 of the upper cathode is unchanged;

[0131] B, when -15≤ΔT down <-3 or 3<ΔT down ≤15, according to the formula P down2 =±P down1 ×(T down-1 / T down-2 ) to adjust the size of the lower cathode output power, wherein when ΔT down <0, P down2 takes the + sign, the output power of the lower cathode needs to be increased; when ΔT down >0, P down2 takes the - sign, the output power of the lower cathode needs to be reduced;

[0132] C, when ΔT down <-20 or ΔT down >20, the error exceeds the range, prompting an alarm.

[0133] Four, the front and back silver metal electrodes are formed by screen printing, the main grid line number is 9, the grid line width is 0.9mm, the auxiliary grid line number is 100, and the grid line width is 40um;

[0134] Five, sintering forms a good ohmic contact between the metal and the silicon, and the solidification temperature is 200℃;

[0135] Six, test the electrical performance of the battery.

[0136] Comparative example:

[0137] One, the N-type single crystal silicon wafer is subjected to texturing treatment to form a pyramid textured surface, impurity particles are removed, and the surface is cleaned to obtain a crystalline silicon substrate;

[0138] Two, a first intrinsic amorphous silicon layer and an N-doped layer are sequentially deposited on the upper surface of the crystalline silicon substrate by plasma chemical vapor deposition, wherein the thickness of the first intrinsic amorphous silicon layer is controlled to be 12nm, and the thickness of the N-doped layer is controlled to be 15nm; a second intrinsic amorphous silicon layer and a P-doped layer are sequentially deposited on the lower surface of the crystalline silicon substrate by plasma chemical vapor deposition or catalytic chemical vapor deposition, wherein the thickness of the second intrinsic amorphous silicon layer is controlled to be 15nm, and the thickness of the P-doped layer is controlled to be 16nm;

[0139] Three, a 105nm thick TCO film is deposited on the upper surface of the N-doped layer and the lower surface of the P-doped layer by PVD, and the film thickness and sheet resistance of the battery TCO are monitored by adjusting the power during the deposition process.

[0140] Specifically:

[0141] (1), in the continuous production state, the sheet resistance and film thickness need to be monitored manually every 30 minutes;

[0142] (2), considering the difference and stability of sheet resistance and film thickness, it is necessary to draw samples to different positions of the carrier plate;

[0143] (3), after the sheet resistance and film thickness exceed the control line, the skilled technicians rely on experience to adjust the process parameters, such as oxygen flow and output power, to realize the stability of sheet resistance and film thickness, and the artificial adjustment is time-consuming and laborious, and the result is not accurate enough;

[0144] Four, the front and back silver metal electrodes are formed by screen printing, the main grid line number is 9, the grid line width is 0.9mm, the auxiliary grid line number is 100, and the grid line width is 40um;

[0145] Five, sintering forms a good ohmic contact between the metal and the silicon, and the solidification temperature is 200℃;

[0146] Six, test the electrical performance of the battery.

[0147] Through the above two examples and comparative examples, it can be seen that the method provided by the embodiment of the present application can realize intelligent monitoring of sheet resistance and film thickness, so that the size of sheet resistance and film thickness always remains within the SPC range. Taking the PVD production of 5200 pieces / hour capacity, 12 hours of production as an example, if the sheet resistance of 6 hours is not within the set SPC range, 31200 pieces of defective pieces will enter the screen printing, causing huge waste of manpower and financial resources, and the printed battery piece has low photoelectric conversion efficiency; if the sheet resistance is monitored to be abnormal at the 6th hour, the PVD needs to be stopped to adjust different process parameters to find the best sheet resistance and film thickness, which seriously affects the production capacity. In addition, the method provided by the embodiment of the present application can eliminate the problem of large human error and difficult to control by experience.

[0148] In summary, the method provided by the embodiment of the present application solves the stability problem of sheet resistance and film thickness in the process of depositing a transparent conductive thin film, realizes the regulation and control of sheet resistance and film thickness within the quality control standard specification line, saves the human daily regulation and control, saves manpower, reduces labor cost, avoids the need for technicians to rely on experience to correct parameters after exceeding the quality control range, and improves the accuracy of regulation and control.

[0149] The above only describes the preferred embodiments of the present application and is not used to limit the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be regarded as the protection scope of the present application.

Claims

1. A method for intelligent regulation of sheet resistance and film thickness of a heterojunction cell by TCO device, characterized in that, The method comprises the following steps: S1, placing the silicon wafer with transparent conductive film prepared by the transparent conductive film deposition equipment on a carrier plate and transporting the silicon wafer to a detection platform; S2, detecting the sheet resistance of the silicon wafer and the film thickness of the transparent conductive film by the detection platform, and sending the detection results to a control end of the transparent conductive film deposition equipment; S3, judging whether the sheet resistance of the battery and / or the film thickness of the transparent conductive film prepared by the transparent conductive film deposition equipment currently exceeds the corresponding quality process control range according to the detection results; S4, if the control end determines that the sheet resistance of the battery and / or the film thickness of the transparent conductive film prepared currently exceeds the corresponding quality process control range, adjusting the oxygen flow of the transparent conductive film deposition equipment to adjust the sheet resistance of the subsequent battery, and / or adjusting the output power of the transparent conductive film deposition equipment to adjust the film thickness of the subsequent transparent conductive film; S5, sending the adjusted oxygen flow and / or output power to the transparent conductive film deposition equipment by the control end; S6, depositing the transparent conductive film of the subsequent silicon wafer transported by the transparent conductive film deposition equipment according to the adjusted oxygen flow and / or output power; The step of adjusting the oxygen flow of the transparent conductive film deposition equipment to adjust the sheet resistance of the subsequent battery in S4 comprises the following steps: S4-1, adjusting the oxygen flow of the upper cathode of the transparent conductive film deposition equipment to adjust the sheet resistance of the upper cathode of the subsequent battery according to the difference between the actual sheet resistance of the upper cathode and the target sheet resistance of the upper cathode; The S4-1 corrects the oxygen flow of the upper cathode of the transparent conductive thin film deposition equipment according to the difference between the actual sheet resistance of the upper cathode and the target sheet resistance of the upper cathode, sets the resistance value of the target sheet resistance of the upper cathode as X1, the resistance value of the actual sheet resistance of the upper cathode as X2, and the difference between the actual sheet resistance of the upper cathode and the target sheet resistance of the upper cathode as ΔX=X2-X1, and sets the oxygen flow of the upper cathode as O 2-up Therefore, when correcting the oxygen flow of the upper cathode, the following cases are included: A, when -5 < ΔX < 5, the oxygen flow O of the upper cathode 2-up unchanged; B. When -20≤ΔX<-5 or 5<ΔX≤20, the oxygen flow rate is adjusted according to the formula ΔO = ±(0.1-0.3)×(ΔX / 5), wherein (ΔX / 5) represents the positive integer part of ΔX / 5; when ΔX<0, ±(0.1-0.3) takes the "+" sign, indicating that the oxygen flow rate of the upper cathode needs to be increased; when ΔX>0, ±(0.1-0.3) takes the "-" sign, indicating that the oxygen flow rate of the upper cathode needs to be reduced. 2-up B. When -20≤ΔX<-5 or 5<ΔX≤20, the oxygen flow rate is adjusted according to the formula ΔO = ±(0.1-0.3)×(ΔX / 5), wherein (ΔX / 5) represents the positive integer part of ΔX / 5; when ΔX<0, ±(0.1-0.3) takes the "+" sign, indicating that the oxygen flow rate of the upper cathode needs to be increased; when ΔX>0, ±(0.1-0.3) takes the "-" sign, indicating that the oxygen flow rate of the upper cathode needs to be reduced. S4-2, adjusting the oxygen flow of the lower cathode of the transparent conductive film deposition equipment to adjust the sheet resistance of the lower cathode of the subsequent battery according to the difference between the actual sheet resistance of the lower cathode and the target sheet resistance of the lower cathode; 2. The method of claim 1, wherein, C, when ΔX<-20 or ΔX>20, the control end determines that the error exceeds the range, and an alarm is prompted. The step of adjusting the output power of the transparent conductive film deposition equipment to adjust the film thickness of the subsequent transparent conductive film in S4 comprises the following steps: S4.1, adjusting the output power of the upper cathode of the transparent conductive film deposition equipment to adjust the film thickness of the upper cathode of the subsequent transparent conductive film according to the difference between the actual film thickness of the upper cathode and the target film thickness of the upper cathode; 3. The method of claim 2, wherein, The S4.1 sets the size of the target film thickness of the upper cathode as T up-1 The size of the actual film thickness of the upper cathode is T up-2 The difference between the actual film thickness of the upper cathode and the target film thickness of the upper cathode is ΔT up = T up-2 - T up-1 The current output power of the upper cathode is set as P up1 The corrected output power of the upper cathode is set as P up2 When the output power of the upper cathode is corrected, the following cases are included: a. When -3 < ΔT < 3, the output power P up of the upper cathode after correction is unchanged. up2 ; b. when -15≤ΔT up < -3 or 3 < ΔT up ≤ 15, the output power of the upper cathode is corrected according to the formula P up2 = ±P up1 × (T up-1 / T up-2 ); wherein when ΔT up < 0, P up2 takes the + sign, indicating that the output power of the upper cathode needs to be increased; when ΔT up > 0, P up2 takes the - sign, indicating that the output power of the upper cathode needs to be reduced; c、 when ΔT up ﹤-15 or ΔT up ﹥15, the control end determines that the error exceeds the range, and an alarm prompt is given.

4. The method of claim 1, wherein, S4.2, adjusting the output power of the lower cathode of the transparent conductive film deposition equipment to adjust the film thickness of the lower cathode of the subsequent transparent conductive film according to the difference between the actual film thickness of the lower cathode and the target film thickness of the lower cathode. After the step of depositing the transparent conductive film of the subsequent silicon wafer transported by the transparent conductive film deposition equipment according to the adjusted oxygen flow and / or output power in S6, the method further comprises:

5. The method of claim 1, wherein, S7, detecting the sheet resistance of the silicon wafer and the film thickness of the transparent conductive film according to the adjusted oxygen flow and / or output power, and judging again whether the sheet resistance of the silicon wafer and / or the film thickness of the transparent conductive film exceeds the corresponding quality process control range. The step of detecting the sheet resistance of the silicon wafer and the film thickness of the transparent conductive film by the detection platform in S2 comprises the following steps: S21, selecting several representative battery wafers on the carrier plate as the silicon wafer to be detected by the detection platform; S22, the detection platform detects the square resistance of each representative silicon wafer to be detected, calculates the average square resistance of each silicon wafer to be detected, and takes the average square resistance as the square resistance detection result; S23, the detection platform detects the transparent conductive film thickness of each representative silicon wafer to be detected, calculates the average of each transparent conductive film thickness, and takes the average of the transparent conductive film thickness as the film thickness detection result.

6. The method of claim 5, wherein, The representative several battery pieces on the carrier plate include the battery pieces at the two edges and the middle of the first row, the battery pieces at the edges and the middle of the last row, and the battery pieces at the two edges and the middle of the middle row of the carrier plate.

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