CN-117096225-B - Method for reducing damage of copper plating to performance of solar heterojunction battery through PVD (physical vapor deposition) deposition

CN117096225BCN 117096225 BCN117096225 BCN 117096225BCN-117096225-B

Abstract

The invention discloses a method for reducing damage of copper plating to a battery piece by PVD (physical vapor deposition) deposition of a solar heterojunction battery, which comprises the following steps of double-sided texturing on an N-type silicon wafer of a substrate, and respectively depositing amorphous silicon layers on the front side and the back side of the silicon wafer; the method comprises the steps of respectively depositing transparent TCO conductive films on the front side and the back side of a silicon wafer plated with an amorphous silicon layer by a magnetron sputtering method, respectively depositing copper metal film layers on the transparent conductive film layers on the front side and the back side of the silicon wafer, wherein the copper metal film layers consist of a plurality of film layers with different thicknesses and are sequentially formed from thin to thick, the thickness of the film layer close to the TCO conductive film is the thinnest, forming metal grid line electrodes on the copper metal film layers on the front side and the back side of the N-type silicon wafer, and removing the copper metal film layers outside a metal grid line electrode area. The method can reduce the damage to ITO and amorphous silicon when PVD deposits copper in the metallization process of the heterojunction battery, and improve the photoelectric performance of the film.

Inventors

GUO HAILONG
ZENG QINGHUA
WANG YUHUA

Assignees

福建金石能源有限公司

Dates

Publication Date: 20260512
Application Date: 20220513

Claims (5)

1. A method for reducing damage of copper plating to cell performance by PVD (physical vapor deposition) deposition of a solar heterojunction cell is characterized by comprising the following steps: double-sided texturing is carried out on the N-type silicon wafer of the substrate, and amorphous silicon layers are respectively deposited on the front side and the back side of the silicon wafer; Respectively depositing transparent TCO conductive films on the front and back sides of the silicon wafer plated with the amorphous silicon layer by adopting a magnetron sputtering method; Respectively depositing copper metal film layers on transparent conductive film layers on the front side and the back side of the silicon wafer, wherein the copper metal film layers consist of a plurality of film layers with different thicknesses and are sequentially displayed from thin to thick, and the thickness of the film layer close to the TCO conductive film is the thinnest; The power density of the copper metal film layer is 1-1.5w/mm near the first layer target copper of the TCO conductive film, the power density of the copper of the second layer target copper is 3-3.7w/mm, the power density of the copper of the third layer target copper is 5-5.5w/mm, the power density of the copper of the fourth layer target copper is 6-6.5w/mm, the thickness of the copper metal film layer near the first layer target copper of the TCO conductive film is 100-150A, the thickness of the copper of the second layer target copper is 300-350A, the thickness of the copper of the third layer target copper is 400-450A, and the thickness of the copper of the fourth layer target copper is 500-600A; Forming metal grid line electrodes on the copper metal film layers on the front surface and the back surface of the N-type silicon wafer; and removing the copper metal film layer outside the metal grid line electrode area.
2. The method for reducing damage to cell performance by copper plating of solar heterojunction cell PVD according to claim 1, wherein the TCO conductive film material comprises indium oxide and tin oxide in a ratio of 95% to 5% or 90% to 10%.
3. The method for reducing damage of copper plating on cell performance by PVD (physical vapor deposition) of a solar heterojunction cell according to claim 1 is characterized in that the thickness of the transparent TCO conductive film deposited on the front side and the back side is 100-120 nm.
4. The method for reducing damage of copper plating on cell performance by PVD deposition of a solar heterojunction cell as claimed in claim 1, wherein the chamber pressure of the copper metal film deposition target is controlled within 0.3-0.5 Pa.
5. The method for reducing damage of copper plating on cell performance by PVD deposition of solar heterojunction cells according to claim 1, wherein the method for forming metal gate line electrode is to cover front and back surfaces of copper metal film layer with photosensitive film, exposing seed layer copper to ultraviolet light to form gate line electrode pattern, and developing the gate line electrode pattern with developer.

Description

Method for reducing damage of copper plating to performance of solar heterojunction battery through PVD (physical vapor deposition) deposition Technical Field The invention relates to the field of solar cells, in particular to a method for reducing performance damage of copper plating on a cell by PVD (physical vapor deposition) deposition of a solar heterojunction cell. Background The sustainable development of energy and environment has become a hot point of global concern, and photovoltaic power generation has the advantage that the traditional energy is incomparable, so that the direct conversion of solar energy into electric energy is realized, and the solar energy is the most ideal green energy with sustainable development. How to fully utilize solar energy, improve the photoelectric conversion efficiency of the solar cell and reduce the electricity cost of the solar cell has become the ultimate goal of the scientific researchers struggling. In the process of the technical innovation of the high-efficiency solar battery, the heterojunction battery is praised as a high-efficiency N-type battery which is most likely to realize large-scale industrial application in the future, and the heterojunction battery is expected to realize low-price internet surfing before and after 2020. However, the high cost of the traditional Chinese medicine composition also enables a plurality of enterprises to be in a sightseeing situation. How to reduce the manufacturing cost of solar cells while ensuring high efficiency has become the subject of intensive research by the industry research institutions and enterprises. In the process of preparing the heterojunction battery, the battery metallization process is one of key steps for determining the battery efficiency and the battery cost, and the metal electrode has high bonding strength and low contact resistance with a silicon interface and also provides a high conduction path for current output. At present, most of commercial crystalline silicon battery metal electrodes are prepared by adopting a screen printing technology, however, whether the screen printing technology can meet the market demands of high-efficiency and low-cost development of heterojunction batteries in the future is questioned. Exploration of metallization technology matched with heterojunction cells is one of the effective ways to reduce cell cost and improve cell photoelectric conversion efficiency. The japanese Kaneka company announced that the efficiency of double-sided hetero-crystalline silicon solar cells using copper contact metallization recorded up to 25.1%, was validated by the germany schoenhou solar systems institute (FraunhoferISE), and was planning to build a test line using this technique. The electrolytic copper plating technology has the advantages of simple device, low production cost, uniform and compact plating layer, good conductivity and the like. In the preparation process of the battery electrode, the width and the height of the grid line are controllable, the height-width ratio of the grid line can be effectively improved, the shadow loss blocked by the grid line is reduced, meanwhile, the contact resistance between the electrode and the PN junction, the body resistance of the electrode and the series resistance of the battery are effectively reduced, and the photoelectric conversion efficiency of the battery is improved. Disclosure of Invention Aiming at the problems, the invention provides a method for reducing the damage of copper plating to the performance of a cell by PVD (physical vapor deposition) deposition of a solar heterojunction cell, so as to rapidly improve the damage of deposited copper to amorphous silicon and TCO (transparent conducting oxide), thereby improving the photoelectric performance of a film. In order to solve the technical problems, the technical scheme adopted by the invention is that the method for reducing the damage of copper plating to the performance of the battery piece by PVD deposition of the solar heterojunction battery comprises the following steps: double-sided texturing is carried out on the N-type silicon wafer of the substrate, and amorphous silicon layers are respectively deposited on the front side and the back side of the silicon wafer; Respectively depositing transparent TCO conductive films on the front and back sides of the silicon wafer plated with the amorphous silicon layer by adopting a magnetron sputtering method; Respectively depositing copper metal film layers on transparent conductive film layers on the front side and the back side of the silicon wafer, wherein the copper metal film layers consist of a plurality of film layers with different thicknesses and are sequentially displayed from thin to thick, and the thickness of the film layer close to the TCO conductive film is the thinnest; Forming metal grid line electrodes on the copper metal film layers on the front surface and the back surface of the N-type silicon wafe