CN116682895A - Method for improving diffusion coating during electroplating of solar cell - Google Patents

Method for improving diffusion coating during electroplating of solar cell Download PDF

Info

Publication number
CN116682895A
CN116682895A CN202310596175.2A CN202310596175A CN116682895A CN 116682895 A CN116682895 A CN 116682895A CN 202310596175 A CN202310596175 A CN 202310596175A CN 116682895 A CN116682895 A CN 116682895A
Authority
CN
China
Prior art keywords
copper
layer
solar cell
copper seed
plating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310596175.2A
Other languages
Chinese (zh)
Inventor
朱万宇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tongwei Solar Chengdu Co Ltd
Original Assignee
Tongwei Solar Chengdu Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tongwei Solar Chengdu Co Ltd filed Critical Tongwei Solar Chengdu Co Ltd
Priority to CN202310596175.2A priority Critical patent/CN116682895A/en
Publication of CN116682895A publication Critical patent/CN116682895A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/02—Electroplating of selected surface areas
    • C25D5/022—Electroplating of selected surface areas using masking means
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/12—Semiconductors
    • C25D7/123—Semiconductors first coated with a seed layer or a conductive layer
    • C25D7/126—Semiconductors first coated with a seed layer or a conductive layer for solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H01L31/022433—Particular geometry of the grid contacts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/20—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials
    • H01L31/202—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials including only elements of Group IV of the Periodic Table
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Materials Engineering (AREA)
  • Sustainable Development (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Energy (AREA)
  • Photovoltaic Devices (AREA)

Abstract

The invention provides a method for improving the diffusion coating of a solar cell during electroplating, which comprises the following steps: providing a solar cell precursor, wherein a copper seed layer is arranged on the solar cell precursor, and a copper oxide layer is arranged on the surface of the copper seed layer; removing the copper oxide layer; preparing a photoresist layer on the copper seed layer after the copper oxide layer is removed; sequentially exposing and developing the photoresist layer to obtain a patterned photoresist layer, wherein the patterned photoresist layer is provided with a slot, part of the copper seed layer is exposed to the slot, the copper seed layer exposed to the slot is defined as a first copper seed part, and the copper seed layer not exposed to the slot is defined as a second copper seed part; electroplating copper on the first copper seed part to obtain a copper grid line; and removing the patterned photoresist layer and the second copper seed portion. The invention can improve the conversion efficiency and the appearance of the solar cell.

Description

Method for improving diffusion coating during electroplating of solar cell
Technical Field
The invention relates to the technical field of solar cells, in particular to a method for improving the diffusion coating of a solar cell during electroplating.
Background
In the process of preparing a solar cell, it is generally required to prepare a photoresist layer on a copper seed layer of a solar cell precursor, further form a patterned photoresist layer on the photoresist layer, and then electroplate the patterned photoresist layer to prepare a copper gate line on the copper seed layer, and finally remove the copper seed layer not covered by the copper gate line.
However, in performing electroplating, a problem of the diffusion plating often occurs. Wherein, the percolation plating refers to that the width of the copper grid line prepared during copper electroplating is larger than a set value due to the rising, missing or existence of holes between the patterned photoresist layer and the copper seed layer. This directly increases the light-shielding area of the subsequently prepared solar cell and reduces the light-absorbing area, thereby affecting the conversion efficiency of the solar cell and also affecting the appearance of the solar cell.
Disclosure of Invention
Based on this, it is necessary to provide a method for improving the diffusion coating of solar cells during electroplating to increase the conversion efficiency and appearance of subsequently fabricated solar cells.
The invention provides a method for improving the diffusion coating of a solar cell during electroplating, which comprises the following steps:
providing a solar cell precursor, wherein a copper seed layer is arranged on the solar cell precursor, and a copper oxide layer is arranged on the surface of the copper seed layer;
removing the copper oxide layer;
preparing a photoresist layer on the copper seed layer after the copper oxide layer is removed;
sequentially exposing and developing the photoresist layer to obtain a patterned photoresist layer, wherein the patterned photoresist layer is provided with a slot, part of the copper seed layer is exposed to the slot, the copper seed layer exposed to the slot is defined as a first copper seed part, and the copper seed layer not exposed to the slot is defined as a second copper seed part;
electroplating copper on the first copper seed part to obtain a copper grid line; and
and removing the patterned photoresist layer and the second copper seed part.
In some of these embodiments, after removing the copper oxide layer, and before preparing the photoresist layer, the method further comprises the steps of:
forming a protective layer on the copper seed layer after the copper oxide layer is removed;
wherein the protective layer is removed at the time of the copper plating.
In some of these embodiments, forming a protective layer on the copper seed layer after removing the copper oxide layer includes the steps of:
reacting at least one of phenylbenzimidazole, alkylbenzimidazole, and alkylimidazole with the copper seed layer after removing the copper oxide layer to form the protective layer.
In some of these embodiments, the protective layer is an organic protective layer, including an organic solderability protective layer.
In some of these embodiments, the method further comprises a step of water washing after removing the copper oxide layer and before forming the protective layer.
In some of these embodiments, after forming the protective layer, and before preparing the photoresist layer, the method further comprises the steps of washing with water and drying.
In some of these embodiments, removing the copper oxide layer comprises the steps of:
the copper oxide layer is removed using an acidic solution.
In some of these embodiments, the acidic solution comprises sulfuric acid.
In some of these embodiments, in the step of electroplating copper, the copper plating solution includes a copper sulfate solution, and the dropping time of the copper plating solution is 3s to 6s.
In some of these embodiments, after the copper gate lines are obtained, and before the patterned photoresist layer and the second copper seed portions are removed, the method further comprises the steps of:
electroplating tin on the copper grid line by adopting tin electroplating liquid to obtain a tin grid line;
the tin plating solution comprises tin methylsulfonate, and at least one of indium methylsulfonate, lead methylsulfonate and cerium sulfate.
In the conventional technology, when a solar cell is manufactured, a copper seed layer is subjected to the influence of water vapor, oxygen and the like to generate a copper oxide layer, then a patterned photoresist layer is prepared on the copper seed layer with the copper oxide layer, when copper is electroplated later, sulfuric acid is required to be used for pre-soaking, the sulfuric acid is used for carrying out lateral biting on the copper oxide layer very fast, a section of electroplated area is formed below the patterned photoresist layer, namely holes exist between the patterned photoresist layer and the copper seed layer, and the problem of diffusion plating occurs. Before preparing the photoresist layer, the copper oxide layer on the surface of the copper seed layer is removed firstly to expose fresh metal copper, namely the copper seed layer is exposed, so that holes between the patterned photoresist layer and the copper seed layer are avoided, the problem of plating penetration is avoided, the width of the copper grid line prepared during copper electroplating is equal to a set value, and the conversion efficiency and the appearance of a solar cell prepared later are improved.
Drawings
FIG. 1 is a flow chart for improving the electroplating of a solar cell according to the present invention;
FIG. 2 is a cross-sectional view of a solar cell precursor provided by the present invention;
FIG. 3 is a cross-sectional view of the transparent conductive oxide layer of FIG. 2 after a copper seed layer has been prepared thereon;
FIG. 4 is a cross-sectional view of the copper seed layer of FIG. 3 after preparation of a photoresist layer;
FIG. 5 is a cross-sectional view of the photoresist layer of FIG. 4 after exposure and development;
FIG. 6 is a cross-sectional view of the first copper seed of FIG. 5 after copper gate lines have been fabricated thereon;
FIG. 7 is a cross-sectional view of the copper wire of FIG. 6 after the tin wire is formed;
FIG. 8 is a cross-sectional view of the patterned photoresist layer of FIG. 7 after removal;
fig. 9 is a cross-sectional view of the solar cell of fig. 8 after removal of the second copper seed portion;
FIG. 10 is a metallographic microscope image of a copper interconnect solar cell prepared in example 1 of the present invention;
fig. 11 is a metallographic microscope image of a copper-interconnect solar cell prepared in comparative example 1 of the present invention.
Reference numerals: 100-solar cell; 10-a solar cell precursor; 11-a substrate; 12-an amorphous silicon layer; 13-a transparent conductive oxide layer; a 20-copper seed layer; 201-a first copper seed portion; 202-a second copper seed portion; 30-a photoresist layer; 40-patterning the photoresist layer; 41-slotting; 50-copper grid lines; 60-tin grid lines; 70-electrode.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, the present invention provides a method for improving the diffusion coating of a solar cell during electroplating, comprising the following steps:
in step S11, referring to fig. 2, a solar cell precursor 10 is provided.
In one embodiment, the solar cell precursor 10 includes a substrate 11, an amorphous silicon layer 12 and a transparent conductive oxide layer 13 sequentially stacked on the substrate 11. In one embodiment, the substrate 11 may be a silicon wafer. Specifically, the silicon wafer may be a textured silicon wafer.
In an embodiment, the amorphous silicon layer 12 on the upper surface of the substrate 11 and the amorphous silicon layer 12 on the lower surface of the substrate 11 may be different. Specifically, the amorphous silicon layer 12 on the upper surface of the substrate 11 includes an intrinsic amorphous silicon layer and an N-type amorphous silicon layer, and the amorphous silicon layer 12 on the lower surface of the substrate 11 includes an intrinsic amorphous silicon layer and a P-type amorphous silicon layer.
In step S12, please refer to fig. 3, a copper seed layer 20 is prepared on the transparent conductive oxide layer 13.
Specifically, the copper seed layer 20 may be prepared on the transparent conductive oxide layer 13 using a PVD (physical vapor deposition) magnetron sputtering method.
In one embodiment, the thickness of the copper seed layer 20 is 200nm to 300nm.
Wherein the copper seed layer has a copper oxide layer (not shown) on the surface thereof due to the influence of moisture, oxygen, and the like. I.e. part of the copper seed layer is oxidized to the copper oxide layer. That is, a portion of the elemental copper of the copper seed layer is oxidized to copper oxide.
And S13, removing the copper oxide layer.
Specifically, an acidic solution is placed in a pickling tank, and the acidic solution and the copper oxide layer are reacted to remove the copper oxide layer.
In one embodiment, the acidic solution comprises sulfuric acid.
In one embodiment, after removing the copper oxide layer, a water washing step is further included to remove the acidic solution remaining on the solar cell precursor 10 and the copper seed layer 20. Specifically, the washing may be performed in a washing tank.
Step S14, forming a protective layer (not shown) on the copper seed layer 20 after removing the copper oxide layer.
Specifically, a protective solution is placed in a protective tank, and the protective solution is reacted with the copper seed layer 20 after the copper oxide layer is removed to form the protective layer. Wherein the protective layer is capable of insulating air to prevent the copper seed layer 20 from being oxidized again after the copper oxide layer is removed.
In one embodiment, the protective solution contains at least one of phenylbenzimidazole, alkylbenzimidazole, and alkylimidazole. That is, phenylbenzimidazole, alkylbenzimidazole, and alkylimidazole may all react with the copper seed layer 20 after the copper oxide layer is removed to generate the protective layer.
In one embodiment, the alkyl imidazole may be 1-dodecyl imidazole. In one embodiment, the mass fraction of 1-dodecyl imidazole in the protective solution may be 3% to 5%.
In an embodiment, the protective layer may be an organic protective layer. In one embodiment, the organic protective layer comprises an Organic Solderability Preservative (OSP).
In one embodiment, after forming the protective layer, a water washing step is further included to remove the protective solution remaining on the solar cell precursor 10, the copper seed layer 20, and the protective layer. Specifically, the washing may be performed in a washing tank.
In one embodiment, after the washing, a step of drying is further included to dry the solar cell precursor 10, the copper seed layer 20, and the protective layer. Specifically, the drying may be performed in a drying tank.
In step S15, referring to fig. 4, a photoresist layer 30 is prepared on the protective layer.
Specifically, a photoresist solution is coated on the protective layer, and the photoresist layer 30 is obtained after drying.
In one embodiment, the thickness of the photoresist layer 30 is 10 μm to 15 μm.
In an embodiment, after the photoresist layer 30 is prepared, the solar cell precursor 10 after the photoresist layer 30 is prepared may be further coated. Namely, the four edges and the corner positions of the solar cell precursor 10 after the photoresist layer 30 is prepared are wrapped by using edge wrapping adhesive. In one embodiment, the width of the binding glue is less than or equal to 50 μm, and the thickness of the binding glue is 10 μm to 15 μm.
In step S16, referring to fig. 5, the photoresist layer 30 is sequentially exposed and developed to obtain a patterned photoresist layer 40.
The patterned photoresist layer 40 has a slot 41, and a portion of the copper seed layer 20 is exposed to the slot 41.
Wherein the copper seed layer 20 exposed to the trenches 41 is defined as a first copper seed portion 201 and the copper seed layer 20 not exposed to the trenches 41 is defined as a second copper seed portion 202.
In step S17, referring to fig. 6, copper is electroplated on the first copper seed 201 to obtain the copper gate line 50.
Specifically, a copper plating solution is placed in a copper plating bath, and the product obtained in step S16 is placed in the copper plating solution and plated to prepare the copper grid 50 on the first copper seed portion 201 with the copper grid 50 positioned in the groove 41.
Wherein, before the product obtained in step S16 is placed in the copper plating solution, the product obtained in step S16 needs to be pre-soaked with sulfuric acid.
In one embodiment, the copper plating solution comprises a copper sulfate solution.
It will be appreciated that when copper plating is performed in a copper sulfate solution to produce the copper grid 50, copper ions cannot be deposited on the first copper seed portion 201 because the protective layer is still present on the copper seed layer 20 at this time, and it is necessary to break the protective layer by the pinch points of the plating rack, that is, the protective layer can be broken by physical action of external force at the pinch points of the plating rack. Wherein, in the previous stage of the copper electroplating, an electrolytic water reaction mainly occurs, hydrogen is generated at the pinch point, the protective layer near the pinch point is stripped off, and then the protective layer is spread to the periphery until the whole protective layer is stripped off, the first copper seed portion 201 is exposed, the stripping process is generally completed within a period of 5s to 10s, and then copper ions are deposited on the first copper seed portion 201 to form the copper grid line 50.
In one embodiment, in the electrolytic copper plating, the dropping time of the copper plating solution is 3s to 6s. That is, after the copper plating is completed, the product obtained in step S16 needs to be taken out of the copper plating bath, so that the copper plating solution remains on the product obtained in step S16, and in order to reduce the carry-out of the copper plating solution, the product obtained in step S16 needs to be placed above the copper plating bath for 3 to 6 seconds, so that the copper plating solution remaining on the product obtained in step S16 is re-flowed into the copper plating bath. It can be understood that the dripping time is the time for the product prepared in step S16 to stand above the copper plating tank.
The inventor has found through long-term research that when the patterned photoresist layer with the copper plating solution is placed in the air for a long time, the patterned photoresist layer is pulled by the generated surface tension due to volatilization of the copper plating solution, so that the patterned photoresist layer is tilted, and the problem of percolation plating occurs. Therefore, the invention reduces the dripping time from the original 60S to 3S-6S, i.e. the standing time of the product prepared in the step S16 above the copper plating tank is reduced from the original 60S to 3S-6S, and the standing time of the patterned photoresist layer 40 with the copper plating solution in the air is reduced, thereby reducing the tilting of the patterned photoresist layer 40, further avoiding the problem of the occurrence of the percolation plating, and improving the conversion efficiency and the appearance of the solar cell prepared later.
In one embodiment, the thickness of the copper gate line 50 may be 8 μm to 10 μm.
In step S18, referring to fig. 7, tin is electroplated on the copper gate line 50 to obtain a tin gate line 60.
Specifically, a tin plating solution containing tin methylsulfonate is placed in a tin plating bath, and the product obtained in step S17 is placed in the tin plating solution and plated to prepare the tin grid line 60 on the copper grid line 50 with the tin grid line 60 located in the slot 41. Wherein the tin plating solution further contains at least one of indium methylsulfonate, lead methylsulfonate and cerium sulfate.
The tin plating solution used in the traditional tin plating only contains tin methylsulfonate, but because the electrode potential of the tin is-0.136V, hydrogen evolution reaction near a cathode is serious, tiny hydrogen bubbles are generated to attack the bottom of the patterned photoresist layer, and the patterned photoresist layer is tilted, so that the problem of percolation plating occurs. The tin plating solution provided by the invention not only contains tin methylsulfonate, but also contains at least one of indium methylsulfonate, lead methylsulfonate and cerium sulfate, and as the electrode potential of indium is +0.33V, the electrode potential of lead is-0.126V, and the electrode potential of cerium is +1.27V, the co-deposition potential of tin can be improved, and the attack of bubbles generated by hydrogen evolution reaction on the bottom of the patterned photoresist layer 40 is reduced, so that the tilting of the patterned photoresist layer 40 is reduced, the problem of plating seepage is avoided, and the conversion efficiency and the appearance of the subsequently prepared solar cell are improved.
In one embodiment, the thickness of the tin gate line 60 is 2 μm to 4 μm.
In step S19, referring to fig. 8, the patterned photoresist layer 40 is removed by using an alkaline solution.
In one embodiment, the alkaline solution comprises an alkaline agent. In one embodiment, the alkaline agent comprises sodium hydroxide or potassium hydroxide. I.e. the alkaline solution may be a sodium hydroxide solution or a potassium hydroxide solution.
In step S20, referring to fig. 9, the second copper seed 202 is removed by using a etching solution containing an acidic reagent to obtain the electrode 70, thereby obtaining the solar cell 100.
In one embodiment, the acidic reagent in the etching back liquid comprises sulfuric acid. Specifically, the etching back liquid is a dilute sulfuric acid solution.
Wherein the first copper seed 201, the copper gate line 50 and the tin gate line 60 together form the electrode 70.
In one embodiment, after the electrode 70 is obtained, a light injection step may also be performed for repair and efficacy.
In one embodiment, the temperature of the light injection is 200 ℃ to 220 ℃. In one embodiment, the light is injected for a time period of 60s to 120s.
In an embodiment, the solar cell 100 may be a copper interconnect solar cell.
In the conventional technology, when a solar cell is manufactured, a copper seed layer is subjected to the influence of water vapor, oxygen and the like to generate a copper oxide layer, then a patterned photoresist layer is prepared on the copper seed layer with the copper oxide layer, when copper is electroplated later, sulfuric acid is required to be used for pre-soaking, the sulfuric acid is used for carrying out lateral biting on the copper oxide layer very fast, a section of electroplated area is formed below the patterned photoresist layer, namely holes exist between the patterned photoresist layer and the copper seed layer, and the problem of diffusion plating occurs. Before preparing the photoresist layer 30, the copper oxide layer on the surface of the copper seed layer 20 is removed to expose fresh metal copper, i.e. to expose the copper seed layer 20, so as to avoid the existence of holes between the patterned photoresist layer 40 and the copper seed layer 20, and further avoid the problem of plating by diffusion, so that the width of the copper grid line 50 prepared during copper electroplating is equal to a set value, thereby improving the conversion efficiency and appearance of the solar cell 100 prepared later.
The inventor has found through long-term research that when the patterned photoresist layer with the copper plating solution is placed in the air for a long time, the patterned photoresist layer is pulled by the generated surface tension due to volatilization of the copper plating solution, so that the patterned photoresist layer is tilted, and the problem of percolation plating occurs. Therefore, the invention reduces the dripping time from the original 60S to 3S-6S, i.e. the standing time of the product prepared in the step S16 above the copper plating tank is reduced from the original 60S to 3S-6S, thereby reducing the standing time of the patterned photoresist layer 40 with the copper plating solution in the air, reducing the tilting of the patterned photoresist layer 40, and further avoiding the problem of the occurrence of the percolation plating, and improving the conversion efficiency and the appearance of the solar cell 100 prepared later.
The tin plating solution used in the traditional tin plating only contains tin methylsulfonate, but because the electrode potential of the tin is-0.136V, hydrogen evolution reaction near a cathode is serious, tiny hydrogen bubbles are generated to attack the bottom of the patterned photoresist layer, and the patterned photoresist layer is tilted, so that the problem of percolation plating occurs. The tin plating solution provided by the invention not only contains tin methylsulfonate, but also contains at least one of indium methylsulfonate, lead methylsulfonate and cerium sulfate, and as the electrode potential of indium is +0.33V, the electrode potential of lead is-0.126V, and the electrode potential of cerium is +1.27V, the co-deposition potential of tin can be improved, and the attack of bubbles generated by hydrogen evolution reaction on the bottom of the patterned photoresist layer 40 can be reduced, so that the tilting of the patterned photoresist layer 40 is reduced, the problem of plating seepage is avoided, and the conversion efficiency and the appearance of the subsequently prepared solar cell 100 are improved.
The invention is further illustrated by the following specific examples and comparative examples.
Example 1
(1) A solar cell precursor is provided, and the solar cell precursor comprises a substrate, an amorphous silicon layer and a transparent conductive oxide layer which are sequentially laminated on the substrate. The amorphous silicon layer on the upper surface of the substrate comprises an intrinsic amorphous silicon layer and an N-type amorphous silicon layer, and the amorphous silicon layer on the lower surface of the substrate comprises an intrinsic amorphous silicon layer and a P-type amorphous silicon layer.
(2) And preparing a copper seed layer on the transparent conductive oxide layer by adopting a physical vapor deposition magnetron sputtering method. The thickness of the copper seed layer is 200nm, and the surface of the copper seed layer is provided with a copper oxide layer.
(3) And placing the sulfuric acid solution in a pickling tank, reacting sulfuric acid with the copper oxide layer to remove the copper oxide layer, and washing the solar cell precursor after the copper oxide layer is removed with water.
(4) And (3) reacting the copper seed layer on the washed solar cell precursor with a protective solution to form an organic solderability protection layer on the copper seed layer. Wherein the protective solution contains 1-dodecyl imidazole, and the mass fraction of the 1-dodecyl imidazole in the protective solution is 3%.
(5) Coating photoresist solution on the protective layer, and drying to obtain photoresist layer. Wherein the thickness of the photoresist layer is 10 μm.
(6) And (5) wrapping four edges and the corners of the product obtained in the step (5) by using edge wrapping glue. Wherein the width of the binding glue is equal to 50 mu m, and the thickness of the binding glue is 15 mu m.
(7) And sequentially exposing and developing the photoresist layer to obtain the patterned photoresist layer. The patterned photoresist layer is provided with a slot, part of the copper seed layer is exposed to the slot, the copper seed layer exposed to the slot is defined as a first copper seed part, and the copper seed layer not exposed to the slot is defined as a second copper seed part.
(8) Pre-soaking the product obtained in the step (7) by sulfuric acid, then placing copper sulfate in a copper plating tank, placing the pre-soaked product in the copper sulfate, and electroplating to prepare copper grid lines on the first copper seed part, and positioning the copper grid lines in the grooves. After the copper plating is completed, the product obtained after the copper plating is taken out of the copper plating tank and placed above the copper plating tank for 5s. Wherein the organic solderability preservative is removed during electroplating.
(9) Placing a tin electroplating solution containing tin methylsulfonate and indium methylsulfonate in a tin plating tank, and placing the product prepared in the step (8) in the tin electroplating solution for electroplating to prepare tin grid lines on the copper grid lines and enable the tin grid lines to be positioned in the grooves.
(10) The patterned photoresist layer was removed using sodium hydroxide solution.
(11) And removing the second copper seed part by using a dilute sulfuric acid solution to obtain an electrode, thereby obtaining the copper interconnection solar cell.
Comparative example 1
(1) A solar cell precursor is provided, and the solar cell precursor comprises a substrate, an amorphous silicon layer and a transparent conductive oxide layer which are sequentially laminated on the substrate. The amorphous silicon layer on the upper surface of the substrate comprises an intrinsic amorphous silicon layer and an N-type amorphous silicon layer, and the amorphous silicon layer on the lower surface of the substrate comprises an intrinsic amorphous silicon layer and a P-type amorphous silicon layer.
(2) And preparing a copper seed layer on the transparent conductive oxide layer by adopting a physical vapor deposition magnetron sputtering method. The thickness of the copper seed layer is 200nm, and the surface of the copper seed layer is provided with a copper oxide layer.
(3) Coating a photoresist solution on the copper seed layer with the copper oxide layer, and drying to obtain the photoresist layer. Wherein the thickness of the photoresist layer is 10 μm.
(4) And (3) wrapping four edges and corner positions of the product obtained in the step (3) by using edge wrapping glue. Wherein the width of the binding glue is equal to 50 mu m, and the thickness of the binding glue is 15 mu m.
(5) And sequentially exposing and developing the photoresist layer to obtain the patterned photoresist layer. The patterned photoresist layer is provided with a slot, part of the copper seed layer is exposed to the slot, the copper seed layer exposed to the slot is defined as a first copper seed part, and the copper seed layer not exposed to the slot is defined as a second copper seed part.
(6) Pre-soaking the product obtained in the step (5) by sulfuric acid, then placing copper sulfate in a copper plating tank, placing the pre-soaked product in the copper sulfate, and electroplating to prepare copper grid lines on the first copper seed part, and positioning the copper grid lines in the grooves. After the copper plating is completed, the product obtained after the copper plating is taken out of the copper plating tank and placed above the copper plating tank for 60s.
(7) And (3) placing a tin electroplating solution containing tin methylsulfonate in a tin plating tank, placing the product prepared in the step (6) in the tin electroplating solution, and electroplating to prepare tin grid lines on the copper grid lines and enable the tin grid lines to be positioned in the grooves.
(8) The patterned photoresist layer was removed using sodium hydroxide solution.
(9) And removing the second copper seed part by using a dilute sulfuric acid solution to obtain an electrode, thereby obtaining the copper interconnection solar cell.
Metallographic microscopy was performed on the copper interconnect solar cells prepared in example 1 and comparative example 1, respectively.
Referring to fig. 10 and 11, it can be seen that the line width of the electrode of the copper-interconnection solar cell prepared in example 1 is about 50 μm and the height is about 9 μm, which corresponds to the set value, whereas the line width of the electrode of the copper-interconnection solar cell prepared in comparative example 1 is about 115 μm and the height is about 16 μm, which is greater than the set value.
(II) the appearance of 1000 copper interconnect solar cells prepared in example 1 and comparative example 1 was examined, respectively.
The test results showed that the ratio of defective appearance was about 0.5% in the 1000 copper interconnect solar cells prepared in example 1, while the ratio of defective appearance was about 10% in the 1000 copper interconnect solar cells prepared in comparative example 1.
(III) short circuit currents (Isc) of the copper interconnect solar cells prepared in example 1 and comparative example 1 were respectively tested.
The test results showed that the short circuit current of the copper-interconnect solar cell prepared in example 1 was increased by 20mA compared to the short circuit current of the copper-interconnect solar cell prepared in comparative example 1, thereby indicating that the copper-interconnect solar cell prepared in example 1 has higher conversion efficiency than the copper-interconnect solar cell prepared in comparative example 1.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (10)

1. A method for improving the diffusion coating of a solar cell during electroplating, comprising the steps of:
providing a solar cell precursor, wherein a copper seed layer is arranged on the solar cell precursor, and a copper oxide layer is arranged on the surface of the copper seed layer;
removing the copper oxide layer;
preparing a photoresist layer on the copper seed layer after the copper oxide layer is removed;
sequentially exposing and developing the photoresist layer to obtain a patterned photoresist layer, wherein the patterned photoresist layer is provided with a slot, part of the copper seed layer is exposed to the slot, the copper seed layer exposed to the slot is defined as a first copper seed part, and the copper seed layer not exposed to the slot is defined as a second copper seed part;
electroplating copper on the first copper seed part to obtain a copper grid line; and
and removing the patterned photoresist layer and the second copper seed part.
2. The method for improving the diffusion plating of a solar cell according to claim 1, wherein after removing the copper oxide layer and before preparing the photoresist layer, the method further comprises the steps of:
forming a protective layer on the copper seed layer after the copper oxide layer is removed;
wherein the protective layer is removed at the time of the copper plating.
3. The method for improving the diffusion plating of a solar cell according to claim 2, wherein forming a protective layer on the copper seed layer after removing the copper oxide layer comprises the steps of:
reacting at least one of phenylbenzimidazole, alkylbenzimidazole, and alkylimidazole with the copper seed layer after removing the copper oxide layer to form the protective layer.
4. The method of improving the plating-on-diffusion of a solar cell of claim 3, wherein the protective layer is an organic protective layer comprising an organic solderable protective layer.
5. The method for improving the diffusion plating of a solar cell according to claim 2, wherein after removing the copper oxide layer and before forming the protective layer, the method further comprises a step of washing with water.
6. The method for improving the diffusion plating of a solar cell according to claim 2, wherein after the formation of the protective layer and before the preparation of the photoresist layer, the method further comprises the steps of washing with water and drying.
7. The method for improving the diffusion plating of a solar cell according to claim 1, wherein removing the copper oxide layer comprises the steps of:
the copper oxide layer is removed using an acidic solution.
8. The method for improving the diffusion plating of a solar cell of claim 7, wherein said acidic solution comprises sulfuric acid.
9. The method for improving the diffusion plating at the time of solar cell plating according to any one of claims 1 to 8, wherein in the step of plating copper, a dropping time of a copper plating solution including a copper sulfate solution is 3s to 6s.
10. The method for improving the diffusion plating of a solar cell according to any one of claims 1 to 8, wherein after the copper grid lines are obtained and before the patterned photoresist layer and the second copper seed portions are removed, the method further comprises the steps of:
electroplating tin on the copper grid line by adopting tin electroplating liquid to obtain a tin grid line;
the tin plating solution comprises tin methylsulfonate, and at least one of indium methylsulfonate, lead methylsulfonate and cerium sulfate.
CN202310596175.2A 2023-05-24 2023-05-24 Method for improving diffusion coating during electroplating of solar cell Pending CN116682895A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310596175.2A CN116682895A (en) 2023-05-24 2023-05-24 Method for improving diffusion coating during electroplating of solar cell

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310596175.2A CN116682895A (en) 2023-05-24 2023-05-24 Method for improving diffusion coating during electroplating of solar cell

Publications (1)

Publication Number Publication Date
CN116682895A true CN116682895A (en) 2023-09-01

Family

ID=87782891

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310596175.2A Pending CN116682895A (en) 2023-05-24 2023-05-24 Method for improving diffusion coating during electroplating of solar cell

Country Status (1)

Country Link
CN (1) CN116682895A (en)

Similar Documents

Publication Publication Date Title
US9876135B2 (en) Method for forming copper metallization over TCO of solar cells
CN115498050B (en) Solar cell and preparation method thereof
JP2010098232A (en) Solar battery and method of manufacturing solar battery
CN113380917A (en) Grid line preparation method, heterojunction battery preparation method and heterojunction battery
WO2024131295A1 (en) Method for preparing solar cell
EP2778262A1 (en) Copper plating solutions and method of making and using such solutions
CN116682895A (en) Method for improving diffusion coating during electroplating of solar cell
US20150027527A1 (en) Solar Cell and Process for Producing a Solar Cell
CN111969077B (en) Reworking method of solar cell
CN116247126B (en) Method for improving residual metal etched back of solar cell
CN105140345A (en) Heterojunction cell and preparation method thereof
CN116111005A (en) Method for improving poor copper and tin plating at non-grid line of solar cell
WO2024140484A1 (en) Solar cell and preparation method therefor
CN117423770A (en) Method for improving development residual glue of solar cell and application thereof
CN116247126A (en) Method for improving residual metal etched back of solar cell
WO2024131294A1 (en) Solar cell and preparation method therefor
CN115117183B (en) Heterojunction battery processing method
CN115799400A (en) Preparation method of solar cell
WO2024140454A1 (en) Preparation method for solar cell
CN112309834B (en) Processing method for driving offset gold bump in display chip
CN117423773A (en) Method for improving chemical tinning drain electrode layer of solar cell and application thereof
CN112635590B (en) Preparation method of high-efficiency monocrystalline silicon SE-PERC battery piece
CN215163230U (en) Patterned mask of single-sided or double-sided solar cell and solar cell
CN114725242B (en) Method for improving power generation efficiency of mass-produced cadmium telluride thin film battery
WO2024099415A1 (en) Battery cell preparation method and battery cell

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination