CN106816498A - A kind of method that mask layer is removed in solar cell metal grid lines preparation process - Google Patents

Abstract

The invention discloses a method for removing a mask layer during the preparation of a metal grid line of a solar cell, comprising the following steps: depositing an intrinsic amorphous silicon layer and an n-type amorphous silicon layer on one side of an n-type silicon substrate, and depositing an n-type amorphous silicon layer on the other side An intrinsic amorphous silicon layer and a p-type amorphous silicon layer, and a transparent conductive oxide film is deposited on the n-type amorphous silicon layer and the p-type amorphous silicon layer, and a barrier layer is deposited on the transparent conductive oxide layer; A seed layer is deposited on the barrier layer; a mask layer is covered on the seed layer, and a metal grid line pattern is formed after the mask layer is exposed and developed; the pattern area is electroplated with copper and tin to form Metal grid line: Carry the battery sheet through the tooling, enter the film removal room, remove the mask layer outside the grid line, and then enter the etching room, etch and remove the seed layer and barrier layer at its covering position, exposing the battery surface.

Description

Method for removing mask layer during preparation of solar cell metal grid lines

technical field

The invention relates to the field of solar cells, in particular to a method for removing a mask layer during the preparation of solar cell metal grid lines.

Background technique

Heterojunction solar cells are solar cells grown on a thin layer of amorphous silicon on a silicon substrate. They have the characteristics of simple structure, low process temperature, high conversion efficiency, and good temperature characteristics. They are one of the high-efficiency cells suitable for large-scale application. , has a good development prospect.

Taking the n-type silicon substrate as an example, the main structure of the heterojunction solar cell as shown in Figure 1 is: a thin-film intrinsic amorphous silicon layer and a P-type amorphous silicon emitter are successively deposited on the light-receiving surface of the n-type silicon substrate layer to form a heterogeneous PN junction with a thin-film intrinsic amorphous silicon interlayer; a transparent conductive oxide film is deposited on the double-sided doped amorphous silicon layer by sputtering, and finally a gate is formed on the transparent conductive oxide film. shaped metal electrodes.

At present, the conventional method of making grid-shaped metal electrodes is: electroplating with the help of tooling, taking out the cell from the tooling, transferring it to a horizontal device to remove the photoresist film, and then transferring it to the "battery flower basket" for etching to remove the metal stack. In this process, because the battery sheet needs to be transferred many times, the battery sheet is thin and brittle, so the battery sheet often breaks during the production process.

Contents of the invention

In view of the above problems, the present invention provides a method for removing the mask layer during the preparation of the metal grid wires of solar cells, which solves the rupture of the cells caused by the multiple transfers of the cells during the production process.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for removing the mask layer during the preparation of the solar cell metal grid line, comprising the following steps: depositing an intrinsic amorphous silicon layer on one side of the n-type silicon substrate and n-type amorphous silicon layer, on the other side deposit intrinsic amorphous silicon layer and p-type amorphous silicon layer, and deposit transparent conductive oxide thin film on n-type amorphous silicon layer and p-type amorphous silicon layer, in the A blocking layer is deposited on the transparent conductive oxide layer; a seed layer is deposited on the blocking layer; a mask layer is coated on the seed layer, and a metal grid line pattern is formed after the mask layer is exposed and developed; wherein the method It also includes the step of removing the mask layer: loading the solar cell into the tooling, exposing the seed layer in the metal grid line pattern, electroplating the grid line stack on the surface of the seed layer, and moving the tooling to remove the photosensitive layer after the electroplating grid line stacking is completed. In the dry film room, the mask layer is removed, and then moved to the etching room, where the seed layer and barrier layer at the covered position are removed with a chemical etching solution, exposing the surface of the battery.

Preferably, the mask layer is removed by spraying a sodium hydroxide or potassium hydroxide alkaline solution on the surface of the solar cell.

Preferably, the mask layer is a photosensitive dry film of photoresist material.

Preferably, the barrier layer is a Ti-based metal layer and a Ta-based metal layer, the Ti-based metal layer is a Ti, TiNx metal layer, and a TiW metal layer, and the Ta-based metal layer is a Ta, TaNx metal layer, the thickness of which is Between 1-50nm.

Preferably, the seed layer is one of a copper seed layer, a nickel seed layer, a silver seed layer, and an aluminum seed layer, and is formed by PVD sputtering, vapor deposition, or electroless plating, and its thickness is between 10-1000 nm. between.

Preferably, the grid line stack is composed of a first grid line stack and a second grid line stack; the first grid line stack is an electroplated copper layer, which is used as the main conductive layer of the metal grid line, and its thickness is 5 Between -40um; the second grid line stack is an electroplated tin layer, which is used as a soldering flux layer for the metal grid line and a protective layer for the copper stack, and its thickness is between 1-20um.

Preferably, said forming the metal grid line pattern after exposing and developing the mask layer includes applying a dry film, exposing, and developing to form a grid line pattern or screen printing to form a grid line pattern.

From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following advantages: the process is carried out continuously, and the removal of the mask layer does not need to take out the battery sheet from the tooling, which reduces the number of times the battery sheet is picked and placed, and greatly reduces Battery fragments.

Description of drawings

The accompanying drawings constituting a part of this application are used to provide further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

Fig. 1 is a schematic structural view of an n-type silicon substrate heterojunction solar cell;

Fig. 2 is the schematic flow sheet of making grid-like metal electrode of the present invention;

Fig. 3 is the structure diagram after depositing intrinsic layer, amorphous silicon thin film layer, conductive oxide layer, barrier layer of the present invention;

4 is a schematic structural view of the mask layer of the present invention after exposure and development to form a metal grid line pattern;

Fig. 5 is a schematic diagram of the structural domain of the present invention after electroplating grid lines on the surface of the seed layer;

Fig. 6 is a schematic diagram of the structure after removing the mask layer in the present invention;

FIG. 7 is a schematic diagram of the structure of the metal grid line after the metal stack is removed by etching according to the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

A method for removing a mask layer during the preparation of a solar cell metal grid line of the present invention comprises the following steps: depositing an intrinsic amorphous silicon layer and an n-type amorphous silicon layer on one side of an n-type silicon substrate, and depositing an intrinsic amorphous silicon layer on the other side An amorphous silicon layer and a p-type amorphous silicon layer, and a transparent conductive oxide film is deposited on the n-type amorphous silicon layer and the p-type amorphous silicon layer, and a barrier layer is deposited on the transparent conductive oxide layer; A seed layer is deposited on the barrier layer; a mask layer is covered on the seed layer, and the mask layer is exposed and developed to form a metal grid line pattern; electroplating is used to electroplate copper and tin on the pattern area to form a metal grid. Line; Carry the battery sheet through the tooling, enter the film removal chamber, remove the mask layer outside the grid line, and then enter the etching chamber, etch and remove the seed layer and barrier layer at its covering position, exposing the battery surface.

As shown in Figure 2, it is a schematic flow chart of making a grid-shaped metal electrode according to the present invention. The battery sheet 12 is loaded into the tooling 13, and the tooling 13 carries the battery sheet 12 into the spray film removal chamber 14 for film removal. After removing the mask layer The tooling 13 carries the cells 12 into the rinsing chamber 15 for rinsing. After rinsing, the tooling 13 carries the cells 12 into the etching chamber 16, removes the seed layer and barrier layer at the covered position with a chemical corrosion solution, and exposes the battery surface. Finally, the tooling 13 13 enters the rinsing chamber 15 carrying the cell sheet 12 again for rinsing. In the present invention, the solar cells are carried into the electroplating chamber by the tooling for copper electroplating and tin plating, and then enter the film removal chamber. The film removal chamber is equipped with a device for spraying the film removal solution. The barrier film is separated from the surface of the battery, and the mask layer is removed; rinse it after processing; enter the etching chamber, the etching chamber is filled with an etching solution, and the tooling carries the battery piece into the etching solution. After the metal stack is removed by etching, rinse it with clean water and remove blow dry.

In a specific embodiment, the following steps are included:

Step 1, by depositing an intrinsic amorphous silicon layer 2 on one side of the n-type silicon substrate 1 after being etched by an alkaline or acidic solution and using a CVD method to prepare an n-type amorphous silicon layer 3, and depositing an intrinsic amorphous silicon layer on the other side 2 and p-type amorphous silicon layer 4, wherein the surface reflectance of n-type silicon substrate 1 is less than 5% in the wavelength range of 300-1100nm, and then PVD sputtering is used to form n-type amorphous silicon layer 3 and p-type A transparent conductive oxide film 5 is deposited on the amorphous silicon layer 4, wherein the transparent conductive oxide film 5 adopts an ITO (indium tin oxide) layer, or an indium oxide layer doped with other elements, and its characteristic is that light passes through a material with a thickness of 100 nanometers. , its transmittance must be greater than 90% at least, the resistivity of the transparent conductive oxide film 5 is usually less than 3.5×10-4ohm-cm, and its thickness is between 50-120nm. Deposit a barrier layer 6 on the barrier layer 6; the barrier layer 6 adopts a Ti-based metal layer, and its thickness is between 1-50nm; and then simultaneously deposit a seed layer 7 on the barrier layer 6 by electroless plating or PVD sputtering, and the seed layer 7 is copper The thickness of the seed layer is between 10-1000 nm, as shown in FIG. 3 .

Step 2. Cover the seed layer 7 with a layer of mask layer 8, the mask layer 8 is a photosensitive dry film of photoresist material, and then the mask layer 8 is exposed and developed to form a metal grid line pattern 9, as shown in Figure 4 shown. The forming of the metal grid line pattern 9 after the mask layer 8 is exposed and developed includes applying a dry film, exposure, and development to form a grid line pattern or screen printing to form a grid line pattern.

Step 3: Install the solar cell into the tooling, expose the seed layer 7 in the metal grid pattern 9 , and then electroplate the grid line stack on the surface of the seed layer 7 . Wherein the grid line stack is composed of a first grid line stack 10 and a second grid line stack 11, the first grid line stack 10 is an electroplated copper layer, as the main conductive layer of the metal grid line, its thickness is between 5- Between 40um; the second gate line stack 11 is an electroplated tin layer, which is used as a solder flux layer for the metal gate line and a protective layer for the electroplated copper layer, and its thickness is between 1-20um, as shown in FIG. 5 .

Step 4. After the electroplating grid line lamination is completed, the tooling is moved to the photosensitive dry film removal chamber, and the mask layer 8 is removed, as shown in FIG. 6 . The mask layer 8 is removed by spraying sodium hydroxide or potassium hydroxide alkaline solution on the surface of the solar cell.

Step 5, move the solar cell after removing the mask layer 8 to an etching chamber, remove the seed layer 7 and the barrier layer 6 at the covered position with a chemical etching solution, and expose the surface of the cell. So far, the fabrication of the entire grid line is completed, and finally the metal grid line on the surface of the cell is shown in FIG. 7 .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (7)

1. a kind of method that mask layer is removed in solar cell metal grid lines preparation process, it is characterised in that： It is as follows including step：

In the face deposition intrinsic amorphous silicon layer of n-type silicon substrate one and N-shaped amorphous silicon layer, another side deposition is originally Amorphous silicon layer and p-type amorphous silicon layer are levied, and is deposited on N-shaped amorphous silicon layer and p-type amorphous silicon layer saturating Bright conductive oxide film, barrier layer is deposited on the including transparent conducting oxide layer；In the stop Deposited seed layer on layer；One layer of mask layer is covered on the seed layer, by mask layer by shape after exposure imaging Into metal grid lines pattern；Wherein methods described also includes removal mask layer step：Solar cell is filled Enter in frock, Seed Layer is exposed in metal grid lines pattern, in Seed Layer electroplating surface grid line lamination, Frock is moved into removal photosensitive dry film room after completing plating grid line lamination, mask layer is removed, then moved to Etching chamber, Seed Layer and the barrier layer of its covering position are removed with chemical corrosion liquid, expose battery table Face.

2. the side of mask layer is removed in solar cell metal grid lines preparation process according to claim 1 Method, it is characterised in that：Described remove mask layer sprays NaOH using to solar cell surface Or potassium hydroxide basic solution.

3. the side of mask layer is removed in solar cell metal grid lines preparation process according to claim 1 Method, it is characterised in that：The mask layer is the photosensitive dry film of photoresist.

4. the side of mask layer is removed in solar cell metal grid lines preparation process according to claim 1 Method, it is characterised in that：The barrier layer is Ti metalloids layer, Ta metalloids layer, the Ti eka-golds Category layer is Ti, TiNx metal level, TiW metal levels, and the Ta metalloids layer is Ta, TaNx metal Layer, its thickness is between 1-50nm.

5. the side of mask layer is removed in solar cell metal grid lines preparation process according to claim 1 Method, it is characterised in that：The Seed Layer is copper seed layer, nickel Seed Layer, silver-colored Seed Layer, aluminium seed One kind in layer, is generated using PVD sputtering methods, vapour deposition method or chemical-electrical plating method, and its thickness exists Between 10-1000nm.

6. the side of mask layer is removed in solar cell metal grid lines preparation process according to claim 1 Method, it is characterised in that：The grid line lamination is made up of the first grid line lamination, the second grid line lamination；Institute The first grid line lamination is stated for copper electroplating layer, used as metal grid lines host conductive layer, its thickness is in 5-40um Between；Second grid line lamination is plating tin layers, used as the protection for helping layer and copper lamination of metal grid lines Layer, its thickness is between 1-20um.

7. the side of mask layer is removed in solar cell metal grid lines preparation process according to claim 1 Method, it is characterised in that：It is described to include adopting by forming metal grid lines pattern after exposure imaging by mask layer Grid line pattern is made with patch dry film, exposure, development or silk-screen printing makes grid line pattern.