WO2019042084A1

WO2019042084A1 - Method for selective texture preparation on surface of crystalline silicon wafer

Info

Publication number: WO2019042084A1
Application number: PCT/CN2018/098588
Authority: WO
Inventors: 季静佳; 覃榆森
Original assignee: 苏州易益新能源科技有限公司
Priority date: 2017-09-04
Filing date: 2018-08-03
Publication date: 2019-03-07
Also published as: CN109427930A; CN109427930B

Abstract

The present invention discloses a method for texture preparation by carrying out chemical solution etching on the surface of a crystalline silicon wafer. The method for texture preparation by carrying out chemical solution etching on the surface of a crystalline silicon wafer disclosed in the present invention applies a texturing additive to the surface of a crystalline silicon wafer to be textured prior to a chemical solution etching step. In this way the method differs from the current commonly used method of direct addition of a texturing additive to a chemical etching texturing solution. The texturing additive applied on the surface of the crystalline silicon wafer does not react with the crystalline silicon wafer, and the surface of the crystalline silicon wafer applied with the texturing additive is wetted by the chemical etching solution, so as to carry out chemical etching on the surface of the crystalline silicon wafer for texture preparation.

Description

Method for selectively preparing suede on the surface of crystalline silicon wafer

Technical field

The present invention relates to a technique for preparing a solar cell, and more particularly to a method for preparing a suede by chemical solution etching on the surface of a crystalline silicon wafer. The method for preparing the suede by chemical solution etching on the surface of the crystalline silicon wafer has the characteristics that the chemical solution corrosion can be selectively performed on some specific areas of the surface of the crystalline silicon wafer to prepare the suede, and is particularly suitable for preparing solar energy with high photoelectric conversion efficiency. Applied on the battery.

technical background

The suede on the surface of the crystalline silicon wafer plays an important role in improving the photoelectric conversion efficiency of the solar cell. The so-called suede refers to a series of regular or irregular heights and different surface shapes formed on the surface of a crystalline silicon wafer. When sunlight is incident on the surface of the wafer having the pile surface, the reflected light can produce a secondary or multiple incident effect between the pile surfaces on the surface of the crystal silicon wafer. In other words, the surface of the surface of the crystalline silicon wafer can enhance the absorption of sunlight by the solar cell, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

There are various methods for preparing suede on the surface of a crystalline silicon wafer, such as a chemical solution etching method, a plasma etching method, and a laser etching method. The most widely used method for preparing suede on the surface of crystalline silicon wafers in industrial production is a method for preparing a suede surface by chemical solution etching on the surface of a crystalline silicon wafer, that is, a chemical solution etching and texturing method. The so-called chemical solution corrosive method is a method of etching crystalline silicon by a chemical solution to form a suede on the surface of the crystalline silicon. For example, the surface of the surface of the monocrystalline silicon wafer is generally formed by etching a single crystal silicon wafer by an alkaline chemical solution, and the surface of the surface of the polycrystalline silicon wafer is generally formed by etching with an acidic solution.

In industrial production, in order to improve the quality of the surface of the crystalline silicon wafer, various kinds of texturing additives are generally added in an alkaline chemical etching solution or in an acidic chemical etching solution. For example, EP 0 774 424 A1 discloses a texturing additive for an alkaline polyethylene glycol solution which, after the addition of such a texturing additive, contributes to the production of a suede having a small and uniform suede size. CN2011102128769 discloses another texturing additive. After the texturing additive is added to the acidic chemical etching solution, the polycrystalline silicon sheet is corroded by a chemical etching solution containing the texturing additive, and a smaller and more uniform pile can be formed on the surface of the polycrystalline silicon sheet. surface. Various types of texturing additives have been commonly used in the current stage of mass production of crystalline silicon solar cells.

Although the suede quality of the surface of the crystalline silicon wafer was significantly improved after the use of various kinds of texturing additives, the stability of the suede quality per batch still had large fluctuations. The reason is that the quality of the suede after the surface of the crystalline silicon wafer is corroded by chemical solution depends not only on the texturing additive, but also on other texturing conditions. For example, since the effective content of the texturing additive in the etching solution and the content of the corrosion product sodium silicate are constantly changing with the texturing reaction, the quality of the surface of the crystalline silicon wafer is also changed. In order to ensure the stability of the suede quality, in the production of the velvet, the texturing process must be continuously adjusted according to the specific conditions of the batch of velvet results. This not only causes difficulty in the production of the texturing, but also does not maintain the consistency of the surface of the surface of the crystalline silicon wafer after each batch of the velvet, which is not conducive to the stability of production.

With the deepening of research on improving the photoelectric conversion efficiency of crystalline silicon solar cells, new challenges have been raised for the texturing process. For example, it has been found that if the light-receiving surface of a crystalline silicon solar cell or the main light-receiving surface of a crystalline silicon solar cell is subjected to a texturing process and a flat surface is maintained on the other surface thereof, the photovoltaic of the crystalline silicon solar cell can be improved. Conversion efficiency. In order to achieve the effect that the surface of the crystalline silicon wafer has a suede surface and the other surface has a smooth surface, the current practice is to first simultaneously soften the two surfaces of the crystalline silicon wafer, and then polish one of the surfaces. Obviously this method increases the cumbersomeness of production.

Summary of the invention

In view of the above drawbacks of the prior art, the present invention discloses a method for preparing a suede by chemical etching of a surface of a crystalline silicon wafer.

One of the objects of the present invention is to find a method for preparing a suede by chemical solution etching on the surface of a crystalline silicon wafer, which can improve the stability of the texturing process.

Another object of the present invention is to find a method for preparing a suede by chemical solution etching on the surface of a crystalline silicon wafer, which can meet the requirements for preparing a high-efficiency solar cell, and can perform selective texturing on the surface of the crystalline silicon wafer.

A final object of the present invention is to find a method for preparing a suede by chemical solution etching on the surface of a crystalline silicon wafer, which can be applied to the production of all crystalline silicon solar cells, including monocrystalline silicon solar cells, quasi-monocrystalline silicon solar cells. Batteries, polycrystalline silicon solar cells, n-type crystalline silicon solar cells, and p-type crystalline silicon solar cells expand the range of applications of the present invention.

In order to achieve the above object, the present invention discloses a method of preparing a suede by chemical solution etching on the surface of a crystalline silicon wafer. The method for preparing the suede by chemical solution etching on the surface of the crystalline silicon wafer disclosed in the present invention is different from the commonly used method of directly adding the texturing additive to the chemical etching and dyeing solution, but performing chemistry on the crystalline silicon wafer. Prior to the solution etching process, the texturing additive is applied to the surface of the crystalline silicon wafer to be textured. The texturing additive coated on the surface of the crystalline silicon wafer does not react with the crystalline silicon wafer, and then the chemical etching solution is wetted by the surface of the crystalline silicon wafer coated with the texturing additive, and the surface of the crystalline silicon wafer is chemically etched. The step of preparing the suede.

A method for preparing a suede by chemical solution etching on the surface of a crystalline silicon wafer of the present invention comprises the following steps:

1) coating a texturing additive on the surface of the crystalline silicon wafer on which the suede is to be prepared;

2) The surface of the crystalline silicon wafer coated with the texturing additive is contacted with a chemical etching solution, and the surface of the crystalline silicon wafer is subjected to chemical solution etching to prepare a suede surface.

The texturing additive of the present invention is obviously not the reactant of the chemical etching solution for etching the silicon wafer, or the texturing additive of the present invention does not appear in the reaction equation of the chemical etching solution for etching the silicon wafer. For example, hydroxide ions (OH ^- ) in the reaction of alkali etching solution, hydrofluoric acid (HF) in the reaction of acid etching solution, various oxidation (nitric acid, hydrogen peroxide, etc.) and various metals in the metal induced corrosion reaction The elements are all reactants of the chemical etching solution for etching the silicon wafer and are not in the category of the texturing additive of the present invention.

The texturing additive of the present invention is often also referred to as a texturing accelerator, or other name. The effect of the texturing additive of the present invention is to increase the uniformity of the pile formed on the surface of the crystalline silicon wafer and to reduce the reflectance. Further, the other functions of the texturing additive of the present invention include shortening the time of texturing on the surface of the crystalline silicon wafer, reducing the amount of chemicals, reducing the cost of chemicals, and improving the stability of production.

The method of the present invention for chemically etching the surface of a crystalline silicon wafer has the advantage that since the texturing additive is directly coated on the surface of the crystalline silicon wafer before the surface is chemically etched on the surface of the crystalline silicon wafer, the texturing additive is directly coated on the surface of the crystalline silicon wafer. In the subsequent step of chemically preparing the suede, the coated texturing additive can directly produce and rapidly promote the texturing on the surface of the crystalline silicon, effectively utilizing the texturing additive.

In the process of chemically etching the surface of the crystalline silicon wafer to prepare the suede, the quality of the suede and the uniformity of the suede formed on the surface of the crystalline silicon wafer are related to the concentration of the texturing additive on the surface of the crystalline silicon wafer. Since the method of preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention is to apply the texturing additive on the surface of the crystalline silicon wafer, in the texturing step of the method for preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention, It is easy to maintain the same concentration of the texturing additive on the surface of all crystalline silicon wafers throughout the production process, which guarantees stable production.

In some cases, the texturing additive can easily fail in some chemical etching solutions, which can make the use of the texturing additive too large, resulting in the disadvantages of unstable production and high production cost. Therefore, another advantage of the present invention is that since the present invention does not directly add the texturing additive to the chemical etching solution, it is ensured that the same concentration of the texturing additive exists on the surface of each of the crystalline silicon wafers to ensure production stability.

The method for preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention is to apply the texturing additive on the surface of the crystalline silicon wafer, and the reaction of forming the suede on the surface of the crystalline silicon wafer can be prepared by contacting the crystalline silicon wafer with chemical etching. The suede solution instantaneously occurs, so that the method of preparing the suede by chemical etching of the surface of the crystalline silicon wafer of the present invention has another advantage in that the amount of corrosion of the crystalline silicon wafer can be reduced. Reducing the amount of thinning of the crystalline silicon wafer during chemical etching to prepare the suede, that is, reducing the consumption of chemicals in the etching solution and reducing the production cost of the texturing step. At the same time, the time for preparing the suede by chemical corrosion is shortened, the production capacity of the equipment is increased, or the investment cost of the equipment is reduced.

A significant advantage of the method of making a crystalline silicon solar cell suede of the present invention is that the method of the present invention can produce a suede on a partial surface area of a crystalline silicon wafer without producing a suede on other surface areas. Since the present invention applies the texturing additive directly on the surface of the crystalline silicon wafer, the effect of the texturing additive can be quickly exerted in the step of chemically etching the suede on the area of the crystalline silicon wafer to which the texturing additive is applied. The effect is that the suede is quickly formed on the area. On the area where the texturing additive is not applied, the formation of the suede is very slow, and the effect of local chemical corrosion to prepare the suede is achieved. For example, the purpose of texturing on one of the surfaces of a crystalline silicon wafer can be easily achieved by using the present invention, that is, the purpose of single-side texturing is achieved.

A further advantage of the present invention is that the method of chemically etching the suede of the present invention can extend the range of choice of the texturing additive. For example, some of the texturing additives have a problem of low solubility in a chemically corrosive solution for chemically corroded suede, and do not function as a texturing additive in the chemical etching solution. Since the method of preparing the pile surface on the surface of the crystalline silicon wafer of the present invention does not add the texturing additive to the chemical etching solution, as long as such a texturing additive can uniformly cover the surface of the crystalline silicon wafer, these texturing additives are in the present invention. The chemical etching process in the preparation of the suede works well. For another example, some of the texturing additives and the chemically prepared chemical solution of the suede will react quickly and lose the effect of the texturing additive. After the method of the present invention, these texturing additives play a rapid role in the step of chemically preparing the suede, so that as long as the reaction time of these texturing additives and chemical etching to prepare the suede chemical solution is longer than the texturing time, these systems are prepared. The velvet additive can still exert a good texturing promotion effect in the method of chemically etching the suede of the present invention.

DRAWINGS

Figure 1. Schematic diagram of the immersion coating and velvet additive of the present invention

Figure 2. Schematic diagram of the spray coating and texturing additive of the present invention

Detailed ways

The invention may be further described in detail with reference to the drawings. It is apparent that these descriptions are not intended to limit the invention. Various other suitable combinations, modifications, or alterations can be made in accordance with the present invention without departing from the spirit and scope of the invention. These respective combinations, changes and modifications are intended to be included within the scope of the appended claims.

The method for preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention is to apply the texturing additive to the surface of the crystalline silicon wafer to be prepared into a suede surface before chemically etching the suede. In some embodiments, the manner in which the texturing additive is applied may be a soak coating of the texturing additive. In the step of coating the texturing additive by the immersion method, referring to FIG. 1, the texturing additive 30 is poured into the texturing additive tank 20, and the crystalline silicon wafer 10 is placed in the texturing additive tank 20, so that the texturing additive 30 is submerged and moisturized. Wet crystalline silicon wafer 10 surface. Thus, when the crystalline silicon wafer 10 is removed from the texturing additive tank 20, the texturing additive 30 is coated on the surface of the crystalline silicon wafer 10. The immersion coating velvet additive step of the method for preparing the suede on the surface of the crystalline silicon wafer by chemical etching may be the vertical immersion shown in FIG. 1 or the horizontal immersion method may be used to carry out the coating velvet additive of the present invention. step.

In some other embodiments of the method of the present invention for preparing a pile surface by chemical etching on the surface of a crystalline silicon wafer, a method of spraying the texturing additive 30 on the surface of the crystalline silicon wafer may be employed. Referring to Fig. 2, the texturing additive 30 is placed in the texturing additive tank 20, and the texturing additive 20 is sprayed on the surface of the crystalline silicon wafer 10 through the texturing additive nozzle 40 by a liquid level difference or a pressure difference. In some embodiments, the texturing additive showerhead 40 can be comprised of one or more apertures, or a showerhead. In the embodiment of the method for preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention, in order to achieve the purpose of uniform coating, the crystalline silicon wafer 10 may be moved when the texturing additive is sprayed, and the texturing additive nozzle 40 may be moved. .

In still other embodiments of the method of the present invention for chemically etching the surface of a crystalline silicon wafer, the texturing additive 30 may be applied to the surface of the crystalline silicon wafer by spin coating. An advantage of applying the texturing additive 30 to the surface of the crystalline silicon wafer by spin coating is that the texturing additive 30 can be uniformly coated on the surface of the crystalline silicon wafer. Another advantage of the spin coating process is that the coated texturing additive can be dried on the surface of the crystalline silicon wafer faster after the spin coating is completed.

In other embodiments, other coating methods can be used to implement the coating additive step of the present invention, for example, a texturing method can be used to apply a texturing additive to the surface of a crystalline silicon wafer. The texturing additive 30 may also be applied to the surface of the crystalline silicon wafer by ultrasonic atomization of the texturing additive 30. The application of the texturing additive 30 to the surface of the crystalline silicon by ultrasonic atomization can increase the use rate of the texturing additive 30, and can also improve the uniformity of the coated texturing additive 30.

The texturing additive 30 of the present invention for chemically etching the surface of a crystalline silicon wafer to form a pile may be a variety of compounds capable of promoting the formation of the desired suede on the surface of the crystalline silicon. In the texturing additive, one or more compounds are included. The role of the additive is to make the texturing process easier to control; to make the prepared suede size more uniform; the suede size is smaller; the crystalline silicon wafer has a lower reflectance; the conditions of the texturing production are easier to control and stabilize; Conducive to surface cleaning. In summary, the texturing additive is a mixture of one or more compounds that improve the texturing and texturing processes. In other words, the texturing additive is a compound which helps to improve the suede quality of the surface of the crystalline silicon, for example, a compound which can reduce the size of the suede, improve the uniformity of the suede and reduce the reflectance, or a help system. Cashmere production, for example, can shorten the time of texturing, reduce the amount of chemicals used, reduce the cost of chemicals, and improve the stability of production.

The method of applying the texturing additive on the surface of the crystalline silicon wafer by the method of chemically etching the surface of the crystalline silicon wafer of the present invention may be a coating of a texturing additive. In other applications, more than one type of texturing additive may be applied. For example, in some applications of the present invention, special compounds are required to adsorb the texturing additive to the surface of the crystalline silicon wafer to ensure that the texturing additive maximizes its effect as a texturing additive when the chemical solution corrodes crystalline silicon. In these applications of the invention, it is necessary to apply two or more types of texturing additives. When more than one texturing additive is applied, the step of applying the additive may be one or more steps of coating the texturing additive.

The method of the present invention for chemically etching the surface of a crystalline silicon wafer to prepare a pile is suitable for all types of crystalline silicon wafers, such as single crystal silicon wafers, polycrystalline silicon wafers, and cast single crystal silicon wafers. Further, these types of silicon wafers may be p-type silicon wafers, such as boron doped silicon wafers, or n-type silicon wafers, such as phosphorus doped silicon wafers.

The crystalline silicon wafer 10 in the step of coating the texturing additive for the method of chemically etching the surface of the crystalline silicon wafer of the present invention to form a pile may be an original silicon wafer, such as an original silicon wafer purchased directly from a silicon wafer supplier. The surface of these original silicon wafers not only retains the damaged layer produced during the cutting process, but may also retain more or less unclean chemical contaminants such as cutting lubricants.

In some embodiments of the invention, crystalline silicon wafer 10 may be a raw silicon wafer that has been chemically pretreated. For example, the original silicon wafer may be subjected to a chemical initial bubble treatment, and then the coating and texturing additive step in the method of preparing the pile surface by chemical etching on the surface of the crystalline silicon wafer of the present invention may be carried out. In large-scale production practices, the purpose of chemically priming silicon wafers is to clean chemical contaminants that remain on the original silicon wafer, such as some organic chemical contaminants. The chemical initial bubble step is performed before the surface of the crystalline silicon wafer is prepared, which not only ensures that the surface of the crystalline silicon wafer does not contain any contaminants after being prepared, and more forms various spots on the surface of the crystalline silicon.

In some other embodiments of the present invention, the chemically pretreated crystalline silicon wafer 10 may be a crystalline silicon wafer that cleans the damaged layer on the surface of the produced crystalline silicon wafer during the cutting process, that is, the original silicon wafer. The coating and texturing additive step of the method of preparing the suede by chemically treating the damaged layer and then performing the surface chemical etching of the crystalline silicon wafer of the present invention. The method for preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention is applied to the texturing silicon wafer after the damaged layer is removed, and when the method of fabricating the surface of the crystalline silicon wafer of the present invention for chemically etching the suede is performed, Significantly shorten the time of softening.

In other embodiments of the present invention, the chemically pretreated crystalline silicon wafer 10 may be a chemically polished crystalline silicon wafer, that is, the original silicon wafer is first subjected to chemical polishing, and then the crystal of the present invention is implemented. A step of coating a texturing additive for a method of chemically etching a surface of a silicon wafer to prepare a pile. The method for preparing a suede by chemical etching on the surface of a crystalline silicon wafer of the present invention is applied to a crystallized silicon wafer after chemical polishing, and after performing the texturing step of the method for preparing a suede by chemical etching on the surface of the crystalline silicon wafer of the present invention, A very uniform suede having a suede size of about 1 micrometer was prepared on the surface of the crystalline silicon wafer.

The crystalline silicon wafer 10 can also be a crystalline silicon wafer after some physical processing of the original silicon wafer. For example, in order to reduce the surface reflectance of the polycrystalline silicon wafer after preparing the pile surface, the laser processing may be performed before the step of applying the texturing and dyeing additive of the method for preparing the suede surface by chemical etching on the surface of the crystalline silicon wafer, and the polycrystalline silicon sheet is added. The surface is rough. These increased surface roughness can effectively reduce the reflectivity of the surface of the polysilicon sheet after the preparation of the pile.

The crystalline silicon wafer 10 prior to the step of applying the texturing additive for carrying out the method of chemically etching the surface of the crystalline silicon wafer of the present invention may be dry, for example, a raw silicon wafer without any pretreatment. Or a crystalline silicon wafer which has been subjected to pretreatment and dried by a crystalline silicon wafer, for example, a crystalline silicon wafer which has been chemically bubbled and dried.

In still other embodiments of the present invention, the crystalline silicon wafer 10 before the step of applying the texturing additive for the method of chemically etching the surface of the crystalline silicon wafer of the present invention can be wet, neither dried, for example, After the crystalline silicon wafer is cleaned by chemical primary foaming and deionized water, the coating and texturing additive step of the method for preparing the suede by chemical etching on the surface of the crystalline silicon wafer of the present invention is directly carried out.

One of the advantages of the method of chemically etching the surface of the crystalline silicon wafer of the present invention to prepare a pile surface is that a partial surface of the crystalline silicon wafer 10 can be subjected to the preparation of a pile surface. As shown in FIG. 2, after the step of coating the texturing additive of the crystalline silicon wafer 10 by the method of chemically etching the surface of the crystalline silicon wafer of the present invention, the texturing additive is merely coated on the crystalline silicon wafer 10. surface. If the lower surface of the crystalline silicon wafer 10 is no longer coated with the texturing additive, the optimized texturing process of the surface of the crystalline silicon wafer of the present invention for chemically preparing the suede can be performed by chemical etching to prepare the suede only on the upper surface. The surface, that is, only the upper surface of the crystalline silicon wafer 10 has a pile surface.

Further, the method of preparing the pile surface by chemical etching of the surface of the crystalline silicon wafer of the present invention can also prepare a pile surface on a specific area on one surface of the crystalline silicon wafer 10. For example, the present invention can coat the texturing additive 30 only on certain areas of the upper surface of the crystalline silicon wafer 10 that needs to be textured. The optimized texturing process of the surface of the crystalline silicon wafer of the present invention for the process of preparing the pile surface allows the chemical etching to produce the pile surface only in the area of the coated texturing additive on the upper surface of the crystalline silicon wafer 10.

After the step of applying the texturing additive for the method of preparing the suede by chemically etching the surface of the crystalline silicon wafer of the present invention, the step of chemically etching the suede by the method of preparing the surface of the crystalline silicon wafer of the present invention to prepare the suede is carried out. In some embodiments of the invention, the texturing additive 30 on the surface of the crystalline silicon wafer 10 may be dried first. In other embodiments, the step of chemically preparing the suede by directly performing the method of preparing the suede by surface chemical etching of the crystalline silicon wafer of the present invention after the step of applying the texturing additive.

According to the characteristics of the crystalline silicon wafer 10 and the characteristics of the texturing additive 30, in combination with the different requirements for various suede surfaces, the step of chemically etching the surface of the crystalline silicon wafer of the present invention by chemical etching to prepare the suede may be carried out by using a base. The solution is chemically etched to prepare the suede, and the acid solution can also be used for chemical etching to prepare the suede. For example, the step of chemically etching the surface of the single crystal silicon wafer and the surface of the quasi-monocrystalline silicon wafer using an alkaline chemical solution to prepare a pile surface is carried out. In the step of preparing the suede by alkaline chemical etching of the present invention, an inorganic base or an organic base may be employed. Optimized alkaline solution chemical etching produces a suede temperature between 60 degrees Celsius and 100 degrees Celsius. Optimized alkaline solution chemical etching The alkali concentration in the alkaline solution of the suede is between 0.5% and 5%. The chemical etching time of the prepared suede by alkaline solution chemical etching is between 5 minutes and 30 minutes.

In some embodiments of the present invention, according to specific implementation conditions, other various additives may be added to the alkaline solution prepared by chemical etching of the alkaline solution, for example, 1% to 10% of the difference may be added to the alkaline solution. Propanol.

The step of chemically etching the surface of the crystalline silicon wafer of the present invention by chemical etching to prepare the pile surface can also be carried out by chemical etching using an acidic solution to prepare the pile surface. For example, a mixed acid solution of nitric acid and hydrofluoric acid can be used.

The step of chemically etching the surface of the crystalline silicon wafer of the present invention by chemical etching to prepare the pile surface can be carried out by the step of preparing the pile surface by using the groove gap. In the method of preparing the pile surface in the groove gap, the crystalline silicon wafer 10 is usually vertically immersed in a solution prepared by chemical etching to prepare a pile surface, and the step of chemically etching to prepare the pile surface is completed. The step of chemically etching the suede by the method of chemically etching the surface of the crystalline silicon wafer of the present invention to prepare the pile can also be carried out by horizontally preparing the pile. In the method of continuously preparing the pile, the crystalline silicon wafer 10 is usually subjected to chemical etching to prepare a suede solution under the conveyance of various conveying means such as various rollers, and the step of chemically etching to prepare the pile is completed.

Specific embodiment

Example 1

First, the original p-type single crystal silicon wafer is subjected to initial foaming in order to clean the organic contaminants and partially damaged layers remaining during the slicing and packaging process. The single crystal silicon wafer is washed with deionized water after the initial bubble, and then a velvet additive (for example, basic polyethylene glycol) is coated on the surface of the silicon wafer by a soaking method, and the silicon wafer is horizontally placed at a temperature of 80. Celsius, a 1.5% sodium hydroxide chemical etching solution doped with an appropriate amount of IPA continuously wets the upper surface of the silicon wafer, and the method of chemically etching the crystalline silicon wafer of the present invention to prepare a horizontal suede process is prepared. After 20 minutes, the process of preparing the suede by chemical etching of the crystalline silicon wafer of the present invention is completed. After washing and drying, the average size of the pyramidal suede was measured to be 2 μm on the upper surface of the crystalline silicon wafer, the average reflectance of the upper surface was 10.2%, and the average reflectance of the lower surface was 20.5%.

Example 2

The n-type single crystal silicon wafer sliced by diamond wire uses inkjet printing method to put the texturing additive (such as alkaline polyethylene glycol) on the light receiving area of the silicon wafer, so that there is no texturing additive on the electrode area of the silicon wafer. After the softening additive is dried, the silicon wafer is placed in a mixed solution of 40% Celsius, 4% tetramethylammonium hydroxide and an appropriate amount of IPA. After 10 minutes, the crystal silicon wafer of the present invention is chemically corroded to prepare a suede process. Finished. After cleaning and drying, the average size of the pyramidal suede was measured on the surface of the upper surface of the crystalline silicon wafer coated with the texturing additive to be 1 micrometer, on the surface of the crystalline silicon not covered by the texturing additive. The pyramidal suede has an average size of 5 microns.

Example 3

The step of applying a texturing additive on the surface of the crystalline silicon wafer of the present invention is carried out by spin coating a fluffing additive (for example, a mixture of PEG 200 and polyvinylpyrrolidone) onto the upper surface of the p-type polycrystalline silicon wafer. After the upper surface of the crystalline silicon wafer is coated with the texturing additive, it is directly placed in a continuous acid solution chemical etching and texturing device, and the horizontal etching system for chemically etching the crystalline silicon wafer to prepare the suede according to the present invention is implemented. Velvet step. The chemical etching conditions of the continuous acid solution are hydrofluoric acid: nitric acid: water = 1:4:3, and the etching temperature is 5 degrees. After 2 minutes, the process of preparing the suede by chemical etching of the crystalline silicon wafer of the present invention is completed. After washing and drying, the average reflectance was 20% on the upper surface of the crystalline silicon wafer, and the average reflectance on the lower surface was 23%.

Example 4

A surface of the original n-type polycrystalline silicon wafer is roughened by a laser roughening technique, and then the surface of the silicon wafer to be roughened is subjected to the step of coating the surface of the crystalline silicon wafer with a texturing additive. In the present embodiment, the coating and texturing additive is divided into two steps. First, triethanolamine is first coated on the surface of the crystalline silicon wafer by a spraying method, and polyvinyl alcohol is coated on triethanolamine by a spraying method. The texturing additive is coated on the upper surface of the crystalline silicon wafer, blown dry, and then placed in a continuous acid-solution tank type chemical etching and texturing apparatus to implement the horizontal etching system for chemically etching the crystalline silicon wafer of the present invention. Velvet step. The chemical etching and texturing device contains hydrofluoric acid: nitric acid: water = 1:4:2.5, and the etching temperature is 5 degrees. After 2 minutes, the process of preparing the suede by chemical etching of the crystalline silicon wafer of the present invention is completed. After washing and drying, an average reflectance of 15% was measured on the roughened surface of the silicon wafer, and the reflectance of the other surface of the silicon wafer was 26%.

Claims

A method for preparing a suede surface by chemical solution etching on a surface of a crystalline silicon wafer, characterized in that the method applies a texturing silicon wafer to a crystal silicon wafer before performing a chemical solution etching on the surface of the crystalline silicon wafer to prepare a suede surface Surface, including the following steps:

(1) coating a texturing additive on the surface of the crystalline silicon wafer;

(2) Preparing a suede by chemical solution etching on the surface of the crystalline silicon wafer.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claim 1, wherein the effect of the texturing additive is assisted in the subsequent step of preparing a suede by chemical solution etching. Improve the surface quality of the crystalline silicon wafer and the texturing additive that contributes to the production of the texturing.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claims 1 and 2, wherein said texturing additive is coated on at least a part of the surface area of the entire surface area of the crystalline silicon wafer on.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claims 1 and 2, wherein said coated texturing additive is at least one type of texturing additive, said The coating step is at least one coating step.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claims 1 and 2, wherein the method of coating the surface of the crystalline silicon wafer with the texturing additive may be by soaking The method comprises applying the texturing additive to the surface of all the crystalline silicon wafers, or coating the texturing additives on the crystal by any one of spraying, spin coating and printing, or a combination of coating techniques therebetween. A part of the surface of the silicon wafer.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claims 1 and 2, wherein the surface of the crystalline silicon wafer is before the step of applying the additive on the surface of the crystalline silicon wafer Dry, or not dried.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claims 1 and 2, characterized in that after the step of applying an additive on the surface of the crystalline silicon wafer, the anti-texturing additive can be The drying step may be carried out without performing a drying step on the texturing additive.
The method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claim 1, wherein the crystalline silicon wafer is an original crystalline silicon wafer before the step of coating the texturing additive, It may be a crystalline silicon wafer after various pretreatment steps, including chemical solution pre-cleaning, chemical solution cleaning damage layer, chemical solution polishing, laser rough drying, or mechanical rough drying.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claim 1, wherein the crystalline silicon wafer is a crystalline silicon wafer for producing a solar cell.
The method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claim 1, wherein the chemical solution is corroded to prepare a suede surface, and an acidic chemical solution is used to etch the surface of the crystalline silicon wafer to prepare a suede surface. Or an alkaline chemical solution etches the surface of the crystalline silicon wafer to prepare a suede.
The method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claim 10, characterized in that other kinds of additives may be contained in the alkaline chemical solution and the acidic chemical solution.
A method for preparing a suede by chemical solution etching on a surface of a crystalline silicon wafer according to claims 1 and 10, wherein the chemical solution is corroded to prepare a suede surface by a groove gap chemical solution etching crystal silicon surface preparation Suede, or a horizontal continuous chemical solution to etch the surface of the crystalline silicon to prepare the suede.