阅读说明：本技术 一种金属离子辅助非硝酸抛光方法 (Metal ion-assisted non-nitric acid polishing method ) 是由 常洪进 刘宇琛 万鹏 侯成成 管自生 于 2019-11-28 设计创作，主要内容包括：本发明涉及单晶硅太阳能电池技术领域,且公开了一种金属离子辅助非硝酸抛光方法,包括以下步骤：S1：配置抛光液：依次将硝酸银溶液1.5ml/L-5ml/L,有机酸0.1-5％,氟氢化铵0.5-5％,双氧水10-40％以及其他组分溶解到余量的去离子水中,混合均匀；S2：加热抛光：将S1中得到的抛光液加热到55～70℃,将单晶制绒片置入抛光液中进行抛光,抛光时间为90-360s以内；S3：清洗：将S2中抛光完毕的单晶制绒片进行清洗。该金属离子辅助非硝酸抛光方法,能够解决目前反射率低,稳定性差,消耗量大的问题。(The invention relates to the technical field of monocrystalline silicon solar cells, and discloses a metal ion-assisted non-nitric acid polishing method, which comprises the following steps: s1: preparing a polishing solution: dissolving 1.5-5 ml/L silver nitrate solution, 0.1-5% organic acid, 0.5-5% ammonium bifluoride, 10-40% hydrogen peroxide and other components in the balance of deionized water in sequence, and mixing uniformly; s2: heating and polishing: heating the polishing solution obtained in the step S1 to 55-70 ℃, and putting the single crystal texturing sheet into the polishing solution for polishing within 90-360 seconds; s3: cleaning: and cleaning the polished monocrystal flocking sheet in the step S2. The metal ion-assisted non-nitric acid polishing method can solve the problems of low reflectivity, poor stability and high consumption at present.)

1. A metal ion-assisted non-nitric acid polishing method is characterized by comprising the following steps:

s1: preparing a polishing solution: dissolving 1.5-5 ml/L silver nitrate solution, 0.1-5% organic acid, 0.5-5% ammonium bifluoride, 10-40% hydrogen peroxide and other components in the balance of deionized water in sequence, and mixing uniformly;

s2: heating and polishing: heating the polishing solution obtained in the step S1 to 55-70 ℃, and putting the single crystal texturing sheet into the polishing solution for polishing within 90-360 seconds;

s3: cleaning: and cleaning the polished monocrystal flocking sheet in the step S2.

2. The metal ion-assisted non-nitric polishing method of claim 1, wherein: the organic acids include citric acid, acetic acid, glycolic acid, malic acid, lactic acid, and oxalic acid.

3. The metal ion-assisted non-nitric polishing method of claim 2, wherein: the polishing solution comprises the following components in percentage by mass: citric acid: 0.1-1 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

4. The metal ion-assisted non-nitric polishing method of claim 2, wherein: the polishing solution comprises the following components in percentage by mass: acetic acid: 0.5-5 percent of ammonium bifluoride, 0.5-5 percent of hydrogen peroxide, 10-40 percent of hydrogen peroxide, silver nitrate with the concentration of Ag + maintained at 1.5-5 ml/L and the balance of deionized water.

5. The metal ion-assisted non-nitric polishing method of claim 1, wherein: the polishing solution comprises the following components in percentage by mass: glycolic acid: 0.1-1 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

6. The metal ion-assisted non-nitric polishing method of claim 1, wherein: the polishing solution comprises the following components in percentage by mass: malic acid: 0.1-1 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

7. The metal ion-assisted non-nitric polishing method of claim 2, wherein: the polishing solution comprises the following components in percentage by mass: lactic acid: 0.5-5 percent of ammonium bifluoride, 0.5-5 percent of hydrogen peroxide, 10-40 percent of hydrogen peroxide, silver nitrate with the concentration of Ag + maintained at 1.5-5 ml/L and the balance of deionized water.

8. The metal ion-assisted non-nitric polishing method of claim 2, wherein: the polishing solution comprises the following components in percentage by mass: oxalic acid: 0.5-3 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

Technical Field

The invention relates to the technical field of monocrystalline silicon solar cells, in particular to a metal ion-assisted non-nitric acid polishing method.

Background

The core of the local contact back Passivation (PERC) solar cell is that the back of a silicon wafer is covered by aluminum oxide and silicon nitride to play the roles of passivating the surface and improving long-wave response, thereby improving the conversion efficiency of the cell. The uniformity of the reflectivity of the etched silicon wafer determines the uniformity of the back passivation coating film and also determines the uniformity of the laser aperture ratio and size, so that the etching plays a significant role in the whole production process of the PERC battery.

A chain-type hydrofluoric acid/nitric acid mixed acid back polishing process is mainly used at present, and comprises the steps of floating a ① silicon wafer on etching liquid composed of hydrofluoric acid/nitric acid to remove phosphosilicate glass (PSG) on the back and the edge, polishing the back, removing porous silicon and acid liquid for neutralizing the surface of the silicon wafer through NaOH aqueous solution ②, and removing phosphosilicate glass on the front of the silicon wafer through hydrofluoric acid aqueous solution ③.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a metal ion-assisted non-nitric acid polishing method, which has the advantage of improving the reflecting surface and solves the problems of low reflectivity, poor stability and high consumption at present.

(II) technical scheme

In order to realize the purpose of improving the reflecting surface, the invention provides the following technical scheme: a metal ion-assisted non-nitric acid polishing method comprises the following steps:

s1: preparing a polishing solution: dissolving 1.5-5 ml/L silver nitrate solution, 0.1-5% organic acid, 0.5-5% ammonium bifluoride, 10-40% hydrogen peroxide and other components in the balance of deionized water in sequence, and mixing uniformly;

s2: heating and polishing: heating the polishing solution obtained in the step S1 to 55-70 ℃, and putting the single crystal texturing sheet into the polishing solution for polishing within 90-360 seconds;

s3: cleaning: and cleaning the polished monocrystal flocking sheet in the step S2.

Preferably, the organic acids include citric acid, acetic acid, glycolic acid, malic acid, lactic acid and oxalic acid.

Preferably, the polishing solution comprises the following components in percentage by mass: citric acid: 0.1-1 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

Preferably, the polishing solution comprises the following components in percentage by mass: acetic acid: 0.5-5 percent of ammonium bifluoride, 0.5-5 percent of hydrogen peroxide, 10-40 percent of hydrogen peroxide, silver nitrate with the concentration of Ag + maintained at 1.5-5 ml/L and the balance of deionized water.

Preferably, the polishing solution comprises the following components in percentage by mass: glycolic acid: 0.1-1 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

Preferably, the polishing solution comprises the following components in percentage by mass: malic acid: 0.1-1 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

Preferably, the polishing solution comprises the following components in percentage by mass: lactic acid: 0.5-5 percent of ammonium bifluoride, 0.5-5 percent of hydrogen peroxide, 10-40 percent of hydrogen peroxide, silver nitrate with the concentration of Ag + maintained at 1.5-5 ml/L and the balance of deionized water.

Preferably, the polishing solution comprises the following components in percentage by mass: oxalic acid: 0.5-3 percent of silver nitrate, 0.5-5 percent of ammonium bifluoride, 10-40 percent of hydrogen peroxide, 1.5-5 ml/L of silver nitrate with Ag + concentration and the balance of deionized water.

(III) advantageous effects

Compared with the prior art, the invention provides a metal ion-assisted non-nitric acid polishing method, which has the following beneficial effects:

according to the metal ion-assisted non-nitric acid polishing method, the components used by the polishing solution are safe and stable, pollution is not easily caused, the reflection capacity of the surface of a silicon wafer can be obviously improved on the premise of controlling the weight reduction of the silicon wafer, appropriate reaction time can be obtained, the single crystal texturing sheet obtained after polishing is microscopically uniform and flatter, and meanwhile, the consumption of the polishing solution is low.

Drawings

FIG. 1 is a schematic view of a textured microstructure of a single-crystal texturing sheet in a metal ion-assisted non-nitric acid polishing method according to the present invention before polishing;

FIG. 2 is a schematic view of a textured microstructure of a single-crystal textured sheet polished under different organic acids in a metal ion-assisted non-nitric acid polishing method provided by the invention;

FIG. 3 is a comparison graph of wavelength-reflectance curves before and after polishing of a single-crystal texturing sheet in a stoichiometric ratio in a metal ion-assisted non-nitric acid polishing method provided by the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.