CN105039006A - Cleaning agent used for solar grade silicon wafers and preparing method thereof - Google Patents

Abstract

The invention discloses a cleaning agent for solar grade silicon chips and a preparation method thereof. The cleaning agent includes the following raw materials in parts by weight: 2-5 parts of inorganic alkali, 10-20 parts of surfactant, 1-5 parts of corrosion inhibitor, 1-5 parts of complexing agent, 0.1-0.5 parts of auxiliary agent, water plus up to 100 servings. The preparation method of the cleaning agent comprises the following steps: firstly mix water and surfactant, stir at a rotating speed of 300-500 rpm, slowly add inorganic alkali several times in small amounts, continue stirring for 10-20 minutes, and finally add complexing agent , corrosion inhibitors and additives are completely dissolved by stirring to obtain the cleaning agent. The cleaning agent for solar-grade silicon wafers of the invention can effectively remove metal ions and various organic pollutants on the surface of the silicon wafers, has little damage to the silicon wafers, less cleaning foam and high cleaning efficiency.

Description

A cleaning agent for solar grade silicon wafers and preparation method thereof

technical field

The invention relates to the field of photovoltaic technology, and more specifically relates to a cleaning agent for solar-grade silicon wafers and a preparation method thereof.

Background technique

With the rapid development and wide application of crystalline silicon solar cells, high-quality photovoltaic devices with excellent performance and good stability are increasingly favored by the market. Silicon wafers are the core components of solar cells, and their surface cleanliness, surface state and other performance parameters directly affect the power generation efficiency of solar cells. After the silicon wafer has been multi-wire cut, there are various contaminations on the surface, such as organic matter, inorganic matter, particles, metal ions, etc., and the existence forms of various contaminations on the surface of the silicon wafer are also different. Therefore, what kind of cleaning method should be used? Detergent cleaning of such complex stains is essential.

At present, the silicon wafer cleaning agents on the market generally have the following problems: one is that the foam generated during the cleaning process is large, requiring multiple rinsing procedures, wasting water resources, and increasing the difficulty of subsequent sewage treatment; the other is the cleaning agent at the initial stage of cleaning The alkalinity of the silicon wafer is too strong, so that the surface of the silicon wafer has over-corrosion phenomenon, and the over-corrosion sheet appears; the third is that the removal power of metal ions is weak, especially Cu, Fe, Ni, and these metal ions are easy to diffuse from the surface of the silicon wafer to the surface of the silicon wafer. A deep energy level recombination center is formed inside; the above problems will lead to a decrease in the cleaning rate and yield of silicon wafers, and ultimately affect the photoelectric conversion efficiency. Therefore, for high-efficiency solar cells, the surface treatment of silicon wafers is very critical.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is how to effectively remove the organic matter contamination, metal ion contamination and other particle pollution generated during the processing of solar silicon wafers, and make the cleaning foam low, less rinsing process, high cleaning efficiency, and provide a Cleaning agent for solar grade silicon wafers.

(2) Technical solution

In order to solve the above-mentioned technical problems, the invention provides a cleaning agent for solar-grade silicon wafers, which includes the following raw materials in parts by weight: 2-5 parts of inorganic alkali, 10-20 parts of surfactant, corrosion inhibitor 1-5 parts, complexing agent 1-5 parts, auxiliary agent 0.1-0.5 parts, water added to 100 parts.

Preferably, the cleaning agent includes the following raw materials in parts by weight: 2.5-4 parts of inorganic base, 12-18 parts of surfactant, 1-3 parts of corrosion inhibitor, 1.5-3 parts of complexing agent, 0.2-0.4 parts of auxiliary agent parts, water was added to 100 parts.

Preferably, the inorganic base is one or two of KOH and NaOH.

Preferably, the surfactant is one or two of fatty alcohol polyoxyethylene ethers (AEO7, AEO9) and alkylphenol polyoxyethylene ethers (OP-9, OP-10).

Preferably, the corrosion inhibitor is one or more of diethanolamine, triethanolamine and ethylenediamine. The above-mentioned corrosion inhibitors are all amine organic bases, which have the ability to chelate metal ions, which can reduce the contamination of metal ions on the surface of silicon wafers after cleaning; they also have pH buffering capabilities, which can make the pH of the cleaning agent The value is kept in a stable range to prevent the inorganic alkali from over-corroding the silicon wafer, resulting in defective products such as white spots; and can effectively inhibit the foam produced by the surfactant, which can reduce the rinsing process, reduce the amount of cleaning water, and reduce sewage treatment. burden.

Preferably, the complexing agent is one or two of disodium edetate and diethylenetriaminepentaacetic acid.

Preferably, the auxiliary agent is one or more of ethanol, isopropanol and propylene glycol.

Preferably, the water is pure water with a resistivity of 18MΩ·CM. The use of pure water can avoid the pollution of metal ions such as calcium, magnesium and aluminum in the water to the silicon wafer, and improve the use efficiency of the cleaning agent.

Preferably, the cleaning agent includes the following raw materials in parts by weight: 2.5-3 parts of KOH, 12-15 parts of alkylphenol polyoxyethylene ether (OP-10), 5 parts of fatty alcohol polyoxyethylene ether (AEO-9) -8 parts, 1-2 parts of ethylenediamine, 2-3 parts of triethanolamine, 1.5-2 parts of diethylenetriaminepentaacetic acid, 1-2 parts of disodium edetate, 0.2-0.3 parts of isopropanol, Add water to 100 parts.

The raw materials used in the present invention are all commercially available.

The present invention also provides the preparation method of the cleaning agent for solar-grade silicon wafers. The method includes the following steps: firstly mix water and surfactant, and slowly add inorganic Alkali, continue to stir for 10-20 minutes, finally add complexing agent, corrosion inhibitor and additives, stir to dissolve completely, and obtain the cleaning agent. Adopting the above-mentioned preparation method can effectively avoid adverse reactions such as loss of activity of the surfactant, volatilization of auxiliary agents, and local generation of a large amount of heat by the cleaning agent during the preparation process.

(3) Beneficial effects

The cleaning agent of the present invention is applied to the high-efficiency cleaning of solar-grade silicon wafers, not only can effectively remove organic and inorganic pollution, but also can remove metal ions on the silicon surface layer, so as to ensure the electrical performance, reliability and yield of the cells prepared in the subsequent process; The invented cleaning agent has simple formula, good cleaning effect, low foam and no damage to silicon chips.

Detailed ways

Embodiments of the present invention will be further described in detail below in conjunction with examples. The following examples are used to illustrate the present invention, but should not be used to limit the scope of the present invention.

Example 1

Cleaning agent comprises the raw material of following weight portion:

The preparation method of the above-mentioned cleaning agent is as follows: firstly mix the pure water and the surfactant fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether, and slowly add KOH in small amounts several times while stirring at a speed of 400 rpm, and continue Stir for 20 minutes, and finally add complexing agent diethylenetriaminepentaacetic acid; corrosion inhibitor triethanolamine, ethylenediamine and auxiliary agent isopropanol, stir to dissolve completely, and obtain the cleaning agent.

Example 2

The preparation method of the above-mentioned cleaning agent is as follows: firstly mix the pure water and the surfactant fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether, and slowly add KOH in small amounts several times while stirring at a speed of 500 rpm, and continue Stir for 10 minutes, and finally add complexing agents diethylenetriaminepentaacetic acid and disodium ethylenediaminetetraacetate; corrosion inhibitor triethanolamine and auxiliary agents ethanol and propylene glycol, and stir to dissolve completely to obtain a cleaning agent.

Example 3

Concrete formula is as follows in the present embodiment:

Example 4

Concrete formula is as follows in the present embodiment:

Example 5

Concrete formula is as follows in the present embodiment:

The high-efficiency cleaning agent for solar-grade silicon wafers of the present invention is a water-based cleaning agent. When cleaning, take the above-mentioned prepared cleaning agent and dilute it with pure water at a mass ratio of 1:50 before use. The high-efficiency cleaning agent for solar-grade silicon wafers of the present invention is simple to operate and easy to store. The cleaning test shows that the cleaned silicon wafer has no white spots and water marks, and does not damage the performance of the silicon wafer, and the cleaning rate is greater than 99.4%.

With the present invention and two kinds of commercially available cleaning agents cleaning silicon chip, its cleaning effect is as table 1:

Table 1: Silicon Wafer Cleaning Effect

The commercially available cleaning agents in the table are commonly used cleaning agents for silicon wafers. They generally have the following problems: First, the foam generated during the cleaning process is large, requiring multiple rinsing procedures, wasting water resources, and increasing the difficulty of subsequent sewage treatment; The second is that the alkalinity of the cleaning agent at the initial stage of cleaning is too strong, which causes over-corrosion on the surface of the silicon wafer, and over-corrosion chips are prone to appear; the third is that the removal of metal ions is weak, especially the removal of Cu, Fe, and Ni ions. As can be seen from the table, the comprehensive effect of the cleaning agent of the present invention is obviously better than that of the existing cleaning agent.

The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications or equivalent replacements of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all should cover Within the scope of the claims of the present invention.

Claims (10)

1. A cleaning agent for solar grade silicon wafers, characterized in that the cleaning agent comprises the following raw materials in parts by weight: 2-5 parts of inorganic alkali, 10-20 parts of surfactant, 1-5 parts of corrosion inhibitor , 1-5 parts of complexing agent, 0.1-0.5 parts of auxiliary agent, and 100 parts of water. 2. The cleaning agent for solar-grade silicon wafer according to claim 1, characterized in that, the cleaning agent comprises the following raw materials in parts by weight: 2.5-4 parts of inorganic alkali, 12-18 parts of surfactant, 1 part of corrosion inhibitor -3 parts, 1.5-3 parts of complexing agent, 0.2-0.4 parts of auxiliary agent, and 100 parts of water. 3. The cleaning agent for solar-grade silicon wafers according to claim 1 or 2, wherein the inorganic base is one or both of KOH and NaOH. 4. The cleaning agent for solar-grade silicon chips according to claim 1 or 2, wherein said surfactant is one or more of fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether Two kinds. 5. The cleaning agent for solar-grade silicon wafers according to claim 1 or 2, wherein the corrosion inhibitor is one or more of diethanolamine, triethanolamine and ethylenediamine. 6. The cleaning agent for solar grade silicon chips according to claim 1 and 2, characterized in that, the complexing agent is a kind of disodium edetate and diethylenetriaminepentaacetic acid or Two kinds. 7. The cleaning agent for solar-grade silicon wafers according to claim 1 or 2, characterized in that, the auxiliary agent is one or more of ethanol, isopropanol and propylene glycol. 8. The cleaning agent for solar-grade silicon wafers according to any one of claims 1-7, wherein the water is pure water. 9. The cleaning agent for solar-grade silicon wafer according to any one of claims 1-8, characterized in that, the cleaning agent comprises the following raw materials in parts by weight: 2.5-3 parts of KOH, alkylphenol poly 12-15 parts of oxyethylene ether, 5-8 parts of fatty alcohol polyoxyethylene ether, 1-2 parts of ethylenediamine, 2-3 parts of triethanolamine, 1.5-2 parts of diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid 1-2 parts of disodium, 0.2-0.3 parts of isopropanol, and 100 parts of water. 10. The preparation method of the cleaning agent for solar grade silicon wafer described in any one of claims 1 to 9, it is characterized in that, the method comprises the following steps: first water and tensio-active agent are mixed, at rotating speed 300-500 Under stirring at rpm, slowly add inorganic base, continue to stir for 10-20 minutes, finally add complexing agent, corrosion inhibitor and auxiliary agent, stir to dissolve completely, and obtain the cleaning agent.