Etching liquid for forming texture

Abstract

The present invention is capable of uniformly forming a stably good texture on a wafer surface by the use of an etching liquid that is composed of an aqueous solution containing (A) an alkaline component and (B) a phosphonic acid derivative or a salt thereof. The present invention provides an etching liquid for forming a texture on a silicon wafer, from which an additive component does not volatilize in the working temperature range of 60-95 DEG C, and which is applicable to both wafers cut by loose abrasive and wafers cut by bonded abrasive.

Description

technical field [0001] The present invention relates to an etchant for forming a relief structure called a texture on the surface of a silicon substrate. Background technique [0002] The crystalline silicon substrate used for solar cells is given a surface structure treatment called texture treatment for reducing the light reflectance on the substrate surface to reduce the light reflectance on the substrate surface so as to ensure Efficient light absorption is safe and efficient. [0003] Hitherto, a method of impregnating a silicon substrate with an alkaline solution of sodium hydroxide, potassium hydroxide, etc. to form a pyramid-like texture structure has been used, and it is known that by using any other than alkaline components in the etching solution, Additive to form a more uniform pyramid-like texture. [0004] As such a texture forming etchant, for example, as described in Patent Document 1, an aqueous solution of sodium hydroxide or potassium hydroxide to which ...

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Problems solved by technology

Therefore, there is a problem that the etching solution used in the existing loose abrasive system cannot be directly used in the fixed abrasive system as it is

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