Method for removing micro-damage layer from crystalline silicon surface after RIE (Reactive Ion Etching) flocking

Abstract

The invention relates to the field of surface treatment method for silicon chips, in particular to a method for removing a micro-damage layer from a crystalline silicon surface after RIE (Reactive Ion Etching) flocking. The method comprises the following steps of: cleaning an RIE-treated silicon chip with a mixed acid liquid of HNO3 and HF diluted with CH3COOH, wherein the volume percentage of the CH3COOH is 0.1-10 percent, and the volume percentage of the HNO3 is 85.0-99.5 percent; and thermally treating in a N2 atmosphere for 1-30 minutes at the temperature of 200 to 400 DEG C. Compared with an ordinary damage removing process, the invention has the advantages that: a non-aqueous acid etching liquid is adopted, and the ratio of HNO3 in an etching solution is increased simultaneously, sothat the etching rate is moderate, the process is easy to control, the etching uniformity is high, and the microscopic structure of an RIE flocked surface is kept; the method is suitable for industrial production; and a subsequent thermal treatment process is combined, so that the micro-damage layer on the surface of the silicon chip can be further reduced, and chemical residues are removed effectively.

Description

technical field [0001] The invention relates to the field of silicon chip surface treatment methods, in particular to a method for removing a micro-damage layer on the surface of crystalline silicon after RIE texturing. Background technique [0002] At present, in the industrial production of solar crystalline silicon, wet etching is generally used to prepare the textured surface, and at the same time remove a part of the cutting damage layer on the surface of the silicon wafer. Using the RIE method to prepare the textured surface will introduce more surface damage than the ordinary acid textured or alkali textured surface. The surface damage and etching methods commonly used in crystalline silicon RIE textured surfaces mainly include: 1. NH4OH: H2O2: DI(1 : 1:5) solution is RCA2; 2. The aqueous solution of low-concentration strong alkaline chemicals (NaOH, KOH, etc.); 3. The aqueous solution of low-concentration strong acidic chemicals (HF+HNO3), etc. [0003] The above th...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is: to solve the problem of the surface damage layer introduced by the RIE texturing method, to improve the uniformity of etching by adopting a new damage-removing etching method, and to effectively remove the chemical residues on the surface of the silicon wafer. while retaining the microstructure of the RIE suede