Application of Buffer Oxide Etching Fluid in Wet Etching Process of Trench Structure
Aiming at the application of oxide etching fluid(BOE)in trench structure wet etching process,the influencing factors of three kinds of wet etching processes,namely,single sheet cleaning process,trough cleaning process and beaker experiment were investigated,such as chuck speed,chemical flow rate,pre-washing and surfactant use.The results show that in the beaker experiment,the addition of surfactants significantly reduces the etching rate.The etching rate of the upper,middle and lower parts of the trench is about 60Å/min lower than that of the single sheet process and the trough cleaning process.In the process of single chip cleaning,increasing the chuck speed or BOE flow rate can improve the etching rate of silicon oxide.Using deionized water to pre-wash the wafer surface is conducive to the uniformity of trench structure etching.In the trough cleaning process,the more suitable circulation flow is 13 L/min,which can provide a reference for the etching process of BOE in the high aspect ratio structure.
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