The citric acid‐hydrogen peroxide‐water system has been developed for preferential etching of through photoresist masks. Etching rates depend strongly on the composition of the solution and on the crystal orientation of , with the rates in the order (111)B > (100) > (111)A. Flat‐bottomed holes were obtained for all compositions of the solutions. The solution does not erode photoresist masks, thereby providing preferential etching of through such masks.
No takes yet. Share an insight, caveat, or question.
Otsubo et al. (1976) studied this question.