Etching defects on KOH etched silicon-implementation of silicon bench technology for low cost packaging

In this paper we report our experimental results about etching defects and microscopic surface roughness on potassium hydroxide (KOH) etched [100] silicon. We have studied the formation and morphology of etch hillock defects during the anisotropic etching. The morphology of etch hillocks depends on process condition. Our measurements and calculations reveal that the pyramidal shaped hillocks are bounded by {567} and {313} planes after period of etching in 30% wt and 45% wt KOH solutions respectively. Our experimental results indicated that hillock defect density is correlated with low etchant concentration and high etch temperature. The activation energy for defect formation is 1.2 eV, considerably higher than the energy associated with silicon removal. Examination of defects by electron microscopy suggests that a regrowth process may be involved in defect formation.<>