A trench etching and filling technique for the isolation of a power IC was
investigated. This technique consists of a deep trench formation (8.5 mu m)
with positive etching using HBr/SiF4 with 45 % in He-O-2 chemistries follo
wed by filling and global planarization with a chemical mechanical polishin
g technique. This novel trench etching technique provides better surface qu
ality of 3.1 Angstrom roughness, as measured with atomic force microscopy (
AFM). The filling and the global planarization results in a lower leakage c
urrent less than InA at a supplying voltage of 400 V.