ICP ( Inductively Coup led Plasma) etching technique has been app lied to HgCdTe providing significant benefits such as high uniformity, low damage and anisotrop ic profile, etc. We have studied the dependence of surface profile, post-etch composition, formation of polymer on the effect of ICP parameters ( ICP power, gas ratio, chamber pressure) by usingmicro regional XPS and SEM ( scanning electron microscopy). We have found that methane can react with photoresist ( PR) which is used asmask, the productmay be C6H5 (CH3 ). The product can’t be pumped out if the chamber p ressure is high, then itwill be left on the samp le surface forming so-called polymer. Otherwise if the chamber pressure is low, the product is pumped away the chamber in time, and there is no polymer on the surface. H2 can reactwith PR, and the products are several organic compounds with carbon. Under certain condition, methane can reactswith SiO2 or high vacuum grease, generatingMylar Polyster.