Abstract: Inductively coupled plasma（ICP） dry etching of InP was performed using C_l2/CH₄/N₂.The effects of RF power,ICP power,Process pressure,the flow rate are thoroughly discussed.By adjusting etching parameters,vertical sidewall and smooth surface can be obtained.The etch rate is 841 nm/min,and the selectivity ratio over SiO₂ is estimated to be higher than 15:1.