Abstract: IrMn top spin valves, with a structure of Ta/NiFe/CoFe/Cu/CoFe/IrMn/Ta, were deposited on glass and silicon substrate by high vacuum DC magnetron sputtering. The spin valves have a MR ratio of 9.12% and a coercivity of 1.04×（10³/4π）A/m after the optimizing the structure parameters and the fabrication conditions. The effects of the thickness （＜ 6nm） of Ta buffer layer on the properties of the spin valves were investigated. The results show that the MR ratio reaches a maximum at 3nm Ta buffer layer, and the coercivity decreases with the increase of Ta thickness. The exchange bias field is enhanced from 180 ×（10³/4ir）A/m to about 600 ×（10³/4π）A/m using SAF structure （CoFe/Cu/CoFe） to replace the CoFe pinned layer. The coercivity is reduced by 33% using a 2 min RIE process, which has a negligible effect on the MR.