The effect of wet chemical treatment on the magnetic tunneling junction (MTJ) was examined. The tunneling magneto-resistance (TMR) increased and the resistance of anti-parallel state and parallel state decreased when a wet cleaning treatment was carried out after a reactive ion etching process. Furthermore, the exfoliation between the capping layer and Inter layer Dielectric (ILD) was prevented. Presumably, these were due to the elimination of the damaged layer and the residues. This investigation showed that the wet treatment after the MTJ patterning using RIE process could improve the MTJ properties without degradation of Hc, such as TMR and Rlow.