Next, as shown in FIGS. 11A and 11B, a part of the second insulating cover layer 280 and a part of the first insulating cover layer 227 are removed by dry and/or wet etching, thereby exposing the top electrode 256. In some embodiments, part of the second insulating cover layer 280 is removed, and then part of the first insulating cover layer 227 is removed. In some embodiments, one or more wet etching operation is used. In certain embodiments, a wet etching operation is performed to remove the second insulating cover layer 280 and a dry etching operation is performed to remove first insulating cover layer 227. As set forth above, the second insulating cover layer 280 is made at a higher temperature than the first insulating cover layer 227, and thus the second insulating cover layer 280 is a “hard” layer in a dry etching operation. Accordingly, it is advantageous to use a wet etching to remove the second insulating cover layer 280. In contrast, the first insulating cover layer is made at a low temperature and thus is a “soft” layer in a dry etching operation. Thus, a dry etching operation can be utilized to remove the first insulating cover layer 227 with suppressing damage on the top electrode 256. In other embodiments, a wet etching operation is also performed to remove the first insulating cover layer 227. By using wet etching, it is possible to suppress damage to the MTJ film stack 255.