Semiconductor device and manufacturing method thereof

A method for manufacturing a semiconductor device, comprising steps of:

• forming a sacrifice layer on an insulating surface;
• forming a structural layer over the sacrifice layer so that a first part of the sacrifice layer is not overlapped with the structural layer and a second part of the sacrifice layer is overlapped with the structural layer by a first etching;
• removing the first part of the sacrifice layer by anisotropic etching so that the insulating surface is exposed whereby the second part of the sacrifice layer remains;
• removing the second part of the sacrifice layer by first isotropic etching whereby a portion of the second part of the sacrifice layer remains;
• and
• removing the portion of the second part of the sacrifice layer by second isotropic etching.

A method for manufacturing a semiconductor device, comprising steps of:

• forming a protection layer having an insulating property;
• forming a first conductive layer over the protection layer;
• forming a sacrifice layer over the first conductive layer;
• forming a second conductive layer over the sacrifice layer;
• forming a structural layer over the second conductive layer so that the structural layer is over the sacrifice layer and is in contact with the first conductive layer;
• removing a first part of the sacrifice layer that is not overlapped with the structural layer by anisotropic etching whereby a second part of the sacrifice layer that is overlapped with the structural layer remains;
• and
• removing the second part of the sacrifice layer by isotropic etching.