Method for fabricating semiconductor device

1. A method for fabricating semiconductor device, comprising:

providing a substrate;

forming a first material layer on the substrate;

forming a stop layer on the first material layer;

forming a second material layer on the stop layer;

performing a chemical mechanical polishing (CMP) process to remove part of the second material layer;

performing a first etching process to remove the remaining second material layer; and

performing a second etching process to remove the stop layer for forming a gate layer.

2. The method of claim 1 , wherein the first etching process comprises an anisotropic etching process.

3. The method of claim 1 , wherein the second etching process comprises an anisotropic etching process.