| 摘要 |
The present invention provides a method for removing polymer after etching a gate stack structure of high-K gate dielectric/metal gate. The method mainly comprises the following steps: 1): forming a gate stack structure of interface SiO2/high-K gate dielectric/metal gate/poly-silicon/hard mask in sequence on a silicon substrate with device isolations formed thereon; 2): forming a resist pattern by the lithography; 3): etching the gate stack structure; and 4): immersing the resultant structure of the step 3) in an etching solution to remove the polymer, wherein the etching solution consists of HF, HCl and water, the ratio of HF by volume is 0.2˜1% and the ratio of HCl by volume is 5˜15%. According to the present invention, the wet chemical etching using a mixed solution of HF and HCl is adopted and thus it is possible to completely remove the polymer remained on both sides of the gate stack and on the surface of the silicon substrate under the room temperature. According to the present invention, it is possible not only to keep a vertical etched profile of the gate stack, but also to cause no damage on the silicon substrate. The method is well compatible with the CMOS processes and is cost efficient. |
