Technique for semiconductor manufacturing

A technique for semiconductor manufacturing, comprising:

• receiving a semiconductor structure having a first material and a second material, the first material having a first incubation time and the second material having a second incubation time greater than the first incubation time under a first etching chemistry;
• pretreating the semiconductor structure;
• and
• subsequent to pretreating the semiconductor structure, performing a first main etch to the semiconductor structure for a duration under the first etching chemistry.

A technique for semiconductor manufacturing, comprising:

• receiving a semiconductor structure having a first material and a second material, the first material having a first incubation time to a first etching chemistry, the second material having a second incubation time to the first etching chemistry, and the first incubation time is shorter than the second incubation time;
• performing a first main etch to the semiconductor structure for a first duration by the first etching chemistry;
• performing a pumping operation for a pumping duration after the first main etch;
• and
• performing a second main etch to the semiconductor structure for a second duration by the first etching chemistry;
• wherein the first duration is from about 1 second to about 2.5 seconds.