Method for STI-top rounding control

  • US 6,225,187 B1
  • Filed: 04/01/1999
  • Issued: 05/01/2001
  • Est. Priority Date: 02/12/1999
  • Status: Expired due to Term
First Claim
Patent Images

1. A method for STI top-rounding control, the steps comprising:

  • (a) providing a semiconductor substrate;

    (b) forming an oxide layer on the substrate;

    (c) forming a hard mask on the oxide layer;

    (d) forming a photoresist pattern with an opening exposing the hard mask at a predetermined STI trench region on the hard mask;

    (e) etching the exposed hard mask and the underlying oxide layer within the opening in sequence, and continuously over-etching to remove part of the semiconductor substrate to form a window lower than the surface of the oxide layer wherein corners of the window are round; and

    (f) using the photoresist pattern and the hard mask as an etching mask, removing part of the exposed semiconductor substrate within the window to form an STI trench.

View all claims

    Thank you for your feedback