Microtrench/oxide island reduction with electron beam irradiation in high aspect ratio oxide etching
Abstract
During high aspect ratio oxide etching, the feature surface charges up and deflects the subsequent ion trajectories to the sidewalls due to local electric field, which results in microtrenching at the feature edges. At the etch end point, the microtrench reaches the conducting underlayer, which does not accumulate charge, and an oxide island remains at the center if no overetching is used. An electron beam source [1] is developed to neutralize the positive charge buildup at the feature bottom during etching. SEM images of the etch profiles show that the microtrench/oxide island formation is reduced with the electron beam irradiation. The electric field and ion trajectories within an etch feature are calculated, indicating that the reduction of the microtrench/oxide island formation is achieved by electron beam charge neutralization te at the feature bottom. [1] D. M. Shaw, M. Watanabe, G. J. Collins, and H. Sugai, Jpn. J. Appl. Phys. 38, 87 (1999).
- Publication:
-
APS Annual Gaseous Electronics Meeting Abstracts
- Pub Date:
- October 2001
- Bibcode:
- 2001APS..GECJWP066W