US 6,982,138 B2
Method of controlling removal of photoresist in openings of a photoresist mask
Arkady Nikitin, Yonkers, N.Y. (US); and Dmitriy Yeremin, Dobbs Ferry, N.Y. (US)
Assigned to General Phosphorix, LLC, Ardsley, N.Y. (US)
Filed on Aug. 04, 2003, as Appl. No. 10/633,602.
Prior Publication US 2005/0032004 A1, Feb. 10, 2005
Int. Cl. G03F 9/00 (2006.01)
U.S. Cl. 430—30 9 Claims
 
1. A method of making a conclusion about a presence or absence of photoresist in openings of a photoresist mask, comprising the steps of obtaining in a scanning electron microscope a video signal of a bottom of an opening of a photoresist mask; and comparing values of the video signal in different points of an image which contains the opening, wherein said comparing includes selecting a portion of a field of vision outside of an image of the opening; determining a mean value of the video signal and a mean square amplitude of noise on the selected portion; subdividing the image of the bottom of the opening into fragments; repeating calculations of a mean signal in each fragment; calculating paired differences of average values of the signal; selecting those paired differences which exceed a threshold; and making a conclusion about a presence or absence of non-removed photoresist with determination of borders of the islands.