Nonbleachable absorbance

One approach to minimize these problems is the image-reversal process described in Section 2.2 (28, 29). Another approach has been to increase the nonbleachable absorbance of the resist by adding a dye (30). This ap-... 

When it was observed that the DNQ/novolac resists in use at the time became more transparent on exposure (i.e., they bleached). Dill used this change in optical absorbance as a way of monitoring the kinetics of exposure. He developed a first-order model of exposure consisting of three parameters A, B, and C, now called the Dill model, which accurately fit the experimental measurement results of the transmittance of a resist coating on an optically matched glass wafer as a function of exposure dose. The Dill parameters A, B, and C, describe bleachable absorbance, nonbleachable absorbance, and exposure rate constant, respectively." ... 

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