Determination of the Exposure Dosage for Positive Photoresists
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
This method involves the use of high pressure liquid chromatography to isolate the photoactive component of the photoresist in both its unexposed and exposed forms. This quantitative technique can pinpoint the amount of exposure necessary to obtain complete pattern development, providing a simple and fast analytical method which replaces subjective trial and error experiments. In general, positive resists contain various organic solvents, a phenolic resin, and a photoactive component. Upon exposure, the photoactive component is converted into an aqueous soluble material. This reaction sequence, ignoring the ketene intermediate, is shown in the figure. Of main importance is the drastic solubility difference between the unexposed and exposed photoactive component.