Process for preparing substituted 1,2-naphthoquinone-(2)-diazide-4-sulfonic acid esters and their use in a radiation-sensitive mixture

Granted: Jan 21, 1992 Filed: Nov 3, 1989

This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.