Positive photoresist composition with cresol-formaldehyde novolak resins
AssigneePhilip A. Hunt Chemical Corporation
InventorMedhat A. Toukhy
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Abstract
Cresol-formaldehyde novolak resins made from a mixture containing meta- and paracresol or ortho-, meta- and paracresol in a ratio selected from a given range for use in fast positive photoresist compositions together with one or more sensitizing compounds. When dissolved in a mixture of organic solvents, the photoresist compositions are suitable for application as a thin coating to a substrate. After the coating has been dried, the coated substrate can be exposed to image-wise modulated actinic radiation and developed in alkaline solution, yielding a relief pattern of resist on substrate useful for a number of applications.
Claims9
A positive photoresist composition comprising and ester condensation product of
- (a) a naphthoquinone diazide sulfonyl compound, and
- (b) a cresol-formaldehyde novolak resin produced by condensing a mixture of cresol isomers with formaldehyde in the presence of acid, said mixture of cresols consisting essentially of percentages by weight of ortho-, meta- and paracresol whose values are within the area bounded by quadrilateral ABCD in FIG. 1, said resin having a softening point within the range of 110.degree. to 145.degree. C. wherein from about 4% to about 25% of hydroxy groups of the novolak resin are esterified.
Dependencies are inferred from the claim text.