Lithographic resist composition for a lift-off process
AssigneeInternational Business Machines Corporation
InventorsNicholas J. Clecak, Barbara D. Grant, Carlton G. Willson
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Abstract
Lithographic resist compositions are provided which permit an improved lift-off process in which the deposition mask with apertures has the desirable negative slope or overhang. The resist composition comprises a phenolic-aldehyde resin, a photosensitizer and Meldrum's diazo, or Meldrum's acid or suitable analogs thereof as a profile modifying agent. The profile modifying agents useful in the present invention have the formula: ##STR1## wherein R.sub.1 is C.sub.1 to C.sub.20 alkyl or aryl, R.sub.2 is H, C.sub.1 to C.sub.20 alkyl or aryl, or together R.sub.1 and R.sub.2 are cycloalkyl, A is N or H.
Claims8
A lithographic resist composition for use in a lift-off process with ultra-violet light to form a mask with apertures having a negative slope comprising a phenolic-aldehyde resin, a naphthoquinone diazide sulfonic acid ester sensitizer and in admixture therewith a profile modifying agent having the formula ##STR6## wherein R.sub.1 is alkyl or aryl having up to 20 carbon atoms, R.sub.2 is H, alkyl or aryl having up to 20 carbon atoms, or together R.sub.1 and R.sub.2 are cycloalkyl and A is N or H.
A lithographic resist composition for use in a lift-off process with ultra-violet light to form a mask with apertures having a negative slope comprising a phenolic-aldehyde resin, a naphthoquinone diazide sulfonic acid ester sensitizer and in admixture therewith a profile modifying agent that is Meldrum's acid.
A lift-off process for forming a lithographic resist image comprising baking a film comprising a phenolic-aldehyde resin, a naphthoquinone diazide sulfonic acid ester sensitizer and in admixture therewith a profile modifying agent having the formula ##STR7## wherein R.sub.1 is alkyl or aryl having up to 20 carbon atoms, R.sub.2 is H, alkyl or aryl having up to 20 carbon atoms, or together R.sub.1 and R.sub.2 are cycloalkyl, and A is N or H at a temperature for a time sufficient for said profile modifying agent to form a skin at the surface of said film,
- image-wise exposing said baked film to ultraviolet light, and
- dissolving the exposed portions of said film with aqueous alkali to form a mask with apertures having a negative slope.
Dependencies are inferred from the claim text.