International Business Machines Corporation

Ian M Croll

Lubomyr Taras Romankiw

Eugene E Castellani

Aloysius T Pfeiffer

A method is disclosed for the production of thick and smooth layers of photoresist on the order of 2-15 microns thick. The substrate is flooded with resist as in the standard spin resist method, but instead of following the flooding step with spinning as usual, the second step is to provide a drying time for the flooded resist. Then at the end of the measured drying time, the resist is spun as usual. This can be used to produce fine line closely spaced circuitry in which the thickness of the lines in proportion to their width, or their aspect ratio, is large. Aspect ratios greater than 0.4 and as high as 1.5 are contemplated by the invention.

Fine-line circuit fabrication and photoresist application therefor

Resist is applied to a surface with a syringe, or other suitable dropper, equipped with a millipore filter to remove contaminants. The surface is completely flooded with resist. Resist is allowed to remain on the surface of the evaporated metal for a period of time prior to spin coating. Allowing resist to remain on the surface prior to coating produces a uniform film. For a 2 micron thick uniform resist coating, a minimum of 15 seconds is allowed prior to spinning while in the case of a 4 micron thick resist coating a much longer period is allowed. For the application of a 2 micron film, the resist material after partial drying for approximately 15 seconds is spun at 2000 rpm for 30 seconds. In order to apply a 5 micron thick resist film, resist is spun at 2000 rpm for 30 seconds after partial drying for approximately 10 minutes.

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Pleasantville, NY, United States of America

Ian M Croll