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Process for Etching Minimum-Size Tapered Vias in Polymer Films Disclosure Number: IPCOM000058642D
Original Publication Date: 1988-Nov-01
Included in the Prior Art Database: 2005-Feb-15

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Geffken, RM [+details]


A technique is shown for combining a silylated resist image and a deep ultraviolet resist underlayer to achieve a practical means for producing minimum lithographic images in a thick erodable masking layer over an organic insulator. Current via etch technology relies on reactive ion etch (RIE) of a thick reflowed resist film to achieve tapered vias. The thickness of the resist film is generally 2.5 x the thickness of the polymer thickness due to variations in polymer thickness, thinning of the resist over topological features and a rapid erosion of the resist during the dry etch process. The minimum via size that can be printed and reliably reflowed in resist of this thickness is about 3 um. This is far greater than the 1 um minimum that is achievable with state-of-the-art photo groundrules.