Siemens Aktiengesellschaft

Kurt Plehnert

Horst Pachonik

Alfred Pichler

Gerhard Mitterhummer

Gerhard Beil

In the fabrication of micro-electronic circuits, it is often necessary to arrange a number of patterned surfaces be well insulated from each other. At the same time, however, the pattern edges of the layer to be overlaid must present a defined slope angle of between the range of forty to sixty degrees, for example. The invention solves this problem through a two stage coating process in which a polymer is first applied which coats the edges and is then coated with a photoresist having good leveling properties.

Electrical isolation and leveling of patterned surfaces

A method and apparatus for producing micro-wiring arrangements on a flexible, insulating carrier band for the purpose of contacting semiconductors characterized by providing a carrier band having at least one opening therein for subsequently receiving an assembly, a thin metal band bonded onto one side of the carrier band with a first layer of photosensitive varnish covering the metal layer and a second layer of photosensitive varnish covering the opposite side of the carrier band and any metal exposed through the openings therein, and after exposing the first layer with the desired pattern, treating the layer to uncover portions of the metal layer by floating the band across a surface of a treating bath such as a developing bath to contact the first layer without contacting the second layer with the developing material and creating a flow in the bath directed generally toward the first layer to contact the first layer and to thereby cause developing of the first layer to uncover portions of the metal layer. The method further includes using a similar device to remove the remaining portion of the first layer in a layer removing bath by floating the band across the surface of the layer removing bath without contacting the second layer with the liquid of the layer removing bath and while floating the band across the bath producing or creating a flow in the bath to contact the entire surface of the first layer to ensure removal thereof.

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Pullach, Germany

Kurt Plehnert