Small, Thick Solder Pad Formation
Original Publication Date: 1985-May-01
Included in the Prior Art Database: 2005-Feb-18
Solder joining techniques are widely used in micro-electronic circuitry, the solder pads being conventionally formed by evaporating through a metal mask. The size of the solder pad is limited by the hole size that can be etched in the metal mask and by the solder thickness required. In general, the metal mask is thicker than the solder thickness, and the smallest hole size is comparable to or larger than the mask thickness. In order to achieve small-size, thick solder film pads, a thick organic film-patterned metal layer is used. Figs. 1-5 show the formation of a small, thick solder pad. The substrate 10 has a layer 12 of thick organic film (such as RISTON*) thereon. A metal film 14 is vacuum deposited to a thickness of about 10,000 angstroms.