Abstract of the Disclosure

A method of forming mounds of solder on integrated circuit chips having lands thereon comprising masking the surface of the chips so as to expose only the land and the area immediately thereround, evaporating a layer of solder in the mask and subsequently heating the solder above its melting point whereby the solder de-wets the area around the lands and contracts to form solder mounds on the lands.

• Figure 1 shows a cut-away side view of an integrated circuit chip with a ball limiting land formed on one surface thereof.
• Figure 2 shows the same land and chip after a layer of solder has been evaporated thereon through a metal mask.
• Figure 3 shows the finished solder mound after the originally evaporated layer has been re-melted to de-wet the ceramic.
• Figures 4a and 4b illustrate how different sized solder mounds can be formed by controlling the diameters of the evaporated solder circles.
• Figure 5 shows a circuit chip provided with both active and passive solder mounds assembled to a mounting board.

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