Method of making high density solder bumps and a substrate socket for high density solder bumps

Abstract

A method of forming solder bumps includes the steps of applying a thick layer of solder resist to a substrate. The resist is selectively removed to provide wells at solder pads on the substrate. The solder paste is applied to the substrate in the wells. The solder paste is reflowed to form solder bumps on the pads. A socket for a solder bumped member is obtained by first providing a substrate having metalized pads corresponding to the solder bumps of the member. A thick layer of photo definable solder resist is applied to the substrate. The resist is selectively removed to provide wells at the metalized pads of the substrate. Solder paste is then deposited in the wells. The solder bumped member can then be positioned so that the solder bumps are located in the wells. The solder paste is reflowed to bond to the solder bumps and the metalized pads. The solder paste can be selected to have a lower melting temperature than the solder bumps. By reflowing the solder paste at a temperature lower than the melting temperature of the solder bumps, the paste can wet to and blend with the solder bumps while not causing the solder bumps to reflow.

Dependencies are inferred from the claim text.