Method of making solder balls by contained paste deposition
AssigneeHewlett-Packard Company
InventorsMatthew K. Schwiebert, Donald T. Campbell, Matthew Heydinger, Robert E. Kraft, Hubert A. Vander Plas
Life of this patent
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Abstract
A solder bump is stenciled onto a substrate, providing bumped substrate at pitches below 400 microns. The solder is applied through stencil/mask and paste method; the mask, however, remains attached to the substrate during reflow. Pitches of greater than 400 microns may also be obtained through the invention. The invention further provides for generation of uniform, controllable volume metal balls.
Claims13
A method for forming solder bumps directly on a substrate having a plurality of wettable pads using solder paste and a non-wettable, photoimageable material, comprising:
- forming a thin non-wettable photoimageable mask on the substrate with the material:
- forming a plurality of apertures in the mask 10 align with the pads;
- applying solder paste to the mask such that the solder paste loads the mask apertures;
- heating the solder paste, such that the solder paste coalesces to form solder bumps on the pads:
- and
- removing the mask after formation of the solder bumps.
Dependencies are inferred from the claim text.