International Business Machines Corporation

Daniel S Niedrich

Voya Rista Markovich

Eric P Dibble

Richard Stuart Zarr

Gary Paul Vlasak

Steven L Hanakovic

Richard C Senger

Process is described for applying large quantities of solder to small areas, such as the lands in a high density card, to which it is intended to surface mount electronic devices or directly attach circuitized chips. The land area is temporarily extended by depositing a relatively thin layer of metal beyond the perimeter of the land, wave soldering to deposit excess solder on the extended land region, and reflow, whereby the thin layer of metal dissolves into the solder, causing the solder to retract to the dimensions of the original land. Because the volume of solder is increased, the strength and reliability of the solder joint is greatly improved.

Applying solder to high density substrates

Low melting temperature copper-containing solders are disclosed for soldering and rework on copper surfaces. The amount of copper required in the solder in order to inhibit dissolution of the copper surface to be soldered has been found to be dopant level, below the binary tin-copper eutectic point.

Copper doped low melt solder for component assembly and rework

Growing community of inventors

Apalachin, NY, United States of America

Daniel S Niedrich