The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 1994
Filed:
Apr. 12, 1993
Phillip D Isaacs, Rochester, MN (US);
Gregg A Knotts, Rochester, MN (US);
Miles F Swain, Hayfield, MN (US);
Burton A Towne, Austin, MN (US);
International Business Machines Corp., Armonk, NY (US);
Abstract
A technique for filling hollow, plated-through-hole vias in multi-layer printed circuit substrates with solder and then joining the solder filled via with a solder ball on a solder ball connectable electronic module is disclosed. The filling of the vias is accomplished by depositing solder paste on one end of the hollow via and reflowing the solder particles within the solder paste to at least partially fill the PTH via. The depositing of the solder paste and the reflowing operations may be repeated until such time as the via is substantially completely filled with solid solder. The importance of the prefilling of the vias with solder is that the reflowing operation of solder balls or solder paste when joining the multi-layer printed circuit board to the electronic module, will prevent undue wicking or pulling of molten solder from the electrical connection into the PTH via, thereby preventing the formation of solder starved or unreliable electrical connections.