US 5,211,328 AGranted

Method of applying solder

AssigneeInternational Business Machines Corporation

InventorsJoseph G. Ameen, Joseph Funari, Ronald J. Moore

Life of this patent

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Abstract

A method of precisely depositing accurately defined quantities of solder onto high density circuit patterns on a substrate without use of a solder mask or the like wherein solder paste is originally deposited within a precisely defined transfer member (e.g., graphite block having holes drilled therein), the transfer member then being aligned relative to the respective circuitry such that when both block and substrate are heated, solder flow and deposition will occur without the use of a solder mask or the like. Following deposition, a second circuit member (e.g., flexible circuit) may be electrically coupled to the substrate's conductors, the deposited solder providing the coupling medium. Hydrogen gas may be used during the heating of the paste and also during the soldering of the flexible circuit to the substrate.

Claims20

Dependent claims

A method of applying solder to metallic sites on a substrate, said method comprising:

providing a transfer member having a plurality of holes therein, selected ones of said holes having a predetermined volume;
substantially filling said selected ones of said holes with solder paste;
positioning said transfer member having said selected ones of said holes substantially filled with said solder paste in aligned orientation relative to a substrate having a plurality of metallic sites thereon such that said selected ones of said holes having said solder paste therein are aligned with said metallic sites;
heating said transfer member to a predetermined temperature to cause said solder paste within said holes to become molten and flow onto said metallic sites;
and
cooling said flowed solder on said metallic sites such that said solder solidifies, said method being accomplished without the use of a solder mask or the like.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/886,895Filed 22 May 1992
Granted: 18 May 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

B23K 1/20
Soldering, e.g. brazing, or unsoldering: preliminary treatment of work or areas to be soldered, e.g. in respect of a galvanic coating
B23K 3/06
Tools, devices or special appurtenances for soldering, e.g. brazing, or unsoldering, not specially adapted for particular methods: solder feeding…
H05K 3/3485
Application of solder: application of solder paste, slurry or powder
H10W 70/099
Package substrates; Interposers; Redistribution layers [RDL]: connecting interconnections to insulating or insulated package substrates,…