John H Reece

US Patent:

51976552, Mar 30, 1993

Filed:

Jun 5, 1992

Appl. No.:

7/894491

Inventors:

Arthur L. Leerssen - Austin TX
Everitt W. Mace - Hutto TX
Issa S. Mahmoud - Apalachin NY
Charles T. Randolph - Vestal NY
John Reece - Endicott NY
Gaston G. Settle - Georgetown TX
Phong T. Truong - Round Rock TX
Srini V. Vasan - Austin TX

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H01L 2158

US Classification:

228254

Abstract:

Methods and apparatus are provided for applying solder in precise amounts to fine pitch leads such as those suitable for direct chip attachment (DCA) or flip-chip applications by using a heated platen to apply pressure to solder overlaying a plurality of lands on circuitized substrate. In one embodiment paste solder screened through a mask having apertures each corresponding to a plurality of land locations. In another embodiment, a web of solder foil is accurately positioned over a plurality of fine pitch lands. In each embodiment, a heated platen includes at least one active element corresponding in size and shape to the area having a plurality of fine pitch lands. A third embodiment includes individual platens for lands to which solder is to be applied.