Ball placement method and apparatus for forming a ball grid arra

Details Ball placement method and apparatus for forming a ball grid arra Ball placement method and apparatus for forming a ball grid arra

1997-02-21

1999-08-10

Ryan, Patrick

Metal fusion bonding

Process

With disassembling of bonded joint

228 41, 228246, 228254, B23K 1018, B23K 100, B23K 3102

Patent

active

059345454

ABSTRACT:
A method and apparatus allow securing of balls to ball grid array electronic components. A component having a surface with rows and columns of electrical contact solder pads is removed from a printed circuit board for rework. Excess solder is removed from the solder pads and the surface is pressed against a stencil having a pattern of holes corresponding to the component contact pad pattern. Each of the holes is filled with a solder ball. The assembly is heated to melt the at least the solder pads. Where lower melting solder balls are used, the pads and balls both melt. Where high melting temperature solder balls are used, only the solder pads melt. The assembly is cooled to solidify melted solder, the stencil is removed, the component is cleaned and is ready for reuse. Preferably, the stencil is formed from a material that bows in one direction when heated, so that when the stencil is held against the pad array surface and heated, bowing forces will very tightly press the stencil against the surface, preventing molten solder from migrating between surface and stencil.

REFERENCES:
patent: 5429293 (1995-07-01), Bradley, III et al.
patent: 5685477 (1997-11-01), Mallik et al.
patent: 5764485 (1998-06-01), Lebaschi
J. Slattery et al., "A Primer on the Use of Solder Creams . . . , " Electronic Pkg. and Prod., Oct. 1981, pp. 146-156.
E.J. Harris et al., "LSI Chip Removal and Dressing Tool," IBM Tech. Discl. Bull., vol. 19, No. 5 (Oct. 1976) pp. 1641-1642.

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