Metal fusion bonding – Process – Plural joints
Patent
1990-12-06
1992-10-13
Heinrich, Samuel M.
Metal fusion bonding
Process
Plural joints
228254, H05K 334
Patent
active
051543419
ABSTRACT:
An improved electrical component package comprises a component attached to a substrate by a plurality of multisolder interconnections. Each interconnection comprises a preformed spacer bump composed of a first solder alloy, preferably a lead-base tin alloy containing greater than 90 weight percent lead. The spacer bump is bonded to a metallic electrical contact of the component and rests against a corresponding metallic electrical contact of the substrate, but is not directly metallurgically bonded thereto. Each interconnection further comprises a sheath portion formed of a second compositionally distinct solder alloy having a liquidus temperature less than the first alloy solidus temperature. A preferred second solder is a tin-lead alloy comprising between about 30 and 50 weight percent lead and the balance tin or indium. The sheath is bonded to the spacer bump and to the substrate contact to complete attachment of the component to the substrate and preferably extends to the component contact, encasing the bump, to produce an interconnection having an hour glass configuration to reduce thermal fatigue stresses at the solder bonds to the contacts. A method for forming the multisolder interconnection is presented wherein the sheath is derived from a solder microball situated on the substrate contact in juxtaposition to the spacer bump for reflow.
REFERENCES:
patent: 4545610 (1985-10-01), Lakritz et al.
patent: 4739917 (1988-04-01), Baker
patent: 4818728 (1989-04-01), Rai et al.
patent: 4821946 (1989-04-01), Abe et al.
patent: 4878611 (1989-11-01), LoVasco et al.
patent: 4914814 (1990-04-01), Behun et al.
patent: 4967950 (1990-11-01), Legg et al.
patent: 5007163 (1991-04-01), Pope et al.
IBM Technical Disclosure Bulletin, "Copper Ball Standoff . . . ", vol. 29, No. 4, p. 1646, Sep. 1986.
Research Disclosure, "Solder Column Extension", No. 260, Dec. 1985.
Koopman, N., "Solder Joining Technology", Mat. Res. Soc. Symp. Proc., vol. 154, (1989), pp. 431-440.
Melton Cynthia M.
Raleigh Carl J.
Scheifers Steven
Fekete Douglas D.
Heinrich Samuel M.
Motorola Inc.
LandOfFree
Noncollapsing multisolder interconnection does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Noncollapsing multisolder interconnection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Noncollapsing multisolder interconnection will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1295191