International Business Machines Corporation

Pierre M Langevin

Son K Tran

Michael B Vincent

Eric A Johnson

Irving Memis

William E Bernier

Charles F Carey

Robert F White

Eberhard B Gramatzki

Thomas R Homa

Clément J Fortin

Claude Blais

Alain Warren

Julie Nadeau Filteau

Robert L Toutant

Cl&eacute;ment J Fortin

An electronic fabrication process and structure is provided for attaching discrete passive surface mount devices (SMD) to a substrate in a single step. A liquid noflow resin encapsulant containing flux material is dispensed between presoldered pads on a substrate. The SMD, having a pair of electrical contacts, is pressed into said encapsulant so that the electrical contacts make contact with said presoldered pads. Heat is applied to first activate said flux material and then reflow the solder on said presoldered pads to bond said SMD contacts to said presoldered pads. The reflow temperature is maintained for about 180 seconds during which time the resin solidifies. The resin encapsulant fills the space between substrate and SMD and forms fillets around the solder bonded contacts.

SMT passive device noflow underfill methodology and structure

A method and structure for coupling a semiconductor substrate (e.g., a semiconductor chip) to an organic substrate (e.g., a chip carrier). The coupling interfaces a solder member (e.g., a solder ball) to both a conductive pad on the semiconductor substrate and a conductive pad on the organic substrate. Thermal strains on the solder member during thermal cycling may be reduced by having a surface area of the pad on the semiconductor substrate exceed a surface area of the pad on the organic substrate. Thermal strains on the solder member during thermal cycling may also be reduced by having a distance from a centerline of the solder member to a closest lateral edge of the semiconductor substrate exceed about 0.25 mm.

Extension of fatigue life for C4 solder ball to chip connection

Ink jet printing apparatus is employed to form a non-polar ink stop line around a chip site on the polar surface of an organic laminate substrate. The non-polar ink stop line acts to confine polar liquid flux from spreading after application of the flux to the chip site prior to chip joining. Excessive flux spreading results in insufficient flux being present at the chip site for the formation of good electrical connections during solder reflow upon chip joining.

Control of flux by ink stop line in chip joining

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Granby, Canada

Pierre M Langevin