Abstract: Alloy compositions and techniques for reducing IMC thickness and oxidation of metals and alloys are disclosed. In one particular exemplary embodiment, the alloy compositions may be realized as a composition of alloy or mixture consisting essentially of from about 90% to about 99.999% by weight indium and from about 0.001% to about 10% by weight germanium and unavoidable impurities. In another particular exemplary embodiment, the alloy compositions may be realized as a composition of alloy consisting essentially of from about 90% to about 99.999% by weight gallium and from about 0.001% to about 10% by weight germanium and unavoidable impurities.

Abstract: Lead-free solder alloys and solder joints thereof with improved drop impact resistance are disclosed. In one particular exemplary embodiment, the lead-free solder alloys preferably comprise 0.0-4.0 wt. % of Ag, 0.01-1.5 wt. % of Cu, at least one of the following additives: Mn in an amount of 0.001-1.0 wt. %, Ce in an amount of 0.001-0.8 wt. %, Y in an amount of 0.001-1.0 wt. %, Ti in an amount of 0.001-0.8 wt. %, and Bi in an amount of 0.01-1.0 wt. %, and the remainder of Sn.

Abstract: A technique for technique for increasing the compliance of lead-free solders containing silver is disclosed. In one particular exemplary embodiment, the technique may be realized as a Sn—Ag—Al alloy composition comprising (0.01-20)% Ag, (0.01-2)% Al, balanced with Sn. In another particular exemplary embodiment, the technique may be realized as a Sn—Ag—Cu—Al alloy composition comprising (0.01-20)% Ag, (0.01-1)% Cu, (0.01-2)% Al, balanced with Sn. In still another particular exemplary embodiment, the technique may be realized as a Sn—Ag—Al—Ni composition comprising (0.01-20)% Ag, (0.01-2)% Al, (0.01-4)% Ni, balanced with Sn. In yet another particular exemplary embodiment, the technique may be realized as a Sn—Ag—Cu—Al—Ni alloy composition comprising (0.01-20)% Ag, (0.01-1)% Cu, (0.01-2)% Al, (0.01-4)% Ni, balanced with Sn.

Abstract: Low melting temperature compliant solders are disclosed. In one particular exemplary embodiment, a low melting temperature compliant solder alloy comprises from about 91.5% to about 97.998% by weight tin, from about 0.001% to about 3.5% by weight silver, from about 0.0% to about 1.0% by weight copper, and from about 2.001% to about 4.0% by weight indium.

Abstract: A technique for increasing the compliance of tin-indium solders is disclosed. In one particular exemplary embodiment, the technique may be realized as a lead free solder alloy comprising from about 58.0% to about 99.998% by weight tin, from about 0.001% to about 40.0% by weight indium, and from about 0.001% to about 2.0% by weight at least one rare earth element.

Abstract: Solder pastes for providing high elasticity, low rigidity solder joints are disclosed. The solder pastes may be used between two parts having large mismatches in their coefficients of thermal expansion and/or when there is a high likelihood of mechanical deformity when the two parts are soldered together. In one particular exemplary embodiment, a solder paste may be realized as a composition comprising a solder powder and high melting temperature particles with a flux, wherein the ratio between solder powder and high melting temperature particles may be between 2:1 and 1:10.

Abstract: A lead-free solder alloy composition comprising tin, silver and copper, and a process for reflow soldering for minimizing tombstoning frequency are disclosed. In one particular exemplary embodiment, the lead-free Sn—Ag—Cu solder alloys for minimizing the tombstoning effect of the present disclosure display high mass fraction during melting and prolonged melting as shown by a widened DSC peaks, that allows for a balanced surface tension on both ends of the chip component to develop. In accordance with further aspects of this exemplary embodiment, the alloys display a mass fraction of solid during melting greater than 20% and a DSC peak width greater than 8° C. using a 5° C./min scan rate. In accordance with further aspects of this exemplary embodiment, the alloy comprises on a weight basis Ag 1-4.5%, Cu 0.3-1% balanced with Sn.

Abstract: Solder pastes for providing high elasticity, low rigidity solder joints are disclosed. The solder pastes may be used between two parts having large mismatches in their coefficients of thermal expansion and/or when there is a high likelihood of mechanical deformity when the two parts are soldered together. In one particular exemplary embodiment, a solder paste may be realized as a composition comprising a solder powder and high melting temperature particles with a flux, wherein the ratio between solder powder and high melting temperature particles may be between 2:1 and 1:10.

Abstract: An integrated underfilling process for attaching a chip/die having conductive solder bump contacts to a substrate. The process involves B-staging filled underfill on the chip/die, depositing a fluxing unfilled underfill onto the surface of the substrate, mating the chip/die with the B-staged underfill to the substrate and reflowing the assembled chip/substrate. The B-staged filled underfill reduces the coefficient of thermal expansion of the underfill fillet and the fluxing unfilled underfill removes metal oxide from the surface of the solder bump contacts and bond pads to promote the formation of reliable metallurgical joints.

Abstract: A new method has been developed to provide underfill to chips mounted on substrates. First, an underfill is dispensed on the substrate. Second, the bumps of the chip are dipped in a flux that does not contain filler. Third, the chip that has been dipped in a tacky thermosettable flux is placed on the substrate, and fourth, the chip is soldered to the substrate, and simultaneously the underfill is cured. This process eliminates the interference on solder joints caused by the presence of filler in filled no-flow underfill. In addition, the fluxing property of the flux allows the use of underfills with emphasis on curing and mechanical properties instead of fluxing performance. Accordingly, a mounted device with reliable solder joints and underfill encapsulation is obtained.

Abstract: An integrated void-free process has been developed for attaching a solder bumped chip to a substrate. The chip is first dipped in a tacky thermosettable flux, and the chip is mounted on the substrate. An underfill is dispensed along the edge of the chip The device is then sent into the reflow furnace to complete the underfilling (which optionally can be completed before reflow), solder reflowing and underfill curing. The flux also acts as a physical barrier minimizing, if not eliminating, the interference of filler on solder wetting and resulting metallurgical joints formed between the solder and the bond pads. The process allows for the integration of a void free conventional capillary flow underfilling process and a pre-deposited fluxing underfilling process by using a tacky thermosettable flux, avoiding the problems associated with each of the individual processes and requiring less time for the overall process.

Abstract: A new method has been developed to provide underfill to chips mounted on substrates. First, an underfill is dispensed on the substrate. Second, the bumps of the chip are dipped in a flux that does not contain filler. Third, the chip that has been dipped in a tacky thermosettable flux is placed on the substrate, and fourth, the chip is soldered to the substrate, and simultaneously the underfill is cured. This process eliminates the interference on solder joints caused by the presence of filler in filled no-flow underfill. In addition, the fluxing property of the flux allows the use of underfills with emphasis on curing and mechanical properties instead of fluxing performance. Accordingly, a mounted device with reliable solder joints and underfill encapsulation is obtained.

Abstract: An integrated void-free process has been developed for attaching a solder bumped chip to a substrate. The chip is first dipped in a tacky thermosettable flux, and the chip is mounted on the substrate. An underfill is dispensed along the edge of the chip The device is then sent into the reflow furnace to complete the underfilling (which optionally can be completed before reflow), solder reflowing and underfill curing. The flux also acts as a physical barrier minimizing, if not eliminating, the interference of filler on solder wetting and resulting metallurgical joints formed between the solder and the bond pads. The process allows for the integration of a void free conventional capillary flow underfilling process and a pre-deposited fluxing underfilling process by using a tacky thermosettable flux, avoiding the problems associated with each of the individual processes and requiring less time for the overall process.