Abstract: A solder paste comprises an amount of a first solder alloy powder between about 60 wt % to about 92 wt %; an amount of a second solder alloy powder greater than 0 wt % and less than about 12 wt %; and a flux; wherein the first solder alloy powder comprises a first solder alloy that has a solidus temperature above about 260° C.; and wherein the second solder alloy powder comprises a second solder alloy that has a solidus temperature that is less than about 250° C.

Abstract: A method is provided for the forming of a metallic solder joint without a liquid flux to create a solder joint that has minimal voids and can be reflowed multiple times without void propagation. This process can be done for any solder alloy, and is most specifically used in the application of first level thermal interface in a IC or micro processor or BGA microprocessor.

Abstract: Methods and apparatus are provided for attaching a heat spreader to a die and includes disposing a solder thermal interface material between a first surface of a die and a first surface of a heat spreader without disposing a liquid flux between the die and the heat spreader to form an assembly, wherein at least one of the first surface of the die and a first surface of the heat spreader have disposed thereon a metallization structure comprising a transition layer and a sacrificial metallization layer, the sacrificial metallization layer disposed as an outer layer to the metallization structure adjacent the solder thermal interface material; and heating the assembly to melt the thermal interface and attach the die to the heat spreader.

Abstract: Various embodiments of the invention provide laminate composite preform foils for high-temperature Pb-free soldering applications. The laminate composite preform foil is composed of a high-melting, ductile metal or alloy core layer and a low-melting solder coating layer at either side of the core layer. During soldering, the core metal, liquid solder layer, and substrate metals react and consume the low-melting solder phase to form high-melting intermetallic compound phases (IMCs). The resultant solder joint is composed of a ductile core layer sandwiched by the IMCs layers at substrate sides. The joint has a much higher remelt temperature than the original melting temperature of the initial solder alloy coating, allowing subsequent mounting of packaged devices.

Abstract: A solder preform has gaps extending from the boundary of preform towards the preform center. During reflow soldering, the gaps close from the center towards the boundary. This allows flux and gasses to escape the interface between the solder and the substrate. Particularly, flux accumulates in the spaces formed by the gaps and is forced to the edge of the solder preform as the gap closes. In further embodiments, channels are formed on one or both surfaces of the solder preform. In addition to further assisting in the escape of gas and flux during reflow, the channels and gaps increase the effectiveness of oxygen purging using inert or reducing gasses in the reflow chamber. Additionally, the channels and gaps increase the effectiveness of vacuum solder.

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: 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: A method for joining component bodies of material over bonding regions of large dimensions by disposing a plurality of substantially contiguous sheets of reactive composite materials between the bodies and adjacent sheets of fusible material. The contiguous sheets of the reactive composite material are operatively connected by an ignitable bridging material so that an igniting reaction in one sheet will cause an igniting reaction in the other. An application of uniform pressure and an ignition of one or more of the contiguous sheets of reactive composite material causes an exothermic thermal reaction to propagate through the bonding region, fusing any adjacent sheets of fusible material and forming a bond between the component bodies.

Abstract: A technique for forming a thermally conductive interface with patterned metal foil is disclosed. In one particular exemplary embodiment, the technique may be realized as a thermally conductive metal foil having at least one patterned surface for facilitating heat dissipation from at least one integrated circuit device to at least one heat sink. The metal foil preferably has a characteristic formability and softness that may be exemplified by alloys of lead, indium, tin, and other malleable metals, and/or composites comprising layers of at least one malleable metal alloy.

Abstract: Materials having increased mobility after heating are disclosed. In one particular exemplary embodiment, the materials may be realized as a material which has reduced apparent molecular weight and/or viscosity and thus increased mobility after a heating process, and which consequently allows material residue to be more easily removed during subsequent cleaning processes. Such a material may be useful in any industrial process which requires heating the material followed by removing material residue.

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: A technique for forming a thermally conductive interface with patterned metal foil is disclosed. In one particular exemplary embodiment, the technique may be realized as a thermally conductive metal foil having at least one patterned surface for facilitating heat dissipation from at least one integrated circuit device to at least one heat sink. The metal foil preferably has a characteristic formability and softness that may be exemplified by alloys of lead, indium, tin, and other malleable metals, and/or composites comprising layers of at least one malleable metal alloy.

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: The object of this invention is to employ a solder alloy comprising tin/lead/silver in order to provide a wider solidification range and achieve balance between the surface tensions of both side of a small leadless component. The expanded solidification range slows the melting and wetting time so as to balance the surface tension of the molten solder, and in turn reduces the tombstoning frequency. The preferred Ag concentration is 0.2-0.5% in weight, the more preferred Ag concentration is 0.3-0.4% in weight. For reflow soldering of small leadless components, the pastes made with the alloy compositions of Sn62.6Pb37Ag0.4 and Sn63Pb36.6Ag0.4 results in improvements in tombstoning.

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.