Abstract: Increasing standoff height for surface mount components mounted to a laminate by image screening at least one standoff structure in a footprint area on the laminate surface. The standoff structure may comprise a filled epoxy and curing agents and may be cured by thermal treatment or by exposure to actinic radiation. The use of legend ink as a standoff structure offers a method and a structure for improving component standoff height without additional processing operations or cost.

Abstract: An electronic package having a solder interconnect liquidus temperature hierarchy to limit the extent of the melting of the C4 solder interconnect during subsequent second level join/assembly and rework operations. The solder hierarchy employs the use of off-eutectic solder alloys of Sn/Ag and Sn/Cu with a higher liquidus temperature for the C4 first level solder interconnections, and a lower liquidus temperature alloy for the second level interconnections. When the second level chip carrier to PCB join/assembly operations occur, the chip to chip carrier C4 interconnections do not melt completely. They continue to have a certain fraction of solids, and a lower fraction of liquids, than a fully molten alloy. This provides reduced expansion of the solder join and consequently lower stresses on the C4 interconnect.

Abstract: A lead free solder hierarchy for use in the second level solder connection of electronic components such as joining an electronic module to a circuit board. An off-eutectic solder concentration of SnCu or SnAg is used for the module side connection. This off-eutectic solder contains sufficient intermetallics to provide the module side connection with a robust second level assembly and rework process. The off-eutectic composition provides an inter-metallic phase structure in the module side fillet during assembly. The inter-metallic phase structure eliminates problems of tilt and collapse during second level assembly and aids in rework by providing a more cohesive joint allowing removal of the columns from the board without simultaneous removal from the module.

Abstract: An electronic package having a solder interconnect liquidus temperature hierarchy to limit the extent of the melting of the C4 solder interconnect during subsequent second level join/assembly and rework operations. The solder hierarchy employs the use of off-eutectic solder alloys of Sn/Ag and Sn/Cu with a higher liquidus temperature for the C4 first level solder interconnections, and a lower liquidus temperature alloy for the second level interconnections. When the second level chip carrier to PCB join/assembly operations occur, the chip to chip carrier C4 interconnections do not melt completely. They continue to have a certain fraction of solids, and a lower fraction of liquids, than a fully molten alloy. This provides reduced expansion of the solder join and consequently lower stresses on the C4 interconnect.

Abstract: An electronic package having a solder interconnect liquidus temperature hierarchy to limit the extent of the melting of the C4 solder interconnect during subsequent second level join/assembly and rework operations. The solder hierarchy employs the use of off-eutectic solder alloys of Sn/Ag and Sn/Cu with a higher liquidus temperature for the C4 first level solder interconnections, and a lower liquidus temperature alloy for the second level interconnections. When the second level chip carrier to PCB join/assembly operations occur, the chip to chip carrier C4 interconnections do not melt completely. They continue to have a certain fraction of solids, and a lower fraction of liquids, than a fully molten alloy. This provides reduced expansion of the solder join and consequently lower stresses on the C4 interconnect.

Abstract: A lead free solder hierarchy for use in the second level solder connection of electronic components such as joining an electronic module to a circuit board. An off-eutectic solder concentration of SnCu or SnAg is used for the module side connection. This off-eutectic solder contains sufficient intermetallics to provide the module side connection with a robust second level assembly and rework process. The off-eutectic composition provides an inter-metallic phase structure in the module side fillet during assembly. The inter-metallic phase structure eliminates problems of tilt and collapse during second level assembly and aids in rework by providing a more cohesive joint allowing removal of the columns from the board without simultaneous removal from the module.