A composition for use in an electronic assembly process, the composition comprising a filler dispersed in an organic medium, wherein: the organic medium comprises a polymer; the filler comprises one or more of graphene, functionalized graphene, graphene oxide, a polyhedral oligomeric silsesquioxane, graphite, a 2D material, aluminum oxide, zinc oxide, aluminum nitride, boron nitride, silver, nano fibers, carbon fibers, diamond, carbon nanotubes, silicon dioxide and metal-coated particles, and the composition comprises from 0.001 to 40 wt. % of the filler based on the total weight of the composition.

A composition for use in an electronic assembly process, the composition comprising a filler dispersed in an organic medium, wherein: the organic medium comprises a polymer; the filler comprises one or more of graphene, functionalized graphene, graphene oxide, a polyhedral oligomeric silsesquioxane, graphite, a 2D material, aluminum oxide, zinc oxide, aluminum nitride, boron nitride, silver, nano fibers, carbon fibers, diamond, carbon nanotubes, silicon dioxide and metal-coated particles, and the composition comprises from 0.001 to 40 wt. % of the filler based on the total weight of the composition.

A technique for fabricating bumps on a substrate is disclosed. A substrate that includes a set of pads formed on a surface thereof is prepared. A bump base is formed on each pad of the substrate. Each bump base has a tip extending outwardly from the corresponding pad. A resist layer is patterned on the substrate to have a set of holes through the resist layer. Each hole is aligned with the corresponding pad and having space configured to surround the tip of the bump base formed on the corresponding pad. The set of the holes in the resist layer is filled with conductive material to form a set of bumps on the substrate. The resist layer is stripped from the substrate with leaving the set of the bumps.

A technique for fabricating bumps on a substrate is disclosed. A substrate that includes a set of pads formed on a surface thereof is prepared. A bump base is formed on each pad of the substrate. Each bump base has a tip extending outwardly from the corresponding pad. A resist layer is patterned on the substrate to have a set of holes through the resist layer. Each hole is aligned with the corresponding pad and having space configured to surround the tip of the bump base formed on the corresponding pad. The set of the holes in the resist layer is filled with conductive material to form a set of bumps on the substrate. The resist layer is stripped from the substrate with leaving the set of the bumps.

A microelectronic device has a bump bond structure including an electrically conductive pillar with an expanded head, and solder on the expanded head. The electrically conductive pillar includes a column extending from an I/O pad to the expanded head. The expanded head extends laterally past the column on at least one side of the electrically conductive pillar. In one aspect, the expanded head may have a rounded side profile with a radius approximately equal to a thickness of the expanded head, and a flat top surface. In another aspect, the expanded head may extend past the column by different lateral distances in different lateral directions. In a further aspect, the expanded head may have two connection areas for making electrical connections to two separate nodes. Methods for forming the microelectronic device are disclosed.

A microelectronic device has a bump bond structure including an electrically conductive pillar with an expanded head, and solder on the expanded head. The electrically conductive pillar includes a column extending from an I/O pad to the expanded head. The expanded head extends laterally past the column on at least one side of the electrically conductive pillar. In one aspect, the expanded head may have a rounded side profile with a radius approximately equal to a thickness of the expanded head, and a flat top surface. In another aspect, the expanded head may extend past the column by different lateral distances in different lateral directions. In a further aspect, the expanded head may have two connection areas for making electrical connections to two separate nodes. Methods for forming the microelectronic device are disclosed.

A flux includes a rosin resin, an activator, a thixotropic agent, and a solvent. The solvent includes 30% by mass or more and 60% by mass or less monovalent alcohol with respect to a total mass amount of the flux. The monovalent alcohol has 18 or more and 24 or less of carbon atoms in one molecule.

A semiconductor package comprises: a printed circuit board including a connection portion; an IC chip arranged on the printed circuit board; a solder portion arranged on the lower surface of the IC chip and coupled to the connection portion; a. bonding layer arranged between the solder portion and the connection portion; and an underfill arranged between the IC chip and the printed circuit board, wherein the bonding layer includes thermosetting resin, and the underfill include thermoplastic resin.

Foundation layers and methods of forming a foundation layer are described. Die pads are formed over a die. A dielectric layer is formed over die pads and the die. The dielectric layer is then recessed to expose top portions of the die pads. A first plurality of sintered conductive vias are formed over the die pads. The first sintered conductive vias are coupled to at least one of the die pads. In addition, a photoresist layer may be formed over the dielectric layer and the top portions of the die pads. Via openings are formed in the photoresist layer. A second plurality of sintered conductive vias may then be formed over the first sintered conductive vias to form a plurality of sintered conductive lines. Each of the first and second sintered conductive vias are formed with a liquid phase sintering (LPS) solder paste.

A substrate (3) and two or more different chips (1a, 1b) having different heating properties (e.g. caused by different dimensions (surface area and/or thickness), heat capacity (C1, C2), absorptivity, conductivity, number and/or size of solder bonds) are provided. A solder material (2) is disposed between the chips (1a, 1b) and the substrate (3). A flash lamp (5) generates a light pulse (6) for heating the chips (1a, 1b), wherein the solder material (2) is at least partially melted by contact with the heated chips (1a, 1b). A masking device (7) is disposed between the flash lamp (5) and the chips (1a, 1b) causing different light intensities (1a, 1b) in different areas (6a, 6b) of the light pulse (6) passing the masking device (7), thereby heating the chips (1a, 1b) with different light intensities (1a, 1b). This may compensate the different heating properties to reduce a spread in temperature between the chips (1a, 1b) as a result of the heating by the light pulse (6). The chips (1a, 1b) may be releasably carried by a chip carrier disposed between the flash lamp (5) and the substrate (3) before being positioned on the substrate (3), wherein the light (6a, 6b) of the light pulse (6) transmitted by the masking device (7) is projected onto the chips (1a, 1b) held by the chip carrier for heating the chips (1a, 1b), releasing them from the chip carrier and transferring them to the substrate (3), wherein the heated chips (1a, 1b) cause melting of the solder material (2) between the chips (1a, 1b) and the substrate (3) for attaching the chips (1a, 1b) to the substrate (3).