Abstract: A method for mounting a semiconductor package onto PCB is disclosed. A semiconductor package is provided, which comprises a plurality of outer terminals exposed out of an encapsulant. A PCB is provided and has a surface with a plurality of contact pads. Each contact pad has a first exposed side, an opposing exposed second side and a center between the exposed sides. A plurality of first pre-solders and a plurality of second pre-solders are formed on the surface by one single printing. The first pre-solders and the second pre-solders respectively cover the first and second exposed sides of the contact pads, spaces between the opposing first and second pre-solders expose the centers of the contact pads. Then the first and second pre-solders are reflowed and the semiconductor package is mounted on the PCB.

Abstract: A method for mounting a semiconductor package onto PCB is disclosed. A semiconductor package is provided, which comprises a plurality of outer terminals exposed out of an encapsulant. A PCB is provided and has a surface with a plurality of contact pads. Each contact pad has a first exposed side, an opposing exposed second side and a center between the exposed sides. A plurality of first pre-solders and a plurality of second pre-solders are formed on the surface by one single printing. The first pre-solders and the second pre-solders respectively cover the first and second exposed sides of the contact pads, spaces between the opposing first and second pre-solders expose the centers of the contact pads. Then the first and second pre-solders are reflowed and the semiconductor package is mounted on the PCB.

Abstract: A method for mounting a semiconductor package onto PCB includes a semiconductor package comprising a plurality of outer terminals exposed out of an encapsulant. A PCB having a surface with a plurality of contact pads is provided. Each contact pad has a first exposed side, a second exposed side and a center between the exposed sides. A plurality of first pre-solders and second pre-solders are formed on the surface to cover the first and second exposed sides of the contact pads respectively, the centers of the contact pads between the first and second pre-solders being exposed. Then the first and second pre-solders are reflowed and the semiconductor package is mounted on the PCB. When the outer terminals are connected to the contact pads, each first pre-solder and second pre-solder are flowed toward the centers of the contact pad to prevent the fine pitch contact pads from bridging.

Abstract: A cavity-down semiconductor package mainly includes a heat spreader, a substrate, and a chip. The substrate has an outer surface, an inner surface opposing to the outer surface and an opening passing through the outer and inner surfaces. The inner surface is attached to the heat spreader to form a chip carrier with a chip cavity. The chip is located in the opening and electrically connected to the substrate. The substrate includes a metal cover layer over the inner surface. The metal cover layer can be bonded to the heat spreader to establish a thermal-coupling relationship to improve adhesion, heat conductibility and electrical performance between the substrate and the heat spreader.

Abstract: A method for mounting a semiconductor package onto PCB is disclosed. A semiconductor package is provided, which comprises a plurality of outer terminals exposed out of an encapsulant. A PCB is provided and has a surface with a plurality of contact pads. Each contact pad has a first exposed side, an opposing exposed second side and a center between the exposed sides. A plurality of first pre-solders and a plurality of second pre-solders are formed on the surface by one single printing. The first pre-solders and the second pre-solders respectively cover the first and second exposed sides of the contact pads, spaces between the opposing first and second pre-solders expose the centers of the contact pads. Then the first and second pre-solders are reflowed and the semiconductor package is mounted on the PCB.