Abstract: A substrate including a die side interconnect pattern having a first solder mask thickness, and a board side interconnect pattern having a second solder mask thickness, where the second thickness is greater than the first thickness. Fabrication process using dry film solder mask can apply a first laminate thickness forming a die side solder mask, and a second laminate thickness forming a board side solder mask; the second thickness being greater than the first thickness. Fabrication process using a liquid solder resist can apply a first number of passes of solder resist forming a die side solder mask, and a second number of passes of solder resist forming a board side solder mask, where the board side thickness is greater than the die side thickness.

Abstract: An area array package comprising a die attach area for attaching a die to a substrate, a network of staggered bond fingers, and a network of bond islands for coupling bond wires between the bond islands and die bond pads is provided. A network of package leads, for example, a network of solder balls in a ball grid array, is depopulated to permit greater trace route flexibility and via placement within the substrate. Stacked die and multi-chip packages are also disclosed. A method for accommodating a high pin-count die in an area array package is also included.

Abstract: An area array package comprising a die attach area for attaching a die to a substrate, a network of staggered bond fingers, and a network of bond islands for coupling bond wires between the bond islands and die bond pads is provided. A network of package leads, for example, a network of solder balls in a ball grid array, is depopulated to permit greater trace route flexibility and via placement within the substrate. Stacked die and multi-chip packages are also disclosed. A method for accommodating a high pin-count die in an area array package is also included.

Abstract: An integrated circuit package is constructed by attaching lower dies to a substrate that has bond fingers deposited on its surface. One lower die and its associated bond fingers are located offset from the center of the substrate. The lower dies are electrically coupled to the substrate's bond fingers with lower bond wires. An upper die is stacked on at least one of the lower dies. The upper die is electrically coupled, with bond wires, to the lower die upon which it is mechanically coupled. Each of the lower dies may be coupled to the other lower die with bond wire bridges that span the lower bond wires. The upper die may be electrically coupled, with bond wire bridges, to any or all of the lower dies.

Abstract: An area area package includes a plurality of solder balls not used as electrical connectors. These non-connected solder balls, or “dummy balls,” provide protection to solder balls connected to live pins and therefore increase reliability of the area array package. The dummy balls may be placed in the corners, along the diagonals or in other high stress location on the area array package. To further increase reliability, a continuous copper ball land pad may be used to connect each group of corner dummy balls. Continuous copper pads help to reduce stress on the dummy balls. For center-depopulated BGA packages, an array of dummy balls may be used in the center of the package to prevent substrate bending and improve drop test reliability.