According to the package board of the present invention, each soldering pad formed on the top surface of the package board, on which an IC chip is to be mounted, is small (133 to 170 .mu.m in diameter), so the metallic portion occupied by the soldering pads on the surface of the package board is also small. On the other hand, each soldering pad formed on the bottom surface of the package board, on which a mother board, etc. are to be mounted, is large (600 .mu.m in diameter), so the metallic portion occupied by the soldering pads on the surface of the package board is also large. Consequently, a dummy pattern 58M is formed between conductor circuits 58U and 58U for forming signal lines on the IC chip side surface of the package board thereby to increase the metallic portion on the surface and adjust the rate of the metallic portion between the IC chip side and the mother board side of the package board, protecting the package board from warping in the manufacturing processes, as well as during operation.

A method of electrically modeling a semiconductor package is provided. The method reduces computation time for mutual inductance calculations between interconnect lines of the semiconductor package. Only interconnect within a predetermined distance of an interconnect line being modeled is calculated for mutual inductance. The predetermined distance is selected such that any interconnect line greater than the predetermined distance away from the interconnect line being modeled produces a negligible or small mutual inductance. This greatly reduces the number of calculations for semiconductor packages having a large number of interconnect lines. Each interconnect line modeled is broken into segments for calculating mutual inductance. An algorithm is used that calculates the mutual inductance between a pair of arbitrarily oriented straight line metal segments. The algorithm requires a single integration which significantly reduces computation time when compared with systems solving Maxwell's equation in three dimensions.

Integrated circuit package comprising a power supply distribution wiring and a chip interconnection signal wiring both formed on the top surface of a passive semiconductor interconnection carrier (2) in which a power supply decoupling capacitor is implemented. Spaced wells (4) of a first conductivity type are provided in the surface of said carrier of a second conductivity type. The power supply distribution wiring comprises first and second conductive lines (5,6) within a first wiring level (WL1). Said first conductive lines (5) are deposited on the surface areas of said wells (4) in an ohmic contact relationship and said second conductive lines (6) are deposited on the surface areas of said carrier (2) between said wells (4) in an ohmic contact relationship. Said first and second conductive lines are connected to first second terminals of the power supply, respectively, so that the junction capacitance between said wells (4) and the carrier material (2) embedding said wells forms said decoupling capacitor. At least one active integrated circuit chip (1) is mounted and electrically connected to the passive semiconductor interconnection carrier (2).

A method for forming an electrically conductive line between two layers of insulating material and method for connecting the line through both layers of the insulating material to the opposite surfaces is provided. In the method, first, second and third layers of insulating material are provided wherein the first and third layers are separated by the second layer of insulating material which is different in etch rate from the first and third layers. The edge portion of all three layers is exposed and the insulating layer of the second material is selectively etched to remove the revealed edge portion and provide a slot between the first and third layers of insulating material. Also openings are provided in both the first and third layers of insulating material which communicate with the slot and extend respectively through the layers of the first and third insulating material. Thereafter, a conductive material such as tungsten is deposited in the slot and the openings and also on the face of the stacked insulating material. Finally, the excess tungsten is removed from the faces of the insulating material of the first and third layers leaving a conductive line sandwiched between the first and third insulating layers of the material; also metal remains in the openings formed to thereby form conductive studs extending from the line to the opposite surfaces of the insulating material sandwich so formed.

A circuit arrangement for a flip chip utilizes fixed potential shield traces between various signal traces in a redistribution layer to decrease coupling impedances and crosstalk within the layer. In particular, by orienting a fixed potential shield trace between a pair of signal traces and/or between a pair of differential trace pairs, capacitive coupling between the traces is greatly reduced, thereby permitting the signal traces to be routed closer to one another than would be possible if the shield trace was omitted. Often, minimum line width and spacing design rules may be met to ensure maximum circuit density for the redistribution layer and the associated device interconnections, and without concern for excessive adverse effects due to capacitive coupling between traces in the redistribution layer.