Abstract: Pad array carriers allow greater I/O densities over conventional leaded packages by using an array arrangement for external electrical connections. A pad array carrier (48) is manufactured using a substrate (40) having metal on only one side and unplated through-holes (44). A semiconductor die (50) is mounted on and affixed to the top surface of the substrate with an electrically insulative adhesive (51). The use of the insulative adhesive allows routing of signal traces into the die mounting region directly underneath the die. Wire bonds (52) connect the die to metal traces (46) on the substrate. A package body (54) is formed on the substrate covering the die and wire bonds (52). Solder balls (56 & 58) are directly attached to the backside of the solder pads (47) by way of the through-holes.

Abstract: A lead-on-chip (LOC) device (44) has a comb-shaped (32) or a cut-out (38) tape as the means of attachment for the leads (14) to the die surface. The LOC tape has cut-outs between the leads to minimize the amount of tape between the leads. The cut-outs are provided by either making the tape comb-shaped so that it has teeth and gaps between each tooth or by having oblong-shaped cut-outs in the tape corresponding in location the gaps between the leads. By minimizing the tape to die interface between the leads, the chance of voids forming between the leads is eliminated.

Abstract: A particular layout (38) of transistors along a continuous conductor line (54), such as the transistors in a CMOS inverter, has been found which reduces breaks or voids in the conductor line due to electromigration of the conductor atoms from predominantly unidirectional current flows. The conductor line may be a metal line. By alternating the two types of transistors, p- and n-type (40, 41, 46 & 47), along the length of the metal line, almost the entire length of the line can be changed to one with bidirectional current flow which significantly reduces the mean-time-to-failure for electromigration-related damage. The layout arrangement will find greater advantage for large transistors, long metal lines, relatively large unidirectional current flows and devices that run at high frequency, such as clock drivers.