Dual chip memory package

Today's computer systems require more main memories than before due to the development of heavy-load softwares and the integration of multiple functions in a computer. However, since the computers became portable the sizes of computers are getting smaller. This means that it is necessary to put more memory chips into a limited space of the computers. In order to fulfil above requirement, a new high density package was developed, which looked the same as conventional plastic packages outside, and contained two chips inside, and named the Dual Chip Package (DCP). In packaging two chips in a package outline, chip-on-tape (COT) technology was combined with lead frames. The tape had wiring patterns inside and interconnection tabs along the periphery of the tape. The lead frames for the DCP were prepared by bonding the inner leads of the lead frames to the interconnection tabs of the tapes. Two chips are attached to the top side and the bottom side of the tape, and wire-bonded onto the tape surface. In the chip attachment and wire bonding process, one side of the tape was coated with an epoxy encapsulant to protect the chips during the wire bonding of the other side. After this process, the assembly processes were the same as those of conventional plastic packages. With DCP, it is possible to change the pin configurations of the package by varying the design of the tape. Reliability tests showed that the DCP met JEDEC level 3 requirement in pre-conditioning tests.