Dual chip memory package

摘要

Today's computer systems require more main memories than beforedue to the development of heavy-load softwares and the integration ofmultiple functions in a computer. However, since the computers becameportable the sizes of computers are getting smaller. This means that itis necessary to put more memory chips into a limited space of thecomputers. In order to fulfil above requirement, a new high densitypackage was developed, which looked the same as conventional plasticpackages outside, and contained two chips inside, and named the DualChip Package (DCP). In packaging two chips in a package outline,chip-on-tape (COT) technology was combined with lead frames. The tapehad wiring patterns inside and interconnection tabs along the peripheryof the tape. The lead frames for the DCP were prepared by bonding theinner 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 wirebonding process, one side of the tape was coated with an epoxyencapsulant to protect the chips during the wire bonding of the otherside. After this process, the assembly processes were the same as thoseof conventional plastic packages. With DCP, it is possible to change thepin configurations of the package by varying the design of the tape.Reliability tests showed that the DCP met JEDEC level 3 requirement inpre-conditioning tests