High-performance FCBGA based on multi-layer thin-substrate packaging technology : Packaging technology

We have developed a new concept FCBGA (Flip-Chip Ball Grid Array) based on MLTS (Multi-Layer Thin-Substrate) packaging technology in order to meet the strong demand for high-density, high-performance, and low-cost LSI packages. The most important feature of MLTS packaging is that, only a high-density and high-performance multi-layer thin-substrate remains by removing the metal plate after mounting an LSI chip. The MLTS packaging offers the advantages of 1) good registration accuracy, which makes higher-density and finer-pitch patterning possible, 2) an ideal multi-layer structure that is highly suitable for high-speed and high-frequency applications, 3) excellent flip-chip mounting reliability, which makes higher-pin-count and finer-pitch area array flip-chip interconnection possible, 4) excellent reliability, supported by use of high Tg (Glass Transition Temperature) resin, and 5) cost-effective design achieved as a result of fewer layers fabricated with fine-pitch patterning. We successfully produced a high-performance FCBGA prototype based on our MLTS packaging technology. The prototype comprises an LSI chip connected to approximately 2,500 bonding pads arranged in a 240μm pitch area array, and 1,296 I/O pads for BGA. The prototype FCBGA's excellent long-term reliability was demonstrated through a series of tests conducted on it.