Development of super fine pattern PWB MOSAIC

A variety of build up and/or multi layer PWBs is proposed. In each case, the key points are fine patterning, small via hole connection and surface mount compatibility. Previously, we developed a 2 layer flexible circuit, without an adhesive layer, called Hyper Flex/sup TM/, which is capable of lower thickness and narrower lines compared with conventional flexible circuits with adhesion. Using this high density print wiring board, we have developed a unique and simple build up PWB, MOSAIC (Multiple Organic Accumulated Inter Connection) series. MOSAIC contains 2 series, MOSAIC-F and MOSAIC-R. MOSAIC-F consists of all flexible layers with ultra fine patterns for CSP/MCM semiconductor attachment. MOSAIC-R consists of a core layer and flex layers (Hyper Flex/sup TM/) for fine pattern multi layer mother boards. This paper introduces MOSIAC-R, which achieves ultra fine pattern multi layer PWBs at large area with reasonable cost for digital mobile products.