COB - chip on board: enabling fast product upgrades - C-MAC Microtechnology - #2

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Product Variants Our technique provides the ability to enable variants of the main system without significant cost or time penalty. Thermal Management Efficient heat dissipation is a further advantage of COB. C-MAC can supply modules with elaborate thermal management and heat sinking to conduct heat directly from the bare die(s) to the exterior of the package. WHAT IS CHIP ON BOARD? Chip on board is a high-density MCM (Multi-Chip Module) technology that integrates bare semiconductor chips directly on to the interconnect substrate. It is a manufacturing solution that allows fast modification of existing product designs, even where space is at a premium. In COB manufacturing, an unpackaged silicon die is attached directly onto the surface of an FR4, flexible PCB or ceramic substrate and wire bonded to form the electrical connections. An epoxy resin or a silicone coating is then applied on top of the die to encapsulate and protect.Epoxy encapsulants can take the form of a single shot dispense (glob top) or by using a dam and fill technique incorporating different viscosity materials. Silicone encapsulant is usually flooded over a wider area of board and constrained by the outer package or by a ring frame for more localised protection. Silicone is often used where the product will experience wide temperature variations since it’s greater compliance provides a flexible environmental barrier.
For further information contact us at: C-MAC MicroTechnology South Denes, Great Yarmouth, Tel: +44 (0) 1493 743 100Norfolk, NR30 3PX, UK Email: info@cmac.comJanuary 2008