Direct chip attach

Direct Chip Attach commonly references a technique in which the chip is attached directly to the organic laminate. This paper deals with the general requirements for the printed circuit laminate on which a flip chip with controlled callapse chip connection (C4) is directly attached. One of the key requirements is to reduce the coefficient of thermal expansion of the laminate. This paper also shows the calculated results for laminates made with fibers and resins whose material constants are realizable today, and concludes that it is possible to make low-expansion laminates suitable for direct chip attach.