Multilayer Flexcircuit Wart Package
Original Publication Date: 1985-Jan-01
Included in the Prior Art Database: 2005-Feb-18
A multilayer printed circuit board 1 (Figs. 1 and 2) is described, the thin upper layer 2 of which is a flexcircuit with chip sites 3 (warts). A soft material 4, deposited on chip sites 3 below upper layer 2, supports the warts and ensures that layer 2, carrying chips 5, remains soft along chip sites 3, so that differences in thermal expansion between the chip and its carrier are compensated for. The warts also provide a means for pressing chips 5 against the metal surface of a heat sink 6. The height of the warts is such that chips 5 protrude from the other components 7. Where upper layer 2 directly contacts the other layers, plated through holes 8 may be provided for layer-to-layer connection. In the multilayer flexcircuit wart package, the contours of the copper-covered upper layer 2 are formed in a press and then etched.