Metallized Ceramic and Multi-Level Hybrid Fan-Out Technique
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Fan-out from a substrate-mounted LSI chip is achieved using only two simple buried fan-out layers and a relatively simple top surface fan-out pattern. Only a few layers of a multilayer ceramic (MLC) substrate are used to accomplish a limited amount of chip fan-out so that the remaining chip fan-out lines occupy only two wiring spaces between adjacent chip connections on the top surface of the ceramic substrate. Fig. 1 shows a layout of one quadrant of a typical chip footprint. The twelve lines shown that use buried layers (two layers are required) make it possible to fan-out the remaining lines with a maximum of two lines between chip connection pad locations. It is important to note that two lines never have to pass between two vias that are in adjacent positions since power vias occupy every other position in the substrate.