Reworkable Chip-On-Board Package
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
This article describes a technique which will allow one rework cycle per chip site when a chip-on-board package is utilized. Back bonded chip-on-board packages are difficult to replace when defective chips must be replaced and the rework may cause damage to the surrounding area. In order to improve board yields, a technique which allows one rework cycle per chip site is shown. Fig. 1 shows the cross-section of a two-layer board 10 on substrate 11, comprised of a central ground plane 12 and a top layer 13 with board pads 14 thereon. Chip pockets 15 are milled through the top layer 13 of the board 10 to expose ground plane 12. Before a chip 16 is back bonded, in chip pocket 15, to ground plane 12 with an epoxy 17, the exposed ground plane 12 may be plated with nickel and gold (not shown).