DEAD-BUG TO LIVE-BUG COPLANARITY ALGORITHM
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2001-Dec-31
"Coplanarity" is an important IC-packaging speci- fication. It is typically applicable to SMT (surface mount technology) IC packaging technology, and is defined as the deviation of each lead of the part from the "seating plane" of the part (see Figure 1). "Dead-bug" coplanarity is the term used to describe the coplanarity which results when the leads of the part are not carrying the weight of the part during measurement (such as might arise if the part is upside-down with its leads pointing upwards, or if the part is right-side up but resting on a pedestal with the leads completely suspended in the air). "Live-bug" refers to the coplanarity of the leads when they are car- rying the weight of the part (as in Figure 1). With ever increasing package weight, the dilference between dead- bug and live-bug coplanarity is not negligible, and can therefore influence product yield.