Pad Deletion Test Technique
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-02
Testing of isolated pads, which have been either completely or incompletely isolated by laser severing of the pad neck, may be accomplished by momentarily heating the pad with a laser and measuring the thermal result on the other side of the neck. Incompletely severed necks retain thermally conductive electrical connection material, which material provides faster heat transfer than the characteristic heat transfer of a completely severed neck. A ceramic substrate may contain on its top (chip-side) surface a number of engineering change (EC) pads that can be used to repair or modify the circuits interconnecting individual chips and off-module connectors; Fig. 1 illustrates one of these EC pads which has been modified for one kind of rework operation (a so-called "delete").