A simple probe card for testing bumped fine pitch devices

摘要

Today's ever increasing miniaturization drives down the bump pitch on the components and at the same time clock frequency increases. This in turn puts high demands on the probe cards used for testing the components. Conventional probe cards with needles can not be used for finer pitches than approximately 0.5mm. Furthermore they have problems with high frequencies due to their long, tightly spaced needles. From this background it is necessary to develop other types of probe cards for testing of fine pitch components. Several solutions with varying performance have been presented but they all have a common drawback, high cost. In this paper a new type of probe card for testing of bumped fine pitch devices with potential to be manufactured at low cost is presented and evaluated. This probe card is manufactured from a flexible printed circuit board laminate in which resilient tabs with conductors are formed. These tabs forms individual contact springs for each bump and are furthermore situated in holes to give a self-aligning effect against the bumps. One of the main features with this method is that almost everything is integrated in the flexible laminate. The only extra parts needed are a simple base plate with a square hole slightly larger then the chip and something to hold down the chip. Presented here are measurements on a probe card for a test chip with 88 peripheral bumps on a 200-mum pitch.