Method of and apparatus for mechanically and electrically testing the quality of joints bonding a chip device to the surface of the substrate of a microminiature module

Abstract

Abstract THE JOINTS BORDING A CHIP DEVICE TO THE SURFACE OF THE SUBSTRATE OF A MICROMINIATURE MODULE ARE TESTED USING MEANS FOR SUPPORTING THE MODULE, A HIGH VELOCITY NOZZLE FROM WHICH A HIGH PRESSURE, HIGH VELOCITY AIR BLAST IS DIRECTED TOWARDS THE FIXEDLY HELD MODULE AND MOINTORING MEANS FOR DETECTING CHANGES IN ELECTRICAL RESISTANCE ACROSS THE JOINT. IT HAS BEEN OBSERVED THAT WHEN THE CHIP-SUBSTRATE JOINT OF THE MICROMINIATURE MODULE IS SUBJECTED TO A HIGH VELOCITY, LOW PRESSURE AIR BLAST, CHIPS VERY WEAKLY BOUND, EITHER AT THE CHIP TO CHIP CONTACT CONNECTION, OR THE CHIP CONTACT TO SUBSTRATE CIRCUIT PATTERN CONNECTION, WILL BE BLOWN OFF THE SUBSTRATE BY THE FORCE OF THE AIR BLAST. FURTHER, POOR OR INTERMITTENT BONDED JOINTS OR CONNECTIONS WHEN SUBJECTED TO AN AIR BLAST WILL UNDERGO CHANGES IN RESISTANCE WHICH CAN BE DETECTED IN AN APPROPRIATE CIRCUIT. GREAT ACCURACY IS ACHIEVED IN DETECTING THESE CHANGES BY PULSING THE AIR BLAST AND ELECTRICALLY COUPLING THE JOINT TO A TRIGGER CIRCUIT, PROVIDED TRIGGER CIRCUIT RESPONSE IS MUCH SHORTER THAN PULSE DURATION.

Inventors

• 👤 Ronald W Bowers

Bibliographic Details