Hughes Aircraft Company

Brook D Raymond

Tom Y Chi

A gallium arsenide monolithic microwave integrated circuit (MMIC) chip (12) has microelectronic devices (16, 18) formed on a frontside surface (12a), and via holes (12c, 12d) formed through the chip (12) from the frontside surface (12a) to a backside surface (12b). The backside surface (12b) of the chip (12) is bonded to a molybdenum carrier (14) by an eutectic gold/tin alloy (20). A barrier layer (22) including a refractory metal nitride material (22a) is sputtered onto the backside surface (12b) and into the via holes (12c, 12d) of the chip (12) prior to bonding. The barrier layer (22) blocks migration of tin from the eutectic gold-tin alloy (20) through the via holes (12c,-12d) to the frontside surface (12a) of the chip (12) during the bonding operation, thereby preventing migrated tin from adversely affecting the microelectronic devices (16, 18).

Bonding of integrated circuit chip to carrier using gold/tin eutectic

A gallium arsenide monolithic microwave integrated circuit (MMIC) chip (12) has microelectronic devices (16,18) formed on a frontside surface (12a), and via holes (12c,12d) formed through the chip (12) from the frontside surface (12a) to the backside surface (12b). The backside surface (12b) of the chip (12) is bonded to a molybdenum carrier (14) by an eutectic gold/tin alloy (20). A barrier layer (22) including a refractory metal nitride material (22a) is sputtered onto the backside surface (12b) and into the via holes (12c,12d) of the chip (12) prior to bonding. The barrier layer (22) blocks migration of tin from the eutectic gold/tin alloy (20) through the via holes 12c,-12d) to the frontside surface (12a) of the chip (12) during the bonding operation, thereby preventing migrated tin from adversely affecting the microelectronic devices (16,18 ).

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Hermosa Beach, CA, United States of America

Brook D Raymond