Recent Advances in High Density Area Array Interconnect Bonding for 3D Integration

The demand for more complex and multifunctional micro systems with enhanced performance characteristics for military applications is driving the electronics industry toward the use of best-of-breed materials and device technologies. Threedimensional (3-D) integration provides a way to build complex microsystems through bonding and interconnection of individually optimized device layers without compromising system performance and fabrication yield. Bonding of device layers can be achieved through polymer bonding or metal-metal interconnect bonding with a number of metalmetal systems. RTI has been investigating and characterizing Cu-Cu and CulSn-Cu processes for high density area array imaging applications, demonstrating high yield bonding between sub-I5 11m pads on large area array configurations. This paper will review recent advances in the development of high yield, large area array metal-metal interconnects which enable 3-D integration of heterogeneous materials (e.g. HgCdTe with silicon) and heterogeneous fabrication processes (e.g. infrared emitters or microbolometers with ICs) for imaging and scene projector applications.