Beginning-to-End Wafer Bonding for Advanced Optical Systems

摘要

The old adage "Work Smarter, Not Harder" is certainly applicable in today's competitive marketplace for Optical MEMS. In order to survive the current economic conditions, high volume manufacturers must get optimum performance and yield from each design and manufactured component. Wafer bonding, and its numerous variants, is entering mainstream production environments by providing solutions throughout the production flow. For example, SOI (silicon on insulator) and other laminated materials such as GaAs/Si are used as cost effective alternatives to molecular epitaxy methods for Bragg mirrors, rf resonators, and hybrid device fabrication. Temporary wafer bonding is used extensively to allow fragile compound semiconductors to be attached to rigid support wafers. This allows for front side and backside processing with a reduction in wafer breakage and increases in thickness uniformity results after backgrind operations. Permanent wafer bonding is used to attach compound semiconductors to each other or silicon to completely integrate optical components and logic or MEMS components. Permanent hermetic sealing is used for waveguide formation and, when combined with vacuum sealing, higher performance is achieved for RF resonators. Finally, many of the low temperature solders and eutectic alloys are finding application in low temperature wafer-to-wafer level packaging of optical devices to ceramic packages. Through clever application of these bonding methods, throughput increases and reduction in fabrication complexity gives a clear edge in the market place. This presentation will provide guidelines and process overviews needed to adopt wafer-to-wafer bonding technologies into the high volume-manufacturing environment.