| In this dissertation,the research focused on the Uncooled infrared focal plane array fabrication technology research which based on the adhesive wafer bonding,and the application of fabrication a uncooled infrared focal plane 640×480 arrays based on silicon germanium/silicon multi-quantum well materials.However,it was also provided experience and ideas for other novel sensitive film material applied in MEMS sensor fabrication.Firstly,it researched the SiGe/Si multi-quantum well material properties and the traditional micro-bridge structure of the micro-bolometer array pixel.Based on these,it proposed a micro-bolometer array pixel of micro-bridge structure-fabrication design process which accommodate to the SiGe/Si multi-quantum well material.Then,the 40×40-L-shaped cantilever micro-bridge cell,the 35×40-U-shaped cantilever micro-bridge cell and the 35×35-I-shaped cantilever micro-bridge cell have been designed by the structure-fabrication design process.The difficult points in fabrication process also have been analyzed.Secondly,based on the existed adhesive bonding research,the theory of the PDAP adhesive bonding defects formation have been proposed.Then,it founded a method to the PDAP adhesive bonding key parameters optimization and obtained a micron size void-free bonding results.The theory and method were also a valuable reference for the thermoplastic polymer adhesive bonding.Thirdly,it research on the stress effect of micro-bridge array fabrication processes,including Low-stress wafer thinning,Silicon Nitride-Titanium-Silicon Nitride cantilever stress control,high-precision lithography on polymer substrate.Based on experimental research,a self-stop low-stress wafer speed thinning process have been founded.By these,the micron size sensitive film transfer technology have been founded,and used in micro-bolometer array fabrication.For the cantilever stress mismatch problem in micro-bolometer fabrication,Silicon Nitride-Titanium-Silicon Nitride cantilever stress control method which by changing the PECVD silicon nitride deposition parameters have been founded through the experimental research and theoretical analysis.By experimental research,the optimization lithographic alignment marks have been designed,the highest alignment accuracy to within ±0.2 microns.Fourthly,it research on the micro-bridge array generally fabrication processes,including micron size electrode interconnect,thin metal film low temperature deposition and patterning process,non-metallic film etching process.Through the independent electroplating,the optimization gold interconnect electrode process parameters have been determined.And the test problem,plating rate problem and the plating uniformity problems in electroplating process have been solved.And,by the experimental research,the thin metal film low temperature deposition and patterning process parameters and the non-metallic film etching process parameters have been optimized.Finally,by these key fabrication processes,the 640×480 micro-bolometer array which used the SiGe/Si multi-quantum well materials have been fabricated.Then,the micro-bolometer array have been tested,and to confirmed the three micro-bridge structure had well support and uniformity.The effective pixel ratio of the 35×40-U 640×480 micro-bolometer array was more than 99%.And the micro-bolometer array infrared absorption of the bands 8-14 microns was more than 90%.The resistance of micro-bridge was about 40k?.The micro-bridge temperature coefficient of resistance was more than 2.6%/K.The thermal conductivity of 40×40-L micro-bridge was 1.645×10-7W/K,the heat capacity of 40×40-L micro-bridge was 1.043 × 10'9J/K,the thermal time constant of 40×40-L micro-bridge was 7.25ms.The 35×40-U micro-bridge temperature coefficient of resistance was more than 2.6%/K.The thermal conductivity of 35×40-U micro-bridge was 1.741 ×10-7W/K,the heat capacity of 35×40-U micro-bridge was 1.383×10-9J/K,the thermal time constant of 35×40-U micro-bridge was 7.94ms. |
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