Preparation Of Metallic Interconnected Thin Films And Study Of Their Properties

In this thesis, we prepare metallic thin film by evaporation means to realize the interconnection in Micro Electro Mechanical System technology. In the process of MEMS fabrication, generally, we need connect the sensor part with that of circuit control, that is there is necessary to prepare metallic film (such metals like Cu,Al,Ni, etc.) as interconnecting poles to realize the interconnection between the upper structures and the lower ones. The performance of those interconnecting metallic poles can influence the MEMS devices'service behavior directly. In this thesis, we place emphasis on the preparation of metallic interconnecting film, furthermore, discuss and analyze the experimental results. Results show that thin film prepared by ion beam reactive sputtering and electron beam evaporation can perfectly meet the demand of interconnection in the fabrication of uncool infrared focal plane array. The thesis focus on the following four parts: (1) Prepare metallic thin film by evaporation means to realize the interconnection in MEMS technology. The process of preparation divides into two parts. Firstly, deposit a layer of metallic thin film by ion beam reactive sputtering as the buffer layer, function enhance the adhesion between the thick film and substrate; then the interconnecting metallic film is prepared by electron beam evaporation. Lift-off technique has been adopted to prepare interconnecting poles for avoiding any damage to the figure outline and the lower materials during wet erosion. Three different lift-off layers by using AZ5214 photoresist, ZKPI-305IID non-photosensitive polyimide and ENPI photoresist are investigated. Ni poles arrays to implement the interconnection were fabricated with three different types of lift-off layers. The results show that the metallic poles height are 1.86μm, 2.0μm and 1.7μm, respectively, with AZ5214, ZKPI-305IID and ENPI as lift-off layers accordingly. Characteristics of the three lift-off layers are compared, the experimental results show that they all can meet the demand of interconnection, and the one by using ENPI photoresist has the best performance. (2)Profilometer,Atomic Force Microscope and X-ray Diffraction(XRD) have been used to study the thin film's thickness, stress, morphology and construct. Factors that affect the thin film's performance are discussed. It focus on two parts. Firstly, factors in the process of ion beam reactive sputtering; secondly, factors in the process of electron beam evaporation and thermal treatment. (3)Using finite element analysis means simulate the therm-stress generated in the process of preparation of thin film. Computer simulative results and experimental ones conform well. Deduce theoretically the distributions of heat and therm-stress during the preparation. Provide a new clew in designing techniques of thin film's preparation by finite element analysis before the preparation. (4)The interconnecting performance of metallic interconnecting poles are investigated. Scheme testing the interconnecting performance has been made, and furthermore, testify the interconnecting function though experiments.