Test And Analysis For The Thermal Conductivity Of Silicon Nitride Thin Film Prepared By PECVD

Materials’ conductive ability of heat is defined by thermal conductivity. For bulkmaterials, the thermo-physical parameters are independent from the Geometry of thematerials. Under microscale, the thermal conductivity of the film materials differsgreatly on different manufacturing conditions, and it cannot be analyzed through theclassical heat transferring theory. In addition, the internal heat dissipation becomes akey factor restricting the MEMS devices’ performance and life because of theirminiaturization. Therefore, to study the thermal conductivity of film materials is of greatimportance.In this paper, the test method of the thermal conductivity of silicon nitride thin filmbased on the microscale heat transfer theory was focused. A new test method wasdesigned. In this work, one dimensional (1-D) two-end supported cantilever beam wasprovided, which includes a metal heater (which also acts as the thermometer) andunderneath thin film for measurement.1-D heat flow equation was employed to obtainexpression of temperature rise (ΔT) distribution along the cantilever beam and voltagedrop change along the heater (ΔU) when exerting a direct current in the heater. ANSYSfinite element software was employed to simulate ΔT and ΔU. Results demonstrate thatthe simulations agree well with the theoretic calculations. The reliability and accuracyof the test structure were confirmed.The layouts of each layer were designed through L-edit software, andmicro-fabrication techniques were applied to fabricate the test structure. Finally, futurework was outlooked in the end.