| The getter is an important compositing factor to maintain the vacuum level and improve the performance,life time and stability of MEMS devices packaged in vacuum.Due to the low capacity,the uncontrollable gettering performance and the packaging way of pre-activating with long time of current film getters,the bulk manufacturing of MEMS under the miniaturization trend is restricted.Therefore it is proposed in this paper a principle method utilizing 3D nano-scaffolds structure combined with activation by micro-area-induction-heating to realize the fabrication and application of getters with high performance.Centering on these qualitative analysis of non-evaporable getter testing system design,preparation and morphology control of 3D nano-scaffolds,fabrication of 3D nano-scaffolds Ti-film getter,heat transfer performance test and corresponding getters for 3D Nano-Scaffolds,we finally obtained a 3D nano-Scaffolds getter that has better performance of inspiration and also can achieve micro-zone induction-heating-activation in this paper.The specific research work includes the following sections:(1)We came up with a compounding principle that based on the constant volume method and the constant pressure method.And according to this,we designed a non-evaporable getter testing system based on induction heating activation principle.The ultimate vacuum that the system can achieve was 9.8×10-4Pa,the working pressure was 4.5 × 10-1Pa,and the leakage rate was 8.71 × 10-5Pa·L/s.The minimum capacity that can be detected was 0.01Pa·L,inspiratory rate was 10-4 Pa·L/s.(2)With two methods of directional electrocrystallization and anodizing,two kinds of 3D nano-scaffolds—nickel-based tower-like nanostructures and porous alumina structure—were made,and the rule of size control was obtained.We also defined that the bottom diameter of nickel-based tower-like nanostructures was 350?420nm,the height was 650?712nm,and that about 350nm of porous alumina pore size were intented to be the getter bracket size.The preparation of the two structures layed the foundation for the preparation of 3D nano-scaffolds getters with high performance.Considering that most of the MEMS packaging processes needed to be performed on silicon substrates,the above two kinds of 3D nanoscaffolds were made on a silicon substrate.Combining the preparation process of Ti-based getter and investigating the coordination relationship between the Ti film deposition morphology and the support structure,we determined a more reasonable Ti film deposition thickness.(3)Taking into account the activation of getters,we researched on the induction heating and heat transfering parameter of two kinds of 3D nano-scaffolds and we got the heat transfering effect of 3D nano-scaffold.The results show that with the influence of the enhancement of phonon scattering effect,the scale of micro-nano can lead to the decline of heat conduction coefficient and thermal diffusion,which can be conducive to heat preservation after getter induction heating.(4)Carrying on the BET surface area test on porous alumina holder,nickel-based tower-like nanoscaffolds and two-stage nickel-based tower-like nano-scaffold,we acquried that the surface area was respectively 35.632 m2/g,6.435 m2/g,7.914m2/g,and also verified that these 3D nano-scaffold getter have a higher specific surface area.Thermal Gravimetric Analyzer(TGA)testing of Ti-based getters for different 3D nano-scaffold showed the two-stage nickel-based tower-like nano-scaffold getter had the best performance,whose inspiratory capacity was 2.72395mg and rate was 6.9 X 10-4mg/(s·g),while the porous alumina holder getter has a lower gettering performance.Comprehensive comparison shows that due to the large specific surface area and ferromagnetic properties of nickel-based tower-like nano-scaffolds getters prepared in this paper,it has the dual advantages of superior inspiratory performance and induction heating activation. |
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