阳极键合用高分子固体电解质的性能研究

Properties of Solid Polymer Electrolyte for Anodic Bonding

根据微机电系统(MEMS)封装中常用的阳极键合技术的特点,采用机械合金化法制备了高分子固体电解质,用作新的阳极键合材料。采用傅里叶红外光谱(FTIR)、X射线衍射(XRD)和同步辐射小角X射线技术(SAXS)等手段研究了锂盐加入量对络合成的阳极键合用聚氧乙烯(PEO)LiX的导电性能的影响,进而探讨了高分子固体电解质作为新型封装材料在阳极键合应用中的可行性。结果表明:相对于LiPF6,络合LiClO4更容易增加锂离子的迁移数,能更有效地阻碍高分子固体电解质的结晶,使得无定形区的含量增加;对于制备出的阳极键合用PEO-LiClO4高分子固体电解质材料,随着锂盐含量的增加,PEO与锂盐之间的络合结构变得更松弛,该络合体系的有序性变差,无序度增大,这种结构在静电场作用下更容易破坏,因而电导率更高,键合质量良好。

Anodic bonding is a common method used in MEMS packaging. In this study, the mechanical alloying was adopted to prepare the solid polymer electrolyte as the new anodic bonding material according to the features of anodic bonding technology. The conductive behaviours of different contents of PEO-LiX for anodic bonding were analyzed by means of Fourier infrared spectroscopy （FTIR）, X-ray diffraction, and small angle X-ray synchrotron radiation technology （SAXS）. Then the feasibility of the solid polymer electrolyte applying as a new type of packaging material in anodic bonding was discussed. The results show that the complex LiClO4 is easier to increase the transference number of the lithium ions compared with LiPF6, and can prevent the crystallization of the solid polymer electrolyte more effectively to increase the content of amorphous region. The study also finds that, with the increase in lithium content, the complex structure between PEO and lithium salt becomes looser, the degree of disorder increases, and this structure can he destroyed more easily by the action of electrostatic field, leading to a higher conductivity and better bonding quality.