芯片级铷原子气室的制备

Fabrication of chip-scale alkali metal cells

本文设计了一套技术方案,用于制备量子传感仪表的核心物理组件芯片级铷原子气室,工艺流程包括微小型硅孔容器制备、叠氮化铷(Rb N3)填充、晶圆级气密封装,以及叠氮化铷光照分解等.利用阳极键合技术,通过改进的玻璃/硅片/玻璃三层晶圆气密封装工艺完成了芯片级铷原子池的封装制备.为实现玻璃/硅片/玻璃三层晶圆键合,在完成玻璃/硅片两层晶圆键合后,采用倾斜角度溅射的方法在玻璃/硅片键合结构的背面(即玻璃一面)和侧边镀制了一定厚度的Al金属膜,将电学接触引导至硅片,然后进行第二次阳极键合,以此获得高质量的玻璃/硅片/玻璃三层键合结构.通过显微镜、芯片剪切力测试和He检漏仪等手段对键合结构进行检测分析表明,三层键合结构的两个键合截面均具有良好的键合强度,键合结构的气密性优于2.5×10-8Pa·m3·s-1.完成气密封装后,采用光辐照分解的方法使腔室中的Rb N3分解成Rb和N2,获得了以N2作为缓冲气体的铷原子池.通过透射光谱表明Rb有效地存在于腔室之中,证明了该工艺方案对制备芯片级碱金属原子气室是简便可行的.

The fabrication processes of chip-scale alkali atom vapor cells are designed, which include silicon micromachining, filling arrays of miniaturized cells with rubidium azide, hermetic packaging using anodic bonding technology, and photodecomposition of rubidium azide. The improved anodic bonding technology is demonstrated and used to improve the gastight bonding of alkali atom vapor cells to the glass/silicon/glass bonding structure.After the anodic bonding of the glass and silicon wafer is finished, an Al metal film with a certain thickness is sputtered at a certain angle at the back（i.e., the glass side） and side of the glass/silicon-bonded structure.Therefore, the electrical contact is led into the silicon wafer when a second anodic bonding is performed, and a high-quality glass/silicon/glass bonding structure is realized. Such anodic structures have great bond strength and gastight bonding of as low as 2.5×10^-8Pa·m3·s^-1. After gastight sealing, the cells are irradiated with ultraviolet, causing the azide to photodissociate into pure rubidium and nitrogen in situ. Rubidium optical absorption spectrum indicates that rubidium atoms are effectively sealed in the cells. It is confirmed that the process for the fabrication of the chip-scale alkali atom vapor cells is simple and feasible.