基于纳米玻璃粉固态填充及热再流的TGV封装基础问题研究

High density and quality TGV has a great significance to capture the underlying common key technology such as reliability and long-term stability for integration micro sensor. Micro mould and glass vacuum thermal reflow process are in vogue which are helpful attempt to fabricate TGV encapsulation, but the relative basic issue that is different plastid microscale viscous fluid change mechanism remains to be in the study of exploration for high density TGV. This project will conduct the basic research on TGV packaging process based on solid-state filling and thermal reflow of nano glass-particles, and the project is expected to explore an efficient and universal TGV encapsulation fabrication method which is for overcoming the existing TGV fabrication process defect such as complicated process, filling difficulty of micro hole/groove, low air-tightness, and large residual stress. The main research contents are as follows: Filling mechanism of complicated micro structure based on solid-state nano glass-particles and mediator; Formability mechanism and interaction law of nano glass-particles thermal reflow in micro structure with different basement materials; Process compatibility of nano glass-particles thermal reflow, stress evolution law of the packaging structure, and design, fabrication, test the packaged ultramicro vacuum resonator. The project aims to establish process route of fabrication and homogeneous filling for pure nano glass-particles; master the control method of nano glass-particles thermal reflow with lower stress; verify the process compatibility. On this basis, optimization methods of reducing packaging residual stress and improve the output stability of micro devices will be presented.

实现高密度、高质量TGV对攻克集成化微传感器的可靠性和长期稳定性等共性关键技术具有重大意义。新兴的微模具和玻璃片真空热回流等工艺是制备TGV封装的有益尝试，但是面向高密度TGV的异质体微尺度黏滞流变机制等基础科学问题仍有待于进一步探索研究。本项目将围绕现有TGV技术的工艺复杂、微孔/槽填充难、气密性差、残余应力大等共性缺陷，开展基于纳米玻璃粉固态填充及热再流技术的TGV封装工艺基础研究，旨在建立高效、普适的TGV封装制备方法。探索中介物辅助纳米玻璃粉填充复杂微结构的机理，建立高纯度纳米玻璃粉制备及致密填充工艺路线；阐明微结构内纳米玻璃粉热再流成型成性机制以及与不同基底相互作用规律，掌握纳米玻璃粉低应力热再流调控方法；研究纳米玻璃粉热再流工艺兼容性和封装结构的应力演变规律，设计制作并测试被封装真空超微谐振器，验证工艺兼容性，并在此基础上提出降低残余应力、提高输出稳定性的优化方法。

本项目围绕现有TGV制备技术存在的工艺复杂、微孔/槽填充难、残余应力大等共性缺陷，开展了基于纳米玻璃粉固态填充及热再流技术的TGV封装工艺基础问题和关键技术研究。研究了固态纳米玻璃粉末填充复杂微结构的机理和方法，建立了高纯度纳米玻璃粉制备及致密均匀填充的工艺路线；研究了异质微结构内纳米玻璃粉热再流成型成性机制和调控方法，建立了纳米玻璃粉低应力热再流的工艺路线；验证了纳米玻璃粉热再流技术的封装工艺兼容性和可行性，可以开展圆片级批量工艺制造，为TGV封装技术的实用化夯实理论基础。研究过程得到的重要结论包括：.（1）通过正交试验，获得纳米玻璃粉末制备的较优工艺条件为：卧式行星磨罐体积0.5L，填充率20%，球料比20:1，球磨机转速600r/min，球磨时间14h，纯水添加量30mL，此种工艺条件下粒度小于1μm的玻璃粉末粒度分布占比求和可达95.599%；.（2）通过优化粉末状态和烧结参数，获得较好玻璃粉末热熔回流效果的工艺参数，烧结后玻璃体透明且无裂痕的工艺条件是粉末、水和氢氧化钠的质量比为1:1:0.2、高温保温温度1000℃、保温3h且保温阶段抽真空1h，烧结后玻璃体不透明但玻璃和硅基底都无裂痕的工艺条件是粉末、水和硼砂的质量比为1:1:0.3，高温保温温度为1000℃、保温5h；.（3）项目开发的纳米玻璃粉热再流技术能够较好兼容清洗腐蚀、机械减薄、化学机械抛光、光刻、干法刻蚀、金属溅射等传统MEMS工艺，可以开展圆片级批量工艺制造；.（4）项目设计并制备的谐振器工作在真空环境下时可获得1万以上的Q值，谐振频率在18kHz左右，可用于验证本项目提出的TGV封装；.（5）项目建立了稳定时间、稳定性波动、稳定性变化量三个MEMS器件稳定性评价指标，评价了疲劳脉动、冷热循环和振动时效三种方法对MEMS器件稳定性提升的效果，为MEMS谐振器稳定性提升试验方法提供了良好的应用借鉴。