Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, China.
Lab Chip. 2011 Apr 21;11(8):1532-40. doi: 10.1039/c0lc00708k. Epub 2011 Mar 8.
A novel foaming process-chemical foaming process (CFP)-using foaming agents to fabricate wafer-level micro glass cavities including channels and bubbles was investigated. The process consists of the following steps sequentially: (1) shallow cavities were fabricated by a wet etching on a silicon wafer; (2) powders of a proper foaming agent were placed in a silicon cavity, named 'mother cavity', on the etched silicon surface; (3) the silicon cavities were sealed with a glass wafer by anodic bonding; (4) the bonded wafers were heated to above the softening point of the glass, and baked for several minutes, when the gas released by the decomposition of the foaming agent in the 'mother cavity' went into the other sealed interconnected silicon cavities to foam the softened glass into cylindrical channels named 'daughter channels', or spherical bubbles named 'son bubbles'. Results showed that wafer-level micro glass cavities with smooth wall surfaces were achieved successfully without contamination by the CFP. A model for the CFP was proposed to predict the final shape of the glass cavity. Experimental results corresponded with model predictions. The CFP provides a low-cost avenue to preparation of micro glass cavities of high quality for applications such as micro-reactors, micro total analysis systems (μTAS), analytical and bio-analytical applications, and MEMS packaging.
使用发泡剂制造包括通道和气泡在内的晶圆级微玻璃腔的新型发泡工艺-化学发泡工艺（CFP）-进行了研究。该工艺包括以下顺序步骤：（1）通过在硅晶片上进行湿法刻蚀来制造浅腔；（2）将适当的发泡剂粉末放置在蚀刻的硅表面上的硅腔中，称为“母腔”；（3）通过阳极键合将硅腔密封在玻璃晶片上；（4）将键合的晶片加热至玻璃的软化点以上，并烘烤几分钟，当“母腔”中发泡剂分解所释放的气体进入其他密封的互连硅腔时，软化的玻璃会发泡成圆柱形通道，称为“子通道”，或称为“子气泡”的球形气泡。结果表明，成功地实现了具有光滑壁表面的晶圆级微玻璃腔，而没有 CFP 的污染。提出了 CFP 的模型来预测玻璃腔的最终形状。实验结果与模型预测相符。CFP 为制备用于微反应器、微全分析系统（μTAS）、分析和生物分析应用以及 MEMS 封装等应用的高质量微玻璃腔提供了一种低成本途径。
