Improvement of CMOS-MEMS accelerometer using post-CMOS selective electroplating technique
Improvement of CMOS-MEMS accelerometer using post-CMOS selective electroplating technique
复制标题
采用后CMOS选择性电镀技术改进CMOS-MEMS加速度计
DOI：
10.1109/transducers.2011.5969153
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
W. Fang
中科院分区：
文献类型：
--
作者：
Yu;M. Tsai;Tsung;W. Fang
本研究提出一种简单的方法来改善CMOS-MEMS电容式加速度计的性能，通过后CMOS金属电镀工艺。金属层可以在低温下选择性地电镀在MEMS结构上，并且金属层的厚度可以容易地通过工艺调节。因此，电容式加速度计的性能（即，结构变形、灵敏度）可以得到显著改善。在实际应用中，所设计的加速度计已采用（1）标准TSMC CMOS 0.35μ m2 P4 M工艺，（2）Asia Pacific Microsystems Inc.的Ti/Au种子层沉积/构图工艺实现。(apm)MEMS代工厂，以及（3）内部CMOS后电镀和释放工艺。测量表明，镀Ni后灵敏度提高了2.5倍，噪声降低了近2.5倍。此外，由于温度变化而引起的不希望的结构变形被电镀Ni显著抑制。
This study presents a simple approach to improve the performance of CMOS-MEMS capacitive accelerometer by means of the post-CMOS metal electroplating process. The metal layer can be selectively electroplated on the MEMS structures at low temperature; and the thickness of metal layer can be easily adjusted by process. Thus, the performance of capacitive accelerometer (i.e., structure deformation, sensitivity) can be improved significantly. In application, the designed accelerometers have been implemented using (1) standard TSMC CMOS 0.35µm 2P4M process, (2) Ti/Au seed-layer deposition/patterning by Asia Pacific Microsystems Inc. (apm), MEMS foundry, and (3) in-house post-CMOS electroplating and releasing processes. Measurements indicate the sensitivity is improved for 2.5-fold, and noise is decreased near 2.5-fold after Ni electroplating. Moreover, unwanted structure deformation due to the temperature variation is significantly suppressed by electroplated Ni.