Application of Ni electroplating techniques towards stress-free microelectromechanical system-based sensors and actuators
Application of Ni electroplating techniques towards stress-free microelectromechanical system-based sensors and actuators
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镍电镀技术在无应力微机电系统传感器和执行器中的应用
DOI：
10.1243/0954406jmes231
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Matovic
中科院分区：
文献类型：
--
作者：
J. Matovic
摘要双材料悬臂梁是微传感器和微执行器中的常用材料。双材料元件由具有不同物理性质和/或在不同条件下沉积的两层材料组成。由于这个原因，各种来源的机械应力出现沿着层和它们之间，引起悬臂的初始变形。此外，双材料悬臂梁对外部刺激的最佳响应的必要条件是两层的杨氏模量近似相等。在实践中通常遇到的基于热致动器的致动器中，第一层通常由SiO2、PolySi或SiNx制成，而第二层由Al或Au制成。这些材料的杨氏模量显著不同，因此难以实现最大灵敏度。为了确保自由悬臂的平面性，在制造过程中的共同目标是在两个层内获得低内应力，这有时在高温工艺中代表严重的技术限制。提出了一种双材料悬臂梁层间应力补偿的新方法。SiO2、PolySi或SiNx仍用于第一层，而镍用于第二层。与以前使用的铝和金相比，镍具有许多优点和有利的机械性能。
Abstract The bimaterial cantilevers are frequently used in microsensors and microactuators. A bimaterial element consists of two layers of materials with different physical properties and/or deposited under different conditions. For this reason, mechanical stresses of various origins appear along the layers and between them, causing initial deformation of the cantilever. Further, a necessary condition for the optimum response of a bimaterial cantilever to an external stimulus is that Young's moduli of both layers are approximately equal. In thermal cantilever-based actuators commonly met in practice, the first layer is usually made of SiO2, PolySi, or SiNx, whereas the second is made of Al or Au. The Young's moduli of these materials differ significantly and thus the maximum sensitivity is difficult to achieve. To ensure the planarity of the free cantilever, the common goal during fabrication is to obtain low internal stresses within both layers, which sometimes represent a severe technological limitation in high-temperature processes. This work presents a new method of stress compensation between the bimaterial cantilever layers. SiO2, PolySi, or SiNx are still used for the first layer, whereas nickel is used for the second layer. Nickel has many advantages and favourable mechanical properties compared with previously used aluminium and gold.