多晶硅微构件拉伸破坏特性的测量

硅表面工艺是微型机械制造的重要工艺，而多晶硅是表面工艺中最常用的主要材料，它的力学特性直接关系到微型电子机械系统的可靠性和使用寿命，因此对其破坏特性的研究是非常有必要的。本文在概述了国外对体硅工艺和表面工艺制作的构件材料破坏特性研究情况的基础上，提出了利用旋转台对表面工艺制作的多晶硅微梁进行拉伸破坏实验的方法，并在制作的测量系统上进行了实验，得出多晶硅微梁的拉伸破坏强度大于2．0GPa。

MEASUREMENT OF THE FRACTURE PROPERTY OF POLYSILICON MICRO STRUCTURE

Surface micromachining is a key fabrication method for MEMS. Polysilicon is widely used in surface micromachining and often acts as the essential structure materials. Its fracture property has close relation with the reliability of MEMS devices. So it is indispensable to know the fracture property of polysilicon. A new method is proposed to measure the tensile fracture property of polysilicon microstructures. A spinner is used to load a tensile stress to a beam specimen. Specimens are fabricated by surface micromachining and electroplating. The specimen is a cantilever with a paddle on which nickel is electroplated to form seismic mass. When the specimen is placed along radial vector of the spinner, the centrifugal force caused by seismic mass will pull the cantilever to fracture. The tensile stress can be determined from the rotate speed, the radius placed at by the mass, the seismic mass, and the area of cantilever cross section. The measurement system includes a rotate speed detection and control circuit and a fracture detection circuit. Experiments show that the tensile strength of polysilicon is greater than 2.0 GPa. The measurement error is analyzed too. This method enables simple specimen preparation and measurement process