测量深亚微米薄膜内微小残余应力的测试圆环结构

Measurement of ultra small residual stress in deep submicron thick films by the annular thin plates

为能灵敏地测出深亚微米薄膜中的微小残余应力,对现有的圆环临界屈曲结构做进一步改进,并利用改进后的圆环结构测量3种不同厚度的深亚微米尺度薄膜残余应力。通过在线监测系统对释放过程进行观察并测量其临界腐蚀深度,然后借助ANSYS软件的特征值屈曲法计算出残余应力大小。改进后的测试圆环结构最终成功地测量出3种深亚微米尺度薄膜中10MPa以下的微小残余压应力,而制作在同一薄膜上的微旋转机构因在如此低的应力状态下未发生明显的形变而未能实现残余应力的测量。

In order to sensitive measure the small residual stress in deep submicron thick films, some improve- ment have been made on the annular structures, three deep submicron films of various thickness were prepared to measure the residual stress with this improved annular structures, and released in HF solution to get the crit- ical etching length under an on line monitoring system. The critical etching length was inputted into the ANSYS software to predict the residual stress by the eigenvalue buckling analysis. Small compressive stress less than 10MPa within films were resolved successfully with this improved annular structure, hut the micro rotating structures fabricated in the same die cannot generate a distinguishable deformation and failed to measure the re- sidual stress.