表征超大规模集成电路互连纳米薄膜硬度特性的声表面波的频散特性

利用声表面波(SAW)的频散特性来表征超大规模集成电路(ULSI)互连系统中低介电常数(k)薄膜的物性具有准确、快速、对材料无损伤等突出优点.研究了Si(100)衬底上淀积低k薄膜的分层结构中，SAW沿任意方向传播的色散关系.引入坐标变换后，单层薄膜特征矩阵从9阶降到6阶，双层薄膜特征矩阵从15阶降到10阶，大幅度提高了计算速度，有利于生产ULSI过程中的在线监测. 关键词： 超大规模集成电路 声表面波 传输方向 频散特性

Dispersion feature in arbitrary direction of surface acoustic wave applied to property characterization of ultra-large-scale integrated circuit interconnect films

The ultrasonic surface acoustic wave (SAW) technique is becoming attractive for accurate and nondestructive property determination for thin low-k films employed in the modern ultra-large-scale integrated circuit (ULSI). In this paper, the dispersive characteristics of SAW propagating along arbitrary directions on the layered films deposited on Si(100) were studied in detail. The computation time was reduced greatly by appling coodinate transformation. The calculation of 9×9 Christoffel matrix was simplified to 6×6 matrix for one film layer structure, and from 15×15 matrix to 10×10 matrix for two-layered structure. This work will benefit the on-line test of low-k film properties during ULSI fabrication. Furthermore, the limitation on the propagating direction of SAW can be eliminated in the measurement.