Microstructure Size measurement based on c-scan image of scanning acoustic microscopy

The scanning acoustic microscopy system has a poor lateral resolution in the scan of micro-defects within micro-devices. To solve the problem, this paper identifies the main influencing factors of the lateral size measuring accuracy of scanning acoustic microscopy, namely, C-scan image resolution and the lateral size measuring resolution. Then, the two kinds of resolutions were subjected to detailed analysis. After that, several micro-scale silicon wafers were prepared, and subjected to defect detection and size measurement by a high-frequency scanning acoustic microscopy system with a 300MHz high-frequency focused transducer. The measuring results show that the C-scan of the scanning acoustic microscopy system successfully recognized linear defects of 10μm and circular defect with a diameter of 16μm, and achieved a size measuring error no greater than 5.05 %; in addition, the measuring error is negatively correlated with the size of the wafer. Thus, the scanning acoustic microscopy system can measure small dimensions in an accurate manner.