薄膜機械特性及殘留應力之反算偵測(1/3)

Nondestructive determination of Young’s modulus, coefficient of
thermal expansion, Poisson ratio, and thickness of a thin film has long
been a difficult but important issue as the film of micrometer order thick
might behave differently from that in the bulk state. In this report,
we have successfully demonstrated the capability of determining all these
four parameters at one time. This novel method includes use of the
digital phase-shifting reflection moiré (DPRM) technique to record the
slope of wafer warpage under temperature drop condition. In the
experiment, 1-um thick aluminum was sputtered on a 6-in silicon wafer.
The convolution relationship between the measured data and the mechanical
properties was constructed numerically using the conventional 3D finite
element code. The genetic algorithm (GA) was adopted as the searching
tool for search of the optimal mechanical properties of the film.