Young's Modulus Detection for the Low-k Film by Laser-Generated SAWs

Advances of laser have opened new possibilities in the field of detection. The technology of laser-generated surface acoustic waves (LSAWs) is one of the applications of laser. According to the thermal-elastic theory, surface acoustic waves (SAWs) could be generated through rapid heating and subsequent expansion of the surface layer when the laser pulse irradiates on the surface of sample. The abundant information of sample surface could be obtained by testing and analyzing the SAW waveforms. The SAWs are dispersive when the waves propagate on the layered film structure. The Young's Modulus (E) of the film can be determined accurately and conveniently by matching the experimental dispersion curve with the theoretical curves. An experimental system is constructed to detect the E value of a low-k film which is deposited on the silicon (100) substrate by the method of LSAWs.