Nondestructive Determination of Young's Modulus of Interconnecting Thin Films by a Broadband Surface Acoustic Wave‐Interdigital Transducer. Issue 4 (18th January 2023)

• Record Type: Journal Article
• Authors: Zhang, Li; Xiao, Xia; Qi, Haiyang; Zhang, Jinsong; Huang, Yiting
• Is Part Of: Physica status solidi. Volume 17:Issue 4(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-18
• Subjects: dispersion curves -- nondestructive testing -- surface acoustic wave-interdigital transducers -- thin films -- Young's moduli; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202200431
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : A facile and rapid method for nondestructive testing (NDT) of the Young's modulus of interconnecting thin films using a broadband surface acoustic wave‐interdigital transducer (SAW‐IDT) is presented herein. A linear periodic SAW‐IDT with 20–125 MHz is designed and fabricated to excite surface acoustic wave (SAW) signals on the samples. By applying burst excitations under different frequencies, the SAW waveforms are picked up by a miniaturized piezoelectric transducer and processed by slant stack transformation. Consequently, the SAW dispersion curves over a wide frequency band are established to match the film parameters. Young's modulus of the 100 and 300 nm thickness of SiO2 films and the 800 and 1500 nm low‐ k polyimide (PI) films is characterized. The nanoindentation method, as a control experiment, is also carried out to verify the accuracy of the SAW method, and the test results show that the SAW method can eliminate the effect of the substrate with higher precision. This work shows the advantage of the NDT technique by SAW‐IDT in measuring the Young's modulus of ultrathin films with low cost, controllable frequency range, and high accuracy. Abstract : A linear‐periodic broadband surface acoustic wave‐interdigital transducer (SAW‐IDT) with 20–125 MHz is used to characterize the Young's modulus of thin films. The SAW signals are picked up under burst excitation at different frequencies and processed by slant stack transformation. The SAW dispersion curves over the wide frequency band are established to match the film parameter.