| 학회 | 한국재료학회 |
| 학술대회 | 2008년 봄 (05/22 ~ 05/23, 상록리조트) |
| 권호 | 14권 1호 |
| 발표분야 | 제 14회 신소재 심포지엄 - 故김기배 박사 추모 심포지엄 |
| 제목 | Evaluation of elastic moduli of multi-layered thin films on polymer substrates using wrinkling analysis |
| 초록 | Multi-layered thin films on soft substrates are increasingly used in device applications such as flexible electronics. Since it is well known that the mechanical properties of thin films can be quite different from those of bulk materials, research engineers in the N/MEMS industry need to know the mechanical properties of thin films used in their devices for the purpose of reliability and performance estimation. The mechanical properties of a single-layer thin film on a substrate are readily measured using nanoindentation if film and substrate have similar properties. The technique has severe problems, however, when applied to stiff films on compliant substrates, a situation often encountered when dealing with flexible electronics. Moreover, the technique is not capable of measuring the mechanical response of the individual layers in a multi-layered thin-film system because the indentation response of a multi-layered system is not a simple sum of the responses of the individual layers. Clearly, there exists a need for a technique capable of measuring the mechanical properties of thin films on compliant substrates and of individual layers in multilayered systems. One such technique relies on an analysis of the wrinkling patterns that develop in thin films on polymer substrates. When a stiff film on a compliant substrate is subjected to a compressive stress, the large elastic modulus difference between film and substrate allows the film to relieve the compressive stress by wrinkling. The period of the wrinkles is directly related to the stiffness mismatch between film and substrate. Ti, Cu and Cu/Ti film stacks have been deposited polydimethylsiloxane (PDMS) substrates by means of DC magnetron sputtering. Wrinkle patterns developed as a result of the uni-axial compressive stress in the film stacks. The wrinkling pattern of the film stacks is analyzed and the elastic moduli of the individual films are extracted with knowledge of the wrinkling wavelengths and film thicknesses. |
| 저자 | 한준현1, 문명운1, 지광구1, 한승희1, Joost J. Vlassak2 |
| 소속 | 1한국과학기술(연), 2Harvard Univ. |
| 키워드 | elastic modulus; residual stress; wrinkling; Cu film; PDMS |
