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Measurement of Mechanical Properties of a Thermally Evaporated Gold Film Using Blister Test

블리스터 시험법을 이용한 열증착 금박막의 기계적 성질 측정

  • Moon, Ho-Jeong (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Ham, Soon-Sik (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Earmme, Yun-Young (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Cho, Young-Ho (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology)
  • 문호정 (한국과학기술원 기계공학과) ;
  • 함순식 (한국과학기술원 기계공학과) ;
  • 엄윤용 (한국과학기술원 기계공학과) ;
  • 조영호 (한국과학기술원 기계공학과)
  • Published : 1996.03.01

Abstract

Mechanical properties, including Young's modulus, residual stress and rupture strength, of a thermally evaporated gold film have been measured form a blister test. In a theoretical study, the priniple of minimum potential energy and that of virtual work have been applied to the pressurized circular membrane problem, and load-deflection relations have been derived for typical membrane deflection mode of spheroidal shape. In an experimental study, circular gold membranes of 4800 A-thickness and 3.5mm diameter were fabricated by the silicon electropolishing technique. Mecahnical properties of the thin gold films were deduced from the load-deflection curves obtained by the blister test, Young's moduli, obtianed from blister test, have been in the range of 45-70 GPa, while those of bulk gold have been in the range of 78-80 GPa. Residual stresses in the evaporated gold films have been measured as 28-110MPa in tension, The rupture strength of the gold film has turned out to be almost equal to that of dental gold alloy (310-380MPa). It has been demonstrated that the present specimen fabrication method and blister test apparatus have been effective for simultaneous measurement of Young's modulus, residual stress and repture strength of thin solid films. Especially, the electropolishing technique employed here has provided a simple and practical way to fabricate thin membranes in a circular or an arbitrary shape, which could not be obtained by the conventional anisotropic silicon mecromachining technique.

Keywords

Blister Test;Evaporated Gold Film;Residual Stress;Youngs Modulus;Rupture Strength;Electropolishing Precess