| 초록 |
The current trend in the interconnect development is to incorporate polymer layers together with glass or ceramic layers to form a multilayered wiring structure. The use of polymers is, however, not without problems. One of the most important concerns is the mechanical integrity of the multilayered structures. For multilayered device, there are often reliability problems, such as displacement, cracks, and delamination at interfaces. Thermal stress cause interfacial adhesion and mechanical failures associated with interfacial residual stress due to the mismatch of physical properties between polymers and the other materials used. The mismatch in thermal expansion coefficient and the Young’s modulus will generate thermal stress in the metal/polymer structure during thermal cycling. Since thermal cycling is a typical procedure during fabrication and polymer curing, it is important to understand the mechanical properties of the metal/polymer structure, particularly the nature of stress relaxation during thermal cycling. Due to volatilization of different volume by-products during curing process, the morphological structure and chain rigidity of polyimide thin films can be changed. For this study, a computer-controlled experiment has been set up to measure the thermal stress of multilayered films using the bending wafer technique. To understand and classify these phenomena, the bending beam technique for thermal stresses kinetics according to Imidization history and thermal cycling in polyimide thin films prepared from various precursors was used.
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