| 초록 |
Recently, most high performance microelectronic devices demand multi-layered structures to be dense and compact. 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 layers in addition. Polyimides are formed from their corresponding various precursors : polyamic acid or polyamic ester precursor. Due to volatilization of different volume by-products during curing process, the morphological structure and chain rigidity of polyimide thin films can be changed. In addition, because of the nearness of the curing system to it*s glass transition temperature, all the chain relaxation associated with volatilization may occur prefectly. These may appear as imperfections in the stacking efficiency of the fully cured polyimide thin films. This study is to demonstrate that thermal stresses behaviors in different polyimide thin films depends on the degree to which the polyimide backbone structure can accommodate the thermal expansion changes that occur during cure and how these processes affect the alignment or packing order of the rigid polyimide chains into perhaps a fringed micelle-like configuration[1,2]. To understand and classify these phenomena, the bending beam technique for thermal stresses kinetics in different backbone structure polyimide thin films prepared from various precursors was used. By using FT-IR technique, the effect of different precursors on the morphology transition in polyimide thin films was investigated.
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