کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5202469 1381900 2013 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effects of mechanical stresses, thickness and atmosphere on aging of polyimide thin films at high temperature
ترجمه فارسی عنوان
تأثیر تنش های مکانیکی، ضخامت و جو در پیری فیلم های نازک پلی امید در دمای بالا
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
چکیده انگلیسی

This work deals with the isothermal aging mechanisms and their impact on the behaviour of polyimide thin films, usually used as dielectric material in high temperature electronic applications. The objectives were to achieve a better knowledge of the atmosphere and mechanical stress effects on the degradation mechanisms of deposited thin films during high temperature isothermal aging. Hence, BPDA/PDA aromatic polyimide (PI) thin films deposited on two different substrates (stainless steel and silicon) were aged slightly below their glass transition temperature (0.8 Tg) in air and in nitrogen atmospheres. During the aging, the dielectric strength, morphological characteristics (thickness, surface profile) and chemical variation were monitored for different initial film thicknesses (<10 μm). Results show that films aged under nitrogen and those deposited on silicon substrates aged in air do not show any remarkable degradation during the aging period. In contrast, the films deposited on stainless steel substrates present significant degradation during aging in air and the material lifetime is thickness dependent. In the latter conditions, the measured mean thickness losses for long aging periods are about 0.5 nm/h for all initial thicknesses, indicating that the degradation is not related to the bulk variation of the material but to a surface degradation mechanism. In addition, the breakdown field presents stabilization after an initial aging period, leading us to conclude that the bulk of the material is not affected by the aging. The coupled results indicate that the BPDA/PDA thermal degradation mechanism at temperature below its glass transition one is due to the attack on the outer film layer, related to the presence of oxygen in the atmosphere and strongly dependent on thermo-mechanical substrate properties. Hence, studying of the thermo-oxidative stability of freestanding polyimide films can lead to misestimated reliability.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer Degradation and Stability - Volume 98, Issue 1, January 2013, Pages 361-367
نویسندگان
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