Film thickness dependent microstructural changes of thick copper metallizations upon thermal fatigue. Issue 11 (13th June 2017)

• Record Type: Journal Article
• Authors: Bigl, Stephan; Trost, Claus O.W.; Wurster, Stefan; Cordill, Megan J.; Kiener, Daniel
• Is Part Of: Journal of materials research. Volume 32:Issue 11(2017)
• Page Start: 2022
• Page End: 2034
• Publication Date: 2017-06-13
• Subjects: texture, -- fatigue, -- thermal stresses; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1557/jmr.2017.199
• Languages: English
• ISSNs: 0884-2914

Abstract

Abstract: Abstract : With increasing performance requirements in power electronics, the necessity has emerged to investigate the thermo-mechanical behavior of thick Cu metallizations (≥5 µm). Cu films on rigid substrates in the range of 5–20 µm were thermally cycled between 170 and 400 °C by a fast laser device. Compared to the initial microstructures, a texture transition toward the {100} out-of-plane orientation with increasing film thickness was observed during thermo-mechanical cycling, along with an abnormal grain growth in the {100}-oriented grains and a gradual development of substructures in a crystallographic arrangement. Compared to the well-studied thin Cu film counterparts (≤5 µm), the surface damage showed a 1/ h f dependency. Transition from an orientation independent ( h f = 5 µm) to an orientation specific thermo-mechanical fatigue damage ( h f = 10, 20 µm) was observed following a higher damager tolerance in {100} oriented grains.