The constitutive relation of Skorohod and Olevsky for viscous sintering is utilized to model the shrinkage and relative density evolution during the sintering process of ceramics. A new implicit integration scheme is presented and implemented. The computational cost is drastically reduced by combining this integration scheme with a solid-like shell element formulation, which also enables a faster and more accurate description of shape distortions, especially for thin geometries. The characterization and identification of the material viscosity is also improved via the Aquilanti–Mundim deformed Arrhenius description. The model robustness is examined with a spectrum of benchmark tests: ZnO sintering experiments from previous studies, as well as new lanthanum tungstate sintering tests. The model predictions for both dimensional shrinkage and relative density evolution are very accurate using the newly proposed material viscosity functions. The model improvements offer the possibility to simulate long-time sintering processes with higher accuracy and significantly reduced computational efforts.@en

The exciting field of stretchable electronics (SE) promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects with micron-scale footprints, which calls for proven standardized (complementary metal-oxide semiconductor (CMOS)-type) process recipes using bulk integrated circuit (IC) microfabrication tools and fine-pitch photolithography patterning. Here, we address this combined challenge of microfabrication with extreme stretchability for high-density SE devices by introducing CMOS-enabled, free-standing, miniaturized interconnect structures that fully exploit their 3D kinematic freedom through an interplay of buckling, torsion, and bending to maximize stretchability. Integration with standard CMOS-type batch processing is assured by utilizing the Flex-to-Rigid (F2R) post-processing technology to make the back-end-of-line interconnect structures free-standing, thus enabling the routine microfabrication of highly-stretchable interconnects. The performance and reproducibility of these free-standing structures is promising: an elastic stretch beyond 2000% and ultimate (plastic) stretch beyond 3000%, with <0.3% resistance change, and >10 million cycles at 1000% stretch with <1% resistance change. This generic technology provides a new route to exciting highly-stretchable miniature devices.@en