Adhesion in Thin Film Structures for Emerging Technologies
Reinhold H. Dauskardt
Department of Materials Science and Engineering
Stanford University, Stanford, CA 94305-2205
Debonding of interfaces and cracking of fragile thin films effects the mechanical integrity of a wide range of thin-film device structures, including microelectronic interconnects, micro-actuators, and biosensors. This results in reduced yield at all levels of device processing including survival through chemical mechanical planarization (CMP) and subsequent device packaging. Two unique challenges for emerging technologies involve the introduction of new materials and the effect of device architecture including length-scales and aspect ratios, on mechanical and fracture behavior. Materials are nearly always optimized for other desired properties (e.g. dielectric properties, diffusion resistance, corrosion protection) and the resulting effects on mechanical performance can be significant.
In this presentation, the mechanical and fracture behavior of representative blanket and patterned thin-film structures including glass and organic layers, barriers and metal layers, are examined. The acceleration of crack growth in complex chemical environments typically encountered during processing is discussed. The effects of interface parameters and thin-film composition and porosity will also be considered. Novel strategies to toughen fragile nanoporous materials using molecular remnants of the porogen molecules used to create the porosity are described. Finally, the effect of more complex patterned thin-film structures are examined where length scales are restricted in more than one dimension. Implications for device reliability, integration of new materials, and life prediction are discussed.
Reinhold H. Dauskardt: Professor and Associate Chair, Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305-2205; Ph: (415) 725-0679, Fax: (415) 725-4034, Email: firstname.lastname@example.org.
Reinhold Dauskardt is Professor and Associate Chair of the Department of Materials Science and Engineering at Stanford University. His research interests lie in the study of the relationship between microstructure and mechanical properties of advanced material systems. These include thin-film and layered structures for microelectronic devices and their packages, composites and bulk metallic glasses for structural applications, biomaterials, and soft tissues. His principal activities have concentrated on the fundamental micromechanisms of deformation, fracture and subcritical crack-growth behavior. Studies include detailed microstructural and mechanical property investigations using high resolution characterization and micromechanical testing techniques. Experimental studies are complimented with a range of multiscale computational activities involving models of deformation, fracture and debonding. Dauskardt’s research includes interaction with a wide range researchers in academia, industry, and clinical practice. He has served as editor for a number of journals and books, published over 150 articles in the scientific literature, and won a number of awards including the U.S. Department of Energy Outstanding Scientific Accomplishment Award in Ceramics and Metallurgy for innovative research on cyclic fatigue degradation in ceramics in 1989, the Alexander von Humboldt Research Award in 2002, and the ASM International Silver Medal in 2003.