High Curvature Bending of Ultra-Thin Chips and Chip-on-Foil Assemblies

D. van den Ende[1]
[1]Holst Centre / TNO, Eindhoven, The Netherlands

Ultra-thin chips of less than 20µm become flexible, allowing integration of silicon IC technology with highly flexible electronics. This combination allows for highly intelligent products of unprecedented thinness, flexibility and cost. Examples include sensor systems integrated into food packaging or healthcare and sport monitoring tags as wearable patches or even directly in clothing textile [1]. During use the ultra-thin chips in these products can be bent to a very high curvature, sometimes to less than 1mm bending radius, which puts a large strain on the chips (see figure 1). In this paper the strength of ultra-thin chips at very high curvatures is evaluated, using a modified four-point bending method (see figure 2).