Abstract-Ultra-thin dies are difficult to package because of their fragility and flexibility. Current ultra-thin die integration technology for 3D microsystems relies on robotic pick-andplace machines and machine vision, which has rather limited throughput for high-accuracy assembly of fragile ultra-thin dies. In this paper, we report a hybrid assembly strategy that consists of robotic pick-and-place using a vacuum microgripper, and droplet self-alignment by capillary force. Ultrathin dies with breakable links are chosen as part of the assembly strategy. Experimental results show that we can align ultra-thin (10µm) dies with sub-micron accuracy without machine vision. A fully automatic sequence of stacking several of these dies is demonstrated. Up to 12 ultra-thin dies have been stacked. These early results show that die-to-die integration of ultra-thin dies with higher throughput than the current industry robot is possible by applying both robotic handling and droplet self-alignment to ultra-thin die assembly.

The evaluation of plane-plane contact force has become a big issue in micro-/nano research, for example in microassembly. However with the lack of effective experimental equipments, the research on plane-plane contact has been limited to theoretical formulations or virtual simulation. In this paper, a microforce sensor and precision parallel robot integrated system is proposed for the microforce measurement of plane-plane contact. In the proposed system, the two objects are fixed on the parallel robot end-platform and the microforce sensor probe tip, respectively, and the high precision robot system is employed to provide six degree-of-freedom motions between both objects. So it is convenient for the microforce measurement between the planar objects with different orientations. As a significant application, the proposed system is utilized for measurements of pull-off force between planar objects, in which the validation of the system is demonstrated in practice. The proposed microforce measurement system is generic, which can be extended to a variety of microforce measurements in plane-plane contact.