Hybrid Microassembly with Surface Tension Driven Self-alignment: Handling Strategies and Microfabricated Patterns

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Bo Chang Name of the doctoral dissertation Hybrid Microassembly with Surface Tension Driven Self-alignment: Handling Strategies and Micro-fabricated Patterns Publisher School of Electrical Engineering Unit Department of Automation and Systems Technology Series Aalto University publication series DOCTORAL DISSERTATIONS 117/2013 Field of research Control Engineering Manuscript submitted 18 April 2013 Date of the defence 23 August 2013 Permission to publish granted (date) 14 June 2013 Language English Monograph Article dissertation (summary + original articles) Abstract Hybrid microassembly combines self-assembly technology with traditional robotic pick-andplace technology or other robotic feeding mechanics to construct microsystems. In a typical hybrid microassembly process, a micro part is brought adjacent to the assembly site by a robot handling tool at a high speed but with a relatively low precision, and liquid droplets dispensed by a dispenser at the assembly site align the part at a higher precision. By combing both the robotic pick-and-place technique and self-assembly technique, hybrid microassembly technique can achieve high speed and high precision simultaneously.Hybrid microassembly combines self-assembly technology with traditional robotic pick-andplace technology or other robotic feeding mechanics to construct microsystems. In a typical hybrid microassembly process, a micro part is brought adjacent to the assembly site by a robot handling tool at a high speed but with a relatively low precision, and liquid droplets dispensed by a dispenser at the assembly site align the part at a higher precision. By combing both the robotic pick-and-place technique and self-assembly technique, hybrid microassembly technique can achieve high speed and high precision simultaneously. This thesis explores the adaptability of hybrid microassembly technique by investigating different hybrid microassembly methods and different types of the patterns. Three hybrid microassembly approaches have been investigated: 1) droplet assisted hybrid microassembly, 2) water mist induced hybrid microassembly and 3) hybrid microassembly with forced wetting. The droplet assisted hybrid microassembly has been studied using patterns with segments and patterns with jagged edges. Parallel microassembly of microchips with water mist induced hybrid microassembly has also been explored. Hybrid microassembly on hydrophobic receptor site with super-hydrophobic substrate has been experimentally investigated with two forced wetting techniques. Four different types of patterns have been investigated for hybrid microassembly technique: (a) oleophilic/phobic patterns, (2) hydrophobic/super-hydrophobic patterns, (3) segmented patterns and (4) patterns with jagged edges. Hybrid microassembly has been studied on a new patterned oleophilic/oleophobic surface using adhesive droplet in ambient air environment. A patterned hydrophobic/super-hydrophobic surface has also been investigated and hybrid microassembly has been demonstrated with both water and adhesive. Application relevant patterns such as segmented patterns and patterns with jagged edges have been investigated. In summary, this thesis shows that hybrid microassembly can adapt to large varieties of patterns. Several new hybrid microassembly methods are developed and demonstrated. Such a wide adaptability and a variety of the processes indicate that hybrid microassembly can be a very promising approach for many potential applications, such as integration of surface emitting lasers, integration of small dies and 3D integration of chips with high density pin counts.