Laser aids assembly of hybrid microelectromechanical devices

Hybrid microsystems must be made by combining parts produced on substrates of different materials. The relevant assembly methods normally involve manipulating individual components, which limits high-volume production. In results presented at this year's International Congress on Applications of Lasers and Electro-Optics (Oct. 2-5; Dearborn, MI), researchers from Imperial College (London, England) described a method for batch assembly of microelectromechanical devices from parts fabricated on separate substrates. The components, which are fabricated on an optically transparent carrier, are released and transferred to a target wafer by excimer-laser ablation of a polymer sacrificial layer using laser light incident through the carrier, with residual sacrificial layer material and ablation debris removed by plasma or laser-assisted cleaning. The method differs from other hybrid batch-assembly techniques because components are maintained in ordered arrays throughout the process, eliminating the need for any sorting or reordering. The process also can be applied selectively by exposing the carrier through a mask for sequential assembly. In addition, more than one type of component can be fabricated on the same carrier. Contact Andrew Holmes at[email protected].