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The nonrobotic fabrication of packaged microsystems that contain nonidentical parts has been accomplished by a directed self-assembly process. The self-assembly process uses geometrical shape recognition to identify different components and subsequent bond formation between liquid solder and metal-coated areas to form mechanical and electrical connections. We applied this concept of shape recognition and subsequent formation of contacts to assemble and package microsystems that contained nonidentical subunits. The self-assembly of three-component assemblies is demonstrated by sequentially adding device segments to the assembly solution including 200-μm-sized light-emitting diodes. Six hundred AlGaInP-GaAs light-emitting diode segments self-assembled onto device carriers in 2 min without defects. Encapsulation units self-assembled onto the LED-carrier assemblies to form a three-dimensional (3-D) circuit path to operate the final device. The reported procedure provides a new route to the creation of autonomous heterogeneous microsystems including the realization of autonomous wireless sensor system that requires nonidentical units: CMOS circuitry, Non-CMOS sensor unit for sensing, III–V components for communication, and encapsulation units to form 3-D electrical interconnects. The creation of such systems is being discussed and a proof of concept experiment is being demonstrated. [ABSTRACT FROM AUTHOR]

This paper reports on a programmable reconfigurable self-assembly (PRS) process to enable heterogeneous integration of components on nonplanar substrates. The proposed process makes use of solder-based receptors that can be activated electrically. Metal contacts on segmented semiconductor devices bind to liquid-solder-based-receptors on a substrate during the fluidic self-assembly. Programmability is implemented using solder-based receptors that can be switched ‘ON’ and ‘OFF’ using integrated heaters. We have evaluated the feasibility of the proposed PRS concept through computer simulations using ANSYS to estimate: i) the necessary power to heat selected receptors to above the melting point of the solder and ii) the minimal spacing between receptors for preventing thermal crosstalk. A prototype platform has been fabricated to experimentally test the PRS process. The programmable sequential assembly of multiple types of components onto target positions has been demonstrated, including 300-μm-sized light-emitting diodes (LEDs) and silicon dies. Three types of defects were identified and eliminated using improved component designs, transient heating, and adequate heat sinks. A prototype color LED display segment that contains a total of 36 red, green, and yellow LED segments and 72 interconnects has been used to test the concept. The outlined process provides a new concept to the parallel integration of microdevices and systems that require electrical interconnects between components. [ABSTRACT FROM AUTHOR]

We demonstrate the fabrication of packaged microsystems that contain active semiconductor devices and passive components by using a directed self-assembly technique. The directed self-assembly is accomplished by combining geometrical shape recognition with site-specific binding involving liquid solder. Microfabricated components with matching complementary shapes, circuits, and liquid solder-coated areas were suspended in ethylene glycol and agitated by using a turbulent liquid flow to initiate the self- assembly. Microsystems were obtained by sequentially adding components of different types. Six hundred AlGalnP/GaAs light-emitting diode segments with a chip size of 200 μm were assembled onto device carriers with a yield of 100% in 2 min. Packaged light-emitting diodes formed with yields exceeding 97% as a result of two self-assembly steps in 4 min. This self-assembly procedure, based on geometrical shape recognition and subsequent binding to form mechanical and electrical connections, provides a high distinguishing power between different components and a route to nonrobotic parallel assembly of electrically functional hybrid microsystems in three dimensions. [ABSTRACT FROM AUTHOR]

The self-assembly and packaging of integrated semiconductor device segments have been accomplished by combining geometrical shape recognition with site specific wetting and binding involving liquid solder. Components with complementary shapes were fabricated to recognize and encapsulate functional semiconductor devices. The components were suspended in water and agitated using a pulsating liquid flow. Two hundred AlGaN/GaN light-emitting diodes with a chip size of 380×330 micrometers were assembled and packaged with a yield of 95% in 2 min. The self-assembly procedure forms electrical interconnects between three-dimensionally shaped objects and provides a route to parallel assembly of hybrid microsystems. [ABSTRACT FROM AUTHOR]