A device for picking and placing semiconductor chips includes a liquid having a first surface and a second surface and a layer of semiconductor chips disposed over the first surface. Characteristically, the first surface is a liquid-air interface. The device also includes a focused ultrasonic transducer positioned to focus acoustic wave on the layer of semiconductor chips such that a droplet including at least one semiconductor chip is ejected through the liquid-air per each actuation of the focused ultrasonic transducer through droplet ejection. The focused ultrasonic transducer includes a piezoelectric substrate having a top face and a bottom face, a Fresnel acoustic lens including a plurality of annular rings of air cavities disposed on the top face, and a first patterned circular electrode disposed over the top face and a second patterned circular electrode disposed over the bottom face. The first patterned circular electrode overlaps the second patterned circular electrode.

Methods of and systems for assembling a plurality of ferromagnetic components into a grid-array are provided. One method includes applying a vibratory force to a magnetic stage, the magnetic stage comprising a plurality of magnets and spacers arranged in an array; depositing a plurality of ferromagnetic components, each having a ferromagnetic strip, onto the magnetic stage, the vibratory force distributing the plurality of the ferromagnetic components substantially evenly across a surface of the magnetic stage, and wherein the vibratory force aligns at least one of the plurality of ferromagnetic components with a node of maximum magnetic field strength of the magnetic stage; and removing a set of the plurality of ferromagnetic components that are not in a node of maximum magnetic field strength through physical inversion of the magnetic stage.

A device for picking and placing semiconductor chips includes a liquid having a first surface and a second surface and a layer of semiconductor chips disposed over the first surface. Characteristically, the first surface is a liquid-air interface. The device also includes a focused ultrasonic transducer positioned to focus acoustic wave on the layer of semiconductor chips such that a droplet including at least one semiconductor chip is ejected through the liquid-air per each actuation of the focused ultrasonic transducer through droplet ejection. The focused ultrasonic transducer includes a piezoelectric substrate having a top face and a bottom face, a Fresnel acoustic lens including a plurality of annular rings of air cavities disposed on the top face, and a first patterned circular electrode disposed over the top face and a second patterned circular electrode disposed over the bottom face. The first patterned circular electrode overlaps the second patterned circular electrode.