A method and apparatus for creating second order vibrational modes. The apparatus includes a signal generator, a piezoelectric transducer, a plurality of wave propagating beams and reflecting boards. An electric field applied by the signal generator to the piezoelectric transducer induces a unidirectional vibration of the transducer. The vibration is propagated through the beams and reflected by the reflecting boards in a closed polygonal loop. The final reflection direction is perpendicular to the original vibration. A circular or elliptical vibration of the apparatus results. The circular or elliptical vibrational energy can be imparted to the wire bond of an integrated circuit to add strength to the connection.
An ultrasonic bonding apparatus including an ultrasonic horn formed as a horizontally symmetrical inverse triangle having two apexes besides a lower apex facing downwards; a vibrator attached to at least one apex for inputting ultrasonic vibrations in a direction facing the lower apex; and a load applying device linked to the ultrasonic horn above the lower apex and near the symmetry axis thereof, for applying a downwards pressing load. An abutting member for pressing on the objects to be bonded is provided at the lower apex of the horn. No flexing occurs at the ultrasonic horn due to the applied load, and a uniform load and ultrasonic vibrations are applied to the entire bonding face, yielding uniform and high-quality bonding.
A microelectronic assembly, and method of making the same, including a wire stitch bonded on an electroplated gold bump or electroless nickel/gold bump on a bond pad of an integrated circuit chip. The electroplated gold bump or electroless nickel/gold bump provides a relatively flat upper surface which is excellent for making a wire stitch bond thereto. The microelectronic assembly may include a multiple integrated circuit chip stack attached to a substrate such as a ball grid array. The electroplated gold bumps or electroless nickel/gold bumps may be formed on all of the integrated circuit chips and wire stitch bonds formed on the electroplated gold bumps or electroless nickel/gold bumps thereby connecting the integrated circuit chips to each other or to an underlying ball grid array.
Embodiments of a method and apparatus for imprinting a trench pattern on a substrate using ultrasonic vibrations. The trench pattern corresponds to a circuit pattern that is to be formed on the substrate, the circuit pattern including a number of conductive traces and other conductive elements. In one embodiment, the substrate includes a base layer and a layer of dielectric material overlying a surface of the base layer, and the circuit pattern is formed in the dielectric layer.
