Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Presses or press platen structures – per se
Reexamination Certificate
1999-04-23
2001-02-20
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Presses or press platen structures, per se
C228S001100, C228S004500, C310S325000, C310S369000
Reexamination Certificate
active
06190497
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to ultrasonic transducers.
2. Description of Prior Art
The invention relates more particularly to such transducers for use in bonding tools for connecting semiconductors to printed circuit boards, for example. The bonding tools are used to apply pressure and ultrasonic energy simultaneously to miniature components. At present the materials used in the driver of the ultrasonic transducers are piezoelectric ceramics. The ceramic transducers have sharp resonances and high “Q”. Within the narrow bandwidth of operation, coupling of different resonance modes causes a loss of energy to unwanted modes of vibration and reduces the efficiency as well as the stability of the transducer.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome or at least reduce this problem. According to the invention there is provided a bonding tool for applying pressure and ultrasonic energy simultaneously to join miniature components together comprising an ultrasonic driver having a plurality of thin piezoelectric wafers held under mechanical pressure against each other, in which at least one of the wafers is ceramic/polymer composite having two or more ceramic parts that are separated from one another by a layer of polymer material extending in a plane parallel to a minor axis in the thickness direction of the wafer.
The ceramic/polymer composite wafer has a central longitudinal axis parallel to its minor axis and polymer material separating layers may extend in planes that are radial to the longitudinal axis. At least some of the polymer material separating layers may extend in planes transverse to the longitudinal axis.
The wafers are preferably cylindrical.
The bonding tool preferably has four ceramic/polymer composite wafers.
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patent: 5748566 (1998-05-01), Goodson
Chan Helen Lai Wa
Cheng Kei Chun
Choy Chung Loong
Or Siu Wing
Ball Michael W.
Leydig , Voit & Mayer, Ltd.
The Hong Kong Polytechnic University
Tolin Michael A
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