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Ultrasonic Chisel

IP.com Disclosure Number: IPCOM000093352D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Miller, BW: AUTHOR

Abstract

The preparation of a circuit board for mounting large-scale integrated circuits commonly includes the bonding of a large number of fine wires to copper pads on the board substrate. Since such a board represents a substantial investment when completed, it is desirable to be able to correct wiring errors on poor bonds rather than discarding the entire board. Removal of wires which are ultrasonically bonded to copper pads is accomplished without damage to the pad on the board substrate by this device. Ultrasonic transducer 1 is coupled by horn 2 to chisel head 3. To remove wire 4 bonded to copper pad 5 on board 6, head 3 is placed on pad 5 near the bond. A slight downward pressure is applied to head 3 and transducer 1 is energized. As chisel 3 is moved forward, wire 4 is sheared off.

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Ultrasonic Chisel

The preparation of a circuit board for mounting large-scale integrated circuits commonly includes the bonding of a large number of fine wires to copper pads on the board substrate. Since such a board represents a substantial investment when completed, it is desirable to be able to correct wiring errors on poor bonds rather than discarding the entire board. Removal of wires which are ultrasonically bonded to copper pads is accomplished without damage to the pad on the board substrate by this device. Ultrasonic transducer 1 is coupled by horn 2 to chisel head 3. To remove wire 4 bonded to copper pad 5 on board 6, head 3 is placed on pad 5 near the bond. A slight downward pressure is applied to head 3 and transducer 1 is energized. As chisel 3 is moved forward, wire 4 is sheared off. With proper adjustment of the downward pressure, removal of wire 4 is achieved with a loss of less than 0.0001 of an inch of pad 5 near the bond. A slight downward pressure is applied to head 3 and transducer 1 is energized. As chisel 3 is moved forward, wire 4 is sheared off. With proper adjustment of the downward pressure, removal of wire 4 is achieved with a loss of less than 0.0001 of an inch of pad 5. The surface of pad 5 is smooth so that a new wire can be bonded in exactly the same space.

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