Kulicke and Soffa Industries, Inc.

I Marvin Weilerstein

John D Dreibelbis

Michael Negin

Albert J Zielenski

Michael McBrearty

Apparatus is provided for monitoring conditions of a fine wire interconnection during a bonding operation. The apparatus comprise a system which is capable of being installed on new automatic wire bonders or retrofitted into existing automatic wire bonders of the type which employ a main bonding processor for controlling the motion of the bonding tool. The semiconductor to be bonded is connected to a reference voltage and a variable frequency oscillator is magnetically or a.c. coupled to the fine wire above the bonding tool and below the wire feed. The bonding wire incurs changes in inductive and capacitive reactance during the bonding operation which cause variations in the frequency of the oscillator. A series of frequency samples are taken and recorded during a teaching operation in which good wire bond interconnections are made. The recorded frequency samples for each fine wire interconnection are compared to the frequency samples being taken during subsequent bonding operations and decisions are made at critical points of the bonding operation whether or not a good wire bond interconnection is being made without damaging the semiconductor device with excessive force or current.

Wire bond monitoring system

Apparatus is provided for monitoring the bond condition of a fine aluminum wire being ultrasonically bonded to an electrode pad. The apparatus comprises a counter for generating a start and stop signal indicative of a predetermined plurality of cycles from the ultrasonic generator of the ultrasonic bonder. A stable source of pulses is applied to a second counter which is started and stopped by the start and stop signal. The count stored in the second counter is read out to a microprocessor and is indicative of the frequency of the ultrasonic generator during the bonding operation. A plurality of frequency readings are taken and measured during the formation of an ultrasonic wedge bond and this information is employed to calculate a bond quality rating which accurately predicts whether a good bond has been made or some condition exists indicating that a good bond has not been made.

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Philadelphia, PA, United States of America

I Marvin Weilerstein