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Method to Monitor and Control Ultrasonic Bond Process Quality

IP.com Disclosure Number: IPCOM000110904D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Andre, RF: AUTHOR [+5]

Abstract

A method for monitoring and controlling ultrasonic wire bonding is disclosed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 67% of the total text.

Method to Monitor and Control Ultrasonic Bond Process Quality

      A method for monitoring and controlling ultrasonic wire bonding
is disclosed.

      By monitoring the wedge tip position during bonding, the
ultrasonic process can be terminated after a desired value of
penetration (corresponding to wire deformation) has been achieved.
Automatically adjusting the duration (hence, the energy) of each bond
enhances bond quality by accommodating some of the variations in
other factors related to the bond process.

      This invention provides a method for measuring ultrasonic bond
nugget deformation by recording penetration of the bonder tip into
the wire during the bond process.  This invention also provides a
means to vary the bond process dwell time to attain the desired level
of nugget penetration.  This is achieved with a closed-loop control
system with penetration as the feedback variable (Figure).

      Nugget penetration is measured with a readily available
noncontact displacement sensor.  The sensor is attached to the
stationary part of the bond fixture.  The corresponding sensor target
is attached to the moveable part of the bond fixture onto which the
bond tool itself is mounted.  By monitoring the position of the
sensor target at the start and end times of the bond process,
penetration is measured.

      The output voltage of the displacement sensor is processed to
achieve a useable signal.  An analog low-pass filter reduces high
frequ...