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Measurement of Ultrasonic Bond Quality

IP.com Disclosure Number: IPCOM000110865D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Belacicco, JA: AUTHOR [+3]

Abstract

Disclosed is a technique which employs a unique profile in discriminating between acceptable quality ultrasonic wire bonds and defective bonds. This method was found to be superior to existing methods of identifying defective wire bonds. It provides better discrimination between good bonds and defects than does current or impedance measurements, which facilitates implementing a simple tool control software algorithm for identifying defects.

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Measurement of Ultrasonic Bond Quality

      Disclosed is a technique which employs a unique profile in
discriminating between acceptable quality ultrasonic wire bonds and
defective bonds.  This method was found to be superior to existing
methods of identifying defective wire bonds.  It provides better
discrimination between good bonds and defects than does current or
impedance measurements, which facilitates implementing a simple tool
control software algorithm for identifying defects.

                  BOND VERSUS BOND/DEFECT TYPE

                 Average Mid-Point of Bond cycle

              95 Percent Confidence Interval:  N-10

      The method and apparatus has shown good separation between the
good bonds and the defective bonds.  When a sample of bonds was
considered, less overall variation existed between this method than
the method of the prior art.  In addition, it was found that the bond
transducer correlated well with bond tip vibration amplitude,
providing a practical and convenient means to measure bond quality in
process without the need for elaborate and delicate sensor equipment.

      The Figure shows a 95 percent confidence interval for good
bonds and the various defect types.  The horizontal dotted lines
depict the range in which a defect cannot be discriminated from a
good bond.  While short bonds, bonds on polyimide and bonds on
insulation can be readily culled out, cut heels and bonds o...