Browse Prior Art Database

Surface Mount Technology Microbridge Detector

IP.com Disclosure Number: IPCOM000115503D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Darekar, VS: AUTHOR

Abstract

In the fine pitch surface mount assemblies, "microbridges" are more likely to form and hard to detect unless 100% visual inspection under high magnification is done. This disclosure describes the set up and the technique which allows an automated inspection in a short time and without a human intervention.

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Surface Mount Technology Microbridge Detector

      In the fine pitch surface mount assemblies, "microbridges" are
more likely to form and hard to detect unless 100% visual inspection
under high magnification is done.  This disclosure describes the set
up and the technique which allows an automated inspection in a short
time and without a human intervention.

      The set up comprises of an image analyzer and a simple
metallurgical microscope capable of 30X magnification.  The image
analyzer can be programmed to identify the leads with solder joint
because of their white color and a metallic lustre, according to the
shade on the well resolved gray scale.  It can count and report such
patches in the designated area bound by a geometrical shape like
square or rectangle of the size outlining the component (e.g.,
plastic quad flat pack).  When the image of such a component is
processed by image analyzer and if there is no bridging, the reported
number of white stripes will exactly match the number of leads on the
component.  If the reported number is smaller than the leads on the
component, the microbridges are present and the difference in the
numbers is the number of microbridges present.  If the reported
number is higher than the actual leads on the component, it indicates
that the solder balls are present in the spaces between the pads.
The difference in the numbers presents the number of solder balls.
The results are immediately displayed on the monitor or p...