Browse Prior Art Database

SMT-MLC Placement Machine

IP.com Disclosure Number: IPCOM000107797D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Dahle, H: AUTHOR [+3]

Abstract

Disclosed is an improved placement machine (see the figure) which allows SMC-MLC modules to be precisely aligned to and placed into paste on FR4 cards. This machine ensures precise ball-to-card pad registration during the assembly operation.

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This is the abbreviated version, containing approximately 97% of the total text.

SMT-MLC Placement Machine

       Disclosed is an improved placement machine (see the
figure) which allows SMC-MLC modules to be precisely aligned to and
placed into paste on FR4 cards.  This machine ensures precise
ball-to-card pad registration during the assembly operation.

      An SMT-MLC module has a full array of solder terminal
connections instead of leads like conventional surface mount
components.  The outer rows of solder balls are visible, the rest of
the solder balls are hidden underneath the module and are difficult
to inspect.  Therefore, to ensure that satisfactory solder joints can
be formed, good ball-to-card pad registration is essential.

      After the ball is registered to the pad in X-Y plane,
appropriate force is applied to place SMT-MLC module into the paste
on the pad.  This machine includes two new systems:
      a)   Vision System
           This system enables a much quicker and easier alignment
operation than a microscope system.  The split prism forms dual
images of solder balls overlaid on the card pads.  The images are
shown on a monitor screen.  This allows the operator to view images
on monitor and then precisely align module to footprint on the card
by matching the two images.
      b)   Force System
           The large number of solder balls under one module make the
force setting critical.  The force is applied to the top of the
module through an air cylinder during placement and c...