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Method of Producing Multilayer Boards

IP.com Disclosure Number: IPCOM000099493D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 33K

Publishing Venue

IBM

Related People

Pohl, G: AUTHOR [+2]

Abstract

The described method improves the dimensional accuracy of multilayer boards by pressure reduction during the cooling down period of the laminating press.

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This is the abbreviated version, containing approximately 96% of the total text.

Method of Producing Multilayer Boards

       The described method improves the dimensional accuracy of
multilayer boards by pressure reduction during the cooling down
period of the laminating press.

      For producing multilayer boards, several prefabricated
laminates (with conductors and power supply levels) are pressed
together, forming a circuit board.

      This is done, for example, in a hydraulic press under pressure
and at a particular temperature.  While being treated in the
hydraulic press, the dimensions of the individual circuit board
components are changed by their thermal temperature coefficient of
expansion.  As a result of the high pressure used for this purpose,
the dimensional changes of the circuit boards still exist in part
after cooling down and removal from the laminating press.

      In the subsequent manufacturing steps, during which the
components are exposed to elevated temperatures for a longer time,
this leads to adverse effects causing the circuit boards to shrink.
Such undesired dimensional changes can be considerably reduced by
tempering the circuit boards in an oven after they have left the
press.

      This additional step may be eliminated.  The lamination cycle
consists of the following steps:
    1.   heat
    2.   hold temperature
    3.   cool
    4.   hold temperature
    Instead of carrying out all 4 steps at full pressure, the
pressure in steps 3 and 4 is greatly reduced.  This perm...