Browse Prior Art Database

Plane Electrical Enhancement

IP.com Disclosure Number: IPCOM000099944D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Kelleher, RJ: AUTHOR [+2]

Abstract

It is well known that electronic carriers with ground planes offer superior electrical performance compared to carriers without ground planes. This has previously been applied to Tape Automated Bonding (TAB) carriers by the addition of a ground plane which is connected to the chip mounted on the TAB carrier at the innerlead bond and to the second level carrier at the outerlead bond.

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This is the abbreviated version, containing approximately 59% of the total text.

Plane Electrical Enhancement

       It is well known that electronic carriers with ground
planes offer superior electrical performance compared to carriers
without ground planes.  This has previously been applied to Tape
Automated Bonding (TAB) carriers by the addition of a ground plane
which is connected to the chip mounted on the TAB carrier at the
innerlead bond and to the second level carrier at the outerlead bond.

      This article describes two new methods for enhancing the
electrical performance of TAB carriers.  Both methods involve the
addition of a ground plane to the carrier, but neither requires the
attachment of the plane to the chip at the innerlead bond, as has
been done in the prior art concerning TAB carriers with ground
planes.

      The following improvements will result from an application of
the methods discussed here:  reduced lead inductance, reduced coupled
noise and switching noise, and reduced radiated and received EMI.
There will be an increase in lead capacitance, but it will be no
larger than in TAB carriers with prior-art ground planes.

      In the first method, a floating (electrically isolated)
conductive area is added to the carrier in the fanout area. Although
a complete description of the electromagnetic principles governing
the behavior of this method is beyond the scope of this article, such
a conductive area allows circulating currents known as eddy currents
to flow, enhancing the electrical performance of the c...