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Ground Triplate Multilayer Ceramic Structure

IP.com Disclosure Number: IPCOM000117079D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 90K

Publishing Venue

IBM

Related People

Frech, R: AUTHOR [+3]

Abstract

In Fig. 1, a dense Ground (GND) meshplane is shown. This GND mesh plane is not broken in pieces due to several reasons. One of the conditions to achieve this dense non-interrupted plane is the specific structure of the 34 chip footprint. Fig. 4 shows the chip footprint, divided in several parts. In the central area (see also Fig. 3) only PWR and GND pads are located. In the perimeter area signals and GND pads are arranged in such a way that the signal vias don't break the meshplane in pieces. In this area, however, no PWR pads (C4s) are placed. They are only located in the surrounding perimeter area. This principle can either be used in an area footprint, or in an perimeter footprint as shown in Fig. 4.

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Ground Triplate Multilayer Ceramic Structure

      In Fig. 1, a dense Ground (GND) meshplane is shown.  This GND
mesh plane is not broken in pieces due to several reasons.  One of
the conditions to achieve this dense non-interrupted plane is the
specific structure of the 34 chip footprint.  Fig. 4 shows the chip
footprint, divided in several parts.  In the central area (see also
Fig. 3) only PWR and GND pads are located.  In the perimeter area
signals and GND pads are arranged in such a way that the signal vias
don't break the meshplane in pieces.  In this area, however, no PWR
pads (C4s) are placed.  They are only located in the surrounding
perimeter area.  This principle can either be used in an area
footprint, or in an perimeter footprint as shown in Fig. 4.

      The next important structure is the Multilayer Ceramic (MLC)
cross section as shown in Fig.  3.  Only GND triplate structures are
used (GND-Rx-GND).  On top and bottom power mesh planes are located.
The center PWR & GND pads are connected through PWR/GND vias to the
meshplanes.  The perimeter PWR pads, however, are only connected to
the upper PWR mesh plane.  It has to be emphasized that this PWR
meshplane is split into center island and perimeter area.  Both parts
are only connected through the power metalization on the chip.  By
this structure it is always guaranteed that the return current path
through GND is as close as possible to the signal path.  Therefore,
the signal-GND loop in...