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"Effective" Full Dense Square Hatch Reference Planes for MLC Packaging

IP.com Disclosure Number: IPCOM000041283D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 77K

Publishing Venue

IBM

Related People

Dorler, JA: AUTHOR [+2]

Abstract

In the manufacture of multilayer ceramic (MLC) greensheets, a certain amount of greensheet dimensional instability occurs due to the interaction of the moly paste and the ceramic greensheet. As the amount of paste increases, so also does the amount of instability. In the use of a MLC card for cache memory applications a full dense square hatch reference plane (Fig. 1) is desirable. In the manufacture of a four-up configuration of each greensheet, approximately 40% more paste per greensheet is required for these reference planes. This results in considerable instability and yield loss. In order to circumvent this problem, "effective" full dense reference planes (Fig. 3) can be obtained by utilizing two distinctly designed half dense reference planes (Figs. 2A and 2B) in place of the single full dense type.

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"Effective" Full Dense Square Hatch Reference Planes for MLC Packaging

In the manufacture of multilayer ceramic (MLC) greensheets, a certain amount of greensheet dimensional instability occurs due to the interaction of the moly paste and the ceramic greensheet. As the amount of paste increases, so also does the amount of instability. In the use of a MLC card for cache memory applications a full dense square hatch reference plane (Fig. 1) is desirable. In the manufacture of a four-up configuration of each greensheet, approximately 40% more paste per greensheet is required for these reference planes. This results in considerable instability and yield loss. In order to circumvent this problem, "effective" full dense reference planes (Fig. 3) can be obtained by utilizing two distinctly designed half dense reference planes (Figs. 2A and 2B) in place of the single full dense type. Since cache or array applications require very few S,Y wiring planes, only one or two reference planes are required. Therefore, utilizing the "effective" full dense planes will increase the number of layers in these applications by only one or two layers. This penalty of additional layers is more than offset by the increased yield and allowing the reference planes to be manufactured in the four-up configuration.

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