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Browse Prior Art Database

Directly Attached Decoupling Capacitors and Fabrication Process

IP.com Disclosure Number: IPCOM000037153D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Mukerjee, SP: AUTHOR [+2]

Abstract

Disclosed is a decoupling capacitor designed for direct attachment to the solder ball pads of an integrated circuit (IC) chip. Both the design and process and materials of fabrication are described.

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Directly Attached Decoupling Capacitors and Fabrication Process

Disclosed is a decoupling capacitor designed for direct attachment to the solder ball pads of an integrated circuit (IC) chip. Both the design and process and materials of fabrication are described.

The figure shows a cross-sectional view of an integrated circuit chip having solder ball connection terminals attached to a thin, flexible printed circuit carrier similar to that described in U.S. Patent 4,231,154, and having attached by solder ball terminals to the under side, a flat, thin film multi-element decoupling capacitor. The details of the geometry and connections of the capacitor are determined by the number of power voltage levels required by the IC chip and the associated solder ball connections provided.

The capacitor is made on a substrate having mechanical rigidity, electrical insulating and thermal expansion and stability properties suitable for the purpose. Silicon and certain ceramics and glasses are examples of acceptable materials. A first metallization, preferably of copper, is applied by any number of available processes, such as evaporation or sputtering, thus forming the ground or reference plate of the capacitor.

The dielectric layer is formed by one of several processes also, and a variety of materials may be selected for this layer. One possible choice is barium titanate applied by screen printing followed by sintering to remove organic binders and develop the desired high diel...