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High Dielectric Constant On-Chip Decoupling Capacitor Incorporated into BEOL Fabrication Process

IP.com Disclosure Number: IPCOM000113918D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Beach, DB: AUTHOR [+8]

Abstract

Disclosed is an on-chip decoupling capacitor structure using a PZT dielectric sandwiched between two metal plates, which is integrated into the BEOL process, and a method of fabrication thereof. The dielectric is a pyrochlore-phase material fired at 425 deg.C in oxygen. This low firing temperature makes the capacitor fabrication process compatible with conventional BEOL processes used in chip fabrication.

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High Dielectric Constant On-Chip Decoupling Capacitor Incorporated
into BEOL Fabrication Process

      Disclosed is an on-chip decoupling capacitor structure using a
PZT dielectric sandwiched between two metal plates, which is
integrated into the BEOL process, and a method of fabrication
thereof.  The dielectric is a pyrochlore-phase material fired at
425 deg.C in oxygen.  This low firing temperature makes the capacitor
fabrication process compatible with conventional BEOL processes used
in chip fabrication.

      The capacitor is built between the upper layers of metal, which
are usually used for power distribution, and where the metal
dimensions are very wide.  This makes capacitor integration fairly
straightforward, as it takes advantage of large sheet-like metal runs
that are already there.  For a dielectric constant of 75 and a film
thickness of 1500 &angstrom., a region just 4.75 mm on a side is
needed to achieve a value of 100 nF.  No active Si are is used in
this capacitor, compared to thin gate oxide counterparts.

      The fabrication process described below produces films with a
dielectric constant of 75 and thickness of 1500 &angstrom..  The
precursor PZT solution is prepared by mixing stock solutions of lead
acetate, titanium isopropoxide, and zirconium isopropoxide in
2-methoxyethanol, followed by distillation to small volumes as
described in (*).  The mixed alkoxide solution is diluted to 0.5M
(based on Pb) with 2-methoxyethanol, hydrolyz...