Browse Prior Art Database

Planarization Process Monitor

IP.com Disclosure Number: IPCOM000099610D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Related People

Adreshak, JC: AUTHOR [+2]

Abstract

Laser via filling and metal planarization processes have been developed [*]. In these processes, a high-peak power-pulsed laser is used to briefly melt a metal layer deposited as part of an integrated circuit interconnect structure. While molten, or nearly so, the metal, owing to its high surface tension, redistributes to rapidly fill vias and form a planar surface. Accurate control of the planarizing laser fluence is essential to successful processing.

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Planarization Process Monitor

       Laser via filling and metal planarization processes have
been developed [*].  In these processes, a high-peak power-pulsed
laser is used to briefly melt a metal layer deposited as part of an
integrated circuit interconnect structure.  While molten, or nearly
so, the metal, owing to its high surface tension, redistributes to
rapidly fill vias and form a planar surface.  Accurate control of the
planarizing laser fluence is essential to successful processing.

      This article discloses a real-time technique for monitoring the
extent of planarization during a planarization process.  A low-power
probe laser beam irradiates the portion of the sample being
planarized.  The original metal film, deposited over the spatially
regular features associated with IC patterns, forms an effective
reflection grating for the probe beam.  The diffraction pattern can
be observed on a remote screen and/or digitized. Following complete
planarization, no regular array of features is available to act as a
reflection grating, and only specular reflection is observed.
Attempts to planarize films, resulting in only partial planarization,
produce only minor modifications in the diffraction pattern.
Attempts to planarize with excessive fluence, damaging the sample,
produce highly irregular probe beam reflection patterns.

      Reference (*)  D. Tuckerman and R. L. Schmitt, Proceedings of
the 1985 VLSI Multilevel Interconnection Conference (V-MI...