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Use of Easily Removable Sacrificial Layer to Suppress Chemical- Mechanical Overpolish Damage

IP.com Disclosure Number: IPCOM000121735D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Kaanta, CW: AUTHOR [+3]

Abstract

To prevent chemical-mechanical polishing (CMP) damage to an underlying insulator layer of a semiconductor structure, a readily removable sacrificial layer is utilized.

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This is the abbreviated version, containing approximately 54% of the total text.

Use of Easily Removable Sacrificial Layer to Suppress Chemical- Mechanical
Overpolish Damage

      To prevent chemical-mechanical polishing (CMP) damage to
an underlying insulator layer of a semiconductor structure, a readily
removable sacrificial layer is utilized.

      The process for the manufacture of back end of the line (BEOL)
wiring for integrated circuit chips may utilize chemical-mechanical
polishing to planarize the wiring buried within a layer of
insulation.  It is desirable to planarize the first wiring level for
the purpose of multilevel fabrication of additional wiring levels.
One process for the formation of buried wiring is the deposition of a
conductor material into recesses within the prefabricated and
planarized insulation level.  CMP is then used to remove the excess
conductor material covering the surface of the insulation layer
adjacent to the wiring recesses (overburden). Because of the
difficulties associated with uniform removal of the overburden by
CMP, there is an inherent risk with required overpolishing for
complete removal of the excess conductor material. Localized erosion
of the insulation may result.

      The use of a sacrificial layer over the insulation level will
allow for overpolishing to remove overburden without the risk of
localized erosion of the insulation level below. An additional
advantage to the use of a readily removable sacrificial layer is
avoidance of the need for a CMP etch stop.

      The process is...