Browse Prior Art Database

Submicron Insulation Thickness to Improve Contact Stud Density

IP.com Disclosure Number: IPCOM000101873D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Bartush, TA: AUTHOR

Abstract

This article describes a method for employing thin CVD oxide sidewalls for structural isolation in the fabrication of high density substrate device contact studs. The disclosed methodology improves product density and wireability by providing a reduction in stud edge-to-edge spacing without loss of structural integrity.

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Submicron Insulation Thickness to Improve Contact Stud Density

       This article describes a method for employing thin CVD
oxide sidewalls for structural isolation in the fabrication of high
density substrate device contact studs.  The disclosed methodology
improves product density and wireability by providing a reduction in
stud edge-to-edge spacing without loss of structural integrity.

      Current lithographic processes employed in the fabrication of
high density contact studs rely on overlay accuracy in establishing
minimum spacing requirements. Misalignment of overlay images, a
primary failure mechanism in such processes, leads to insulation
breakdown between adjacent contact studs.  The following process
steps, using proven technologies, operate together to remove such
overlay concerns while allowing for a greater density of contacts to
be achieved.  The process sequence follows:
1)   Wafers with devices ready for personalization are first coated
with photoresist and/or multilayer resist (MLR) structures for image
transfer.
2)   The emitters, or any other tightly spaced areas, are next
exposed, developed and/or etched (in MLR case) on the substrate 1, as
shown in Fig. 1.  The process should result in vertical sidewalls 2
in the resist 3, and it should cover the emitter 4 but not adjacent
base 5 and collector 6 contacts.
3)   An insulator, such as plasma nitride or plasma SiOx, is next
deposited at a few thousand angstroms thickness, e.g., 3-5000...