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Fully Planarized Double Poly Self Aligned Bipolar Transistor with Self Aligned Chem Mech Polished Emitter and Collector Contact

IP.com Disclosure Number: IPCOM000109561D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 197K

Publishing Venue

IBM

Related People

Chuang, C: AUTHOR [+2]

Abstract

Disclosed is a structure/process for a high performance, double-poly self-aligned bipolar transistor with self-aligned chem-mech polished emitter and collector contact. The structure/process offers fully-planarized in-line emitter, base, and collector contacts to ease the contact/stud process and BEOL integration.

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Fully Planarized Double Poly Self Aligned Bipolar Transistor with Self Aligned Chem Mech Polished Emitter and Collector Contact

       Disclosed is a structure/process for a high performance,
double-poly self-aligned bipolar transistor with self-aligned
chem-mech polished emitter and collector contact.  The
structure/process offers fully-planarized in-line emitter, base, and
collector contacts to ease the contact/stud process and BEOL
integration.

      Double-poly self-aligned bipolar transistor has been known for
its high performance and is now an industrial standard.  However, the
severe topography of the double-poly structure has been limiting its
interfacing/integration with the BEOL processes and the extendibility
to scaled design rules.  As shown in the schematic cross-section in
Fig. 1, the topography of a double-poly self-aligned bipolar
transistor consists of the base-poly stack, the dielectric stack over
the base-poly, and the emitter-poly stack.  The severe topography has
direct impact on the emitter-poly definition process where emitter-
poly rail can form along the edges of the base-poly stack during the
emitter-poly definition process and substantial over-etch is
necessary to eliminate the rail, thus impacting directly on the
groundrules, such as the emitter-poly to emitter-opening overlay,
emitter-poly to emitter-poly spacing, and emitter-poly to base
contact spacing.  The severe topography may also cause problems in
step coverage and etch- stop in stud/contact hole etching process as
well as possible void formation in stud filling process.

      The disclosed structure/process possesses the following
features to alleviate the aforementioned problems/concerns:
(A)  Self-aligned fully-planarized chem-mech polished (CMP) emitter-
and collector-contact: After the emitter-poly deposition and
implantation of As into the emitter-poly (as in the con...