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Browse Prior Art Database

Oxide Planarization Scheme

IP.com Disclosure Number: IPCOM000102496D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 36K

Publishing Venue

IBM

Related People

Chen, TC: AUTHOR [+2]

Abstract

Disclosed is a process for planarization of oxide filled shallow trenches, allowing a smoother and more defect-free surface to be obtained than with conventional methods.

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This is the abbreviated version, containing approximately 100% of the total text.

Oxide Planarization Scheme

       Disclosed is a process for planarization of oxide filled
shallow trenches, allowing a smoother and more defect-free surface to
be obtained than with conventional methods.

      Current art involves an etch-back of some of the excess oxide
from the shallow trench fill, followed by a chem-mech polish step to
remove the remaining excess oxide and provide a planar surface.
However, the etch-back process in general leaves "rails" or oxide
"spikes" which can break off during the chem-mech polish and cause
defects either by scratching the wafer or by causing damage where the
break occurs (Fig. 1a).  The solution described here avoids that
problem by reversing the order of the etch-back and the chem-mech
polish.  The chem-mech polish is done first, providing a relatively
planar surface, but leaving some excess oxide remaining on large
devices or dense regions.  Then, an etchback step is used to remove
the remaining excess oxide. An example of such an etch-back scheme is
shown in Fig. 1b, where advantage is taken of the fact that the
excess oxide will remain only in the center of the device area due to
the nature of the chem-mech polish.  After the final etch-back (which
can be accomplished either by a selective RIE process or by an HF
etch), a planar surface is obtained.