Browse Prior Art Database

New Reclaim Wafer Procedure

IP.com Disclosure Number: IPCOM000117705D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Duconge, G: AUTHOR [+5]

Abstract

Disclosed is an approach to reclaim monitor wafers with the same quality as an ingate bare silicon wafer.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 73% of the total text.

New Reclaim Wafer Procedure

      Disclosed is an approach to reclaim monitor wafers with the
same quality as an ingate bare silicon wafer.

      Presently, the sample wafer used to monitor a processing step
could not be used any longer for this processing step.  An expensive
reclaim procedure is required to allow to reuse this sample wafer.

      In any case, the reclaimed wafer could not be considered
equivalent to the initial one.  This reclaimed sample is generally
only used as a FM (FM:  Foreign Material) monitor to control
particulate contamination.

      For all the processing steps, only the first micron thick layer
is required for appropriate measurements (thickness, Rs, ionic
implant profile, MOS capacitance etc... ).  Up to now, the standard
reclaim procedure has consisted in mechanically removing 5 microns on
top of the wafer and after that to proceed to a mechanical polishing.
With this standard reclaim procedure, the monitor wafer can be twice
used before being scrapped.

      Now, according to the reclaim procedure disclosed herein, the
same sample wafer can be used at least 6 times (once as an ingate
monitor wafer and 5 times after the reclaim procedure for the same
processing step) before sending it to the polisher for a new cycle.

      After being used for a determined processing step, the monitor
wafer (P or N type) has the first micron layer thickness modified by
the process step so that it cannot be used anymore.  In e...