Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

UV Stabilization for High Sheet Resistance Measurements

IP.com Disclosure Number: IPCOM000120020D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

LaFalce, AJ: AUTHOR

Abstract

This article concerns the use of UV (ultraviolet) radiation to stabilize high sheet resistance readings on silicon monitor wafers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 71% of the total text.

UV Stabilization for High Sheet Resistance Measurements

      This article concerns the use of UV (ultraviolet)
radiation to stabilize high sheet resistance readings on silicon
monitor wafers.

      Unstable sheet resistant (Rs) measurement from shallow (and
high resistant) implanted and annealed monitor wafers, following a
DHF (hydrofluoric acid) strip, presents a serious problem to
semiconductor manufacturing lines.  Rs measurement on silicon monitor
wafers during the first hour after DHF strip have been shown to
exceed 4% of initial measurement value, eventually increasing to more
than 6% at 24 hours.  This variation in Rs as a function of time has
been partially overcome up to now by allowing the wafers to stand for
one hour after strip before undertaking Rs measurements.

      UV treatment of the surface of the silicon monitor wafer
immediately following DHF strip has been found to be both quick and
effective in stabilizing the Rs measurement process.  The disclosed
treatment involves simply exposing the monitor wafer surfaces for a
one- minute period, including ramp up to 180oC and ramp down to room
temperature, prior to Rs measurement.  The effectiveness of this
treatment may be observed from the figure which illustrates Rs
measurements vs pre-measurement waiting time.  Two groups of wafers
are measured at 0.1 hour intervals during the first hour after being
processed through DHF strip.  Rs measurements made after waiting 24
hours are also shown b...