Browse Prior Art Database

Characterization/Magnification of Semiconductor Device Foreign Material

IP.com Disclosure Number: IPCOM000106254D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 82K

Publishing Venue

IBM

Related People

Bouffard, MD: AUTHOR [+5]

Abstract

Described is a method which magnifies semiconductor wafer defects and foreign material (FM) particles that are significantly smaller than 0.1 micrometers in size so that they may be detected and quantified using existing inspection techniques. Defects on the semiconductor wafer surface are magnified by the conformal characteristics of many common chemical vapor deposition (CVD) films. The magnification varies with the square of the thickness of the CVD film. If the FM possesses a metallic component, the deposition rate for polysilicon low pressure CVD (LPCVD) may accelerate in the vicinity of the metal to form a spike or hornshaped growth of polysilicon. Specific metals cause unique deposition shapes that provide a means for identifying the metal.

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Characterization/Magnification of Semiconductor Device Foreign Material

      Described is a method which magnifies semiconductor wafer
defects and foreign material (FM) particles that are significantly
smaller than 0.1 micrometers in size so that they may be detected and
quantified using existing inspection techniques.  Defects on the
semiconductor wafer surface are magnified by the conformal
characteristics of many common chemical vapor deposition (CVD) films.
The magnification varies with the square of the thickness of the CVD
film.  If the FM possesses a metallic component, the deposition rate
for polysilicon low pressure CVD (LPCVD) may accelerate in the
vicinity of the metal to form a spike or hornshaped growth of
polysilicon.  Specific metals cause unique deposition shapes that
provide a means for identifying the metal.

      Examples of the appearance of some specific defects are shown
in Figs. 1 and 2.  In the cross-section shown in Fig. 1, the
conformal film has formed an approximately hemispherical shape over
the sub-micron FM particle.  The area of the hemisphere as viewed
from above is a function of the square of the film thickness.  In
Fig. 2, an FM particle has caused a horn-shaped growth that uniquely
identifies the FM as platinum.