Curvature-Based Edge Bump Quantification

Abstract

Evaluating irregularities in surfaces of objects such as semiconductor wafers using a thickness profile of a surface section and analyzing the profile to obtain information of an irregularity start position, magnitude, and span along with surface slope and height information.

1 - 36 . (canceled) 
     
     
         37 . A wafer surface profile tool for characterizing an anomaly on the wafer, comprising:
 an input for receiving sensed height information within at least a sector at an edge of the wafer,   a processor for,
 determining a shape profile for the wafer along at least a radial line within the sector, the shape profile comprising the sensed height information, 
 processing the shape profile to produce a ZDD profile, representing a radial double derivative of the sensed height information, 
 processing the ZDD profile to produce a slope profile, 
 determining an anomaly span metric from the slope profile, 
 processing the ZDD profile to produce a height profile, and 
 determining an anomaly height metric from the height profile, and an output for providing at least the anomaly span metric and the anomaly height metric. 
   
     
     
         38 . The wafer surface profile tool of  claim 37 , wherein the slope profile is produced from the ZDD profile by:
     S   b ( r )=∫ BSR   r   C (ρ) dρ 
   where   S b (r)=the slope profile,   r=radius of the wafer,   C(ρ)=the ZDD profile, and   BSR=a bump start radius.   
     
     
         39 . The wafer surface profile tool of  claim 37 , wherein the height profile is produced from the ZDD profile by:
     h   b ( r )=∫ BSR   r ∫ BSR   y   C (ρ) dρdγ 
   where   S b (r)=the slope profile,   r=radius of the wafer,   C(ρ)=the ZDD profile, and   BSR=a bump start radius.   
     
     
         40 . The wafer surface profile tool of  claim 37 , wherein the anomaly is a bump. 
     
     
         41 . The wafer surface profile tool of  claim 37 , wherein the anomaly is a recess.