Non-Contact Sheet Resistance Measurement of Barrier and/or Seed Layers Prior to Electroplating

Abstract

A measurement tool for measuring an electrical parameter of a metal film deposited on a front side of a workpiece includes an electrical sensor connected to a workpiece contact point, an energy beam source with a beam impact location on the front side, a holder and a translation mechanism capable of translating the holder relative to the workpiece support, the beam source supported on the holder, and a computer programmed to sense a behavior of an electrical parameter sensed by the sensor.

1 - 12 . (canceled) 
     
     
         13 . A method of measuring spatial distribution of a characteristic of a conductive film deposited on a surface of a workpiece, comprising:
 (a) selecting successive electrical return contacts at respective contact locations on said conductive film;   (b) directing an energy beam to respective beam impact locations on said conductive film, respective ones said contact locations and respective ones of said beam impact locations defining respective current paths in said conductive film; and   (c) observing respective electrical responses in said respective current paths and inferring, from said respective electrical responses, respective values of said characteristic for said respective current paths.   
     
     
         14 . The method of  claim 13  wherein said energy beam comprises a pulsed energy beam and said observing respective electrical responses is performed during respective off times of said pulsed energy beam. 
     
     
         15 . The method of  claim 13  wherein said energy beam comprises a continuous energy beam and said observing respective electrical responses comprises observing respective magnitudes of said respective electrical responses. 
     
     
         16 . The method of  claim 13  wherein successive beam impact locations are selected while a selected one of said contact locations is held constant. 
     
     
         17 . The method of  claim 13  wherein successive return contact locations are selected while a selected one of said beam impact location is held constant. 
     
     
         18 . The method of  claim 13  further comprising inferring a spatial distribution of said characteristic by correlating successive values of said characteristic with corresponding ones of said paths. 
     
     
         19 . The method of  claim 13  wherein said energy beam comprises an electron beam or a light beam. 
     
     
         20 . A method of depositing an overlying conductive layer on an underlying conductive film previously deposited on a workpiece, said method comprising:
 observing respective responses to an energy beam along respective current paths in said conductive film, inferring, from said respective responses, respective values of an electrical parameter, and deducing from said respective values a spatial distribution of said electrical parameter; and   adjusting a distribution of anode voltages among separate electroplating anodes in an electroplating solution to compensate for a non-uniformity in said spatial distribution.   
     
     
         21 . The method of  claim 13  wherein the respective contact locations are in a peripheral contact belt region of said workpiece. 
     
     
         22 . The method of  claim 21  wherein said peripheral contact belt region of said workpiece is devoid of circuit elements. 
     
     
         23 . The method of  claim 13  wherein selecting successive electrical return contacts comprises enabling different ones of a plurality of switches in successive times. 
     
     
         24 . The method of  claim 13  wherein said energy beam comprises a pulsed energy beam and observing respective electrical responses comprises determining a decay time of a current generated in said conducive film. 
     
     
         25 . The method of  claim 24  wherein inferring respective values of said characteristic comprises calculating a sheet resistance from said decay time. 
     
     
         26 . The method of  claim 13  comprising holding said respective beam impact locations constant for a plurality of different respective contact locations on said conductive film. 
     
     
         27 . The method of  claim 13  comprising selecting different respective beam impact locations for a plurality of different respective contact locations on said conductive film. 
     
     
         28 . The method of  claim 27  wherein said different respective beam impact locations are at different radial positions on said workpiece.