Device and method for characterizing a sample using localized measurements

Abstract

A device for characterizing a sample includes a measuring instrument for determining a physical characteristic of the sample, and a positioning system for positioning the measuring instrument in relation to the sample. The positioning system includes a localization target, a unit for acquiring and analysing images, and image analysis unit suitable for analysing the image of the portion of the localization target to determine the position and orientation of the optical imaging system in relation to the localization target and a processing unit processing results of image analysis and calibration, suitable for determining an absolute position of the localized measurement point in a referential system linked to the sample, the measuring instrument being positioned to take the measurement at said localized measurement point and the physical characteristic of the sample being determined by the measuring instrument at the localized measurement point.

1 . A device ( 1 ,  10 ,  110 ,  210 ) for characterizing a sample ( 11 ), the characterization device comprising:
 a measuring instrument ( 2 ,  20 ,  120 ,  220 ) adapted to determine a physical characteristic of said sample ( 11 ) at one point of said sample ( 11 ); and   a positioning system ( 3 ,  30 ,  230 ) adapted to position said measuring instrument ( 2 ,  20 ,  120 ,  220 ) in relation to said sample ( 11 ) to be characterized, at one localized measurement point of said sample ( 11 ),   wherein said positioning system ( 3 ,  30 ,  230 ) comprises:   i) a localization target ( 31 ) made integral with said sample ( 11 ) and defining a referential system linked to said sample ( 11 ), said localization target ( 31 ) comprises a plurality of elementary cells ( 310 ), each elementary cells ( 310 ) comprising at least one sub-cell formed of a draughtboard comprising white squares and black squares, each square of the draughtboard having dimensions comprised between 2 μm and 50 μm,   ii) image acquisition and analysis means including:
 means ( 321 ) for illuminating said localization target ( 31 ), 
 an optical imaging system ( 322 ), integral with said measuring instrument ( 2 ,  20 ,  120 ,  220 ), adapted to acquire an image ( 31 P) of at least one portion of said localization target ( 31 ), and 
 image analysis means ( 33 ) adapted to analyse the image ( 31 P) of said portion of the localization target ( 31 ) to determine the position and orientation of said optical imaging system ( 322 ) in relation to said localization target ( 31 ), and 
   iii) means ( 13 ) for processing the results of the image analysis, adapted to determine the absolute position of said localized measurement point in said referential system linked to said sample ( 11 ), said measuring instrument ( 2 ,  20 ,  120 ,  220 ) being positioned for the measurement at said localized measurement point and said physical characteristic of said sample ( 11 ) being determined by said measuring instrument ( 2 ,  20 ,  120 ,  220 ) at said localized measurement point.   
     
     
         2 . The characterization device ( 110 ) according to  claim 1 , including another measuring instrument ( 120 ) adapted to determine another physical characteristic of said sample ( 11 ) at one point of said sample ( 11 ), said positioning system ( 30 ) being adapted to position said other measuring instrument ( 120 ) in relation to said sample ( 11 ) at a second localized measurement point of said sample ( 11 ), said optical imaging system ( 322 ) being also integral with said other measuring instrument ( 120 ), and said result processing means ( 13 ) being adapted to determine the absolute position of said second localized measurement point in said referential system linked to said sample ( 11 ), said other physical characteristics of said sample ( 11 ) being determined by said other measuring instrument ( 120 ) at said second measurement point. 
     
     
         3 . The characterization device ( 210 ) according to  claim 1 , including another measuring instrument ( 220 ) adapted to determine another physical characteristic of said sample ( 11 ) at one point of said sample ( 11 ), said positioning system ( 230 ) being adapted to position said other measuring instrument ( 220 ) in relation to said sample ( 11 ) at a second localized measurement point of said sample ( 11 ) and comprising another optical imaging system ( 2322 ), integral with said other measuring instrument ( 220 ), adapted to acquire another image of at least one portion of said localization target ( 31 ), said image analysis means ( 233 ) being adapted to analyse said other image of the portion of said localization target ( 31 ) to determine the position and orientation of said other optical image system ( 2322 ) in relation to said localization target ( 31 ), and said result processing means ( 13 ) being adapted to determine the absolute position of said second localized measurement point in said referential system linked to said sample ( 11 ), said other physical characteristic of said sample ( 11 ) being determined by said other measuring instrument ( 220 ) at said second measurement point. 
     
     
         4 . The characterization device ( 210 ) according to  claim 1 , including another measuring instrument ( 220 ) adapted to determine another physical characteristic of said sample ( 11 ) at one point of said sample ( 11 ), said positioning system ( 230 ) being adapted to position said other measuring instrument in relation to said sample ( 11 ) at a second localized measurement point of said sample ( 11 ) and comprising:
 another optical imaging system ( 2322 ), integral with said other measuring instrument ( 220 ), adapted to acquire another image of at least one portion of said localization target ( 31 ), said image analysis means ( 233 ) being adapted to analyse said other image of the portion of the localization target ( 31 ) to determine the position and orientation of said other optical imaging system ( 2322 ) in relation to said localization target ( 31 ), and   said result processing means ( 13 ) being adapted to determine the absolute position of said second localized measurement point in said referential system linked to said sample ( 11 ), said other physical characteristic of said sample ( 11 ) being determined by said other measuring instrument ( 220 ) at said second measurement point.   
     
     
         5 . The characterization device ( 1 ,  10 ,  110 ,  210 ) according to  claim 1 , wherein said localization target ( 31 ) is engraved on or in the sample ( 11 ) through mechanical or photolithographic techniques, or is printed on the sample ( 11 ) by inking or serigraphy. 
     
     
         6 . The characterization device ( 1 ,  10 ,  110 ,  210 ) according to  claim 1 , wherein said localization target ( 31 ) comprises a flexible or rigid support added on the sample ( 11 ) to make said support integral with said sample ( 11 ). 
     
     
         7 . The characterization device ( 1 ,  10 ,  110 ,  210 ) according to  claim 1 , wherein said localization target ( 31 ) includes micro- or nanostructured patterns. 
     
     
         8 . The characterization device ( 1 ,  10 ,  110 ,  210 ) according to  claim 1 , wherein said localization target ( 31 ) is formed of said plurality of elementary cells ( 310 ) forming a regular two-dimensional pavement. 
     
     
         9 . The characterization device ( 1 ,  10 ,  110 ,  210 ) according to  claim 1 , wherein each elementary cell ( 310 ) includes:
 a positioning pattern ( 3101 A 2 ) indicating the position of said elementary cell ( 310 ) in said referential system linked to said sample ( 11 ), and   an orientation pattern ( 3101 A 1 ) indicating the orientation of said elementary cell ( 310 ) in said referential system linked to said sample ( 11 ).   
     
     
         10 . The characterization device ( 10 ,  110 ) according to  claim 1 , for a substantially planar sample ( 11 ) including a first face ( 11 A) and a second face ( 11 B), wherein:
 said measuring instrument ( 20 ,  120 ) includes an optical microscope that comprises a place intended to receive a condenser when said optical microscope is used in trans-illumination mode,   said localization target ( 31 ) is then made integral with said second face ( 11 B) of said sample ( 11 ), said localized measurement point being located on said first face ( 11 A) of said sample ( 11 ), and   said optical imaging system ( 322 ) being arranged at the place of said condenser.   
     
     
         11 . A method for characterizing a sample ( 11 ), using a measuring instrument ( 2 ,  20 ,  120 ,  220 ) adapted to determine a physical characteristic at one point of said sample ( 11 ), the method comprising the steps of:
 a) determining the relative position of said measuring instrument ( 2 ,  20 ,  120 ,  220 ) in relation to an optical imaging system ( 322 ,  2322 ), integral with said measuring instrument ( 2 ,  20 ,  120 ,  220 ),   b) placing the sample ( 11 ) to be characterized in such conditions to be measured by said measuring instrument ( 2 ,  20 ,  120 ,  220 ) at one localized measurement point of said sample ( 11 ), wherein a localization target ( 31 ) has been made integral with said sample ( 11 ), said localization target ( 31 ) defining a referential system linked to said sample ( 11 ), said localization target ( 31 ) comprising a plurality of elementary cells ( 310 ) wherein each elementary cell ( 310 ) comprises at least one sub-cell formed of a draughtboard comprising white squares and black squares, each square of the draughtboard having dimensions comprised between 2 μm and 50 μm;   c) illuminating said localization target ( 31 ) and acquiring, by means of said optical imaging system ( 322 ,  2322 ), an image ( 31 P) of at least one portion of said localization target ( 31 ), said at least one portion including said at least one sub-cell formed of a draughtboard,   d) determining, from the analysis of the image ( 31 P) of said portion of the localization target ( 31 ), the position and orientation of said optical imaging system ( 322 ,  2322 ) in relation to said localization target ( 31 ), and   e) deducing from steps a) and d) the absolute position of said localized measurement point in said referential system linked to said sample ( 11 ), when said measuring instrument ( 2 ,  20 ,  120 ,  220 ) is positioned for the measurement at said localized measurement point, so as to determine said physical characteristic of said sample ( 11 ) by said measuring instrument ( 2 ,  20 ,  120 ,  220 ) at said localized measurement point.   
     
     
         12 . The characterization device according to  claim 1 , wherein each elementary cell of said plurality of elementary cells includes two non-adjacent distinct sub-cells formed of a draughtboard comprising white squares and black squares, each square of said draughtboard of having dimensions comprised between 2 μm and 50 μm. 
     
     
         13 . The characterization device according to  claim 9 , wherein each elementary cell of said plurality of elementary cells includes another distinct sub-cell including said positioning pattern and said orientation pattern. 
     
     
         14 . The characterization device according to  claim 1 , wherein each elementary cell of said plurality of elementary cells includes an identification pattern coding information relating to said sample and/or said localization target. 
     
     
         15 . The characterization device according to  claim 14 , wherein said identification pattern is identical for each elementary cell of said plurality of elementary cells. 
     
     
         16 . The characterization device according to  claim 12 , wherein each elementary cell of said plurality of elementary cells includes at least three distinct sub-cells, two non-adjacent distinct sub-cells of said at least three distinct sub-cells being formed of a draughtboard comprising white squares and black squares, each square of said draughtboard of having dimensions comprised between 2 μm and 50 μm, another distinct sub-cell of said at least three distinct sub-cells including said positioning pattern and said orientation pattern. 
     
     
         17 . The characterization device according to  claim 12 , wherein each elementary cell of said plurality of elementary cells includes at least three distinct sub-cells, two non-adjacent distinct sub-cells of said at least three distinct sub-cells being formed of a draughtboard comprising white squares and black squares, each square of said draughtboard of having dimensions comprised between 2 μm and 50 μm, and still another distinct sub-cell of said at least three distinct sub-cells including said identification pattern. 
     
     
         18 . The characterization device according to  claim 13 , wherein each elementary cell of said plurality of elementary cells includes at least three distinct sub-cells, a distinct sub-cell of said at least three distinct sub-cells being formed of a draughtboard comprising white squares and black squares, each square of said draughtboard of having dimensions comprised between 2 μm and 50 μm, another distinct sub-cell of said at least three distinct sub-cells including said positioning pattern and said orientation pattern and still another distinct sub-cell of said at least three distinct sub-cells including said identification pattern. 
     
     
         19 . The characterization device according to  claim 12 , wherein each elementary cell of said plurality of elementary cells includes four distinct sub-cells, two non-adjacent distinct sub-cells of said four distinct sub-cells being formed of a draughtboard comprising white squares and black squares, each square of said draughtboard of having dimensions comprised between 2 μm and 50 μm, another distinct sub-cell of said four distinct sub-cells including said positioning pattern and said orientation pattern and still another distinct sub-cell of said four distinct sub-cells including said identification pattern. 
     
     
         20 . The characterization device according to  claim 13 , wherein each elementary cell of said plurality of elementary cells includes at least three distinct sub-cells, two non-adjacent distinct sub-cells of said at least three distinct sub-cells being formed of a draughtboard comprising white squares and black squares, each square of said draughtboard of having dimensions comprised between 2 μm and 50 μm, another distinct sub-cell of said at least three distinct sub-cells including said positioning pattern and said orientation pattern.