Metrology apparatus, lithographic apparatus, process apparatus, metrology method and device manufacturing method

Abstract

A metrology apparatus for measuring a parameter of a microscopic structure on a substrate, the apparatus comprising a supercontinuum light source arranged to generate a measurement beam, an optical system arranged to direct the measurement beam onto the substrate and a sensor for detecting radiation reflected and/or diffracted by the structure.

1 . A metrology apparatus for measuring a parameter of a microscopic structure on a substrate, the apparatus comprising a supercontinuum light source arranged to generate a measurement beam, an optical system arranged to direct the measurement beam onto the substrate and a sensor for detecting radiation reflected and/or diffracted by the structure.  
   
   
       2 . Apparatus according to  claim 1  wherein the supercontinuum light source comprises a source laser arranged to generate a first beam and a non-linear medium arranged to receive the first beam and to generate a second beam, the second beam having a greater bandwidth than the first beam.  
   
   
       3 . Apparatus according to  claim 2  wherein the source laser comprises a continuous beam laser.  
   
   
       4 . Apparatus according to  claim 2  wherein the source laser comprises a pulsed laser.  
   
   
       5 . Apparatus according to  claim 4  further comprising a positioner arranged to move the substrate relative to the sensor and a controller arranged to synchronize the supercontinuum light source to emit pulses when the substrate is in a desired position.  
   
   
       6 . Apparatus according to  claim 2  wherein the non-linear medium is selected from the group comprising doped-fibers, tapered fibers, photonic band-gap fibers and silicon-based waveguides.  
   
   
       7 . Apparatus according to  claim 1  wherein the optical system comprises an objective lens and the sensor comprises a two-dimensional sensor arranged to detect the spatial variation in intensity of radiation returned from the structure in a pupil plane of the objective lens.  
   
   
       8 . Apparatus according to  claim 7  further comprising a second optical system arranged to re-image the pupil plane of the objective lens onto the two-dimensional sensor.  
   
   
       9 . Apparatus according to  claim 7  wherein the objective lens is arranged so that the image of the structure is out of focus on the sensor.  
   
   
       10 . Apparatus according to  claim 9  wherein the objective lens is arranged so that the zeroth and at least one first order of diffracted radiation returned from the test structure overlap in the pupil plane.  
   
   
       11 . A metrology method for measuring a parameter of a microscopic structure formed on a substrate, the method comprising: 
 illuminating the structure with radiation from a supercontinuum light source; and    detecting radiation returned from the structure using a sensor.    
   
   
       12 . A method according to  claim 11  wherein said sensor is an angle-resolved scatterometer.  
   
   
       13 . A method according to  claim 12  wherein said scatterometer comprises an objective lens having a pupil plane, the objective lens being set at a defocus position such that the zeroth and at least one first order at least partially overlap in the pupil plane.  
   
   
       14 . A method according to  claim 11  wherein the structure is formed on a substrate using a lithographic process.  
   
   
       15 . A method according to  claim 14  wherein the structure is selected from the group comprising: alignment markers, CD-uniformity targets, overlay targets, diffraction gratings and device structures.  
   
   
       16 . A method according to  claim 14  wherein said structure is a latent image in a resist layer.  
   
   
       17 . A method according to  claim 11  wherein the parameter comprises position of the structure on the substrate it at least one dimension.  
   
   
       18 . A method according to  claim 11  wherein the parameter comprises overlay.  
   
   
       19 . A lithographic apparatus arranged to transfer a pattern onto a substrate and comprising a metrology device for measuring a parameter of a microscopic structure on the substrate, the apparatus comprising a supercontinuum light source arranged to generate a measurement beam, an optical system arranged to direct the measurement beam onto the substrate and a sensor for detecting radiation reflected and/or diffracted by the structure.  
   
   
       20 . A process apparatus arranged to effect a process on a substrate and comprising a metrology device for measuring a parameter of a microscopic structure on the substrate, the apparatus comprising a supercontinuum light source arranged to generate a measurement beam, an optical system arranged to direct the measurement beam onto the substrate and a sensor for detecting radiation reflected and/or diffracted by the structure.  
   
   
       21 . A device manufacturing method comprising: 
 measuring a parameter of a microscopic structure formed on a first substrate, by: 
 illuminating the structure with radiation from a supercontinuum light source; and  
 detecting radiation returned from the structure using a sensor;  
   transferring a pattern onto a second substrate using a lithographic process, a parameter of the lithographic process being determined on the basis of the measured parameter of the structure.    
   
   
       22 . A method according to  claim 21  wherein the first substrate is the second substrate.  
   
   
       23 . A method according to  claim 21  wherein the first substrate is not the second substrate.