Periodic patterns and technique to control misalignment

Abstract

A method and system to measure misalignment error between two overlying or interlaced periodic structures are proposed. The overlying, or interlaced periodic structures are illuminated by incident radiation, and the diffracted radiation of the incident radiation by the overlying or interlaced periodic structures are detected to provide an output signal. The misalignment between the overlying or interlaced periodic structures may then be determined from the output signal.

1 - 20 . (canceled)  
   
   
       21 . A method for detecting misalignment of overlying or interlaced periodic structures, comprising: 
 illuminating the overlying or interlaced periodic structures with incident radiation;    detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures to provide an output signal; and    determining a misalignment between the structures from the output signal.    
   
   
       22 . The method of  claim 21 , wherein said determining includes comparing the output signal with a reference signal.  
   
   
       23 . The method of  claim 22 , wherein the reference signal comprises a database.  
   
   
       24 . The method of  claim 21 , wherein the output signal contains information related to ellipsometric parameters.  
   
   
       25 . The method of  claim 21 , wherein said overlying or interlaced periodic structures comprise at least two interlaced grating lines having different periods, line widths or duty cycles; the incident radiation is incident on the structures at an oblique angle; and the diffracted radiation comprises zero-order diffraction.  
   
   
       26 . The method of  claim 21 , wherein said overlying or interlaced periodic structures comprise at least two interlaced grating lines having different periods, line widths or duty cycles; the incident radiation is incident on the structures at a normal angle; and the diffracted radiation comprises zero-order diffraction.  
   
   
       27 . The method of  claim 21 , wherein the incident radiation is substantially normal, and the diffracted radiation comprises positive first-order diffraction and negative first-order diffraction.  
   
   
       28 . The method of  claim 21 , further comprising calculating a derived signal from the output signal.  
   
   
       29 . The method of  claim 28 , wherein the derived signal contains information related to intensity, phase, or polarization angle.  
   
   
       30 . The method of  claim 28 , wherein the derived signal contains information related to differential intensity, differential phase, or differential polarization angle.  
   
   
       31 . The method of  claim 28 , further comprising providing a neutral polarization angle or quasi-neutral polarization angle; and wherein said determining a misalignment includes determining a misalignment by comparing the derived signal with the reference signal near the neutral polarization angle or the quasi-neutral polarization angle.  
   
   
       32 . The method of  claim 31 , wherein the derived signal is compared with the reference signal for polarization angles of said incident radiation within about five degrees of a neutral polarization angle or a quasi-neutral polarization angle.  
   
   
       33 . An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising: 
 a source providing polarized incident radiation beam to illuminate the overlying or interlaced periodic structures;    at least one analyzer collecting diffracted radiation from the structures;    at least one detector detecting diffracted radiation collected by the analyzer to provide output signals; and    a signal processor determining any misalignment between the structures from the output signals.    
   
   
       34 . The apparatus of  claim 33 , wherein the source provides said incident radiation beam at an oblique angle of incidence to illuminate the overlying or interlaced periodic structures, and the detector detects zero-order diffraction.  
   
   
       35 . The apparatus of  claim 33 , wherein the source provides a normal incident radiation beam to illuminate the overlying or interlaced periodic structures, and the detector detects zero-order diffraction.  
   
   
       36 . The apparatus of  claim 33 , wherein the source includes a polarizer and a device causing relative rotational motion between the polarizer and the analyzer.  
   
   
       37 . The apparatus of  claim 33 , wherein said at least one analyzer comprises a first analyzer collecting positive first-order diffracted radiation and a second analyzer collecting negative first-order diffracted radiation; and said at least one detector comprises a first detector detecting positive first-order diffracted radiation, and a second detector detecting negative first-order diffracted radiation.  
   
   
       38 . The apparatus of  claim 37 , wherein the signal processor calculates a derived signal from the output signals.  
   
   
       39 . The apparatus of  claim 38 , wherein the derived signal contains information related to a differential intensity, a differential phase, or a differential polarization angle.  
   
   
       40 . The apparatus of  claim 38 , wherein the source includes a polarizer, said apparatus further comprising a device causing relative rotational motion between the polarizer and the analyzers.  
   
   
       41 . The apparatus of  claim 40 , wherein the derived signal contains information related to a differential polarization angle or a phase difference derived from ellipsometric parameters.  
   
   
       42 - 43 . (canceled)  
   
   
       44 . An apparatus for making overlying or interlaced periodic structures and detecting misalignment between the overlying or interlaced periodic structures, comprising: 
 a deposition instrument to provide the overlying or interlaced periodic structures;    a source providing polarized incident radiation beam to illuminate the overlying or interlaced periodic structures;    at least one analyzer collecting diffracted radiation from the structures;    at least one detector detecting diffracted radiation collected by the analyzer to provide output signals; and    a signal processor determining any misalignment between the structures from the output signals and providing the misalignment to the deposition instrument.    
   
   
       45 . The apparatus of  claim 44 , wherein the source provides the incident radiation beam at an oblique angle of incidence to illuminate the overlying or interlaced periodic structures, and the detector detects zero-order diffraction.  
   
   
       46 . The apparatus of  claim 44 , wherein the source provides a normal incident radiation beam to illuminate the overlying or interlaced periodic structures, and the detector detects zero-order diffraction.  
   
   
       47 . The apparatus of  claim 44 , wherein the source includes a polarizer and a device causing relative rotational motion between the polarizer and the analyzer.  
   
   
       48 . The apparatus of  claim 44 , wherein said at least one analyzer comprises a first analyzer collecting positive first-order diffracted radiation and a second analyzer collecting negative first-order diffracted radiation; and said at least one detector comprises a first detector detecting positive first-order diffracted radiation, and a second detector detecting negative first-order diffracted radiation.  
   
   
       49 . The apparatus of  claim 48 , wherein the signal processor calculates a derived signal from the output signals.  
   
   
       50 . The apparatus of  claim 49 , wherein the derived signal contains information related to a differential intensity, a differential phase, or a differential polarization angle.  
   
   
       51 . The apparatus of  claim 49 , wherein the source includes a polarizer, said apparatus further comprising a device causing relative rotational motion between the polarizer and the analyzers.  
   
   
       52 . The apparatus of  claim 51 , wherein the derived signal contains information related to a differential polarization angle or a phase difference derived from ellipsometric parameters.  
   
   
       53 - 54 . (canceled)  
   
   
       55 . A method for controlling layers alignment in a multi-layer sample, the method comprising the steps of: 
 (i) providing a measurement site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures of certain known periodicity;    (ii) illuminating said site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures; and    (iii) analyzing said parameter to determine an existing lateral shift between the layers.    
   
   
       56 . The method of  claim 55 , said pattern structures characterized by substantially the same periodicity.  
   
   
       57 . The method of  claim 56 , further comprising the steps of providing at least one additional site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures; illuminating said additional site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures and analyzing the parameters obtained in said sites to determine an existing lateral shift between the layers.  
   
   
       58 . The method of  claim 57  wherein at least one of additional sites comprises pattern structures at essentially right angle to the pattern structures of the measurement site.  
   
   
       59 . The method of  claim 55 , further comprising the step of providing additional sites including regions containing pattern structures in one of the layers.  
   
   
       60 . The method of  claim 55  wherein said detecting the parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures comprises measuring said parameter as a function of wavelength.  
   
   
       61 . The method of  claim 55  wherein said detecting the parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures comprises measuring radiation from the patterned structures at different angles.  
   
   
       62 . The method of  claim 61 , wherein said measuring measures radiation diffracted from the patterned structures at different angles.  
   
   
       63 . The method of  claim 61 , wherein said illuminating directs radiation to the site in a direction substantially normal to the regions.  
   
   
       64 . The method of  claim 55  wherein said detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures comprises measuring said parameter as a function of a variable related to change of polarization amplitude and/or phase of the diffracted light.  
   
   
       65 . The method of  claim 55  wherein the step of illuminating said site with electromagnetic radiation comprises illuminating with polarized light with different states of polarization.  
   
   
       66 . The method of  claim 55  wherein said patterned structures are two- dimensional.  
   
   
       67 . The method of  claim 66 , the step of illuminating said site with electromagnetic radiation comprising illuminating with polarized light with different states of polarization.  
   
   
       68 . The method of  claim 55 , wherein said multi-layer sample comprises a semiconductors wafer.  
   
   
       69 . The method of  claim 55 , further comprising the steps of providing at least one additional reference site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures; illuminating said additional reference site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures and analyzing the parameters obtained in said sites to determine an existing lateral shift between the layers of said multi-layer sample.  
   
   
       70 . The method of  claim 69 , wherein said at least one additional reference site is on a second sample different from the multi-layer sample, and the steps of illuminating said additional reference site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures are performed on said second sample.  
   
   
       71 . The method of  claim 55 , wherein the analyzing analyzes the parameter obtained in said site in association with a database to determine an existing lateral shift between the layers of said multi-layer sample.  
   
   
       72 . The method of  claim 71 , further comprising providing information related to one or more of thickness, refractive index, extinction coefficient and critical dimension and constructing said database from such information.  
   
   
       73 . The method of  claim 55 , wherein said illuminating directs radiation to the site in a direction substantially normal to the regions.  
   
   
       74 . An apparatus for controlling alignment of layers in a multi-layer sample, comprising: 
 a measurement site including two regions located one above the other in two different layers of the sample, respectively, said regions containing patterned structures of certain known periodicity;    optics illuminating said site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures; and    a processor analyzing said parameter to determine an existing lateral shift between the layers.    
   
   
       75 . The apparatus of  claim 74 , said pattern structures characterized by substantially the same periodicity.  
   
   
       76 . The apparatus of  claim 75 , further comprising at least one additional site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures; said optics illuminating said additional site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures and processor analyzing the parameters obtained in said sites to determine an existing lateral shift between the layers.  
   
   
       77 . The apparatus of  claim 74 , wherein said optics measures said parameter as a function of wavelength.  
   
   
       78 . The apparatus of  claim 74  wherein said optics measures said parameter as a function of a variable related to change of polarization amplitude and/or phase of the diffracted light.  
   
   
       79 . The apparatus of  claim 74  wherein at least one of additional sites comprises pattern structures at essentially right angle to the pattern structures of the measurement site.  
   
   
       80 . The apparatus of  claim 74  wherein the optics illuminates the site with polarized light with different states of polarization.  
   
   
       81 . The apparatus of  claim 74  wherein said patterned structures are two- dimensional.  
   
   
       82 . The apparatus of  claim 74  wherein said multi-layer sample comprises a semiconductors wafer.  
   
   
       83 . The apparatus of  claim 74  wherein said two regions of the measurement site are connected to a common substrate.  
   
   
       84 . A method for controlling layers alignment in a multi-layer sample, the method comprising: 
 (i) providing a measurement site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures of certain known periodicity;    (ii) illuminating said site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures; and    (iii) analyzing said parameter to determine an existing lateral shift between the layers.    
   
   
       85 . A method for measuring layers alignment in a multi-layer sample, the method comprising the steps of: 
 (i) providing a measurement site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures of certain known periodicity;    (ii) illuminating said site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures; and    (iii) analyzing said parameter to determine an existing lateral shift between the layers.    
   
   
       86 . An apparatus for measuring alignment of layers in a multi-layer sample, comprising: 
 a measurement site including two regions located one above the other in two different layers of the sample, respectively, said regions containing patterned structures of certain known periodicity;    optics illuminating said site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures; and    a processor analyzing said parameter to determine an existing lateral shift between the layers.    
   
   
       87 . A method for measuring layers alignment in a multi-layer sample, the method comprising: 
 (i) providing a measurement site including two regions located one above the other in two different layers, respectively, said regions containing patterned structures of certain known periodicity;    (ii) illuminating said site with electromagnetic radiation and detecting a parameter of radiation diffracted from the patterned structures indicative of a lateral shift between the patterned structures; and    (iii) analyzing said parameter to determine an existing lateral shift between the layers.    
   
   
       88 . A line-on-line structure, comprising: 
 a first layer having a plurality of lines of a first medium and a plurality of lines of a second medium, each line of the first medium being placed adjacent to lines of the second medium; and    a second layer having a plurality of lines of a third medium and a plurality of lines of the second medium, each line of the third medium being aligned with a center of a line of the first medium in the first layer, each of said first and third media having an optical property different from that of the second medium.    
   
   
       89 . The line-on-line structure of  claim 88 , wherein the plurality of lines of the second medium in the first layer are identical or substantially identical to one another, and wherein the plurality of the lines of the first medium in the first layer are identical or substantially identical to one another, thereby the combination of the lines of the first and second media in the first layer producing a repetitive pattern.  
   
   
       90 . The line-on-line structure of  claim 88 , the plurality of lines of the first medium in the first layer being wider than the plurality of lines of the third medium in the second layer.  
   
   
       91 . The line-on-line structure of  claim 88 , the plurality of lines of the second medium in the first layer being narrower than the plurality of lines of the second medium in the second layer.  
   
   
       92 . The line-on-line structure of  claim 88 , one of the lines of the third medium in the second layer having a left edge and a right edge, and one of the lines of the first medium in the first layer having a left edge and a right edge.  
   
   
       93 . The line-on-line structure of  claim 92 , further comprising a distance d1 measuring a gap from the left edge of said one of the lines of the third medium in the second layer to the left edge of said one of the lines of the first medium in the first layer; and a distance d2 measuring a gap from the right edge of said one of the lines of the third medium in the second layer to the right edge of said one of the lines of the first medium in the first layer.  
   
   
       94 . The line-on-line structure of  claim 93 , wherein said one of the lines of the third medium in the second layer is aligned with a center of said one of the lines of the first medium in the first layer if d1=d2.  
   
   
       95 . The line-on-line structure of  claim 93 , wherein said one of the lines of the third medium in the second layer is shifted to the right of said one of the lines of the first medium in the first layer if d1 minus d2 produces a positive number.  
   
   
       96 . The line-on-line structure of  claim 93 , wherein said one of the lines of the third medium in the second layer is shifted to the left of said one of the lines of the first medium in the first layer if d1 minus d2 produces a negative number.  
   
   
       97 . The line-on-line structure of  claim 88 , wherein the first and second layers are connected to one another or through at least another layer to form an integral structure.  
   
   
       98 . A line-in-line structure, comprising: 
 a first layer having a plurality of lines of a first medium and a plurality of lines of a second medium, each line of the first medium being placed adjacent to lines of the second medium; and    a second layer having a plurality of lines of a third medium and a plurality of lines of the second medium, each line of the second medium in the second layer being aligned with a center of a line of the second medium in the first layer, each of said first and third media having an optical property different from that of the second medium.    
   
   
       99 . The line-in-line structure of  claim 98 , the plurality of lines of the second medium in the first layer being narrower than the plurality of lines of the second medium in the second layer.  
   
   
       100 . The line-in-line structure of  claim 98 , wherein the plurality of lines of the second medium in the first layer are identical or substantially identical to one another, and wherein the plurality of the lines of the first medium in the first layer are identical or substantially identical to one another, thereby the combination of the lines of the first and second media in the first layer producing a repetitive pattern.  
   
   
       101 . The line-in-line structure of  claim 98 , the plurality of lines of the first medium in the first layer being narrower than the plurality of lines of the third medium in second layer.  
   
   
       102 . The line-in-line structure of  claim 98 , wherein the plurality of lines of the second medium in the first layer being wider than the plurality of lines of the second medium in the second layer.  
   
   
       103 . The line-in-line structure of  claim 98 , one of the lines of the second medium in the second layer having a left edge and a right edge, and wherein one of the lines of the second medium in the first layer having a left edge and a right edge.  
   
   
       104 . The line-in-line structure of  claim 103 , further comprising: 
 a first distance from the left edge of said one of the lines of the second medium in the second layer to the left edge of one of the lines of the second medium in the first layer; and    a second distance from the right edge of said one of the lines of the second medium in the second layer to the right edge of said one of the lines of the second medium in the first layer.    
   
   
       105 . The line-in-line structure of  claim 104 , wherein said one of the lines of the second medium in the second layer is aligned with a center of said one of the lines of the second medium in the first layer if the first and second distances are equal.  
   
   
       106 . The line-in-line structure of  claim 104 , wherein said one of the lines of the second medium in the second layer is shifted to the right of said one of the lines of the second medium in the first layer if the first distance minus the second distance produces a positive number.  
   
   
       107 . The line-in-line structure of  claim 104 , wherein said one of the lines of the second medium in the second layer is shifted to the left of said one of the lines of the second medium in the first layer if the first distance minus the second distance produces a negative number.  
   
   
       108 . A method for multi-orientation of orthogonal pairs, comprising: 
 placing a grating; and    shining light on the grating wherein the light is not perpendicular to the orientation of the grating.    
   
   
       109 . A line-in-line structure, comprising: 
 a first layer having a plurality of lines of a first medium and a plurality of lines of a second medium, each line of the first medium being placed adjacent to lines of the second medium; and    a second layer having a plurality of lines of a third medium and a plurality of lines of a fourth medium, each line of the fourth medium in the second layer being aligned with a center of a line of the second medium in the first layer, each of said first and third media having an optical property different from that of the second and/or fourth media.    
   
   
       110 . The line-in-line structure of  claim 109 , the plurality of lines of the second medium in the first layer being narrower than the plurality of lines of the fourth medium in the second layer.  
   
   
       111 . The line-in-line structure of  claim 109 , wherein the plurality of lines of the second medium in the first layer are identical or substantially identical to one another, and wherein the plurality of the lines of the first medium in the first layer are identical or substantially identical to one another, thereby the combination of the lines of the first and second media in the first layer producing a repetitive pattern.  
   
   
       112 . The line-in-line structure of  claim 109 , the plurality of lines of the first medium in the first layer being narrower than the plurality of lines of the third medium in second layer.  
   
   
       113 . The line-in-line structure of  claim 109 , wherein the plurality of lines of the second medium in the first layer being wider than the plurality of lines of the fourth medium in the second layer.  
   
   
       114 . The line-in-line structure of  claim 109 , one of the lines of the fourth medium in the second layer having a left edge and a right edge, and wherein one of the lines of the second medium in first layer having a left edge and a right edge.  
   
   
       115 . The line-in-line structure of  claim 114 , further comprising: 
 a first distance from the left edge of said one of the lines of the fourth medium in the second layer to the left edge of one of the lines of the second medium in the first layer; and    a second distance from the right edge of said one of the lines of the fourth medium in the second layer to the right edge of said one of the lines of the second medium in the first layer.    
   
   
       116 . The line-in-line structure of  claim 115 , wherein said one of the lines of the fourth medium in the second layer is aligned with a center of said one of the lines of the second medium in the first layer if the first and second distances are equal.  
   
   
       117 . The line-in-line structure of  claim 115 , wherein said one of the lines of the fourth medium in the second layer is shifted to the right of said one of the lines of the second medium in the first layer if the first distance minus the second distance produces a positive number.  
   
   
       118 . The line-in-line structure of  claim 115 , wherein said one of the lines of the fourth medium in the second layer is shifted to the left of said one of the lines of the second medium in the first layer if the first distance minus the second distance produces a negative number.