Method and apparatus for uniform deposition onto semiconductor wafers

Abstract

A thin film on a deposition area of a wafer structure is formed of substantially parallel, substantially straight tracts of film material, adjacent ones of which partly overlap. Each tract has a lengthwise midline, and the thickness of film material and a section across each tract has a Gaussian or near-Gaussian profile with a maximum at the midline. The distance between midlines of adjacent tracts is in a range from 0.1 to 3 times a standard deviation. Also, methods for forming a thin film on a substrate, include steps of mounting the substrate on a fixture so that a surface of the substrate lies in an x-y plane, depositing onto the substrate surface a plurality of substantially parallel, substantially straight tracts of film material, each tract having a lengthwise midline, and the thickness of film material in a transverse section of each tract having a Gaussian or near-Gaussian distribution with a maximum at the midline, the distance between the midlines of adjacent partly overlapping tracts being a distance about 1.5 times a standard deviation. Also, apparatus for depositing a thin film according to the method includes a programmable controller operable to specify a deposition path and rates of relative movement of the deposition apparatus and the substrate.

1 . A method for forming a thin film on a substrate, comprising: 
 mounting the substrate on a fixture in a vacuum chamber so that a surface of the substrate lies generally within an x-y plane;    providing deposition apparatus operable within the chamber to direct a jet of film forming material along a jet axis onto a surface of the substrate, the deposition apparatus being of a type that deposits material in a Gaussian or near-Gaussian profile;    translating the substrate in an x direction relative to the deposition apparatus and operating the deposition apparatus to form a first tract of deposited material on the substrate surface, the tract being substantially straight and having a lengthwise midline defined by the locus of points of intersection of the jet axis with the x-y plane of the substrate, and the thickness of film material in a transverse section of the tract having a Gaussian or near-Gaussian distribution with a maximum at the midline;    translating the substrate in a y direction in relation to the deposition apparatus so that the jet axis passes through the x-y plane at a distance about 1.5 times a fixed standard deviation; and    translating the substrate in an x direction to form a second tract of material on the substrate surface, the second tract being substantially straight and substantially parallel to the first tract.    
     
     
         2 . The method of  claim 1  wherein the deposition apparatus includes jet vapor deposition apparatus.  
     
     
         3 . The method of  claim 1  wherein translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance from 0.1 times a standard deviation to 3 times a standard deviation.  
     
     
         4 . The method of  claim 3  wherein translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance at least about 0.5 times a standard deviation.  
     
     
         5 . The method of  claim 4  wherein translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance at least about 1 standard deviation.  
     
     
         6 . The method of  claim 3  wherein translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance no greater than about 2.5 times a standard deviation.  
     
     
         7 . The method of  claim 6  wherein translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance no greater than about 2.25 times a standard deviation.  
     
     
         8 . The method of  claim 1  wherein translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance 1.5 times a standard deviation.  
     
     
         9 . The method of  claim 1  wherein the film has a specified thickness tolerance, and translating in a y direction comprises translating the substrate so that the jet axis passes through the x-y plane at a distance related to the thickness tolerance according to the equation:  
       
         
           
             
               
                 
                   ThicknessVariation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     % 
                     ) 
                   
                 
                 = 
                 
                   14.169 
                   * 
                   
                     exp 
                     ( 
                     
                       
                         - 
                         
                           
                             ( 
                             
                               
                                 d 
                                 / 
                                 σ 
                               
                               - 
                               3.3 
                             
                             ) 
                           
                           2 
                         
                       
                       
                         2 
                         * 
                         
                           
                             ( 
                             0.58 
                             ) 
                           
                           2 
                         
                       
                     
                     ) 
                   
                 
               
               , 
               
                 
 
               
               ⁢ 
               
                 
                   when 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     d 
                     / 
                     σ 
                   
                 
                 ≤ 
                 3. 
               
             
           
         
       
     
     
         10 . A method for forming a thin film on a substrate, comprising: 
 mounting the substrate on a fixture so that a surface of the substrate lies in an x-y plane,    depositing onto the substrate surface a plurality of substantially parallel, substantially straight tracts of film material, each tract having a lengthwise midline, and the thickness of film material in a transverse section of each tract having a Gaussian or near-Gaussian distribution with a maximum at the midline, the distance between the midlines of adjacent partly overlapping tracts being a distance in a range 0.1 times a standard deviation to 3 times a standard deviation.    
     
     
         11 . The method of  claim 10  wherein the distance between the midlines of adjacent partly overlapping tracts is at least about 0.5 times a standard deviation.  
     
     
         12 . The method of  claim 11  wherein the distance between the midlines of adjacent partly overlapping tracts is at least about 1 standard deviation.  
     
     
         13 . The method of  claim 10  wherein the distance between the midlines of adjacent partly overlapping tracts is no greater than about 2.5 times a standard deviation.  
     
     
         14 . The method of  claim 13  wherein the distance between the midlines of adjacent partly overlapping tracts is no greater than about 22.5 times a standard deviation.  
     
     
         15 . The method of  claim 10  wherein the distance between the midlines of adjacent partly overlapping tracts is 1.5 times a standard deviation.  
     
     
         16 . The method of  claim 10  wherein the film has a specified thickness tolerance, and wherein the distance between the midlines of adjacent partly overlapping tracts is related to the thickness tolerance according to the equation:  
       
         
           
             
               
                 
                   ThicknessVariation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     % 
                     ) 
                   
                 
                 = 
                 
                   14.169 
                   * 
                   
                     exp 
                     ( 
                     
                       
                         - 
                         
                           
                             ( 
                             
                               
                                 d 
                                 / 
                                 σ 
                               
                               - 
                               3.3 
                             
                             ) 
                           
                           2 
                         
                       
                       
                         2 
                         * 
                         
                           
                             ( 
                             0.58 
                             ) 
                           
                           2 
                         
                       
                     
                     ) 
                   
                 
               
               , 
               
                 
 
               
               ⁢ 
               
                 
                   when 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     d 
                     / 
                     σ 
                   
                 
                 ≤ 
                 3. 
               
             
           
         
       
     
     
         17 . The method of  claim 10  wherein depositing the tracts of film material includes directing a jet of film forming material along a jet axis onto a surface of the substrate, and translating the substrate in relation to the jet in an x direction, the lengthwise midline of each tract being defined by the locus of points of intersection of the jet axis with the x-y plane of the substrate surface.  
     
     
         18 . The method of  claim 10  wherein depositing the tracts of film material includes employing deposition apparatus of a type that deposits a Gaussian profile.  
     
     
         19 . A thin film on a deposition area of a wafer structure, comprising substantially parallel, substantially straight tracts of film material, adjacent ones of which partly overlap.  
     
     
         20 . The thin film of  claim 19  wherein each tract has a lengthwise midline, and the thickness of film material in a transverse section of each tract has a Gaussian (normal) or near-Gaussian distribution with a maximum at the midline.  
     
     
         21 . The thin film of  claim 20  wherein the distance between the midlines of adjacent partly overlapping tracts is in a range 0.1 times a standard deviation to 3 times a standard deviation.  
     
     
         22 . The thin film of  claim 21  wherein the distance between the midlines of adjacent partly overlapping tracts is at least about 0.5 times a standard deviation.  
     
     
         23 . The thin film of  claim 22  wherein the distance between the midlines of adjacent partly overlapping tracts is at least about 1 times a standard deviation.  
     
     
         24 . The thin film of  claim 21  wherein the distance between the midlines of adjacent partly overlapping tracts is no greater than about 2.5 times a standard deviation.  
     
     
         25 . The thin film of  claim 24  wherein the distance between the midlines of adjacent partly overlapping tracts is no greater than about 2.25 times a standard deviation.  
     
     
         26 . The thin film of  claim 19  wherein the distance between the midlines of adjacent partly overlapping tracts is 1.5 times a standard deviation.  
     
     
         27 . The thin film of  claim 19  wherein the film has a specified thickness tolerance, and the distance between the midlines of adjacent partly overlapping tracts is related to the thickness tolerance according to the equation:  
       
         
           
             
               
                 
                   ThicknessVariation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     % 
                     ) 
                   
                 
                 = 
                 
                   14.169 
                   * 
                   
                     exp 
                     ( 
                     
                       
                         - 
                         
                           
                             ( 
                             
                               
                                 d 
                                 / 
                                 σ 
                               
                               - 
                               3.3 
                             
                             ) 
                           
                           2 
                         
                       
                       
                         2 
                         * 
                         
                           
                             ( 
                             0.58 
                             ) 
                           
                           2 
                         
                       
                     
                     ) 
                   
                 
               
               , 
               
                 
 
               
               ⁢ 
               
                 
                   when 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     d 
                     / 
                     σ 
                   
                 
                 ≤ 
                 3. 
               
             
           
         
       
     
     
         28 . The thin film of  claim 19 , comprising a material selected from the group consisting of metals, metal alloys, semiconductors, dielectric materials, organic materials, oxides, and nitrides.  
     
     
         29 . The thin film of  claim 19 , comprising a metal.  
     
     
         30 . The thin film of  claim 19 , comprising a metal alloy.  
     
     
         31 . The thin film of  claim 19 , comprising a semiconductor.  
     
     
         32 . The thin film of  claim 19 , comprising a dielectric material.  
     
     
         33 . The thin film of  claim 19 , comprising an organic material.  
     
     
         34 . The thin film of  claim 19 , comprising a nitride.  
     
     
         35 . The thin film of  claim 19 , comprising an oxide.  
     
     
         36 . The thin film of  claim 33 , the organic material comprising an OLED material.  
     
     
         37 . The thin film of  claim 33 , the organic material comprising a PLED material.  
     
     
         38 . The thin film of  claim 34 , comprising a metal nitride.  
     
     
         39 . The thin film of  claim 34 , comprising a silicon nitride.  
     
     
         40 . The thin film of  claim 35 , comprising a metal oxide.  
     
     
         41 . The thin film of  claim 35 , comprising a silicon nitride.  
     
     
         42 . A thin film as recited in  claim 19 , patterned to form integrated circuit features on a wafer.  
     
     
         43 . In integrated circuit comprising the patterned thin film of  claim 42 .  
     
     
         44 . Apparatus for forming a thin film on a surface of a substrate, comprising 
 a fixture in a chamber onto which the substrate can be mounted,    deposition apparatus operable within the chamber to direct film forming material onto the substrate in a Gaussian or near-Gaussian thickness profile,    apparatus operable to move the fixture relative to the deposition apparatus in a direction parallel to an x-y plane of the substrate surface, and    a controller operable to control the relative movement of the fixture and the deposition apparatus, the controller being programmable to direct relative movement of the deposition apparatus and the substrate in an x direction to deposit substantially straight and substantially parallel partly overlapping tracts of film material onto the substrate, each tract having a lengthwise midline and a thickness profile across the tract having a Gaussian or near-Gaussian profile, and to direct displacement of the deposition apparatus in relation to the substrate in a y direction, so that the midlines of adjacent tracts are separated by a distance in a range about 0.1 to 3 times a standard deviation.