Lithographic manufacturing process, lithographic projection apparatus, and device manufactured thereby

Abstract

A lithographic manufacturing process is disclosed in which first information of a lithographic transfer function of a first lithographic projection apparatus is obtained. The information is compared with second information of a reference lithographic transfer function (e.g. of a second lithographic projection apparatus). The difference between the first and second information is calculated. Then, the change of machine settings for the first lithographic projection apparatus, needed to minimize the difference, is calculated and applied to the first lithographic projection apparatus. In an exemplary application, a match between the first and second lithographic projection apparatus of any pitch-dependency of feature errors is improved.

1. A lithographic apparatus comprising:
 a radiation systeman illuminator configured to providemanipulate a projection beam of radiation, said radiation system illuminator having an exposure energy setting and an illumination setting; 
 a support structure configured to support hold a patterning structure, the patterning structure serves configured to pattern the projection beam according to a desired pattern; 
 a substrate table configured to hold a substrate; 
 a projection system configured to project the patterned beam onto a target portion of the substrate; 
 a memory device that provides information on spatial-frequency dependence of a lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of a referencelithographic transfer function; and 
 a processor configured to calculate (A) a difference between the information on spatial-frequency dependence of the lithographic transfer function of the lithographic apparatus spatial-frequency dependence on pitch of a feature error of a projected image by the lithographic apparatus at three or more pitches and reference information on spatial-frequency dependence of the reference lithographic transfer function at said three or more pitches on said spatial-frequency dependence on pitch, and (B) a change of at least one of said exposure energy settingand, or said illumination setting, or both said exposure energy setting and said illumination setting, to reduce said difference. 
 
     
     
       2. The lithographic apparatus according to  claim 1 , wherein the information of the lithographic transfer function of the lithographic projection apparatus on spatial-frequency dependence on pitch of a feature error includes CD-pitch anomaly. 
     
     
       3. The lithographic apparatus according to  claim 1 , wherein said patterning structure is configured to pattern the beam of radiation with the desired cross sectional pattern to obtain the patterned beam, wherein the desired cross sectional pattern comprises at least two sub-patterns, each of said at least two sub-patterns comprising features having a pitch within a respective range of pitches. 
     
     
       4. The lithographic apparatus according to  claim 3 , wherein the respective ranges of pitches are selected such that pitch<1.5 λ/NA and 0.7 λ/NA<pitch, where λ/NA denotes a principal wavelength of the projection beam directed divided by a numerical aperture of the projection system. 
     
     
       5. The lithographic apparatus according to  claim 1 , wherein the lithographic transfer function of the apparatus information on spatial-frequency dependence on pitch of a feature error is based on an observed a measured relation between critical dimension and pitch. 
     
     
       6. The lithographic apparatus according to claim  5  1, wherein the lithographic transfer function of the apparatus information on spatial-frequency dependence on pitch of a feature error includes a magnitude of lithographic errors that occur in feature error for at least two printed features of the projected image, wherein the each of the at least two printed features have has a different pitches pitch. 
     
     
       7. A lithographic apparatus comprising:
 a radiation systeman illuminator configured to providemanipulate a beam of radiation; 
 a support structure configured to support hold a patterning structure, the patterning structure serves configured to pattern the beam of radiation according to a desired pattern; 
 a substrate table configured to hold a substrate; 
 a projection system configured to project the patterned beam onto a target portion of the substrate; 
 a memory device that provides information on spatial-frequency dependence of a lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of a referencelithographic transfer function; and 
 a processor configured to calculate 
 (A) a difference between the information on spatial-frequency dependence of the lithographic transfer function of the lithographic apparatus on pitch of feature error of a projected image by the lithographic apparatus at three or more pitches and reference information on spatial-frequency dependence of the reference lithographic transfer function at said three or more pitches on said spatial-frequency dependence on pitch and 
 (B) a change of at least one machine setting of the lithographic apparatus to reduce said difference. 
 
     
     
       8. The lithographic apparatus according to  claim 7 , wherein the change of at least one machine setting includes (i) a change of exposure dose, (ii) a change of illumination setting, (iii) a change of numerical aperture of the projection system, (iv) a change of focus setting of the substrate, (v) a change of position of at least one lens element of the projection system or (vi) any combination of (i)-(v). 
     
     
       9. The lithographic apparatus according to  claim 7 , wherein said processor is configured to calculate the change of at least one machine setting based on a plurality of coefficients indicating quantitative relationships between (A) at least one difference between information of the lithographic transfer function of the lithographic apparatus and information of the reference lithographic transfer function the information on spatial-frequency dependence on pitch of a feature error and the reference information and (B) at least one machine setting of the first lithographic projection apparatus. 
     
     
       10. The lithographic apparatus according to  claim 9 , wherein said processor is configured to select the plurality of coefficients from among a larger plurality of coefficients, based on a group consisting of (i) an illumination setting of the lithographic apparatus, (ii) a setting of the projection system, (iii) a feature of the desired pattern or (iv) any combination of (i)-(iii). 
     
     
       11. The lithographic apparatus according to  claim 7 , wherein the lithographic transfer function of the apparatus information on spatial-frequency dependence on pitch of a feature error is based on a observed measured relation between critical dimension and pitch. 
     
     
       12. A lithographic apparatus comprising:
 means for providing a beam of radiation; 
 means for endowing the beam of radiation with a pattern in its cross-section; 
 means for projecting the a patterned beam of radiation onto a target portion of a layer of radiation-sensitive material; 
 means for obtaining information on spatial-frequency dependence of a lithographic transfer function of the apparatus on pitch of a feature error of a projected image by the lithographic apparatus at three or more pitches; and 
 means for calculating a change of at least one machine settings setting of the lithographic apparatus based on a relation between (A) the information on spatial-frequency dependence of the lithographic transfer function of the apparatus on pitch of a feature error and (B) reference information at said three or more pitches on spatial-frequency dependence of a reference lithographic transfer function said spatial-frequency dependence on pitch. 
 
     
     
       13. The lithographic apparatus according to  claim 12 , wherein said means for calculating the change of the at least one machine settings setting is configured to calculate the change of the at least one machine settings setting based on a difference between the information on spatial-frequency dependence of the lithographic transfer function of the apparatus on pitch of a feature error and the reference informationon spatial-frequency dependence of the reference lithographic transfer function. 
     
     
       14. The lithographic apparatus according to  claim 13 , wherein said means for calculating a the change of the at least one machine settings setting is configured to calculate the change of the at least one machine settings setting according to a minimization of the difference. 
     
     
       15. The lithographic apparatus according to  claim 12 , said apparatus further comprising means for applying the change in the at least one machine settings setting. 
     
     
       16. The lithographic apparatus according to  claim 12 , wherein the lithographic transfer function of the apparatus information on spatial-frequency dependence on pitch of a feature error is based on a observed measured relation between critical dimension and pitch. 
     
     
       17. A lithographic apparatus comprising:
 means for providing a beam of radiation, said means having an exposure energy setting and an illumination setting;   means for supporting patterning structure, the patterning structure serving to pattern the beam of radiation according to a desired pattern;   means for projecting the patterned beam onto a target portion of a substrate;   memory means for providing information on spatial-frequency dependence of a lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of a reference lithographic transfer function; and   means for calculating, based on a relation between the information on spatial-frequency dependence of lithographic transfer function of the apparatus and information on spatial-frequency dependence of the reference lithographic transfer function, a change to be applied to at least one of the exposure energy setting and the illumination setting.   
     
     
       18. The lithographic apparatus according to  claim 17 , wherein said means for calculating a change is configured to calculate the change based on a difference between information of the lithographic transfer function of the apparatus and information of the reference lithographic transfer function. 
     
     
       19. The lithographic apparatus according to  claim 18 , wherein said means for calculating a change is configured to calculate the change according to a minimization of the difference. 
     
     
       20. The lithographic apparatus according to  claim 17 , wherein the lithographic transfer function of the apparatus is based on a observed relation between critical dimension and pitch. 
     
     
       21. The lithographic apparatus according to claim 7, wherein the information on spatial-frequency dependence on pitch of a feature error includes a magnitude of feature error for at least two features of the projected image, wherein each of the at least two features has a different pitch. 
     
     
       22. The lithographic apparatus according to claim 12, wherein the information on spatial-frequency dependence on pitch of a feature error includes a magnitude of feature error for at least two features of the projected image, wherein each of the at least two features has a different pitch. 
     
     
       23. A lithographic apparatus comprising:
 an illuminator configured to manipulate a beam of radiation, said illuminator having an exposure energy setting and an illumination setting;   a support structure configured to hold a patterning structure, the patterning structure configured to pattern the beam according to a desired pattern;   a substrate table configured to hold a substrate;   a projection system configured to project the patterned beam onto a target portion of the substrate;   a memory device that provides information on spatial-frequency dependence of a lithographic, transfer function of the lithographic apparatus and information on spatial-frequency dependence of a reference lithographic transfer function; and   a processor configured to calculate (A) a difference between the information on spatial-frequency dependence of the lithographic transfer function of the lithographic apparatus and reference information on spatial-frequency dependence of the reference lithographic transfer function, and (B) a change of at least one of said exposure energy setting, or said illumination setting, or both said exposure energy setting and said illumination setting, to reduce said difference.   
     
     
       24. The lithographic apparatus according to claim 23, wherein the information of the lithographic transfer function of the lithographic projection apparatus includes CD-pitch anomaly. 
     
     
       25. The lithographic apparatus according to claim 23, wherein said patterning structure is configured to pattern the beam of radiation with the desired cross sectional pattern to obtain the patterned beam, wherein the desired cross sectional pattern comprises at least two sub-patterns, each of said at least two sub-patterns comprising features having a pitch within a respective range of pitches. 
     
     
       26. The lithographic apparatus according to claim 25, wherein the respective ranges of pitches are selected such that pitch<1.5 λ/NA and 0.7 λ/NA<pitch, where λ/NA denotes a principal wavelength of the projection beam directed by a numerical aperture of the projection system. 
     
     
       27. The lithographic apparatus according to claim 23, wherein the lithographic transfer function of the apparatus is based on a measured relation between critical dimension and pitch. 
     
     
       28. The lithographic apparatus according to claim 23, wherein the lithographic transfer function of the apparatus includes a magnitude of lithographic error that occur in two printed features, wherein the two printed features have different pitches. 
     
     
       29. A lithographic apparatus comprising:
 an illuminator configured to manipulate a beam of radiation;   a support structure configured to hold a patterning structure, the patterning structure configured to pattern the beam of radiation according to a desired pattern;   a substrate table configured to hold a substrate:   a projection system configured to project the patterned beam onto a target portion of the substrate;   a memory device that provides information on spatial-frequency dependence of a lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of a reference lithographic transfer function; and   a processor configured to calculate   (A) a difference between the information on spatial-frequency dependence of the lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of the reference lithographic transfer function, and   (B) a change of at least one machine setting of the lithographic apparatus to reduce said difference.   
     
     
       30. The lithographic apparatus according to claim 29, wherein the change of at least one machine setting includes (i) a change of exposure dose, (ii) a change of illumination setting, (iii) a change of numerical aperture of the projection system, (iv) a change of focus setting of the substrate, (v) a change of position of at least one lens element of the Projection system or (vi) any combination of (i)-(v). 
     
     
       31. The lithographic apparatus according to claim 29, wherein said processor is configured to calculate the change of at least one machine setting based on a plurality of coefficients indicating quantitative relationships between (A) at least one difference between information of the lithographic transfer function of the lithographic apparatus and information of the reference lithographic transfer function and (B) at least one machine setting of the lithographic apparatus. 
     
     
       32. The lithographic apparatus according to claim 31, wherein said processor is configured to select the plurality of coefficients from among a larger plurality of coefficients, based on a group consisting of (i) an illumination setting of the lithographic apparatus, (ii) a setting of the projection system, (iii) a feature of the desired pattern or (iv) any combination of (i)-(iii). 
     
     
       33. The lithographic apparatus according to claim 29, wherein the lithographic transfer function of the apparatus is based on a measured relation between critical dimension and pitch. 
     
     
       34. A lithographic apparatus comprising:
 means for projecting a patterned beam of radiation onto a target portion of a layer of radiation-sensitive material;   means for obtaining information on spatial-frequency dependence of a lithographic transfer function of the apparatus; and   means for calculating a change of machine settings of the lithographic apparatus based on a relation between (A) the information on spatial-frequency dependence of the lithographic transfer function of the apparatus and (B) information on spatial-frequency dependence of a reference lithographic transfer function.   
     
     
       35. The lithographic apparatus according to claim 34, wherein said means for calculating the change of machine settings is configured to calculate the change of machine settings based on a difference between the information on spatial-frequency dependence of the lithographic transfer function of the apparatus and the information on spatial-frequency dependence of the reference lithographic transfer function. 
     
     
       36. The lithographic apparatus according to claim 35, wherein said means for calculating a change of machine settings is configured to calculate the change of machine settings according to a minimization of the difference. 
     
     
       37. The lithographic apparatus according to claim 34, said apparatus further comprising means for applying the change in machine settings. 
     
     
       38. The lithographic apparatus according to claim 34, wherein the lithographic transfer function of the apparatus is based on a measured relation between critical dimension and pitch. 
     
     
       39. A lithographic apparatus comprising:
 means for manipulating a beam of radiation, said means having an exposure energy setting and an illumination setting;   means for holding a patterning structure, the patterning structure configured to pattern the beam of radiation according to a desired pattern;   means for projecting the patterned beam onto a target portion of a substrate;   memory means for providing information on spatial-frequency dependence of a lithographic transfer function of the lithographic apparatus and information on spatial-frequency dependence of a reference lithographic transfer function; and   means for calculating, based on a relation between the information on spatial-frequency dependence of lithographic transfer function of the apparatus and information on spatial-frequency dependence of the reference lithographic transfer function, a change to be applied to at least one of the exposure energy setting, or the illumination setting, or both the exposure energy setting and the illumination setting.   
     
     
       40. The lithographic apparatus according to claim 39, wherein said means for calculating a change is configured to calculate the change based on a difference between information of the lithographic transfer function of the apparatus and information of the reference lithographic transfer function. 
     
     
       41. The lithographic apparatus according to claim 40, wherein said means for calculating a change is configured to calculate the change according to a minimization of the difference. 
     
     
       42. The lithographic apparatus according to claim 39, wherein the lithographic transfer function of the apparatus is based on a measured relation between critical dimension and pitch.