Lithography system, sensor and measuring method

Abstract

Lithography system, sensor and method for measuring properties of a massive amount of charged particle beams of a charged particle beam system, in particular a direct write lithography system, in which the charged particle beams are converted into light beams by using a converter element, using an array of light sensitive detectors such as diodes, CCD or CMOS devices, located in line with said converter element, for detecting said light beams, electronically reading out resulting signals from said detectors after exposure thereof by said light beams, utilizing said signals for determining values for one or more beam properties, thereby using an automated electronic calculator, and electronically adapting the charged particle system so as to correct for out of specification range values for all or a number of said charged particle beams, each for one or more properties, based on said calculated property values.

The invention claimed is: 
     
       1. A method of measuring properties of a massive amount of charged particle beams of a charged particle beam system in which
 the charged particle beams are simultaneously converted into light beams by using a converter element,   using an array of light sensitive detectors such as diodes, CCD or CMOS devices, located in line with said converter element, for detecting said light beams,   electronically reading out resulting signals for each beam individually from said detectors after exposure thereof by said light beams,   utilizing said individual signals for determining values for one or more beam properties, thereby using an automated electronic calculator, and   electronically adapting the charged particle system so as to correct for out of specification range values for all or a number of said charged particle beams individually, for one or more properties, based on said calculated property values,   wherein determination of beam position and/or beam spot size is performed on the basis of signals resulting from a converted charged particle beam ( 4 ), thereby using a blocking element, configured to selectively partially and entirely block a beam, included at a known position relative to the converter   while shifting the blocking element and the charged particle beam relative to each another by one or more known shifts,   wherein the charged particle blocking element ( 6 ) is applied integrated with said converter element, located on top thereof, and wherein said detector element is applied integrated with said converter element, located on bottom thereof.   
     
     
       2. Method according to  claim 1 , wherein adaptation of the system is performed by at least one of
 electronically modifying electronic data for a pattern to be imaged by said charged particle beam system,   modifying line width, and   electronically influencing a position modifying means of said beam system, for modifying the position of one or more charged particle beams.   
     
     
       3. Method according to  claim 2 , in which the system is adapted solely by modifying said electronic data. 
     
     
       4. Method according to  claim 1 , in which the spot size of said charged particle beams is smaller than the resolution of the converter element. 
     
     
       5. Method according to  claim 4 , in which the intensity of a light beam is utilised for determining a beam property value. 
     
     
       6. Method according to  claim 5 , in which a knife-edge is used in combination with said light intensity for deriving a value for a spot size in one direction. 
     
     
       7. Method according to  claim 6 , in which values for spot size in at least two directions is used for deriving a spot shape. 
     
     
       8. Method according to  claim 1 , wherein determination of beam properties is performed on the basis of a plurality of signals resulting from a stepping proceed of a charged particle beam being scanned in one direction at a time over said blocking element. 
     
     
       9. Method according to the  claim 1 , in which a beam is switched off and on during such scan. 
     
     
       10. Method according to  claim 1 , wherein a switching “off” and “on” is incrementally delayed during multiple scans in one direction, relative to the starting point of the scan. 
     
     
       11. Method according to  claim 1 , wherein pulse duration variation is determined using a measurement with predetermined beam on/off timing. 
     
     
       12. Method according to  claim 1 , wherein the light beam resulting from impingement of a charged particle beam on said converter is optically modified for receipt by said light sensitive detector, in particular by means of a lens system, more in particular such that said resulting light beams are kept apart from one another, i.e. are modified such that no overlap between said resulting beams occurs. 
     
     
       13. Method according to  claim 1 , wherein a number of beam properties is derived using a beam detector comprising a beam blocking element, a converter element an electronically readable photon receptor element, an actuator for realising a relative movement of an electron beam and a beam blocker, and an electronic calculating unit (Cu), said properties at least including one or more of beam position, timing delay of a possible blanker device acting upon said particle beam, beam spot size, beam current and blanking element functioning. 
     
     
       14. The method according to  claim 1 , wherein the charged particle beam system, at least the beam generating part thereof is provided with an optical sensor, and wherein the detector for detecting beam properties is utilised for optically detecting the position of said system relative to an independently moveable stage for holding a target surface and comprising said detector. 
     
     
       15. The method according to  claim 1  for measuring properties of a massive amount of charged particle beams of a direct write lithography system. 
     
     
       16. A sensor embodied for performing the measuring method in accordance with  claim 1 . 
     
     
       17. A sensor for simultaneously measuring one or more of a beam position and a beam spot size of one or more individual particle beams in a lithography system characterized in that the sensor comprises a converter for converting a particle beam into a light beam, as well as a photon receptor arranged for receiving a light beam emitted by said converter upon incidence of a particle beam, and transforming light from said received light beam into an electronic signal, enabling read out of said signal from the sensor by an electronic control system, in which a beam blocking element, configured to selectively partially and entirely block a beam is provided to the surface of said converter, and in which the blocking element is integrated with said converter and located on top thereof and wherein said detector element is applied integrated with said converter element, located on bottom thereof. 
     
     
       18. The sensor according to  claim 17 , characterised in that for each beamlet a separate blocking element is provided. 
     
     
       19. The sensor according to  claim 17 , in which the blocking element is provided with a sharp edge as taken perpendicularly to the surface of the converter means. 
     
     
       20. The sensor according to  claim 17 , wherein the blocking element is provided with a number of sharp edges. 
     
     
       21. The sensor according  claim 17 , in which the blocking element is composed of a heavy material, of a thickness within a range from 50 to 500 nm. 
     
     
       22. The sensor according to  claim 17 , wherein the sensor includes a thin layer of light metal, between said blocking element and said converter of a thickness within the range from 30 to 80 nm. 
     
     
       23. The sensor according to  claim 17 , wherein the sensor includes at least one blocking element having three sharp edges mutually included in a hexagon shape. 
     
     
       24. The sensor according to  claim 17 , in which an optical system is included between the converter element and the light sensitive detector. 
     
     
       25. The sensor according to  claim 17  for measuring properties of a massive amount of charged particle beams of a direct write lithography system. 
     
     
       26. A lithography system for transferring a pattern onto the surface of a target, using a charged particle beam tool, said tool being capable of generating a plurality of charged particle beams for writing said pattern on said surface, in which either one of the measuring method according to  claim 1  and the sensor in accordance with  claim 17  is applied. 
     
     
       27. A lithography system for transferring a pattern onto the surface of a target, using a charged particle beam tool, said tool being capable of generating a plurality of charged particle beams for writing said pattern on said surface, thereby turning off and on each beam separately at writing said pattern onto the surface by means of a blanker part of said system, and of at least in advance of a writing action, sensing characteristics of a writing beam using a sensor included in a position apart from said target surface, characterised in that the sensor is arranged in the system for determination of beam position and/or beam spot size, and for directly detecting all of said writing beams simultaneously, the sensor thereto comprising a converter converting each of said particle beams into a light beam, the sensor further comprising an array of light sensitive elements such as photodiode elements, for detecting such light beams, and for generating an electron charge upon exposure to light, which array is read out at least virtually simultaneously by a calculating unit providing correcting value signals upon such read out to a controller of the particle beam tool, and/or to a controller for said pattern, for modifying electronic data representing said pattern, in which both physical displacement of a beam spot and time delay of a blanking part for blanking a beam are measured, in which the sensor further comprises a blocking element, configured to selectively partially and entirely block a beam, included on top of said converter, and wherein said detector element is applied integrated with said converter element, located on bottom thereof. 
     
     
       28. The system according to  claim 27 , wherein adaptation of the system is performed by at least one of
 electronically modifying electronic data for a pattern to be imaged by said charged particle beam system,   modifying line width, and   electronically influencing a position modifying means of said beam system, for modifying the position of one or more charged particle beams.   
     
     
       29. The System according to  claim 27 , in which the calculating unit based on information from the sensor, provides corrective values for correcting one or more of the position of a particle beam in two directions of a plane substantially parallel to that of the target area, the intensity or current of the particle beam, the spot position and the spot size, and the sigma, of a Gaussian distribution feature of the particle beam. 
     
     
       30. The System according to  claim 27 , in which a particle beam is scanned over said sensor and switched on at an instance where it is expectedly located at a predetermined position. 
     
     
       31. The System according to  claim 30 , in which the beam is switched on for a pre-determined period of time. 
     
     
       32. System according to system  claim 27 , in which multiple scans are performed over the sensor. 
     
     
       33. The System according to  claim 27 , in which a charged particle beam is scanned over the sensor in three different directions. 
     
     
       34. System according to  claim 27 , in which a charged particle beam is scanned for a multiplicity of steps in a single direction over a sensor at different locations, shifted over at least three times an expected or determined spot diameter of the beam. 
     
     
       35. The Lithography system according to  claim 27 , comprising a stage for an object to be processed by a multi beam charged particle tool, said stage being provided with a multiplicity of sensors according to  claim 20 , for measuring charged particle beam features, wherein each sensor of said multiplicity is implemented for measuring all charged particle beams of said tool at a time, and wherein sensors of said multiplicity are distributed at various locations near said object to be processed, at mutual distances that are distributed such that calibration of the beam tool is enabled more than once at entirely treating a wafer. 
     
     
       36. The Lithography system according to  claim 35 , wherein said enabling is realised by distributing at least two sensors at even, at least corresponding distances with respect to the track which the beam tool is to follow relative to said object to be processed. 
     
     
       37. Lithography system according to  claim 35 , wherein the method according to  claim 1 , or the sensor according to  claim 20  is applied. 
     
     
       38. A method of measuring at least one property of individual charged particle beams among a massive amount of charged particle beams (4) of a charged particle beam system substantially simultaneously, said method comprising the steps of:
 scanning each of said charged particle beams (4) during at least one scan over a plurality of sharp edges in at least one direction, wherein said sharp edges form knife-edges and are part of a multiplicity of blocking elements (6) such that the blocking elements are included at known positions relative to a converter element and the charged particle beam by one or more known shifts, wherein said blocking elements are integrated with said converter element and located on a top thereof;   converting the charged particle beams (4) into light beams (5) by using the converter element (1),   using an array of light sensitive detectors (3) located in line with said converter element (1) for detecting said light beams, wherein said converter element and said array of light sensitive detectors form a sensor and the array of light sensitive detectors are integrated with the converter element and located on a bottom thereof,   electronically reading out resulting signals from said detectors (3) after exposure thereof by said light beams (5) to provide a set of measurement data for each charged particle beam individually as it is scanned over said plurality of sharp edges,   wherein said signals are read out substantially simultaneously for all charged particle beams;   for each charged particle beam, mathematically deducting a fit trace from said set of measurement data representing at least one scan over said plurality of sharp edges; and   determining said at least one property for each individual charged particle beam, based on said fit trace.   
     
     
       39. Method according to claim 38, further comprising a step of utilizing said signals for calculating values for one or more charged particle beam properties, thereby using an automated electronic calculator (CU). 
     
     
       40. Method according to claim 38, wherein said at least one property comprises at least one of beam current, beam spot size in the scanning direction, and/or beam spot position. 
     
     
       41. Method according to claim 38, further comprising the step of:
 electronically adapting the charged particle beam system so as to correct for out of specification range values for all or a number of said charged particle beams (4), each for one or more properties, based on said calculated charged particle beam property values.   
     
     
       42. Method according to claim 41 wherein adaptation of the system is performed by at least one of
 electronically modifying electronic data, representing an image pattern forming an instruction basis, for a pattern to be imaged by said charged particle beam system,   modifying line width, and   electronically influencing a position modifying means of said charged particle beam system, for modifying the position of one or more of said charged particle beams.   
     
     
       43. Method according to claim 38, in which values for spot size in at least two directions are used for deriving a spot shape. 
     
     
       44. Method according to claim 38, wherein determination of beam properties is performed on the basis of a plurality of signals resulting from a stepping proceed of a charged particle beam being scanned in one direction at a time over said blocking elements. 
     
     
       45. Method according to claim 38, wherein said charged particle beam system comprises a beam blanker, and wherein said at least one property for a charged particle beam comprises at least one of timing delay information and rise and fall time of said blanker for said beam. 
     
     
       46. Method according to claim 38, in which a beam is switched off and on during such scan. 
     
     
       47. Method according to claim 38, wherein a switching “off” and “on” is incrementally delayed during multiple scans in one direction, relative to a starting point of the scan. 
     
     
       48. Method according to claim 38, wherein a pulse duration variation is determined using a measurement with predetermined beam on/off timing. 
     
     
       49. Method according to claim 38, wherein said at least one property of said charged particle beams includes at least two of charged particle beam position, timing delay of a blanker device acting upon said charged particle beam, beam spot size, beam current and blanking element functioning. 
     
     
       50. Method according to claim 38, wherein said blocking elements are each provided with a sharp edge as taken perpendicularly to the surface of the converter element (1). 
     
     
       51. Method according to claim 38, wherein said plurality of sharp edges are perpendicular to said one direction. 
     
     
       52. Method according to claim 38, wherein the blocking elements are each provided with two sharp edges. 
     
     
       53. Method according to claim 38, wherein said charged particle beams are scanned relative to the sharp edges in at least three different directions. 
     
     
       54. Lithography or inspection system comprising a multi beam charged particle tool adapted for generating multiple charged particle beams (4), said system being provided with a sensor comprising:
 a converter element for converting the charged particle beams (4) into light beams (5),   a multiplicity of blocking elements each comprising a sharp edge forming a knife-edge, for at least partially blocking the charged particle beams, wherein said converter element is applied integrated with said multiplicity of blocking elements and wherein said blocking elements are located on a top of said converter element,   said sensor further comprising an array of light sensitive detectors (3) for detecting said light beams, wherein said array of light sensitive detectors (3) located in line with said converter element and blocking elements and the array of light sensitive detectors are integrated with the converter element and located on a bottom thereof,   said system further comprising:   a deflector for scanning each one of said charged particle beams over a plurality of sharp edges, and   an automated electronic calculator (CU) adapted for calculating one or more charged particle beam property values for each one of said charged particle beams based on signals electronically read out and resulting from said light sensitive detectors (3) after exposure thereof by said light beams (5), wherein said signals provide a set of measurement data for each charged particle beam individually as it is scanned over said plurality of sharp edges,   said electronic calculator being configured to read out said signals substantially simultaneously.   
     
     
       55. Lithography or inspection system according to claim 54, comprising a stage provided with a multiplicity of said sensors, wherein said multiplicity of blocking elements comprises a plurality of sharp edges perpendicular to a scan direction of said stage, wherein each sensor of said multiplicity of sensors is implemented for measuring all charged particle beams of said tool at a time, and wherein sensors of said multiplicity are distributed at various locations near said object to be processed, at mutual distances that are distributed such that calibration of the beam tool is enabled more than once during entire treating a of said object to be processed. 
     
     
       56. Lithography or inspection system according to claim 55, wherein at least two sensors of said multiplicity of sensors are distributed at even, at least corresponding distances with respect to a track which the beam tool is to follow relative to said object to be processed. 
     
     
       57. Lithography or inspection system according to claim 54, wherein said electronic calculator is configured to mathematically deduct a fit trace for each charged particle beam from said set of measurement data representing at least one scan over said plurality of sharp edges, and for determining said at least one property for each individual charged particle beam, based on said fit trace.