# US 5,892,231 A · Virtual mask digital electron beam lithography > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,892,231 A - Document ID: US5892231A - Status: Granted - Kind: A - Application number: 08/795,003 - Filed: 1997-02-05 - Granted: 1999-04-06 - Earliest claimed: 1997-02-05 - Assignees: Lockheed Martin Energy Research Corporation - Inventors: Larry R. Baylor; Clarence E. Thomas; Edgar Voelkl; James A. Moore; Michael L. Simpson; Michael J. Paulus - Web page: https://patentgrep.com/patent/US5892231A ## CPC - H01J 37/3175: {Projection methods, i.e. transfer substantially complete pattern to substrate} - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - B82Y 40/00: Manufacture or treatment of nanostructures - H01J 2237/31786: Field-emitting cathode - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made. ## Claims ### Claim 1 A digital direct write electron beam lithography system, comprising: I) a digitally addressable field emission array including: A) a digital computer interface; B) a plurality of field emitters electrically connected to said digital computer interface, each of said plurality of individually addressable field emitters having an individual bias; and C) an electrostatic bias grid operably connected to said plurality of field emitters; II) an electrostatic accelerator grid operably connected to said addressable field emission array; III) a magnetic lens assembly operably connected to said electrostatic accelerator grid, said magnetic lens assembly including: A) a telecentric magnetic lens system; and B) a correction magnetic lens system; and IV) a set of electrostatic deflection plates operably connected to said magnetic lens assembly. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising V) a target wafer electronically coupled to said plurality of individually addressable field emitters through all of said electrostatic accelerator grid, said magnetic lens assembly and said set of electrostatic deflection plates. ### Claim 3 An apparatus, comprising; a digitally addressable field emission array, each of said plurality of individually addressable field emitters having an individual bias; an electrostatic accelerator grid operably connected to said addressable field emission array; and a magnetic lens assembly operably connected to said addressable field emitter array. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein said digitally addressable field emitter array includes: A) a digital computer interface; and B) an electrostatic bias grid operably and individually connected to said plurality of individually addressable field emitters, wherein said digitally addressable field emission array is electrically coupled to said digital computer interface. ### Claim 5 (depends on 3) The apparatus of claim 3, wherein said magnetic lens assembly includes a telecentric magnetic lens system and a correction lens system. ### Claim 6 (depends on 3) The apparatus of claim 3, further comprising a set of electrostatic deflection plates operably connected to said magnetic lens assembly. ### Claim 7 (depends on 3) The apparatus of claim 3, further comprising a target wafer electronically coupled to said digitally addressable field emitter array. ### Claim 8 (depends on 3) A stepper comprising the apparatus of claim 3. ### Claim 9 An apparatus comprising: means for generating a spatially modulated electron beam matrix, each of said plurality of individually addressable field emitters having an individual bias; and means for focusing said spatially modulated electron beam matrix. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein said means for focusing includes means for de-magnifying said electron beam matrix. ### Claim 11 (depends on 9) The apparatus of claim 9, further comprising means for applying an electrostatic field to said spatially modulated electron beam matrix so as to accelerate said spatially modulated electron beam matrix and reduce distortions of said spatially modulated electron beam matrix caused by electromagnetic aberrations generated by said means for focusing. ### Claim 12 (depends on 9) The apparatus of claim 9, further comprising means for applying an electrostatic field to said spatially modulated electron beam matrix so as to deflect said spatially modulated electron beam matrix and permit complete writing of a plurality of pixels by said spatially modulated electron beam matrix. ### Claim 13 A method, comprising: programming a addressable field emitter array, each of said plurality of individually addressable field emitters having an individual bias; and then producing a spatially modulated electron beam matrix with said addressable field emitter array; and focusing said spatially modulated electron beam matrix with a magnetic lens assembly. ### Claim 14 (depends on 13) The method of claim 13, further comprising accelerating said spatially modulated electron beam matrix with an electrostatic acceleration structure. ### Claim 15 (depends on 13) The method of claim 13, further comprising deflecting said spatially modulated electron beam matrix with an electrostatic deflection structure. ### Claim 16 (depends on 13) The method of claim 13, further comprising writing an electron resist with said spatially modulated electron beam matrix. ### Claim 17 (depends on 13) The method of claim 13, further comprising reprogramming said digitally addressable field emitter array. ### Claim 18 (depends on 13) In a lithographic process, the improvement comprising the method of claim 13. ### Claim 19 (depends on 13) An apparatus for performing the method of claim 13. ### Claim 20 (depends on 13) An apparatus made by the method of claim 13.