# US 8,541,164 B2 · Sub-wavelength lithography via Rabi oscillations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,164 B2 - Document ID: US8541164B2 - Status: Granted - Kind: B2 - Application number: 13/270,597 - Filed: 2011-10-11 - Published: 2013-01-03 - Granted: 2013-09-24 - Earliest claimed: 2011-06-30 - Assignees: The Texas A&M University System; King Abdulaziz City for Science and Technology - Applicants: Mohammad D. Al-Amri; Zeyang Liao; Muhammad Suhail Zubiary - Inventors: Mohammad D. Al-Amri; Zeyang Liao; Muhammad Suhail Zubiary - Web page: https://patentgrep.com/patent/US8541164B2 ## CPC - G03F 7/20: Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00) - G03F 7/70408: {Interferometric lithography; Holographic lithography; Self-imaging lithography, e.g. utilizing the Talbot effect} - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) ## Abstract A sub-wavelength photolithographic method includes exposing a photoresist material to a stimulating electromagnetic source prior to further exposing the photoresist material to a dissociating electromagnetic source. The stimulating electromagnetic source induces Rabi oscillations in the photoresist material between a first molecular state and an excited molecular state. The subsequent exposure of the photoresist material to the dissociating electromagnetic source dissociates only those molecules that are in the excited state, altering the properties of the photoresist material in zones of excited state molecules. The resulting patterns therefore depend on the spatial distribution of the zones of excited state molecules induced by the stimulating electromagnetic source. The properties of the stimulating electromagnetic source are controlled to achieve a desired spatial distribution of zones of excited state molecules of the photoresist material. ## Claims ### Claim 1 A photolithographic method, comprising: directing two or more first electromagnetic source pulses on a photoresist material, the two or more first electromagnetic source pulses interfering to induce oscillations in the photoresist material by which a first plurality of zones of the photoresist material are in a first state and a second plurality of zones of the photoresist material are in an excited state; and exposing the photoresist material to a second electromagnetic source, wherein the second electromagnetic source initiates a reaction of the second plurality of zones but does not initiate a reaction of the first plurality of zones. ### Claim 2 (depends on 1) The photolithographic method of claim 1, wherein the oscillations in the photoresist material are Rabi oscillations. ### Claim 3 (depends on 1) The photolithographic method of claim 1, wherein the two or more first electromagnetic source pulses are Gaussian pulses. ### Claim 4 (depends on 3) The photolithographic method of claim 3, wherein the Gaussian pulses have the same amplitude and duration. ### Claim 5 (depends on 1) The photolithographic method of claim 1, wherein the two or more first electromagnetic source pulses are of a same frequency. ### Claim 6 (depends on 5) The photolithographic method of claim 5, wherein the frequency is resonant with an energy difference between the first state and the excited state of the photoresist material. ### Claim 7 (depends on 1) The photolithographic method of claim 1, wherein the second plurality of zones are disposed over a two dimensional region of the photoresist material. ### Claim 8 (depends on 1) The photolithographic method of claim 1, wherein the photoresist material is exposed to the second electromagnetic source within a phosphorescence time of the photoresist material. ### Claim 9 (depends on 1) The photolithographic method of claim 1, wherein the two or more first electromagnetic source pulses are laser pulses. ### Claim 10 A photolithographic method, comprising: directing two pulses of a stimulating electromagnetic source on a photoresist material, the pulses forming a standing electric field that induces one or more zones of the photoresist material into an excited state; and exposing the photoresist material to a dissociating electromagnetic source, wherein the dissociating electromagnetic source initiates a reaction of the photoresist material only in the one or more zones of the photoresist material that are in the excited state. ### Claim 11 (depends on 10) The photolithographic method of claim 10, wherein the two pulses of the stimulating electromagnetic source are Gaussian pulses. ### Claim 12 (depends on 11) The photolithographic method of claim 11, wherein the Gaussian pulses have the same amplitude and duration. ### Claim 13 (depends on 10) The photolithographic method of claim 10, wherein the two pulses of the stimulating electromagnetic source are of a same frequency. ### Claim 14 (depends on 13) The photolithographic method of claim 13, wherein the frequency is resonant with an energy difference between a first state and the excited state of the photoresist material. ### Claim 15 (depends on 10) The photolithographic method of claim 10, wherein the photoresist material is exposed to the dissociating electromagnetic source within a phosphorescence time of the photoresist material. ### Claim 16 (depends on 10) The photolithographic method of claim 10, wherein the two pulses of the stimulating electromagnetic source are laser pulses. ### Claim 17 (depends on 10) The photolithographic method of claim 10, wherein the two pulses of the stimulating electromagnetic source are from opposite directions. ### Claim 18 (depends on 17) The photolithographic method of claim 17, wherein the two pulses of the stimulating electromagnetic source are directed on to the photoresist material from a same angle with respect to a plane of the photoresist material. ### Claim 19 (depends on 10) The photolithographic method of claim 10, further comprising a third pulse of the stimulating electromagnetic source that provides a constant background to the standing electric field. ### Claim 20 (depends on 19) The photolithographic method of claim 19, wherein an amplitude of the third pulse of the stimulating electromagnetic source alters a location of the one or more zones of the photoresist material that are in the excited state.