Search

CN-122018244-A - Photoetching method for preparing figure edge frame structure in one step

CN122018244ACN 122018244 ACN122018244 ACN 122018244ACN-122018244-A

Abstract

The application belongs to the technical field of micro-nano processing and photoetching, and particularly relates to a photoetching method for preparing a figure edge frame structure in one step. After a photoresist containing a photoacid generator, a polymer and a solvent is coated into a film, single exposure is carried out through a mask, three characteristic areas are spontaneously formed in the film according to acid concentration distribution, wherein the acid concentration of an exposure area is highest, the polymer is triggered to be crosslinked firstly and then hydrolyzed and is soluble in development, the polymer is only crosslinked and insoluble in development in an edge area affected by acid diffusion in an unexposed area, and a core area not affected by acid diffusion in the unexposed area is soluble in development. After development, the soluble areas are synchronously removed, and the insoluble areas are reserved, so that the pattern edge frame structure is directly formed in one step. The method has simple process, does not need multi-step exposure or complex post-treatment, can be used for programmable control of the structure morphology, and is suitable for the fields of micro-electromechanical systems, photon devices, programmable photoetching and the like.

Inventors

  • ZHU MINGQIANG
  • Huang Jundan
  • LI CHONG

Assignees

  • 武汉市太紫微光电科技有限公司

Dates

Publication Date
20260512
Application Date
20260305

Claims (10)

  1. 1. A lithographic method for one-step preparation of a patterned edge frame structure, comprising the steps of: S1, coating a photoresist on the surface of a substrate to form a film; The photoresist comprises a photoacid generator, a polymer and a solvent, wherein the photoacid generator is capable of generating protonic acid under irradiation, the structure of the polymer comprises a cationic crosslinking group capable of initiating a crosslinking reaction by the protonic acid, and the formed crosslinking structure can be subjected to hydrolytic cleavage under the further catalysis of the protonic acid; S2, under the covering of a mask plate, carrying out single exposure on the film, wherein the dosage of the exposure is configured to enable the film to generate the following chemical reactions in a partitioning mode: (a) In the exposed areas, the protonic acid generated by the photoacid generator initiates the polymer to crosslink and then undergo acid-catalyzed hydrolysis, so that the areas are soluble in subsequent development; (b) In the edge area of the unexposed area adjacent to the exposed area, the polymer in the edge area is only subjected to crosslinking reaction under the influence of protonic acid diffused from the exposed area, so that the area is insoluble in subsequent development; (c) In the unexposed area far away from the exposed area, the film material is not affected by the diffusion of proton acid, and the film material does not undergo chemical reaction, so that the area is soluble in subsequent development; S3, placing the film exposed in the step S2 into a developing solution for one-time development, synchronously dissolving the exposed area and an unexposed area which is not affected by proton acid diffusion, and reserving the edge area of the unexposed area, thereby directly forming a pattern edge frame structure.
  2. 2. The method according to claim 1, wherein in step S1, the polymer is poly-2, 3-dihydrofuran having a number average molecular weight of 10 to 30 tens of thousands.
  3. 3. The method according to claim 1, wherein in step S1, the photoacid generator is one or more of iodonium salt, sulfonium salt, o-nitrobenzyl sulfonate, iminosulfonate, and N-hydroxy iminosulfonate.
  4. 4. The method according to claim 1, wherein in step S1, the solvent is one or more of ethyl acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate, and γ -butyrolactone.
  5. 5. The method according to any one of claims 1 to 4, wherein in step S1, the polymer is used in an amount of 1wt% to 10wt% based on the mass of the solvent, and the photoacid generator is used in an amount of 10wt% to 40wt% based on the mass of the polymer.
  6. 6. The method according to claim 1, wherein in step S2, the thin film is baked at 90 ℃ to 120 ℃ for 1 to 2min before exposure.
  7. 7. The method according to claim 1, wherein in step S2, the dose of the single exposure is 300mJ/cm 2 ~2000mJ/cm 2 .
  8. 8. The method according to claim 1, wherein in step S3, the developing solution is ethyl acetate.
  9. 9. A patterned edge frame structure produced by the lithographic method of any one of claims 1 to 8.
  10. 10. A micro-nano device comprising the patterned edge frame structure of claim 9.

Description

Photoetching method for preparing figure edge frame structure in one step Technical Field The application belongs to the technical field of microelectronic device processing, and particularly relates to a photoetching method for preparing a figure edge frame structure in one step. Background The fine pattern processing under the micro-nano scale is the basis of the fields of semiconductors, micro-electro-mechanical systems (MEMS), photonic devices, advanced packaging and the like. As a core means of patterning, the photoresist (photoresist), which is a key material, is mainly classified into positive photoresist and negative photoresist according to the relationship between the developed pattern and the reticle. In recent years, in order to improve process flexibility, "positive and negative inversion" or "double tone" photoresists have emerged. Such materials can be used to obtain positive or negative patterns on the same coating liter by varying the exposure or post-treatment process conditions, respectively. However, the existing inversion techniques still largely follow the pattern replication pattern of the mask layout and generally rely on complex multi-step process flows, such as low dose exposure and bake to form a latent image followed by blanket exposure and differential development, requiring precisely controlled multiple exposure, additional post-exposure bake steps. These processes have a large number of steps and sensitive control parameters (such as baking temperature and time), increase process complexity and cost, impose additional requirements on equipment, and limit processing efficiency and stability. Of particular concern in the fabrication of functionalized micro-nano devices (e.g., optical resonators, sensors, metamaterial units), it is often desirable to obtain reticle pattern edge frame structures that go beyond simple geometric replication, such as isolated ring, frame or cofferdam edge structures. The preparation of the pattern edge frame structure by using the traditional photoetching technology faces the fundamental challenges that if the traditional positive photoresist or negative photoresist technology is adopted, a complex mask plate which completely corresponds to the geometric shape of the pattern edge frame structure needs to be designed and manufactured, the cost is high, if the structure is combined by carrying out photoetching and alignment for multiple times through a plurality of masks, the technology integration level is low, the alignment precision requirement is extremely high, the yield is difficult to ensure, and the gray scale mask or electron beam direct writing technology can be realized, but the equipment is expensive and the efficiency is low. Therefore, there is a strong need in the art for a lithographic method that can directly form a pattern edge frame structure in one step from a base mask pattern without requiring a complex reticle or multi-step overlay process, with simple and efficient process, and without requiring complex post-processing steps. Disclosure of Invention Aiming at the defects of the prior art, the application aims to provide a photoetching method for preparing a graph edge frame structure in one step, and aims to solve the problems that the existing positive and negative reversal photoetching is limited by a mask copying mode and can not realize the graph from a mask graph to the graph edge frame structure, the existing preparation process of the graph edge frame structure is complex, the graph edge frame structure can be realized only through multiple times of photoetching, etching or complex gray scale mask technology, the process integration level is low, the overlay precision requirement is high and the like. To achieve the above object, in a first aspect, the present application provides a photolithography method for preparing a pattern edge frame structure in one step, comprising the steps of: S1, coating a photoresist on the surface of a substrate to form a film; The photoresist comprises a photoacid generator, a polymer and a solvent, wherein the photoacid generator is capable of generating protonic acid under irradiation, the structure of the polymer comprises a cationic crosslinking group capable of initiating a crosslinking reaction by the protonic acid, and the formed crosslinking structure can be subjected to hydrolytic cleavage under the further catalysis of the protonic acid; s2, under the covering of a mask plate, carrying out single exposure on the film, wherein the exposure dose is configured to enable the film to generate the following chemical reactions in a partitioning mode: (a) In the exposed areas, the protonic acid generated by the photoacid generator initiates the polymer to crosslink and then undergo acid-catalyzed hydrolysis, so that the areas are soluble in subsequent development; (b) In the edge area of the non-exposure area adjacent to the exposure area, the polymer in the edge area only undergoes a cro