Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • 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
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/0002—Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping

Definitions

• Embodiments of the disclosure relate to methods of producing three-dimensional patterns, particularly for producing master templates, e.g. master templates used for fabrication of imprint stamps.
• embodiments of the disclosure relate to methods of producing multilevel three- dimensional patterns for providing an multilevel imprint master usable for production of an imprint stamp, e.g. for imprint lithography.
• Patterning of thin films is desired for a plurality of applications, for example manufacturing of microelectronic devices, optoelectronic devices, or optical devices.
• Optical lithography techniques may be used for patterning thin films in a device.
• optical lithography techniques may be expensive and/or may reach limits particularly on substrates having larger sizes.
• the master template for transferring the structure of the master template to an imprint stamp, can be coated with a polymer layer. After separation of the polymer layer from the master template, the surface of the polymer layer includes the inverse structure of the negative master template structure. The structured polymer layer can then be used for providing the imprint structure of an imprint stamp.
• imprint masters There are several technical challenges with respect to manufacturing imprint masters. In particular, producing multilevel masters in which sidewall angle and depth uniformity of master structure features can be ensured across many depths remains challenging. Further, producing masters with a three-dimensional structure having features with high aspect ratios and/or a wide range of depth which provide for high structural accuracy is the key for manufacturing high accuracy stamps, e.g. for imprint lithography.
• a method for producing a multilevel imprint master includes providing a substrate having a main surface providing a first level and creating a first set of features in the substrate.
• the first set of features provides a second level being below the first level.
• the method includes creating a second set of features on the substrate.
• the second set of features provides a third level being above the first level.
• a method for producing a multilevel imprint master includes providing a substrate and coating the substrate with a first layer of a first photo resist material.
• the first layer has a main surface providing a first level.
• the method includes creating a first set of features in the first layer.
• the first set of features provides a second level being below the first level.
• the method includes creating a second set of features on the main surface of the first layer.
• the second set of features provides a third level being above the first level.
• a multilevel imprint master is provided, the multilevel imprint master being produced by a method according to any embodiments described herein.
• a use of a multilevel imprint master according to any embodiments described herein for production of an imprint stamp is provided.
• Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner.
• FIGS. lA to 1C show schematic illustrations of exemplary method stages of a method for producing a multilevel imprint master according to embodiments described herein;
• FIGS. 2 A to 2F show schematic illustrations of exemplary method stages of a method for producing a multilevel imprint master according to further embodiments described herein;
• FIGS. 3 A to 3E show schematic illustrations of exemplary method stages of a method for producing a multilevel imprint master according to yet further embodiments described herein;
• FIGS. 4A and 4B show flowcharts for illustrating embodiments of a method for producing a multilevel imprint master according to embodiments described herein.
• the method includes providing a substrate 10 having a main surface 10A providing a first level 11, as exemplarily shown in FIG. 1A.
• the procedure of providing a substrate 10 having a main surface 10A providing a first level 11 is exemplarily represented by block 210 in FIG. 4A showing a flowchart of a method 200 for producing a multilevel imprint master according to embodiments described herein.
• the first level 11 corresponds to the level of the main surface 10A.
• the main surface 10A is the upper surface of the substrate 10.
• a substrate as described herein is a flat substrate, e.g. a plate or a disk.
• the substrate as described herein can include or consist of a material selected from the group consisting of a semiconductor, silicon, quartz or glass.
• the method includes creating a first set 21 of features in the substrate 10.
• the term “creating” can be understood as “fabricating”, “manufacturing” or“producing”.
• the procedure of creating a first set 21 of features in the substrate 10 is exemplarily represented by block 220 in FIG.4A.
• the first set 21 of features provides a second level 12 being below the first level 11.
• the second level 12 is substantially parallel to the first level 11.
• the term“substantially parallel” can be understood as parallel with some degree of tolerance, e.g. a deviation from parallelism by ⁇ 2°, particularly ⁇ 1°, more particularly ⁇ 0.5°.
• the first set 21 of features extend from the first level 11 to the second level 12. More specifically, the first set 21 of features typically have a depth D.
• the depth D can be regarded as the distance of the second level 12 from the first level 11.
• the first set 21 of features may include one or more features selected from the group consisting of a recess, a cavity, a groove or a hole.
• the first set 21 of features typically include sidewalls 21 S and bottom walls 21B.
• the sidewalls 21 S extend form the main surface 10A of the substrate 10 to the bottom walls 21B.
• the sidewalls 21 S are substantially perpendicular to the main surface 10A of the substrate 10.
• the term“substantially perpendicular” can be understood as perpendicular with some degree of tolerance, e.g. a deviation from perpendicularity by ⁇ 2°, particularly ⁇ 1°, more particularly ⁇ 0.5°.
• the bottom walls 21B are typically substantially parallel to the main surface 10A of the substrate 10. As exemplarily shown in FIG. 1B, the length of the sidewalls 21 S of the first set 21 of features typically corresponds to the depth D. As can be seen from FIG. 1B, the bottom walls 21B of the first set 21 of features typically corresponds to the second level 12.
• creating the first set 21 of features in the substrate 10 typically includes removing material of the substrate.
• the method includes creating a second set 22 of features on the substrate 10.
• the procedure of creating a second set 22 of features on the substrate 10 is exemplarily represented by block 230 in FIG.4A.
• the second set 22 of features provide a third level 13 being above the first level 11.
• the third level 13 is substantially parallel to the first level 11.
• the second set 22 of features extend from the first level 11 to the third level 13.
• the second set 22 of features typically have a height H.
• the height H can be regarded as the distance of the third level 13 from the first level 11.
• the second set 22 of features may include one or more features selected from the group consisting of a protrusion, a bar, a pillar, or other geometries extending from the main surface 10A of the substrate 10 up to the third level 13.
• the first set 21 of features typically include sidewalls 22 S and top walls 22T.
• the sidewalls 22 S extend form the main surface 10A of the substrate 10 to the top walls 22T.
• the sidewalls 22S are substantially perpendicular to the main surface 10A of the substrate 10.
• the top walls 22T are typically substantially parallel to the main surface 10A of the substrate 10.
• the length of the sidewalls 22S of the second set 22 of features typically corresponds to the height H.
• the top walls 22T of the second set 22 of features typically corresponds to the third level 13.
• creating the second set 22 of features on the substrate 10 typically includes adding material on the substrate.
• embodiments of the method for producing a multilevel imprint master as described herein are improved compared to conventional methods.
• embodiments of the present disclosure beneficially provide a hybrid method, i.e. a method including a material removal procedure and a material addition procedure.
• a hybrid production method as described herein has the advantage that the structure of the multilevel imprint master can be fabricated with higher accuracy.
• combining a material removal procedure with a subsequent material addition procedure beneficially provides for the possibility to create the features of the imprint master with a higher resolution, better uniformity and better accuracy compared to features obtained by conventional methods.
• embodiments of the method as described herein are particularly well suited for producing an imprint master having three (or more) levels, wherein a first set of features provided on the first level are relatively densely populated relative to the population of a further set of features on a further level, e.g. a second set of features on a third level as described herein. More specifically, creating the first set of features by using a subtractive process, i.e. material removal procedure, and creating the second set of features by using an additive process, i.e. a material addition procedure, has the advantage that the second set of features can be created independent of height and feature size of the first set of features.
• a subtractive process i.e. material removal procedure
• an additive process i.e. a material addition procedure
• methods of the present disclosure beneficially provide for the possibility to produce imprint masters with higher feature densities and an increased total range of feature heights.
• embodiments of the present disclosure beneficially provide for creating features having improved feature sidewall angle uniformity and depth uniformity, particularly across multiple depths. Accordingly, beneficially high quality multilevel imprint masters can be produced.
• creating the first set 21 of features includes providing a first mask 31 having a pattern on the substrate 10, as exemplarily shown in FIG. 2A.
• the first mask 31 can be provided to be in direct contact with the main surface 10A of the substrate.
• the first mask 31 includes the pattern to be transferred into the substrate 10.
• the first mask 31 typically functions as a template for creating the first set 21 of features in the substrate 10.
• creating the first set 21 of features can include transferring the pattern of the first mask into the substrate 10, for example by employing an etching process.
• the etching process can be a wet etching process.
• a wet etching process can be understood as a process of material removal, e.g. a masked pattern of material, by using liquid-phase (“wet") etchants.
• the etching process can be a dry etching process.
• a dry etching process can be understood as a process of material removal, e.g. a masked pattern of material, by exposing the material to a bombardment of ions.
• the bombardment of ions can be provided by a plasma of reactive gases (e.g. fluorocarbons, oxygen, chlorine, or boron trichloride optionally with the addition of nitrogen, argon, helium and other gases) dislodging portions of the material from the exposed surface.
• reactive gases e.g. fluorocarbons, oxygen, chlorine, or boron trichloride optionally with the addition of nitrogen, argon, helium and other gases
• the first mask 31 is removed from the substrate, such that the main surface 10A of the substrate 10 is exposed, as exemplarily shown in FIG. 2C.
• creating the second set 22 of features includes coating the substrate 10 with a photoresist layer 40.
• coating the substrate with the photoresist layer may include using a spin coating process.
• the photoresist layer 40 is provided over the substrate 10.
• the photoresist layer 40 fills out the first set 21 of features provided in the substrate 10 and covers the main surface 10A of the substrate 10.
• an upper surface 40 A of the photoresist layer 40 typically provides the third level 13.
• creating the second set 22 of features typically includes patterning the photoresist layer 40.
• patterning the photoresist layer 40 may include exposing the photoresist layer to light through a second mask 32, as exemplarily shown in FIG. 2E.
• creating the second set 22 of features typically includes applying a photoresist developer to the photoresist layer 40, particularly the surface of the photoresist layer 40.
• the photoresist can be a positive photoresist.
• a positive photoresist can be understood as a type of photoresist in which the portion of the photoresist that is exposed to light becomes soluble to a photoresist developer. The unexposed portion of the positive photoresist remains insoluble to the photoresist developer.
• the photoresist can be a negative photoresist.
• a negative can be understood as a type of photoresist in which the portion of the photoresist that is exposed to light becomes insoluble to a photoresist developer. The unexposed portion of the photoresist is dissolved by the photoresist developer.
• a negative photoresist is used, i.e. the photoresist layer 40 includes or consists of a negative photoresist.
• a positive photoresist can be used, i.e. the photoresist layer 40 can include or consist of a positive photoresist.
• the second mask 32 may be adapted accordingly. In particular, in order to create a second set 22 of features as exemplarily shown in FIG. 2F by using a positive photoresist, the second mask 32 would be an inverse mask of the mask shown in FIG. 2E,
• a multilevel imprint master 100 as exemplarily shown in FIG. 2F can be produced by embodiments of the method as described herein.
• the method includes providing a substrate 10, as exemplarily shown in FIG. 3 A.
• the procedure of providing a substrate 10 is exemplarily represented by block 310 in FIG. 4B showing a flowchart of a further method 300 for producing a multilevel imprint master according to embodiments described herein.
• the method includes coating the substrate 10 with a first layer 51 of a first photo resist material, as exemplarily shown in FIG. 3B.
• the procedure of coating the substrate 10 with a first layer 51 of a first photo resist material is exemplarily represented by block 320 in FIG. 4B.
• the first layer 51 of a first photo resist material is typically provided to be in direct contact with the main surface 10A of the substrate 10.
• coating the substrate 10 with the first layer 51 of a first photo resist material may include using a spin coating process.
• the first layer of first photo resist material has a first main surface 51A providing a first level 11.
• the first main surface 51A of the first layer 51 of first photo resist material i.e. the upper surface of the first layer 51 of first photo resist material, is substantially parallel to the main surface 10A of the substrate 10.
• the method includes creating a first set 21 of features in the first layer 51 of a first photo resist material.
• the procedure of creating a first set 21 of features in the first layer 51 of a first photo resist material is exemplarily represented by block 330 in FIG. 4B.
• the first set 21 of features provide a second level 12 being below the first level 11.
• the first set 21 of features in the first layer 51 of first photo resist material extend from the first level 11 to a second level 12.
• the second level 12 corresponds to the level of the main surface 10A of the substrate 10.
• the first set 21 of features in the first layer 51 of first photo resist material typically have a depth D.
• the depth D can be regarded as the distance of the second level 12 from the first level 11.
• the first set 21 of features in the first layer 51 of a first photo resist material may include one or more features selected from the group consisting of a recess, a cavity, a groove or a hole.
• the first set 21 of features in the first layer 51 of the first photo resist material typically include sidewalls 21 S and bottom walls 21B.
• the sidewalls 21 S extend form the first main surface 51A of the first layer 51 of a first photo resist material to the bottom walls 21B.
• the bottom walls 21B typically correspond to the main surface 10A of the substrate 10.
• the the sidewalls 21 S are typically substantially perpendicular to the first main surface 51 A of the first layer 51 of first photo resist.
• the bottom walls 21B of the first set 21 of features are typically substantially parallel to the first main surface 51A of the first layer 51 of first photo resist material.
• the length of the sidewalls 21 S of the first set 21 of features typically corresponds to the depth D.
• the bottom walls 21B of the first set 21 of features in the first layer 51 of a first photo resist material typically corresponds to the second level 12.
• creating the first set 21 of features in the first layer 51 of the first photo resist material typically includes removing material of the first layer 51.
• creating the first set 21 of features in the first layer 51 of the first photo resist material includes providing a first mask 31 over the first layer 51 of first photo resist material.
• the first mask 31 can be a first photomask.
• creating the first set 21 of features in the first layer 51 of the first photo resist material includes patterning the first layer 51.
• patterning the first layer 51 may include exposing the first layer 51 of first photo resist material to light through the first mask 31, as exemplarily shown in FIG. 3B.
• the first photo resist material can be a positive photoresist.
• creating the first set 21 of features in the first layer 51 of the first photo resist material typically includes applying a photoresist developer to the first photo resist material, particularly the first main surface 51A of the first layer 51.
• the method includes creating a second set 22 of features on the first main surface 51A of the first layer 51 of the first photo resist material.
• the second set 22 of features provide a third level 13 being above the first level 11.
• the procedure of creating a second set 22 of features on the first main surface 51A of the first layer 51 is exemplarily represented by block 340 in FIG. 4B.
• the third level 13 is substantially parallel to the first level 11.
• the second set 22 of features provided on the first main surface 51A of the first layer 51 of the first photo resist material extend from the first level 11 to the third level 13.
• the second set 22 of features typically have a height H.
• the height H can be regarded as the distance of the third level 13 from the first level 11.
• creating the second set 22 of features includes coating the first layer 51 with a second layer 52 of a second photoresist material.
• the second photoresist material has the opposite light sensitivity to the first photoresist material.
• the second photoresist material is a negative photoresist.
• coating the first layer 51 with a second layer 52 of a second photoresist material may include using a spin coating process.
• the second layer 52 of second photo resist material has a second main surface 52A providing a third level 13. The third level 13 is above the first level 11.
• the second main surface 52A of the second layer 52 of second photo resist material i.e. the upper surface of the second layer 52 of second photo resist material, is substantially parallel to the main surface 10A of the substrate 10.
• creating the second set 22 of features typically includes patterning the second layer 52 of second photoresist material.
• patterning the second layer 52 can include exposing the second layer 52 to light through a second mask 32, particularly a second photomask, as exemplarily shown in FIG. 3D.
• Further creating the second set 22 of features typically includes applying a photoresist developer to the second photo resist material, particularly the second main surface 52A of the second layer 52.
• creating the second set 22 of features on the first layer 51 of first photo resist material typically includes adding material on the first main surface 51 A of the first layer 51.
• the first photoresist material can be a positive photoresist and the second photoresist material can be a negative photoresist.
• the first photoresist material can be a negative photoresist and the second photoresist material can be a positive photoresist.
• a multilevel imprint master 100 as exemplarily shown in FIG. 3E can be produced by embodiments of the method as described herein.
• the principles of the method for producing a multilevel imprint master as described herein are not restricted to a three level imprint master.
• an imprint master having more than three levels can be produced.
• a fourth set of features providing a fourth level can be produced.
• a fifth set of features providing a fifth level can be produced.
• an N- level imprint master can be provided, wherein N is selected form a range of 3 ⁇ N ⁇ 50.
• a use of a multilevel imprint master according to any embodiments described herein for production of an imprint stamp is provided.
• the multilevel imprint master provides a negative template of the structure to be transferred to the imprint stamp.
• the multilevel imprint master is typically coated with a polymer material, particularly a curable polymer material, to form a positive template.
• a curable polymer material can be understood as a polymer which can be cured by application of heat and/or radiation and/or addition of chemicals.
• a curable polymer material can be understood as a polymer material which can be toughened or hardened by cross-linking of polymer chains, e.g. induced by heat, radiation or chemical additives.
• the positive template is separated from the multilevel imprint master.
• the positive template can be attached to a stamp support structure.
• the stamp support structure is a mechanical structure, e.g. a plate or a roller, configured for supporting the positive template including the imprint structure to be imprinted.
• embodiments of a method for producing a multilevel imprint master and an improved multilevel imprint master can be provided.
• embodiments of the present disclosure beneficially provide a hybrid method, i.e. a method including a material removal procedure and a material addition procedure.
• a hybrid production method as described herein beneficially provides for the possibility to create the features of the imprint master with a higher resolution, better uniformity and better accuracy compared to features obtained by conventional methods.
• a multilevel imprint master with features having improved feature sidewall angle uniformity and depth uniformity, particularly across multiple depths can be provided. Accordingly, improved multilevel stamps, particularly improved multilevel stamps for imprint lithography imprint, can be produced by using a multilevel imprint master produced by a method according to embodiments described herein.

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• 2018
  • 2018-03-26 WO PCT/EP2018/057646 patent/WO2019185110A1/en active Application Filing
  • 2018-03-26 CN CN201880090964.6A patent/CN112219164A/zh active Pending
• 2019
  • 2019-03-26 TW TW108110459A patent/TWI711881B/zh not_active IP Right Cessation

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