Soft mold for nanoimprint
By incorporating a flexible substrate, an imprinting adhesive layer, a catalyst layer, a metal plating layer, and a release layer into the soft mold, the mechanical properties and stability issues of existing soft molds in the nanoimprinting process are solved, achieving high-quality imprinting effects and extended service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2026-03-10
AI Technical Summary
Existing soft molds have problems such as poor mechanical properties, low surface curing degree, easy breakage, reaction with the imprinted material, and large structural deviations when used multiple times, resulting in unstable imprinting quality.
The soft mold structure consists of a flexible substrate, an imprinting adhesive layer, a catalyst layer, a metal plating layer, and a release layer, arranged sequentially. The thickness of each layer is controlled to improve surface smoothness and mechanical properties. The catalyst layer and the metal plating layer isolate the imprinting adhesive layer from the imprinted material, and the metal plating layer enhances the interface strength.
It improves the surface flatness of the soft mold, reduces the scrap rate caused by surface defects in the embossing structure, significantly improves the mechanical properties and service life of the soft mold, and ensures the stability of the embossing effect.
Smart Images
Figure CN223986277U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of nanoimprinting, and more specifically to a soft mold for nanoimprinting. Background Technology
[0002] The mold is the biggest difference between nanoimprint lithography (NIL) and traditional optical lithography. As the initial carrier of the imprinted features, the mold directly determines the quality of the imprinted pattern. To achieve high-quality imprint replicas, a high-quality imprint mold is essential. Unlike the masks (4X) used in traditional optical lithography, nanoimprint lithography uses 1X molds, which presents greater challenges in mold fabrication, inspection, and repair.
[0003] Currently, many research teams are dedicated to the research of soft molds. Soft molds generally refer to molds made of soft materials as the matrix. They typically use photoresist as a prepolymer, employing imprinting technology to create patterns on its surface, and then curing it through thermosetting or UV light to obtain a polymer soft mold that replicates the pattern. Compared to hard molds, soft molds not only have a simpler manufacturing process, significantly reducing costs, but they can also compensate for differences in surface morphology, overcoming the inflexibility of rigid materials and greatly improving the quality and area of the imprinted pattern. However, conventional soft molds currently suffer from poor mechanical properties and low surface curing, leading to defects in surface flatness and a high risk of breakage during imprinting, especially when imprinting high-refractive-index nanoimprinting adhesives. The nanoimprinting structure is prone to breakage, resulting in imprinting failure. Furthermore, the adhesive layer on the surface of the soft mold easily reacts with the nanoimprinting adhesive being imprinted, exacerbating the risk of imprinting failure. In addition, soft molds with low mechanical properties are also prone to deformation during repeated use, resulting in significant deviations in the shape retention rate of the imprinted structure between batches.
[0004] Therefore, in order to meet market demand, it is necessary to design a new soft mold with excellent mechanical properties. Utility Model Content
[0005] Therefore, the technical problem to be solved by this application is to overcome the above-mentioned defects in the prior art. Its purpose is to provide a soft mold for nanoimprinting, which has high surface flatness and excellent mechanical properties by sequentially arranging a flexible substrate, an imprinting adhesive layer, a catalyst layer, a metal plating layer, and a release layer.
[0006] A first aspect of this application provides a soft mold for nanoimprinting, wherein the soft mold comprises, in the thickness direction,:
[0007] A flexible substrate, said flexible substrate being made of a material that can transmit ultraviolet light;
[0008] An embossing adhesive layer is located on the surface of the flexible substrate. The embossing adhesive layer includes equally spaced parallel protrusions, and the thickness of the embossing adhesive layer is greater than the thickness of the protrusions.
[0009] A catalyst layer is located on the surface of the imprinted adhesive layer on the side away from the flexible substrate;
[0010] A metal coating is located on the surface of the catalyst layer away from the flexible substrate, and the thickness of the metal coating is greater than the thickness of the catalyst layer;
[0011] A release layer is located on the surface of the metal plating layer away from the flexible substrate, and the thickness of the release layer is less than the thickness of the metal plating layer;
[0012] The sum of the thicknesses of the catalyst layer, the metal plating layer, and the release layer is not less than 500 nm.
[0013] In this application, a catalyst layer, a metal plating layer, and a release agent layer are sequentially disposed on the imprinting adhesive layer, and the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release agent layer is controlled to be no less than 500 nm. This not only effectively isolates the reaction between the imprinting adhesive layer and the UV-cured material being imprinted during the nanoimprinting process, thus preventing imprinting process failure, but also ensures the smoothness of the soft mold surface by setting the metal plating layer and controlling its thickness to be greater than that of the release agent layer. This reduces the scrap rate caused by surface defects in the imprinted structure, ensuring the imprinting effect. More importantly, the metal plating layer can significantly improve the interface strength, thereby improving the mechanical properties of the soft mold and increasing its service life.
[0014] In any embodiment, the thickness of the imprinting adhesive layer is 5nm~30μm, optionally 50nm~20μm, and the imprinting adhesive layer is prepared by photocuring imprinting adhesive.
[0015] In any embodiment, the thickness of the catalyst layer is 100nm~500nm, optionally 150nm~400nm, and the porosity of the catalyst layer is not higher than 10%, optionally not higher than 8%.
[0016] In any embodiment, the thickness of the metal coating is 300nm~800nm, optionally 400nm~800nm, and the metal coating includes at least one of gold, silver, and copper.
[0017] In any embodiment, the thickness of the protrusion is 1nm~25nm, optionally 5nm~25nm, and the width is 1nm~10nm, optionally 3nm~8nm.
[0018] In any embodiment, the thickness of the release layer is 20nm~300nm, optionally 50nm~200nm, and the release layer is prepared from an aqueous release agent.
[0019] In any embodiment, the thickness of the flexible substrate is not less than 50 μm, and the flexible substrate includes at least one of polyethylene terephthalate, polycarbonate, polymethyl methacrylate, and polyimide.
[0020] In any embodiment, the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release layer is not less than 1000 nm.
[0021] Controlling the thickness of the embossing adhesive layer, catalyst layer, metal plating layer, and release layer within appropriate ranges helps to further ensure the smoothness of the soft mold surface and its mechanical properties, thereby ensuring the embossing effect.
[0022] The second aspect of this application provides the application of the soft mold provided in the first aspect in the field of nanoimprinting. Attached Figure Description
[0023] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a cross-sectional view of the soft mold of this utility model;
[0025] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;
[0026] Figure 3 This is a flowchart illustrating the preparation process of the soft mold of this utility model;
[0027] In the diagram: 1-Flexible substrate; 2-Imprint adhesive layer; 3-Catalyst layer; 4-Electroplated layer; 5-Mold release layer. Detailed Implementation
[0028] The following detailed description, with appropriate reference to the accompanying drawings, discloses an embodiment of a soft mold for nanoimprinting according to this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of providing a full understanding of this application by those skilled in the art and are not intended to limit the subject matter of the claims. Any product identical or similar to this application, derived by any person based on the teachings of this application or by combining features of this application with other prior art, falls within the protection scope of this application.
[0029] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are real numbers. Similarly, the numerical range "0-7" indicates that all real numbers between "0" and "7" have been listed in this document; "0-7" is simply a shortened representation of these numerical combinations. Furthermore, when describing an integer with a parameter ≥ 3, it is equivalent to disclosing that the parameter is, for example, an integer such as 3, 4, 5, 6, 7, 8, 9, 10, 11, etc.
[0030] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.
[0031] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.
[0032] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (1) and (2), indicating that the method may include steps (1) and (2) performed sequentially, or it may include steps (2) and (1) performed sequentially. For example, the mention that the method may also include step (3) indicates that step (3) may be added to the method in any order. For example, the method may include steps (1), (2) and (3), or it may include steps (1), (3) and (2), or it may include steps (3), (1) and (2), etc.
[0033] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.
[0034] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
[0035] like Figure 1 As shown, this application proposes a soft mold for nanoimprinting, wherein the soft mold comprises, in the thickness direction, the following:
[0036] Flexible substrate 1, which is made of a material that can transmit ultraviolet light;
[0037] An imprinting adhesive layer 2 is located on the surface of the flexible substrate 1. The imprinting adhesive layer 2 includes equally spaced parallel protrusions, and the thickness of the imprinting adhesive layer 2 is greater than the thickness of the protrusions.
[0038] Catalyst layer 3 is located on the surface of imprint adhesive layer 2 away from flexible substrate 1;
[0039] The metal coating 4 is located on the surface of the catalyst layer 3 away from the flexible substrate 1, and the thickness of the metal coating 3 is greater than the thickness of the catalyst layer 4.
[0040] The release layer 5 is located on the surface of the metal plating layer 4 away from the flexible substrate 1, and the thickness of the release layer 5 is less than the thickness of the metal plating layer 4.
[0041] The combined thickness of the catalyst layer 3, the metal plating layer 4, and the release layer 5 shall not be less than 500 nm.
[0042] Research has found that sequentially setting a catalyst layer, a metal plating layer, and a release agent layer on the imprinting adhesive layer, while controlling the sum of the thicknesses of the catalyst layer, metal plating layer, and release agent layer to be no less than 500 nm, can not only effectively prevent the reaction between the imprinting adhesive layer and the UV-cured material being imprinted during nanoimprinting, thus avoiding imprinting process failure, but also ensure the smoothness of the soft mold surface by setting the metal plating layer and controlling its thickness to be greater than the thickness of the release agent layer. This reduces the scrap rate caused by surface defects in the imprinted structure, ensuring the imprinting effect. More importantly, the metal plating layer can significantly improve the interface strength, thereby improving the mechanical properties of the soft mold and increasing its service life.
[0043] In addition, controlling the thickness of the imprinting adhesive layer to be greater than the thickness of the protrusions ensures that the groove between any two protrusions in the imprinting adhesive layer does not penetrate the imprinting adhesive layer, maintaining overall contact between the imprinting adhesive layer and the flexible substrate. This helps to improve the adhesion between the overall imprinting adhesive layer and the flexible substrate and reduces the risk of damage to the soft mold during the nanoimprinting process.
[0044] like Figure 2 As shown, in some embodiments, the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release layer is not less than 500 nm, i.e., H3+H4+H5≥500 nm. In some embodiments, the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release layer can be selected as 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, 1050 nm, 1100 nm, 1150 nm, 1200 nm, 1250 nm, 1300 nm, 1350 nm, 1400 nm, 1450 nm, 1500 nm, 1550 nm, 1600 nm, or a value within a range consisting of any two of the above values.
[0045] Controlling the sum of the thicknesses of the catalyst layer, metal plating layer, and release layer to be no less than 500 nm can not only effectively prevent the reaction between the imprinting adhesive layer and the UV-cured material being imprinted during the nanoimprinting process, thus avoiding the failure of the imprinting process, but also further ensure the smoothness of the soft mold surface and improve the mechanical properties of the soft mold.
[0046] like Figure 2 As shown, in some embodiments, the thickness H21 of the imprinting adhesive layer is 5 nm to 30 μm. In some embodiments, the thickness H21 of the imprinting adhesive layer can be selected as 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 400 nm, 500 nm, 600 nm, 800 nm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or a value within the range of any two of the above values.
[0047] The thickness of the imprinting adhesive layer can be controlled from 5nm to 30μm to meet the process requirements of different imprinting sizes.
[0048] In some embodiments, the imprinting adhesive layer is prepared from a photocurable imprinting adhesive.
[0049] In some embodiments, the photocurable imprinting adhesive includes at least one of acrylate compounds, epoxy compounds, and polyurethane compounds.
[0050] Acrylic, epoxy, or polyurethane compounds exhibit better curing performance than traditional fluorinated resins, which is beneficial for further improving the mechanical properties of soft molds.
[0051] like Figure 2 As shown, in some embodiments, the thickness H3 of the catalyst layer is 100 nm to 500 nm. In some embodiments, the thickness H3 of the catalyst layer can be selected as 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or a value within the range of any two of the above values.
[0052] Controlling the thickness of the catalyst layer within a suitable range not only provides a certain mechanical strength, but more importantly, it helps to provide sufficient reactive sites to facilitate the subsequent preparation of metal coatings, thereby significantly improving the mechanical properties of the soft mold.
[0053] In some embodiments, the porosity of the catalyst layer is less than 10%. In some embodiments, the porosity of the catalyst layer may be selected as 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a value within a range consisting of any two of the above values.
[0054] Controlling the porosity of the catalyst layer to below 10% can provide enough reactive sites for the preparation of the metal coating, while avoiding adverse effects caused by the contact between the metal coating and the imprint adhesive layer.
[0055] like Figure 2 As shown, in some embodiments, the thickness H4 of the metal coating is 300 nm to 800 nm. In some embodiments, the thickness H4 of the metal coating is 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, or a value within a range consisting of any two of the above values.
[0056] Controlling the thickness of the metal coating to 300nm~800nm can significantly improve the mechanical properties of soft molds.
[0057] In some embodiments, the metal plating includes at least one selected from gold, silver, and copper. In some embodiments, the metal plating includes gold. In some embodiments, the metal plating includes silver. In some embodiments, the metal plating includes copper.
[0058] Gold, silver, and copper all have a certain degree of strength, which can improve the interfacial strength and thus enhance the mechanical properties of soft molds.
[0059] like Figure 2As shown, in some embodiments, the thickness H22 of the protrusion is 1nm to 25nm, and the width W1 is 1nm to 10nm. In some embodiments, the thickness H22 of the protrusion can be selected as 1nm, 2nm, 4nm, 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, or a value within the range of any two of the above values, and the width W1 can be selected as 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, or a value within the range of any two of the above values.
[0060] Controlling the thickness and width of the protrusions within a suitable range can meet the requirements of different embossing processes and ensure the adhesion between the embossed adhesive layer and the flexible substrate.
[0061] like Figure 2 As shown, in some embodiments, the thickness H5 of the release layer is 20nm to 300nm. In some embodiments, the thickness H5 of the release layer can be selected as 20nm, 40nm, 50nm, 60nm, 80nm, 100nm, 120nm, 140nm, 150nm, 160nm, 180nm, 200nm, 220nm, 240nm, 250nm, 260nm, 280nm, 300nm, or a value within the range formed by any two of the above values.
[0062] Controlling the thickness of the release layer to no more than 300nm can ensure the overall improvement of the mechanical properties of the soft mold by the catalyst layer, metal coating, and release layer, while avoiding the impact of excessive release layer thickness on the surface smoothness of the soft mold.
[0063] In some implementations, the release layer is made from an aqueous release agent.
[0064] In some embodiments, the aqueous release agent includes at least one of polydimethylsiloxane, amino silicone oil, polyethylene wax, oxidized polyethylene wax, perfluoropolyether, polyacrylate, and polyvinyl alcohol.
[0065] Fluorinated resins are often used as imprinting layers for soft molds due to their low surface energy, facilitating the removal of the soft mold from the imprinted structure during the imprinting process. However, imprinting layers made of fluorinated resins have poor mechanical properties and are not environmentally safe. In this application, the imprinting layer is made of acrylic resin, epoxy resin, or polyurethane resin, and a water-based release agent is selected to prepare the release layer. This avoids the use of fluorinated substances and facilitates the removal of the soft mold during the imprinting process, which is beneficial to environmental protection.
[0066] like Figure 2As shown, in some embodiments, the thickness H1 of the flexible substrate is not less than 50 μm. In some embodiments, the thickness H1 of the flexible substrate can be selected as 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, or a value within a range consisting of any two of the above values.
[0067] In some embodiments, the flexible substrate includes at least one of polyethylene terephthalate, polycarbonate, polymethyl methacrylate, and polyimide.
[0068] like Figure 2 As shown, in some embodiments, the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release layer is not less than 1000 nm, i.e., H3+H4+H5≥1000 nm. In some embodiments, the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release layer can be selected as 1000 nm, 1050 nm, 1100 nm, 1150 nm, 1200 nm, 1250 nm, 1300 nm, 1350 nm, 1400 nm, 1450 nm, 1500 nm, 1550 nm, 1600 nm, or a value within a range consisting of any two of the above values.
[0069] like Figure 3 As shown in the figure, this application provides a method for preparing a soft mold, including:
[0070] S1, providing a flexible substrate 1;
[0071] S2, spin-coating photocurable embossing adhesive onto a flexible substrate;
[0072] S3, a master mold for nanoimprinting is placed on one side of the flexible substrate 1 coated with photocurable imprinting adhesive and imprinted. The master mold does not contact the flexible substrate. The photocurable imprinting adhesive is UV cured at room temperature.
[0073] S4, then remove the master mold to obtain the imprinting adhesive layer 2;
[0074] S5, Spray nano-palladium catalyst onto the surface of the imprinted adhesive layer 2 away from the flexible substrate to obtain catalyst layer 3;
[0075] S6, the above structure is then placed in a chemical plating solution to obtain a dense metal plating layer 4 on the surface of the catalyst layer 3 away from the flexible substrate. The chemical plating solution includes at least one of a chemical copper plating solution, a chemical gold plating solution, and a chemical silver plating solution.
[0076] S7. Spray a layer of water-based release agent onto the surface of the metal coating 4 away from the flexible substrate to obtain a soft mold.
[0077] In this article, the term "master mold" refers to a mold structure with a grating pattern.
[0078] In this paper, the spin coating process relies on the centrifugal force and gravity generated when the flexible substrate 1 rotates to fully distribute the photocurable imprinting adhesive onto the surface of the flexible substrate 1, forming a uniform imprinting adhesive layer 2. By controlling parameters such as the rotation speed, the thickness and uniformity of the imprinting adhesive layer 2 can be precisely controlled.
[0079] In step S3, the master mold does not directly contact the flexible substrate. That is, the groove between any two protrusions in the imprinting adhesive layer in the soft mold does not penetrate the imprinting adhesive layer. This helps to improve the adhesion between the imprinting adhesive layer and the flexible substrate and reduces the risk of the soft mold being damaged during the imprinting process.
[0080] It is understandable that sequentially setting a catalyst layer, a metal plating layer, and a release agent layer on the imprinting adhesive layer, and controlling the sum of the thicknesses of the catalyst layer, the metal plating layer, and the release agent layer to be no less than 500 nm, can not only effectively prevent the reaction between the imprinting adhesive layer and the UV-cured material being imprinted during the nanoimprinting process, thus avoiding imprinting process failure, but also further ensure the flatness of the soft mold surface, reduce the scrap rate caused by surface defects, and ensure the imprinting effect. More importantly, the metal plating layer can significantly improve the interface strength, thereby improving the mechanical properties of the soft mold.
[0081] In addition, the preparation of metal coatings using chemical plating solutions with the aid of a catalyst layer has the advantages of low raw material costs, simple processes, and no need for heating, thus saving production costs.
[0082] This application proposes some embodiments of the application of soft molds in the field of nanoimprinting.
[0083] Finally, it should be noted that the specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A soft mold for nanoimprinting, characterized by, The soft mold comprises, in the thickness direction of the soft mold: a flexible substrate made of a material capable of passing ultraviolet rays; an imprint adhesive layer on the surface of the flexible substrate, the imprint adhesive layer comprising protrusions arranged in parallel at equal intervals, the thickness of the imprint adhesive layer being greater than the thickness of the protrusions; a catalyst layer on the surface of the imprint adhesive layer away from the flexible substrate; a metal plating layer on the surface of the catalyst layer away from the flexible substrate, the thickness of the metal plating layer being greater than the thickness of the catalyst layer; a release layer on the surface of the metal plating layer away from the flexible substrate, the thickness of the release layer being less than the thickness of the metal plating layer; wherein the sum of the thicknesses of the catalyst layer, the metal plating layer and the release layer is not less than 500 nm.
2. The soft mold according to claim 1, characterized by The thickness of the imprint adhesive layer is 5 nm to 30 μm, and the imprint adhesive layer is prepared from a photocurable imprint adhesive.
3. The soft mold according to claim 1, wherein The thickness of the catalyst layer is 100 nm to 500 nm, and the porosity of the catalyst layer is not higher than 10%.
4. The soft mold according to claim 1, characterized by The thickness of the metal plating layer is 300 nm to 800 nm, and the metal plating layer comprises at least one of gold, silver and copper.
5. The soft mold according to claim 1, wherein The thickness of the protrusions is 1 nm to 25 nm, and the width of the protrusions is 1 nm to 10 nm.
6. The soft mold according to any one of claims 1 to 5, wherein The thickness of the release layer is 20 nm to 300 nm, and the release layer is prepared from an aqueous release agent.
7. The soft mold according to any one of claims 1 to 5, wherein The thickness of the flexible substrate is not less than 50 μm, and the flexible substrate comprises at least one of polyethylene terephthalate, polycarbonate, polymethyl methacrylate and polyimide.
8. The soft mold according to any one of claims 1 to 5, wherein The sum of the thicknesses of the catalyst layer, the metal plating layer and the release layer is not less than 1000 nm.