A stamp for use in imprint lithography, a method for manufacturing the same, and a method for imprint lithography.

Abstract

A stamp in imprint lithography and a method for using the stamp. The stamp is configured to form a pattern on a photoresist layer, and comprises a transparent layer and a plurality of protrusions thereon for imprinting the pattern, wherein the plurality of protrusions are made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks passing light. The present invention also relates to a method for manufacturing the stamp.

Description

Technical Field

[0001] The present invention relates to a stamp device for use in imprint lithography. Further, the present invention relates to a method of performing (nano) imprint lithography. Further, the present invention relates to a method and system for manufacturing a stamp for use in imprint lithography. In addition, the present invention relates to an imprint lithography system. Also, the present invention relates to a roll-to-roll system comprising a stamp for performing (nano) imprint lithography. The present invention also relates to the use of a stamp in imprint lithography.

Background Art

[0002] Imprint lithography has come to be regarded as a promising high-resolution and cost-effective technique for transferring patterns onto various substrates. This technique involves using a stamp having a predetermined pattern, which, when brought into contact with a photoresist layer, transfers the pattern onto the photoresist. The pattern can be transferred to any curable polymer layer intended for imprinting. Thereafter, a curing process is performed on the polymer, and subsequently the stamp is removed. Generally, a high-quality pattern is achieved through the imprinting process. However, achieving a very high aspect ratio is difficult because the removal of the stamp becomes impossible due to the large contact area. Therefore, when dealing with high aspect ratio structures and / or non-planar substrates, the stamp may not always be able to produce a uniform and high-quality pattern.

[0003] Generally, it is difficult to obtain a thin film structure having a large aspect ratio form. However, such a structure can add or improve the function of a device. For example, such a structure can be used to realize a 3D battery, an optical collimator, a flexible ultrasonic system, etc.

[0004] High aspect ratio structures can be obtained, for example, by using UV photolithography with a special (negative-toned) photoresist. The aspect ratio is limited due to light scattering. Light scattering results in imperfect structures, particularly at the bottom of the structure: the entire photoresist is not removed by development. As a result, connections between imprinted structures may remain, for example, which is undesirable.

[0005] Another known method for achieving high aspect ratio structures is embossing. This involves deforming the coating (at high temperatures if necessary) using a physical stamp. While this is effective for some material combinations, it usually results in the formation of a structure (a so-called residual layer) on top of the continuous layer. This is inherent to embossing and is due to the fact that the material is not actually removed. To remove this residual layer, a reactive ion etching process is commonly applied, which can degrade (etch away or oxidize) the underlying layer.

[0006] There is a need for improved stamps that can preferably provide more uniform and / or high-quality patterns, even when dealing with high aspect ratio structures and / or non-planar substrates. It is desirable that the stamps can address the constraints arising from light scattering, which can result in imperfect structures and undesirable connections between imprinted configurations. Furthermore, there is a need for methods that can avoid the formation of residual layers, thereby avoiding the need to use harmful processes such as reactive ion etching to remove these residual layers. Such additional harmful processes can potentially degrade the underlying layers by etching or oxidizing the material. [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a method and system for avoiding at least one of the aforementioned drawbacks.

[0008] Additionally, or alternatively, an object of the present invention is to provide an improved design for a stamp for use in imprint lithography.

[0009] Additionally, or alternatively, an object of the present invention is to improve the manufacture of stamps for use in imprint lithography.

[0010] Additionally, or alternatively, an object of the present invention is to provide an improved imprint lithography system. [Means for solving the problem]

[0011] Furthermore, the present invention provides a stamp for use in imprint lithography, the stamp being configured to form a pattern on a photoresist layer, the stamp comprising a transparent layer and a plurality of protrusions thereon for imprinting the pattern, the plurality of protrusions being made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern.

[0012] Advantageously, the present invention provides an improved stamp design that is well suited to high aspect ratio imprint lithography (e.g., 3D imprint lithography). The light-absorbing properties of the protrusions allow for selective light shielding, thereby improving pattern transfer, especially when dealing with high aspect ratio structures and non-planar substrates. The flexibility allows for better avoidance of damage to the imprint structure. This stamp can be used in the manufacture of various systems and structures. For example, the stamp can be used in the manufacture of advanced microelectronics, optical components with complex patterns, and the like.

[0013] The stamps described herein offer the advantage of achieving uniform and high-quality patterns and effectively address the challenges associated with high aspect ratio structures and non-planar substrates. By effectively managing constraints caused by light scattering, the stamps ensure precise structures and eliminate undesirable connections between imprinted configurations. Furthermore, they better avoid the formation of structures on continuous residual layers, thereby eliminating the need for harmful processes such as reactive ion etching (RIE). This approach not only streamlines the process but also protects the underlying layers from potential degradation caused by etching or oxidation, thereby improving overall performance and reliability.

[0014] Optionally, the protrusions are adapted to allow for an increased aspect ratio in the pattern being transferred. This can result in improved fidelity of pattern transfer for high aspect ratio structures.

[0015] The stamp can be adapted to transfer the complex structure on its surface to another layer, ensuring precise replication of a given pattern onto a target photoresist layer.

[0016] Stamps usable in imprint lithography processes can be manufactured using a master or mold, which acts as a template for creating a predetermined pattern on the stamp's surface. This manufacturing approach offers several advantages. Firstly, the use of a master or mold allows for the precise replication of complex structures, ensuring that the stamp accurately reproduces the desired pattern on the target photoresist layer. Secondly, this manufacturing method allows for the production of multiple stamps with identical configurations, which can be crucial for large-scale manufacturing processes or applications requiring uniform patterning across numerous substrates. Thirdly, the use of a master or mold allows for the incorporation of various materials, including the aforementioned composite materials, into the stamp's structure, providing flexibility in optimizing the stamp's properties to meet the requirements of specific applications. Finally, the master or mold approach can be adapted to various manufacturing techniques such as casting, injection molding, and photolithography, thus offering compatibility with a wide range of manufacturing environments and technologies.

[0017] To create a stamp, the following steps may be performed: (1) a master is prepared; (2) a matrix containing a UV absorber (e.g., silicone containing black nanopowder) is used; (3) this mixture is applied to the master and then drawn out; (4) clear silicone is applied around it before the entire stamp is removed.

[0018] Optionally, multiple protrusions may consist of a material containing a polymer matrix embedded with a light-absorbing agent.

[0019] By incorporating light-absorbing agents into the polymer matrix, the stamp gains several advantages, including improved wear resistance, enhanced durability, and reduced degradation over time. This approach eliminates the need for a separate adhesive layer, which can wear out more quickly due to stamping, and is required for bonding to external components (e.g., metal plates). Furthermore, the incorporated light-absorbing agents allow for better control of the stamp's smoothness, which is essential for proper stamp removal and adhesion of the photoresist layer to the substrate. The combination of these elements ultimately results in a more sustainable and efficient stamping process.

[0020] An advantage is the absence of connection (e.g., adhesive) between the light-shielding material (e.g., hard metal plate) and the substrate. Smoothness can be significantly improved by incorporating a light-absorbing agent into the polymer matrix. Adhesion between the stamp and the stamped layer is determined by the specific surface area; a larger specific surface area makes stamp removal more difficult. Proper removal becomes more difficult if the stamp is rough, or becomes rough with use.

[0021] Using materials containing a polymer matrix embedded with light absorbers for the protrusions offers the advantage of improved flexibility and durability. The protrusions may be flexible instead of rigid. The material composition of the protrusions effectively blocks light during the exposure process, ensuring accurate pattern transfer.

[0022] Optionally, the light absorber is uniformly distributed within the polymer matrix.

[0023] The uniform distribution of light absorbers within the polymer matrix ensures consistent light absorption characteristics across the entire length of the stamp's protrusions. This uniformity leads to improved accuracy and reproducibility of pattern transfer.

[0024] For example, this feature would be particularly beneficial in the manufacture of high-precision sensors or MEMS devices.

[0025] Optionally, the light absorber is an ultraviolet (UV) absorber.

[0026] Incorporating an ultraviolet (UV) absorber into the material composition of the protrusions provides the advantage of precise control over the exposure process. This specificity of light absorption reduces the risk of unwanted exposure, which leads to higher-quality patterns.

[0027] Optionally, the light absorber includes a powder.

[0028] Including a powder such as fine particles as the light absorber in the protrusions contributes to an improvement in the light-blocking ability. This improvement ensures better pattern transfer fidelity and uniformity.

[0029] For example, this feature can be advantageous for the manufacture of nanostructured solar cells where precise patterning is essential for optimal performance. Various other applications can benefit from this advantageous embodiment.

[0030] Optionally, the (average) particle size is less than 5 nanometers to facilitate smooth coating and create small structures on the stamp. When the particles are mixed with the matrix material, the particles may tend to aggregate into lumps. To prevent this, a dispersant can be added during the mixing process.

[0031] Optionally, the powder includes carbon powder, preferably black carbon nanopowder.

[0032] Using fine powdered carbon powder can be important, especially for small dimensions, to avoid the roughness of the stamp. Roughness generates more resistance and may prevent the removal of the stamp.

[0033] Using black carbon nanopowder as the light absorber further improves the light-blocking efficiency of the protrusions. This improvement enables even more accurate pattern transfer, especially for high aspect ratio structures. A higher aspect ratio improves the collimation effect. The angular distribution depends on the aspect ratio. The flexibility of the silicone used for the UV-absorbing protrusions can be selected based on the shape and size of the structure.

[0034] In some examples, the aspect ratio is greater than 5, preferably greater than 8, and more preferably greater than 10.

[0035] Black carbon nanopowder exhibits excellent light absorption properties, which contribute to improved light shielding efficiency of the protrusions. This improved light shielding capability ensures more accurate and reliable pattern transfer, especially for high aspect ratio structures.

[0036] Furthermore, the black carbon nanopowder has a large surface area, which allows for strong interaction with the polymer matrix, resulting in improved mechanical properties of the composite material. The enhanced durability and toughness of these protrusions ensure consistent pattern transfer, even under repeated use or harsh processing conditions.

[0037] Furthermore, the incorporation of black carbon nanopowder enables highly tunable absorption spectra, allowing for the customization of stamps for specific applications or wavelengths. This tunability is advantageous for the manufacture of wavelength-specific components or devices, such as dedicated filters or photodetectors.

[0038] Furthermore, using black carbon nanopowder in composite materials is cost-effective and environmentally friendly because carbon-based materials are abundant and readily available. This advantage contributes to the overall sustainability and affordability of the stamp, making it an attractive option for various industries and applications.

[0039] In some cases, powders such as carbon black (e.g., nanopowder) are dispersed within the silicone, allowing for easy concentration adjustment. In some cases, black carbon nanopowder is added to the silicone to construct a stamp with two parts: a transparent part and a more flexible part containing black carbon powder that can absorb ultraviolet light. Other powders or dyes may also be used, as long as they absorb ultraviolet light. The substrate may be any material that is flexible and elastic and does not break when deformed.

[0040] Optionally, light absorbers may include dyes.

[0041] By incorporating dyes as light absorbers into the protrusions, tuned absorption at specific wavelengths becomes possible, enabling customized pattern transfer capabilities. Dyes allow for easy customization of stamps for specific applications or wavelengths. This adaptability is advantageous for the manufacture of devices or components with specific spectral requirements, such as wavelength-selective filters, sensors, and photonic devices. Dyes can offer a wide range of light absorption properties, which can be easily tuned by selecting different dye types or adjusting the dye concentration within the polymer matrix. This tunability allows for precise control over the stamp's light absorption properties, ensuring accurate and reliable pattern transfer in a variety of imprint lithography processes.

[0042] Furthermore, dyes can be selected based on their compatibility with the polymer matrix, resulting in improved mechanical properties of the composite material. This improved protrusion durability ensures consistent pattern transfer performance, even under harsh processing conditions or repeated use.

[0043] In some cases, both powder and dye are used. This can further improve the properties of the protrusions.

[0044] It will be understood that, additionally or alternatively, other materials may be used instead of powder materials or dyes to form composite materials with UV-absorbing properties.

[0045] Optionally, the light absorber includes at least one of the following materials having UV absorption properties: nanoparticles, metal-organic frameworks (MOFs), conductive polymers, organic-inorganic hybrid materials, liquid crystals, and inorganic-organic hybrid nanoparticles.

[0046] In this way, the range of light absorption capabilities can be extended. This versatility allows the stamp to be used in a wide range of applications.

[0047] Optionally, the Young's modulus of the composite material is less than 20 GPA, more preferably less than 10 GPA, and even more preferably less than 5 GPA. In some examples, the Young's modulus of the composite material is in the range of 0.01 to 10 GPA, preferably in the range of 0.05 to 5 GPA.

[0048] Optionally, the polymer matrix may be a silicone material such as polydimethylsiloxane (PDMS).

[0049] Using silicone materials such as polydimethylsiloxane (PDMS) in polymer matrices offers advantages such as improved flexibility, durability, and compatibility with various substrates. These properties ensure uniform pattern transfer even on uneven or non-planar surfaces.

[0050] Optionally, the transparent material consists of a polymer matrix material.

[0051] By constructing the transparent layer from the same polymer matrix material as the protrusions, compatibility between materials is ensured, reducing the risk of delamination or deformation. This consistency contributes to improved reliability and lifespan of pattern transfer. For example, this feature would be beneficial in the manufacture of long-life microfluidic devices or lab-on-a-chip systems.

[0052] The use of polymer matrix materials in the transparent layer offers excellent compatibility with the composite material of the protrusions. This compatibility results in a strong bond between the transparent layer and the protrusions, ensuring consistent and precise pattern transfer during the imprint lithography process. Furthermore, it provides good transmittance over a wide wavelength range. This property enables versatile use of the stamp in various applications, including those requiring different exposure wavelengths such as ultraviolet (UV) and visible light. This broad transmittance range ensures accurate and efficient transmission of light through the transparent layer during exposure, contributing to improved patterning results.

[0053] Furthermore, polymer matrix materials often possess superior mechanical properties such as flexibility and toughness. These properties allow stamps to conform more effectively to non-planar or textured substrates than rigid materials, improving pattern transfer quality on non-planar surfaces. This advantage is particularly beneficial for applications requiring high-resolution patterning on curved, flexible, or textured substrates, such as flexible electronics, sensors, and displays.

[0054] Furthermore, polymer matrix materials are typically lightweight and easy to process, contributing to the overall ease of stamp manufacturing and handling. This advantage can lead to cost reductions and improved throughput in the production environment, making stamps an attractive option for various industries requiring high-quality patterning capabilities.

[0055] Optionally, the transparent layer is made of a first material having a first rigidity, and the multiple materials are made of a second material having a second rigidity, where the first rigidity is higher than the second rigidity.

[0056] By designing a transparent layer with higher rigidity than flexible protrusions, better control over the imprinting process is possible, ensuring uniform pressure distribution and improved pattern transfer accuracy. This advantage is particularly useful in applications where precise pattern alignment is critical, such as the fabrication of multilayer microelectronic devices.

[0057] Optionally, the photoresist layer is a photocurable polymer.

[0058] Photoresists are photosensitive materials that undergo a chemical change when exposed to light, which explains their usefulness in various photolithography and microfabrication processes. Photoresists can be classified into two main categories: positive photoresists and negative photoresists. Photocurable polymers (also known as photopolymers or UV-curable polymers) are materials that solidify or harden when exposed to ultraviolet (UV) light or other forms of radiation. These polymers are frequently used as photoresists in photolithography processes because they provide precise patterning and good resolution. In the case of negative photoresists, the exposed areas of the photoresist become crosslinked and insoluble in the developer, while the unexposed areas remain soluble and can be removed. This property makes negative photoresists suitable as photocurable polymers. Some common examples of negative photoresists include the widely used epoxy photoresist SU-8 and DNQ novolac resin. On the other hand, positive photoresists become more soluble in developer when exposed to light. Although positive photoresists do not function as photocurable polymers in the same way as negative photoresists, they still play an important role in photolithography and microfabrication processes.

[0059] According to one embodiment, the present invention provides a method for performing (nano)imprint lithography, the method comprising: preparing a stamp configured to form a pattern on a photoresist layer, the stamp comprising a transparent layer and a plurality of protrusions extending from the transparent layer, the protrusions configured to imprint the pattern on the photoresist layer, the plurality of protrusions being a light-shielding pattern, and being made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern; contacting the stamp with the photoresist layer such that the plurality of protrusions imprint the pattern on the photoresist layer; exposing the photoresist layer to light through the transparent layer, the light passing through the transparent layer and being selectively blocked by the light-shielding pattern formed by the plurality of protrusions, thereby inducing a selective reaction in the exposed region of the photoresist layer; and developing the photoresist layer to remove regions that have not been selectively reacted, thereby forming a desired pattern on a substrate.

[0060] The stamps described herein effectively address the challenge of manufacturing thin-film structures with high anisotropy, thereby enabling improved functionality across a variety of applications, including 3D batteries, optical collimators, and flexible ultrasonic devices. By providing a reliable and efficient solution, the stamps not only facilitate the creation of high-quality, high-aspect-ratio patterns but also minimize adverse effects on underlying layers.

[0061] The stamp, with its dark structure embedded in the protrusions, prevents the residual layer beneath this structure from receiving light (e.g., UV light), allowing this residual layer to be washed away and eliminating the need for additional etching steps. While a wet rinsing step is sufficient, dry etching in a vacuum system can be expensive and slow and may affect the structure. Advantageously, this method can be used with less wear compared to conventional methods, making it highly suitable for roll-to-roll processes. Furthermore, light scattering can be effectively avoided. The stamp can capture scattered light, resulting in a collimating effect and enabling the creation of structures with much higher aspect ratios.

[0062] Silicone simplifies the manufacturing process by trapping air and allowing it to escape when a vacuum is applied. In some cases, carbon powder is used as a UV absorber. For some applications, carbon powder can be more durable and longer-lasting than dyes.

[0063] The use of metallic materials in stamps can hinder their removal. The stamps according to this disclosure may have a desired degree of flexibility. For example, UV-absorbing powders, nanoparticles, dyes, etc., can be mixed with a silicone material to create a flexible compound.

[0064] In some examples, the multiple protrusions consist of a material containing a polymer matrix embedded with a light-absorbing agent.

[0065] Improved durability can be achieved by incorporating chemicals into the material itself (e.g., embedding carbon powder, particles, dyes, and / or any other light-blocking / light-absorbing agents). During the process, the chemicals are not simply present on the surface, but rather are incorporated into the silicone. As a result, the chemicals are located within the material, leading to reduced wear.

[0066] Optionally, a roll-to-roll imprinting system may be used, which includes a first roller on which the transparent layer and the stamp having the plurality of protrusions are mounted; a second roller on which the photoresist layer is mounted, the photoresist layer being provided on a flexible substrate; a light source for applying UV irradiation; and a mechanism for advancing the flexible substrate having the photoresist layer between the first and second rollers. The method includes the steps of: rotating the first roller and the second roller so that the transparent layer and the stamp having the plurality of protrusions contact the photoresist layer on the flexible substrate, thereby imprinting the pattern onto the photoresist layer during a roll-to-roll process; and maintaining pressure between the first roller and the second roller during the roll-to-roll process to ensure that the pattern is uniformly imprinted onto the photoresist layer, wherein the light source is configured to provide UV irradiation during and / or after imprinting.

[0067] Using a roll-to-roll imprinting system in this method offers the advantage of continuous, high-throughput production. This system ensures uniform pattern imprinting onto the photoresist layer during the roll-to-roll process, making it ideal for large-scale manufacturing of flexible electronics, solar cells, and advanced optical components.

[0068] The roll-to-roll process can present challenges, particularly with high aspect ratio structures, and can potentially damage the stamp. Ensuring that the stamp's protrusions have some degree of flexibility can be crucial to avoiding damage during the process, especially with high aspect ratio structures. Therefore, according to the present invention, potential damage can be better prevented.

[0069] Optionally, a light source is provided inside the first roller to apply light / radiation (e.g., UV) in situ during imprinting, and the first roller is at least partially transparent to light / radiation.

[0070] The light source can be placed inside a transparent drum, allowing in-situ crosslinking while applying pressure during the imprint process. Alternatively, the exposure process can be performed adjacent to the drum after the imprint process is complete and no pressure is applied. Following light (e.g., UV) crosslinking, unexposed areas, unreacted areas, and any residual layers can be removed through washing or development, a process not possible in conventional imprint methods. Traditionally, residual layers had to be removed using a plasma etcher, which was not well-suited to roll-to-roll processes.

[0071] According to one embodiment, the present invention provides a method for manufacturing a stamp for use in imprint lithography, the method comprising the steps of: forming a flexible composite material having light-absorbing properties, wherein the flexible composite material comprises a material including a polymer matrix in which a light-absorbing agent is embedded; and forming a plurality of protrusions on a transparent layer, wherein the plurality of protrusions are configured to imprint a pattern, and the plurality of protrusions form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern.

[0072] The stamp manufacturing method involves forming a flexible composite material with light-absorbing properties and creating protrusions on a transparent layer, offering the advantage of a consistent and reliable stamp manufacturing process. This method ensures a uniform light-shielding pattern and high-quality pattern transfer capability of the stamp, making it suitable for applications in microelectronics, nanotechnology, and optoelectronics.

[0073] Optionally, the composition of the material is selected to have a predetermined target stiffness, which is determined based on the dimensions and / or geometric shape of the projection.

[0074] The method of selecting the material composition based on a predetermined target stiffness, taking into account the dimensions and / or geometric shape of the protrusions, ensures the optimal performance of the stamp. This adjusted approach contributes to improved pattern transfer accuracy and reproducibility, which is advantageous for applications requiring high-precision patterning.

[0075] According to one aspect, the present invention provides a system comprising a stamp according to the present disclosure, the system configured to perform imprint lithography.

[0076] It will be understood that any aspect, feature, and option described in reference to the device (e.g., stamp) and system also applies equally to the method and the described use. It is also clear that one or more of the above aspects, features, and options may be combined. [Brief explanation of the drawing]

[0077] The present invention will be further illustrated based on exemplary embodiments shown in the drawings. These exemplary embodiments are shown as non-limiting examples. The drawings are merely schematic representations of embodiments of the present invention shown as non-limiting examples.

[0078] [Figure 1A] Figure 1a shows a schematic diagram of an embodiment of the stamp. [Figure 1B] Figure 1b shows a schematic diagram of an embodiment of the stamp. [Figure 2A] Figure 2a shows a schematic diagram of an embodiment of the stamp. [Figure 2B] Figure 2b shows a schematic diagram of an embodiment of the stamp. [Figure 3] Figure 3 shows a schematic diagram of an embodiment of the method. [Figure 4A] Figure 4a shows the experimental results. [Figure 4B] Figure 4b shows the experimental results. [Figure 5] Figure 5 shows an example image of a stamp. [Figure 6A] Figure 6a shows an example image of the imprint. [Figure 6B] Figure 6b shows an exemplary image of the imprint. [Figure 7] Figure 7 shows a schematic diagram of the method. [Figure 8] Figure 8 shows a schematic diagram of the graph. [Figure 9] Figure 9 shows a schematic diagram of the roll-to-roll system. [Modes for carrying out the invention]

[0079] Figures 1a and 1b show schematic diagrams of an embodiment of stamp 1 for use in imprint lithography. Stamp 1 is configured to form a pattern on a photoresist layer and comprises a transparent layer 3 and a plurality of protrusions 5 thereon for imprinting the pattern. The plurality of protrusions 5 are a light-shielding pattern and are made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern. In this embodiment, the protrusions 5 extend outward from a flat surface. However, various other embodiments are possible. For example, the protrusions 5 may extend at least partially into the transparent layer.

[0080] In the example shown in Figure 1b, the protrusions 5 are elongated, resulting in a high aspect ratio. This leads to improved pattern transfer because light is more collimated in the space 7 between the protrusions.

[0081] Figures 2a and 2b show schematic diagrams of embodiments of stamp 1. In the example shown in Figure 2a, the projection 5 extends from a region containing a recess in the transparent layer 3. In the example shown in Figure 2b, the projection extends deep into the transparent layer 3. In some examples, the projection may be provided in a through hole located within the transparent layer 3.

[0082] Figure 3 shows a schematic diagram of an embodiment of an exemplary method 100 for performing imprint lithography. Advantageously, the stamp can be used for imprints without residual layer. The method shown in Figure 3 (a cross-sectional side view is shown) may include the following steps:

[0083] A first step 101 of the present disclosure provides a stamp having an optically transparent 3D structure and an opaque 3D structure. The stamp 1 may be, for example, a PDMS carbon stamp. An open space 7 is provided between the protrusions 5.

[0084] A second step 102 involves embossing / imprinting a negative tone photoresist 11, such as SU-8, onto the surface using a stamp 1.

[0085] A third step 103 involves applying flood exposure L to the entire surface, allowing the opaque 3D structure of the stamp to function as an internal photomask, effectively preventing light from reaching the underlying photoresist 11. UV light may be used for UV crosslinking of the negative-type resist through the partially black stamp 1 located at the protrusions 5. Unexposed resist can be removed by development.

[0086] A fourth step 104 involves removing the stamp to expose the unexposed portion of the photoresist. The stamp can then be peeled off.

[0087] A fifth step 105 involves removing unexposed photoresist regions using an appropriate developer to ultimately achieve a patterned surface with no residual layer whatsoever. This allows the unexposed resist to be developed.

[0088] This approach demonstrates the versatility and precision of combined-nanoimprint-and-photolithography (CNP) technology, which fuses the advantages of both nanoimprint lithography (NIL) and photolithography.

[0089] Imprint lithography technology combines the advantages of nanoimprint lithography (NIL) and photolithography, resulting in a combined nanoimprint and photolithography patterning method. In combined nanoimprint and photolithography (CNP), a hybrid mask-mold can be used. This mask-mold consists of a UV-transparent material and features a light-shielding metal layer positioned above the mold's protrusions. This innovative design allows for more precise and efficient patterning while avoiding the use of a sacrificial layer.

[0090] In flood exposure processes, the collimated beam can be crucial for optimal results. A thick layer that effectively absorbs non-collimated light may be used, effectively integrating the built-in collimator function into the stamp design. This innovative configuration improves the performance of the imprinting process by ensuring that only collimated light interacts with the photoresist during flood exposure, leading to more precise and uniform patterning.

[0091] Figures 4a and 4b show experimental results obtained using a scanning electron microscope (SEM) and illustrate imprint structures obtained using the stamps according to this disclosure. Stamp 1 is used to form patterns on a surface without requiring a sacrificial layer, which is achieved through a specific stamp design. In this example, the stamp used has a continuous, optically transparent base on which an opaque ("black") 3D structure is superimposed. These opaque structures are formed by dispersing carbon black particles within a polydimethylsiloxane (PDMS) matrix, although alternative methods that absorb ultraviolet (UV) light may also be used.

[0092] UV-absorbing particles or dyes can be injected into a portion of the stamp material, i.e., at least the protrusions. The UV-absorbing component can be designed as a 3D structure rather than a conventional 2D layer. Advantages include improved stamp durability. The stamp's lifespan is significantly longer compared to technologies using metal layers, as metal layers can be damaged over time. Furthermore, improved light management can be achieved. The 3D light-absorbing structure effectively removes scattered UV light, enabling the formation of structures with higher aspect ratios. The imprinted portion of the stamp also functions as a collimator, further contributing to process precision. Additionally, material customization is enabled. The imprinted portion of the stamp can be made of a different material than the carrier portion, allowing for adjustment of elasticity based on specific requirements. These improvements make new stamp designs more versatile and efficient, resulting in improved performance and lifespan.

[0093] Figure 4a shows a SEM image of a conventional imprint with a residual layer. The structure may be observed to show signs of damage. Figure 4b shows a SEM image of an imprint without a residual layer, obtained by performing the method according to this disclosure.

[0094] When the underlying layer is sensitive to oxidation, it is especially important to avoid the reactive ion etching (RIE) process, as the RIE process can cause damage or impair the material's properties.

[0095] According to this disclosure, the light-absorbing configuration (see projection 5) can be manufactured without contaminating the surrounding area with absorbing material, ensuring clean and precise imprinting. Furthermore, stable dispersion or dissolution of nanoparticles or dyes in the stamp's matrix material (e.g., carbon nanopowder in a silicone matrix) can be achieved, resulting in a uniform dark area that effectively absorbs light. As a result, improved performance and accuracy can be obtained, making the stamp advantageous for various applications in imprinting and lithography.

[0096] Figure 5a shows an exemplary image of the stamp obtained using SEM. Figure 5a shows a two-layer stamp 1 having a black hexagonal structure with a width of 40 μm and a height of 40 μm.

[0097] Figures 6a and 6b show exemplary images of imprints obtained using the exemplary stamp shown in Figure 5a. These images were also acquired using SEM. These experiments demonstrate the effectiveness of the black stamp design during imprinting with photoresist (SU-8 in this experiment). After additional flood exposure and subsequent development steps, the residual layer is completely removed. These results demonstrate the excellent performance of the stamp design in achieving clean and precise imprints with no residual layer whatsoever. Figure 6b shows an enlarged SEM image.

[0098] Figure 7 shows a schematic diagram of a method 200 for manufacturing a stamp 1 according to the present disclosure. In the first step 201, a master having an exemplary SU-8 patterned, for example by lithography, is provided. The master may be covered with a primer. In the second step 202, a thin “black” silicone layer may be blade-coated, through which air may escape. In the third step 203, air is released from the constituent pockets using a vacuum. In the fourth step 204, a scraping step is performed to scrape off any residue. In the fifth step 205, the silicone is crosslinked. In the sixth step 206, a fully transparent layer (e.g., PDMS) is provided. In the seventh step 207, the stamp is released.

[0099] Figure 8 shows a schematic graph representing the elastic modulus (E-modulus) of an exemplary polydimethylsiloxane (PDMS), a type of silicone. A typical mixing ratio of PDMS is 1:10, which results in an E-modulus of 2.5 MPa. Using different mixing ratios can yield lower E-modulus values, thereby allowing for control of flexibility. Therefore, this can be used to adjust material properties according to the specific requirements of the application in which the stamp will be used. In some examples, the material composition is selected to have a predetermined target stiffness, which is determined based on the dimensions and / or geometric shape of the protrusion.

[0100] Figure 9 shows a schematic diagram of a roll-to-roll imprint lithography system 30. The roll-to-roll imprint lithography system 30 includes a first roller 31 to which a stamp 1 is attached, the stamp 1 comprising a transparent layer and a plurality of protrusions extending from the transparent layer, the protrusions configured to imprint a pattern onto a photoresist layer, and a light-shielding pattern made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern, a second roller 33 having a flexible substrate to which a photoresist layer 35 is attached, and an imprint process The system comprises a third roller 37 configured to receive and support a flexible substrate having a patterned photoresist layer 39 after rolling; a light source configured to emit radiation (e.g., UV light); a mechanism for advancing the flexible substrate 35 having the photoresist layer between the first roller 31, the second roller 35, and the third roller 39; and a pressure control system that maintains the pressure between the first roller 31 and the second roller 33 during the roll-to-roll process to ensure uniform imprinting of the pattern onto the photoresist layer.

[0101] During operation, the first roller 31 and the second roller 33 may rotate so that the stamp 1, having the transparent layer and the plurality of protrusions 5, contacts the photoresist layer on the flexible substrate, imprinting the pattern onto the photoresist layer during a roll-to-roll process. A light source may be configured to provide radiation during and / or after the imprinting process, selectively reacting the exposed areas of the photoresist layer by passing through the transparent layer and being selectively blocked by the light-shielding pattern formed by the plurality of protrusions. A subsequent developing process may be used to remove selectively unreacted areas of the photoresist layer, thereby forming a desired photoresist pattern on the flexible substrate, which is subsequently transferred for further processing and / or collection.

[0102] In this embodiment, advantageously, the light source 50 is provided inside the first roller 31 to apply radiation (e.g., UV light) in situ during imprinting, and the first roller 31 is at least partially transparent to the radiation. Thus, the first roller 31 can form a transparent drum with the light source located inside. The light source 50 may be, for example, a UV lamp. The outer surface of the first roller 31 may include a patterned structure of the stamp 1.

[0103] The photoresist layer may be an uncured polymer. In some examples, copper foil is used to support the resin layer. In some examples, the resin layer may be coated onto a substrate such as copper foil. The adhesion of the resin layer to the copper foil must be stronger than the adhesion of the stamp to the resin layer; otherwise, the resin layer will peel off the copper foil instead of the stamp peeling off the resin layer. Easier stamp removal allows for a wider range of substrate choices. Silicone adheres well to silicone, but metal foils exhibit inferior adhesion.

[0104] Advantageously, the stamps relating to this disclosure can be effectively used in roll-to-roll processes, enabling scalability across various industrial manufacturing processes.

[0105] Following carbon powders such as black carbon nanopowder and graphene oxide powder, it will be understood that various other powders can be used for UV light absorption. Examples include titanium dioxide (TiO2), zinc oxide (ZnO), cerium oxide (CeO2), iron oxide (Fe2O3), barium sulfate (BaSO4), tantalum pentoxide (Ta2O5), niobium pentoxide (Nb2O5), manganese dioxide (MnO2), copper oxide (CuO), silica nanoparticles (SiO2), zirconium dioxide (ZrO2), and europium (Eu)-doped yttrium vanadate (YVO4). Various other powders can be used.

[0106] It will be understood that various dyes with UV absorption properties can be used. Examples include perylene dyes, anthraquinone dyes, metalloporphyrin dyes, phthalocyanine dyes, cyanine dyes, rhodamine dyes, azo dyes, indoline dyes, squalane dyes, merocyanine dyes, xanthene dyes, diketopyrrolopyrrole (DPP) dyes, thiazine dyes, naphthol dyes, acridine dyes, hemicyanine dyes, and triphenylmethane dyes. Various other dyes can also be used.

[0107] The above illustrative list is not exhaustive, and numerous other powder materials or dyes with UV absorption properties may exist. The effectiveness of these materials may depend on factors such as particle size, concentration, and the specific application in which they are used.

[0108] It will be understood that silicone materials can be considered as flexible polymer matrices. Silicones are a type of synthetic polymer composed of silicon, oxygen, carbon, and hydrogen atoms. Depending on their chemical structure and formulation, they possess a variety of properties, including flexibility. One common type of silicone material often used as a flexible polymer matrix is ​​polydimethylsiloxane (PDMS).

[0109] Several flexible polymer matrices can be used to create composite materials with UV absorption properties. Examples include polyurethane (PU), polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU), polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), polyethylene (PE), styrene-butadiene rubber (SBR), polypropylene (PP), polystyrene-ethylene-butylene-styrene (SEBS), and elastomer polyesters. These flexible polymer matrices, when combined with UV-absorbing materials, can form composite materials that exhibit UV blocking properties while maintaining flexibility. Various other polymer matrices can also be used.

[0110] PDMS is a silicone-based elastomer known for its flexibility, transparency, and resistance to environmental factors such as temperature and UV irradiation. It can be easily combined with UV-absorbing materials to form composite materials that maintain flexibility while providing UV blocking properties.

[0111] It will be understood that some non-polymeric elastomer materials, such as natural rubber and latex, can be considered flexible materials that do not originate from a polymer matrix. Such flexible materials do not need a polymer matrix, but can still be combined with or processed with other materials to provide UV blocking properties.

[0112] Flexible materials can be understood as materials that can deform or bend without breaking under applied force or pressure. This property allows the material to absorb and disperse stress, and eventually return to its original shape when the force is removed. In contrast, rigid materials are materials that strongly resist deformation or shatter when subjected to applied force.

[0113] Polymer matrix materials are understood to be flexible due to their unique molecular structure. These materials are composed of long-chain polymer molecules that are entangled and bound together by weak intermolecular forces such as van der Waals forces and hydrogen bonds. This structure allows the polymer chains to slide past each other when subjected to external forces, enabling the material to deform without breaking and absorb energy. When the force is removed, the polymer chains return to their original positions, contributing to the overall flexibility of the material.

[0114] Various embodiments can be implemented using hardware elements, software elements, or a combination of both. Examples of hardware elements may include processors, microprocessors, circuits, application-specific integrated circuits (ASICs), programmable logic devices (PLDs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs), logic gates, registers, semiconductor devices, microchips, and chipsets. Examples of software may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, mobile apps, middleware, firmware, software modules, routines, subroutines, functions, computer implementation methods, procedures, software interfaces, application programming interfaces (APIs), methods, instruction sets, computing code, and computer code.

[0115] This specification describes the present invention with reference to specific examples of embodiments of the invention. However, it will be apparent that various modifications, alterations, substitutions, and changes are possible without departing from the essence of the invention. For the purpose of clarity and concise description, in this specification, configurations are described as part of the same or distinct embodiments, but alternative embodiments having all or part combinations of the configurations described in these distinct embodiments are also envisioned, which are understood to be included within the framework of the invention outlined by the claims. Accordingly, the specification, drawings, and examples should be considered illustrative, not restrictive. The invention is intended to encompass all substitutions, alterations, and changes included in the appended claims. Furthermore, many of the elements described are functional entities that can be implemented as individual components, distributed components, or in combination with other components, in any suitable combination and location.

[0116] In the claims, no reference numerals in parentheses shall be construed as limiting the claims. The word “comprising” shall not exclude the existence of any configuration or step other than those enumerated in the claims. Furthermore, the words “a” and “an” shall not be construed as limiting to “only one,” but rather as meaning “at least one,” and not excluding plural. The words “and / or” shall include all combinations of one or more of the enumerated items relating to the claims. The fact that certain means are described in different claims shall not mean that combinations of these means cannot be advantageously utilized.

[0117] (Note) (Note 1) A stamp for use in imprint lithography, wherein the stamp is configured to form a pattern on a photoresist layer, and the stamp comprises a transparent layer and a plurality of protrusions thereon for imprinting the pattern, wherein the plurality of protrusions are a light-shielding pattern and are made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern.

[0118] (Note 2) The stamp described in Appendix 1, wherein the plurality of protrusions are made of a material containing a polymer matrix in which a light absorber is embedded.

[0119] (Note 3) The stamp described in Appendix 2, wherein the light absorber is uniformly distributed within the polymer matrix.

[0120] (Note 4) The stamp described in Appendix 2 or 3, wherein the light absorber is an ultraviolet (UV) absorber.

[0121] (Note 5) The aforementioned light absorber is a stamp containing powder, as described in any one of the notes 2 to 4.

[0122] (Note 6) The stamp according to Appendix 5, wherein the powder comprises carbon powder, preferably black carbon nanopowder.

[0123] (Note 7) The aforementioned light absorber is a stamp containing a dye, as described in any one of the notes 2 to 6.

[0124] (Note 8) The stamp according to any one of the appendices 2 to 7, wherein the light absorber is a material having UV absorption properties and comprises at least one of the following: nanoparticles, metal-organic frameworks (MOFs), conductive polymers, organic-inorganic hybrid materials, liquid crystals, and inorganic-organic hybrid nanoparticles.

[0125] (Note 9) The polymer matrix is ​​a silicone material such as polydimethylsiloxane (PDMS), as specified in any one of the appendices 1 to 8.

[0126] (Note 10) The transparent material is a stamp made of a polymer matrix material, as described in any one of the appendices 1 to 9.

[0127] (Note 11) The stamp described in any one of the appendices 1 to 10, wherein the transparent layer is made of a first material having a first rigidity, and the plurality of materials are made of a second material having a second rigidity, and the first rigidity is higher than the second rigidity.

[0128] (Note 12) A step of preparing a stamp configured to form a pattern on a photoresist layer, wherein the stamp comprises a transparent layer and a plurality of protrusions extending from the transparent layer, the protrusions being configured to imprint the pattern on the photoresist layer, and the plurality of protrusions being a light-shielding pattern, made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern, The steps include bringing the stamp into contact with the photoresist layer such that the plurality of protrusions imprint the pattern onto the photoresist layer, A step of exposing the photoresist layer to light through the transparent layer, wherein the light passes through the transparent layer and is selectively blocked by the light-shielding pattern formed by the plurality of protrusions, thereby inducing a selective reaction in the exposed region of the photoresist layer. The steps include developing the photoresist layer to selectively remove unreacted regions, thereby forming a desired pattern on the substrate, How to perform imprint lithography, including [specific method / technique].

[0129] (Note 13) A roll-to-roll imprinting system is used, and the roll-to-roll imprinting system includes: A first roller, wherein the transparent layer and the stamp having the plurality of protrusions are attached to the first roller, A second roller, wherein the photoresist layer is mounted on the second roller, and the photoresist layer is provided on a flexible substrate, A light source for applying UV irradiation, A mechanism for advancing the flexible substrate having the photoresist layer between the first roller and the second roller, A system is in place, The aforementioned method, The steps include rotating the first and second rollers so that the transparent layer and the stamp having the plurality of protrusions contact the photoresist layer on the flexible substrate, thereby imprinting the pattern onto the photoresist layer during a roll-to-roll process, The steps include maintaining pressure between the first roller and the second roller during the roll-to-roll process to ensure that the pattern is uniformly imprinted on the photoresist layer, Includes, The method according to Appendix 12, wherein the light source is configured to provide UV irradiation during and / or after imprinting.

[0130] (Note 14) A step of forming a flexible composite material having light absorption properties, wherein the flexible composite material comprises a material including a polymer matrix in which a light absorber is embedded, A step of forming a plurality of protrusions on a transparent layer, wherein the plurality of protrusions are configured to imprint a pattern, and the plurality of protrusions form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern, A method for manufacturing stamps for use in imprint lithography, including...

[0131] (Note 15) The method according to Appendix 14, wherein the composition of the material is selected to have a predetermined target stiffness, and the predetermined target stiffness is determined based on the dimensions and / or geometric shape of the protrusion.

Claims

1. A stamp for use in imprint lithography, wherein the stamp is configured to form a pattern on a photoresist layer, and the stamp comprises a transparent layer and a plurality of protrusions thereon for imprinting the pattern, wherein the plurality of protrusions are a light-shielding pattern and are made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern.

2. The stamp according to claim 1, wherein the plurality of protrusions are made of a material including a polymer matrix in which a light absorber is embedded.

3. The stamp according to claim 2, wherein the light absorber is uniformly distributed within the polymer matrix.

4. The stamp according to claim 2 or 3, wherein the light absorber is an ultraviolet (UV) absorber.

5. The stamp according to any one of claims 2 to 4, wherein the light absorber comprises a powder.

6. The stamp according to claim 5, wherein the powder comprises carbon powder, preferably black carbon nanopowder.

7. The stamp according to any one of claims 2 to 6, wherein the light absorber comprises a dye.

8. The stamp according to any one of claims 2 to 7, wherein the light absorber comprises at least one of the following materials having UV absorption properties: nanoparticles, metal-organic frameworks (MOFs), conductive polymers, organic-inorganic hybrid materials, liquid crystals, and inorganic-organic hybrid nanoparticles.

9. The stamp according to any one of claims 1 to 8, wherein the polymer matrix is ​​a silicone material such as polydimethylsiloxane (PDMS).

10. The stamp according to any one of claims 1 to 9, wherein the transparent material is made of a polymer matrix material.

11. The stamp according to any one of claims 1 to 10, wherein the transparent layer is made of a first material having a first rigidity, and the plurality of materials are made of a second material having a second rigidity, and the first rigidity is higher than the second rigidity.

12. A step of preparing a stamp configured to form a pattern on a photoresist layer, wherein the stamp comprises a transparent layer and a plurality of protrusions extending from the transparent layer, the protrusions being configured to imprint the pattern on the photoresist layer, and the plurality of protrusions being a light-shielding pattern, made of a flexible composite material having light-absorbing properties to form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern, The steps include bringing the stamp into contact with the photoresist layer such that the plurality of protrusions imprint the pattern onto the photoresist layer, A step of exposing the photoresist layer to light through the transparent layer, wherein the light passes through the transparent layer and is selectively blocked by the light-shielding pattern formed by the plurality of protrusions, thereby inducing a selective reaction in the exposed region of the photoresist layer. The steps include developing the photoresist layer to selectively remove unreacted regions, thereby forming a desired pattern on the substrate, How to perform imprint lithography, including [specific method / technique].

13. A roll-to-roll imprinting system is used, and the roll-to-roll imprinting system includes: A first roller, wherein the transparent layer and the stamp having the plurality of protrusions are attached to the first roller, A second roller, wherein the photoresist layer is mounted on the second roller, and the photoresist layer is provided on a flexible substrate, A light source for applying UV irradiation, A mechanism for advancing the flexible substrate having the photoresist layer between the first roller and the second roller, A system is in place, The aforementioned method, The steps include rotating the first and second rollers so that the transparent layer and the stamp having the plurality of protrusions contact the photoresist layer on the flexible substrate, thereby imprinting the pattern onto the photoresist layer during a roll-to-roll process, The steps include maintaining pressure between the first roller and the second roller during the roll-to-roll process to ensure that the pattern is uniformly imprinted on the photoresist layer, Includes, The method according to claim 12, wherein the light source is configured to provide UV irradiation during and / or after imprinting.

14. A step of forming a flexible composite material having light absorption properties, wherein the flexible composite material comprises a material including a polymer matrix in which a light absorber is embedded, A step of forming a plurality of protrusions on a transparent layer, wherein the plurality of protrusions are configured to imprint a pattern, and the plurality of protrusions form a light-shielding pattern that selectively blocks light passing through the light-shielding pattern, A method for manufacturing stamps for use in imprint lithography, including...

15. The method according to claim 14, wherein the composition of the material is selected to have a predetermined target stiffness, and the predetermined target stiffness is determined based on the dimensions and / or geometric shape of the protrusion.

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