Nanoimprint method

Abstract

The invention discloses a nanoimprint method. The nanoimprint method comprises the following steps: providing a substrate; forming an imprinting glue layer on the surface of the substrate; a thermoplastic elastomer film layer is formed on the surface of the imprinting glue layer, is of a solid layer structure in a normal temperature state, has stretchability and can be converted into a liquid state in a heated state; providing a template with a nanoimprint pattern, applying pressure to perform nanoimprint, and curing; and heating to liquefy the thermoplastic elastomer film layer, and stripping the template. According to the nanoimprint method, demolding is more convenient, direct nanoimprint of the hard substrate and the hard template can be achieved, the step of transfer printing of the sub-template is reduced, the technological process is reduced, and the cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of nanoimprinting, and in particular relates to a nanoimprinting method. Background Art

[0002] In the nanoimprint process of hard substrates and hard templates, when the uniform glue on the hard substrate is directly imprinted on the hard template, due to the effect of force and the fact that the substrate is a hard substrate and has no deformation ability, it may be difficult to peel off and demold.

[0003] In the prior art, the solution is to first copy the hard template pattern through a soft substrate such as PC to make a sub-template, and then emboss the sub-template onto the hard substrate. However, the above method increases the process complexity and cost.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The object of the present invention is to provide a nanoimprinting method, which is more convenient to demould and can realize direct nanoimprinting of hard substrates and hard templates, reduce the steps of transferring sub-templates, reduce the process flow, and save costs.

[0006] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0007] A nanoimprinting method, comprising:

[0008] providing a substrate;

[0009] forming an embossed adhesive layer on the surface of the substrate;

[0010] A thermoplastic elastomer film layer is formed on the surface of the embossed rubber layer, wherein the thermoplastic elastomer film layer is a solid layer structure and has stretchability at room temperature, and can be transformed into a liquid state when heated;

[0011] Providing a template with a nanoimprint pattern, applying pressure for nanoimprinting, and curing;

[0012] Heat is applied to liquefy the thermoplastic elastomer film layer, and the template is peeled off.

[0013] In one or more embodiments of the present invention, the thickness of the thermoplastic elastomer film layer is nanometer scale.

[0014] In one or more embodiments of the present invention, during the process of applying pressure for nanoimprinting, the force exerted on the embossing adhesive by the thermoplastic elastomer film layer due to stretching is smaller than the resisting force of the embossing adhesive on the thermoplastic elastomer film layer.

[0015] In one or more embodiments of the present invention, the material of the thermoplastic elastomer film layer includes one of styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, and styrene-ethylene-butylene-styrene block copolymer.

[0016] In one or more embodiments of the present invention, the substrate is a hard transparent substrate; and / or,

[0017] The template is a hard template.

[0018] In one or more embodiments of the present invention, the substrate comprises quartz or glass; and / or,

[0019] The template comprises a silicon template.

[0020] In one or more embodiments of the present invention, forming a thermoplastic elastomer film layer on the surface of the embossed adhesive layer includes:

[0021] Coating a layer of liquid thermoplastic elastomer on the surface of the embossed adhesive layer at a first temperature, wherein the first temperature is higher than room temperature;

[0022] After cooling to room temperature, the liquid thermoplastic elastomer solidifies to form the thermoplastic elastomer film layer.

[0023] In one or more embodiments of the present invention, the first temperature range is greater than 80°C.

[0024] In one or more embodiments of the present invention, before the step of applying pressure to perform nanoimprinting, the method further includes:

[0025] The step of forming a chemically modified layer on the surface of the template having the nanoimprint pattern;

[0026] Before the step of stripping the template, the method further comprises:

[0027] The step of dissolving the chemically modified layer with a strong alkaline solution.

[0028] In one or more embodiments of the present invention, the chemically modified layer comprises an aluminum oxide layer;

[0029] The strong alkaline solution includes sodium hydroxide solution or potassium hydroxide solution.

[0030] Compared with the prior art, the nanoimprint method of the present invention uses a thermoplastic elastomer as a sacrificial layer. Since the thermoplastic elastomer is solid at room temperature and has tensile properties, it can always maintain a film layer state between the substrate and the template during the nanoimprint process to isolate the substrate and the template without affecting the transfer of the nanoimprint pattern on the template. Furthermore, since the thermoplastic elastomer is liquid at high temperatures, the thermoplastic elastomer can be easily converted into a liquid state by heating, thereby peeling off the template and the substrate, and easily demolding.

[0031] The nanoimprinting method of the present invention adopts a method of chemically modifying the surface of the template, so that the template and the substrate are more easily peeled off. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 is a process flow chart of a nanoimprint method according to an embodiment of the present invention;

[0034] Figure 2a to Figure 2c FIG. 1 is a structural diagram of the steps of a nanoimprinting method in one embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0036] As mentioned in the background technology, for nanoimprinting of hard substrates and hard templates, if the hard template is directly imprinted with a uniform glue on the hard substrate, it is difficult to peel off due to the force and the fact that the substrate is a hard substrate and does not have the ability to deform. Therefore, in the prior art, the hard template pattern is first copied through a soft substrate such as PC to make a sub-template, and then the sub-template is imprinted on the hard substrate. However, the above method increases the process complexity and the cost.

[0037] Based on this, the present invention provides a nanoimprinting method, which can improve demoulding efficiency, and is particularly suitable for nanoimprinting demoulding of hard substrates and hard templates, which can reduce the steps of transferring sub-templates, reduce the process flow, and save costs.

[0038] like Figure 1 As shown, the nanoimprinting method in one embodiment of the present invention specifically includes the following steps:

[0039] S1, providing a substrate, and forming an imprinting adhesive layer on the surface of the substrate.

[0040] S2, forming a thermoplastic elastomer film layer on the surface of the embossed rubber layer. The thermoplastic elastomer film layer is a solid layer structure and has stretchability at room temperature, and can be transformed into a liquid state when heated.

[0041] S3, providing a template with a nanoimprint pattern, applying pressure for nanoimprinting, and curing.

[0042] S4, heating to liquefy the thermoplastic elastomer film layer, and peeling off the template.

[0043] The substrate is preferably a hard transparent substrate, such as quartz or glass, and the template is preferably a hard template, such as a silicon template.

[0044] In step S2, a layer of liquid thermoplastic elastomer is coated on the surface of the embossed adhesive layer at a first temperature higher than room temperature. After cooling to room temperature, the liquid thermoplastic elastomer solidifies to form a thermoplastic elastomer film layer on the surface of the embossed adhesive layer. The first temperature range is preferably greater than 80°C.

[0045] The material of the thermoplastic elastomer film layer includes one of styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene-butylene-styrene block copolymer (SEBS). The thickness of the thermoplastic elastomer film layer is nanometer-level. During the process of applying pressure for nanoimprinting, the force exerted on the imprinting glue by the thermoplastic elastomer film layer due to stretching is smaller than the resisting force of the imprinting glue on the thermoplastic elastomer film layer, so that during imprinting, the imprinting glue in the imprinting glue layer can be filled in the nanoimprinting pattern microstructure of the template through the thermoplastic elastomer film layer, thereby maintaining the integrity of the nanoimprinting pattern microstructure transmission.

[0046] In order to further improve the demoulding efficiency, in step S3, before applying pressure for nanoimprinting, a chemical modification layer can be formed on the surface of the template having the nanoimprint pattern. The chemical modification layer is preferably an aluminum oxide layer, and preferably, an atomic layer deposition device (ALD) can be used to grow a 5nm-20nm aluminum oxide layer on the surface of the template 10.

[0047] In step S4, before stripping the template, a strong alkaline solution may be used to soak and dissolve the chemically modified layer. The strong alkaline solution preferably includes a sodium hydroxide solution or a potassium hydroxide solution. The sodium hydroxide solution or the potassium hydroxide solution reacts with the aluminum oxide layer, and the aluminum oxide layer is dissolved, thereby making it easy to demold the substrate and the template.

[0048] Figure 2a to Figure 2c The following is a structural diagram of the steps of the nanoimprinting method of the present invention. Figure 2a to Figure 2c , the nanoimprint method of the present invention is elaborated in detail.

[0049] refer to Figure 2a As shown, a substrate 10 is provided. The substrate 10 is preferably a hard substrate, such as quartz or glass.

[0050] A layer of embossed adhesive is coated on the surface of the substrate 10 to form an embossed adhesive layer 20. The thickness of the embossed adhesive layer 20 ranges from 200 nm to 400 nm, preferably, the thickness is 300 nm. The material of the embossed adhesive layer 20 is preferably UV adhesive.

[0051] A layer of liquid thermoplastic elastomer is uniformly coated on the surface of the embossed adhesive layer 20 at a high temperature, with a thickness ranging from 5nm to 20nm, preferably 10nm. The high temperature is a temperature greater than or equal to 80°C, preferably 80°C to 170°C. After cooling to room temperature, the liquid thermoplastic elastomer solidifies to form a thermoplastic elastomer film layer 30 located on the surface of the embossed adhesive layer 20.

[0052] The material of the thermoplastic elastomer film layer 30 includes one of styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene-butylene-styrene block copolymer (SEBS), which is solid and easily stretchable at low temperatures (under room temperature, less than 60°C). When the thermoplastic elastomer is formed on the surface of the embossed rubber layer 20 in the form of a solid layer structure, it can be easily stretched under the pressure from the template and the resistance from the embossed rubber layer 20, thereby being constructed into a pattern microstructure that is completely adapted to the nano-imprint pattern on the template, so as to be blocked between the embossed rubber layer 20 and the template.

[0053] refer to Figure 2b As shown, a template 40 is provided. The template 40 is preferably a hard template, such as a silicon template.

[0054] The template 40 is used to perform nanoimprinting under a certain pressure, and then exposed and cured. The certain pressure ranges from 5 MPa to 20 MPa, preferably 10 MPa.

[0055] During the process of applying pressure for nanoimprinting, the force exerted on the imprinting adhesive by the thermoplastic elastomer film layer 30 due to stretching is much smaller than the resisting force of the imprinting adhesive on the thermoplastic elastomer film layer 30, so that during imprinting, the imprinting adhesive in the imprinting adhesive layer 20 can be completely filled in the nanoimprinting pattern microstructure of the template 40 through the thermoplastic elastomer film layer 30, maintaining the integrity of the nanoimprinting pattern microstructure transmission. At the same time, the solid thermoplastic elastomer film layer 30 completely isolates the imprinting adhesive layer 20 on the substrate 10 from the template 40.

[0056] refer to Figure 2c As shown, the thermoplastic elastomer film layer 30 or the entire imprint structure is heated to 80°C-170°C, preferably 100°C-120°C or 130°C-160°C. The solid thermoplastic elastomer film layer 30 is converted into a liquid thermoplastic elastomer, so that the substrate 10 and the template 40 can be easily demolded and separated. The liquid thermoplastic elastomer on the imprint glue layer 20 and the template 40 is removed to obtain a nanoimprint structure.

[0057] In the above process steps, in order to further facilitate demolding, a chemical modification layer (not shown) can be formed on the surface of the template 40 having the nanoimprint pattern before the step of applying pressure for nanoimprinting; and before the step of stripping the template 40, a strong alkaline solution is used to dissolve the chemical modification layer. The chemical modification layer is preferably an aluminum oxide layer. The strong alkaline solution is preferably a sodium hydroxide solution or a potassium hydroxide solution. The sodium hydroxide solution or the potassium hydroxide solution reacts with the aluminum oxide layer, and the aluminum oxide layer is dissolved, so that the substrate 10 and the template 40 are easy to demold.

[0058] The nanoimprinting method of the present invention adopts a thermoplastic elastomer film layer as a sacrificial layer. Since the thermoplastic elastomer film layer is solid at low temperature and has the ability to deform and stretch, the substrate and the template can be always isolated during the imprinting process without affecting the transfer of the microstructure on the template. In addition, the thermoplastic elastomer can be recycled and reused.

[0059] The nanoimprinting method of the present invention utilizes the characteristics of thermoplastic elastomers that they are solid at low temperatures and have certain deformation and stretching capabilities, and are liquid at high temperatures. During imprinting, the solid thermoplastic elastomer relies on its deformation and stretching capabilities to always maintain a film layer state between the template and the substrate, and will not affect the transfer of the microstructure on the template; after the imprinting is completed, it is easily converted into a liquid state by heating, thereby peeling off the template and the substrate.

[0060] The nanoimprint method of the present invention firstly spreads a layer of imprint glue on the substrate, and then spreads a layer of liquid thermoplastic elastomer at high temperature. When cooled to room temperature, the thermoplastic elastomer forms a thin elastic film on the surface of the imprint glue, which has a certain deformation and stretching ability. After imprint exposure, a layer of thermoplastic elastomer elastic film is sandwiched between the substrate and the template, and then the thermoplastic elastomer elastic film is changed from solid to liquid by high-temperature heating, so that the substrate and the template can be separated.

[0061] It can be understood that the nanoimprinting method of the present invention is not only applicable to direct imprinting demolding between hard substrates and hard templates, but can also be applied to demolding between other soft substrates and hard templates or soft templates, such as PC, PET, etc., and can also improve the efficiency of nanoimprinting demolding.

[0062] Embodiment 1:

[0063] Choose a hard transparent substrate of quartz or glass, first evenly apply a 300nm thick layer of embossing UV glue, then evenly apply a 10nm thick layer of liquid SBS thermoplastic elastomer at high temperature (about 100°C) and cool it to room temperature.

[0064] After the silicon template is exposed by imprinting at a pressure of 10 MPa, the imprinted UV glue can be completely filled in the microstructure of the silicon template through the solid SBS thermoplastic elastomer, maintaining the integrity of the microstructure transfer. The solid SBS thermoplastic elastomer isolates the imprinted UV glue on the hard transparent substrate from the silicon template.

[0065] After being heated to 100°C, the solid SBS thermoplastic elastomer becomes liquid, allowing the hard transparent substrate to be easily demolded and separated from the silicon template.

[0066] Embodiment 2:

[0067] Choose a hard transparent substrate of quartz or glass, first evenly apply a 300nm thick layer of embossing UV glue, then evenly apply a 10nm thick layer of liquid SIS thermoplastic elastomer at high temperature (about 120°C) and cool it to room temperature.

[0068] After the silicon template is exposed by imprinting at a pressure of 10 MPa, the imprinted UV glue can be completely filled in the microstructure of the silicon template through the solid SIS thermoplastic elastomer, maintaining the integrity of the microstructure transfer. The solid SIS thermoplastic elastomer isolates the imprinted UV glue on the hard transparent substrate from the silicon template.

[0069] After being heated to 120°C, the solid SIS thermoplastic elastomer becomes liquid, allowing the hard transparent substrate to be easily demolded and separated from the silicon template.

[0070] Embodiment 3:

[0071] Choose a hard transparent substrate of quartz or glass, first evenly apply a 300nm thick layer of embossing UV glue, then evenly apply a 10nm thick layer of liquid SEBS thermoplastic elastomer at high temperature (about 150°C), and cool it to room temperature.

[0072] After the silicon template is exposed by imprinting at a pressure of 10 MPa, the imprinted UV glue can be completely filled in the microstructure of the silicon template through the solid SEBS thermoplastic elastomer, maintaining the integrity of the microstructure transfer. The solid SEBS thermoplastic elastomer isolates the imprinted UV glue on the hard transparent substrate from the silicon template.

[0073] After being heated to 150°C, the solid SEBS thermoplastic elastomer becomes liquid, allowing the hard transparent substrate to be easily demolded and separated from the silicon template.

[0074] Compared with the prior art, the nanoimprint method of the present invention uses a thermoplastic elastomer as a sacrificial layer. Since the thermoplastic elastomer is solid at room temperature and has tensile properties, it can always maintain a film layer state between the substrate and the template during the nanoimprint process to isolate the substrate and the template without affecting the transfer of the nanoimprint pattern on the template. Furthermore, since the thermoplastic elastomer is liquid at high temperatures, the thermoplastic elastomer can be easily converted into a liquid state by heating, thereby peeling off the template and the substrate, and easily demolding.

[0075] The nanoimprint method of the present invention is suitable for direct demoulding of a hard substrate and a hard template, reduces the steps of transferring a sub-template, reduces the process flow, and saves costs.

[0076] The nanoimprinting method of the present invention adopts a method of chemically modifying the surface of the template, so that the template and the substrate are more easily peeled off.

[0077] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0078] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A nanoimprinting method, characterized in that: include: providing a substrate; forming an embossed adhesive layer on the surface of the substrate; A thermoplastic elastomer film layer is formed on the surface of the embossed rubber layer, wherein the thermoplastic elastomer film layer is a solid layer structure and has stretchability at room temperature, and can be transformed into a liquid state when heated; Providing a template with a nanoimprint pattern, applying pressure for nanoimprinting, and curing; Heat is applied to liquefy the thermoplastic elastomer film layer, and the template is peeled off.

2. According to the weight, the thickness of the thermoplastic elastomer film layer is nanometer level.

3. The nanoimprint method according to claim 1, characterized in that: During the process of applying pressure to perform nano-imprinting, the force exerted on the embossing adhesive by the thermoplastic elastomer film layer due to stretching is smaller than the resisting force of the embossing adhesive on the thermoplastic elastomer film layer.

4. The nanoimprint method according to claim 1, characterized in that: The material of the thermoplastic elastomer film layer includes one of styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer and styrene-ethylene-butylene-styrene block copolymer.

5. The nanoimprint method according to claim 1, characterized in that: The substrate is a hard transparent substrate; and / or, The template is a hard template.

6. The nanoimprint method according to claim 5, characterized in that: The substrate comprises quartz or glass; and / or, The template comprises a silicon template.

7. The nanoimprint method according to claim 1, characterized in that: A thermoplastic elastomer film layer is formed on the surface of the embossed adhesive layer, comprising: Coating a layer of liquid thermoplastic elastomer on the surface of the embossed adhesive layer at a first temperature, wherein the first temperature is higher than room temperature; After cooling to room temperature, the liquid thermoplastic elastomer solidifies to form the thermoplastic elastomer film layer.

8. The nanoimprint method according to claim 7, characterized in that: The first temperature range is greater than 80°C.

9. The nanoimprint method according to claim 1, characterized in that: Before the step of applying pressure for nanoimprinting, it also includes: The step of forming a chemically modified layer on the surface of the template having the nanoimprint pattern; Before the step of stripping the template, the method further comprises: The step of dissolving the chemically modified layer with a strong alkaline solution.

10. The nanoimprint method according to claim 9, characterized in that: The chemically modified layer comprises an aluminum oxide layer; The strong alkaline solution includes sodium hydroxide solution or potassium hydroxide solution.

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