Release method, imprint method, waveguide manufacturing method, metalens manufacturing method, optical component manufacturing method, wafer, and waveguide device

Abstract

The purpose of the present invention is to provide: a release method and an imprint method using the release method, the release method enabling damage-free forming, reductions in pattern distortion, and high-precision molding even for shapes that are difficult to mold by nanoimprinting, such as line-and-space patterns extending in different directions, high-aspect-ratio pillars, or patterns with varying pattern densities; a wave guide manufacturing method; a metalens manufacturing method; an optical component manufacturing method; a wafer; and a waveguide device.　The release method is characterized in that, when a mold having a pattern part 12 on the surface of a mold substrate 11 made of glass or a resin having a Young's modulus of 10 GPa or more is released from a resin 2 to be molded, a curved part having a curvature that generates a bending moment capable of separating the mold and the resin 2 to be molded is formed in the mold substrate 11, and the curved part is moved along the bonding surface between the mold and the resin 2 to be molded.

Description

Demolding method, imprinting method, waveguide manufacturing method, metalens manufacturing method, optical component manufacturing method, wafer, waveguide device

[0001] The present invention relates to a demolding method for releasing a mold having a pattern portion on the surface of a glass mold substrate from a resin to be molded, as well as an imprinting method, a waveguide manufacturing method, a metalens manufacturing method, an optical component manufacturing method, a wafer, and a waveguide device that utilize the demolding method.

[0002] Nanophotonics, which controls light by forming nano-sized structures on the surfaces of resins, glass, and metals, has attracted attention in industry in recent years as a new optical technology, and its range of applications is expanding to include displays, sensors, and biotechnology.

[0003] Nanoimprinting is a technique that allows for the formation of microstructures on the surface of a resin by pressing a mold with a nano-sized pattern into the resin. Therefore, this technique is used in the production of nanophotonics optical elements as an inexpensive microfabrication technique that can be applied to the surfaces of a wide range of base materials.

[0004] As of 2023, optical components expected to see significant growth among nanophotonics devices include waveguides and metalenses for AR glasses. The method of constructing the input / output couplers of waveguides for AR glasses using diffraction gratings formed by nanoimprinting offers superior mass productivity compared to other methods. Therefore, this method is considered essential for making AR glasses an affordable product for general consumers. Furthermore, metalenses can significantly reduce the size of optical systems by replacing conventional lenses. However, the shapes of these devices are known to be significantly more difficult to manufacture than the shapes of devices conventionally formed by nanoimprinting.

[0005] For example, in the waveguide of AR glasses, light carrying a digital image output from a small display is diffracted by a diffraction grating on a glass substrate called an input coupler and is captured into the glass substrate. The captured light propagates within the glass substrate by total reflection and reaches a diffraction grating called an output coupler either via a diffraction grating that changes the propagation direction of light called a pupil expander, or directly. The output coupler emits the light from the glass substrate to the outside, projecting the digital image onto the human retina.

[0006] In waveguides that transmit images to the retina, such as AR glasses, pattern distortions, defects, and disruptions to the flatness of the transfer area lead to image distortion and reduced resolution. Therefore, in nanoimprinting to form input and output couplers, it is necessary to transfer the mold shape to the glass substrate without distortion.

[0007] Waveguides, in particular, are susceptible to distortion because each product is approximately 3 cm square, which is larger than other nanophotonics products. When manufacturing on a mass production line, multiple products can be molded onto a large-diameter glass wafer and then cut out to produce a large number of products at low cost. However, to maintain product performance, uniform molding is required within the large-diameter wafer, which is 200 mm to 300 mm in diameter.

[0008] Furthermore, the diffraction gratings of the input coupler, pupil expander, and output coupler extend in different directions—0°, 45°, and 90°, respectively. In nanoimprinting, it is difficult to release features that extend in such different directions from the mold. Furthermore, some of these diffraction gratings, especially the input coupler, have tilted shapes to improve diffraction efficiency, further increasing the difficulty of release.

[0009] Metalenses achieve various lens properties by controlling the distribution of phase delay of transmitted light using a dielectric pattern of pillars or fins arranged on a transparent substrate at a pitch shorter than the wavelength. The phase delay distribution is controlled by the diameter of the pillars and the direction of the fins, and an aspect ratio of height to width of approximately 5 to 10 is required. Pattern distortion changes the focus and aberration of the lens, degrading the optical properties of the lens. Suppressing distortion during nanoimprinting is particularly important when molding metalenses with large diameters.

[0010] Nanoimprinting mainly consists of the standard processes of laminating a mold and molding material, UV curing, and demolding. The mold generally used is a mold onto which a pattern is transferred from a master mold 8. Two types of mold structures that are commonly used in industry are shown in Figure 1.

[0011] The mold 9A shown in Figure 1(a) has a pattern portion 1292 made of a resin such as acrylic on the surface of a mold substrate 91 made of a resin with a relatively high Young's modulus, such as PET. In this case, lamination and release of the resin to be molded (hereinafter referred to as "molded resin 22") are controlled by rolls 4 as shown in Figure 2. By laminating the mold 9A and the molded resin 22 from their edges while applying pressure with the rolls 4, the molded resin 22 is filled into the pattern portion 12 of the mold 9A without any air bubbles. In addition, the mold substrate 91 is bent from its edge by the rolls 4, generating stress that releases the mold 9A from the molded resin 22 (see, for example, Patent Documents 1 and 2).

[0012] The mold 9B shown in FIG. 1(b) has a soft silicone resin rubber cushion layer 94 several hundred micrometers thick on the surface of a thin glass back plate 93, and a pattern portion 1292 on that surface. While the aforementioned roll control is sometimes used as a mold release method, as shown in FIG. 3, the opposing mold 9B and the resin-side substrate are gradually brought into contact with each other starting from a certain area to widen the contact area (Patent Document 3), and then, after the resin 22 to be molded has hardened, the contact area is gradually narrowed for mold release (Non-Patent Document 1). The device structure in this case controls the air pressure in the groove on the back surface of the back plate of the mold 9B by switching gas lines. During molding, the air pressure in the groove at the contact point is increased above the surrounding air, causing the mold 9B to protrude in a U-shape and contact the resin-side substrate. During mold release, the air pressure in the groove is reduced, returning the protrusion to its original position and separating it from the resin-side substrate.

[0013] International Publication No. WO2020 / 045101, Patent No. 6483018, Patent No. 5039145, Michael Hornung, Proceedings of the 10th IEEE International Conference on Nanotechnology Joint Symposium with Nano Korea 2010, p. 340, by Shinji Matsui and Yoshihiko Hirai, Nanoimprint Technology, Electronic Information and Communications Company, p. 44

[0014] Here, in the former mold release method using a roll, when nanoimprint molding of a highly difficult shape is performed, a phenomenon called kicking of the pattern occurs during mold release, which becomes a problem.

[0015] In the case of the mold 9A shown in Figure 1(a), mold release can be explained by a beam model as shown in Figure 4. Mold release occurs when the bending energy accumulated by bending the mold substrate 91 of the mold 9A is converted into surface energy (mold release energy) required for cleavage between the pattern portion 1292 and the molded resin 2. Assuming that mold release occurs slowly and quasi-statically, and assuming that the height of the mold 9A at position A is h, the distance from position A to the cleavage position B is C, the Young's modulus of the mold substrate is E, the thickness of the mold substrate is d, and the surface energy (= mold release energy) is γ, the equilibrium distance C derived from Obreimoff's equation, where the bending energy and surface energy are balanced, is ０ is expressed as the following formula 1 (Non-Patent Document 2).

[0016] 5(a), when the mold substrate 91 is released, the surface that contacts the resin 22 expands due to bending. As a result, when the nanoimprint is released, the mold pushes the resin 22 sideways due to the expansion of the substrate 91, causing a kick as shown in FIG. 5(b) in the transferred pattern 22. If the kick is large, it can damage the pattern 22.

[0017] If the aspect ratio is about 1, the kick of the pattern 22 is not so great, but if the aspect ratio is 3 or more, the kick of the pattern 22 becomes so great that the molded pattern 22 is knocked down by the kick when released from the mold.

[0018] When the pattern 22 to be released is a line-and-space pattern extending in one direction, kicking of the pattern 22 by the mold 9 can be avoided by aligning the release direction with the extension direction, but as mentioned above, in an AR glass waveguide, the extension directions of the input coupler and output coupler are orthogonal, so it is necessary to release the pattern perpendicular to at least one of them, which can lead to the pattern 22 falling over due to the kick as shown in Figure 5(b). Furthermore, in a metalens formed with pillars with an aspect ratio of 5 or more, a pillar-shaped pattern is released from a hole-shaped mold, and there is a problem in that kicking of this pattern 22 cannot be avoided.

[0019] In the case of the mold 9B shown in FIG. 1(b), the back plate 93 is thin, so the bending energy is small, and the energy that causes demolding is primarily energy stored as elongation of the silicone rubber. This energy is converted into surface energy during cleavage, resulting in demolding. This method can mitigate kicking during demolding by elongating the rubber. However, as shown in FIG. 6(a), as the energy required for demolding increases, the silicone rubber elongates more, which increases the popping during cleavage, reducing the kicking mitigation effect. Furthermore, because the silicone elongates, a delay occurs in demolding relative to the external demolding action. As shown in FIG. 6(b), the force applied to demolding pulsates between when the silicone rubber stretches and when it cleaves, resulting in uneven demolding.

[0020] 1(a) uses a resin mold substrate 91, which inevitably causes distortion due to the flexibility of the mold substrate 91 when the mold 9A is bonded to the resin 22 to be molded, resulting in the problem of pattern deformation. Also, the mold 9B in FIG. 1(b) has a soft rubber cushion layer 94 disposed thereon that is as thick as or thicker than glass, which causes the same problem as above.

[0021] In AR glass waveguides, the diffraction gratings of the input and output couplers have different line-and-space pattern extension directions, as mentioned above. Therefore, to address the difficulty of molding, the respective patterns may be formed on both sides of the substrate to be molded. In this case, the newly formed front-side pattern must be aligned with the first formed back-side pattern via a mark. As shown in Figure 7, misalignment can be classified into (a) translation, (b) rotation, and (c) distortion. Misalignment due to distortion of the substrate, in particular, can cause fluctuations in pattern pitch and linearity, reducing resolution.

[0022] The flatness of the molded device also affects the device's characteristics. As shown in Figure 8(a), the AR glass waveguide 6 has a transfer section 63 with no pattern between the input coupler 61, pupil expander, and output coupler 62. In areas with different pattern densities, if the substrate is flexible, bending will occur in the transfer section 63, as shown in Figure 8(b). When this bending occurs, variations occur in the reflection angle of light transferred by total internal reflection, leading to a deterioration in image resolution.

[0023] The above-mentioned deformation of the pattern due to molding affects the properties of the waveguides and metalenses for AR glass formed by nanoimprinting, and there is a need to solve this problem.

[0024] Therefore, an object of the present invention is to provide a demolding method that can form even shapes that are difficult to mold by nanoimprinting, such as lines and spaces extending in different directions, pillars with high aspect ratios, and patterns with different pattern densities, without damage, reduce pattern distortion, and achieve highly accurate molding.

[0025] In order to achieve the above object, the demolding method of the present invention is for demolding a mold having a pattern portion 12 on the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more from a resin 2 to be molded, and is characterized in that a curved portion having a curvature that generates a bending moment capable of separating the mold and the resin 2 to be molded is formed on the mold substrate, and the curved portion is moved along the bonding surface of the mold and the resin 2 to be molded.

[0026] In this case, the curved portion is formed at the end portion so that the end portion of the bonding surface between the mold and the resin 2 to be molded will be torn at the start of the demolding.

[0027] The edge of the mold substrate is bonded to the resin-side substrate, which holds the molded resin 2 on its surface, so that the edge has an outer edge that extends outward. A force is applied to at least a portion of the outer edge to generate a bending moment that causes the edge to split. Methods for applying a force to at least a portion of the outer edge include contacting a rigid body such as a rod with the mold surface and pushing it, and applying a gas pressure differential p between the front and back sides of the mold substrate to form the curved portion. The latter method is preferred because the force is not concentrated in a local area and the lack of direct contact with the object prevents damage to the processed surface.

[0028] When a uniform pressure p is applied to a cantilever beam with length L, width b, thickness d, and Young's modulus E, the deflection h is calculated as follows. In the formula, I is the moment of inertia (I = bd ３ / 12).

[0029] In this case, if the deflection h caused by the mold substrate being subjected to the differential pressure p complies with equation (2) and the distance L is equal to or greater than the distance Co in equation (1) at which the bending energy of the mold substrate and the surface energy caused by the cleavage are in equilibrium, the cleavage will proceed due to the bending moment caused by the pressure p. Substituting equation (2) into equation (1) yields equation (3).

[0030] Therefore, since L≧Co, when the Young's modulus of the glass is E, the thickness of the mold substrate is d, and the surface energy is γ, the following formula (4) is obtained: It is sufficient to satisfy the following.

[0031] Furthermore, when the surface energy γ is 1.5 N or less and the differential pressure p is 0.2 MPa or less, it is preferable that L and d satisfy the following relationship: L≧4.6+8(d−0.4) / 1.1 (5).

[0032] Furthermore, when the Young's modulus of the glass is E, the thickness of the mold substrate is d, the surface energy is γ, and the fracture stress of the glass is Mc, the following relationship is satisfied: d≧21Eγ / Mc ２It is preferable that the following formula (6) is satisfied: In this case, for example, the thickness of the mold substrate can be set to 0.3 mm or more.

[0033] Alternatively, the back surface of the mold substrate may be partially suctioned from the end to raise it to a height H, deforming the curved portion so that the cross section of the curved portion becomes S-shaped, and the curvature of the curved portion may be set under quasi-static conditions such that the curvature is the curvature when the energy released when the bending energy accumulated in the mold substrate at the contact surface with the resin to be molded 2 is released is balanced with the surface energy generated when a cleavage occurs between the mold and the resin to be molded 2, and the area where the back surface of the mold substrate is suctioned may be gradually expanded from the end to increase the height H portion, thereby facilitating the release of the mold from the resin to be molded 2.

[0034] Furthermore, the mechanism for gradually widening the area where the rear surface of the mold substrate is sucked from the edge is implemented by periodically arranged suction slits that are sequentially switched to vacuum evacuation, and the Young's modulus of the glass is E, the thickness of the mold substrate is d, the surface energy is γ, the pitch of the suction slits is Pi, the height of half the maximum height H of the mold substrate by suction is h, and the distance between the position on the surface of the molded resin 2 where the height of the mold substrate is h and the position of the edge of the bonding surface of the mold and the molded resin 2 is C. ０ Then, the height h is calculated by the following formula (7): The present invention is characterized in that:

[0035] Furthermore, the imprinting method of the present invention involves bonding a mold having a pattern portion 12 on the surface of a mold substrate made of glass or a resin with a Young's modulus of 10 GPa or more to a resin 2 to be molded, and transferring a fine structure using the pattern portion 12, and is characterized in that the above-mentioned mold release method of the present invention is used when releasing the mold from the resin 2 to be molded.

[0036] The method for manufacturing a waveguide of the present invention is characterized in that a mold having a pattern portion 12 on the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more is bonded to a resin 2 to be molded, and a fine structure as a waveguide is transferred by the pattern portion 12, and the mold releasing method of the present invention described above is used when releasing the mold from the resin 2. In this case, the waveguide corresponds to a waveguide for AR or the like.

[0037] Furthermore, a metalens manufacturing method of the present invention involves bonding a mold having a pattern portion 12 and a resin 2 to be molded onto the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more, and transferring a microstructure as a metalens using the pattern portion 12, and is characterized in that the mold is released from the resin 2 to be molded using the above-described demolding method of the present invention.

[0038] Furthermore, the imprinting method of the present invention involves bonding a mold having a pattern portion 12 on the surface of a mold substrate made of glass or a resin with a Young's modulus of 10 GPa or more to a resin to be molded 2, and transferring a fine structure using the pattern portion 12. The imprinting method is characterized by comprising: a bonding step in which the pattern portion 12 side of the mold substrate is placed opposite the resin side of a resin side substrate that holds the resin to be molded 2 on its surface, and the two are bonded under reduced pressure; a pressurizing step in which the bonded mold substrate and resin side substrate are pressurized at 0.1 MPa or more; a resin curing step in which, after the pressurizing step, the resin to be molded 2 is irradiated with light to harden it; and a demolding step in which a curved portion is formed in the mold substrate, the curved portion having a curvature that generates a bending moment capable of separating the mold and the resin to be molded 2, and the curved portion is moved along the bonding surface of the mold and the resin to be molded 2.

[0039] In this case, the mold releasing step is characterized in that the radius of curvature locally given to the curved portion of the mold substrate is 50 cm or more.

[0040] Furthermore, if the minimum radius of curvature given by the mold is Ro (=50 cm), the release energy between the mold and the resin 2 to be molded is γ, and the Young's modulus of the mold substrate is E, then the thickness d of the mold substrate is The present invention is characterized in that:

[0041] In addition, the upper limit of the lateral movement of the replica pattern during demolding is set to Δ ０ Then, the thickness d of the mold substrate is The present invention is characterized in that:

[0042] In addition, the upper limit Δ ０ is characterized in that the distance is 300m or less.

[0043] The mold has a flat portion sandwiched between the pattern portions 12, and the pressing step is characterized in that the radius of curvature of the surface of the flat portion during pressing is 5 m or more.

[0044] The pressure application step is characterized in that the temperatures of the mold substrate and the resin side substrate are increased during the application of pressure, and the temperature increase is characterized in that the temperature increase rate is set to 1° C. / second or less.

[0045] The mold substrate has a thermal expansion coefficient that is the same as that of the resin-side substrate or that is within ±10% of that of the resin-side substrate.

[0046] The mold substrate is also characterized in that it is made of high refractive index glass having a refractive index of 1.9 or more, and the mold substrate is made of glass having a thermal expansion coefficient of 7 ppm / °C or more.

[0047] Furthermore, the method for manufacturing an optical component of the present invention is characterized in that a waveguide or a metalens is manufactured by the imprint method of the present invention described above.

[0048] Furthermore, the wafer of the present invention is a wafer of 200 mm or more that is mounted with optical components each consisting of a pattern of a plurality of AR waveguides or metalenses before dicing, and is characterized in that distortion of the pattern of each mounted optical component within the wafer is 1 μm or less.

[0049] Furthermore, the waveguide device for AR glasses of the present invention is characterized in that the radius of curvature of the surface of the unpatterned light transfer section located between either the input coupler and the output coupler, the input coupler and the pupil expansion diffraction grating, or the pupil expansion diffraction grating and the output coupler is 5 m or more.

[0050] By utilizing the mold release method of the present invention, even shapes that are difficult to mold by nanoimprinting, such as lines and spaces extending in different directions, pillars with high aspect ratios, and patterns with different pattern densities, can be formed without damage, pattern distortion can be reduced, and highly accurate molding can be achieved.

[0051] 1 is a schematic cross-sectional view showing a conventional mold. FIG. 1 is a schematic cross-sectional view showing an example of a conventional imprinting method. FIG. 1 is a schematic cross-sectional view showing another example of a conventional imprinting method. FIG. 2 is a schematic cross-sectional view showing a beam model for explaining demolding. FIG. 3 is a schematic cross-sectional view for explaining collapse due to kicking of a pattern. FIG. 4 is a diagram for explaining pulsation of the force applied to demolding. FIG. 5 is a diagram for explaining classification of alignment deviations. FIG. 6 is a schematic cross-sectional view showing the configuration of a waveguide for AR glass. FIG. 7 is a schematic cross-sectional view showing the magnitude of kicking during demolding of (a) a mold made of a glass mold substrate and (b) a mold made of a resin mold substrate. FIG. 8 is a schematic cross-sectional view showing the state during peeling using the demolding method of the present invention. FIG. 9 is a schematic cross-sectional view showing the state at the start of demolding using the demolding method of the present invention. FIG. 10 is a diagram showing the relationship between the height h of an edge and the force P applied to the edge. FIG. 11 is a diagram for explaining processes when the mold substrate does not have an outer edge relative to the resin-side substrate (a) and when it does (b). FIG. 12 is a diagram showing a method for cleaving the mold and the resin 2 to be molded at the edge. FIG. 13 is a graph showing the relationship between the differential pressure p and the minimum distance L at which demolding begins. FIG. 14 is a graph showing the relationship between the thickness d of the mold substrate and the minimum distance L. 1 is a graph showing the relationship between the thickness d of the mold substrate and bending stress.

[0033] FIG. 1 is a graph showing the relationship between the release energy γ and height h for each glass thickness and equilibrium distance.

[0034] FIG. 1 is a graph showing the range of Young's modulus E and thickness d of the mold substrate that satisfies the radius of curvature of 50 cm or more and the lateral movement Δ or less. A schematic cross-sectional view showing a doubly supported beam model for explaining the deflection of the mold substrate when pressure is applied. A diagram showing the molding process of the resin 2 to be molded by nanoimprinting. A diagram explaining a method for calculating strain within a wafer. (a) A diagram showing the strain distribution within a wafer of the fourth molding pattern molded continuously using the same mold, and (b) A diagram showing the average strain distribution of 16 moldings molded using the same mold. A diagram showing an example of molding a high refractive index, wide viewing angle waveguide. A diagram explaining the waveguide pattern for AR glass used in the simulation. A diagram showing the results of a simulation of the resolution of an output image using models with different radii of curvature of the surface of the transfer section. A diagram showing the characteristics when the surface of the transfer section is deformed convexly upward. A photograph comparing the release of a glass substrate mold and the release of a resin substrate mold.(a) The stretching direction of four tilted gratings and (b) an SEM photograph of the formed result.

[0052] The following describes the demolding method of the present invention for releasing the mold 1 from the resin (the molded resin 2) to be molded. To reduce the pattern kick observed in the past, it is possible to reduce the demolding energy or to generate large stress with slight bending of the substrate without utilizing the elongation of the cushion layer 94 as in the conventional mold 9B. To reduce the demolding energy, it is possible to use a combination of a molding resin and a molded resin 2 that can be released with small stress. However, as shapes become higher in aspect ratio, the contact surface between the molding resin and the molded resin 2 increases, making it difficult to reduce the demolding energy. Therefore, the only method to reduce the pattern kick is to generate large stress with slight bending of the substrate. To generate large stress with slight bending of the substrate, it is necessary to use a mold substrate 11 with a high Young's modulus for the mold 1.

[0053] The magnitude of the kick at the time of release, Δ, is calculated by dividing the equilibrium distance by C ０ , and the tensile rate of the mold 1 in the horizontal direction is F, then Δ=C ０ The tensile modulus F can be calculated by the following equation: F = (R + d / 2) / R, where R is the radius of curvature. The radius of curvature R can be calculated from the height h of the release end and the equilibrium distance C from the above-mentioned formula (1). ０ From this, the radius of curvature R of the substrate at the time of mold release can be calculated.

[0054] Figure 9 shows the magnitude of kick at the time of demolding for (a) a mold 1 consisting of a 400 μm thick glass mold substrate 11 and (b) a mold 9 consisting of a resin mold substrate. Here, the Young's modulus of the glass mold substrate 11 is 80 GPa, and the Young's modulus of the resin mold substrate is 4 GPa. Both pattern portions 12 are line and space with a height of 300 nm, a pitch of 200 nm, and a pattern width of 100 nm. The Young's modulus of the resin 2 to be molded is 4 GPa. The equilibrium distance at a height h of 300 nm is C ０ｈ＝300 Then, the magnitude of the kick Δ at the time of mold release is Δ = C ０ｈ＝300× (R + d / 2) / R. Calculation reveals that the kick at mold release of the mold 1 made of the glass mold substrate 11 is 110 nm, while the kick at mold release of the mold 9 made of the resin mold substrate is 230 nm, meaning that the kick at glass mold substrate 11 is reduced to about half of that of the resin mold substrate.

[0055] For the above reasons, it is preferable to use a mold substrate 11 with a high Young's modulus for the mold 1 used in the present invention. For example, a mold substrate 11 made of glass with a high Young's modulus or a resin with a Young's modulus of at least 10 GPa or more and having a pattern portion 12 on its surface is preferably used. The shape of the pattern portion 12 is not particularly limited, but examples include lines and spaces extending in different directions and pillars with a high aspect ratio. The material of the pattern portion 12 is not particularly limited as long as it is usable for imprint molding, and for example, a resin such as acrylic can be used. Alternatively, the mold 1 may be one in which the mold substrate 11 and the pattern portion 12 are integrally formed from glass.

[0056] The resin to be molded 2 may be any resin that can be used for imprinting, such as a photocurable resin, and examples of such photocurable resins include compounds containing unsaturated hydrocarbon groups such as vinyl groups and allyl groups, such as epoxide-containing compounds, (meth)acrylic acid ester compounds, vinyl ether compounds, and bisallylnadiimide compounds.

[0057] In the demolding method of the present invention, first, a curved portion having a curvature that generates a bending moment capable of separating the mold 1 from the molded resin 2 is formed on the mold substrate 11. Then, the curved portion is moved along the bonding surface of the mold 1 and the molded resin 2. In this way, the mold 1 and the molded resin 2 can be separated by the bending moment generated by the curved portion.

[0058] Furthermore, in the case of a mold substrate 11 made of glass, the radius of curvature of the bend of the mold substrate 11 becomes very large. For example, in the calculation example explained using Figure 9, the radius of curvature of the bend of the mold substrate 11 is very large, at 489 mm (diameter 978 mm). If demolding is attempted using a roll 4 as shown in Figure 2, the diameter of the roll 4 is too large, making it unavoidable to increase the size of the equipment. Although the radius of curvature can be reduced by reducing the glass thickness, this cannot be used because it would lead to glass breakage, as described below. For this reason, a highly accurate mechanism is needed to locally generate a large curvature without damaging the glass.

[0059] The condition under which the glass mold substrate 11 does not break is as follows: if the fracture stress due to bending is Mc and the Young's modulus of glass is E, then once the nanoimprint release energy γ is determined, the minimum required glass thickness d is ｃ Furthermore, once the thickness of the glass is determined, the height h to which the mold substrate 11 is raised during mold release can be determined.

[0060] As described above, the height h of the mold substrate 11 at the time of mold release and the equilibrium distance C ０ Therefore, the conceivable radius of curvature would be extremely large, and a roll 4 such as that shown in Figure 2 would need to have a diameter of 1 m or more, which is not practical, and it would be necessary to locally generate a large curvature in the mold substrate 11. On the other hand, a method of locally forming a U-shaped convex portion in the mold substrate 11, as shown in Figure 3, can locally generate a large curvature. However, at a thickness that satisfies the conditions for direct mold release using the bending energy of the mold substrate 11 and for the mold substrate 11 not to crack, the radius of curvature is large, and in the case of U-shaped contact, the flat area of ​​the contact surface is limited.

[0061] Therefore, in the present invention, the mold 1 and the resin to be molded 2 are bonded together in a flat state under vacuum, and when releasing the mold, a peeling device is used that can suck the cross section of the mold substrate 11 into an S-shape in order to control the height h to a constant value to create the bending required for release (see Patent No. 6377956).

[0062] Figure 10 shows a system using the above-described peeling device. A suction slit 5 is arranged on the back of the mold 1 via a porous cushion. Here, a low pressure is applied by a vacuum pump from the edge slit, lifting the mold 1 to form an S-shaped cross-section. Vacuum is then drawn sequentially through the slits, creating a pressure difference with the chamber, lifting the mold 1 while moving the corner of the S-shape, and peeling proceeds. The pulling height H can be controlled by the pressure difference and the hardness of the intervening sponge. The device used in the demolding method of the present invention does not necessarily have to be the above-described peeling device; any device can be used as long as it can be used to move the S-shaped cross-section while increasing the area lifted from the edge of the mold 1.

[0063] Furthermore, when the mold 1 and the resin 2 to be molded are completely bonded together, the curved portion described above must be formed at the end of the bonded surface between the mold 1 and the resin 2 to cause a cleavage at that end when demolding begins. This allows a bending moment to be generated in the mold substrate 11 at that end.

[0064] Regarding this point, we will explain the case where the mold 1 and the resin 2 to be molded are bonded in a flat state under vacuum, and then the mold 1 and the resin 2 to be molded are released in a system as shown in Figure 11. In a beam model as shown in Figure 4, when the release of the bending energy of the beam and the increase in energy due to peeling are balanced, the force P applied to a certain position of the beam is expressed by the following formula (8), where E is the Young's modulus of the glass, b is the width of the mold substrate 11, d is the thickness of the glass, γ is the release energy, and h is the height at which the force P is applied. In the formula, I is the second moment of area (I=bd ３ / 12).

[0065] Figure 12 shows the relationship between the edge height h and the force P applied to the edge, assuming a Young's modulus E of 80 GPa, a glass width b of 1 m, a glass thickness of 0.7 mm, and a demolding energy γ of 1 N / m. From the equation and the diagram, the value of P is infinite when the edge begins to peel, i.e., when the height h is 0. Therefore, as shown in Figure 13(a), it is difficult to bend the glass to peel the edge of a mold 1 and a molded resin 2 bonded to identically sized substrates, because no bending moment is applied for peeling. In this case, mechanically creating a cleavage at the bonded edge is considered (see Patent No. 6377956). However, this method poses problems such as particle generation, pattern unevenness in the cleavage area, and reduced processing speed.

[0066] 13(b), if the edge of the mold substrate 11 is bonded so as to have an outer edge 15 that extends outward beyond the edge of the resin-side substrate 21 that holds the molded resin 2 on its surface, the mold substrate 11 can be bent in advance to form a curved portion. This generates a bending moment that causes cleavage at the edge of the bonded surfaces of the mold 1 and the resin-side substrate 21, causing cleavage at the bonded edge between the mold 1 and the resin-side substrate 21, thereby facilitating mold release. To bend the mold substrate 11 to form a curved portion, a gas pressure differential p is applied between the front side 15 and back side 16 of the mold substrate 11 at least in part of the outer edge 15 of the mold substrate 11.

[0067] When suction units such as the suction slit 5 are provided as in the peeling device described above, the first suction unit must be positioned outside the edge of the resin-side substrate 21. That is, to start the demolding process by cleaving without using a mechanical tool such as a blade, any of the methods shown in Figures 14(a) to 14(c) can be used. In all of Figures 14(a) to 14(c), the edge of the mold substrate 11 is bonded so that it has an outer edge 15 that extends beyond the edge of the resin-side substrate 21 that holds the molded resin 2 on its surface. In Figure 14(a), the differential pressure suction area located above the mold substrate 11 is formed to be the same size as the mold substrate 11. In Figure 14(b), the differential pressure suction area is smaller than the mold substrate 11 but larger than the resin-side substrate 21. In Figure 14(c), the differential pressure suction area is the same size as the resin-side substrate 21. However, an area that can be evacuated and is separated from the chamber by a seal or the like is provided around the differential pressure suction area, allowing differential pressure suction to be applied to the mold 1. In this way, in any of the cases shown in Figures 14(a) to 14(c), a bending moment is applied to the end of the resin-side substrate 21, making it possible to release the mold.

[0068] Next, we will explain how large the size of the differential pressure suction region should be for the resin side substrate 21. This will be explained using the system of FIG. 14(c) in FIG.

[0069] In Figure 14(c), the edge of the mold substrate 11 has an outer edge 15 that extends beyond the edge of the resin-side substrate 21. The differential pressure suction area is the same size as the resin-side substrate 21. However, around the differential pressure suction area, an area that is separated from the chamber by a seal or the like and can be evacuated is provided, providing an area where the mold 1 can be subjected to differential pressure suction. A portion of the outer edge 15 of the mold substrate 11 is separated by a flexible seal and evacuated, causing a force due to differential pressure p to be applied to the front and back of the mold substrate 11. Here, the edge of the differential pressure suction area of ​​the mold substrate 11 is designated A, and the edge of the resin-side substrate 21 is designated B. The distance from edge A to edge B, i.e., the distance over which the mold substrate 11 is subjected to differential pressure p, is designated L.

[0070] In this case, the distance L at which the mold substrate 11 is subjected to the differential pressure p is defined as the distance C from the position where the differential pressure p is applied to the mold substrate 11 to the end of the resin-side substrate 21 when the bending energy of the mold substrate 11 at the differential pressure p and the surface energy generated by the cleavage are balanced. ｐ In other words, the equilibrium distance in equation (1) derived from the deflection h due to the differential pressure p is If the distance L from the end A of the differential pressure suction area of ​​the mold substrate 11 to the end B of the resin side substrate 21 is longer, the bending moment M = pL ２ The minimum bending moment M required for splitting ０ = PC ０ ２ When a uniform pressure p is applied to a cantilever beam with length L, width b, thickness d, and Young's modulus E, the deflection h that occurs is expressed as equation (9). In the equation, I is the moment of inertia (I = bd ３ / 12).

[0071] In this case, if the deflection h caused by the mold substrate 11 being subjected to the differential pressure p follows equation (2), and the distance L is equal to or greater than the distance Co in equation (1) at which the bending energy of the mold substrate 11 and the surface energy caused by the cleavage are in equilibrium, the cleavage will proceed due to the bending moment caused by the pressure p. Substituting equation (2) into equation (1), we get:

[0072] Therefore, since L≧Co, if the Young's modulus of glass is E, the thickness of the mold substrate 11 is d, and the surface energy is γ, then: It is sufficient to satisfy the following.

[0073] In addition, the stress σ applied to the substrate at this time is Z is the section modulus Z = bd ２ / 6.

[0074] Therefore, if the fracture stress of the glass used for the mold substrate 11 is Mc, the thickness d at which the mold substrate 11 does not break is: d≧21Eγ / Mc ２ ...Equation (11) is obtained.

[0075] 15 shows the relationship between the differential pressure p and the minimum distance L between the position where the differential pressure is applied and the end of the resin-side substrate 21 to generate the bending moment that initiates demolding. The thicknesses d of the mold substrate 11 were 0.4 mm and 0.7 mm, and the demolding energies γ were 1 N / m, 1.5 N / m, 2 N / m, and 2.5 N / m. The Young's modulus E of the glass was 80 GPa.

[0076] 16 shows the relationship between the thickness d of the mold substrate 11 and the minimum distance L between the edge of the resin-side substrate 21 and the position where the differential pressure is applied to generate the bending moment at which demolding begins. The demolding energy γ was 1.5 N / m, the differential pressure P was 0.2 MPa, and the Young's modulus E of the glass was 80 GPa. From FIG. 16, the distance L (mm) was approximately given by: L≧4.6+8(d−0.4) / 1.1 ...Equation (12).

[0077] 17 shows the relationship between the thickness d of the mold substrate 11 and the bending stress. The demolding energies γ were set to 1 N / m, 1.5 N / m, 2 N / m, and 2.5 N / m. The Young's modulus E of the glass was set to 80 GPa. From FIG. 17, it can be seen that for a glass breaking strength of 100 MPa when demolded with a demolding energy of 1.5 N / m, the thickness d of the mold substrate 11 must be 0.3 mm or more, preferably 0.4 mm or more.

[0078] 15(a) shows that, under conditions where the glass does not break, if the thickness d of the mold substrate 11 is 0.7 mm, and the minimum protrusion length of the differential pressure application area is 8 mm or more, even workpieces with a maximum demolding energy of 2 N / m can be demolded under realistic differential pressure conditions of 0.2 MPa. Considering the mounting margin, it is preferable to double the protrusion length of the differential pressure application area to 16 mm or more.

[0079] Furthermore, when the thickness d of the mold substrate 11 is 0.4 mm, if the minimum protrusion length of the differential pressure application area is set to 5 mm or more, it is possible to release even workpieces with a maximum release energy of 1.5 N / m under realistic differential pressure conditions of 0.2 MPa. Considering the mounting margin, it is preferable to double the protrusion length of the differential pressure application area to 10 mm or more.

[0080] Next, we will explain the conditions under which mold release continues after the edge of the resin-side substrate 21 begins to cleave and mold release begins. Here, the back surface of the mold substrate 11 is partially suctioned from the edge, lifting it to a height H and deforming it so that the cross section of the curved portion is S-shaped. Furthermore, mold release proceeds under quasi-static conditions, such that the curvature of the curved portion is the curvature at the time when the energy released when the bending energy accumulated in the mold substrate 11 at the contact surface with the resin 2 to be molded is released is balanced with the surface energy generated by the resulting cleavage between the mold 1 and the resin 2 to be molded. Under these conditions, we will explain the case where the suction area is gradually expanded from the edge to expand the height H portion, thereby promoting the release of the mold 1 from the resin 2 to be molded.

[0081] The mechanism for gradually expanding the area where the back surface of the mold substrate 11 is sucked from the edge is one that uses periodically arranged suction slits 5 that are sequentially switched to vacuum evacuation, as shown in Figure 10. As shown in Figure 10, if the maximum height of the mold substrate 11 due to suction is H, the boundary position on the surface of the molded resin 2 where the height of the mold substrate 11 is H is A, and the position of the edge of the bonding surface between the mold 1 and the molded resin 2 is B, then the position C on the surface of the molded resin 2 where the mold 1 substrate is at a height h that is half the maximum height H is located at the midpoint between A and B. When the separation of the mold 1 and the molded resin 2 progresses quasi-statically, the distance c between A and C and between B and C is calculated from equation (1) as follows: This becomes:

[0082] In addition, the lower limit of the suction slit width is about 1 mm and the lower limit of the pitch is about 2 mm in terms of processing and vacuum exhaust efficiency. When the thickness of the glass is fixed, the equilibrium distance C is set to facilitate precise control of nanoimprint release and to achieve continuous and smooth peeling. ０ must be larger than the slit pitch Pi. ０ It is necessary to set the height h to be at least twice the slit pitch Pi or more, which is half the height H of the S-shape. ０ ≧mPi (m=2), the height h at this time is calculated from equation (2) as follows: The thickness of the glass is 0.4 mm and 0.7 mm, respectively. ０The range of height h when the thickness is 5 mm, 10 mm, and 15 mm is shown in FIG.

[0083] In order to make the height H (2h) easy to control to about 100 μm to 200 μm (h is 50 μm to 100 μm), as shown in FIG. 18, at a thickness of 0.7 mm, ０ is 10mm to 15mm, and C is 0.4mm thick. ０ In this case, by setting the pitch of the suction slits 5 to about 3 mm, it becomes possible to smoothly change the expansion of the release area.

[0084] [Imprinting Method] The imprinting method involves bonding a mold 1 having a pattern portion 12 on the surface of a mold substrate 11 made of, for example, glass or a resin with a Young's modulus of 10 GPa or more to a resin 2 to be molded, thereby transferring a microstructure using the pattern portion 12. The imprinting method mainly comprises a bonding step, a pressurizing step, a resin curing step, and a demolding step. In the bonding step, for example, the pattern portion 12 side of the mold substrate 11 is placed opposite the resin side of a resin-side substrate 21 that holds the resin 2 on its surface, and the two substrates are bonded together under reduced pressure. In the pressurizing step, the bonded mold substrate 11 and resin-side substrate 21 are pressed together. The pressure may be, for example, 0.1 MPa or more. In the resin curing step, the resin 2 is irradiated with light after the pressurizing step to harden it. In the demolding step, the mold 1 is released from the resin 2 to be molded. The demolding method of the present invention described above can be used in the demolding step.

[0085] In this case, when the imprint method is used in the method for manufacturing a waveguide, the fine structure of the waveguide is transferred by the pattern portion 12 of the mold 1, and then the above-described demolding method of the present invention is used. Note that the waveguide in question includes a waveguide for AR.

[0086] Furthermore, when an imprinting method is used in a metalens manufacturing method, a microstructure as a metalens is transferred using the pattern portion 12 of the mold 1, and then the above-described mold release method of the present invention is used.

[0087] In the imprinting method, the main cause of distortion in the molding target is unwanted deformation of the mold substrate 11 in each of the steps of laminating, pressing, resin curing, and demolding. Therefore, in order to reduce the distortion, it is preferable to eliminate or reduce such deformation of the mold substrate 11 in each step as follows.

[0088] (A) Substrate Material. It is preferable to appropriately design the Young's modulus E and thickness d of the mold substrate 11 so that the mold 1 can exert a release force from the resin 2 to be molded with slight deflection (a radius of curvature of 50 cm or more) during the demolding process. On the other hand, it is also necessary to limit the thickness d of the mold substrate 11 to prevent large pattern kicks caused by expansion due to deflection of the mold substrate 11. Furthermore, the mold 1 may have a flat portion sandwiched between the pattern portions 12 to form the AR glass transfer portion 63. In this case, it is preferable to appropriately design the Young's modulus E and thickness d of the mold substrate 11 so that the radius of curvature of the surface of the flat portion during the pressurizing process is 5 m or more, preferably 10 m or more. It is also preferable to use the same material as the resin-side substrate 21 or a material with a difference in Young's modulus and thermal expansion coefficient of within ±10% to prevent distortion due to temperature rise and fall of the substrate or expansion and contraction due to pressure tension during the resin curing process. (B) In the lamination process, it is preferable to stop bending the mold 1 with a roll during lamination and to laminate the mold 1 in a flat, unbent state. When laminating while flat, the meniscus cannot be used, and lamination at normal pressure will result in air entrapment, resulting in poor lamination. Therefore, lamination under reduced pressure is preferable. (C) In the pressurization process, it is preferable to uniformly pressurize the bonded mold substrate 11 and the formed substrate. In this case, the bonded mold substrate 11 and the resin-side substrate 21 can be pressurized at 0.1 MPa or more. Furthermore, if heating is performed during pressurization, it is preferable to control the rate of temperature increase to minimize the temperature difference between the mold substrate 11 and the formed substrate. In this case, the difference in thermal expansion between the mold substrate 11 and the formed substrate due to heating should be within ±10%, preferably identical. (D) In ​​the resin curing process, the molded resin 2 is cured by irradiating it with light, such as UV light. In this case, the difference in thermal expansion between the mold substrate 11 and the formed substrate due to heating should be within ±10%, preferably identical. (E) In the demolding step, the mold substrate 11 is locally curvatured to promote demolding. The thickness d of the mold substrate 11 is determined so that the curvature generates the force required for demolding, but the mold substrate 11 is not damaged.

[0089] By taking the above measures in each process, distortion within the wafer can be minimized, and deterioration of the optical properties of optical components such as waveguides can be suppressed.

[0090] In the demolding process, the relationship between the Young's modulus E and the thickness d of the mold substrate 11 that allows the mold 1 to exhibit a demolding force from the resin 2 to be molded with a slight deflection (curvature radius of 50 cm or more) is as follows:

[0091] First, the deflection of the mold substrate 11 required for demolding can be derived from Non-Patent Document 1. The equilibrium distance of formula (1) derived from the deflection h that generates the stress required for peeling the molded product from the mold 1 having the demolding energy γ (N / m) is given by E, where E is the Young's modulus of the mold substrate 11 and d is the thickness of the mold substrate 11: The radius of curvature R of the deflection h can be found from the circle that passes through the three points (0.0), (C0,h), and (-C0,h) as follows: If the minimum radius of curvature for realizing mold release with a radius of curvature that does not cause distortion of the entire wafer is Ro, the thickness d of the mold substrate 11 must satisfy the following formula (15). Experimental evaluation results show that the radius of curvature Ro should be at least 50 cm or more, and preferably 100 cm or more.

[0092] When glass with a release energy γ of 1 (N / m) and a Young's modulus E of 72 GPa is used for the mold substrate 11, the glass thickness d must be d≧0.4 mm to obtain a radius of curvature R≧50 cm, and d≧0.7 mm to obtain a radius of curvature R≧100 cm. When a resin substrate with a Young's modulus E=4 GPa is used, the resin thickness d must be d≧1.1 mm to obtain a radius of curvature R≧50 cm, and d≧2 mm to obtain a radius of curvature R≧100 cm. Incidentally, the radius of curvature for the standard nanoimprint mold substrate 11 (E=4 GPa, d=0.2 mm) is approximately 3 cm.

[0093] On the other hand, as shown in Figure 5(a), the expansion coefficient of the lower surface of the mold substrate 11 bent at a curvature R is (R + d / 2) / R, and a lateral movement Δ occurs in the pattern portion 12 during demolding. In particular, with AR waveguides with different extension directions or metalenses with high aspect ratios, if the lateral movement Δ of the pattern portion 12 is large, it can lead to damage to the transferred pattern during demolding. The magnitude of the lateral movement Δ at the radius of curvature R is as follows:

[0094] From this, it can be seen that the thicker the thickness d of the mold substrate 11, the larger the horizontal movement Δ becomes. ０ The thickness d for the following is:

[0095] Using equation (17), the magnitude of kick at the time of demolding (a) a mold 1 made of a 400 μm thick glass mold substrate 11 and (b) a mold 9 made of a resin mold substrate is shown in FIG. 9. Here, the Young's modulus of the glass mold substrate 11 is 80 GPa, the Young's modulus of the resin mold substrate is 4 GPa, and both pattern portions 12 are line and space with a height of 300 nm, a pitch of 200 nm, and a pattern width of 100 nm. The Young's modulus of the resin 2 to be molded is 4 GPa. The equilibrium distance at a height h of 300 nm is C ０ｈ＝300 Then, the magnitude of the kick during mold release is Δ / 2. Calculations show that the kick during mold release for the mold 1 made of the glass mold substrate 11 is 110 nm, while the kick for the mold 9 made of the resin mold substrate is 230 nm, meaning that the kick for the glass mold substrate 11 is reduced to about half of that for the resin mold substrate.

[0096] These tendencies can be expressed by the formula (17) of the condition for the thickness of the mold substrate 11 to have a radius of curvature larger than the radius of curvature Ro and the formula (17) of the condition for the lateral movement of the pattern portion 12 due to bending to be Δ ０ The following equation (16) is shown in FIG.

[0097] Fig. 19(a) shows the curvature radius of 50 cm or more and the lateral movement Δ ０The Young's modulus E of the mold substrate 11 and the thickness d of the mold substrate 11 must be within the range of 0.4 mm to 1.1 mm to achieve a lateral substrate displacement of the pattern portion 12 of 300 nm or less (kick Δ / 2≦150 nm) when the Young's modulus of a glass substrate is in the range of 70 to 80 GPa. It can be seen that if the lateral displacement of the pattern portion 12 is allowed to be 400 nm or less (kick Δ / 2≦200 nm), a Young's modulus E of the mold substrate 11 of just over 10 GPa can be achieved with a realistic thickness. On the other hand, if a PET substrate (4 to 5 GPa), which is the resin used for the mold substrate 11 in conventional nanoimprinting, is used as the resin for the mold substrate 11, it is found that a lateral substrate displacement of the pattern portion 12 of 400 nm or less cannot be achieved with a curvature radius of 50 cm or more.

[0098] 19(b) shows the range of the Young's modulus E of the mold substrate 11 and the thickness d of the mold substrate 11 when the radius of curvature is set to 1 cm and 2.5 cm. In order to keep the lateral movement of the pattern portion 12 to 300 nm or less (kick Δ / 2≦150 nm), the radius of curvature must be 1 cm or less and the thickness of the mold substrate 11 must be 0.1 mm or less, which shows that it is difficult to realistically achieve both a reduction in distortion and a reduction in the pattern kick.

[0099] Next, we will consider the deflection in the Z direction when pressure is applied. The length of the flat transfer section 63 between the input coupler 61 and the pupil expander, or between the input coupler 61 and the output coupler 62, is approximately 2 mm at the shortest. If we consider the deflection when a uniform pressure is applied to the flat section sandwiched between the pattern sections 12 using a doubly supported beam model as shown in Figure 20 and consider the influence of the material of the mold substrate 11, we get the following result. The deflection δ when a uniform load p is applied to a beam with width L, thickness d (m), and Young's modulus E, both ends of which are fixed, can be expressed by the following equation 18 using the doubly supported beam model: δ = 60pL ４ / (384Ed 3 )...Formula (18)

[0100] This is used to calculate the deflection of the mold 1. A uniform load of 0.1 MPa is applied to glass mold substrates 11 with a length L of 2 mm, a Young's modulus E of 72 GPa, and thicknesses d of 0.7 mm and 0.4 mm. At this time, the deflection δ of the glass mold substrate 11 with a thickness d of 0.7 mm is 10 nm, and the radius of curvature is 50 m. The deflection δ of the glass mold substrate 11 with a thickness d of 0.4 mm is 54 nm, and the radius of curvature is 9.4 m.

[0101] On the other hand, a uniform load of 0.1 MPa was applied to resin mold substrates with a length L of 2 mm, a Young's modulus E of 4 GPa, and thicknesses d of 0.4 mm and 0.2 mm. The deflection δ of the resin mold substrate with a thickness d of 0.4 mm was 976 nm, with a radius of curvature of 0.51 m. The deflection δ of the resin mold substrate with a thickness d of 0.2 mm was 7812 nm, with a radius of curvature of 0.064 m.

[0102] In an actual system, the deflection δ of liquid resin, not air, when UV curing is performed in a finite time period depends greatly on the viscosity of the resin and the process time. As will be described in the examples below, the radius of curvature of the transfer section 63 must be at least 5 m, preferably 10 m, to avoid image degradation. Therefore, while there is no problem when using the glass substrate of the present invention, when using a resin substrate mold used in conventional nanoimprinting, the deflection δ depends heavily on the viscosity of the resin and the application method.

[0103] [Example 1] 3-1 Mold Forming A manufacturing method for the mold 1 used in Example 1 will be described. First, a master mold 8 for forming the pattern portion 12 of the mold 1 is prepared. A Si substrate with a diameter of 200 mm and a thickness of 0.7 mm is used as the master mold substrate for the master mold 8. Furthermore, a mold substrate 11 for the mold 1 is made of alkali-free glass (Young's modulus 73 GPa) with a diameter of 300 mm and a thickness of 0.7 mm. A fluorine-containing UV-curable acrylic resin (Young's modulus 1.6 GPa) is used as the mold resin 120. The mold resin 120 is previously cured by UV irradiation to form the pattern portion 12 from the master mold 8. Figures 21(a) to (f) show the mold forming process using nanoimprinting.

[0104] (Introduction and evacuation) The master mold substrate and mold substrate 11 are introduced into a chamber that can be evacuated. At this time, the mold resin 120 that will become the pattern portion 12 of the mold 1 is applied in advance to the pattern surface side of the master mold 8, as shown in Figure 21 (a1), or to the surface of the mold substrate 11, as shown in Figure 21 (a2). Then, the master mold 8 and mold substrate 11 are placed opposite each other. Next, the chamber is evacuated to create a reduced pressure atmosphere of 50 Pa.

[0105] (Laminating) As shown in FIG. 21(b), the mold substrate 11 and the master mold substrate are brought close to each other while being kept parallel to each other, and are laminated together with the mold resin 120 interposed therebetween.

[0106] (Pressure application) The air pressure around the bonded mold substrate 11 and master mold substrate is increased to 0.5 MPa, whereupon the mold resin 120 fills the pattern portion of the master mold 8, as shown in FIG.

[0107] (UV Curing) As shown in FIG. 21(d), the molding resin 120 is irradiated with UV light of 365 nm to cure the molding resin 120.

[0108] (Mold Release) As shown in Figures 21(e) and (f), in order to control the height h required for the bending required for mold release at a constant value, the mold 1 is released from the master mold 8 using a release device (see Patent No. 6377956) that suctions the cross section into an S-shape. The release energy γ between the master mold 8 and the hardened mold resin 120 is 0.5 N / m to 1.5 N / m. When the radius of curvature R of the mold 1 is R≦(3Ed ３ / 64γ) 0.5Since release begins when the mold bends, when the release energy γ is 0.5 N / m, the radius of curvature is 1.53 m. Furthermore, when the release energy γ is 1.5 N / m, the radius of curvature is 0.88 m. This radius of curvature is several tens of times larger than the radius of curvature of 2.8 cm required for release with the same release energy from a standard resin (PET) substrate (Young's modulus 4 GPa, thickness 0.188 mm). To prevent distortion, a radius of curvature of 50 cm or more is required, and the thickness of the mold substrate 11 must be 0.4 mm or more, which is met by this condition.

[0109] 3-2 Molding of Resin-Side Substrate 21 Next, we will explain the method of transferring a pattern to the resin 2 to be molded using the above-mentioned mold 1. The resin-side substrate 21 was made of alkali-free glass (Young's modulus 73 GPa) with a diameter of 200 mm and a thickness of 0.7 mm. The resin 2 to be molded was made of UV-cured acrylic resin (Young's modulus 3 GPa). Figures 21(g) to (l) show the molding process of the resin 2 to be molded by nanoimprinting.

[0110] (Introduction and evacuation) The mold substrate 11 and the resin-side substrate 21 coated with the molded resin 2 are introduced into a chamber that can be evacuated. As shown in Figure 21(g), with the surfaces of the mold substrate 11 and the resin-side substrate 21 coated with the molded resin 2 facing each other, the chamber is evacuated to create a reduced-pressure atmosphere of 50 Pa.

[0111] (Laminating) As shown in FIG. 21(h), the mold substrate 11 and the resin-side substrate 21 are brought close together while being kept parallel to each other, and are laminated together with the resin 2 to be molded interposed therebetween.

[0112] (Pressure application) The air pressure around the bonded mold substrate 11 and resin side substrate 21 is increased to 0.5 MPa, whereupon the resin to be molded 2 fills the pattern portion 12 of the mold 1, as shown in FIG.

[0113] (UV curing) As shown in FIG. 21(j), the moldable resin 2 is irradiated with UV light of 365 nm to cure the moldable resin 2.

[0114] (Mold Release) As shown in Figures 21(k) and (l), in order to control the height h required for the bending required for mold release at a constant value, the mold 1 is released from the resin 2 to be molded using a peeling device (see Patent No. 6377956) that sucks the cross section into an S-shape. The release energy γ between the mold 1 and the hardened resin 2 to be molded is 0.5 N / m to 1.5 N / m. When the radius of curvature R of the mold 1 is R≦(3Ed ３ / 64γ) 0.5 Since release begins when the mold bends, when the release energy γ is 0.5 N / m, the radius of curvature is 1.53 m. Furthermore, when the release energy γ is 1.5 N / m, the radius of curvature is 0.88 m. This radius of curvature is several tens of times larger than the radius of curvature of 2.8 cm required for release with the same release energy from a standard resin (PET) substrate (Young's modulus 4 GPa, thickness 0.188 mm). To prevent distortion, a radius of curvature of 50 cm or more is required, and the thickness of the mold substrate 11 must be 0.4 mm or more, which is met by this condition.

[0115] The peeling device does not necessarily have to be the one described above, and any device can be used as long as it can peel the mold 1 by moving the S-shaped cross section while increasing the area that lifts the mold 1 from the end of the mold 1, and can release the mold while maintaining the radius of curvature of the mold substrate 11 at 50 cm or more, preferably 1 m or more.

[0116] Example 2 The distribution of distortion within a wafer due to nanoimprinting using the same process as in Example 1 was evaluated using the same method as in Non-Patent Document 2. A mold 1 shown in FIG. 22(b) was created by the method described in Example 1 from a master mold 8 shown in FIG. 22(a), which was manufactured using photolithography and dry etching. Furthermore, as shown in FIG. 22(c), a pattern 22 was transferred from the mold 1 to a resin 2 to be molded on a resin-side substrate 21 (wafer). The pattern 22 included box-in-box inner marks 23, which are typically used for overlay exposure, at the corners of each chip.

[0117] Next, as shown in Figure 22(d), a pattern is formed on the molded resin 2 by photolithography. The wafer is aligned using cross marks at two locations and then exposed and developed to form a box-in-box outer mark 24. The distortion within the wafer is calculated from the positions of the in and out box patterns at each location.

[0118] The measurement results are shown in Figure 23. Figure 23(a) shows the strain distribution within the wafer for the fourth molding pattern made continuously using the same mold, and Figure 23(b) shows the average strain distribution for 16 moldings made using the same mold. It can be seen that the magnitude of the strain was a maximum of 0.5 μm within the wafer, which is less than one-tenth of that obtained using a conventional resin mold.

[0119] Figures 23(c) and 23(d) show the measurement of distortion at each point on the wafer for patterns molded from the same mold from the first to the 25th imprint, and it was confirmed that there was almost no change with the number of imprints. This is also very small compared to the distortion that fluctuates by about two times with the number of imprints with a conventional resin mold.

[0120] The results of small distortion and little variation as described above indicate that this method is extremely advantageous in reducing the variation in performance between products when molding AR glass at the wafer level.

[0121] [Example 3] In order to widen the viewing angle of the AR waveguide, it is necessary to use a high refractive index material with a refractive index of 1.9 to 2.0 for the substrate. Here, the thermal expansion coefficient of high refractive index materials is about 7 to 8 ppm / °C, while the alkali-free glass used for the mold substrate 11 has a coefficient of about 3 ppm / °C. Therefore, there is a risk of distortion due to the difference in thermal expansion coefficient caused by temperature changes during processing.

[0122] In this case, a high refractive index material may be used for the mold substrate 11. Alternatively, other glasses may be used as long as their thermal expansion coefficient differs by no more than 10% from that of the resin-side substrate 21. Optical glasses such as BK7 glass can have their thermal expansion coefficient adjusted to 7 to 9 ppm / °C by adjusting their composition, and their Young's modulus is approximately the same as that of alkali-free glass. Furthermore, glass wafers with a size of 200 mm to 300 mm are commercially available, and these can be used for the mold substrate 11.

[0123] Furthermore, AR waveguides require not only a high refractive index for the substrate but also for the resin to widen the viewing angle. Currently, high-refractive-index resins containing TiO2 or ZrO2 nanoparticles (fillers) with a refractive index of up to approximately 1.9 are commercially available, but materials with a refractive index of over 2.0 are needed. Increasing the refractive index requires either increasing the filler content or increasing the refractive index of the resin itself. In either case, however, the viscosity of the resin increases, making it more difficult to fill the mold's pattern area 12. Future high-performance waveguides will require the use of these high-viscosity materials, and while progress is being made in reducing viscosity on the material side, process measures are also needed.

[0124] Regarding resin viscosity and temperature, the Williams-Landell-Ferry model indicates that the viscosity of molten polymers decreases with increasing temperature. For example, raising a resin with a glass transition temperature of -20°C to 40°C reduces its viscosity to approximately one-tenth of that at 20°C, improving nanoimprint moldability. However, a 20°C increase in temperature causes a 16 μm radius expansion for a 200 mm wafer, while the radius expansion for alkali-free glass is only 6 μm. This difference of 10 μm causes distortion. On the other hand, a glass wafer with a thermal expansion coefficient of 7.2 ppm / °C expands to 14.4 μm, a difference of 1.6 μm compared to a high-refractive-index wafer, reducing distortion. Furthermore, the rate of temperature rise must be controlled to prevent the temperature difference between the mold substrate 11 and the resin substrate 21 from widening during heating.

[0125] Thermal conductivity of glass (high refractive index glass: 0.8 to 1 Wm -1 K -1 ) it can be calculated that when heating one side of the bonded glass sheets, each 0.7 mm thick, at a temperature rise rate of 1°C / sec or less, the temperature difference between the mold substrate 11 and the resin side substrate 21 can be kept to 1°C or less.

[0126] FIG. 24 shows an example of molding a high refractive index, wide viewing angle waveguide. The mold substrate 11 is made of N-BK7 glass (Young's modulus 82 GPa, thermal expansion coefficient 7.1 ppm / °C, thermal conductivity 1.13 W / m) with a diameter of 200 mm and a thickness of 0.7 mm. -1 K-1 The resin-side substrate 21 is made of high refractive index glass HOYA TAFD40-W (Young's modulus 121 GPa, thermal expansion coefficient 7.2 ppm / °C, thermal conductivity 0.9 W / m -1 K -1 ) was used. The molding resin was a fluorine-containing UV-cured acrylic resin (Young's modulus 1.6 GPa). The resin to be molded 2 was a UV-cured acrylic resin with a high refractive index (Young's modulus 10 GPa).

[0127] 24(a), in a chamber that can be evacuated, the pattern surface of the mold substrate 11 (the surface on which the pattern portion 12 is located) is placed opposite the surface of the resin-side substrate 21 on which the resin to be molded 2 is applied.The chamber is then evacuated to create a reduced-pressure atmosphere of 50 Pa.

[0128] (Laminating) As shown in FIG. 24(b), the mold substrate 11 and the resin-side substrate 21 are brought close together while being kept parallel to each other, and are laminated together with the resin 2 to be molded interposed therebetween.

[0129] (Pressurization and temperature increase) The air pressure around the bonded mold substrate 11 and resin side substrate 21 is increased to 0.9 MPa. At this time, the temperatures of the mold substrate 11 and resin side substrate 21 are increased at a rate of 1°C / sec or less to 40°C. Then, as shown in Figure 24(c), the molded resin 2 is filled into the pattern portion 12 of the mold 1.

[0130] (UV curing) As shown in FIG. 24(d), the moldable resin 2 is irradiated with UV light of 365 nm to cure the moldable resin 2.

[0131] (Mold Release) As shown in Figures 24(e) and (f), in order to control the height h required for the bending required for mold release at a constant value, the mold 1 is released from the molding resin using a peeling device (see Patent No. 6377956) that suctions the cross section in an S-shape. The release energy γ between the mold 1 and the hardened resin 2 is 0.5 N / m to 1.5 N / m. The radius of curvature R of the mold 1 is R≦(3Ed ３ / 64γ) 0.5 Since release begins at the point where it bends below this, when the release energy γ is 0.5 N / m, the radius of curvature is 1.62 m. When the release energy γ is 1.5 N / m, the radius of curvature is 0.963 m.

[0132] Example 4: This example demonstrates the effect on images when the pattern of the AR glass waveguide 6 is molded using a mold substrate 11 made of glass and a mold made of resin. Since it is not practical to create an actual sample to compare the effect of deflection on the image, a virtual experiment was conducted to compare simulated images. In the simulation, a 2 mm square test pattern image was input and reflected and diffracted, as shown in Figure 25. This image was transferred 2 mm inside the glass by repeated 45° reflections. It was then output as a 2 mm square image by further reflection and diffraction. The resolution of the transferred image was compared using a ray tracing simulation. The glass used had a refractive index of 1.7 and a thickness of 0.4 mm. Figure 26 shows a comparison of the results of simulating the resolution of the output image using models with different radii of curvature on the surface of the transfer section 63.

[0133] At a curvature radius of 50 m, which corresponds to the bending of glass with a Young's modulus of 72 GPa and a thickness of 0.7 mm, as shown in Figure 26(a), although brightness decreases, it can be seen that up to the g mark can be resolved, just like the input image. On the other hand, at a curvature radius of 3 m, as shown in Figure 26(b), the g mark cannot be resolved, and the limit for modification is the F mark. Furthermore, at a curvature radius of 2 m, as shown in Figure 26(c), the resolvable mark has deteriorated to the e mark. Therefore, a realistic radius of curvature for the surface of the transfer section 63 of the waveguide is at least 5 m, preferably 10 m or more, and more preferably 50 m or more.

[0134] [Example 5] Figure 27 shows the characteristics when the surface of the transfer section 63 is deformed convexly upward. When the shape of the in-coupler is circular as shown in Figure 27(a), the thickness of the resin in the transfer section 63 becomes convex in the direction perpendicular to the transfer direction because the amount of resin extruded from the pattern section 12 differs between the center and the periphery. In this type of shape, the distortion caused by transfer has almost no effect on the resolution at a curvature radius of 50 m as shown in Figure 27(b). However, at a curvature radius of 2 m as shown in Figure 27(c), it can be seen that the resolution is significantly degraded due to concave distortion in the transfer direction.

[0135] Example 6: A comparison was made between a glass substrate mold having a pattern portion 12 on the surface of a glass mold substrate 11 and a resin substrate mold having a pattern portion 12 on the surface of a resin mold substrate 11, in which highly difficult patterns were molded. The glass mold substrate 11 was a 0.5 mm thick, alkali-free glass substrate (Young's modulus 73.6 GPa). The resin mold substrate 11 was a 0.2 mm thick, PET (polyethylene terephthalate) resin substrate (Young's modulus 4 GPa). The pattern portion 12 was a metalens pattern made of an acrylic molding resin transferred from a master mold 8 formed of Si. The metalens pattern consisted of pillars of different diameters, with a square pillar pitch of 620 nm, a pillar height of 1.4 μm, an aspect ratio of the thinnest pillar of 7, and a metalens diameter of 2 mm.

[0136] (Glass Substrate Mold) An acrylic molding resin was spin-coated onto a master mold 8 made of Si coated with a fluoroalkyl mold release promoter. The alkali-free glass substrate was then pressed against the master mold 8 in a vacuum atmosphere, and the molding resin was then cured by UV irradiation. The acrylic resin had a viscosity of 1 to 3 GPa after curing. The glass substrate was vacuum-suctioned from the edge, raised to a release height h of 50 μm to 100 μm, and bent in an S-shape, starting the mold release from the edge. The glass substrate mold 1 was then peeled off from the master mold 8 by successively increasing the area of ​​suction.

[0137] The glass substrate mold 1 was used to perform imprinting on a resin 2 to be molded. The resin 2 was an acrylic high-refractive index resin containing TiO2 nanofillers and having a refractive index of 1.9. First, the resin 2 to be molded was spin-coated onto a 4-inch inorganic alkali glass. Next, the chamber was evacuated with the coated surface of the resin 2 facing the patterned surface of the glass substrate mold 1, and the coated surface of the resin 2 to be molded and the patterned surface of the glass substrate mold 1 were brought into contact under a reduced pressure of 50 Pa. Next, the resin 2 to be molded was cured by UV irradiation.

[0138] The demolding energy between the molding resin and the non-patterned resin surface of the molded resin 2 was measured in advance and found to be 0.9 N / m. In this example, the patterned area was only 2 mm in diameter within a 4-inch diameter glass wafer, so the demolding energy was considered to be almost the same as that of a non-patterned surface. Since the slit pitch of the demolding device was 3 mm, the equilibrium distance C ０ The mold release was performed by setting the rise height H (twice the length of h) of the mold substrate 11 to about 100 μm.

[0139] (Resin Substrate Mold) An acrylic molding resin was spin-coated onto a master mold 8 made of Si coated with a fluoroalkyl mold release promoter, and the PET resin substrate was pressed against it in a vacuum atmosphere. The molding resin was then cured by UV irradiation. The PET resin substrate was then lifted from its edge to separate the resin substrate mold from the master mold 8.

[0140] The resin substrate mold was used to imprint on the resin 2 to be molded. The resin 2 was an acrylic high-refractive index resin with a refractive index of 1.9 containing TiO2 nanofillers. First, the resin 2 to be molded was spin-coated onto a 4-inch inorganic alkali glass. Next, the chamber was evacuated with the coated surface of the resin 2 facing the patterned surface of the resin substrate mold, and the coated surface of the resin 2 to be molded and the patterned surface of the resin substrate mold were brought into contact under a reduced pressure of 50 Pa. Next, the resin 2 to be molded was hardened by UV irradiation. Finally, the resin substrate was lifted from the edge, and the resin substrate mold was peeled off from the resin 2 to be molded.

[0141] (Comparison) Figure 28 shows a comparison of the demolding between a glass substrate mold and a resin substrate mold. In the sample molded using the resin substrate mold, collapse of the pillar pattern was observed over a wide area, as shown in Figures 28(b1) to (b3). In particular, it can be seen that there was a lot of pattern damage in the latter half of the demolding process when viewed from the demolding direction. On the other hand, in the case of the glass substrate mold, good molding was confirmed, with almost no pillar damage observed, as shown in Figures 28(a1) to (a3).

[0142] [Example 7] This example shows a case where a tilted grating pattern is formed on a wafer with a diameter of 200 mm using a mold made of glass as the mold substrate 11. This is intended for application to an AR glass waveguide.

[0143] (Glass Substrate Mold) The mold was made of alkali-free glass (Young's modulus 73.6 GPa) with a diameter of 300 mm and a thickness of 0.775 mm. The pattern portion 12 consisted of four 20 mm x 30 mm square inclined gratings with a pitch of 350 nm, a height of 250 nm, and an inclination angle of 60°. As shown in Figure 29(a), the extension directions of the four inclined gratings were 0° and 90°, respectively. Furthermore, for each azimuth angle pattern, the grating inclination angles were -60° and 60°. An acrylic molding resin was used as the resin for the pattern portion 12.

[0144] (Resin Side Substrate 21) A Si wafer having a diameter of 200 mm and a thickness of 0.725 mm was used as the resin side substrate 21. The surface of the resin side substrate 21 was spin-coated with an acrylic UV-curable resin as the resin 2 to be molded.

[0145] After the moldable resin 2 on the resin-side substrate 21 and the glass substrate mold were bonded together in a vacuum atmosphere, a pressure of 0.1 MPa was applied, and the moldable resin 2 was filled into the pattern portion 12. Next, the moldable resin 2 was irradiated with UV light of 365 nm to harden the moldable resin 2.

[0146] (Mold release conditions) A peeling device was used for demolding, which allows the demolding to proceed while gradually expanding the suction area by moving a piston (see Patent No. 6377956). The peeling device also had vacuum suction slits with a width of 2 mm and a pitch of 3 mm. The pressure inside the chamber during demolding was atmospheric pressure (95 kPa) + 60 kPa, and the glass was sucked in at a pressure difference with the vacuum of 155 kPa. The demolding speed was 2 mm / s.

[0147] (Results) The SEM photograph of the molding results is shown in Figure 29(b), which shows that the tilted gratings in different directions were all molded well.

[0148] REFERENCE SIGNS LIST 1 mold 2 resin to be molded 3 bonding surface 5 suction slit 6 AR glass wave guide 8 master mold 11 mold substrate 12 pattern portion 13 curved portion 14 outer edge portion 15 front side 16 back side 21 resin side substrate 22 transfer pattern 25 end of resin side substrate 31 end of bonding surface 61 input coupler 62 output coupler 63 transfer portion 81 master mold substrate 120 molded resin

Claims

1. A mold release method for releasing a mold having a pattern portion from a resin to be molded from the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more, the method comprising: forming a curved portion having a curvature that generates a bending moment capable of peeling the mold and the molded article on the mold substrate, and moving the curved portion along the bonding surface of the mold and the resin to be molded.

2. The mold release method according to claim 1, wherein the curved portion is formed at the end portion at the start of the mold release in order to cause a crack at the end portion of the bonding surface between the mold and the resin to be molded.

3. The end portion of the mold substrate is bonded so as to have an outer edge portion protruding outside the end portion of the resin-side substrate that holds the resin to be molded on the surface, and in order to generate a bending moment that causes a crack at the end portion, a differential pressure p due to gas is applied to the front surface side and the back surface side of the mold substrate at at least a part of the outer edge portion to form the curved portion. The mold release method according to claim 2.

4. The distance L at which the mold substrate receives the differential pressure p is the distance C from the differential pressure application position of the mold substrate at the differential pressure p to the resin-side substrate end when the bending energy of the mold substrate at the differential pressure p and the surface energy generated by the cleavage are in equilibrium. ｐ The mold release method according to claim 3, characterized in that it is as described above.

5. When the Young's modulus of the glass is E, the thickness of the mold substrate is d, and the surface energy is γ, The mold release method according to claim 4, characterized in that it satisfies 6. The surface energy γ is 1.5 N or less, the differential pressure p is 0.2 MPa or less, and the mold release method according to claim 5, characterized in that L≧4.6 + 8(d - 0.4) / 1.1 is satisfied.

7. When the Young's modulus of the glass is E, the thickness of the mold substrate is d, the surface energy is γ, and the fracture stress of the glass is Mc, d ≧ 21Eγ / Mc ２ The mold release method according to claim 4, characterized in that it is as described above.

8. The mold release method according to claim 7, characterized in that the thickness of the mold substrate is 0.3 mm or more.

9. The back surface of the mold substrate is partially sucked from the end portion and lifted to a height H, and deformed so that the cross section of the curved portion becomes S-shaped. The curvature of the curved portion is such that the bending energy accumulated in the mold substrate at the contact surface with the resin to be molded is released and the surface energy generated by the resulting crack between the mold and the resin to be molded are in equilibrium under quasi-static conditions. The mold release method according to claim 1, characterized in that the region for sucking the back surface of the mold substrate is sequentially expanded from the end portion to expand the portion of the height H, and the mold and the resin to be molded are released.

10. A mechanism for expanding the area for sequentially sucking the back surface of the mold substrate from the end is provided by suction slits that are periodically arranged and sequentially switched to vacuum exhaust. Let E be the Young's modulus of the glass, d be the thickness of the mold substrate, γ be the surface energy, Pi be the pitch of the suction slits, h be half of the maximum height H of the mold substrate due to suction, and C be the distance between the position on the resin surface where the height of the mold substrate becomes h and the end of the bonding surface between the mold and the resin to be molded. ０ Then, the height h satisfies the following formula The mold release method according to claim 9, characterized in that it satisfies the above.

11. An imprint method for bonding a mold having a pattern portion on the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more to a resin to be molded and transferring a fine structure by the pattern portion, characterized in that the mold release method according to any one of claims 1 to 10 is used when releasing the mold from the resin to be molded.

12. A method for manufacturing a waveguide, comprising bonding a mold having a pattern portion on the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more to a resin to be molded, and transferring a fine structure as a waveguide by the pattern portion, wherein when the mold is released from the resin to be molded, the release method according to any one of claims 1 to 10 is used.

13. The method for manufacturing a waveguide according to claim 12, wherein the waveguide is a waveguide for AR.

14. A method for manufacturing a metalens, comprising bonding a mold having a pattern portion on the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more to a resin to be molded, and transferring a fine structure as a metalens by the pattern portion, wherein when the mold is released from the resin to be molded, the release method according to any one of claims 1 to 10 is used.

15. An imprint method for transferring a fine structure by bonding a mold having a pattern portion on the surface of a mold substrate made of glass or a resin having a Young's modulus of 10 GPa or more to a resin to be molded, the method comprising: a bonding step of opposing the pattern portion side of the mold substrate to the resin side of a resin-side substrate that holds the resin to be molded on its surface and bonding them under reduced pressure; a pressurizing step of pressurizing the bonded mold substrate and the resin-side substrate at 0.1 MPa or more; a resin curing step of irradiating light to the resin to be molded after the pressurizing step to cure it; and a release step of forming a curved portion having a curvature that generates a bending moment capable of peeling the mold and the resin to be molded on the mold substrate and moving the curved portion along the bonding surface of the mold and the resin to be molded.

16. The imprint method according to claim 15, wherein in the release step, the radius of curvature locally applied to the curved portion of the mold substrate is 50 cm or more.

17. When the minimum radius of curvature given by the mold is Ro (= 50 cm), the release energy between the mold and the resin to be molded is γ, and the Young's modulus of the mold substrate is E, the thickness d of the mold substrate satisfies The imprint method according to claim 16, characterized in that it satisfies 18. Let the upper limit of the lateral movement amount of the replica pattern during release be Δ ０ Then, the imprint method according to claim 16, wherein the thickness d of the mold substrate satisfies ​ 19. The upper limit Δ of the amount of movement ０ The imprinting method according to claim 18, wherein is 300 m or less.

20. The mold has a flat portion sandwiched between the pattern portions, and the pressurizing step is characterized in that the radius of curvature of the surface of the flat portion during pressurization is 5 m or more.

21. The imprinting method according to claim 17, wherein in the pressing step, the temperatures of the mold substrate and the resin-side substrate are raised when pressing.

22. The imprinting method according to claim 21, wherein the rate of temperature rise is 1 °C / second or less.

23. The imprinting method according to any one of claims 15 to 19, wherein the mold substrate has the same coefficient of thermal expansion as the resin-side substrate or a coefficient of thermal expansion within ±10% of that of the resin-side substrate.

24. The imprinting method according to any one of claims 15 to 20, wherein the mold substrate is a high refractive index glass having a refractive index of 1.9 or more, and the mold substrate is a glass having a coefficient of thermal expansion of 7 ppm / °C or more.

25. A method for manufacturing an optical component, characterized in that a waveguide or a metalens is manufactured by the imprinting method according to any one of claims 15 to 22.

26. A wafer of 200 mm or more on which an optical component composed of a pattern of a plurality of AR waveguides or metalenses before dicing is mounted, wherein the distortion of the pattern of each mounted optical component within the wafer is 1 μm or less.

27. A waveguide device for AR glass, wherein the radius of curvature of the surface of the light transfer portion without a pattern located between any one of an input coupler and an output coupler, an input coupler and a pupil-expanding diffraction grating, or a pupil-expanding diffraction grating and an output coupler is 5 m or more.

Images