JP7466375B2 - Imprinting method, imprinting apparatus and method for manufacturing article - Google Patents

Description

The present invention relates to an imprinting method, an imprinting apparatus, and a method for manufacturing an article.

Imprinting technology is a microfabrication technology in which droplets of an imprinting material are placed on an adhesive film formed on a substrate, and the imprinting material is brought into contact with a mold to form a pattern of the imprinting material on the substrate that corresponds to the fine pattern formed on the mold. With imprinting technology, it is possible to form fine structures on the order of a few nanometers on a substrate.

In imprint technology, one of the methods for hardening the imprint material is the photocuring method. The photocuring method involves hardening the imprint material placed on a substrate by irradiating it with light such as ultraviolet light while it is in contact with a mold, and then separating the mold from the hardened imprint material to form a pattern of the imprint material on the substrate.

In the photocuring method, light leaking from a shot area on a substrate (leakage light) may reach (be irradiated with) an adhesion film formed in a shot area where no pattern is formed. When the adhesion film is irradiated with light, the surface condition of the adhesion film changes, and the size of the droplets of imprint material placed there changes. Because the amount of irradiation with the leakage light differs depending on the position within the shot area, the size of the droplets of imprint material placed within the shot area becomes non-uniform.

If the size of the imprint material droplets becomes non-uniform, the droplets of imprint material may spread unevenly within the shot area or in each shot area on the substrate, causing the imprint material to overflow beyond the shot area. In such cases, the imprint material may adhere to the edges of the pattern area of the mold, or the imprint material may not be sufficiently filled into the pattern (recesses) of the mold, resulting in unfilled defects in the pattern formed on the substrate.

Therefore, a technology has been proposed to prevent the imprint material from spilling out beyond the shot area (see Patent Document 1). Patent Document 1 discloses a technology in which light is irradiated around (the entire circumference of) the shot area on the substrate to make the adhesive film on the substrate liquid-repellent to the imprint material, thereby making it difficult for the droplets of the imprint material to wet and spread out.

JP 2018-92996 A

However, Patent Document 1 does not specifically disclose the light intensity distribution of the light irradiated around the shot area on the substrate. For example, if light with the same intensity is irradiated around the shot area on the substrate, the liquid repellency of the adhesive film on the substrate will be uniform and the same, resulting in a distribution in the liquid repellency of the adhesive film between areas in the shot area that are reached by the leaked light and areas that are not reached by the leaked light. Furthermore, Patent Document 1 does not disclose anything about leaked light, and does not take any measures to deal with leaked light.

The present invention has been made in consideration of the problems with the conventional technology, and has as an example objective the provision of a technology that is advantageous for making the size of droplets of imprint material placed on a substrate uniform.

In order to achieve the above-mentioned object, an imprinting method as one aspect of the present invention is an imprinting method for forming a pattern of an imprint material in each of a plurality of shot areas on a substrate using a mold, the method comprising: a first step of forming a film on the substrate, the film having a function of bringing the substrate and the imprint material into close contact with each other and the liquid repellency to the imprint material is increased by irradiation with a first light; a second step of irradiating the film formed on the substrate with the first light after the first step so as to reduce a difference in size of droplets of the imprint material arranged in each shot area on the substrate, the difference being caused by irradiation with leakage light of a second light for hardening the imprint material that leaks outside each shot area on the substrate and stray light caused by the leakage light being repeatedly reflected between the mold and the substrate; and a third step of arranging droplets of the imprint material on the film after the second step, and irradiating the film with the second light while the droplets of the imprint material are in contact with the mold, thereby forming the pattern.

Further objects and other aspects of the present invention will become apparent from the embodiments described below with reference to the accompanying drawings.

The present invention can provide a technology that is advantageous for, for example, making the size of droplets of imprint material placed on a substrate uniform.

1 is a schematic diagram showing a configuration of an imprint apparatus according to one aspect of the present invention. 4 is a flowchart for explaining an imprint method in the first embodiment. 1 is a schematic cross-sectional view showing a droplet of imprint material disposed on an adhesion layer. FIG. 2 is a diagram showing an arrangement of a plurality of shot areas on a substrate. 1A-1C are diagrams showing the state before and after contact between the imprint material on the substrate and the pattern area of the mold. 11A and 11B are diagrams for explaining the influence of leak light on an unprocessed shot area. FIG. 3 is a diagram for explaining step S02 shown in FIG. 2 . 11 is a diagram showing an example of a relationship between the irradiation time of light from an irradiation unit and the amount of change in size of droplets of an imprint material. FIG. FIG. 2 is a schematic diagram showing an example of the configuration of an irradiation unit. 10 is a flowchart for explaining an imprint method in a second embodiment. 1A to 1C are diagrams for explaining a method for manufacturing an article.

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations are omitted.

Figure 1 is a schematic diagram showing the configuration of an imprinting apparatus 1 according to one aspect of the present invention. The imprinting apparatus 1 is a lithography apparatus employed in a lithography process, which is a manufacturing process for devices such as semiconductor elements, liquid crystal display elements, and magnetic storage media as articles, for forming a pattern on a substrate. The imprinting apparatus 1 brings an imprinting material supplied onto the substrate into contact with a mold, and applies energy for curing to the imprinting material to form a pattern of a cured product to which the pattern of the mold has been transferred. The mold is also called a mold, template, or original plate.

As the imprint material, a material (curable composition) that hardens when hardening energy is applied is used. The hardening energy may be electromagnetic waves or heat. Electromagnetic waves include, for example, light having a wavelength selected from the range of 10 nm or more and 1 mm or less, specifically infrared rays, visible light, ultraviolet rays, etc.

A curable composition is a composition that is cured by irradiation with light or by heating. A photocurable composition that is cured by irradiation with light contains at least a polymerizable compound and a photopolymerization initiator, and may further contain a non-polymerizable compound or a solvent, as necessary. The non-polymerizable compound is at least one selected from the group consisting of sensitizers, hydrogen donors, internal mold release agents, surfactants, antioxidants, polymer components, etc.

The imprint material may be applied in the form of a film on the substrate by a spin coater or a slit coater. The imprint material may also be applied in the form of droplets, or in the form of islands or a film formed by connecting multiple droplets, by a liquid ejection head. The viscosity of the imprint material (viscosity at 25°C) is, for example, 1 mPa·s or more and 100 mPa·s or less.

The substrate may be made of glass, ceramics, metal, semiconductor, resin, etc., and if necessary, a member made of a material other than the substrate may be formed on the surface. Specifically, the substrate may be a silicon wafer, a compound semiconductor wafer, quartz glass, etc.

In this embodiment, the imprinting apparatus 1 employs a photocuring method as a method for curing the imprinting material. As shown in FIG. 1, the imprinting apparatus 1 has a mold holding unit 3 that holds and moves a mold 8, a substrate holding unit 4 that holds and moves a substrate 10, and a dispenser 5 that places droplets of the imprinting material on the substrate. The imprinting apparatus 1 also has a curing unit 2 that irradiates light (second light) 9 that hardens the imprinting material, an imaging unit 6 that images the contact state between the imprinting material on the substrate and the mold 8, and a detection unit 7 that detects marks provided on the mold 8 and the substrate 10. The imprinting apparatus 1 further has an irradiation unit 20 that irradiates light (first light) 35, and a control unit 21.

In this specification and the accompanying drawings, directions are shown in an XYZ coordinate system in which the direction parallel to the surface of the substrate 10 is the XY plane. The directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are the X direction, Y direction, and Z direction, respectively, and the rotation around the X-axis, the rotation around the Y-axis, and the rotation around the Z-axis are θX, θY, and θZ, respectively. Control or drive (movement) about the X-axis, Y-axis, and Z-axis means control or drive (movement) about the direction parallel to the X-axis, the direction parallel to the Y-axis, and the direction parallel to the Z-axis, respectively. In addition, control or drive about the θX-axis, θY-axis, and θZ-axis means control or drive about the rotation around the axis parallel to the X-axis, the rotation around the axis parallel to the Y-axis, and the rotation around the axis parallel to the Z-axis, respectively.

The substrate holding unit 4 includes a substrate chuck 16 that holds the substrate 10, and a substrate driving mechanism 17 that drives the substrate chuck 16 (controls the position of the substrate 10) in at least two axes, the X-axis direction and the Y-axis direction. The substrate holding unit 4 is provided with a plurality of reference mirrors 18 on its side corresponding to the X, Y, Z, θX, θY, and θZ directions. In addition, a plurality of laser interferometers (length measuring devices) 19 that irradiate each reference mirror 18 with a beam to measure the position of the substrate holding unit 4 are provided for each of the plurality of reference mirrors 18. The positioning of the substrate 10 (substrate holding unit 4) is performed based on the position of the substrate holding unit 4 measured by the laser interferometer 19 under the control of the control unit 21. Note that instead of the reference mirror 18 and the laser interferometer 19, an encoder may be used to measure the position of the substrate holding unit 4.

The mold holding unit 3 includes a mold chuck 11 that holds the mold 8, and a mold driving mechanism 38 that drives the mold chuck 11 about at least one axis in the Z-axis direction (controlling the position of the mold 8 in the vertical direction (Z-axis direction)). The mold driving mechanism 38 drives the mold chuck 11 downward (-Z direction) to bring the pattern area 8a of the mold 8 held by the mold chuck 11 into contact with the imprint material 14 on the substrate (imprinting). The mold driving mechanism 38 drives the mold chuck 11 upward (+Z direction) to separate the mold 8 from the hardened imprint material 14 on the substrate (release). Note that in the imprinting and release, instead of driving the mold chuck 11, the substrate chuck 16 may be driven in the vertical direction, or the mold chuck 11 and the substrate chuck 16 may be driven relatively.

In this embodiment, the pattern area 8a of the mold 8 has a pattern that is an inversion of the pattern (concave and recess) to be formed on the substrate. The pattern area 8a of the mold 8 is formed in a portion that protrudes toward the substrate when held by the mold chuck 11, a portion known as a mesa. The pattern area 8a of the mold 8 can be replaced with a flat surface (flat portion) on which no pattern is formed.

The mold holding unit 3 may be provided with a space (cavity) 13 defined by the mold 8 and a light-transmitting member 41 made of, for example, a quartz plate. By adjusting the pressure in this space 13, it is possible to deform the mold 8 during imprinting and demolding. For example, by increasing the pressure in the space 13 during imprinting, the pattern area 8a and the imprint material 14 can be brought into contact with each other while the mold 8 is deformed into a convex shape relative to the substrate 10.

The detection unit 7 detects the mark provided on the mold 8 and the mark provided on the substrate 10. Based on the detection result of the detection unit 7, the control unit 21 determines the relative position (positional deviation) between the mold 8 and the substrate 10, and can align the mold 8 and the substrate 10 by moving at least one of the mold 8 and the substrate 10.

The control unit 21 may be provided inside the imprinting device 1, or may be provided at a location separate from the imprinting device 1. The control unit 21 is composed of an information processing device (computer) including a CPU, a memory, etc., and controls the entire imprinting device 1 according to a program stored in the storage unit. The control unit 21 controls each part of the imprinting device 1 to function as a processing unit that performs an imprinting process that forms a pattern of an imprinting material in each of a plurality of shot areas on a substrate. In the imprinting process, the imprinting material 14 is placed on the substrate, and the imprinting material 14 is hardened while the mold 8 is in contact with the imprinting material 14. Then, the gap between the mold 8 and the substrate 10 is widened, and the mold 8 is separated from the hardened imprinting material 14 on the substrate, thereby transferring the pattern of the mold 8 to the imprinting material 14 on the substrate. This series of processes is performed for each of a plurality of shot areas on the substrate. Therefore, when performing an imprinting process for each of a plurality of shot areas on one substrate, the imprinting process is repeated as many times as the number of the plurality of shot areas on the substrate.

First Embodiment
The imprint method according to the first embodiment of the present invention will be described with reference to Fig. 2. In S01 (first step), before droplets of imprint material 14 are placed in one shot area (target shot area) on the substrate that is to be subjected to imprint processing, an adhesion film is formed (applied) on the substrate (the entire substrate 10). The adhesion film may be formed on the substrate by an external device such as a coating device, or may be formed on the substrate within the imprint apparatus 1 by providing a coating device in the imprint apparatus.

In S02 (second step), before placing droplets of imprint material 14 in the target shot area on the substrate, light 35 from the irradiation unit 20 is irradiated onto the adhesion film on the target shot area.

In S03 (third step), droplets of imprint material 14 are placed on the adhesion film irradiated with light 35 in S02, and light 9 is irradiated from the curing unit 2 while the droplets of imprint material 14 are in contact with the mold 8 to form a pattern of the imprint material 14 (imprint processing).

In S04, it is determined whether the target shot area in which the pattern of imprint material 14 is formed is the final shot area. If the target shot area is the final shot area, the process ends. On the other hand, if the target shot area is not the final shot area, the next shot area is set as the target shot area and the process proceeds to S02. In this manner, S02 and S03 are repeated until the target shot area in which the pattern of imprint material 14 is formed in S03 becomes the final shot area.

The step S01 shown in FIG. 2 will be described. The adhesive film formed on the substrate has the function of adhering the substrate 10 and the imprint material 14 to each other. Such an adhesive film has a liquid-philic property with respect to the imprint material 14, but when irradiated with light having a wavelength of, for example, 450 nm or less, it changes from being liquid-philic to being liquid-repellent with respect to the imprint material 14, i.e., it has the property of increasing the liquid-repellent property with respect to the imprint material 14.

The mechanism by which the adhesion film becomes hydrophilic to the imprint material 14 when irradiated with light has not been elucidated, but the inventors speculate as follows. When moisture in the atmosphere is adsorbed to the surface of the adhesion film, the surface energy increases. When the adhesion film in this state is irradiated with light, the moisture adsorbed on the surface is desorbed, and the surface energy decreases compared to before the light irradiation, which is thought to cause the adhesion film to become hydrophobic to the imprint material 14.

Here, we will explain typical examples of adhesion films (components thereof), but the adhesion film is not limited to the materials listed below. Adhesion films are also disclosed in, for example, JP-T-2009-503139, JP-A-2014-189616, and JP-A-2014-3123.

As the material for the adhesive film, a poly(meth)acrylate compound having an ethylenically unsaturated group and a hydrophilic group is preferable. Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, and a (meth)acryloyl group. Specifically, examples of the ethylenically unsaturated group include methyl (meth)acrylate and ethyl (meth)acrylate. Examples of the hydrophilic group include an alcoholic hydroxyl group, a carboxyl group, a phenolic hydroxyl group, and an ether group. The poly(meth)acrylate compound (acrylic resin) contains an ethylenically unsaturated group and a hydrophilic group, and the ethylenically unsaturated group and the hydrophilic group may be contained in the same repeating unit or may be contained in different repeating units.

The material of the adhesive film is preferably an organic solvent containing a volatile solvent and having at least one of an ester structure, a ketone structure, a hydroxyl group, and an ether structure. The material of the adhesive film may contain a crosslinking agent, a thermal polymerization initiator, and a surfactant as other components. As the crosslinking agent, a cationic polymerizable compound such as an epoxy compound, an oxetane compound, a methylol compound, a methylol ether compound, or a vinyl ether compound is preferable. As the thermal polymerization initiator, for example, an azo compound or an organic peroxide can be mentioned. As the surfactant, a nonionic surfactant is preferable, and it is preferable that it is a fluorine-based, a Si-based, or a fluorine-Si-based.

3(a) and 3(b) are schematic cross-sectional views showing droplets of the imprint material 14 arranged on an adhesive film 102 formed on a substrate. Referring to FIG. 3(a) and FIG. 3(b), an adhesive film 102 is formed on a substrate 10, and droplets of the imprint material 14 are arranged on the adhesive film 102. FIG. 3(a) shows a case where droplets of the imprint material 14 are arranged on an adhesive film 102 that is not irradiated with light. Referring to FIG. 3(a), since the imprint material 14 and the adhesive film 102 are hydrophilic, the droplets of the imprint material 14 come into contact with the adhesive film 102 at a low contact angle and are in a wet and spread state. FIG. 3(b) shows a case where droplets of the imprint material 14 are arranged on an adhesive film 102 that is irradiated with light. Referring to FIG. 3(b), since the adhesive film 102 is changed from hydrophilic to liquid repellent by the irradiation of light, the contact angle of the droplets of the imprint material 14 increases, making it difficult to wet and spread.

The step S02 shown in Figure 2 will be explained. Figures 4(a) and 4(b) are diagrams showing an arrangement of multiple shot areas on a substrate. With reference to Figures 4(a) and 4(b), 201 indicates a shot area that has not been subjected to imprint processing (unprocessed shot area). Also, 202 indicates a shot area (target shot area) where imprint processing will be performed, and 203 indicates a shot area where imprint processing has been performed (processed shot area).

Figure 5(a) shows the state before the imprint material 14 on the substrate and the pattern area 8a of the mold 8 are brought into contact. As shown in Figure 5(a), an adhesive film 102 is formed on the substrate 10, and droplets of the imprint material 14 are disposed on the adhesive film 102. Figure 5(b) shows the state after the imprint material 14 on the substrate and the pattern area 8a of the mold 8 are brought into contact, that is, the state in which the pattern area 8a of the mold 8 spreads the droplets of the imprint material 14. As shown in Figure 5(b), the light 9 emitted from the curing unit 2 (light source) is irradiated to the imprint material 14, and the imprint material 14 is cured. At this time, the light 9 is irradiated to a range wider than the shot area 305 where the imprint material 14 is disposed. Here, the light leaking outside the shot area 305 is referred to as the leaked light 307, and the range irradiated (reached) by the leaked light 307 is referred to as the leaked light range 306. Furthermore, the leaked light 307 becomes stray light 304 that is repeatedly reflected between the mold 8 and the substrate 10, and reaches an area farther away than the leaked light range 306.

As shown in FIG. 6A, the leakage light 307 affects the unprocessed shot region 201 where imprint processing has not been performed. When the leakage light 307 reaches the unprocessed shot region 201, as described above, the property of the adhesion film 102 formed in the unprocessed shot region 201 with respect to the imprint material 14 changes from liquid-philic to liquid-repellent. Therefore, in the unprocessed shot region 201, it becomes difficult for the droplets of the imprint material 14 to wet and spread.

Figure 6 (b) shows a schematic diagram of the imprint processing being performed on four shot areas SR1, SR2, SR3, and SR4 on the substrate in the order of shot area SR1, shot area SR2, shot area SR3, and shot area SR4. The shot areas SR1, SR2, and SR3 are processed shot areas where imprint processing has been performed, and the shot area SR4 is the target shot area where imprint processing will be performed from now on. Referring to Figure 6 (b), in the corners of the shot areas SR1, SR2, and SR3, the leakage light 307 (leakage light range 306) overlaps multiple times, so the influence of the leakage light 307 becomes larger in proportion to the number of times the leakage light 307 is irradiated. Specifically, in the shot area SR4, the liquid repellency of the adhesion film 102 is greater in the corner portion 306a where the leakage light 307 overlaps multiple times than in the corner portion 306b where the leakage light 307 does not reach. Therefore, compared to corner portion 306b of shot region SR4, droplets of imprint material 14 are less likely to wet and spread in corner portion 306a of shot region SR4, making defects such as unfilled defects more likely to occur.

Furthermore, leakage light 307 also has an effect on shot areas distant from the shot area adjacent to the shot area where imprint processing was performed. Specifically, as shown in FIG. 5B, leakage light 307 is repeatedly reflected between mold 8 and substrate 10 and becomes stray light 304, which reaches more distant shot areas and changes the wettability of such shot areas. If imprint processing is performed only on one shot area, the effects of leakage light 307 and stray light 304 are minor. However, if imprint processing is continued on multiple shot areas, the later the shot area where imprint processing is performed, the greater the accumulation of leakage light 307 and stray light 304 due to the previous imprint processing, and the greater the effect.

In this way, the influence of the leakage light 307 on the shot area on the substrate differs depending on the order in which the imprint process is performed. For example, as shown by the arrow 204 in FIG. 4A, consider a case in which the imprint process is performed in one direction on a plurality of shot areas on the substrate. Specifically, consider a case in which the imprint process starts from the shot area at the lower right end, and when the imprint process on the shot area at the lower left end is completed, the imprint process is resumed from the shot area at the right end of the next row (line). In this case, the shot area on the left side of the substrate 10 is more influenced by the leakage light 307 and the stray light 304 than the shot area on the right side of the substrate 10. Note that if the order in which the imprint process is performed is reversed, the influence of the leakage light 307 and the stray light 304 is greater on the shot area on the right side of the substrate 10 than on the shot area on the left side of the substrate 10. Also, if the imprint process is performed on the shot areas on the substrate in two directions (round trip) instead of one direction (one way), the range of influence of the leakage light 307 and the stray light 304 differs between the outward and return paths.

In this embodiment, the influence of the leakage light 307 and the stray light 304 is acquired (confirmed) before performing the imprint process. Specifically, a substrate on which an adhesive film 102 is formed is prepared, droplets of the imprint material 14 are placed on the substrate, and the imprint material 14 is hardened in the droplet state by irradiating the imprint material 14 with light 9 without contacting the mold 8 (by bringing the mold 8 close to the substrate). Then, the size of the droplets of the hardened imprint material 14 on the substrate is measured while repeating the placement and hardening of the droplets of the imprint material 14 in all shot areas on the substrate in the same order as in the actual imprint process. For example, the size of the droplets of the imprint material 14 may be measured using the imaging unit 6 of the imprint device 1, or the substrate may be removed from the imprint device 1 and the size of the droplets of the imprint material 14 may be measured using an external optical microscope, SEM, or the like.

It is also preferable to measure the size of all droplets of imprint material 14 within the shot area on the substrate. However, the size of the droplets of imprint material 14 may be measured by sampling for each area within the shot area on the substrate. The number of measurements to be made for measuring the size of the droplets of imprint material 14 is arbitrary. However, if the number of measurements is too small, it becomes difficult to grasp the range of influence of the leakage light 307 and stray light 304, so it is preferable to adjust (set) the number of measurements so that the range of influence of the leakage light 307 and stray light 304 can be grasped.

The size of the droplets of the imprint material 14 may be measured (evaluated) as an absolute value or as a relative value. For example, the size of the droplets of the imprint material 14 in the first shot area, which is not affected by the leakage light 307 and stray light 304, may be used as a reference, and the sizes of the droplets at the same position in the other shot areas may be evaluated relatively.

In this embodiment, the range affected by leakage light 307 and stray light 304 can be estimated and obtained from the size of the droplets of imprint material 14 measured in this manner.

7A is a diagram showing the size of droplets of imprint material 14 arranged in each shot area on the substrate. In FIG. 7A, the size of the droplets of imprint material 14 in each of the shot areas 401, 402, and 403 on the substrate, specifically, the size of the droplets of imprint material 14 at five representative locations, namely, four corners and one central location of each shot area, is shown numerically. In this embodiment, the size of the droplets of imprint material 14 is shown in five stages, with "1" being the smallest and "5" being the largest. The order of imprint processing is, as shown by the arrow 204 in FIG. 7A, unidirectional, starting from the shot area at the bottom right end, and returning to the shot area at the right end of the next row (row) after the shot area at the bottom left end is completed.

7A, the shot area 401 is the first shot area to be imprinted, and is therefore not affected by the leakage light 307 (and stray light 304). Therefore, in the shot area 401, all droplet sizes of the imprint material 14 are the maximum "5". The shot area 402 is a shot area near the center of the substrate 10, and is therefore slightly affected by the leakage light 307 and stray light 304 from the previous imprint processes. Therefore, the droplet size of the imprint material 14 at the lower right corner of the shot area 402 is "2". On the other hand, the droplet size of the imprint material 14 at the upper left corner of the shot area 402, which is not directly affected by the leakage light 307, is "4". The shot area 403 is the last shot area to be imprinted, and is therefore heavily (accumulated) affected by the leakage light 307 and stray light 304 from the previous imprint processes. Therefore, the droplet size of the imprint material 14 at the lower right corner of the shot area 403 is the minimum "1". Furthermore, the size of the droplets of the imprint material 14 in the center and the upper left and upper right corners of the shot area 403 is "2", and the size of the droplets of the imprint material 14 in the upper left corner of the shot area 403, where the influence of the leakage light 307 and stray light 304 is small, is "3". In this way, the size of the droplets of the imprint material 14 is small in areas where the influence of the leakage light 307 and stray light 304 is large, and the size of the droplets of the imprint material 14 is large in areas where the influence of the leakage light 307 and stray light 304 is small.

Therefore, in this embodiment, in S02, the light 35 from the irradiation unit 20 is irradiated onto the adhesion film 102 formed in each shot area on the substrate. Specifically, the light 35 from the irradiation unit 20 is irradiated onto the adhesion film 102 so that the difference in size of the droplets of the imprint material 14 placed in each shot area (each of the multiple positions on the substrate) caused by irradiation with the leakage light 307 and the stray light 304 (light 9) is reduced. At this time, it is preferable to irradiate the adhesion film 102 with the light 35 from the irradiation unit 20 so that the difference in size of the droplets of the imprint material 14 falls within an allowable range. It is further preferable to irradiate the adhesion film 102 with the light 35 from the irradiation unit 20 so that the droplets of the imprint material 14 are the same size. Therefore, the light 35 having an intensity distribution within the substrate or shot area is irradiated onto the adhesion film 102 as the light 35 from the irradiation unit 20. Thus, S02 is a process in which light 35 having an intensity distribution is irradiated within the substrate or shot area, making the adhesion film 102 formed within the area irradiated with light 35 liquid repellent and forming a distribution in the liquid repellency.

Now, referring to Figs. 7(b), 7(b) and 7(c), the control of the intensity distribution of the light 35 irradiated to each of the shot regions 401, 402 and 403 on the substrate will be described. In this embodiment, the intensity distribution of the light 35 is controlled so that the size of the smallest droplet of the imprint material 14 in the shot region 403 where the last imprint process is performed is the same as the size of the droplets of the imprint material 14 in the other shot regions. Figs. 7(b) to 7(d) show how the intensity distribution of the light 35 irradiated to each shot region on the substrate is changed. In this embodiment, the intensity of the light 35 irradiated from the irradiation unit 20 is expressed in five stages, with "0" being the weakest and "4" being the strongest.

Figure 7 (b) shows the size of the droplets of the imprint material 14 in the shot area 401, the intensity of the light 35 irradiated to the adhesive film 102 formed in the shot area 401, and the size of the droplets of the imprint material 14 in the shot area 401 after irradiation with the light 35. As described above, in the shot area 401, there is no difference in the size of the droplets of the imprint material 14, and the size is also the largest. Therefore, the light 35 having no intensity distribution and the strongest intensity "4" is irradiated from the irradiation unit 20 to the shot area 401 (the adhesive film 102 formed therein). As a result, when the droplets of the imprint material 14 are placed in the shot area 401 after irradiation with the light 35, the size becomes "1".

7(c) shows the size of the droplets of the imprint material 14 in the shot area 402, the intensity of the light 35 irradiated to the adhesive film 102 formed in the shot area 402, and the size of the droplets of the imprint material 14 in the shot area 402 after irradiation with the light 35. In the shot area 402, the size of the droplets of the imprint material 14 varies. Therefore, the light 35 having an intensity distribution is irradiated from the irradiation unit 20 to the shot area 402 (the adhesive film 102 formed therein). Specifically, the light 35 having an intensity of "1" is irradiated from the irradiation unit 20 to the lower right corner of the shot area 402 (where the size of the droplets of the imprint material 14 is small). On the other hand, the light 35 having an intensity of "3" is irradiated from the irradiation unit 20 to the upper left corner of the shot area 402 (where the size of the droplets of the imprint material 14 is large). In addition, the center, upper right, and lower left corners of the shot area 402 are irradiated with light 35 having an intensity of "2" from the irradiation unit 20. As a result, when a droplet of the imprint material 14 is placed in the shot area 402 after being irradiated with light 35, its size becomes "1."

7(d) shows the size of the droplets of the imprint material 14 in the shot area 403, the intensity of the light 35 irradiated to the adhesive film 102 formed in the shot area 403, and the size of the droplets of the imprint material 14 in the shot area 403 after irradiation with the light 35. In the shot area 403, there is a difference in the size of the droplets of the imprint material 14. Therefore, the light 35 having an intensity distribution is irradiated from the irradiation unit 20 to the shot area 403 (the adhesive film 102 formed therein). Specifically, the light 35 having an intensity "0" is irradiated from the irradiation unit 20 to the lower right corner of the shot area 403 (where the droplet size of the imprint material 14 is small). On the other hand, the light 35 having an intensity "2" is irradiated from the irradiation unit 20 to the upper left corner of the shot area 403 (where the droplet size of the imprint material 14 is large). In addition, the central portion, upper right corner portion, and lower left corner portion of the shot area 403 are irradiated with light 35 having an intensity of "1" from the irradiation unit 20. As a result, when a droplet of the imprint material 14 is placed in the shot area 403 after being irradiated with light 35, its size becomes "1".

In this manner, in this embodiment, before placing the imprint material 14 on the substrate, the intensity distribution of the light 35 irradiated to the adhesion film 102 is controlled so that the size of the droplets of the imprint material 14 in each shot area is the same. This makes it possible to make the size of the droplets of the imprint material 14 uniform within the substrate when the droplets of the imprint material 14 are placed on the substrate. Note that when light 35 having only a distribution is irradiated within the shot area, as shown in FIG. 7(a), the size of the droplets of the imprint material 14 differs at each position within the shot area, so that the size of the droplets of the imprint material 14 cannot be made uniform. It is necessary to irradiate the light 35 while controlling not only the distribution but also the intensity in each shot area on the substrate.

It is preferable to obtain (confirm) in advance the amount of change in the size of the droplets of the imprint material 14 on the substrate relative to the irradiation time and amount of light of the light 35 irradiated from the irradiation unit 20 to the adhesive film 102. The relationship between the irradiation time and amount of light of the light 35 from the irradiation unit 20 and the amount of change in the size of the droplets of the imprint material 14 on the substrate varies depending on the type of imprint material 14 and the type of adhesive film 102. Therefore, it is necessary to obtain, through experiments, the relationship between the irradiation time and amount of light of the light 35 from the irradiation unit 20 and the amount of change in the size of the droplets of the imprint material 14 on the substrate for each type of imprint material 14 and each type of adhesive film 102.

Figure 8 is a diagram showing an example of the relationship between the irradiation time of light 35 from the irradiation unit 20 and the change in size of the droplets of the imprint material 14 on the substrate. In Figure 8, the vertical axis shows the irradiation time of light 35 irradiated from the irradiation unit 20 to the adhesion film 102, and the horizontal axis shows the area reduction rate of the droplets of the imprint material 14. The area reduction rate of the droplets of the imprint material 14 is one of the indicators of the liquid repellency state of the adhesion film 102 with respect to the imprint material 14, that is, the change in the size of the droplets of the imprint material 14. Note that in Figure 8, the area reduction rate of the droplets of the imprint material 14 is shown relative to the size (area) of the droplets of the imprint material 14 when the adhesion film 102 is not irradiated with light 35 from the irradiation unit 20, which is 100%. Also, here, the adhesion film 102 formed on the substrate is irradiated with uniform light 35 within the shot area while changing the irradiation time, and then the droplets of the imprint material 14 are arranged and cured, and the size of the droplets is measured. Referring to Figure 8, it can be seen that the size (area) of the droplets of the imprint material 14 decreases as the irradiation time of the light 35 increases. By acquiring such a relationship, it is possible to control the intensity distribution of the light 35 irradiated from the irradiation unit 20 to the adhesion film 102 so that the size of the droplets of the imprint material 14 in each shot area is the same.

With reference to FIG. 9, an example of the configuration of the irradiation unit 20 that allows the intensity distribution of the light 35 irradiated to each shot area on the substrate to be changed will be described. The irradiation unit 20 includes a light source 302, an optical element 504a, a light modulation element (spatial light modulation element) 503, and an optical element 504b.

The light source 302 is composed of a light source that can obtain the optical output required to change the property of the adhesive film 102 formed on the substrate from lyophilic to lyophobic, and is composed of, for example, a lamp, a laser diode, an LED, etc. The light 35 from the light source 302 is guided to the light modulation element 503 via the optical element 504a. In this embodiment, the light modulation element 503 is composed of a digital micromirror device (DMD). However, the light modulation element 503 is not limited to a DMD, and may be composed of other elements such as an LCD device or an LCOS device. The light modulation element 503 is disposed between the light source 302 and the substrate 10, and can arbitrarily set the irradiation area where the light 35 is irradiated to the substrate 10 and the intensity of the light 35, i.e., the intensity distribution of the light 35, under the control of the control unit 21. The magnification of the light 35, whose irradiation area and intensity are controlled by the light modulation element 503, projected onto the adhesive film 102 formed on the substrate is adjusted via the optical element 504b.

In this embodiment, in addition to the curing unit 2 that irradiates light 9 to harden the imprint material 14, an irradiation unit 20 that irradiates light 35 to the adhesion film 102 is provided (i.e., light 9 and light 35 are lights emitted from different light sources). However, light 9 from the curing unit 2 may be irradiated to the adhesion film 102 (i.e., light 9 and light 35 may be lights emitted from the same light source). Furthermore, light 9 and light 35 may have different wavelengths from each other or the same wavelength within the range in which they each have the function to be realized.

In addition, in this embodiment, it is preferable to satisfy the following conditions when irradiating the adhesion film 102 with light 35 from the irradiation unit 20 so that the difference in droplet size of the imprint material 14 falls within an acceptable range.

For example, the light 35 irradiated from the irradiation unit 20 to the adhesive film 102 is controlled in intensity within a range in which the imprint material 14 is not too liquid-repellent. If the liquid-repellency of the adhesive film 102 becomes too high, the droplets of the imprint material 14 will not wet and spread sufficiently, and unfilled defects will easily occur. In order to suppress such unfilled defects, it is necessary to lengthen the contact time during which the imprint material 14 on the substrate is in contact with the mold 8. However, if the contact time during which the imprint material 14 on the substrate is in contact with the mold 8 is lengthened, productivity will decrease, and this is not practical. On the other hand, if the light 35 is irradiated until the liquid-repellency of the adhesive film 102 is saturated, the droplets of the imprint material 14 will be difficult to bond with each other, and therefore unfilled defects will occur even if the contact time during which the imprint material 14 on the substrate is in contact with the mold 8 is lengthened. In this case, it is necessary to change the arrangement pattern of the droplets of the imprint material 14 on the substrate to reduce the spacing between the droplets, but reducing the spacing between the droplets increases the droplet density, and the film thickness (residual film thickness) of the pattern of the imprint material 14 formed on the substrate increases.

Furthermore, if the area of the droplets of imprint material 14 on the substrate decreases, the coverage of the (droplets of) imprint material 14 in each shot area will decrease. Although the size of one droplet of imprint material 14 is minute, 30,000 to 60,000 droplets are placed in one shot area, so the impact on the entire shot area is large. For example, if light 35 is irradiated until the liquid repellency of the adhesion film 102 is saturated, the coverage of the droplets relative to the area of the shot area will abnormally decrease by about 10% over the entire shot area, which may result in unfilled defects.

The relationship between the liquid repellency (liquid repellency state) of the adhesive film 102 and the unfilled defects varies (differs) depending on the type of imprint material 14, the type of adhesive film 102, the pattern of the mold 8, and the arrangement pattern of the droplets of the imprint material 14. It is preferable to control the liquid repellency of the adhesive film 102 within a range in which the filling state of the imprint material 14 relative to the pattern of the mold 8 can be adjusted during the contact time during which the imprint material 14 on the substrate is in contact with the mold 8. For example, it is preferable to suppress the reduction rate of the coverage area of the droplets of the imprint material 14 in terms of the area ratio of the shot area to less than 10%, and more preferably to suppress it to 5% or less. However, such values are only examples, and it is preferable to determine the optimal numerical range according to various conditions of the imprint processing actually performed. The coverage area is the ratio of the area of the shot area to the area (total) of all the droplets of the imprint material 14 arranged in the shot area. The coverage area when the adhesion film 102 is not irradiated with light 35 (when the size of the droplets of imprint material 14 is the largest) is taken as 100%, and the reduction in the area of the droplets of imprint material 14 when the adhesion film 102 is irradiated with light 35 is taken as the reduction rate of the coverage area.

Next, the step S03 shown in FIG. 2 will be described. In S02, a distribution of the lyophilicity and lyophobicity of the adhesive film 102 is formed by irradiating each shot area on the substrate with light 35 having an intensity distribution suitable for each shot area from the irradiation unit 20. By disposing droplets of the imprint material 14 on such an adhesive film 102, the size of the droplets of the imprint material 14 can be made uniform. This allows the imprint process to be performed under the same conditions for all shot areas on the substrate. In other words, a common droplet disposition pattern (drop recipe) of the imprint material 14 can be used for all shot areas on the substrate.

The advantages of making the droplet size of the imprint material 14 the same among the multiple shot areas on the substrate as in this embodiment are as follows. If the droplet size of the imprint material 14 is not made the same among the multiple shot areas on the substrate, the state of wetting and spreading of the droplets of the imprint material 14 will differ between the shot area where the imprint process is performed first and the shot area where the imprint process is performed last. If the arrangement pattern is optimized for the shot area where the imprint process is performed first, the droplets of the imprint material 14 will not easily spread in the shot area where the imprint process is performed last. Therefore, unfilled defects are likely to occur in the shot area where the imprint process is performed last. On the other hand, if the arrangement pattern is optimized for the shot area where the imprint process is performed last, the droplets of the imprint material 14 will easily spread in the shot area where the imprint process is performed first. Therefore, in the shot area where the imprint process is performed first, the imprint material 14 will easily extend beyond the shot area. It is possible to optimize the arrangement pattern for each shot area on the substrate, but optimizing the arrangement pattern for all shot areas is very time-consuming. Furthermore, if the order of imprint processes is changed or the amount of droplets of the imprint material 14 discharged from the dispenser 5 is changed, the arrangement pattern must be re-optimized each time, which is not practical. With this embodiment, as described above, it is possible to use a common arrangement pattern of droplets of the imprint material 14 in all shot areas on the substrate.

In addition, in this embodiment, the droplet size of the imprint material 14 is made uniform across multiple shot areas on the substrate, but this is not limited to this. For example, making the droplet size of the imprint material 14 uniform in each of multiple shot areas on the substrate also constitutes one aspect of the present invention.

Second Embodiment
An imprint method according to a second embodiment of the present invention will be described with reference to Fig. 10. In the first embodiment, before performing the imprint process on a shot area on a substrate, the light 35 is irradiated from the irradiation unit 20 onto the adhesion film 102 formed on the shot area (i.e., S02 and S03 are performed for each shot area on the substrate 10). In the present embodiment, before performing the imprint process on each shot area on the substrate, the light 35 is irradiated from the irradiation unit 20 onto the adhesion film 102 formed on the substrate (i.e., the light 35 is irradiated collectively onto all of the multiple shot areas on the substrate).

In this embodiment, compared to the first embodiment, step S02 is replaced with step S22. As in the first embodiment, in this embodiment, the size of the droplets of imprint material 14 to be placed in each shot area on the substrate is measured in advance, and the intensity distribution of light 35 to be irradiated to each shot area is determined. In S22, light 35 is irradiated from the irradiation unit 20 to the adhesion film 102 formed on the substrate, i.e., to all of the multiple shot areas on the substrate, with an intensity distribution suitable for each shot area.

In S22, the order in which the light 35 is irradiated to each shot area on the substrate is not limited, and may be, for example, the order of the imprint process or another order. Furthermore, if it is possible to irradiate each shot area on the substrate with light 35 having a desired intensity distribution, it is not necessary to irradiate each shot area with light 35, and light 35 may be irradiated to multiple shot areas at once. For example, light 35 may be irradiated to 2×2 or 3×3 shot areas on the substrate using multiple light modulation elements 503, or light 35 may be irradiated to all shot areas on the substrate at once.

In this embodiment, even if the adhesion film 102 formed on the substrate 10 is irradiated with (uniform) light 35 having no intensity distribution all at once, it is not possible to make the droplets of the imprint material 14 the same size. In addition, it is necessary to accurately align and irradiate each shot area on the substrate with light 35 having an intensity distribution suitable for each shot area. If there is a misalignment between each shot area on the substrate and the light 35 having an intensity distribution suitable for each shot area, it becomes impossible to control the size of the droplets of the imprint material 14 in the misaligned area.

Third Embodiment
In the first and second embodiments, the liquid repellent treatment is performed by irradiating the adhesion film 102 formed on the substrate with light 35 in the imprint apparatus 1, but the present invention is not limited to this. In this embodiment, a case where the liquid repellent treatment of the adhesion film 102 is performed outside the imprint apparatus 1 will be described.

The process of irradiating the light 35 to the adhesion film 102 formed on the substrate 10 does not necessarily have to be performed by the imprinting apparatus 1. For example, a device for irradiating the light 35 may be provided on a transport device that transports the substrate 10 between the imprinting apparatus 1 and the outside. However, the device for irradiating the light 35 needs to accurately align and irradiate each shot area on the substrate with the light 35 having an intensity distribution suitable for each shot area. If there is a misalignment between each shot area on the substrate and the light 35 having an intensity distribution suitable for each shot area, it becomes impossible to control the size of the droplets of the imprinting material 14 in the misaligned area.

Fourth Embodiment
The pattern of the cured material formed by using the imprint apparatus 1 is used permanently on at least a part of various articles, or temporarily when manufacturing various articles. The articles include electric circuit elements, optical elements, MEMS, recording elements, sensors, and molds. Examples of the electric circuit elements include volatile or non-volatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, and semiconductor elements such as LSI, CCD, image sensor, and FPGA. Examples of the mold include a mold for imprinting.

The pattern of the cured material is used as is as at least a part of the component of the above-mentioned article, or is used temporarily as a resist mask. After etching or ion implantation is performed in the substrate processing step, the resist mask is removed.

Next, a specific method for manufacturing the article will be described. As shown in FIG. 11(a), a substrate such as a silicon wafer is prepared with a workpiece such as an insulator formed on its surface, and then an imprinting material is applied to the surface of the workpiece by an inkjet method or the like. Here, the imprinting material in the form of multiple droplets is shown applied to the substrate.

As shown in FIG. 11(b), the imprinting mold is placed with the side on which the concave-convex pattern is formed facing the imprinting material on the substrate. As shown in FIG. 11(c), the substrate on which the imprinting material has been applied is brought into contact with the mold, and pressure is applied. The imprinting material fills the gap between the mold and the workpiece. When light is irradiated through the mold in this state as hardening energy, the imprinting material hardens.

As shown in FIG. 11(d), after the imprint material has hardened, the mold and substrate are separated, forming a pattern of the cured imprint material on the substrate. This cured material pattern has a shape in which the concave portions of the mold correspond to the convex portions of the cured material, and the convex portions of the mold correspond to the concave portions of the cured material, i.e., the concave and convex pattern of the mold is transferred to the imprint material.

As shown in FIG. 11(e), when etching is performed using the pattern of the cured material as an etching-resistant mask, the portions of the surface of the workpiece where there is no cured material or where only a thin layer remains are removed, forming grooves. As shown in FIG. 11(f), when the pattern of the cured material is removed, an article with grooves formed on the surface of the workpiece can be obtained. Here, the pattern of the cured material is removed, but it may also be used as an interlayer insulating film contained in a semiconductor element, i.e., a component of an article, without being removed after processing.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

1: Imprinting device 8: Mold 10: Substrate 14: Imprinting material 20: Irradiation unit 102: Adhesion film

Claims (14)

An imprinting method for forming a pattern of an imprint material in each of a plurality of shot areas on a substrate using a mold, the method comprising:
a first step of forming a film on the substrate, the film having a function of bringing the substrate and the imprint material into close contact with each other, the film increasing in liquid repellency with respect to the imprint material by irradiation with a first light;
a second step of irradiating the film formed on the substrate with the first light after the first step so as to reduce a difference in size of droplets of the imprint material disposed in each shot area on the substrate, the difference being caused by irradiation of leakage light leaking outside each shot area on the substrate and stray light resulting from repeated reflection of the leakage light between the mold and the substrate, among second light for hardening the imprint material on the film;
a third step of forming the pattern by disposing droplets of the imprint material on the film after the second step and irradiating the second light with the droplets of the imprint material in contact with the mold;
1. An imprint method comprising the steps of: The imprinting method according to claim 1, characterized in that in the second step, the first light is irradiated onto the film so that the difference in size of the droplets of the imprint material placed in each shot area on the substrate falls within an acceptable range. The imprinting method according to claim 2, wherein in the second step, the first light is irradiated onto the film so that the size of the droplets of the imprint material placed in each shot area on the substrate is the same. The imprinting method according to any one of claims 1 to 3, characterized in that in the second step, the first light having an intensity distribution within the substrate is irradiated onto the film. The imprinting method according to claim 2, characterized in that in the second step, the first light is irradiated onto the film so that the difference in size of the droplets of the imprint material between the multiple shot areas falls within the tolerance range. The imprinting method according to claim 2, characterized in that in the second step, the first light is irradiated onto the film so that the difference in size of the droplets of the imprinting material in each of the multiple shot areas falls within the tolerance range. 7. The imprint method according to claim 1, wherein the second step and the third step are performed for each shot area of the substrate . The imprint method according to claim 1 , wherein the second step is performed collectively on the plurality of shot regions. The imprinting method according to any one of claims 1 to 8, characterized in that the first light and the second light are emitted from different light sources. The imprinting method according to claim 9, characterized in that the first light and the second light have different wavelengths. The imprinting method according to any one of claims 1 to 8, characterized in that the first light and the second light are emitted from the same light source. An imprint apparatus for forming a pattern of an imprint material in each of a plurality of shot areas on a substrate using a mold,
a dispenser that has a function of bringing the substrate and the imprint material into close contact with each other, and that places droplets of the imprint material on the substrate on which a film that increases the liquid repellency of the imprint material by irradiation with a first light is formed;
an irradiation unit that irradiates the film with the first light so as to reduce a difference in size of droplets of the imprint material to be disposed in each shot area on the substrate, the difference being caused by irradiation of the film with leakage light that leaks outside each shot area on the substrate and stray light caused by the leakage light being repeatedly reflected between the mold and the substrate, which is part of a second light that hardens the imprint material, before the dispenser places droplets of the imprint material on the substrate;
An imprint apparatus comprising: The imprinting apparatus according to claim 12, further comprising a processing unit that performs a process of forming the pattern by disposing droplets of the imprinting material on the film using the dispenser after the irradiation unit irradiates the film with the first light, and irradiating the droplets of the imprinting material with a second light while the droplets are in contact with the mold. forming a pattern on a substrate using the imprint apparatus according to claim 12 or 13;
processing the substrate on which the pattern has been formed in the process;
producing an article from the processed substrate;
A method for producing an article, comprising the steps of:

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