Patent ID: 12221340

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to accompanying drawings and examples.

First Embodiment

Referring toFIGS.1A and1B, a configuration of an imprint apparatus according to a first embodiment will be described.FIGS.1A and1Billustrate a configuration of the imprint apparatus according to the first embodiment. In imprint processing performed by the imprint apparatus according to the first embodiment, an imprint material (resin)3is supplied to a substrate2held by a substrate stage1through prior application or the like of the imprint material3to the entire surface of the substrate (supply process). Then, a patterned portion of a mold4with a desired uneven pattern configured thereon is brought into contact with the imprint material3. After the contact, the imprint material is irradiated with light with a predetermined wavelength to harden the imprint material (hardening process), and the pattern is formed on the imprint material3in a predetermined pattern region (transfer shot region) on the substrate2(contact process). Thereafter, the mold4is separated from the hardened imprint material3. In this manner, the three-dimensional pattern (uneven pattern) formed on the mold4is formed on the substrate2. Note that the light with the predetermined wavelength is, for example, ultraviolet light10. Note that the imprint material3may be hardened using heat in the hardening process.

The imprint apparatus according to the first embodiment includes a substrate stage1configured to hold the substrate2, an imprint head (support element)5configured to hold the mold4, a detector8, and a control unit11.

The substrate stage1holds and moves the substrate2using a vacuum adsorption force or an electrostatic force, for example. The substrate stage1can be moved by a drive mechanism (not illustrated) such as a linear motor or a piezoelectric actuator, for example. The drive mechanism may include a fine drive system for finely moving the substrate stage1and a rough drive system for moving the substrate stage1by a larger amount of movement than that of the fine drive system. The substrate stage1positions, for example, a shot region, on which imprint processing is to be performed, immediately below a supply unit (not illustrated) by holding the substrate2and moving the substrate2in an XY plane. Also, the substrate stage1positions the mold4and the substrate2in the direction of the XY plane when the mold4and the imprint material3on the substrate are brought into contact with each other. Note that the moving direction of the substrate stage1is not limited thereto and the substrate stage1may be configured to move in the X-axis direction, the Y-axis direction, the Z-axis direction, and rotation directions around the axes.

The substrate2is a substrate to which the imprint material3has been applied and has a predetermined mark (substrate mark7) for positioning the mold4for forming a pattern relative to a predetermined pattern region on the substrate2in the imprint apparatus. In the first embodiment, the viscosity of the imprint material3at a predetermined position, which includes the position of the substrate mark7, other than the pattern region is set to be higher than the viscosity of the imprint material in the pattern region on the substrate2.

The imprint head5holds and moves the mold4using a vacuum adsorption force or an electrostatic force, for example. The imprint head5includes a drive mechanism such as a linear motor or an air cylinder, for example, and is configured to be able to drive the mold4. Also, the detector8configured to detect a relative positional relationship between a mold mark6formed on the mold4and having an uneven pattern and the substrate mark7formed on the substrate2by optically observing moire or the like generated when the mold mark6and the substrate mark7face each other is disposed inside the imprint head5.

The control unit11is connected to configuration members related to imprint processing such as the substrate stage1, the imprint head5, and the supply unit using a wired or wireless communication line to control operations of these configuration members. The control unit11includes a memory that stores a computer program for controlling various operations and further includes a CPU configured to execute the computer program. Note that the control unit11also functions as a control section.

In a case in which it is difficult to configure the detector8in the narrow space inside the imprint head5as inFIG.1A, images of the mold mark6and the substrate mark7may be formed upward using an image forming optical system9, and the images may be observed as inFIG.1B.

The imprint material3has a property of being hardened by light with a predetermined wavelength, for example, ultraviolet light10, when the imprint processing is performed, and being hardened when illuminated (irradiated) with the ultraviolet light10from above the apparatus. As inFIG.1B, an optical element21as illustrated inFIG.9, which will be described later, may be configured inside the image forming optical system9to synthesize an optical path. In this case, it is only necessary to cause the optical element21to have a property of reflecting light with the wavelength of the ultraviolet light10and transmitting light with the wavelength of the detector8. Note that the light with the wavelength of the ultraviolet light10may be transmitted and the light with the wavelength of the detector8may be reflected depending on an apparatus configuration.

FIG.2illustrates an example of an apparatus configuration for detecting the position of a mark.FIG.2illustrates that a part of a detection optical system12(an optical axis of the detection optical system) and a part of an illumination optical system13(an optical axis of the illumination optical system) are common.

The illumination optical system13guides light from a light source14to the same optical axis as that of the detection optical system12using an optical member such as a prism15and irradiates the mold mark6and the substrate mark7therewith. As the light source14, a halogen lamp, an LED, or the like is used, for example. The light source14emits light with a wavelength that is different from the wavelength of the ultraviolet light10.

The prism15has a reflection film15afor reflecting light in a peripheral portion of a pupil surface of the illumination optical system13in an attachment surface. The reflection film15afunctions as an aperture diaphragm that defines the shape of pupil intensity distribution in the illumination optical system13. Also, the reflection film15aalso functions as an aperture diaphragm that defines the size of the pupil in the detection optical system12(or the numerical apertures NAo in the detection optical system12).

The prism15may be a half prism that has a semipermeable film in the attachment surface or may be replaced with a plate-shaped optical element with a reflection film provided thereon. Also, in order to change the pupil shapes in the illumination optical system13and the detection optical system12, the prism15may be replaceable with another prism using a switching mechanism such as a turret or a sliding mechanism. Also, the position at which the prism15is disposed may not be in the pupil surfaces or the vicinity thereof in the detection optical system12and the illumination optical system13. Note that, although the pupil shape of the illumination optical system13is defined by the reflection film15aof the prism15, the present invention is not limited thereto. For example, it is possible to obtain similar effects even if a mechanical diaphragm, a diaphragm depicted in a glass surface, or the like is disposed at the pupil position in the illumination optical system13.

FIG.3is a diagram illustrating a relationship between pupil intensity distribution (IL1to IL4) in the illumination optical system13and the numerical apertures NAo in the detection optical system12. InFIG.3, the size of the pupil in the pupil surface in the illumination optical system13is represented by the numerical apertures NAo in the detection optical system12.

In the first embodiment, the pupil intensity distribution in the illumination optical system13includes a first pole ILL a second pole IL2, a third pole IL3, and a fourth pole IL4. The illumination optical system13illuminates the mold mark6and the substrate mark7with light that is incident in a direction perpendicular to the direction (first direction) in which patterns of the mold mark6and the substrate mark7are aligned and light that is incident in parallel to such a direction. As described above, it is possible to form the plurality of poles, that is, the first pole IL1to the fourth pole IL4, from the one light source by disposing the reflection film15athat functions as an aperture diaphragm in the pupil surface in the illumination optical system13. In this manner, a plurality of light sources are not needed in a case in which the pupil intensity distribution having a plurality of poles (peaks) is formed.

Referring toFIGS.4A to4D, a principle of generation of moire due to diffraction light from the mold mark6and the substrate mark7and detection of relative positions of the mold mark6and the substrate mark7using such moire will be described. As illustrated inFIGS.4A and4B, a diffraction grating (first diffraction grating)18provided on the mold4as the mold mark6and a diffraction grating (second diffraction grating)19provided on the substrate2as the substrate mark7have slightly different cycles of patterns (gratings) in the measurement direction. If such two diffraction gratings with mutually different grating cycles are caused to overlap, a pattern having a cycle reflecting a difference between cycles of the diffraction gratings, that is, so-called moire, appears due to an interference between the diffraction light from the two diffraction gratings. Since a phase of the moire changes due to the relative positions of the diffraction gratings at this time, it is possible to obtain the relative positions of the mold mark6and the substrate mark7, that is, the relative positions of the mold4and the substrate2, by detecting the moire.

Specifically, if the diffraction grating18and the diffraction grating19with slightly different cycles are caused to overlap, then the diffraction light from the diffraction gratings18and19overlaps, and moire with a cycle reflecting the difference in cycles is thus generated as illustrated inFIG.4C. The positions of brightness and darkness (streak phase) of the moire change depending on the relative positions of the diffraction grating18and the diffraction grating19as described above. If the relative positions of the diffraction grating18and the diffraction grating19change in the X direction, for example, the moire illustrated inFIG.4Cchanges to the moire illustrated inFIG.4D. Since the moire enlarges the amount of actual positional deviation (the amount of change) between the diffraction grating18and the diffraction grating19and is generated as a streak with a large cycle, it is possible to highly accurately detect the relative positions of the diffraction grating18and the diffraction grating19even if resolution of the detection optical system12is low.

In order to detect such moire, a case in which the diffraction gratings18and19are detected in a bright field (the diffraction gratings18and19are illuminated from perpendicular directions, and diffraction light diffracted by the diffraction gratings18and19in the perpendicular directions is detected) will be considered. In this case, the detection optical system12detects zero-dimensional light from the diffraction gratings18and19. Since the zero-dimensional light is strong, and this may lead to a relative decrease in contrast of the moire and cause the intensity to fall within sensor detection intensity, the imprint apparatus has a configuration of a dark field for not detecting the zero-dimensional light (in other words, the diffraction gratings18and19are illuminated by oblique incident light). In the first embodiment, one of the diffraction gratings18and19is a checkerboard-shaped diffraction grating as illustrated inFIG.5A, while the other diffraction grating is the diffraction grating illustrated inFIG.5Bthat enables detection of moire with the configuration of the dark field. The diffraction grating illustrated inFIG.5Aincludes a pattern periodically aligned in the measurement direction (first direction) and a pattern periodically aligned in a direction (second direction) that perpendicularly intersects the measurement direction.

Referring toFIGS.3,5A, and5B, the diffraction gratings are irradiated with light from the first pole IL1and the second pole IL2, and the light is diffracted by the diffraction grating with the checkerboard shape. Here, light diffracted in the direction of the Z axis in the light diffracted by the diffraction grating is detected. Light diffracted in the Y direction has relative position information in the X direction, is incident on a detection region (NAo) on the pupil in the detection optical system12, and is then detected by an image pickup element16. Using this, the relative positions of the two diffraction gratings can be obtained.

In the relationship between the pupil intensity distribution illustrated inFIG.3and the diffraction gratings illustrated inFIGS.5A and5B, light from the third pole IL3and the fourth pole IL4is not used to detect such relative positions of the diffraction gratings. However, in a case in which relative positions of the diffraction gratings illustrated inFIGS.5C and5Dare detected, the light from the third pole IL3and the fourth pole IL4is used to detect the relative positions of the diffraction gratings while the light from the first pole IL1and the second pole IL2is not used to detect the relative positions of the diffraction gratings. Also, in a case in which the set of diffraction gratings illustrated inFIGS.5A and5Band the set of diffraction gratings illustrated inFIGS.5C and5Dare disposed in the same field of view of the detection optical system12, and the relative positions in the two directions are detected at the same time, the pupil intensity distribution illustrated inFIG.3is significantly effective.

FIG.6is a flowchart of an imprinting sequence in the related art. UsingFIG.6, the imprinting sequence in the related art will now be described. Note that the operations (processing) illustrated in the flowchart inFIG.6are controlled by the control unit11executing a computer program.

In the imprinting sequence in the related art, the imprint material3is applied to the substrate2first before the substrate2is transported into (installed in) the imprint apparatus. As the application, it is desirable that the imprint material3be uniformly applied to the entire surface of the substrate2by a spin coating method or the like that is typically used in a lithography apparatus or the like. Then, the substrate2with the imprint material3applied thereto in Step (process) S601is transported into the imprint apparatus first.

Next, the substrate2that has been transported into the imprint apparatus is placed on the substrate stage1after the substrate2is allowed to acclimate to the temperature and after position measurement and the like. The substrate2placed on the substrate stage1moves on to an imprinting process after further position measurement and the like. It is assumed that the mold4is mounted in the imprint apparatus prior to this. A pattern to be transferred (pattern formation) onto the substrate2and the mold mark6that is a mark to be used for the positioning relative to the substrate2are configured on the mold4. These are configured as an uneven structure on the mold4. Then, in Step S602, the pattern region to be imprinted on the substrate2placed on the substrate stage1and the mold4are caused to face each other.

Next, in Step S603, the substrate2and the mold4are brought into contact with each other via the imprint material3applied in advance, and the recessed portion of the uneven portion of the mold4configured as the pattern and the mold mark6on the mold4is filled therewith.

Here,FIGS.7A to7Dillustrate how the filling with the imprint material3is performed in Step S603.FIG.7Aillustrates a state of the substrate2and the mold4before contact with a solution (before contact) via the imprint material3. The state in which the imprint material3has been applied to the substrate2and the substrate2faces the mold4at this time is illustrated.FIG.7Billustrates a state in which the substrate2and the mold4are brought into contact with each other via the imprint material3. At this time, the recessed portion of the uneven portion (pattern formed portion) of the mold4is filled with the imprint material3, and the mold mark6formed on the mold4is filled therewith, due to a capillary phenomenon. As described above, it is necessary to irradiate the imprint material3with the ultraviolet light10through the mold4in order to harden the imprint material3. Therefore, a material that exhibits permeability with respect to the ultraviolet light10, such as quartz, for example, is used for the mold4. At this time, if the imprint material3and the mold4have similar values related to optical physical properties such as refractive indexes, it may be impossible or difficult to observe the mold mark6, and a failure may occur in the measurement of the relative positions of the substrate2and the mold4. Thus, the mold mark6configured of a material with different physical property values is used in the related art such that observation can be performed even when the recessed portion is filled.

FIG.7Cillustrates a state in which the recessed portion of the mold mark6is configured of a different material through deposition or the like.FIG.7Dillustrates a state in which a surface portion (projecting portion) of the mold mark6is configured of a different material. Examples of the different material include Al, Cu, and Cr. In addition, similar effects can also be obtained by changing physical properties such as a refractive index and an absorption coefficient of the substrate2by injecting ions or the like, for example.

It is possible to observe the mold mark6even after filling the recessed portion or the surface portion by configuring the recessed portion or the surface portion of the mold mark6using the different material in this manner and thereby to perform the measurement of the relative position with respect to the substrate mark7.

Returning toFIG.6, at least one of the mold4and the substrate2is driven in Step S604on the basis of the result of measuring the relative positions of the mold mark6and the substrate mark7. Then, the mold mark6and the substrate mark7are positioned to achieve a desired amount of overlapping.

Once the positioning of the mold mark6and the substrate mark7in Step S604ends, the region of the substrate mark7and the pattern region are irradiated with the ultraviolet light10to harden the imprint material3in Step S605(hardening process). Thereafter, the mold4is peeled off from the substrate2, thereby ending the transfer of the uneven pattern of the mold4onto the substrate2.

Next, whether or not the transfer onto the entire pattern region, to which the transfer is to be performed, on the substrate2has ended is determined in Step S606. If a pattern region to which the pattern has not yet been transferred remains, the pattern region on the substrate2is driven to be located below the mold4, and imprint processing in Steps S602to S605is carried out. If the pattern has been transferred to the entire pattern region, to which the transfer is to be performed, the processing proceeds to Step S607, the process for imprinting on the substrate2ends, and the substrate2is then transported out of the imprint apparatus. After the transport, processing on the following substrate is started.

Although the imprinting process in the related art has been described above, it is not possible to perform the measurement of the relative positions of the mold mark6and the substrate mark7during the filling with the imprint material3without the additional structure for the mold mark6as illustrated inFIGS.7A to7D.

However, a phenomenon in which such a structure is gradually worn or ground and disappears in a case in which each pattern region is filled with the imprint material3or in a case in which the mold4is regularly washed is seen. This may be a factor that determines a usable period (lifetime) of the mold4. The mold4is expensive, and a method providing a structure capable of withstanding longer-term use is needed in consideration of manufacturing costs of the device using the imprint apparatus.

Further, a measurement signal of the mold mark6may not be stable in the process of the filling with the structure illustrated inFIGS.7A to7D. This is because the recessed portion of the mold4is filled with the imprint material3, the structure of the mold mark6thus changes, and this causes a change in the detection signal. Although it is desired to perform the relative positioning as quickly as possible in order to enhance producibility, it is necessary to start the measurement of the mold mark6after sufficient filling of the mold mark6with the imprint material3ends due to the aforementioned phenomenon.

The method according to this embodiment illustrated inFIG.8can be said to be effective for solving these problems that may occur in the imprinting process in the related art. Hereinafter, an imprinting sequence according to the first embodiment will be described usingFIG.8. Note that the operations (processing) illustrated in the flowchart inFIG.8are controlled by the control unit11executing a computer program.

FIG.8is a diagram illustrating an imprinting sequence according to the first embodiment. Since steps up to S801and S802are similar to steps S601and S602illustrated usingFIG.6, description will be omitted. Note that it is preferable to have accurate position information in S803in order to irradiate a desired position with light. Therefore, the process of positioning the predetermined marks is preferably performed in S802that is a step in which the substrate2and the mold4are caused to face each other.

In Step S803, the imprint material3at a predetermined position, which includes the position of the substrate mark7that is a predetermined mark, outside the pattern region is irradiated with light with a predetermined wavelength to completely harden the imprint material3or increase the viscosity thereof (viscosity increasing process). In this case, the viscosity thereof is increased to be higher than the viscosity of the imprint material3in the pattern region.

FIG.9illustrates how Step S803that is a process of increasing the viscosity of the imprint material3at the predetermined position in the mark region is carried out. InFIG.9, an optical mechanism20is configured in addition to the configuration of the imprint apparatus in the related art illustrated inFIGS.1A and1B.

The drawing illustrates that the optical mechanism20reflects only predetermined ultraviolet light in the ultraviolet light10that can harden the imprint material3to expose (irradiate) the region including the substrate mark7in a limited manner. Examples of the optical element21include a digital micromirror device (DMD). This is an optical mechanism configuring multiple movable minute mirror surfaces and can reflect desired light at a desired angle. By using this, it is possible to reflect, at a desired angle, only light necessary to illuminate the predetermined region, which includes the substrate mark7, other than the pattern region in the ultraviolet light10with which the optical mechanism20is illuminated.

The method for irradiating the region including the substrate mark7with the ultraviolet light10is not limited thereto. For example, a system configuring an illumination field diaphragm at a position conjugated with the substrate surface and adapted to irradiate the desired position with the ultraviolet light10by transmitting the ultraviolet light10through a portion corresponding to the position of the substrate mark7may also be used. Alternatively, a system adapted to drive an irradiation position by guiding light using an ultraviolet LED, a fiber, or the like to irradiate the region including the substrate mark7may also be used.

The optical element21preferably configures a dielectric multilayer film that reflects the ultraviolet light10and transmits visible light, for example. Since the ultraviolet light10is reflected by the optical element21using this, the substrate2is irradiated therewith. Also, since the visible light is transmitted through the optical element21, there is an advantage that it is possible to use the optical mechanism20using the visible light to observe the state of the substrate2, observe and relatively position the mold4and the substrate mark7, and the like. It is thus possible to perform measurement for specifying the mark position at the time of the irradiation. For example, it is possible to check the positional relationship between the ultraviolet light irradiation unit and the mold4by measuring and recognizing the relative positions of the imprint apparatus and the mold4when the mold4is installed. If the relative positions of the mold mark6and the substrate mark7are measured when the mold4and the pattern region on the substrate2face each other next, it is possible to substantially specify the irradiation position. Since the imprint material3at the predetermined position, which includes the position of the substrate mark7that is the predetermined mark, other than the pattern region is hardened or the viscosity thereof is increased in a state in which the mold4and the substrate2face each other in this manner, it is possible to irradiate a targeted position of the imprint material3with the light with the predetermined wavelength.

Note that, although the region including the substrate mark7is irradiated with the light with the predetermined wavelength in S803, there is a possibility that hardening is not sufficiently performed if the total amount of irradiation (amount of exposure) of the imprint material3in this region is insufficient in S803to S806as will be described later. In addition, there is also a concern of the unhardened portion being pulled and peeled off together when the mold4is pulled and peeled off from the substrate2if the hardening of the imprint material3is not sufficiently performed. If etching or the like is performed thereon in the following process thereafter, a layer thickness that is different from that of the other region may be obtained, and the etching may be performed in an unexpected manner. In addition, it is also conceivable that a difference may occur in a degree of hardening of the imprint material3due to the difference in the amount of irradiation, and distortion (irregularity occurs) may occur.

It is thus desirable that the amount of irradiation obtained by adding the amount of prior irradiation with the light with the predetermined wavelength for the substrate mark7and the amount of irradiation with the light with the predetermined wavelength for the substrate mark7in the hardening process be equal to or greater than the amount of irradiation with the light with the predetermined wavelength for hardening the entire surface of the imprint material3in the pattern region in the hardening process. Also, since the portion in which each mark is configured is a region that is typically called a scribe line and includes no device pattern, it is desirable that the amount of irradiation obtained through the addition be equal to or greater than the amount of irradiation of the patterned portion as long as the distortion does not affect performance. Note that, in the irradiation, a region that includes not only the substrate mark7but also the periphery of the substrate mark7may be irradiated.

Returning toFIG.8, the mold4is then brought into contact with the imprint material3that has been supplied to the substrate2, the region of which including the substrate mark7has been irradiated, in Step S804.

FIGS.10A to10Fspecifically explain the state of the region including the substrate mark7at this time.FIG.10Aillustrates a state in which the imprint material3is applied onto the substrate mark7on the substrate2in advance and the substrate mark7faces the mold mark6. At this time, the viscosity of the imprint material3is still low, and if the substrate2and the mold4are directly brought into contact with the solution similarly to the related art, the recessed portion of the mold mark6is filled with the imprint material3due to a capillary force.

Thus,FIG.10Billustrates the state of the region including the substrate mark7after the region is irradiated with the ultraviolet light10using the aforementioned mechanism illustrated inFIG.9. An ultraviolet light irradiation region3′ represents the region that has been irradiated with the ultraviolet light10. Since the ultraviolet light irradiation region3′ is in a state after the ultraviolet curable imprint material3has been irradiated with the ultraviolet light10, a hardened state is illustrated. Even if the mold mark6is brought into contact with this region at the time of the imprinting, the imprint material3does not enter the furthest part of the recessed portion of the mold mark6because the imprint material3is hardened.FIG.10Cillustrates this state. Since a difference in physical property values (difference in refractive indexes) occurs in a portion of the recessed portion of the mold mark6that has not been filled in this manner, it is possible to observe the mold mark6. Note that, in S803, it is only necessary to cause the imprint material3to have such viscosity that the imprint material3does not enter the furthest part of the recessed portion of the mold mark6in S805in the first embodiment. In other words, it is possible to sufficiently perform positioning as long as the furthest portion of the recessed portion of the mold mark6is not completely filled with the imprint material3in S805after the mold4and the imprint material3are brought into contact with each other and the furthest portion of the recessed portion of the pattern on the mold4is completely filled with the imprint material3in S804. Therefore, it is not necessary to completely harden the imprint material3when the viscosity thereof is increased in S803, and it is only necessary to increase the viscosity to such an extent that the furthest portion of the recessed portion of the mold mark is not completely filled with the imprint material3in S805.FIG.10Dillustrates such a state in which contact into the solution has been achieved with the imprint material3not completely hardened and with the viscosity increased. Although the imprint material3has not been completely hardened and the mold mark6has partially been filled with the imprint material3as described above, the portion that has not yet been filled therewith is present at the furthest portion of the recessed portion of the mold mark6, and it is thus possible to observe the mold mark6.

As described above, the viscosity of the imprint material3at the predetermined position other than the pattern region is increased to be higher than the viscosity of the imprint material3in the pattern region before the mold4is brought into contact with the imprint material3in the pattern region on the substrate2. In this manner, the mold mark6is unlikely to be filled with the imprint material3when the mold4is brought into contact with the imprint material3, and it is thus possible to continue the positioning. Note that it is desirable to increase the viscosity of the imprint material3at the predetermined position to obtain such viscosity that the recessed portion of the mold mark6is not completely filled with the imprint material3even after twice the time required to form the pattern of the mold4on the imprint material3elapses, for example.

Returning toFIG.8, the processing proceeds to S805next. However, since Steps S805to S808are similar to Steps S604to S607illustrated usingFIG.6, description thereof will be omitted.

By performing the aforementioned processes, it is not necessary to add a structure needed for the imprinting process in the related art to the mold mark6. Also, if both the addition of a structure to the mold mark6and the method according to the first embodiment are employed together, the detection signal from the mold mark6becomes strong, and the mold mark6is more easily detected. In addition, since it is possible to maintain the minimum necessary intensity of the signal for detecting moire even in a case in which signal intensity decreases due to wearing of the additional structure for the mold4, this leads to elongation of the lifetime of the mold4.

Note that, in a case in which the structure as described above is added to the mold mark6, the amount of ultraviolet light (the amount of irradiation) used in the irradiation for hardening after transferring the pattern may decrease. If the amount of ultraviolet light decreases, the amount of irradiation for the hardening after the pattern transfer may become insufficient, and there is a possibility of this causing irregularity in a degree of hardening of the imprint material3and a failure occurring in the following processes. Therefore, the ultraviolet light10is irradiated in advance, and the total amount of irradiation light is controlled as in the first embodiment. It is thus possible to adjust a balance between the amount of ultraviolet light applied to the imprint material3in the region of the substrate mark7and the amount of ultraviolet light10applied to the pattern region other than the region of the substrate mark.

Also, there is a case in which a phenomenon of the imprint material3rising along the mold side surface when the mold4is brought into contact with the imprint material3occurs due to wettability of the side surface of the mold4and surface tension of the imprint material3. If the imprint material3is irradiated with the ultraviolet light10and is hardened in the hardening process with the imprint material3rising, the imprint material3with a projecting shape remains at an end of the mold. In order to avoid this, the outer peripheral portion of the pattern region may be irradiated with the ultraviolet light10before the contact with the solution to harden the imprint material3or increase the viscosity thereof. In other words, the imprint material3in the region including the substrate mark7may be irradiated with the ultraviolet light10to increase the viscosity, and the outer peripheral portion in the pattern region may be irradiated with the ultraviolet light10in S803. At this time, the viscosity of the imprint material3in the outer peripheral portion of the pattern region may be increased to be higher than the viscosity of the imprint material3in the pattern region inside the outer peripheral portion before the hardening process. Also, in this case, the irradiation with the ultraviolet light10may be performed on both the outer peripheral portion of the pattern region and the inside of the pattern region in S806.

Although the method of irradiating the imprint material3with the ultraviolet light10in advance in the imprinting method using the imprint material3that is hardened with the ultraviolet light10has been proposed as a method of hardening the imprint material3or increasing the viscosity thereof in the region including the substrate mark7in the first embodiment, the present invention is not limited thereto. In a case in which a thermosetting resin is used, for example, similar effects can be obtained by applying heat to the region including the portion of the substrate mark7through irradiation with infrared light or the like. Also, the method of irradiating the imprint material3with infrared light may be used instead of the irradiation with the ultraviolet light10as described above in the process of hardening the imprint material3or increasing the viscosity thereof in the outer peripheral portion of the pattern region as well.

In addition, similar effects can also be obtained by additionally dropping the imprint material (resin)24with higher viscosity at a desired position of the imprint material3that has been applied to the entire surface of the substrate2in advance.FIG.10Eillustrates how the imprint material24with higher viscosity, with which it is difficult to fill the substrate mark7, is additionally dropped onto the substrate mark7as illustrated in the first embodiment. Also, the state illustrated inFIG.10Fis a state in which the mold4has been brought into contact with the substrate2in the state inFIG.10E. The filling of the mold mark6is curbed due to the imprint material24with higher viscosity that is additionally dropped, and it is possible to keep the unfilled state.

The imprint material3may be hardened, or the viscosity thereof may be increased, by applying a compound25that promotes polymerization of the imprint material3that has been applied in advance to the region, which includes the substrate mark7, other than the pattern region using a similar method. As the application method, a method similar to that inFIG.10Emay be used. Also, the method illustrated inFIGS.10E and10Fis also included in the viscosity increasing process for hardening the imprint material3or increasing the viscosity thereof.

Second Embodiment

Next, an imprinting method according to a second embodiment will be described on the basis ofFIG.11.FIG.11is a flowchart illustrating the imprinting method according to the second embodiment. Note that the operations (processing) illustrated in the flowchart inFIG.11are controlled by the control unit11executing a computer program.

First, in Step S1101, a substrate2with the entire surface to which an imprint material3is applied is prepared and is then installed in the imprint apparatus. Next, in Step S1102, a region including a substrate mark7is irradiated with ultraviolet light10to harden the imprint material3or increase the viscosity thereof at a predetermined position until the mold4and the pattern region of the substrate2face each other, that is, in a state in which the substrate2and a mold4do not face each other.

Irradiation with the ultraviolet light10in the imprint apparatus in Step S1102will be described in more detail. In the second embodiment, a region, which includes the substrate mark7, other than the pattern region is irradiated with the ultraviolet light10. Since the used substrate mark7has a size of about 10 μm at least, it is only necessary for precision of the position of the irradiation with the ultraviolet light to be about several μm. It is thus possible to harden the imprint material3at the predetermined position by continuously or intermittently perform irradiation a plurality of times while moving one optical unit that is smaller than the substrate mark7. Also, the number of optical units is not limited to one, and a plurality of optical units for irradiation with an ultraviolet LED, for example, may be configured, and these may be driven to the substrate mark7to collectively or successively repeat the irradiation with the ultraviolet light.

FIGS.12A to12Cillustrate how the irradiation with the ultraviolet light10is performed in the imprint apparatus in Step S1102.

Since it is preferable that the ultraviolet light irradiation unit be as small as possible, only a small-sized light source22and an optical element23for narrowing the ultraviolet light10are illustrated inFIGS.12A to12C. The small-sized light source22may be an actual small-sized light source such as an ultraviolet LED or may be an emission end guided from a separately configured light source through an optical fiber or the like. The optical element23is a member for controlling the size and the shape of the beam of the ultraviolet light10with which the substrate2is illuminated and includes a lens, a field diaphragm, and the like. AlthoughFIGS.12A to12Cillustrate a form in which the ultraviolet light irradiation unit is driven, the substrate2may be driven up to a position at which the substrate2faces the ultraviolet light irradiation unit. The ultraviolet light irradiation unit is driven up to a desired substrate mark7on the basis of information regarding the substrate mark7obtained in advance. Once the ultraviolet light irradiation unit is driven up to the desired position of the substrate mark7, irradiation with the ultraviolet light10is started.FIG.12Aillustrates how the operation at this time is performed.FIGS.12A to12Cillustrate a configuration in which a desired region is irradiated by driving the ultraviolet light irradiation unit during the irradiation. Note that if the ultraviolet light irradiation unit has a sufficiently large irradiation region, it is not necessary to perform scanning, and it is only necessary to repeat the moving step and the irradiation.

Once the irradiation of the desired region ends, the ultraviolet light irradiation unit is driven up to a position of the next substrate mark7which is to be irradiated. At this time, the irradiation of the ultraviolet light10is not performed while moving above portions other than the substrate mark7.FIG.12Billustrates how the operation at this time is performed.

Then, once the ultraviolet light irradiation unit is moved up to the position of the next substrate mark7on which irradiation is to be performed, then the ultraviolet light irradiation unit is driven while irradiation with the ultraviolet light10is performed again.FIG.12Cillustrates how the operation at this time is performed. Since it is not necessary to drive the substrate2and only a small space is needed to perform these processes by using the aforementioned method, a size reduction of the apparatus can be achieved.

Also, the irradiation method is not limited thereto, and an optical system or the like including a DMD as illustrated in the first embodiment may be configured.

It is desirable that the viscosity increasing process through irradiation of the substrate mark7with ultraviolet light or the like in the second embodiment be performed at a position different from the position of the substrate stage1on which the substrate2is placed at the time of imprint in order to enhance producibility. For example, the position at which the substrate2waits before installation on the substrate stage1corresponds thereto.

Returning toFIG.11, the processing proceeds to S1103next. However, since S1103to S1107are similar to steps S804to S808illustrated usingFIG.8, description thereof will be omitted.

As described above, it is possible to perform the viscosity increasing process through the irradiation of the portion of the substrate mark7with the ultraviolet light10or the like in the region that is different from the region in which the imprinting process is performed according to the second embodiment. Also, since the imprinting process is performed similarly to the related art, the number of processes is partially reduced without leading to a decrease in producibility, and it is thus possible to improve a throughput.

Note that it is important to harden the imprint material3or to increase the viscosity thereof in the region, which includes the substrate mark7, other than the pattern region. Therefore, applying heat in a case of a thermosetting resin similarly to the first embodiment or additionally dropping the imprint material24with higher viscosity is also effective to continuously observe the mold mark6.

Third Embodiment

FIG.13is a flowchart of an exposure method for increasing the viscosity through irradiation with ultraviolet light10outside the imprint apparatus or the like according to a third embodiment. The third embodiment will be described on the basis ofFIG.13. Note that the operations (processing) illustrated in the flowchart inFIG.13are controlled by the control unit11executing a computer program.

First, in Step S1301, a substrate2to which an imprint material3has been applied is installed in an apparatus (pre-processing apparatus) outside the imprint apparatus. Next, in Step S1302, the imprint material3at a predetermined position, which includes the position of a substrate mark7that is a predetermined mark, other than a pattern region is irradiated with light with a predetermined wavelength to completely harden the imprint material3or increase the viscosity thereof (viscosity increasing process). In this case, the viscosity is increased to be higher than the viscosity of the imprint material3in the pattern region. Next, in Step S1303, the entire region to be imprinted is irradiated with predetermined light, and the substrate2is transported out of the pre-processing apparatus after the irradiation ends.

Next, in Step S1304, the substrate2after ending the pre-processing is installed in the imprint apparatus. Then, the processing proceeds to S1305. However, since Steps S1305to S1310are similar to Steps S602to S607illustrated usingFIG.6, description thereof will be omitted.

As described above, the substrate2to which the imprint material3has been applied is prepared in advance to be used in an imprint apparatus or the like having a section adapted to bring a patterned portion of a mold4into contact with the imprint material3in a predetermined pattern region on the substrate2to form a pattern in the third embodiment. Note that it is assumed that the imprint material3is applied to the entire surface of the substrate2in the third embodiment. Also, the pre-processing apparatus is used to pretreat the substrate2before the substrate2, to which the imprint material3has been applied, is installed in the imprint apparatus. In the pre-processing apparatus, a reticle (original plate) that conforms to the used substrate2is prepared before the pattern is formed on the imprint material3on the substrate2using a contact section of the imprint apparatus. In addition, a viscosity increasing section adapted to increase the viscosity of the imprint material3at the predetermined position, which includes the position of the predetermined mark provided on the substrate2, other than the pattern region to be higher than the viscosity of the imprint material3in the pattern region is included. Examples of the used apparatus include an i-beam lithography apparatus. Since the region irradiated with the ultraviolet light10is of a μm order as described above, it is not necessary to perform fine positioning control. Thus, the i-beam lithography apparatus with high producibility is effectively used. It is a matter of course that another type of lithography apparatus or the optical system according to the first or second embodiment as a dedicated machine of this case may be provided outside the imprint apparatus. Also, the pre-processing apparatus as described above, for example, may be provided inside or outside the imprint apparatus.

The viscosity increasing processing to harden the imprint material3or increase the viscosity thereof in the region including the substrate mark7is performed in a stage prior to the installation into the imprint apparatus, that is, a stage in which the substrate for imprinting is manufactured using the pre-processing apparatus. The substrate for imprinting is manufactured through the viscosity increasing processing, and the substrate2is then installed in the imprint apparatus. After the substrate2is installed into the imprint apparatus, the substrate2is treated in the hardening process, and the post processing is then performed on the substrate2including the imprint material3.

Note that it is important to harden the imprint material3or to increase the viscosity thereof in the region, which includes the substrate mark7, other than the pattern region. Therefore, applying heat in a case of a thermosetting resin similarly to the first embodiment or additionally dropping the imprint material24with higher viscosity is also effective to continuously observe the mold mark6.

(Embodiment of Article Manufacturing Method)

A method for manufacturing an article according to this embodiment is suitable for manufacturing an article such as a microdevice including a semiconductor device or an element with a fine structure, for example. The method for manufacturing an article according to this embodiment includes a process for forming a pattern on an imprint material applied to a substrate using the aforementioned imprint apparatus (a process for performing imprint processing on the substrate) and a process for working the substrate on which a pattern has been formed in such a process. Further, such a manufacturing method includes other known processes (oxidation, film formation, deposition, doping, flattening, etching, composition peeling, dicing, bonding, packaging, and the like). The method for manufacturing an article according to this embodiment is advantageous in terms of at least one of performance, quality, producibility, and manufacturing costs of the article as compared with the method in the related art.

The pattern of a hardened object shaped using the imprint apparatus is permanently used at least as a part of various articles or is temporarily used when various articles are manufactured. The articles include an electric circuit element, an optical element, an MEMS, a recording element, a sensor, a mold, or the like. Examples of the electric circuit element includes volatile or non-volatile semiconductor memories such as a DRAM, an SRAM, a flash memory, and an MRAM and semiconductor elements such as an LSI, a CCD, an image sensor, and an FPGA. Examples of the mold include a mold for imprint.

The pattern of the hardened object is directly used as at least a partial component of the aforementioned article or is temporarily used as a composition mask. After etching, ion injection, or the like is performed in the substrate working process, the composition mask is removed.

Next, a specific method for manufacturing an article will be described with reference toFIG.14. As illustrated inFIG.14A, a substrate1zsuch as a silicon substrate with a surface on which a working target material2zsuch as an insulating element is formed is prepared, and an imprint material3zis then applied to the surface of the working target material2zby an inkjet method or the like. Here, how the imprint material3zin the form of a plurality of liquid droplets has been applied onto the substrate is illustrated.

As illustrated inFIG.14B, a side of a mold4zfor imprint on which an uneven pattern has been formed is directed to and is caused to face the imprint material3zon the substrate. As illustrated inFIG.14C, the substrate1zto which the imprint material3zhas been applied and the mold4zare brought into contact with each other, and a pressure is applied thereto. The clearance between the mold4zand the working target material2zis filled with the imprint material3z. If irradiation with light as an energy for hardening is performed through the mold4zin this state, then the imprint material3zis hardened.

As illustrated inFIG.14D, if the mold4zis pulled and peeled off from the substrate1zafter the imprint material3zis hardened, then the pattern of the hardened object of the imprint material3zis formed on the substrate1z. The pattern of the hardened object has a shape in which the recessed portion of the mold corresponds to a projecting portion of the hardened object while the projecting portion of the mold corresponds to the recessed portion of the hardened object. In other words, the uneven pattern of the mold4zis transferred to the imprint material3z.

As illustrated inFIG.14E, if etching is performed using the pattern of the hardened object as an etching-resistant mask, a portion that has no hardened object or has a thinly remaining hardened object in the surface of the working target material2zis removed, and a groove5zis obtained. As illustrated inFIG.14F, if the pattern of the hardened object is removed, it is thus possible to obtain an article with the groove5zformed on the surface of the working target material2z. Although the pattern of the hardened object is removed here, the pattern may not be removed after working and may be used as an interlayer insulating film included in a semiconductor element or the like, that is, a component of the article, for example. Note that although the example in which a mold for transferring a circuit pattern provided with an uneven pattern is used as the mold4zhas been described above, the mold4zmay be a flat plane template having a flat plane portion with no uneven pattern.

Also, a computer program that realizes the functions of the aforementioned embodiment describing a part or an entirety of the control in the aforementioned embodiments may be supplied to an imprint apparatus or the like via a network or various storage media. Then, a computer (or a CPU, an MPU, or the like) in the imprint apparatus or the like may read and execute the program. In this case, the program and the recording media storing the program also configure the present invention.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2019-157234, filed Aug. 29, 2019, which is hereby incorporated by reference wherein in its entirety.