JP2014110367A - Nanoimprint method and method for manufacturing patterned substrate using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce generation of film thickness irregularity or unfilled defects in a nanoimprinting process even when liquid droplets are laterally displaced.SOLUTION: After liquid droplets 23 are disposed and before a rugged pattern 16 is brought into contact with the liquid droplets 23 in a nanoimprint method, a plurality of liquid droplets 23 displaced on a process target substrate 20 are rearranged to be disposed at predetermined positions 24 on the process target substrate 20; then the rugged pattern is pressed to the surface of the process target substrate 20 where the liquid droplets 23 are applied so as to transfer the rugged pattern onto a curable resin film 25 composed of the plurality of liquid droplets 23 bonded to one another. Otherwise, a plurality of droplets 23 are disposed at a position apart from the predetermined position 24 on the process target substrate 20 so as to compensate the lateral displacement of the plurality of droplets 23 on the process target substrate 20.

Description

  The present invention relates to a nanoimprint method using a mold having a fine concavo-convex pattern on its surface and a method for producing a patterned substrate using the same.

  Nanoimprinting involves pressing a mold (generally called a mold, stamper, or template) with a concavo-convex pattern against the resist (curable resin) applied on the substrate to be transferred (imprinting), and then dynamically deforming the resist. This is a technology for transferring a fine pattern to a resist film precisely by flowing it. Once a mold is made, it is economical because nano-level microstructures can be easily and repeatedly molded, and it is a transfer technology with little harmful waste and emissions. Application to is expected.

  Nanoimprinting is performed by, for example, a step-and-repeat nanoimprinting apparatus as disclosed in Patent Document 1. The nanoimprint apparatus is provided with various facilities such as an imprint head for holding a mold, an XY stage for holding a substrate, a dispenser for supplying a resist, an exposure light source, a temperature control system, an atmosphere cleaning system, and a force gauge. According to such an apparatus, each process of nanoimprint can be implemented consistently.

  Patent Document 2 discloses that an imprint head is provided with means for supplying helium to a gap space between a mold and a resist. According to such an apparatus, when the mold and the resist are brought into close contact with each other, helium is blown into the gap space to replace the atmosphere, and by utilizing the property that helium permeates the mold, the mold and the resist are brought into close contact with each other. Generated unfilled defects (defects due to residual gas) can be reduced.

  However, when nanoimprinting is performed using the above-described apparatus, for example, when the XY stage moves, when the temperature control or atmosphere cleaning system fan is rotated, and further, the gap between the mold and the resist in the apparatus. When helium is blown into the space, there may be a problem that the resist droplet disposed on the substrate is displaced from the position where it is initially disposed. If the resist droplet is displaced, it may cause, for example, uneven thickness of the resist film or unfilled defects.

  For example, as a countermeasure for preventing the lateral displacement of the droplets as described above, there is a method in which an enclosing structure surrounding the droplets is formed on the substrate on which the droplets are arranged, and the droplets are arranged inside the enclosing structure. (Patent Document 3).

US Patent No. 6900881 Special table 2007-509769 gazette JP 2011-251508 A

  However, the above-described method may cause a problem that the surrounding structure remains as a contamination in the resist film and affects subsequent processes.

  Therefore, rather than preventing the lateral displacement of the droplets by the surrounding structure, there is a demand for a method that can reduce the occurrence of uneven film thickness and unfilled defects even when the lateral displacement of the droplets occurs.

  The present invention has been made in response to the above-described demand, and in nanoimprinting, a nanoimprinting method that can reduce the occurrence of film thickness unevenness and unfilled defects even when the above-described lateral displacement of droplets occurs. It is intended to provide.

  Furthermore, an object of the present invention is to provide a method for manufacturing a patterned substrate that can reduce the occurrence of pattern defects in the manufacture of a patterned substrate.

In order to solve the above problem, a first nanoimprint method according to the present invention includes:
In the nanoimprint method using a mold having a fine uneven pattern on the surface,
Place a plurality of droplets made of curable resin on the substrate to be processed,
After the droplets are arranged, the plurality of droplets are re-repositioned so that the plurality of droplets displaced on the substrate to be processed are arranged at predetermined positions on the substrate to be processed before the uneven pattern comes into contact with the droplets. Place and
After the plurality of droplets are rearranged, the concavo-convex pattern is pressed onto the surface of the substrate to which the droplets are applied, and the concavo-convex pattern is transferred to the curable resin film composed of a combination of the plurality of droplets. To do.

  In the nanoimprint method according to the present invention, it is preferable that the plurality of droplets be rearranged by shifting the droplets with an air flow generated in the imprint apparatus. In this case, the airflow can be generated by a fan attached to the imprint apparatus, or it is attached to a mold holding part for holding a mold and / or a substrate holding part for holding a substrate to be processed in the imprint apparatus. An airflow can be generated at the airflow generating section.

  In the nanoimprint method according to the present invention, it is preferable that the plurality of droplets be rearranged by tilting the substrate to be processed on which the plurality of droplets are disposed and shifting the droplets.

  In the nanoimprint method according to the present invention, the positional relationship between the registration mark serving as a reference for the position on the substrate to be processed and a plurality of droplets is observed, and the positional relationship is necessary for the rearrangement of the plurality of droplets. It is preferable to terminate the rearrangement of the plurality of droplets when a predetermined requirement is satisfied.

  Further, in the nanoimprint method according to the present invention, the generation requirements of the airflow necessary for the rearrangement of the plurality of droplets are obtained before the plurality of droplets are arranged, and when the generation requirements are satisfied, It is preferable to end the arrangement. Alternatively, in the nanoimprint method according to the present invention, the tilt requirement of the substrate to be processed necessary for the rearrangement of the plurality of droplets is obtained before arranging the plurality of droplets, and when the tilt requirement is satisfied, the plurality of droplets It is preferable to end the rearrangement.

The second nanoimprint method according to the present invention is:
Using a mold having a fine concavo-convex pattern on the surface, a plurality of droplets made of a curable resin are arranged on the substrate to be processed, and the concavo-convex pattern is pressed against the surface of the substrate to be processed to apply a plurality of droplets. In the nanoimprint method of transferring a concavo-convex pattern to a curable resin film composed of a combination of droplets of
After the droplets are placed and before the concave-convex pattern comes into contact with the droplets, the plurality of droplets are displaced on the substrate to be processed, so that the plurality of droplets are arranged at predetermined positions on the substrate to be processed. A plurality of droplets are arranged at a position away from a predetermined position on the substrate to be processed.

A method for producing a patterned substrate according to the present invention includes:
Forming a curable resin film having a concavo-convex pattern transferred on the substrate by the nanoimprint method described above,
By etching the substrate using the curable resin film as a mask, a concavo-convex pattern corresponding to the concavo-convex pattern transferred to the curable resin film is formed on the substrate.

  In the first nanoimprint method according to the present invention, a plurality of droplets are rearranged, and then a concavo-convex pattern is pressed against the surface of the substrate to be processed which has been coated with the droplets to form a curable resin composed of a combination of the plurality of droplets. A concavo-convex pattern is transferred to the film. In other words, in the present invention, even if the positions of a plurality of droplets are shifted on the substrate to be processed, the mold can be pressed against the substrate to be processed with an appropriate droplet arrangement, so that uneven film thickness and unfilled defects occur. Can be reduced.

  In the second nanoimprint method according to the present invention, a plurality of droplets are arranged at a position away from a predetermined position on the substrate to be processed so as to cancel the deviation of the plurality of droplets on the substrate to be processed. It is characterized by doing. In other words, even in the present invention, even if the positions of a plurality of droplets are shifted on the substrate to be processed, the mold can be pressed against the substrate to be processed with an appropriate droplet arrangement. Can be reduced.

  Moreover, since the manufacturing method of the patterned substrate which concerns on this invention transfers an uneven | corrugated pattern to curable resin film by the said nanoimprint method which can reduce generation | occurrence | production of a film thickness nonuniformity and an unfilled defect, It is possible to reduce the occurrence of pattern defects in manufacturing.

It is the schematic which shows the one part process of the nanoimprint method in 1st Embodiment. It is a schematic sectional drawing which shows a nanoimprint apparatus. It is a schematic plan view which shows a nanoimprint apparatus. It is the schematic which shows the structural example of a mold holding part. It is the schematic which shows the process of the other rearrangement method of the droplet in 1st Embodiment. It is the schematic which shows the process of the droplet rearrangement method in 2nd Embodiment.

  Hereinafter, although an embodiment of the present invention is described using a drawing, the present invention is not limited to this. In addition, for easy visual recognition, the scale of each component in the drawings is appropriately changed from the actual one.

“First Embodiment of Nanoimprint Method”
First, a first embodiment of the nanoimprint method will be described. FIG. 1 is a schematic diagram illustrating some steps of the nanoimprint method according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing a nanoimprint apparatus 1 for performing the nanoimprint method of the present embodiment. FIG. 3 is a schematic plan view showing the nanoimprint apparatus 1.

  The nanoimprint method of this embodiment is implemented using the apparatus 1 shown in FIG. Specifically, in the nanoimprint method of the present embodiment, a mold 10 having a fine concavo-convex pattern 16 and a substrate to be processed 20 are mounted on the nanoimprint apparatus 1, and a plurality of resist materials are formed on the substrate to be processed 20. After the droplets 23 are arranged (FIG. 1a), the plurality of droplets 23 (FIG. 1b) shifted laterally on the substrate 20 before the concave-convex pattern 16 comes into contact with the droplets 23 after the droplets 23 are arranged are covered. A plurality of droplets 23 are rearranged so as to be arranged at a predetermined position 24 on the processed substrate 20 (FIG. 1c), and after the plurality of droplets 23 are rearranged, the uneven pattern 16 is formed on the substrate 20 to be processed. The concave-convex pattern 16 is transferred to a resist film formed by combining a plurality of liquid droplets 23 by being pressed against the surface on which the liquid droplets 23 are applied (FIG. 1d).

(Nanoimprinting device)
As shown in FIG. 2, the nanoimprint apparatus 1 includes an exterior 2 in which fan filter units 3 and 4 are attached to a ceiling portion and a side wall, and further, for example, a mold holding portion (or an imprint head) ) 11, an XY stage 21, an exposure light source 30, an observation unit 31, a droplet application unit 32, a mold and substrate transport unit 40, and a mold and substrate carry-in / out unit 41. 2 also shows the mold 10 held by the mold holding unit 11 and the substrate 20 to be processed held by the XY stage 21 that also functions as the substrate holding unit.

  The fan filter units 3 and 4 are controlled by a temperature control system and an atmosphere cleaning system (not shown) in the device 1 to supply gas into the device 1 and suck gas in the device 1. As shown in FIG. 3, the fan filter unit 3 is provided on the ceiling of the exterior 2 of the apparatus 1, and the fan filter unit 4 is provided on the four side walls of the exterior 2.

  The mold holding unit 11 has a suction port 12, and holds the mold 10 by the suction force from the suction port 12. The mold holding unit 11 is movable in the vertical direction in FIG. 2, and imprinting is executed when the mold holding unit 11 is lowered. Further, a hole 14 for exposure and observation is provided in the center of the mold holding portion 11, and observation during exposure and imprinting with respect to the resist is performed through the hole 14.

  Furthermore, the airflow generation part 13 is provided in the mold holding part 11 of this embodiment. When the atmosphere in the gap between the mold 10 and the substrate 20 to be processed is replaced with helium, the airflow generation unit 13 supplies helium. Further, the air flow generation unit 13 can generate an air flow in the gap when the mold 10 and the substrate to be processed 20 face each other. For example, FIG. 4 is a schematic diagram illustrating a configuration example of the mold holding unit 11. In FIG. 4a, a plurality of openings 13a for ejecting and / or sucking gas are provided around the region 15 where the mold 10 is mounted. A gas is blown out and / or sucked from the plurality of openings 13a, whereby an air flow is generated in the gap between the mold 10 and the substrate 20 to be processed. The intensity of the airflow can be increased or decreased based on the amount of gas ejected and / or sucked from the plurality of openings 13a per unit time. For example, if the amount of gas to be ejected and / or sucked is increased per unit time, the strength of the airflow increases. Further, the direction of the airflow can be controlled based on the setting of which opening among the plurality of openings 13a is used to eject or suck the gas. For example, in FIG. 4 a, when gas is ejected from the upper opening 13 a of the region 15 and gas is sucked from the lower opening 13 a (the left and right openings 13 a are not used), On the contrary, when the gas is sucked from the upper opening 13a and the gas is ejected from the lower opening 13a, the airflow flowing from the lower side to the upper side of the region 15 is generated. be able to. Furthermore, if the left and right openings 13a are also used, fine control of the direction of airflow is possible.

  Further, in FIG. 4b, as in FIG. 4a, a plurality of openings 13b for ejecting and / or sucking gas are provided around the region 15 where the mold 10 is mounted. In particular in FIG. 4b, a row of openings 13b is provided around the region 15 in double (in parallel). In FIG. 4 c, a rectangular opening 13 c for ejecting and / or sucking gas is provided around the region 15 where the mold 10 is mounted. In FIG. 4d, similarly to FIG. 4c, a rectangular opening 13d for ejecting and / or sucking a gas is provided around the region 15 where the mold 10 is mounted. In particular, in FIG. 4 d, the openings 13 d are provided twice (in parallel) around the area 15.

  The XY stage 21 functions as a substrate holding unit for installing the substrate 20 to be processed, and sucks and holds the substrate to be processed by, for example, a suction port (not shown). The XY stage 21 can move in the XY plane (a plane perpendicular to the paper surface in FIG. 2) by moving along the stage rail 22 and can be tilted. For example, the XY stage 21 moves so that the substrate to be processed 20 comes under the droplet applying unit 32 when applying resist droplets, and is processed under the mold holding unit 11 when imprinting. It moves so that the board | substrate 20 may come.

  The exposure light source 30 is a light source that emits ultraviolet light for curing the resist, for example. The observation unit 31 is an optical device for observing the arrangement of droplets on the substrate to be processed and the state of imprinting. As such an optical apparatus, for example, an imaging element such as an optical microscope or a CCD device can be used. The exposure light source 30 and the observation unit 31 can be moved to positions facing the exposure and observation holes 14 and are used after being moved as necessary.

  The droplet applying unit 32 is a mechanism for arranging droplets made of resist on the substrate 20 to be processed. The droplet applying unit 32 applies droplets by a method that can place a predetermined amount of droplets at a predetermined position on the substrate 20 to be processed, such as an ink jet method or a dispensing method. When disposing the resist droplets on the substrate, an ink jet printer or a dispenser may be used depending on the desired droplet amount. For example, there are methods such as using an ink jet printer when the amount of droplets is less than 100 nl, and using a dispenser when the amount is 100 nl or more.

  Examples of the inkjet head that discharges the resist from the nozzle include a piezo method, a thermal method, and an electrostatic method. Among these, a piezo method capable of adjusting an appropriate amount of liquid (amount per droplet disposed) and a discharge speed is preferable. Before disposing the resist droplets on the substrate, the droplet amount and ejection speed are adjusted in advance. For example, the appropriate amount of liquid may be increased at a position on the substrate corresponding to a region where the space volume of the concave / convex pattern of the mold is large, or may be decreased at a position on the substrate corresponding to a region where the spatial volume of the concave / convex pattern of the mold is small. It is preferable to adjust. Such adjustment is appropriately controlled according to the droplet discharge amount (the amount per discharged droplet). Specifically, when the droplet amount is set to 5 pl, the droplet amount is controlled to be ejected to the same place five times using an inkjet head having a droplet ejection amount of 1 pl. The amount of droplets can be obtained, for example, by measuring the three-dimensional shape of droplets discharged on the substrate under the same conditions in advance with a confocal microscope or the like and calculating the volume from the shape.

  After adjusting the droplet amount as described above, droplets are arranged on the substrate according to a predetermined droplet arrangement pattern. The droplet arrangement pattern is constituted by two-dimensional coordinate information indicating a “predetermined position” on the substrate on which the droplet is to be arranged.

  The transport unit 40 is a mechanism that receives the mold 10 or the substrate to be processed 20 stocked in the carry-in / out unit 41 from the carry-in / out unit 41 and transports it to the mold holding unit 11 or the XY stage 21, respectively.

(mold)
The mold 10 used in the present embodiment can be manufactured by the following procedure, for example. First, a PHS (polyhydroxy styrene) -based chemically amplified resist, a novolac resist, a resist solution mainly composed of an acrylic resin such as PMMA (polymethyl methacrylate), etc. is applied onto a Si substrate by spin coating, A resist layer is formed. Thereafter, the Si substrate is irradiated with laser light (or an electron beam) while being modulated corresponding to the desired concavo-convex pattern, and the concavo-convex pattern is exposed on the resist layer surface. Thereafter, the resist layer is developed, and selective etching is performed by reactive ion etching (RIE) or the like using the developed resist layer pattern as a mask to obtain a Si mold having a predetermined uneven pattern.

  On the other hand, the mold is not limited to this, and a quartz mold can also be used. In this case, the quartz mold can be manufactured by a method similar to the method for manufacturing the Si mold described above, a method for manufacturing a patterned substrate (compound plate) described later, or the like.

  The mold 10 may have a mesa structure including a mesa portion (a portion whose upper surface is relatively flat and higher than the periphery) and a flange portion around the mesa portion. The step of the mesa portion is preferably 1-1000 μm, more preferably 10-500 μm, and still more preferably 20-100 μm. When nanoimprinting is performed using a mesa mold, the contact area between the mold and the resist is reduced compared to when using a flat mold, and the mold can be removed from the resist with a small force. There is. For example, when a pattern is repeatedly transferred (step-and-repeat) to the same substrate, a mesa-type mold is used so that the next pattern is transferred to the mold first. There is also an advantage that the previously transferred pattern can be prevented from being crushed by interference with the pattern.

(Release processing)
In the present invention, in order to improve the releasability between the resist and the surface of the mold 10, it is preferable to perform a release treatment on the uneven pattern surface of the mold 10. As a mold release agent used for the mold release treatment, Opkin (registered trademark) DSX manufactured by Daikin Industries, Ltd., Novec (registered trademark) EGC-1720 manufactured by Sumitomo 3M Co., Ltd., and the like are used as fluorine-based silane coupling agents. . In addition, known fluorine resins, hydrocarbon lubricants, fluorine lubricants, fluorine silane coupling agents, and the like can be used.

(Processed substrate)
The substrate 20 to be processed for imprinting is preferably a quartz substrate for the Si mold in order to enable exposure to a resist. The quartz substrate is appropriately selected according to the purpose without particular limitation as long as it has light transparency and a thickness of 0.3 mm or more. For example, a quartz substrate surface coated with a silane coupling agent, an organic layer made of a polymer for improving adhesion to a resist, and the like, Cr, W, Ti, Ni, Ag, A laminate of metal layers made of Pt, Au, etc., a laminate of metal oxide film layers made of CrO ₂ , WO ₂ , TiO _2, etc. on a quartz substrate, and the surface of the laminate with a silane coupling agent The thing etc. which were coat | covered are mentioned. The thickness of the organic material layer, metal layer or metal oxide film layer is usually 30 nm or less, preferably 20 nm or less. This is because when the thickness exceeds 30 nm, the UV transmittance is lowered and the resist is hard to be cured.

  The above-mentioned “having light transparency” specifically means that the resist is sufficiently cured when light is incident from the other surface so as to be emitted from one surface of the substrate 20 on which the resist is formed. It means that at least the transmittance of light having a wavelength of 200 nm or more from the other surface to the one surface is 5% or more.

  The thickness of the quartz substrate is usually preferably 0.3 mm or more. This is because if it is 0.3 mm or less, it is likely to be damaged by pressing during handling or imprinting.

  On the other hand, the shape, structure, size, material and the like of the substrate for the quartz mold are not particularly limited, and can be appropriately selected according to the purpose. For example, when the application is an information recording medium, the shape is a disk shape. The structure may be a single layer structure or a laminated structure. The material can be appropriately selected from those known as substrate materials, and examples thereof include silicon, nickel, aluminum, glass, and resin. These board | substrate materials may be used individually by 1 type, and may use 2 or more types together. The substrate may be appropriately synthesized or a commercially available product may be used. Moreover, what coat | covered the surface with the silane coupling agent may be used. There is no restriction | limiting in particular as thickness of a board | substrate, Although it can select suitably according to the objective, 0.05 mm or more is preferable and 0.1 mm or more is more preferable. This is because if the thickness of the substrate is less than 0.05 mm, the substrate may be bent when the substrate and the mold are in close contact, and a uniform contact state may not be ensured.

  The substrate 20 may have a mesa structure so that a region to which the uneven pattern is transferred is located on the mesa portion. Due to the presence of this pedestal, contact with the mold can be limited to the surface of the pedestal, so that contact with the structure existing outside the pattern formation region of the substrate can be avoided. A preferable range of the step of the mesa portion is the same as that of the mold. The effect described above can be obtained if either the mold or the substrate has a mesa structure.

(Resist)
The resist as the curable resin is not particularly limited, but in this embodiment, for example, a photopolymerization initiator (about 2% by mass) and a fluorine monomer (0.1 to 1% by mass) are added to the polymerizable compound. In addition, a prepared resist can be used.

  Moreover, antioxidant (about 1 mass%) can also be added as needed. The resist prepared by the above procedure can be cured by ultraviolet light having a wavelength of 360 nm. For those having poor solubility, it is preferable to add a small amount of acetone or ethyl acetate for dissolution, and then distill off the solvent.

Examples of the polymerizable compound include benzyl acrylate (Biscoat (registered trademark) # 160: manufactured by Osaka Organic Chemical Co., Ltd.), ethyl carbitol acrylate (Biscoat (registered trademark) # 190: manufactured by Osaka Organic Chemical Co., Ltd.), polypropylene glycol di In addition to acrylate (Aronix (registered trademark) M-220: manufactured by Toagosei Co., Ltd.), trimethylolpropane PO-modified triacrylate (Aronix (registered trademark) M-310: manufactured by Toagosei Co., Ltd.), etc. The compound A etc. which are represented can be mentioned.
Structural formula 1:

  The polymerization initiator may be 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (IRGACURE®). 379: manufactured by Toyotsu Chemiplus Co., Ltd.) and the like.

Moreover, as said fluorine monomer, the compound B etc. which are represented by following Structural formula 2 etc. can be mentioned.
Structural formula 2:

(Imprint method)
Before bringing the mold 10 into contact with the resist, it is preferable to reduce the residual gas by reducing the atmosphere between the mold 10 and the nanoimprint substrate to a reduced pressure or vacuum atmosphere. However, in a high vacuum atmosphere, the resist before curing is volatilized and it may be difficult to maintain a uniform film thickness. Therefore, a method of reducing the residual gas is preferably adopted by setting the atmosphere between the mold 10 and the substrate to a He atmosphere or a reduced pressure He atmosphere. Since He permeates the quartz substrate, the trapped residual gas (He) gradually decreases. Since it takes time to permeate He, it is more preferable to use a reduced pressure He atmosphere. The reduced pressure atmosphere is preferably 1 to 90 kPa, and particularly preferably 1 to 10 kPa.

  The mold 10 and the substrate coated with the resist are brought into contact with each other after they are aligned so as to have a predetermined relative positional relationship. An alignment mark is preferably used for alignment. The alignment mark is formed by a concavo-convex pattern that can be detected by an alignment camera, moire interferometry, or the like. The alignment accuracy is preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 100 nm or less.

  In particular, according to the present invention, before the mold 10 and the resist are brought into contact with each other, a plurality of droplets 23 laterally displaced on the substrate to be processed 20 before the concave / convex pattern 16 is brought into contact with the droplets 23 after the droplets 23 are arranged are covered. The plurality of droplets 23 are rearranged so as to be arranged at a predetermined position 24 on the processed substrate 20.

For example, when the XY stage 21 moves, when the fans 3 and 4 of the temperature control or atmosphere cleaning system are turned, and when helium is blown into the gap space between the mold 10 and the resist in the apparatus 1, etc. There is a problem that the resist droplet 23 arranged on the processed substrate 20 is laterally shifted from the position where it is initially arranged. For example, in FIG. 1b, when the substrate 20 to be processed (FIG. 1a) that has moved in the direction of the arrow 5 with the movement of the XY stage stops, the position of the droplet 23 is the position optimized in the imprint. state there is shown a lateral by lateral shift amount delta ₁ from a predetermined position 24, which is set as. Further, the position of the droplet 23 is also shifted from the predetermined position 24 as described above by the airflow B generated by the fan filter units 3 and 4 and the airflow generated by the airflow generation unit 13 at the time of helium replacement. There is.

  In general, the droplet arrangement pattern indicates the droplet arrangement on the substrate optimized in consideration of the uneven pattern of the mold. Therefore, it is preferable to avoid that the position of the droplets arranged according to the droplet arrangement pattern is subsequently changed unintentionally. Therefore, the operation of moving the droplets 23 anew so that the positions of the plurality of droplets 23 laterally displaced on the substrate 20 to be processed become the predetermined positions 24 on the substrate 20 to be processed, that is, rearrangement of the droplets 23 is performed. Do. Note that the droplet 23 only needs to be at the predetermined position 24 at the time of imprinting, and therefore, the predetermined position 24 and the position at which the droplet 23 is initially disposed do not necessarily coincide with each other.

  As a method of rearranging the droplets, for example, as shown in FIG. 1, there is a method of moving the droplets using the air flow 50 generated by the fan filter units 3 and 4 and the air flow generation unit 13. For example, the liquid droplets 23 shifted laterally by the airflow generated by the fan filter units 3 and 4 are rearranged by the airflow 50 generated by the airflow generation unit 13, or the liquid droplets shifted laterally by the airflow generated by the airflow generation unit 13. 23 can be rearranged by the air flow 50 generated by the fan filter units 3 and 4. Further, the liquid droplets 23 laterally shifted by the airflow generated by the airflow generation unit 13 can be rearranged by the airflow 50 generated by changing the characteristics (particularly direction and strength) of the airflow by the airflow generation unit 13.

  For example, as shown in FIG. 1, the determination as to whether or not the rearrangement is completed is performed by observing the positional relationship between the registration mark 20 a serving as a reference of the position on the substrate 20 to be processed and the plurality of droplets 23. This can be performed based on whether the positional relationship satisfies a predetermined requirement necessary for rearrangement of the plurality of droplets 23. By such real-time observation, the position of the droplet can be rearranged to an appropriate position. The predetermined requirements for the positional relationship are determined in advance at the stage of creating the droplet arrangement pattern. Then, for example, by observing with the observation unit 31, it is determined whether or not the positional relationship between the registration mark 20a and the plurality of droplets 23 satisfies a predetermined requirement. Here, “the positional relationship between the registration mark and a plurality of droplets” does not necessarily mean the positional relationship between the registration mark and all of the droplets. That is, a representative droplet (one or several) is selected from a plurality of droplets, and the positional relationship between the registration mark and the representative droplet is expressed as “the positional relationship between the registration mark and the plurality of droplets”. Can also be considered. In fact, if the lateral shift of the entire plurality of droplets occurs in the same way, no serious problem arises in the rearrangement even if considered as described above.

  In addition, whether or not the rearrangement has been completed is determined by determining the airflow generation requirements (for example, the strength and direction of the airflow and the time during which the airflow is applied) required for the rearrangement of the plurality of droplets. It can also be determined based on whether or not the occurrence requirement is satisfied in advance by experimentally obtaining the same conditions. For example, when an airflow having a certain intensity and direction is applied for a predetermined time, it can be determined that the rearrangement has been completed when the predetermined time has elapsed. In this case, the registration mark as described above becomes unnecessary.

  Then, when it is determined that the rearrangement is completed, the rearrangement work is stopped. The meaning of “stopping the rearrangement work” includes not only stopping the airflow but also performing imprinting without stopping the airflow.

  The pressing pressure of the mold 1 is in the range of 100 kPa to 10 MPa. When the pressure is larger, it is easier to make the surface shapes of the mold 1 and the substrate follow each other, and the resist flow is promoted. Furthermore, when the pressure is high, removal of residual gas, compression, dissolution of the residual gas into the resist, and transmission of He through the quartz substrate are promoted, leading to an improvement in the quality of the resist pattern. However, if the applied pressure is too strong, there is a possibility that the mold 1 and the substrate may be damaged when a foreign object is caught when the mold 1 contacts. Therefore, the pressing pressure of the mold 1 is preferably 100 kPa to 5 MPa, and particularly preferably 100 kPa to 1 MPa. The reason why the pressure is set to 100 kPa or higher is that when imprinting is performed in the atmosphere, when the space between the mold 1 and the substrate is filled with liquid, the pressure between the mold 1 and the substrate is pressurized at atmospheric pressure (about 101 kPa). is there.

  After the mold 1 is pressed to form a resist film, the resist is cured by exposure with light containing a wavelength matched to the polymerization initiator contained in the resist. As a method of releasing after curing, for example, the back surface or outer edge portion of either the mold 1 or the substrate is held, and the back surface or outer edge portion of the other substrate or mold is held, and the holding portion or back surface of the outer edge is held. A method of moving the holding part relative to the direction opposite to the pressing can be mentioned.

  As described above, the nanoimprint method according to the present embodiment includes a combination of a plurality of droplets by rearranging a plurality of droplets and then pressing the concave / convex pattern against the surface of the substrate to which the droplets are applied. A concavo-convex pattern is transferred to a curable resin film. In other words, in the present invention, even if the positions of a plurality of droplets are shifted on the substrate to be processed, the mold can be pressed against the substrate to be processed with an appropriate droplet arrangement, so that uneven film thickness and unfilled defects occur. Can be reduced.

<Design changes>
In the above description, the case where droplets are rearranged using the airflow 50 has been described, but the present invention is not limited to this. For example, as a method of rearranging the droplets, for example, as shown in FIG. 5, a method of moving the droplets by tilting the substrate 20 to be processed by an angle θ using the tilt function of the XY stage 21 ( FIG. 5c).

  In the case where the workpiece substrate 20 is tilted, the determination as to whether or not the rearrangement is completed is performed, for example, as shown in FIG. For example, the magnitude of the angle θ and the tilting direction and the tilting time) can be obtained experimentally under the same conditions before arranging the plurality of droplets 23, and can be performed based on whether or not the tilting requirement is satisfied. . For example, when a certain angle and inclination of a certain direction are given for a predetermined time, it can be determined that the rearrangement is completed when the predetermined time elapses.

  Whether or not the rearrangement has been completed is determined by observing the positional relationship between the registration mark serving as a reference of the position on the substrate to be processed and a plurality of liquid droplets, as described above. It can also be performed based on whether or not a predetermined requirement necessary for the rearrangement of droplets is satisfied.

  When it is determined that the rearrangement is completed, the rearrangement operation is stopped by setting the angle θ to 0 ° (FIG. 5d).

“Second Embodiment of Nanoimprint Method”
Next, a second embodiment of the nanoimprint method will be described. In consideration of the fact that the plurality of droplets are laterally displaced on the substrate to be processed, the nanoimprint method according to the present embodiment places the plurality of droplets in a position away from a predetermined position on the substrate to be processed in advance. It is different from the nanoimprint method of the first embodiment. In other words, the first embodiment is characterized in that the droplet arrangement is corrected after the lateral deviation, but in this embodiment, the first droplet arrangement, which is the previous stage of the lateral deviation, is finally corrected to be appropriate. It is characterized by obtaining a simple droplet arrangement.

FIG. 6 is a schematic diagram showing the steps of the droplet rearrangement method in the present embodiment. In the nanoimprint method of the present embodiment, for example, using an apparatus as shown in FIG. 2, a plurality of droplets 23 are processed after the droplets 23 are arranged and before the concave / convex pattern 16 of the mold 10 contacts the droplets 23. As a result of lateral displacement on the substrate 20, the plurality of droplets 23 are separated from the predetermined position 24 on the processed substrate 20 by a shift amount Δ ₂ so that the plurality of droplets 23 are arranged at the predetermined position 24 on the processed substrate 20. A plurality of droplets 23 are arranged at the positions (FIG. 6a), and the concavo-convex pattern 16 is pressed against the surface of the substrate 20 to which the droplets 23 are applied to form a curable resin film composed of a combination of the plurality of droplets 23. The uneven pattern is transferred. In this case, for example, a plurality of liquid droplets 23 are laterally displaced on the substrate 20 to be processed by an air flow 51 generated when helium is blown into a gap space between the mold 10 and the resist in the apparatus. Is shown at a predetermined position 24 on the substrate 20 (FIG. 6b).

The shifting amount delta _2, for example to reflect the creation of the droplet arrangement pattern. For example, a droplet arrangement pattern considering the shift amount Δ ₂ can be created as follows. First, resist droplets are placed on a substrate in a default droplet arrangement pattern with droplet movement factors (fan, XY stage, gas replacement, etc.) driven under desired conditions (step 1a). On the other hand, resist droplets are arranged on the substrate with a default droplet arrangement pattern without driving the droplet movement factor (step 1b). The actual droplet arrangement patterns created in steps 1a and 1b are compared, and the amount of deviation of each droplet due to the presence of a droplet movement factor is measured (step 2). Based on the shift amount of each droplet by that there is a drop moving factors, to create a corrected droplet arrangement pattern in consideration of the shift amount delta ₂ for canceling the deviation amount (step 3).

  As described above, in the nanoimprint method according to the present embodiment, a plurality of droplets are arranged at positions away from a predetermined position on the substrate to be processed so as to cancel lateral shift of the plurality of droplets on the substrate to be processed. It is characterized by doing. In other words, even in the present invention, even if the positions of a plurality of droplets are shifted on the substrate to be processed, the mold can be pressed against the substrate to be processed with an appropriate droplet arrangement. Can be reduced.

"Method for manufacturing patterned substrate"
Next, an embodiment of a method for producing a patterned substrate (for example, a mold duplicate) will be described. In the present embodiment, a duplicate of the mold 1 is manufactured using the above-described nanoimprint method using an Si mold as a master.

  First, using the nanoimprint method, a pattern-transferred resist film is formed on one surface of the substrate. Next, dry etching is performed using the resist film having the pattern transferred as a mask to form a concavo-convex pattern corresponding to the concavo-convex pattern formed on the resist film on the substrate to obtain a substrate having a predetermined pattern.

  On the other hand, when the substrate has a laminated structure and includes a metal layer on the surface, dry etching is performed using the resist film as a mask, and the concavo-convex pattern corresponding to the concavo-convex pattern formed on the resist film is applied to the metal. Then, the substrate is further dry-etched using the metal thin layer as an etch stop layer to form a concavo-convex pattern on the substrate to obtain a substrate having a predetermined pattern.

  The dry etching is not particularly limited as long as it can form a concavo-convex pattern on the substrate, and can be appropriately selected according to the purpose. For example, ion milling, reactive ion etching (RIE), sputter etching, etc. Is mentioned. Among these, ion milling and RIE are particularly preferable.

  The ion milling method is also called ion beam etching and introduces an inert gas such as Ar into an ion source to generate ions. This is accelerated through the grid, and collides with the sample substrate for etching. Examples of the ion source include a Kaufman type, a high frequency type, an electron impact type, a duoplasmatron type, a Freeman type, an ECR (electron cyclotron resonance) type, and the like.

  Ar gas can be used as a process gas in the ion milling method, and fluorine-based gas or chlorine-based gas can be used as an etchant for RIE.

  As described above, according to the method for manufacturing a patterned substrate of the present invention, since the substrate is etched using the resist film having a concavo-convex pattern and suppressing the occurrence of unfilled defects as a mask, the pattern It is possible to reduce the occurrence of pattern defects in the manufacture of the chemical substrate.

  Examples of the nanoimprint method according to the present invention are shown below.

<Example 1>
As the mold, a quartz mold having a size of 152 mm □ and a thickness of 6.35 mm was used. Further, the quartz mold was subjected to a mold release treatment. The droplet made of the photo-curable resist was arranged on the substrate to be processed so as to be shifted from the predetermined position by (x, y) = (100 μm, 100 μm). After moving the droplets so that the position of the resist droplets was a predetermined position, the mold and the photocurable resist layer were brought into contact with each other. The photoresist layer was then exposed. After reducing the pressure to atmospheric pressure, the mold and the photoresist were peeled from each other. In addition, the details of the used quartz mold, the substrate to be processed, the photocurable resist, the resist droplet moving process, and each process are as follows.

(Quartz mold)
A pedestal region having a surface height of about 20 μm is formed at the center of the quartz mold. The size of the pedestal region is 10 mm □. A line & space pattern is formed in the pedestal region due to the presence of a plurality of space patterns having a depth of 100 nm. The width of the space pattern and the space between the spaces (line width) are 100 nm and 100 nm, respectively.

(Si substrate)
A Si substrate having a diameter of 100 mm, which was surface-treated with a silane coupling agent excellent in adhesiveness with a photocurable resist, was used. The surface treatment was performed by diluting the silane coupling agent with a solvent, applying it to the substrate surface by spin coating, and annealing.

(Photo-curing resist)
A photocurable resist formed by mixing the compound represented by the structural formula 1, Aronics M220, IRGACURE 379 and the fluorine monomer represented by the structural formula 2 in a mass ratio of 48: 48: 3: 1, respectively, was used. .

(Photocurable resist coating process)
A piezo inkjet printer was used. A dedicated 10 pl head was used as the inkjet head. The droplets were arranged in a 10 mm square region at a pitch of 400 μm in a square lattice shape.

(Resist droplet movement process and mold adhesion process)
In order to align the mold and the Si substrate, the mold and the Si substrate were brought close to each other up to 5 mm, and the alignment mark was positioned at a predetermined position while observing the alignment mark with an optical microscope from the back of the mold. . The resist droplets were rearranged in the state of alignment as described above. The rearrangement of the resist droplets was performed by generating an air flow with a fan installed in the imprint apparatus booth. First, an air flow was generated in the −x direction, and the resist droplet was moved −100 μm in the x direction. Next, an air flow was generated in the −y direction, and the resist droplet was moved −100 μm in the y direction. The movement of the droplets was performed while observing with an optical microscope as needed. After the resist droplet was rearranged at a predetermined position, the mold and the resist droplet were brought into close contact with each other.

(Exposure process)
It exposed so that the irradiation amount might be set to 300 mJ / cm < ² > with the ultraviolet light containing a wavelength of 360 nm. A cold filter was installed between the exposure source, the mold and the Si substrate so that the temperature of the mold and the Si substrate did not rise during exposure.

<Example 2>
Example 2 is the same as Example 1 except that the rearrangement of the droplets was performed by the air flow generated by the imprint head.

<Example 3>
The rearrangement of the droplets is the same as that of the first embodiment except that the XY stage is tilted. First, the XY stage was tilted in the first direction, and the resist droplet was moved by −100 μm in the x direction. Then, the XY stage was tilted in the second direction, and the resist droplet was moved by −100 μm in the y direction.

<Comparative Example 1>
Example 1 is the same as Example 1 except that the rearrangement of droplets was not performed.

<Evaluation method>
(Residual film unevenness)
The thickness of the remaining film of the line & space pattern from the center of the Si substrate of the photocurable resist to the vicinity of the resist boundary was measured. By exposing a Si substrate by peeling a part of the pattern area of the photocurable resin by scratching or tape peeling, and measuring the boundary between the peeling area and the pattern area with an AFM (atomic force microscope). The thickness h of the remaining film was measured. About thickness h, arbitrary five places were measured. When the difference between the maximum value hmax and the minimum value hmin (hmax−hmin) of the thickness h is less than 10 nm, the remaining film unevenness did not occur, and when the difference was 10 nm or more, the remaining film unevenness was evaluated.
(Unfilled defect)
The line & space pattern of the photocurable resin obtained in Examples 1 to 3 and Comparative Example 1 was inspected by dark field measurement of a light receiving device (50 to 1,500 times magnification). Specifically, it is as follows. First, it set so that the measurement visual field of a microscope might be set to 2 mm square at 50 times magnification. Next, scanning was performed within the range of the resist pattern formation region, and the presence or absence of imprint defects due to unfilled defects on the Si surface was measured. Unfilled defects were targeted when scattered light that was not found in a normal pattern was detected. The number of occurrences of unfilled defects was counted, and the case where the number of occurrences per 1 cm square was 0 was evaluated as no occurrence of defects, and the case of 1 or more cases was evaluated as occurrence of defects.

<Evaluation results>
Table 1 below summarizes the results of Examples 1 to 3 and Comparative Example 1. From this table, it can be seen that according to the present invention, the occurrence of film thickness unevenness and unfilled defects can be reduced.

DESCRIPTION OF SYMBOLS 1 Nanoimprint apparatus 2 Exterior 3, 4 Fan filter unit 10 Mold 11 Mold holding part 12 Suction port 13 Airflow generation part 16 Uneven pattern 20 Substrate 21 Stage 22 Stage rail 23 Resist droplet 25 Curable resin film 30 Exposure light source 31 Observation Section 32 Droplet application section 40 Transport unit 41 Loading / unloading section B Airflow Δ ₁ Side shift amount Δ ₂ Shift amount

Claims (10)

In the nanoimprint method using a mold having a fine uneven pattern on the surface,
Place a plurality of droplets made of curable resin on the substrate to be processed,
The plurality of droplets are arranged at predetermined positions on the substrate to be processed before the uneven pattern comes into contact with the droplets after the droplets are disposed. Rearrange the droplets of
After the plurality of droplets are rearranged, the concavo-convex pattern is pressed onto the surface of the substrate to be processed which is coated with the droplets, and the concavo-convex pattern is transferred to the curable resin film formed by the combination of the plurality of droplets. Nanoimprinting method characterized by performing.   The nanoimprint method according to claim 1, wherein the plurality of droplets are rearranged by shifting the droplets by an air flow generated in the imprint apparatus.   The nanoimprint method according to claim 2, wherein the air flow is generated by a fan attached to the imprint apparatus.   4. The airflow is generated by an airflow generation unit attached to a mold holding unit for holding the mold and / or a substrate holding unit for holding the substrate to be processed in an imprint apparatus. The nanoimprint method described.   2. The nanoimprint method according to claim 1, wherein the plurality of droplets are rearranged by tilting the substrate to be processed on which the plurality of droplets are arranged to shift the droplets. 3. Observe the positional relationship between the registration marks and the plurality of droplets as a reference of the position on the substrate to be processed,
6. The nanoimprint according to claim 1, wherein the rearrangement of the plurality of droplets is terminated when the positional relationship satisfies a predetermined requirement necessary for rearrangement of the plurality of droplets. Method. Determining the airflow generation requirements necessary for repositioning the plurality of droplets before placement of the plurality of droplets;
The nanoimprint method according to any one of claims 2 to 4, wherein the rearrangement of the plurality of droplets is terminated when the generation requirement is satisfied. Determining the tilt requirement of the substrate required for repositioning the plurality of droplets prior to the placement of the plurality of droplets;
The nanoimprint method according to claim 5, wherein the rearrangement of the plurality of droplets is terminated when the tilt requirement is satisfied. Using a mold having a fine concavo-convex pattern on the surface, a plurality of droplets made of a curable resin are arranged on the substrate to be processed, and the concavo-convex pattern is pressed against the surface of the substrate to be processed coated with the droplets In the nanoimprint method for transferring the concavo-convex pattern to the curable resin film composed of a combination of the plurality of droplets,
After the droplets are arranged and before the concave / convex pattern comes into contact with the droplets, the plurality of droplets are displaced on the substrate to be processed. As a result, the plurality of droplets are arranged at predetermined positions on the substrate to be processed. As described above, the nanoimprint method is characterized by disposing the plurality of droplets at a position away from a predetermined position on the substrate to be processed. A curable resin film having a concavo-convex pattern transferred thereon by the nanoimprint method according to claim 1 is formed on a substrate,
Etching the substrate using the curable resin film as a mask to form a concavo-convex pattern corresponding to the concavo-convex pattern transferred to the curable resin film on the substrate. .