JP2011119447A - Method for measuring release force of transfer material for nano imprint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a release force measuring method by which, in order to obtain information of a release property between a mold with which fine patterns formed and a transfer material, a release force of the transfer material at the time when the fine patterns are transferred to and formed in the transfer material applied on a surface of a substrate to be processed in accordance with a minute mold shape for nano imprint can be easily and quantitatively measured. <P>SOLUTION: The present invention relates to a release force measuring method for measuring a release force of a transfer material for nano imprint applied on a surface of a substrate to be processed, a probe provided in a cantilever of a scanning type probe microscope is inserted into the transfer material, the transfer material is irradiated with ultraviolet rays and photocured, and then an adhesion force between the probe and the photocured transfer material at the time when the probe is pulled out of the photocured transfer material is measured as a release force. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mold release force measuring method for measuring a mold release force of a nanoimprint transfer material applied to a substrate surface which is a workpiece.

  In recent years, especially for semiconductor devices, high speed operation and low power consumption operation are required due to further progress in miniaturization, and high technology such as integration of functions called system LSIs is required. Under such circumstances, the lithography technology that is necessary for producing the pattern of the semiconductor device has become very expensive as the exposure apparatus and the like as the pattern becomes finer, and the price of the mask used therefor also becomes expensive. Yes.

  On the other hand, the nanoimprint method proposed by Chou et al. In Princeton University in 1995 is attracting attention as a fine pattern formation technique having a high resolution of about 10 nm, although the apparatus price and materials used are low (non-patent) Reference 1 and Patent Reference 1).

  In the nanoimprint method, a mold (also referred to as a template, stamper, or mold) with a nanometer-sized concavo-convex pattern formed on the surface in advance is pressed against a transfer material such as a resin that is applied to the substrate surface, which is the workpiece. In this technique, a fine pattern is precisely transferred by being deformed and the material to be processed is processed using the patterned resin as a resist mask. Once the mold is made, the nanostructure can be easily and repeatedly molded, resulting in high throughput and economics, and because it is a nano-processing technology with little harmful waste, not only semiconductor devices in recent years, Application to various fields is expected.

  In such a nanoimprint method, a thermal nanoimprint method in which a concavo-convex pattern is transferred by heat using a thermoplastic resin, or a photo nanoimprint method in which a concavo-convex pattern is transferred by ultraviolet rays using a photocurable resin (see, for example, Patent Document 2) ) Etc. are known. As the resin as the transfer material, a thermoplastic resin is used in the thermal nanoimprint method, and a photocurable resin is used in the optical nanoimprint method. The optical nanoimprint method can transfer patterns at low applied pressure at room temperature, and does not require heating / cooling cycles like the thermal nanoimprint method and does not cause dimensional changes due to mold or resin heat. It is said that it is excellent in terms of sex.

  Molds used in the nanoimprint method are required to have pattern dimension stability, chemical resistance, processing characteristics, and the like. Taking the case of the optical nanoimprint method as an example, generally, quartz glass that transmits ultraviolet rays used for photocuring is used. In the nanoimprint method, the pattern shape of the mold must be faithfully transferred to a resin that is a transfer material. For this purpose, it is necessary to transfer the mold shape to the resin and then release the mold without changing the shape when the mold is released.

  However, a mold made of quartz glass or the like usually has low releasability from a resin that is a pattern transfer material, and the resin adheres to the mold side when the mold is released from the resin on which the transfer pattern is formed. There was a problem that chipped defects were generated in the concavo-convex pattern, and the pattern accuracy was liable to deteriorate. For this reason, as a method for improving the mold releasability between the mold and the resin, for example, a method for improving the releasability by applying and forming a thin film of a release agent such as a fluororesin on the surface of the concave and convex pattern of the mold has been proposed. . On the other hand, development of a resin having good releasability is also underway.

  Therefore, obtaining information on whether the mold unevenness pattern and the transfer material have good releasability is extremely important in determining the quality, yield, and productivity of nanoimprinted products. There is also a strong demand from the viewpoint of developing a good mold or transfer material. Conventionally, as a method for evaluating adhesion in relation to releasability, a sample surface adhesion evaluation method using a cantilever of an atomic force microscope (hereinafter also referred to as AFM) has been proposed (Patent Literature). 3). Alternatively, the AFM probe probe is moved away from the substrate surface and scanned in a non-contact manner, the resist line pattern side surface on the substrate is brought into contact with the probe, and the resist is peeled off by the horizontal force (horizontal load) of the probe. Then, an adhesion force measurement method called DPAT (Direct Peeling method with Atomic force microscope Tip) method for examining adhesion has been proposed (see Non-Patent Document 2).

JP-T-2004-504718 JP 2002-93748 A JP-A-6-241777

S. Y. Chou et. al. , Science, vol. 27 2, p. 85-87, April, 1996. A. Kawai, et al. , Microelectronic Engineering, 83 (2006) 659-662.

  However, the adhesion evaluation method described in Patent Document 3 is a method for measuring the atomic force related to adhesion between a probe having a resist film formed on the surface and the sample surface, It is a method for evaluating the adhesion between the resist film and the sample substrate, and only the averaged adhesion force in the macro region can be measured, so even if this method is applied to the measurement of a transfer material for nanoimprint, There has been a problem that the result of the releasability between the mold and the transfer material in the actual nanoimprint using the mold does not match. The method described in Non-Patent Document 2 is a measurement method related to adhesion between the substrate surface and the resist pattern formed thereon, and a fine pattern on the substrate surface to be measured. When the side of the probe contacts the probe and pressure is applied to the pattern, the resist film itself is sheared by the probe before the pattern is peeled off or peeled off from the substrate, and accurate adhesion data is obtained. There was a problem that it could not be obtained. Furthermore, the above-described conventional method has a problem that many steps are required for preparation such as preparation of a sample for measurement, which is complicated.

  As described above, in the conventional nanoimprint method, there is a problem that a method for quantitatively evaluating the releasability between the mold and the transfer material in forming a fine pattern of several tens of nanometers has not yet been established. In the development of molds or molds, or in the production of nanoimprint products, there has been a strong demand for a method for measuring the release force of the nanoimprint method that can easily obtain the release force between the mold and the transfer material.

  Therefore, the present invention has been made in view of the above problems. That is, the object of the present invention was applied to the surface of a substrate to be processed corresponding to a fine mold shape for nanoimprinting in order to obtain releasability information between a mold having a fine pattern and a transfer material. It is an object of the present invention to provide a release force measuring method capable of easily and quantitatively measuring the release force of a transfer material when a fine pattern is transferred and formed on the transfer material.

  In order to solve the above problems, a release force measuring method according to the invention of claim 1 is a release force measuring method for measuring a release force of a nanoimprint transfer material applied to a surface of a substrate to be processed. After inserting the probe provided on the cantilever of the scanning probe microscope into the transfer material, the transfer material is irradiated with ultraviolet rays to be photocured, and then the probe is removed from the photocured transfer material. The adhesive force between the probe and the photocured transfer material when extracted is used as a release force.

  The mold release force measuring method according to claim 2 is the mold release force measuring method according to claim 1, wherein the surface area of the insertion portion of the probe inserted into the transfer material is obtained in advance. Alternatively, the surface area of the probe is obtained by measuring the shape of the hole after extracting the probe.

  A mold release force measuring method according to a third aspect of the present invention is the mold release force measuring method according to the first or second aspect, wherein the shape and dimensions of the probe inserted into the transfer material are for nanoimprinting. It is substantially the same as one unit of the pattern shape and dimensions of the mold.

  The mold release force measuring method according to the invention of claim 4 is the mold release force measuring method according to any one of claims 1 to 3, wherein a surface of the probe is chemically modified. It is characterized by.

  According to a fifth aspect of the present invention, there is provided a release force measuring method according to the fourth aspect, wherein a silicon oxide film is formed on a surface of the probe, and the chemical modification is performed by a release agent. The release agent is an amphiphilic silane coupling agent, and the chemical modification is formed of a monomolecular film in which the hydrophobic group of the release agent is oriented on the side opposite to the probe side. It is characterized by being.

  A mold release force measuring method according to a sixth aspect of the present invention is the mold release force measuring method according to any one of the first to fifth aspects, wherein a force curve between the probe and the transfer material is obtained. And a step of measuring the viscosity of the transfer material.

  According to the method for measuring the release force of the transfer material for nanoimprints of the present invention, by using the probe provided on the cantilever of the scanning probe microscope, by measuring the release force of the transfer material on the substrate to be processed, The release force of the transfer material corresponding to the nanoimprint mold can be measured by a simple method. Furthermore, the surface area of the probe is obtained by measuring the shape of the hole after removing the probe using a scanning probe microscope in which a probe having a known surface area of the transfer material insertion portion is mounted on the cantilever, By measuring the release force of the transfer material, the release force corresponding to the nanoimprint mold can be quantified by a simple method. Further, by controlling the shape and dimensions of the probe, it is possible to measure the release force at substantially the same shape and size level as the nanoimprint pattern, and it is possible to further improve the reliability of the measured release force. The mold release force measuring method of the present invention has an advantage that it can be measured if there is a small amount (small area or small space) of the sample, and the measuring operation is easy.

  The method for measuring the release force of the nanoimprint transfer material of the present invention can be performed by simplifying the material evaluation of the release agent when the release agent is provided on the mold surface by chemically modifying the probe. When silicon is used as the probe material, a natural oxide film of silicon exists on the surface, so that the probe is in a surface state similar to a quartz glass mold, and the reliability of the release force to be measured is further increased. An effect is produced. Further, by designing the shape of the probe, it is possible to measure the release force in various patterns such as a pillar pattern. Furthermore, it is possible to obtain a force curve between the probe and the transfer material and quantitatively evaluate the viscosity of the transfer material. It is also possible to measure the amount of meniscus when the probe is inserted into the transfer material or when the probe is removed from the photocured transfer material.

  According to the method for measuring the release force of a nanoimprint transfer material of the present invention, the transfer material applied on the substrate to be processed can be monitored, the nanoimprint process management becomes easy, and the quality / step of the imprinted product can be improved. There is an effect that the productivity can be improved.

It is a figure for demonstrating the mold release force measuring method of the transfer material for nanoimprint of this invention, Comprising: It is a cross-sectional schematic diagram of the process of inserting the probe of a cantilever in a transfer material, and pulling out after photocuring. It is a measurement principle figure at the time of using AFM as an example for the mold release force measuring method of the nanoimprint transfer material of the present invention. It is a figure which shows the force curve which acts between the probe of a cantilever and a transfer material. It is a partial expanded sectional view which shows the meniscus angle when inserting the probe of a cantilever in an uncured transfer material, and extracting from a photocured transfer material.

  Hereinafter, the details of the embodiment of the present invention will be described with reference to the drawings.

  The present invention can directly measure the release force when a fine pattern is formed by measuring the release force of a transfer material on a substrate to be processed using a cantilever probe of a scanning probe microscope. .

  FIG. 1 is a schematic cross-sectional view of a process for measuring a release force using a cantilever probe for explaining a method for measuring a release force of a nanoimprint transfer material according to the present invention. FIG. It is a measurement principle figure at the time of using AFM as an example of a scanning probe microscope for a type force measuring method. FIG. 3 is a diagram showing a force curve that acts between the probe of the cantilever and the transfer material. FIG. 4 is a partially enlarged cross-sectional view showing the meniscus angle when the cantilever probe is inserted into an uncured transfer material and when it is extracted from the photocured transfer material. 1-4, the same code | symbol is used when showing the same location.

  In the method for measuring the release force of a transfer material for nanoimprinting of the present invention, a probe provided on a cantilever of a scanning probe microscope is inserted into a transfer material applied and formed on a substrate to be processed as a sample. After the transfer material is photocured, the probe is extracted, and the adhesive force between the probe and the photocured transfer material is measured to obtain a release force. The scanning probe microscope is provided with a sharply pointed probe at the free end of a cantilever probe called a cantilever having a length of 100 μm to 2000 μm made of an elastic body having a predetermined spring constant. In this device, an attractive force such as van der Waals force is applied between the probe tip and the sample surface, and the local shape and physical properties of the sample are measured from the displacement of the cantilever. By imparting appropriate rigidity to the cantilever of the scanning probe microscope, the contact load with the sample can be increased, and the probe can be inserted into a transfer material made of a low-viscosity resin or the like.

An AFM is preferable as an apparatus used in the method for measuring the release force of the nanoimprint transfer material of the present invention. For example, a cantilever type scanning probe microscope (Scanning Probe Microscope; Scanning Tunneling Microscope; STM); It can also be used in other microscopes collectively called SPM).
In the following description, the method for measuring the release force of the transfer material for nanoimprinting of the present invention will be described by taking AFM as an example.

  FIG. 2 is a measurement principle diagram when AFM is used in the method for measuring the release force of the nanoimprint transfer material of the present invention. As shown in FIG. 2, when the sample 13 coated with the transfer material on the substrate to be processed is gradually brought closer to the minute probe 15 having the cantilever 14 structure, an attractive force or a repulsive force is generated between them at a certain distance. The cantilever 14 provided with the probe 15 is distorted. The distortion is detected by the optical sensor 23 by the change in the reflection angle of the laser beam 22 applied to the back surface of the cantilever 14. The original function of the AFM is to control the distance between the probe 15 and the sample 13 so that the amount of distortion of the cantilever 14 is constant when the probe 15 is scanned on the sample 13 surface, and the surface of the sample 13 is scanned. (X direction, Y direction) and control of the distance between the probe 15 and the sample 13 (Z direction) are performed by the piezo scanner 24, and an image of the surface of the sample 13 is analyzed by analyzing the voltage applied to each scanner. Is obtained. In the method for measuring the release force of the transfer material for nanoimprinting of the present invention, it is not always necessary to obtain the distribution of the surface shape and the like, and when the probe 15 is moved to a predetermined position on the sample 13 to be measured, The release force of the transfer material described is measured.

  FIG. 1 is a process cross-sectional view for explaining in more detail the process of inserting a probe into a transfer material and pulling it out after photocuring when performing the method for measuring the release force of the transfer material for nanoimprinting of the present invention using AFM. It is a schematic diagram. As shown in FIG. 1A, a sample 13 is prepared by applying a transfer material 12 for measuring a releasing force on a substrate 11 to be processed, and the sample 13 is gradually formed into a minute probe 15 having a cantilever 14 structure. Move closer. When the distance between the probe 15 and the sample 13 approaches several nanometers to several tens of nanometers, an inter-surface force such as van der Waals force acts between them, an attractive force acts first, and then a repulsive force acts. In FIG. 1A, the cross-sectional shape of the probe 15 provided on the cantilever 14 is such that the side contacting the cantilever 14 is a wide triangular base, and the sample 13 side is a tip having a very small rectangular needle. It consists of

  Further, the sample 13 is pushed up to bring the probe 15 into contact with the transfer material 12 of the sample 13, and then the probe 15 is inserted into the transfer material 12 (FIG. 1B). Usually, since the transfer material 12 is a low-viscosity resin, the probe 15 is inserted into the transfer material 12 due to the rigidity of the cantilever 14. The tip of the probe 15 inserted into the transfer material 12 is preferably inserted as close as possible to the substrate 11 to be processed in the transfer material 12 so as to be in the same state as when the mold is used.

  Next, as shown in FIG. 1C, in a state where the probe 15 is inserted into the transfer material 12, the transfer material 12 is irradiated with ultraviolet rays 16 to polymerize and cure the low-viscosity resin, and then photocured. The transfer material 17 is used. Irradiation with ultraviolet rays 16 is preferably performed with a slight angle around the insertion portion of the probe 15 so that an unirradiated portion is not formed behind the cantilever 14. The irradiation conditions such as the wavelength of the ultraviolet rays 16 and the irradiation time are preferably the same as in the case of actual nanoimprinting using a mold.

  Next, as shown in FIG. 1D, after the transfer material 12 is photocured, the sample 13 is moved away from the probe 15 in the opposite direction, and the probe 15 is extracted from the photocured transfer material 17. Then, the suction force acts, and the probe 15 is bent downward. When the force due to the deflection exceeds the adsorption force, the cantilever 14 returns to the horizontal position. A minute extraction pattern 18 (hole) is formed by the photocured transfer material 17 on the trace of the probe 15 extracted. The adhesion force between the probe 15 and the photocured transfer material 17 at the time of extraction is measured to obtain a release force.

  The deflection of the cantilever 14 is detected by an optical sensor based on a change in the reflection angle of the laser light applied to the back surface of the cantilever 14, and the amount of deflection of the cantilever 14 is measured. Control of the distance between the sample 13 and the probe 15 (Z direction) is performed by a piezo scanner. From the cantilever deflection and the cantilever spring constant, the hook force F = kx (k is the cantilever spring constant [N / m], x is the cantilever deflection [m]) and the adhesion force F is obtained. In FIG. 3, the horizontal axis represents the distance between the sample 13 and the probe 15, the vertical axis represents the force (force: F) acting between the sample 13 and the probe 15, and the deflection of the cantilever 14 is shown in FIG. Plotted (solid line in FIG. 3). The adhesion force is read from the force curve (the maximum value on the attractive side is the adhesion force F), and this measured adhesion force is used as the release force of the transfer material 12 when a fine pattern is formed.

  In the nanoimprint transfer material release force measurement method of the present invention, it is preferable that the surface area of the insertion portion of the probe 15 inserted into the transfer material 12 is known. By obtaining the surface area of the insertion portion of the probe 15 in advance, a release force per unit area can be obtained, and different transfer materials, release agents, or release forces between molds can be compared. It becomes easy. Alternatively, the surface area of the insertion portion of the inserted probe 15 may be obtained by measuring the shape of the hole (extraction pattern 18) after extracting the probe 15.

  In the above description of FIGS. 1 to 3, the case where the release force is measured by moving the sample 13 side is described. However, in the release force measurement method of the present invention, the release side is moved by moving the probe 15 side. Force may be measured. Although it depends on the apparatus configuration of the scanning probe microscope, the side to be moved in the measurement is not particularly limited.

(Probe)
As the material of the probe 15 used in the method for measuring the release force of the nanoimprint transfer material of the present invention, a probe of a conventionally used material can be applied. That is, as the material of the probe 15, silicon, silicon nitride, silicon oxide, silicon carbide, or the like is used. When silicon is used as the probe material, a natural oxide film of silicon exists on the surface, so that the probe is in a surface state close to a quartz glass mold, and the reliability of the obtained release force value is increased. An effect is produced. Also, a probe in which a methyl group or the like is chemically modified on the surface of the probe material can be used.

  As the shape of the probe 15 used in the present invention, it is possible to use a fine probe conventionally used in which the cross section of the tip portion has a triangular shape and the most distal portion has a curvature radius. As shown in the schematic cross-sectional view, it is more preferable to use a probe in which the upper end side of the probe 15 attached to the cantilever 14 has a wide base portion and a cross section in contact with the sample has a rectangular tip portion. This is because by setting the tip of the probe to the same shape as the pattern of the nanoimprint mold, the measured release force is closer to the case where an actual mold is used, and the reliability is improved. By designing the shape of the tip of the probe 15 inserted into the transfer material 12, it is possible to measure the mold release force in various patterns such as a rectangular parallelepiped, cube, cylinder (pillar pattern), and prismatic shape. It becomes. It is also possible to use a truncated cone with a slight angle at the tip of the probe corresponding to the pattern of the mold or a truncated pyramid shaped probe.

  The probe 15 used in the present invention can measure the releasing force at the same dimensional level as the pattern of the nanoimprint mold, and the shape and dimension of the probe 15 inserted into the transfer material 12 is the pattern of the nanoimprint mold. By making it substantially the same as one unit of shape and size, the reliability of the release force obtained by measurement can be further increased.

  In the release force measuring method of the present invention, since the probe 15 is in direct contact with the transfer material 12, the probe is easily worn according to the frequency of use of the probe 15. As a method for reducing the wear of the probe 15, it is preferable to perform measurement after hydrophobizing the tip surface of the probe 15 to improve the wear resistance of the tip of the probe 15. As the hydrophobic treatment method, for example, a chemical modification treatment with an organic compound such as a self-assembled monolayer or a surface modification treatment with fluorine plasma can be used.

(Transfer material)
The photo-curing resin as the transfer material 12 is applied to the substrate 11 to be faithfully transferred, adherence, low viscosity, releasability, photo-curing property, mechanical strength, resolution. Characteristics such as sex are required. As the transfer material 12 for measuring the releasing force in the present invention, a newly developed photo-curing resin or a conventionally known photo-curing resin can be applied and is not particularly limited. Conventionally known photocurable resins include, for example, acrylic resins, bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, aliphatic glycidyl ether compounds, alicyclic epoxy resins, oxetane resins, Examples include resins such as vinyl monomers, cyclic ethers, and vinyl ethers.

(Evaluation of release agent)
The method for measuring the release force of the transfer material for nanoimprinting of the present invention can be performed by simplifying the material evaluation of the release agent when the release agent is provided on the mold surface by chemically modifying the probe 15. For example, a mold release agent such as a silane coupling agent is chemically modified at the tip of the probe 15, the probe 15 is inserted into a photocurable resin applied and formed on the substrate 11 to be processed, and the probe 15 is photocured. Without using an actual mold by calculating the force curve when the mold is extracted, measuring the release force when a release agent is used, and comparing it with the release force when no release agent is used The material evaluation of the release agent can be simplified.

  In order to chemically modify the probe 15 with a release agent such as a silane coupling agent, at least the surface of the probe 15 needs to be a silicon oxide film or a metal oxide film. When a silicon probe is used, Is preferable because a natural oxide film of silicon is formed on the surface. As the mold release agent for chemically modifying the probe 15, an amphiphilic silane coupling agent that is easy to chemically modify and has a large mold release effect is preferable.

Specific examples of the hydrophilic group possessed by the silane coupling agent include, for example, Si—OCH ₃ , Si—OC ₂ H ₅ , Si—OH, Si—OCl, in the portion bonded to the probe side in the molecule. Those having a functional group such as When a highly hydrophilic functional group is present at the end of the release agent molecule, the molecule is adsorbed on the probe surface with the reactive end facing the probe side and the hydrophobic organic chain facing the outside. These functional groups are thought to adsorb by causing a chemical reaction with oxygen in the oxide film of the probe. Since molecular adsorption requires a chemical reaction between the probe surface and the terminal functional group, once the probe surface is covered with organic molecules and a monomolecular film is formed, the molecular Adsorption does not occur. As a result, an organic monomolecular film in which molecules are closely gathered and aligned is formed. An example of such a monomolecular film is a Langmuir Blodget film (LB film), and the LB film can be formed by a conventionally known method. The LB film can be formed by a conventionally known method. Further, as a normal method for treating a silane coupling agent, a probe is immersed in a silane coupling agent solution, treated with water vapor, and then heated. Thereafter, it may be washed with a solvent to remove excess silane coupling agent to form a monomolecular film, or a monomolecular film may be formed on the probe by a vapor phase method.

Examples of the hydrophobic group possessed by the amphiphilic silane coupling agent include an alkyl group represented by CH ₃ (CH ₂ ) _n —, a fluoromethyl group represented by CF ₃ (CF ₂ ) _n —, and an epoxy group. (N = 0, 1,...).

  In the present invention, the film thickness of the release agent layer formed on the surface of the probe 15 is determined by the type of the monomolecular film, but is usually in the range of about 1 nm to 5 nm. The film thickness can be measured by AFM.

  As described above, since the tip of the probe 15 of the cantilever of the scanning probe microscope is extremely small, the adhesive force is obtained from the force curve measured in the micro area of several tens of nanometers to obtain the mold release force. The mold release force can be evaluated and inspected, and the mold release agent application state of the mold can be managed by setting a predetermined mold release force.

(Measurement of viscosity of transfer material)
In the method for measuring the release force of the nanoimprint transfer material according to the present invention, a step of measuring the viscosity of the transfer material 12 by obtaining a force curve between the probe 15 provided on the cantilever 14 of the scanning probe microscope and the transfer material 12. Can also be included. The measurement of the viscosity of the transfer material 12 using a scanning probe microscope can be performed by a conventionally known measurement method. Using a measurement mode generally called a contact mode, the sample 13, the cantilever probe 15, This is obtained by performing a modulation of the force acting between the two and analyzing the response of the modulation of the force. The force between the sample 13 and the probe 15 is modulated by relatively vibrating the sample 13 and the probe 15, and the response is detected as a vibration signal as a displacement signal based on viscoelasticity. It can be measured from the amplitude and phase of 15 vibrations. Elasticity can be measured from the change in amplitude of vibration, and viscosity can be measured from the change in phase of vibration. As a characteristic of the transfer material 12, low viscosity is preferable from the viewpoints of applicability and mold application pressure.

(Measurement of meniscus angle of transfer material)
In the method for measuring the release force of the nanoimprint transfer material according to the present invention, the probe 15 provided on the cantilever 14 of the scanning probe microscope is inserted into the transfer material 12 and cured after being irradiated with light, and then extracted. From the above, it is possible to include a step of measuring the meniscus angle as the meniscus amount of the transfer material 12. FIG. 4A is a partially enlarged cross-sectional view when the probe 15 is inserted into the uncured transfer material 12, and shows a meniscus angle θ _1. FIG. 4B is a photo-curing of the probe 15. FIG. 6 is a partially enlarged cross-sectional view when the probe 15 is pulled out from the transfer material 17 after it has been performed, and shows a meniscus angle θ ₂ . By measuring the meniscus angles θ ₁ and θ ₂ , it is possible to investigate the influence of the surface tension due to the meniscus acting between the cantilever probe 15 and the transfer material 12; 17.

According to the method for measuring the release force of a nanoimprint transfer material of the present invention, the transfer material applied on the substrate to be processed can be monitored, the nanoimprint process management becomes easy, and the quality / step of the imprinted product can be improved. Distillation / productivity can be improved.
Hereinafter, the present invention will be described in detail by way of examples.

Example 1
The actual nanoimprint mold is a quartz glass mold having a pillar pattern with a pattern size of 40 nm in diameter, a pitch of 80 nm, and a height of 200 nm.
First, using one basic unit of the pillar pattern, a cantilever provided with a silicon probe having a cylindrical shape with a tip portion having a diameter of 40 nm and a height of 200 nm was prepared. On the other hand, a photocurable resin PAK-01 (manufactured by Toyo Gosei Kogyo Co., Ltd.) was applied as a transfer material onto a 10 mm square silicon wafer substrate by spinner coating to form a 200 nm thick coating film, which was used as a sample.

Next, an AFM (SPA400 / SPI4000: manufactured by SII Nano Technology) was used as a scanning probe microscope, the above sample was placed, then the AFM piezo scanner was moved upward, and the cantilever probe was not moved. After being inserted into the cured photocurable resin to a depth of 150 nm, the photocurable resin is irradiated with ultraviolet rays from a high pressure mercury lamp (the ultraviolet irradiation amount is 10 mJ / cm ³ ) to polymerize and cure the photocurable resin. It was.

Next, the piezo scanner was moved downward, the cantilever probe was extracted from the photo-curing resin polymerized and cured with ultraviolet rays, and a 40 nm diameter pillar pattern was transferred and formed on the photo-curing resin of the sample. The adhesion force with the photocured transfer material when the probe measured by the AFM was extracted was a release force of 15 nN, and this value was used as the mold release force when forming the pattern of the photocurable resin. Furthermore, 7.9 × 10 ⁻⁴ nN / nm ² was obtained as a release force per unit area from the surface area (1.884 × 10 ⁴ nm ² ) of the probe inserted in the photocurable resin. .
By using the mold release force measuring method of the present example, it was possible to measure the mold release force with a sample having a small area at the same shape and dimensional level as the nanoimprint pattern.

(Example 2)
As a release agent for the amphiphilic silane coupling agent, a solution was prepared by diluting OPTOOL DSX mainly composed of a fluorine-substituted alkyl group-containing organosilicon compound with a dedicated diluent. This solution is spread on the water surface, a monomolecular film is formed on the surface of the probe used in Example 1 by the LB method, heated at 80 ° C. for 5 minutes, and then allowed to stand at room temperature in the atmosphere for 1 hour. And dried to form a release layer on the probe surface.

  Next, in the same manner as described above, a photocurable resin PAK-01 (manufactured by Toyo Gosei Kogyo Co., Ltd.) was applied as a transfer material onto a 10 mm square silicon wafer substrate to form a coating film having a thickness of 200 nm as a sample.

Next, the AFM piezo scanner is moved upward, the cantilever probe is inserted into the uncured photo-curing resin to a depth of 150 nm, and then irradiated with ultraviolet light with a high-pressure mercury lamp (the ultraviolet irradiation amount is 10 mJ / cm ³ ), and the photocurable resin was polymerized and cured.

Next, the piezo scanner was moved downward, the cantilever probe was extracted from the photo-curing resin polymerized and cured with ultraviolet rays, and a 40 nm diameter hole pattern was transferred and formed on the photo-curing resin of the sample. The adhesion force with the photocured transfer material when the probe is removed is measured by AFM, and a release force of 1.2 nN is obtained, and the release force per unit area is 0.6 × 10 ⁻⁴ nN. / Nm ² .
From the comparison with Example 1, it was found that the release force per unit area was reduced to 1/10 or less by using the release agent of this example compared to the case without using the release agent. .

DESCRIPTION OF SYMBOLS 11 Substrate 12 Transfer material 13 Sample 14 Cantilever 15 Probe 16 Ultraviolet 17 Photocured transfer material 18 Pattern 21 Laser light source 22 Laser light 23 Optical sensor 24 Piezo scanner 25 X and Y axis scanning system 26 Z axis servo system 27 Computer 28 Preamplifier 29 Monitor

Claims (6)

A mold release force measuring method for measuring a mold release force of a nanoimprint transfer material applied to a surface of a substrate to be processed,
After inserting the probe provided on the cantilever of the scanning probe microscope into the transfer material, the transfer material is irradiated with ultraviolet rays to be photocured,
Next, a mold release force is obtained by measuring an adhesive force between the probe and the photocured transfer material when the probe is extracted from the photocured transfer material. Force measurement method.   The surface area of the insertion portion of the probe inserted into the transfer material is obtained in advance, or the surface area of the probe is obtained by measuring the shape of the hole after the probe is extracted. The mold release force measuring method according to claim 1.   3. The mold release according to claim 1, wherein a shape and a dimension of the probe inserted into the transfer material are substantially the same as a unit of a pattern shape and a dimension of the nanoimprint mold. Force measurement method.   The mold release force measuring method according to any one of claims 1 to 3, wherein a surface of the probe is chemically modified.   A silicon oxide film is formed on the surface of the probe, and the chemical modification is performed by a mold release agent. The mold release agent is an amphiphilic silane coupling agent, and the chemical modification is performed by using the mold release agent. 5. The mold release force measuring method according to claim 4, wherein the release force measuring method is formed of a monomolecular film in which a hydrophobic group is oriented on the side opposite to the probe side.   The mold release force measurement according to any one of claims 1 to 5, further comprising a step of obtaining a force curve between the probe and the transfer material and measuring a viscosity of the transfer material. Method.

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