JP5329661B2 - Imprint mold and manufacturing method thereof - Google Patents

Abstract

Disclosed is a mold for imprinting, which comprises a surface layer having a fine pattern formed on a surface thereof and a supporting layer supporting both the aforementioned surface and the rear surface opposed to the aforementioned surface of the surface layer, wherein the surface layer comprises a side-chain crystalline polymer. Also disclosed is a method for manufacturing a mold for imprinting, which comprises the steps of: laminating a surface layer comprising a side-chain crystalline polymer on a supporting layer; pressurizing a surface of the surface layer by means of a master mold having a fine pattern formed thereon at a temperature equal to or higher than the melting point of the side-chain crystalline polymer; and decreasing the temperature of the surface layer to a temperature lower than the melting point of the side-chain crystalline polymer, and removing the master mold from the surface of the surface layer, thereby transferring the fine pattern of the master mold to the surface of the surface layer.

Description

  The present invention relates to an imprint mold and a method for manufacturing the same.

  Recently, imprint lithography, which can efficiently form a fine pattern on the surface of a substrate to increase throughput, has attracted attention. In imprint lithography, a film made of a curable resin composition is formed on the surface of a substrate, the surface of the film is pressed with a mold to transfer a fine pattern of the mold, and the film on which the fine pattern is transferred is cured to form a fine film. This is a method for forming a pattern on a substrate surface.

  Since the fine pattern formed by imprint lithography corresponds to the fine pattern of the mold to be used, the importance of the mold in imprint lithography is high. In order to prevent the resin composition from adhering, the mold fine pattern is usually subjected to a mold release treatment using a fluorine-containing self-assembled monolayer or the like.

  However, when imprint lithography is repeatedly performed, there is a problem that the mold release process applied to the fine pattern deteriorates (for example, see Non-Patent Document 1). When imprint lithography is performed using a mold whose mold release process has deteriorated, not only the transfer accuracy is lowered, but the mold itself is also damaged.

  When a re-molding process is performed on the fine pattern of the mold, high throughput, which is one of the features of imprint lithography, is impaired. The fine pattern of the mold is usually formed by electron beam (EB) lithography. In EB lithography, the more complex the pattern is, the more time it takes to form it. Therefore, if the mold is damaged, it cannot be easily reproduced. Therefore, there is a need for development of a mold that can be easily reproduced without the need for mold release processing or re-mold release processing.

Y.Tada, H.Yoshida, and A.Miyauchi, J.Photopolym.Sci.Technol., 20, p545,2007

  An object of the present invention is to provide an imprint mold having high releasability and easily reproducible, and a method for producing the same.

  The imprint mold of the present invention comprises a surface layer having a fine pattern on the surface, and a support layer that supports a back surface opposite to the surface of the surface layer, and the surface layer is made of a side chain crystalline polymer. .

  The method for producing an imprint mold of the present invention includes a step of laminating a surface layer made of a side chain crystalline polymer on a support layer, and the surface of the surface layer is a master mold having a fine pattern, Pressurizing at a temperature equal to or higher than the melting point of the crystalline polymer, and then setting the temperature of the surface layer to a temperature lower than the melting point of the side chain crystalline polymer, peeling the master mold from the surface of the surface layer, and Transferring the pattern to the surface of the surface layer.

  According to the imprint mold of the present invention, since the fine pattern of the mold is made of a side chain crystalline polymer having excellent releasability, it is not necessary to perform a release treatment on the fine pattern of the mold. Therefore, it is not necessary to perform a re-molding process on the mold fine pattern as in the prior art, and the high throughput of the imprint lithography is not impaired.

  According to the method for producing an imprint mold of the present invention, a fine pattern of a mold is formed by thermally imprinting a master-type fine pattern on a side chain crystalline polymer. Since the thermal imprint on the side chain crystalline polymer can be performed at a relatively low temperature, the thermal imprint can be efficiently performed in a short time to obtain the mold of the present invention. In addition, the mold can be easily reproduced by repeatedly using the master mold.

It is a schematic side view which shows one Embodiment concerning the mold for imprint of this invention. (A)-(d) is process drawing which shows the manufacturing method of the mold for imprint shown in FIG. (A)-(d) is process drawing which shows one Embodiment which manufactures a microstructure using the mold for imprint shown in FIG. It is a scanning electron micrograph of the imprint mold obtained in the example.

  Hereinafter, an embodiment of the imprint mold of the present invention will be described in detail with reference to FIG. As shown in the figure, an imprint mold 10 according to this embodiment includes a surface layer 1 and a support layer 5.

  The surface layer 1 is made of a side chain crystalline polymer. The side chain crystalline polymer is a polymer that crystallizes at a temperature below the melting point and exhibits fluidity at a temperature above the melting point. That is, the side chain crystalline polymer reversibly causes a crystalline state and a fluid state in response to a temperature change.

  The surface layer 1 made of the side chain crystalline polymer has a fine pattern 2 formed on the surface 1a thereof, and the fine pattern 2 is also made of a side chain crystalline polymer. The side chain crystalline polymer in the crystalline state has high releasability. Therefore, the fine pattern 2 also has high releasability, and therefore it is not necessary to perform a conventional release treatment on the fine pattern 2.

  The melting point means a temperature at which a specific portion of the polymer originally aligned in an ordered arrangement becomes disordered by an equilibrium process, and is measured by a differential thermal scanning calorimeter (DSC) at 10 ° C./min. It is a value obtained by measuring under conditions. The mold 10 is used at a temperature below the melting point at which the side chain crystalline polymer is in a crystalline state. Therefore, the melting point is preferably 30 ° C. or higher, and more preferably 50 to 60 ° C.

  On the other hand, if the melting point is too low, the temperature range in which the mold 10 can be used becomes narrow, which is not preferable. The fine pattern 2 of the mold 10 is formed by thermal imprinting as will be described later. Therefore, if the melting point is too high, it is difficult to perform thermal imprinting, which is not preferable. The melting point can be arbitrarily set to a predetermined value by changing the composition of the side chain crystalline polymer.

  As the composition of the side chain crystalline polymer, for example, 20 to 100 parts by weight of (meth) acrylate having a linear alkyl group having 16 or more carbon atoms and (meth) acrylate 0 having an alkyl group having 1 to 6 carbon atoms. Examples include a polymer obtained by polymerizing ˜70 parts by weight and 0-10 parts by weight of a polar monomer.

  Examples of the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms include 16 to 16 carbon atoms such as cetyl (meth) acrylate, stearyl (meth) acrylate, eicosyl (meth) acrylate, and behenyl (meth) acrylate. (Meth) acrylate having 22 linear alkyl groups can be mentioned. Examples of the (meth) acrylate having 1 to 6 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) ) Acrylate, hexyl (meth) acrylate and the like. Examples of the polar monomer include carboxyl group-containing ethylenically unsaturated monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid; 2 -Hydroxyethyl (meth) acrylate, 2- Mud hydroxypropyl (meth) acrylate, 2-hydroxyhexyl (meth) ethylenically unsaturated monomer having a hydroxyl group such as acrylate and the like, which may be used alone or in combination.

  The polymerization method is not particularly limited, and for example, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method and the like can be employed. For example, when the solution polymerization method is employed, the monomer can be polymerized by mixing the monomer exemplified above in a solvent and stirring at about 40 to 90 ° C. for about 2 to 10 hours.

  The side chain crystalline polymer has a weight average molecular weight of 100,000 or more, preferably 400,000 to 800,000. If the weight average molecular weight is too small, the strength of the fine pattern 2 may be lowered and easily damaged. On the other hand, if the weight average molecular weight is too large, even if the side chain crystalline polymer is heated to a temperature equal to or higher than the melting point, it becomes difficult to exhibit fluidity, and thus thermal imprinting becomes difficult. The weight average molecular weight is a value obtained by measuring a side chain crystalline polymer by gel permeation chromatography (GPC) and converting the obtained measurement value to polystyrene.

  The thickness of the surface layer 1 is suitably about 0.01 to 1,000 μm. The thickness of the surface layer 1 means the thickness at which the distance between the front surface 1a and the back surface 1b opposite to the front surface 1a is the largest. Further, the fine pattern 2 is preferably a nano to micrometer scale. The shape of the fine pattern 2 is not particularly limited, and a desired one can be adopted.

On the other hand, the support layer 5 supports the back surface 1 b of the surface layer 1 and imparts rigidity to the mold 10. Examples of the material constituting the support layer 5 include silicon, silicone, and (SiO ₂ ) glass. The thickness of the support layer 5 is suitably about 10 to 1,000 μm.

  The surface 5a of the support layer 5 that supports the surface layer 1 is preferably subjected to a surface treatment. Thereby, the surface 5a is roughened and the adhesiveness of the support layer 5 and the surface layer 1 can be improved. Examples of the surface treatment include corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, and primer treatment.

  Here, the surface layer 1 made of the side chain crystalline polymer usually has UV transparency. When imprint lithography is performed on the UV curable resin composition, the support layer 5 is preferably made of a material having UV transparency. Thereby, since the mold 10 as a whole has UV transparency, the UV curable resin composition can be irradiated with UV through the mold 10.

  Next, the manufacturing method of the mold 10 will be described in detail with reference to FIG. As shown in FIG. 2A, first, the surface layer 1 made of a side chain crystalline polymer is laminated on the support layer 5. The surface 5a of the support layer 5 on which the surface layer 1 is laminated is preferably roughened by surface treatment in order to improve adhesion with the surface layer 1. The lamination is performed by applying a coating solution obtained by adding the side chain crystalline polymer to a solvent on the support layer 5 and drying it.

  The application can be generally performed by a knife coater, a roll coater, a calendar coater, a comma coater or the like. Further, depending on the coating thickness and the viscosity of the coating solution, a gravure coater, a rod coater, a spin coater or the like can be used.

  The surface layer 1 can be laminated by laminating the surface layer 1 formed into a sheet shape or a film shape by extrusion molding or calendering on the support layer 5 in addition to the above application.

After laminating the surface layer 1 on the support layer 5, as shown in FIG. 2 (b), the master mold 20 is disposed above the surface layer 1. The material constituting the master mold 20 is preferably a material having low affinity for the side chain crystalline polymer, and examples thereof include silicon, silicone, and (SiO ₂ ) glass.

  A fine pattern 21 is formed on the surface 20 a of the master mold 20 facing the surface 1 a of the surface layer 1. The reverse pattern of the fine pattern 21 becomes the fine pattern 2 of the mold 10. Therefore, the fine pattern 21 has a shape opposite to the desired fine pattern 2. The fine pattern 21 is preferably a nano to micrometer scale, and can be formed by EB lithography.

  The master mold 20 is moved in the direction of arrow A, and the surface 1a of the surface layer 1 is pressurized with the master mold 20 as shown in FIG. This pressurization is performed at a temperature equal to or higher than the melting point of the side chain crystalline polymer. Thereby, the said side chain crystalline polymer will be in a fluid state, and the thermal imprint which transfers the fine pattern 21 of the master type | mold 20 to the surface 1a of the surface layer 1 will be attained.

  The pressurization temperature is preferably a temperature of the melting point of the side chain crystalline polymer + 10 ° C. to the melting point + 30 ° C. Thereby, the said side chain crystalline polymer will be in an appropriate fluid state, the transcription | transfer precision by the master type | mold 20 will improve, and the thermal imprint at a comparatively low temperature will be achieved. On the other hand, when the pressurization temperature is too low, the flow state of the side chain crystalline polymer is lowered, and there is a possibility that the transfer accuracy by the master mold 20 is lowered. On the other hand, if the pressurization temperature is too high, the side-chain crystalline polymer is heated more than necessary, which is economically disadvantageous because it requires a lot of heat energy.

  For adjusting the pressurizing temperature, for example, a heating means such as a heater is disposed on the back surface 20b opposite to the front surface 20a of the master mold 20, and the surface temperature of the fine pattern 21 is heated to a predetermined temperature by the heating means. The atmospheric temperature can be adjusted to a temperature equal to or higher than the melting point of the side chain crystalline polymer. As other pressurization conditions, a pressure of about 0.1 to 100 MPa and a pressurization time of about 5 to 300 seconds are preferable.

  After pressurizing the surface 1a of the surface layer 1 with the master mold 20, the temperature of the surface layer 1 is kept below the melting point of the side-chain crystalline polymer using a cooling means such as a fan while maintaining this state. Cooling. Thereby, the said side chain crystalline polymer will be in a crystalline state.

  Then, as shown in FIG. 2D, the master mold 20 is moved in the direction of arrow B, and the master mold 20 is peeled from the surface 1a of the surface layer 1 formed of the crystalline side chain crystalline polymer. At this time, the side-chain crystalline polymer in the crystalline state has high releasability as described above. Therefore, the master mold 20 can be peeled off from the surface layer 1 without performing the mold release process on the fine pattern 21 of the master mold 20, and the productivity can be increased.

  When the master mold 20 is peeled off from the surface layer 1, the fine pattern 21 of the master mold 20 is transferred to the surface 1a of the surface layer 1, and the mold 10 having the fine pattern 2 opposite to the fine pattern 21 is obtained. Furthermore, if each process described above is repeated using the master mold 20, the mold 10 can be easily reproduced.

  Next, an embodiment in which a microstructure is manufactured using the mold 10 will be described in detail with reference to FIG. 3 by taking as an example a case where a UV curable resin composition is used as the curable resin composition. As shown in FIG. 3A, first, a film 52 is formed on the surface of the substrate 51.

As a material constituting the substrate 51, for example, silicon, (SiO ₂ ) glass, etc., polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, Examples include synthetic resins such as ethylene polypropylene copolymer and polyvinyl chloride. The substrate 51 preferably has flexibility, and the thickness thereof is, for example, about 50 to 300 μm, preferably about 100 to 150 μm.

  The film 52 is made of a UV curable resin composition. The UV curable resin composition is cured by being irradiated with UV (ultraviolet rays), and various known ones can be adopted. For example, the coating film 52 may be formed by adding a UV curable resin composition to a predetermined solvent to obtain a coating solution, coating the coating solution on the surface of the substrate 51, and drying the coating solution. The application can be performed, for example, by spin coating, slit coating, spray coating, roller coating, or the like. The thickness of the uncured film 52 is, for example, about 0.01 to 1000 μm, preferably about 0.01 to 500 μm.

  After the film 52 is formed on the surface of the substrate 51, the mold 10 is disposed above the film 52 as shown in FIG. This arrangement is performed so that the fine pattern 2 of the mold 10 faces the coating 52. Next, the mold 10 is moved in the direction of arrow C, and the surface of the film 52 is pressurized with the mold 10 as shown in FIG. Thereby, the fine pattern 2 of the mold 10 is transferred to the film 52.

  As pressurization conditions, the pressure is about 0.1 to 100 MPa, and the pressurization time is about 5 to 300 seconds. Curing of the film 52 onto which the fine pattern 2 has been transferred is performed by irradiating the film 52 in a state where the surface of the film 52 is pressed with the mold 10, that is, in the state shown in FIG.

  The UV irradiation direction is not particularly limited as long as the coating 52 can be irradiated with UV. That is, when the substrate 51 has UV transparency, the coating 52 may be irradiated with UV from the back side of the substrate 51. Further, when the support layer 5 of the mold 10 is made of a material having UV transparency, the entire mold 10 has UV transparency as described above. Can be irradiated with UV.

  Next, as shown in FIG. 3 (d), the mold 10 is moved in the direction of arrow D to peel the mold 10 from the cured coating 53. At this time, the fine pattern 2 of the mold 10 is not subjected to release treatment, but the fine pattern 2 has high release properties for the above-described reason, and therefore the load applied to the cured film 53 at the time of peeling is small. Therefore, when the mold 10 is peeled from the cured film 53, the microstructure 50 composed of the cured film 53 to which the fine pattern 2 is transferred with excellent accuracy and the substrate 51 is obtained. In addition, as thickness of the cured film 53, it is 0.01-1000 micrometers, for example, Preferably it is about 0.01-500 micrometers.

  In the obtained fine structure 50, the remaining film 54 is removed by, for example, oxygen reactive ion etching, and the surface of the substrate 51 is exposed between the adjacent cured films 53 and 53, and then the cured film 53 is used as a mask. Etching can be performed, or aluminum or the like can be lifted off and used for wiring or the like.

  In the above embodiment, the UV curable resin composition is described as an example of the curable resin composition. However, as another curable resin composition, for example, a thermoplastic resin composition such as polymethyl methacrylate (PMMA) is used. Things can also be used. Moreover, although the said embodiment demonstrated the case where hardening of the film | membrane with which the fine pattern was transcribe | transferred in the state pressurized with the mold, hardening of the said film | membrane can also be performed after peeling a mold.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to a following example.

The production of the side chain crystalline polymer used in the following examples is as follows.
<Synthesis example>
50 parts of behenyl acrylate (manufactured by NOF Corporation), 45 parts of methyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 5 parts of acrylic acid and 0.2 part of perbutyl ND (manufactured by NOF Corporation), each in ethyl acetate In addition to 230 parts, it mixed, and it stirred at 55 degreeC for 4 hours, and polymerized these monomers. The obtained copolymer (side-chain crystalline polymer) had a weight average molecular weight of 600,000 and a melting point of 55 ° C. The weight average molecular weight is a value obtained by measuring a copolymer with GPC and converting the obtained measurement value into polystyrene. Moreover, the said melting | fusing point is the value measured on 10 degree-C / min measurement conditions using DSC.

<Production of imprint mold>
As shown in FIG. 2, the imprint mold concerning this invention was produced. Each member used is as follows.
Surface layer: The side chain crystalline polymer obtained in the synthesis example was used.
Support layer: 625 μm thick silicon was used. The surface of the support layer that supports the surface layer was dry-etched as a surface treatment. The dry etching process was performed with SF ₆ gas.
Master mold: A mold made of silicon having a nanometer-scale fine pattern formed on the surface by EB lithography was used.

  The fine pattern of the master mold has a shape in which a plurality of ridges are arranged in parallel. The ridges have a width of 490 nm and a pitch interval of 180 nm. The width and pitch interval are both average values of n = 10. The fine pattern of the master mold was not subjected to mold release treatment.

The pressurizing conditions are as follows.
Pressure temperature: 70 ° C. (melting point of side chain crystalline polymer + 15 ° C.)
Pressure: 5MPa
Pressurization time: 60 seconds In addition, adjustment of the said pressurization temperature was performed by arrange | positioning a heater in the back surface of a master type | mold, and heating so that the surface temperature of a fine pattern may be set to 70 degreeC with this heater.

  The mold was produced as follows. First, the surface layer was laminated | stacked on the support layer (refer Fig.2 (a)). This lamination was performed by applying a coating solution obtained by adding the side chain crystalline polymer to ethyl acetate on a support layer with a spin coater and drying at an ambient temperature of 100 ° C. The thickness of the laminated surface layer was 1 μm.

  Next, a master mold was placed above the surface layer (see FIG. 2B), and the surface of the surface layer was pressurized with the master mold under the pressure condition (see FIG. 2C). While maintaining the pressurized state by the master mold, the temperature of the surface layer was cooled to room temperature (23 ° C.), which is lower than the melting point of the side chain crystalline polymer, using a fan. And the master type | mold was peeled from the surface of the surface layer, and the mold was obtained (refer FIG.2 (d)).

  The fine pattern of the obtained mold was observed with a scanning electron microscope (magnification: 12,000 times). The result is shown in FIG. As can be seen from the figure, the reverse pattern of the master type fine pattern is accurately transferred onto the surface of the surface layer of the mold. More specifically, it can be seen that a plurality of ridges 30 having a width d1 of 180 nm are arranged in parallel at a pitch interval d2 of 490 nm. The width d1 and the pitch interval d2 are both average values of n = 10.

  Moreover, as a result of visually observing the master-type fine pattern after peeling, the side chain crystalline polymer was not adhered. From these results, it is understood that a fine pattern of a mold can be formed by thermally (nano) imprinting a master type fine pattern on a side chain crystalline polymer. In addition, it can be said that the master-type fine pattern does not need to be subjected to a mold release process and is excellent in productivity. If the obtained mold is used, it is expected that imprint lithography can be performed without performing mold release treatment on the fine pattern of the mold.

Claims (14)

A surface layer having a fine pattern on the surface;
A support layer for supporting a back surface opposite to the front surface of the surface layer,
The surface layer is made of a side chain crystalline polymer,
The imprint mold, wherein the support layer has rigidity. A mold used in imprint lithography that presses and presses a mold against a film on the substrate surface, transfers the fine pattern on the mold surface to the film on the substrate surface, and then cures the film to form a fine pattern on the substrate surface. There,
A surface layer having the fine pattern on the surface;
A support layer for supporting a back surface opposite to the front surface of the surface layer,
The surface layer comprises a side chain crystalline polymer;
The imprint mold, wherein the side-chain crystalline polymer when the mold is pressed against the film on the surface of the substrate is in a crystalline state.   The imprint mold according to claim 1, wherein the side chain crystalline polymer is crystallized at a temperature lower than the melting point and exhibits fluidity at a temperature equal to or higher than the melting point.   The imprint mold according to claim 1, wherein the side chain crystalline polymer has a melting point of 30 ° C. or higher.   The side chain crystalline polymer is 20 to 100 parts by weight of (meth) acrylate having a linear alkyl group having 16 or more carbon atoms, and 0 to 70 parts by weight of (meth) acrylate having an alkyl group having 1 to 6 carbon atoms. The mold for imprinting according to any one of claims 1 to 4, which is a polymer obtained by polymerizing 0 to 10 parts by weight of a polar monomer.   The mold for imprinting according to claim 1, wherein the side chain crystalline polymer has a weight average molecular weight of 100,000 or more.   The mold for imprinting in any one of Claims 1-6 by which the mold release process is not given to the said fine pattern.   The imprint mold according to any one of claims 1 to 7, wherein the fine pattern is on a nano to micrometer scale.   The imprint mold according to any one of claims 1 to 8, wherein a surface treatment is applied to a surface of the support layer that supports the surface layer. Laminating a surface layer composed of a side chain crystalline polymer on a rigid support layer;
Pressing the surface of the surface layer with a master mold having a fine pattern at a temperature equal to or higher than the melting point of the side chain crystalline polymer;
Next, the temperature of the surface layer is set to a temperature lower than the melting point of the side chain crystalline polymer, the master mold is peeled off from the surface of the surface layer, and the fine pattern of the master mold is transferred to the surface of the surface layer;
The manufacturing method of the mold for imprint characterized by including these.   The method for producing an imprint mold according to claim 10, wherein a surface treatment is performed on a surface of the support layer on which the surface layer is laminated.   The method for producing an imprint mold according to claim 10 or 11, wherein a release treatment is not applied to the fine pattern of the master mold. The method for producing an imprint mold according to claim 10, wherein the material constituting the master mold is selected from silicon, silicone, and (SiO ₂ ) glass.   The manufacturing method of the mold for imprints in any one of Claims 10-13 which perform the said pressurization at the temperature of melting | fusing point +10 degreeC-melting | fusing point +30 degreeC of the said side chain crystalline polymer.