JP4497014B2 - Method for manufacturing polarization separating element - Google Patents

Description

  The present invention relates to a method for forming a fine pattern and a method for manufacturing a polarization separation element using the method for forming a fine pattern.

  A technique for forming a film on the surface of the workpiece at room temperature, then embossing with a mold, forming a pattern made of the film on the surface of the workpiece, and processing the workpiece using this as a resist is nanoimprint lithography. Known in the art.

  However, until now, thermoplastic polymers such as PMMA have been used as resist forming materials. For this reason, heating is required at the time of die pressing, and there has been a problem that the position accuracy or line width accuracy of the transferred pattern after the die pressing is lowered due to a temperature change during cooling after the die pressing. In addition, since the process is a heating-cooling process, there are problems that workability is lowered and the accuracy of the transfer pattern is lowered due to the resist adhering to the mold material in the transfer process.

To solve the above problems, _{[R n Si (OH) 4-} n ] (where, R represents an alkyl radical, n is an integer of 0 to 3) as a main component a mixture of siloxane component and a solvent represented by the solution A method of obtaining a high-precision pattern by performing nano-implementing lithography using SOG (spin on glass) is disclosed (Patent Document 1).
Japanese Patent Laid-Open No. 2003-100609

  However, in the conventional technology, the adhesion of SOG to the mold material may be confirmed, and the conventional problems have not been completely solved.

  Therefore, an object of the present invention is to apply a liquid material excellent in releasability with a mold material to an imprinting lithography method, thereby forming a fine pattern, and a method for forming the fine pattern. An object of the present invention is to provide a method for manufacturing a polarization separation element using the above.

  As a result of diligent study, the present inventors have found that a reed-type polysilsesquioxane having a specific functional group has a good reproducibility of pattern transfer characteristics in a plurality of transfer processes and can withstand multiple uses. The knowledge that it can be used as is obtained.

  The present invention has been made on the basis of such knowledge, and a step of forming a liquid material film by applying a liquid material containing a saddle type polysilsesquioxane represented by the following general formula (1) to the surface of a work material; A step of temporarily curing the liquid material film to form a temporary cured film, a step of transferring the pattern of the mold material to the temporary cured film by a mold material on which a fine pattern is formed, and a complete curing of the surface of the work material And a step of forming a fine pattern.

（式中、Ｒ¹〜Ｒ⁹すべて同時に又はそれぞれ独立に、メタクリル基、エポキシ基、メチル基、フルオロアルキル基、ＣＦ₃（ＣＦ₂）ｎ−Ｒ¹⁰を意味する。ここで、Ｒ¹⁰は炭素数１ないし１２個の非置換または置換二価炭化水素基を意味し、ｎは０〜１０の整数を意味する。）

(Wherein R ^{1 to} R ⁹ all simultaneously or independently represent a methacryl group, an epoxy group, a methyl group, a fluoroalkyl group, or CF ₃ (CF ₂ ) n—R ¹⁰ , where R ¹⁰ is carbon. (It means several 1 to 12 unsubstituted or substituted divalent hydrocarbon groups, and n means an integer of 0 to 10.)

  The present invention also includes a step of forming a metal thin film on a substrate, and a liquid material containing a saddle-type polysilsesquioxane represented by the general formula (1) is applied to the surface of the metal thin film to form a liquid material film. A step of forming, a step of temporarily curing the liquid material film to form a temporary cured film, a step of transferring a pattern of the mold material to the temporary cured film by a mold material on which a fine pattern is formed, and the material to be processed The present invention provides a method for manufacturing a polarization separation element, comprising: a step of completely curing a surface; and a step of etching the metal thin film.

  As described above, the present invention includes a step of applying a liquid material containing a polysilsesquioxane having a cage structure represented by the following general formula (1) to the surface of a work material to form a liquid material film, and the liquid material A step of temporarily curing the film to form a temporary cured film, a step of transferring the pattern of the mold material to the temporary cured film with a mold material on which a fine pattern is formed, a step of completely curing the surface of the work material, Is a fine pattern forming method.

（式中、Ｒ¹〜Ｒ⁹すべて同時に又はそれぞれ独立に、メタクリル基、エポキシ基、メチル基、フルオロアルキル基、ＣＦ₃（ＣＦ₂）ｎ−Ｒ¹⁰を意味する。ここで、Ｒ¹⁰は炭素数１ないし１２個の非置換または置換二価炭化水素基を意味し、ｎは０〜１０の整数を意味する。）

(Wherein R ^{1 to} R ⁹ all simultaneously or independently represent a methacryl group, an epoxy group, a methyl group, a fluoroalkyl group, or CF ₃ (CF ₂ ) n—R ¹⁰ , where R ¹⁰ is carbon. (It means several 1 to 12 unsubstituted or substituted divalent hydrocarbon groups, and n means an integer of 0 to 10.)

[Synthesis of vertical polysilsesquioxane]
Examples of the alkoxysilane used for the synthesis of the cage polysilsesquioxane represented by the general formula (1) include 3-glycidoxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyl. Examples include trimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, and the like.

  Here, the specific characteristic of the cage type | mold polysilsesquioxane obtained can be improved by selecting an alkoxysilane suitably. Specifically, when 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, or 3-methacryloxypropyltrimethoxysilane is used, a cage-type polysilsesquioxy is used. The polymerizability of sun is improved, thereby improving the film formability of the liquid material.

  In addition, when 3,3,3-trifluoropropyltrimethoxysilane is used, the releasability of the cage polysilsesquioxane is improved. These are summarized in Table 1.

  Next, a plurality of types of alkoxysilanes as described above, water and alcohols such as methanol, ethanol and isopropyl alcohol as necessary, ethers such as diethyl ether and tetrahydrofuran (THF), acetone, methyl isobutyl ketone, etc. A dilute solvent typified by hydrocarbons such as ketones and toluene is mixed at a predetermined ratio to obtain a mixed solution.

  Next, a hydrolysis and polycondensation catalyst such as an acid catalyst and a base catalyst is added to the obtained mixed solution while stirring. These catalysts may be added in advance to the solvent or water used for the reaction.

  Examples of the acid catalyst (including a solid acid catalyst) include inorganic acids such as sulfuric acid, nitric acid, phosphoric acid, and organic sulfonic acids (for example, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, methanesulfonic acid, ethane). Organic acids such as sulfonic acid, etc., and examples of the base catalyst include inorganic bases such as ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, tertiary amines (trimethylamine, triethylamine, tributylamine) , Triethanolamine, pyridine and the like), organic bases such as tetramethylammonium hydroxide, choline and the like. Of these, sodium hydroxide, potassium hydroxide, and tetraalkylammonium hydroxide, which have a high activity as a base and are easily removed during post-treatment, are preferred.

  After adding the hydrolysis catalyst, the alkoxysilane is polycondensed by heating at a predetermined temperature while stirring. The predetermined temperature (reaction temperature) is preferably 5 to 140 ° C, and more preferably 30 to 60 ° C. If the reaction temperature is too high, the reaction of the curing reactive group may occur. Conversely, if the reaction temperature is too low, the progress of the reaction is remarkably slowed. The reaction time is preferably 1 to 48 hours, and more preferably 3 to 18 hours. If the reaction time is too long, the reaction of the curing reactive group may occur. Conversely, if the reaction time is too short, the reaction is not completed. If necessary, treatments such as neutralization, removal of diluted solvent, and drying are performed.

  By using the method as described above, a polysilsesquioxane (polysiloxane material) having a cage structure represented by the general formula (1) can be obtained. The cage polysilsesquioxane represented by the general formula (1) exhibits various functions according to the alkoxysilane described above.

Specifically, when R ^{1 to} R ^{9 in} the general formula (1) are polymerizable groups such as a methacryl group, an epoxy group, and a methyl group, the film formability of the liquid material is improved. In the general formula (1), R ^{1 to} R ⁹ are fluoroalkyl groups, CF ₃ (CF ₂ ) n—R ¹⁰ (R ¹⁰ is an unsubstituted or substituted divalent hydrocarbon group having 1 to 12 carbon atoms, and n is In the case of a releasable group such as 0 to 10), the releasability of the liquid material is improved. These are summarized in Table 2.

When using a cage polysilsesquioxane represented by Formula (1), the functional groups of R ¹ to R ⁹ in the formula may be used to more mixing one kind of thing, the R ¹ to R ⁹ Two or more types of functional groups may be used alone. Further, two or more functional groups of R ^{1 to} R ⁹ may be used in combination.

[Preparation of liquid material]
Next, a liquid material containing the polysiloxane material obtained in the above step is prepared. The polysiloxane material obtained in the above step may be used as a liquid material as it is, or a solvent such as diethylene glycol ethyl ether acetate may be added as necessary.

  Moreover, you may add a hardening | curing agent (polymerization initiator) to a liquid material as needed. Thereby, hardening of a coating film which is mentioned later can be performed easily. Examples of such a curing agent include light such as benzophenone, 1-hydroxycyclohexyl phenyl ketone, (thiophenoxyphenyl) diphenylsulfonium hexafluorophosphate, bis (diphenylsulfonium) diphenylthioether hexafluorophosphate, and the like. Examples of the polymerization initiator include thermal polymerization initiators such as azobisisobutyronitrile and azobismethylbutyronitrile, and one or more of these can be used in combination.

  Moreover, you may perform a filtration process with respect to a liquid material as needed. Thereby, impurities contained in the liquid material can be removed, and an alignment film having a uniform thickness can be efficiently formed.

[Method for Manufacturing Separated Polarizing Element]
In the present embodiment, an example will be described in which a fine pattern of wire grid type aluminum having a pitch of 100 to 140 nm is formed on the surface of a glass substrate. As a method for forming a fine pattern, a conventionally known imprint lithography method can be applied except that a liquid material containing a cage polysilsesquioxane represented by the general formula (1) is used as the liquid material. In particular, in this embodiment, since the liquid material containing the cage polysilsesquioxane represented by the general formula (1) is used, it can be applied to nanoimprint lithography that forms a nano-order fine pattern.

  An aluminum thin film is formed on the glass substrate by sputtering or the like. This glass substrate is set on a spin coater, and the above-mentioned liquid material is applied to the surface of the aluminum thin film. Then, first, spin coating is performed under conditions of 600 to 800 rpm and 4 to 6 seconds, and subsequently spin coating is performed under conditions of 1000 to 1400 rpm and 15 to 25 seconds. Thus, a liquid material film is formed on the surface of the aluminum thin film.

  This glass substrate is dried for 3 to 5 minutes with a heat source such as a hot plate heated to 100 to 200 ° C. After drying, the surface of the glass substrate is irradiated with light with a light source such as a metal hydrate lamp for 3 to 10 minutes to temporarily cure the liquid material film.

Next, using a mold having a predetermined fine pattern formed on the surface, the temporarily cured film is pressed at a pressure of ²⁰ to 30 kgf / cm ² for 5 to 15 minutes.

After removing the mold, heating was performed at 150 to 250 ° C. for 2 to 4 hours in an air atmosphere and normal pressure to completely cure the film, whereby a fine pattern of SiO ₂ having a pitch of 100 to 140 nm was formed. A glass substrate is obtained.

  Then, a wire grid type polarizing plate having a pitch of 100 to 140 nm can be obtained by etching the aluminum thin film by a dry etching method or the like.

  In the present embodiment, an example in which a polarizing plate is manufactured as a separation polarizing element has been shown. However, the present invention is not limited to this. For example, the present invention can be applied to manufacturing a diffraction optical element, an antireflection film (moth eye), and the like. it can.

(1) Synthesis of vertical silsesquioxane A mixture of 1N sodium hydroxide aqueous solution 22.5 g (containing 1.2 mol as water), tetrahydrofuran 600 ml and alkoxysilane shown in Table 1 in a 1 L three-necked flask equipped with a thread 120 mmol was added, and the mixture was stirred at 60 ° C. for 3 hours, and then allowed to cool. To the solution was added 22.5 ml of a 1N hydrochloric acid aqueous solution, and tetrahydrofuran was distilled off. And 50 ml of toluene was added, the solvent phase and the water phase were isolate | separated, the solvent phase was fractionated, and the water phase was discarded. The separated solvent phase was washed with distilled water and a saturated aqueous solution of sodium chloride, and dehydrated with anhydrous magnesium sulfate to obtain a cage polysilsesquioxane.

  At this time, eight types of caged polysilsesquioxanes were prepared by appropriately changing the combinations of alkoxysilanes shown in Table 1.

(2) Preparation of coating liquid 2.00 parts of diethylene glycol ethyl ether acetate was mixed with 1.00 parts of the 1-8 vertical polysilsesquioxane obtained in (1). The mixed solution was filtered using a filter having a pore size of 0.2 μm. 0.01 parts of photopolymerizer A or B was added to the obtained filtrate to obtain a desired coating solution.

  In addition, about 1-5, as a photoinitiator A, a 50% propylene carbonate solution of a mixture of (thiophenoxyphenyl) diphenylsulfonium hexafluorophosphate and bis (diphenylsulfonium) diphenylthioether hexafluorophosphate ( Gelest, code OMPH076) was added. On the other hand, about 6-8, benzophenone (made by Tokyo Chemical Industry Co., Ltd.) was added as the photoinitiator B.

(3) Nanoimprinting lithography An aluminum substrate was set on a spin coater, and the above coating solution was applied to the surface of the aluminum substrate. First, spin coating was performed under conditions of 700 rpm and 5 seconds, and subsequently, spin coating was performed under conditions of 1200 rpm and 20 seconds. As a result, a coating liquid film was formed on the surface of the aluminum substrate. This aluminum substrate was dried on a hot plate heated to 150 ° C. for 3 to 5 minutes. After drying, the surface of the aluminum substrate was irradiated with light for 5 minutes with a metal hydrate lamp to temporarily cure the film. Next, using a SiO ₂ / Si mold having a predetermined fine pattern formed on the surface, the temporarily cured film was pressed at a pressure of 25 kgf / cm ² for 10 minutes. After removing the mold, heating was performed at 200 ° C. for 3 hours in an air atmosphere and normal pressure to completely cure the film to obtain an aluminum substrate on which a desired pattern was formed. And the aluminum thin film was etched by the dry etching method, and the wire grid type polarizing plate which has a pitch of 100 nm was obtained.

  Since the liquid material used in the method for forming a fine pattern according to the present invention is excellent in releasability, the liquid material does not adhere to the mold material, and as a result, a fine pattern with few defects can be obtained. In addition, since there is little dimensional shrinkage accompanying curing, a highly accurate pattern with high positional accuracy and line width accuracy of the transferred pattern after embossing can be obtained.

  Furthermore, by changing the functional group of the cage polysilsesquioxane represented by the general formula (1), various functions can be imparted, and as a result, the application range can be expanded.

Claims (2)

Forming a metal thin film on the substrate;
Applying a liquid material containing cage polysilsesquioxane represented by the following general formula (1) to the surface of the metal thin film to form a liquid material film;
Preliminarily curing the liquid material film to form a temporary cured film;
A step of transferring a pattern of the mold material to the temporarily cured film by a mold material on which a fine pattern is formed;
Fully curing the surface of the work material;
Etching the metal thin film;
A method of manufacturing a polarization separation element comprising:

(Wherein R1 to R9 all simultaneously or independently represent a methacryl group, an epoxy group, a methyl group, a fluoroalkyl group, or CF3 (CF2) n-R10. Here, R10 has 1 to 12 carbon atoms. (It means an unsubstituted or substituted divalent hydrocarbon group, and n means an integer of 0 to 10.) The main components of the cage polysilsesquioxane are 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3 , 3,3 is trifluoropropyl one or more members selected from the group consisting of trimethoxysilane, the method of manufacturing the polarization separating element according to claim 1, wherein.