JP2012049177A - Fine pattern forming method and exposure apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine pattern forming method and an exposure apparatus, in which reoxidation of a thermally reactive resist after exposure can be suppressed to suppress reduction in development difference, and thus a fine pattern can be accurately formed.SOLUTION: The fine pattern forming method of the present invention forms a pattern on a resist layer provided on a substrate and containing a thermally reactive resist material which reductively reacts by being heated. The fine pattern forming method comprises: a reduction step including a heating period in which a predetermined area of the resist layer is reduced by heating, and a cooling period in which the predetermined area of the resist layer is cooled under an inert atmosphere or a reductive atmosphere; and a development step of developing the resist layer.

Description

  The present invention relates to a fine pattern forming method, an exposure apparatus, and a nanoimprint mold that enable precise exposure by laser to an imprint original plate comprising at least a resist layer and a substrate.

  In recent years, with increasing demands for higher density and higher integration in the fields of semiconductors, optical / magnetic recording, etc., a fine pattern processing technique of several hundred nm to several tens of nm or less is essential. Therefore, in order to realize such fine pattern processing, elemental technologies of each process such as a mask / stepper, exposure, resist material and the like are actively studied.

  For example, in the mask / stepper process, a special mask called a phase shift mask is used to provide a phase difference to the light and improve the precision of fine pattern processing by the effect of interference, or between the stepper lens and the wafer. An immersion technique that enables fine pattern processing by filling a liquid and largely refracting light that has passed through a lens has been studied. However, it is very difficult to reduce the manufacturing cost because the former requires an enormous cost for mask development and the latter requires an expensive apparatus.

  On the other hand, many studies have been made on resist materials. Currently, the most common resist material is a photoreactive organic resist (hereinafter also referred to as a photoresist) that reacts with an exposure light source such as ultraviolet light, electron beam, and X-ray (for example, Patent Document 1, Non-Patent Document). Reference 1).

In the laser light used for exposure, the intensity of the laser light normally focused by a lens shows a Gaussian distribution shape. At this time, the spot diameter is defined as 1 / e ² . Generally, the reaction of a photoresist is initiated by absorbing energy represented by E = hν (E: energy, h: Planck constant, ν: wavelength). Therefore, the reaction does not strongly depend on the intensity of light, but rather depends on the wavelength of light, so that almost all reaction occurs in the irradiated portion (exposure mark). Therefore, when a photoresist is used, exposure is performed faithfully with respect to the spot diameter.

  Although a method using a photoreactive organic resist is a very effective method for forming a fine pattern of about several hundreds of nanometers, a finer pattern is formed because a photoreactive photoresist is used. Therefore, it is necessary to perform exposure with a spot smaller than the pattern required in principle. For this reason, KrF, ArF laser, etc. with a short wavelength must be used as an exposure light source. However, since these light source devices are very large and expensive, they are not suitable from the viewpoint of manufacturing cost reduction.

  On the other hand, when an object is irradiated with laser light having a Gaussian distribution, the temperature of the object also exhibits the same Gaussian distribution as the intensity distribution of the laser light. At this time, when a resist that reacts at a certain temperature or more, that is, a heat-reactive resist, is used, the reaction proceeds only at a portion that exceeds a predetermined temperature, and therefore, it is possible to expose a range smaller than the spot diameter. That is, a pattern finer than the spot diameter can be formed without reducing the wavelength of the exposure light source. Therefore, the influence of the exposure light source wavelength can be reduced by using the heat-reactive resist.

Such heat-reactive resists can be classified into the following types as reactions by exposure.
(1) A type in which the resist in the irradiated area sublimates and explodes by exposure to laser light irradiation to form grooves and holes. (2) Oxidation of the resist in the irradiated area proceeds by irradiation with laser light by exposure. Grooves and holes are formed using the difference in solubility in water and alkali. (3) The reduction of the resist in the irradiated area is advanced by laser light irradiation by exposure, and the difference in solubility in acid and alkali due to the difference in the degree of oxidation. Type that uses grooves to form grooves and holes

  As one of the methods for exposing the resist of type (1), a method of irradiating laser light while moving an inert gas on the resist layer on the resist layer has been proposed (see Patent Document 2). By blowing an inert gas, the foreign substance consisting of the resist layer blown off by the laser beam can be removed, and at the same time, alteration of the surrounding resist material removed by laser heating can be prevented.

JP 2007-144959 A JP 2009-276632 A

Published by Information Technology Corporation “Latest Resist Materials” 59-P. 76

  By the way, in the type (3) resist in which the metal oxide is heated to change the oxidation degree by a reduction reaction, there is a material in which a decomposition reaction occurs very steeply at a predetermined temperature. In such a material, only the portion that has been heated to a predetermined temperature or more when heated by laser light irradiation is rapidly reduced, and the portion that has not reached the predetermined temperature does not undergo a reduction reaction at all. Thus, it is possible to increase the difference in development, and it is considered possible to accurately control the width and length of the grooves and holes.

  However, in the process of cooling the heat-reactive resist after laser irradiation, the reoxidation of the reduced portion that has been exposed to laser irradiation above the predetermined temperature proceeds, and the development difference due to acid or alkali becomes small. There is a problem in that the shape of the groove or hole cannot be obtained or is disturbed.

  The present invention has been made in view of the above points, and can provide a fine pattern forming method capable of suppressing reoxidation of a heat-reactive resist after exposure and accurately forming a fine pattern while suppressing a reduction in development difference. An object is to provide an exposure apparatus.

  As a result of intensive studies and repeated experiments in order to solve such problems, the present inventors have set the oxygen concentration in the vicinity of the heat-reactive resist material heated by laser irradiation to a certain value or less, or the concentration of the reducing gas. It has been found that the oxidation degree of the heat-reactive resist (metal oxide) reduced by being heated to a predetermined temperature or higher can be maintained even after cooling by setting it above a certain value. The invention has been completed. Specifically, the present invention is as follows.

  The fine pattern forming method of the present invention is a fine pattern forming method for forming a pattern on a resist layer that is provided on a substrate and includes a heat-reactive resist material that undergoes a reduction reaction by heating. A reduction process comprising: a heating period for heating and reducing the area; and a cooling period for cooling the predetermined area of the resist layer in an inert atmosphere or a reducing atmosphere; and a development process for developing the resist layer It is characterized by comprising.

  In the fine pattern forming method of the present invention, it is preferable that an oxygen concentration in the vicinity of the resist layer as the inert atmosphere is in a range of 0 vol% to 5 vol% in the cooling period.

  In the fine pattern forming method of the present invention, it is preferable that the inert gas concentration in the vicinity of the resist layer as the inert atmosphere is in the range of 95 vol% to 100 vol% in the cooling period.

  In the fine pattern forming method of the present invention, the inert gas is preferably at least one selected from the group consisting of nitrogen, carbon dioxide, helium, argon, krypton, xenon, radon, and fluorocarbon.

  In the fine pattern forming method of the present invention, it is preferable that the reducing gas concentration in the vicinity of the resist layer as the reducing atmosphere is in the range of 10 vol% to 100 vol% in the cooling period.

  In the fine pattern forming method of the present invention, the reducing gas concentration in the vicinity of the resist layer as the reducing atmosphere is in the range of 10 vol% to 100 vol% and the oxygen concentration is 0 vol% to 8 vol% in the cooling period. It is preferable to be in the range.

  In the fine pattern forming method of the present invention, the reducing gas is hydrogen, carbon monoxide, sulfur dioxide, ammonia, formaldehyde, a saturated hydrocarbon gas having 1 to 5 carbon atoms, and 1 to 5 carbon atoms. It is preferable that it is at least one selected from the group consisting of the following unsaturated hydrocarbon gases.

  In the fine pattern forming method of the present invention, the thermal reaction type resist material is preferably an inorganic resist material.

  In the fine pattern forming method of the present invention, it is preferable that the substrate has a roll shape or a flat plate shape.

  The exposure apparatus of the present invention is an exposure apparatus that forms a fine pattern on a work material having a base material and a resist layer that is provided on the base material and includes a heat-reactive resist material that undergoes a reduction reaction by heating. An exposure chamber that accommodates the processing material, an irradiation unit that irradiates a predetermined region of the resist layer of the processing material in the exposure chamber with laser light, and an exhaust that exhausts oxygen in the exposure chamber And a control unit for controlling the oxygen concentration in the exposure chamber by the exhaust means, and after irradiating a predetermined region of the resist layer of the processing material with a laser beam, a predetermined cooling period, The exposure chamber is decompressed so that the oxygen concentration is in the range of 0 vol% to 5 vol%.

  The exposure apparatus of the present invention is an exposure apparatus that forms a fine pattern on a work material having a base material and a resist layer that is provided on the base material and includes a heat-reactive resist material that undergoes a reduction reaction by heating. An exposure chamber that accommodates the processing material, an irradiation unit that irradiates a predetermined region of the resist layer of the processing material in the exposure chamber with laser light, and an exhaust that exhausts oxygen in the exposure chamber Means, a gas supply part for supplying an inert gas or a reducing gas into the exposure chamber, and a control part for controlling the oxygen concentration in the exposure chamber by the exhaust means and the gas supply part. A predetermined region of the resist layer of the material is irradiated with laser light, and then the exposure chamber is made an inert atmosphere or a reducing atmosphere for a predetermined cooling period.

  In the exposure apparatus of the present invention, it is preferable to reduce the oxygen concentration in the exposure chamber using an oxygen adsorbent.

  The mold for nanoimprinting of the present invention is obtained by using the fine pattern forming method.

  According to the present invention, it is possible to provide a fine pattern forming method and an exposure apparatus that can suppress reoxidation of a heat-reactive resist after exposure and can accurately form a fine pattern by suppressing a decrease in development difference.

It is a figure which shows an example of the exposure apparatus which concerns on embodiment of this invention. It is a figure which shows another example of the exposure apparatus which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In the fine pattern formation method according to the present embodiment, a pattern is formed on a resist layer that is provided on a substrate and includes a heat-reactive resist material that undergoes a reduction reaction by heating. This fine pattern forming method includes a reduction process in which a heat-reactive resist material in a predetermined region of a resist layer is subjected to a reduction reaction by heating to reduce the degree of oxidation, and a development process to develop the resist layer that has undergone the reduction process. . The reduction step includes a heating period t1 in which a predetermined region of the resist layer is heated to perform a reduction reaction, and a cooling period t2 in which the predetermined region of the reduced resist layer is cooled in an inert atmosphere or a reducing atmosphere. Including.

  In the fine pattern forming method according to the present embodiment, the reduced resist layer is reoxidized by cooling the resist layer reduced by heating in an inert atmosphere or a reducing atmosphere in the reduction step. Is suppressed. Therefore, it is possible to suppress a decrease in development difference in the development process due to the difference in the degree of oxidation between the heat-reactive resist material reduced by heating and the unreacted heat-reactive resist material. A pattern can be formed accurately.

  Hereinafter, an embodiment of an exposure apparatus and a fine pattern forming method used in the fine pattern forming method will be described in detail. In the following embodiments, an example in which the fine pattern forming method according to the present invention is applied to an exposure apparatus will be described. However, the fine pattern forming method according to the present invention is applied to at least a predetermined region of a resist layer by heating. The present invention is not limited to the exposure apparatus as long as it can reduce the heat-reactive resist material, and can be applied to various apparatuses.

FIG. 1 is a diagram showing an example of an exposure apparatus according to an embodiment of the present invention.
As shown in FIG. 1, an exposure apparatus 1 according to the present embodiment includes a chamber 11 (exposure chamber) having a space inside, and a laser beam applied to a flat substrate 12 as a workpiece to be processed. And a laser pickup unit 13 (laser light irradiation unit). The flat plate substrate 12 includes a substrate (not shown) and a resist layer (not shown) provided on the substrate and including a heat-reactive resist material. The laser pickup unit 13 is provided on the resist layer. Is irradiated with laser light. The flat plate base 12 is connected to the spindle motor 14 by vacuum suction or the like, so that the rotational speed and linear velocity of the flat plate base 12 at the time of exposure can be accurately controlled.

  The laser pickup unit 13 monitors the reflected light and irradiates a predetermined region of the resist layer (not shown) of the flat plate base material 12 with autofocus to irradiate the laser beam, and the resist layer (not shown) of the flat plate base material 12. A predetermined area is exposed. The laser pickup unit 13 is mounted on the single-axis control stage 15. The uniaxial control stage 15 has a function of reciprocating the laser pickup unit 13 on a straight line passing through the center of rotation of the flat plate base material 12.

  A gas supply source 17 for supplying an inert gas or a reducing gas is connected to the chamber 11 via a valve 16 so that the inert gas or the reducing gas can be supplied into the chamber 11. Further, a vacuum pump 19 for discharging oxygen in the chamber 11 is connected to the chamber 11 via a valve 18, and the oxygen in the chamber 11 can be discharged by the vacuum pump 19.

  Further, the exposure apparatus 1 includes a control unit 20 that controls various gas concentrations in the chamber 11 and the degree of pressure reduction. The control unit 20 is connected to the valve 16 and the gas supply source 17, and controls the valve opening degree of the valve 16 and the type and supply amount of the inert gas or reducing gas supplied from the gas supply source 17. The control unit 20 is connected to the valve 18 and the vacuum pump 19, respectively, and controls the valve opening degree of the valve 18 and the amount of oxygen discharged from the chamber 11 by the vacuum pump 19.

  As described above, in the exposure apparatus 1, at least a position where the laser beam is irradiated onto the flat substrate 12 is covered with the chamber 11. The oxygen concentration in the chamber 11 (hereinafter also referred to as exposure chamber) can be adjusted by the controller 20 by appropriately operating the valve 16, the valve 18, and the vacuum pump 19. In the exposure apparatus 1, the control unit 20 controls the valve 16, the gas supply source 17, the valve 18, and the vacuum pump 19 to reduce oxygen around the resist layer of the flat plate substrate 12 in the chamber 11. Alternatively, exposure is performed in a state where an inert gas is set to a predetermined concentration (inert atmosphere) or a state where the reducing gas is set to a predetermined concentration (reducing atmosphere).

  As an example of control of the oxygen concentration in the chamber 11, the valve 16 is closed, the valve 18 is opened, the gas (oxygen) in the chamber 11 is discharged by the vacuum pump 19, and the pressure in the chamber 11 is reduced. it can. The oxygen concentration can also be adjusted by evacuating the chamber 11 with the vacuum pump 19 and then opening the valve 16 and filling with an inert gas such as nitrogen from the gas supply source 17. Alternatively, the oxygen concentration may be adjusted by opening the valve 16 and exhausting with the vacuum pump 19 while flowing an inert gas such as nitrogen. Further, the oxygen concentration in the chamber 11 can be adjusted by removing the vacuum pump 19, opening the valve 16, allowing an inert gas to flow in, opening the valve 18, and discharging oxygen in the chamber 11 out of the chamber 11. it can. In this case, since no pressure is applied to the chamber 11, a very simple structure can be obtained, which is preferable from the viewpoint of miniaturization of the apparatus.

FIG. 2 shows an exposure apparatus 2 according to another example of the embodiment of the present invention.
As shown in FIG. 2, the exposure apparatus 2 includes a chamber 21 having a space inside, and a laser pickup unit 23 that is disposed in the chamber 21 and irradiates a sleeve base material 22 as a workpiece to be irradiated with laser light. . The sleeve base material 22 has a cylindrical base material (not shown) and a resist layer (not shown) provided on the outer peripheral surface of the base material and containing a heat-reactive resist material. Laser light is emitted from the laser pickup unit 23. The sleeve base material 22 is connected to the spindle motor 24 by a method such as three-claw chucking. Thereby, the rotation speed and linear velocity of the sleeve base material 22 at the time of exposure can be accurately controlled and rotated. The laser pickup unit 23 monitors the reflected light and auto-focuses the resist layer (not shown) of the sleeve base material 22 to irradiate the laser beam, thereby exposing the resist layer (not shown) of the sleeve base material 22. The laser pickup unit 23 is mounted on the uniaxial control stage 25. The uniaxial control stage 25 has a function of reciprocating the laser pickup unit 23 on a straight line passing through the rotation center of the sleeve base material 22.

  A gas supply source 27 for supplying an inert gas or a reducing gas is connected to the chamber 21 via a valve 26 so that the inert gas or the reducing gas can be supplied into the chamber 21. Further, a vacuum pump 29 for discharging oxygen in the chamber 21 is connected to the chamber 21 through a valve 28, and the oxygen in the chamber 21 can be discharged by the vacuum pump 29.

  Further, the exposure apparatus 2 includes a control unit 30 that controls various gas concentrations in the chamber 21 and the degree of pressure reduction. The control unit 30 is connected to the valve 26 and the gas supply source 27, and controls the valve opening degree of the valve 26 and the type and supply amount of the inert gas or reducing gas supplied from the gas supply source 27. The control unit 30 is connected to the valve 28 and the vacuum pump 29, respectively, and controls the valve opening degree of the valve 28 and the amount of oxygen discharged from the chamber 21 by the vacuum pump 29.

  Thus, in the exposure apparatus 2, at least a position where the laser beam is irradiated onto the sleeve base material 22 is covered with the chamber 21. The oxygen concentration in the chamber 21 (hereinafter also referred to as exposure chamber) can be adjusted by the controller 30 by appropriately operating the valve 26, the gas supply source 27, the valve 28, and the vacuum pump 29. In the exposure apparatus 2, the control unit 20 controls the valve 26, the gas supply source 27, the valve 28, and the vacuum pump 29 to reduce oxygen around the resist layer of the sleeve base material 22 in the chamber 21. Alternatively, exposure is performed in a state where an inert gas is set to a predetermined concentration (inert atmosphere) or a state where the reducing gas is set to a predetermined concentration (reducing atmosphere).

  As an example of adjusting the oxygen concentration in the chamber 21, the valve 26 is closed, the valve 28 is opened, the gas (oxygen) in the chamber 21 is exhausted by the vacuum pump 29, and the pressure in the chamber 21 is reduced. it can. The oxygen concentration can also be adjusted by once evacuating the chamber 21 and then opening the valve 26 and filling with an inert gas such as nitrogen. Also, the oxygen concentration in the chamber 21 can be adjusted by removing the vacuum pump 29, opening the valve 26, allowing an inert gas to flow in, opening the valve 28, and discharging the oxygen in the chamber 21 out of the chamber 21. it can. In this case, since no pressure is applied to the chamber 21, a very simple structure can be obtained, which is preferable from the viewpoint of downsizing the apparatus.

  In the present invention, the inert gas used for reducing the oxygen concentration in the chambers 11 and 21 (exposure chamber) is not particularly limited as long as it is an inert gas having no chemical reactivity, and examples thereof include helium and neon. And rare gases such as argon, krypton, xenon and radon, inorganic gases such as nitrogen and carbon dioxide, and fluorocarbons. These gases may be used alone or in combination of two or more. Among these inert gases, at least one inert gas selected from the group consisting of nitrogen, carbon dioxide, helium, argon, krypton, xenon, radon, and fluorocarbon is preferable, and the price, safety, and availability are improved. In consideration, at least one inert gas selected from the group consisting of argon, nitrogen, and carbon dioxide is more preferable. The concentration range of the inert gas may be 95 vol% or more and 100 vol% or less, preferably 99 vol% or more and 100 vol% or less, and more preferably 99.5 vol% or more and 100 vol% or less. As the concentration of the inert gas increases, the oxygen concentration decreases, thereby increasing the reoxidation suppressing effect.

  In the exposure apparatuses 1 and 2 according to the present embodiment, the flat substrate 12 and the sleeve substrate 22 are covered with the chambers 11 and 21, so that the oxygen adsorbent is used to reduce the oxygen concentration. , 21 (the exposure chamber) may be reduced in oxygen concentration. As an oxygen adsorbent, a metal such as an alkali metal, alkaline earth metal, aluminum, titanium, or iron may be adsorbed as an oxygen adsorbent (oxygen getter) at room temperature or by heating, or a compound having an aldehyde group, An organic compound such as a chain hydrocarbon polymer having an unsaturated group may also be used. Examples of the compound having an aldehyde group include formaldehyde, acetaldehyde, propionaldehyde, butanal, pentanal, hexanal and the like. Further, saccharides such as allose, talose, growth, glucose, altrose, mannose, galactose, idose, ribose, lyxose, arabinose, apiose may be used. As the chain hydrocarbon polymer having an unsaturated group, liquid butadiene oligomer, liquid isoprene oligomer, squalene, liquid acetylene oligomer, liquid pentadiene oligomer, liquid oligoester acrylate, liquid butene oligomer, liquid styrene butadiene rubber, liquid nitrile rubber And polymers having various molecular weights such as liquid chloroprene oligomers.

  The oxygen concentration range around the resist layer of exposure apparatuses 1 and 2 according to the present embodiment may be 0 vol% or more and 5 vol% or less, preferably 0 vol% or more and 1 vol% or less, and 0 vol% or more and 0.5 vol% or less. More preferably, it is 0 vol% or more and 0.1 vol% or less, Most preferably, it is 0 vol% or more and 0.01 vol% or less. When the oxygen concentration exceeds 5 vol%, the probability of contact of oxygen with the resist material is increased and reoxidation is likely to occur, and the reoxidation suppressing effect is low. On the other hand, when the oxygen concentration is lowered, the probability of contact of oxygen with the resist material is lowered and reoxidation is further suppressed. However, in order to significantly reduce the oxygen concentration, an increase in cost is unavoidable in terms of equipment, so the oxygen concentration in the above range is a preferable range.

  In the present invention, exposure may be performed in a reducing atmosphere in which the reducing gas around the resist layer has a predetermined concentration. In the exposure apparatus 1 shown in FIG. 1, the vacuum pump 19 is removed, the valve 16 is opened, a reducing gas is introduced, the valve 18 is opened, and oxygen in the chamber 11 is exhausted out of the chamber 11. The concentration of the reducing gas in the (exposure chamber) can be adjusted. In the exposure apparatus 2 shown in FIG. 2, the concentration of the reducing gas can be adjusted similarly.

  Examples of the reducing gas that can be used in the present invention include inorganic gases such as hydrogen, carbon monoxide, sulfur dioxide, and ammonia, or formaldehyde, saturated hydrocarbon gas having 1 to 5 carbon atoms, and 1 to carbon atoms. 5 unsaturated hydrocarbon gas, city gas, etc., and examples thereof include methane, ethane, ethylene, acetylene, propane, propylene, butane, butene, pentane, and pentyne. Of course, these gases may be used alone or in combination of two or more. Among these reducing gases, saturated hydrocarbon gas having 1 to 5 carbon atoms such as hydrogen, carbon monoxide, sulfur dioxide, ammonia, formaldehyde, methane, ethane, propane, and butane, and 1 to 5 carbon atoms. At least one reducing gas selected from the group consisting of unsaturated hydrocarbon gases is preferred, and in view of price, safety, and availability, hydrogen, carbon monoxide, sulfur dioxide, methane, ethane, propane, and butane At least one reducing gas selected from the group consisting of is preferable. Of these, carbon monoxide and methane are more preferable.

  The concentration range of the reducing gas that can be used in the present invention may be 10 vol% or more and 100 vol% or less, preferably 30 vol% or more and 100 vol% or less, more preferably 50 vol% or more and 100 vol% or less, More preferably, it is 80 vol% or more and 100 vol% or less, and most preferably 90 vol% or more and 100 vol% or less. Furthermore, it is possible to effectively suppress reoxidation by reducing the concentration of oxygen contained in the reducing gas atmosphere. Therefore, in the present invention, it is a reducing atmosphere, and the oxygen concentration is 0 vol% or more and 8 vol% or less, more preferably 0 vol% or more and 5 vol% or less, and preferably 0 vol% or more and 1 vol% or less. More preferably, it is most preferably 0 vol% or more and 0.1 vol% or less. Although the inert atmosphere and reducing atmosphere in the present invention have been described above, the inert atmosphere is preferable from the viewpoint of the apparatus for safety.

  Note that the periphery of the resist layer is an inert atmosphere or a reducing atmosphere, as described above, the atmosphere (inert gas concentration or reducing gas concentration) in the chambers 11 and 21 of the exposure apparatuses 1 and 2 (exposure chamber). ) May be achieved, but an inert gas and / or reducing gas may be sprayed onto the resist layer to locally control the atmosphere (inert gas concentration or reducing gas concentration) in the vicinity of the resist layer.

  As described above, the description for achieving an inert atmosphere and / or a reducing atmosphere has been described. However, a plurality of gas inlets of the apparatus can be provided according to the number of gases used, or a plurality of types can be mixed. By using the gas cylinder (mixed gas cylinder), the gas inlet of the apparatus can be made one.

  The wavelength of the laser beam used for the laser pickup units 13 and 23 for exposing the resist layer is preferably 150 nm or more and 550 nm or less. Further, it is preferable to use a semiconductor laser from the viewpoints of downsizing of the exposure apparatuses 1 and 2 and availability. The wavelength is preferably 350 nm or more and 550 nm or less. When the wavelength is shorter than 350 nm, the output of the laser beam becomes small and the resist layer cannot be exposed. On the other hand, when the wavelength is longer than 550 nm, the spot diameter of the laser beam cannot be made 500 nm or less, and a small exposed portion cannot be formed.

On the other hand, it is preferable to use a gas laser in order to reduce the spot size and form a small exposed portion. In particular, gas lasers of XeF, XeCl, KrF, ArF, and F ₂ are preferable because they have a short wavelength of 351 nm, 308 nm, 248 nm, 193 nm, and 157 nm and can be condensed into a very small spot size.

  As the exposure laser, a second harmonic, a third harmonic, and a fourth harmonic of an Nd: YAG laser can be used. The wavelength of the second, third, and fourth harmonics of the Nd: YAG laser is 532 nm, 355 nm, and 266 nm, respectively, and a small spot size can be obtained.

  In the exposure apparatuses 1 and 2 according to the present invention, a flat plate base as a member to be processed having a base material and a resist layer provided on the base material and containing a heat-reactive resist material that undergoes a reduction reaction by heating. The material 12 and the sleeve base material 22 are exposed to laser light. The heat-reactive resist material used in the exposure apparatuses 1 and 2 according to the present invention can be any heat-reactive resist material that undergoes a reduction reaction by heating and is used in so-called thermal lithography. Is preferred.

The exposure apparatuses 1 and 2 according to the present invention are particularly suitable for inorganic resist materials such as CuO, Co ₃ O ₄ , and BaO ₂ that reoxidize when reduced by heating and cooled in the atmosphere. This is effective when a member to be processed using a resist material as a heat-reactive resist material is subjected to laser exposure.

  The thickness of the resist layer is preferably 5 nm or more and 1 μm or less. When the film thickness of the resist layer is too thin, the resist layer cannot sufficiently absorb the irradiated laser beam, so that the temperature is not raised to a temperature necessary for reduction. For this reason, patterning by exposure cannot be performed well. When the film thickness of the resist layer is too thick, a temperature distribution is formed in the thickness direction, and the regions to be reduced above and below the resist layer are different. For this reason, accurate patterning cannot be performed. From the above, the film thickness of the resist layer is 5 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 5 nm to 100 nm, and most preferably 10 nm to 100 nm.

  The resist layer (film) is preferably formed by a vapor phase method such as vapor deposition, sputtering, or CVD. Sputtering is particularly preferred from the standpoints of adjusting the composition of the resist film, film thickness uniformity, film formation rate, and the like.

Next, an outline of an exposure process using the exposure apparatus 1 according to the above embodiment will be described.
First, the flat substrate 12 is connected to the spindle motor 14 and placed in the chamber 11. Next, the control unit 20 controls the supply amount of the inert gas and the reducing gas from the gas supply source 17 and the discharge amount of oxygen from the chamber 11 by the vacuum pump 19, so that the inside of the chamber 11 is inactive. Control to atmosphere or reducing atmosphere. Next, while the flat plate base 12 is rotated by the spindle motor 14, the laser pickup unit 13 is moved by the axis control stage 15 to irradiate a predetermined region of the flat plate base 12 with a laser beam for a predetermined heating period t1. To do. Next, in a state where the chamber 11 is in an inert atmosphere or a reducing atmosphere, the region of the flat substrate 12 irradiated with the laser light is cooled for a predetermined cooling period t2. Finally, the exposure process is completed by taking out the cooled flat substrate 12 from the chamber 11. The exposure process can be performed in the same manner for the operation of the exposure apparatus 2.

  In the exposure process using the exposure apparatus 1 described above, the inside of the chamber 11 is set to an inert atmosphere or a reducing atmosphere before the laser pickup unit 13 irradiates the laser beam. However, the atmosphere in the chamber 11 is at least heated. As long as the re-oxidation of the heat-reactive resist material reduced by the step can be suppressed, the control may be performed after the laser beam irradiation or during the laser beam irradiation.

  Thus, in the exposure apparatuses 1 and 2 according to the present embodiment, after the heat-reactive resist material of the resist layer of the flat plate base material 12 or the sleeve base material 22 is partially reduced by heating with laser light. Even in the cooling period t2, the oxygen concentration around the heat-reactive resist material is low, the inert gas is in a predetermined concentration (inert atmosphere), or the reducing gas is in a predetermined concentration (reduction) Sex atmosphere). As a result, reoxidation of the heat-reactive resist material after exposure is suppressed, and it becomes possible to suppress a decrease in development difference when developing with an acid solution or an alkali solution after exposure, thereby forming a fine pattern. It becomes possible.

  In the present invention, an etching layer can be further provided between the resist layer and the substrate. In general, optical materials, films, and the like are required to have a fine pattern with a high aspect ratio (a value obtained by dividing the groove depth by the groove opening width), and sometimes have an aspect ratio of 10 or more. . However, the depth of the groove in the film thickness direction is the same as the depth of the groove in the depth direction as it is. Therefore, in order to form a deep groove, it is necessary to increase the thickness of the resist layer. is there. However, as the film thickness increases, the uniformity in the film thickness direction due to exposure is lost, and as a result, the processing accuracy of the fine pattern not only in the depth direction but also in the film surface direction decreases.

  When it is desired to form a pattern in which the groove depth is increased along with the fine pattern shape, a film having a thickness corresponding to the groove depth to be formed under these resist layers, that is, an etching layer is formed in advance, and the etching layer After obtaining a laminate having a resist layer formed thereon, first, only the resist layer is exposed and developed to give a pattern shape to the resist layer. A method of forming a deep groove in the underlying etching layer using the patterned resist layer as a mask can be considered. By using this method, it is possible to produce an aspect ratio according to need, so that development in application can be expanded.

  Further, in the present invention, the etching layer is a layer that is etched by dry etching using a fluorine-based gas with a resist layer as a mask and is given a desired pattern. Therefore, the etching layer is dry-etched using fluorine-based gas. A material to be etched that is easily etched is preferable.

  The material to be etched used for the etching layer in the present invention is not particularly limited. For example, Si, Ta, Ge, Te, and P and oxides, nitrides, carbides, and sulfides thereof, Mo, W, Ta, and the like. In particular, Si, Ta and their oxides, nitrides and carbides are preferable from the viewpoint of film formation, stability over time, strength, cost, etc., and Si and its oxides and nitrides. And carbides are more preferred. The etching layer is preferably one that can be anisotropically or isotropically etched by dry etching, has flatness, and has high adhesion to a heat-reactive resist material or a substrate. For example, when an etching layer is formed using a sputtering method, it is effective to lower the pressure during sputtering for planarization. For improving the adhesion, the substrate is subjected to reverse sputtering treatment or the stress of the film is reduced. Examples of effective methods include performing a reduction process and newly introducing an adhesion layer.

The apparatus used in the dry etching process is not particularly limited as long as it can introduce a dry etching gas in a vacuum, can form plasma, and can perform an etching process. However, a commercially available dry etching apparatus, RIE apparatus, An ICP device or the like can be used. The gas type, time, power, etc. for performing the dry etching treatment can be appropriately determined depending on the type of the heat-reactive resist material, the type of the etching layer, the thickness of the etching layer, the etching rate of the etching layer, and the like. For example, CF ₄ , CHF ₃ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , C ₄ F ₁₀ , C ₅ F ₈ , C ₅ F ₁₀ , CH ₂ F ₂ , CCl ₂ Examples thereof include fluorocarbons such as F ₂ , NF ₃ , SF ₆ , and CF ₃ Br and mixed gases thereof, and those obtained by mixing gases such as Ar, O ₂ , H ₂ , N ₂ , and CO with these gases. Further, if necessary, HBr, HBr, HCl, HI, BBr ₃ , BCI ₃ , CI ₂ , SiCl ₄ , etc., which are halogen-based gases other than F, and mixed gases thereof, and further, Ar, O ₂ A mixture of gases such as H ₂ , N ₂ , and CO can also be used. Furthermore, it is preferable that the above-mentioned heat-reactive resist material and the material to be etched are in an amorphous state or a microcrystalline state.

  The resist layer can be formed into a fine pattern through the steps of film formation, exposure and development, but is preferably in an amorphous state or a microcrystalline state at the stage of film formation. This is because if there are coarse crystal particles in the exposed or unexposed areas, the boundary between the portion that is dissolved by development and the portion that does not dissolve is easily affected by the coarse crystal particles, resulting in a clear and uniform pattern. This is because it becomes difficult to obtain. Therefore, in the present invention, the resist material is preferably in an amorphous state or a microcrystalline state. In the present invention, a crystal state in which the boundary between the dissolved portion and the undissolved portion is unclear and does not become nonuniform is called microcrystal.

  Furthermore, in the etching layer, for the same reason as described above, in order to prevent the interface at the time of stacking from becoming unclear, the boundary between the portion that is not dry-etched and the portion that is not dry-etched at the time of dry etching is also unclear. In order to prevent this, the material to be etched is preferably in an amorphous state or a microcrystalline state. Also in this case, a crystal state in which the boundary is unclear and does not make it non-uniform is called microcrystal.

  In the heat-reactive resist material and the material to be etched according to the present invention, other elements may be added to the selected heat-reactive resist material and the material to be etched in order to obtain the amorphous state and the microcrystalline state. Elements that can be added in the present invention are Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Zn, Ga, Ru, Pd, Ag, Cd, Hf, Ta, W, Pt, Au, C, and B are preferable, but there is no particular limitation in the case of addition that does not significantly deteriorate the thermal reaction type resist characteristics and dry etching characteristics that form a fine pattern even with other elements. . Furthermore, in the present invention, in the case where the addition is performed to such an extent that the resist characteristics and the dry etching characteristics are not significantly deteriorated, it is effective to add nitrogen or oxygen at the time of film formation to obtain an amorphous state or a microcrystalline state.

  The nanoimprint mold according to the present invention can be manufactured by the above-described fine pattern forming method. For example, the nanoimprint mold exposes a workpiece on which a resist layer containing a heat-reactive resist material is formed using the exposure apparatuses 1 and 2, and then develops the resist in an unexposed portion. It can manufacture by performing the process to remove. In the development processing, an acid solution, an alkaline solution, a complexing agent, or the like can be used. As the acid solution, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, oxalic acid, hydrofluoric acid, ammonium nitrate, etc. can be used. As the alkaline solution, sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, TMAH ( Tetramethylammonium hydroxide) can be used. As the complexing agent, a general solution such as a solution of oxalic acid, ethylenediaminetetraacetic acid and a salt thereof can be used alone or as a mixed solution. It is also possible to add a potential adjusting agent such as hydrogen peroxide or manganese peroxide to the developer. Furthermore, it is also possible to improve the developability by adding a surfactant or the like to the developer. Depending on the resist material, development may be performed first with an acid developer and then with an alkali developer.

(Example)
Next, the present invention will be described in detail based on examples carried out to clarify the effects of the present invention. In addition, this invention is not limited at all by the following examples and comparative examples. First, the evaluation method used in this example will be described.

(LER)
LER (Line Edge Roughness) is an index indicating the disturbance of the pattern, and indicates the size of the unevenness formed on the wall surface of the pattern. The LER was derived by observing the surface of the resist after development with SEM (scanning electron microscope), and the obtained image was derived according to SEMI P47-0307 described in SEMI International Standards. If the value of LER exceeds 7 nm, the edge becomes very unclear and a clear pattern shape cannot be obtained.

[Example 1]
A CuO resist, which is a heat-reactive resist material, was formed into a 20 nm film on a φ2 inch glass flat substrate by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After setting the sample, the inside of the chamber was evacuated to 10 Pa or less. At this time, the O ₂ concentration in the chamber was 0.01 vol%. For the exposure, a semiconductor laser having a wavelength of 405 nm, an N.P. A. Used a 0.85 pickup. At this time, the spot size was 430 nm. The emitted laser light was reflected on the sample surface, and the reflected light intensity was monitored to adjust the position of the objective lens, and autofocusing was performed so that the laser light became spot size on the resist layer. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. The developer solution was 0.3 wt. %, Hydrogen peroxide 0.2 wt. %, Surfactant 0.1 wt. % (Trade name Adecatol SO-135) added aqueous solution was used. The development time was 4 minutes.

  When the surface shape of the heat-reactive resist (resist layer) developed in this way was observed with an SEM (scanning electron microscope), the LER was 4 nm as shown in Table 1 below, and the edges were very clear. It was confirmed that a groove shape was formed.

[Example 2]
A CuO resist, which is a heat-reactive resist material, was formed to a thickness of 20 nm on a flat glass substrate having a diameter of 2 inches by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After loading samples, after evacuating the chamber to 0.1 Pa, repeated three times to flow a 99.999% pure _{N 2} gas, the final chamber pressure was ¹⁰ 6 Pa. At this time, the O ₂ concentration in the chamber was 0.03 vol%. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. Development was performed in the same manner as in Example 1.

  When the surface shape of the heat-reactive resist (resist layer) developed in this way was observed with an SEM (scanning electron microscope), the LER was 3 nm as shown in Table 1 below, and the edges were very clear. It was confirmed that a groove shape was formed.

[Example 3]
A Co ₃ O ₄ resist, which is a heat-reactive resist material, was formed to a thickness of 20 nm on a flat glass substrate having a diameter of 2 inches by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After setting the sample, evacuation was performed with a vacuum pump while flowing 99.999% purity nitrogen gas into the chamber, and the pressure in the chamber was adjusted to 10 ⁶ Pa. After 1 hour, the O ₂ concentration in the chamber was 0.2 vol%. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 350 nm, and exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. The developer is a 3.4 wt.% Oxalic acid aqueous solution, hydrogen peroxide 2 wt. % Aqueous solution was used. The development time was 15 minutes.

  When the surface shape of the heat-reactive resist (resist layer) developed in this way was observed with an SEM (scanning electron microscope), the LER was 4 nm as shown in Table 1 below, and the edges were very clear. It was confirmed that a groove shape was formed.

[Example 4]
A BaO ₂ resist, which is a heat-reactive resist material, was formed to a thickness of 20 nm on a φ2 inch glass flat substrate by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After setting the sample, the exhaust valve was opened and nitrogen gas with a purity of 99.999% was allowed to flow into the chamber. After 2 hours, the O ₂ concentration in the chamber was 0.09 vol%. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. As the developer, a pH 1 aqueous hydrochloric acid solution was used. The development time was 1 minute.

  When the surface shape of the heat-reactive resist (resist layer) developed in this way was observed with an SEM (scanning electron microscope), the LER was 7 nm as shown in Table 1 below, and the edges were very clear. It was confirmed that a groove shape was formed.

[Example 5]
A SiO ₂ film having a thickness of 250 nm and a CuO resist film having a thickness of 20 nm were sequentially formed on a φ2 inch glass flat plate substrate by a sputtering method. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After setting the sample, the exhaust valve was opened and nitrogen gas with a purity of 99.999% was allowed to flow into the chamber. After 2 hours, the O ₂ concentration in the chamber was 0.09 vol%. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. The developer solution was 0.3 wt. %, Hydrogen peroxide 0.2 wt. %, Surfactant 0.1 wt. % (Trade name Adecatol SO-135) added aqueous solution was used. The development time was 4 minutes. Samples were developed the dry etching was performed by SF _6. (Dry etching conditions)

  When the surface shape of the heat-reactive resist (resist layer) and the etching layer thus dry-etched was observed with an SEM (scanning electron microscope), the LER was 5 nm as shown in Table 1 below. It was confirmed that a groove shape with clear edges was formed.

[Example 6]
A CuO resist film having a thickness of 20 nm was formed on a glass cylindrical substrate having a diameter of 80 mm and a length of 100 mm by sputtering. This sample was directly connected to the spindle motor in the chamber. After setting the sample, the exhaust valve was opened, and nitrogen gas having a purity of 99.999% was allowed to flow into the chamber and left to stand. After 2 hours, the O ₂ concentration in the chamber was 0.06 vol%. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the feed pitch in the longitudinal direction of the cylindrical substrate was 250 nm, and exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. The developer solution was 0.3 wt. %, Hydrogen peroxide 0.2 wt. %, Surfactant 0.1 wt. % (Trade name Adecatol SO-135) added aqueous solution was used. The development time was 4 minutes.

  A fine shape was transferred from a glass cylindrical base material in which the heat-reactive resist developed in this way forms a fine structure using a UV resin and a PET film. When the surface shape of the transferred sample was observed with an SEM (scanning electron microscope), it was confirmed that a groove shape with a very clear edge was formed with an LER of 5 nm as shown in Table 1 below.

[Example 7]
Except for changing the nitrogen gas used in Example 2 to argon gas, all the investigations were performed under the same conditions. The O ₂ concentration in the chamber was 0.03 vol%.

  At this time, when the surface shape of the heat-reactive resist (resist layer) was observed with an SEM (scanning electron microscope), the groove shape with a very clear edge was 3 nm as shown in Table 1 below. It was confirmed that it was formed.

[Example 8]
Except that the nitrogen gas used in Example 2 was changed to methane, the examination was performed under the same conditions. The methane concentration in the chamber was 99.9 vol%.

  At this time, when the surface shape of the heat-reactive resist (resist layer) was observed with an SEM (scanning electron microscope), the groove shape with an extremely clear edge was 5 nm as shown in Table 1 below. It was confirmed that it was formed.

[Example 9]
A CuO resist, which is a heat-reactive resist material, was formed into a 20 nm film on a φ2 inch glass flat substrate by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After setting the sample, the exhaust valve was opened, and carbon monoxide gas having a purity of 99.9% was allowed to flow into the chamber as a reducing gas. After 2 hours, the concentration of carbon monoxide in the chamber was 95.5 vol%. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. The developer solution was 0.3 wt. %, Hydrogen peroxide 0.2 wt. %, Surfactant 0.1 wt. % (Trade name Adecatol SO-135) added aqueous solution was used. The development time was 4 minutes.

  When the surface shape of the heat-reactive resist (resist layer) developed in this way was observed with an SEM (scanning electron microscope), the LER was 4 nm as shown in Table 1 below, and the edges were very clear. It was confirmed that a groove shape was formed.

[Comparative Example 1]
A CuO resist film having a thickness of 20 nm was formed on a flat glass substrate having a diameter of 2 inches by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After chucking, exposure was performed in the atmosphere. The same pickup as in Example 1 was used for exposure and autofocus was applied. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. The developer solution was 0.3 wt. %, Hydrogen peroxide 0.2 wt. %, Surfactant 0.1 wt. % (Trade name Adecatol SO-135) added aqueous solution was used. The development time was 4 minutes.

  When the surface shape of the heat-reactive resist (resist layer) developed in this manner was observed with an SEM (scanning electron microscope), the LER was 9 nm as shown in Table 1 below, and the unevenness of the edges was not large. It was confirmed that a clear groove shape was formed.

[Comparative Example 2]
A CuO resist film having a thickness of 20 nm was formed on a flat glass substrate having a diameter of 2 inches by sputtering. The sample was chucked by chucking with the center aligned on a stage directly connected to the spindle motor in the chamber. After setting the sample, the inside of the chamber was evacuated to 5 × 10 ⁴ Pa. At this time, the O ₂ concentration was approximately 10 vol%. For the exposure, a semiconductor laser having a wavelength of 405 nm, an N.P. A. Used a 0.85 pickup. At this time, the spot size was 430 nm. The emitted laser light was reflected on the sample surface, and the reflected light intensity was monitored to adjust the position of the objective lens, and autofocusing was performed so that the laser light became spot size on the resist layer. The spindle motor was rotated and the laser beam was irradiated with DC at a linear velocity of 7 m / s. At this time, the laser beam output was 8 mW, the radial feed pitch was 250 nm, and the exposure was performed with a width of 2 mm by spiral exposure.

  Subsequently, the heat-reactive resist exposed by the exposure machine was developed. For the development, development by a wet process was applied. Developer is 0.3 wt.% Ammonium oxalate in water. %, Hydrogen peroxide 0.2 wt. %, Surfactant 0.1 wt. % (Trade name Adecatol SO-135) added aqueous solution was used. The development time was 4 minutes.

  When the surface shape of the heat-reactive resist (resist layer) developed in this manner was observed with an SEM (scanning electron microscope), the LER was 9 nm as shown in Table 1 below, and the unevenness of the edges was not large. It was confirmed that a clear groove shape was formed.

  As shown in Table 1, when the inside of the chamber was decompressed to reduce the oxygen concentration (Example 1), and when the inside of the chamber was decompressed and replaced with nitrogen (Example 2), the inside of the chamber was introduced while introducing nitrogen. The LER was good in all cases where oxygen was discharged (Example 3). In addition, when exposed under a nitrogen stream (Examples 4 to 6), when the pressure in the chamber was reduced and replaced with argon (Example 7), the LER was also good. Moreover, when methane was used as the reducing gas, the LER was good as in the case of the inert gas (Example 8), and when the exposure was performed under a carbon monoxide stream, the inert gas was used. Compared with the case of Example 1- Example 7, although oxygen concentration was relatively high, LER was favorable (Example 9). This is presumably because the oxidation of the resist material was suppressed by carbon monoxide. On the other hand, when the oxygen concentration was high, LER increased. This is thought to be because the difference in development was reduced because the resist material in the exposed area was oxidized during the cooling period after exposure (Comparative Example 1 and Comparative Example 2).

  As described above, according to the exposure apparatuses 1 and 2 according to the above-described embodiment, laser light irradiation is performed by reducing the oxygen concentration in the vicinity of the resist layer of the workpiece or reducing the reducing gas concentration within a predetermined range. Since subsequent re-oxidation of the resist layer can be suppressed, it is possible to form a good fine pattern even after exposure. As a result, periodic grooves and holes of 1 μm or less can be accurately formed, so that optical devices such as a wire grid polarizer and a moth-eye type antireflection film can be formed.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  INDUSTRIAL APPLICABILITY The present invention has an effect that re-oxidation of a heat-reactive resist after exposure can be suppressed, a reduction in development difference can be suppressed, and a fine exposure pattern can be accurately formed. Can be suitably used for forming optical devices such as wire grid polarizers having holes and holes, and moth type antireflection films.

DESCRIPTION OF SYMBOLS 1, 2 Exposure apparatus 11, 21 Chamber 12 Flat base material 13, 23 Laser pick-up unit 14, 24 Spindle motor 15, 25 Uniaxial control stage 16, 18, 26, 28 Valve 17, 27 Gas supply source 19, 29 Vacuum pump 20, 30 Control unit 22 Sleeve base material

Claims (13)

A fine pattern forming method for forming a pattern on a resist layer provided on a substrate and comprising a heat-reactive resist material that undergoes a reduction reaction by heating,
A reduction step comprising: a heating period for heating and reducing a predetermined region of the resist layer; and a cooling period for cooling the predetermined region of the resist layer in an inert atmosphere or a reducing atmosphere; and the resist layer And a development step of developing the fine pattern.   2. The fine pattern forming method according to claim 1, wherein in the cooling period, the oxygen concentration in the vicinity of the resist layer is in the range of 0 vol% to 5 vol% as the inert atmosphere.   3. The fine pattern according to claim 1, wherein an inert gas concentration in the vicinity of the resist layer is in a range of 95 vol% to 100 vol% as the inert atmosphere in the cooling period. Forming method.   4. The inert gas according to claim 1, wherein the inert gas is at least one selected from the group consisting of nitrogen, carbon dioxide, helium, argon, krypton, xenon, radon, and fluorocarbon. A method for forming a fine pattern according to 1.   2. The fine pattern forming method according to claim 1, wherein the reducing gas concentration in the vicinity of the resist layer is in the range of 10 vol% to 100 vol% as the reducing atmosphere in the cooling period.   The reducing gas concentration in the vicinity of the resist layer in the cooling period is in the range of 10 vol% to 100 vol%, and the oxygen concentration is in the range of 0 vol% to 8 vol%. 2. The fine pattern forming method according to 1.   The reducing gas is selected from the group consisting of hydrogen, carbon monoxide, sulfur dioxide, ammonia, formaldehyde, saturated hydrocarbon gas having 1 to 5 carbon atoms, and unsaturated hydrocarbon gas having 1 to 5 carbon atoms. 7. The method for forming a fine pattern according to claim 5, wherein at least one selected is selected.   8. The method for forming a fine pattern according to claim 1, wherein the heat-reactive resist material is an inorganic resist material.   The method for forming a fine pattern according to any one of claims 1 to 8, wherein the substrate has a roll shape or a plate shape.   An exposure apparatus that forms a fine pattern on a work material having a base material, and a resist layer that is provided on the base material and includes a heat-reactive resist material that undergoes a reduction reaction by heating. An exposure chamber containing a material; an irradiation unit that irradiates a predetermined region of the resist layer of the work material in the exposure chamber with a laser beam; an exhaust unit that exhausts oxygen in the exposure chamber; and the exhaust unit And a controller for controlling the oxygen concentration in the exposure chamber. After irradiating a predetermined region of the resist layer of the material to be processed with laser light, the exposure chamber is depressurized for a predetermined cooling period to reduce oxygen. An exposure apparatus characterized in that the density is in the range of 0 vol% to 5 vol%.   An exposure apparatus that forms a fine pattern on a work material having a base material, and a resist layer that is provided on the base material and includes a heat-reactive resist material that undergoes a reduction reaction by heating. An exposure chamber that contains a material; an irradiation unit that irradiates a predetermined region of the resist layer of the material to be processed in the exposure chamber; an exhaust unit that exhausts oxygen in the exposure chamber; A gas supply unit configured to supply an inert gas or a reducing gas; and a control unit configured to control an oxygen concentration in the exposure chamber by the exhaust unit and the gas supply unit. An exposure apparatus characterized in that, after irradiating the region with laser light, the exposure chamber is made an inert atmosphere or a reducing atmosphere for a predetermined cooling period.   12. The exposure apparatus according to claim 10, wherein the oxygen concentration in the exposure chamber is reduced using an oxygen adsorbent.   A mold for nanoimprinting, which is obtained by using the method for forming a fine pattern according to any one of claims 1 to 9.

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