JP2007017961A - Near-field exposure mask, method of producing the mask, near-field exposure apparatus having the mask, and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a near-field exposure mask to be used for close-contact exposure using near-field light, that can suppress multiple reflection between a light blocking layer and an exposure object and has high durability against corrosion by an acid produced in the resist. <P>SOLUTION: The near-field exposure mask has a light blocking layer formed on a substrate, the layer having an opening with an opening width narrower than a wavelength of an exposure light source, for exposing an exposure object by use of near-field light to be produced at the opening while the mask comes into contact with the exposure object. The light blocking layer comprises a film containing silicon in a range from 50% to 100% in mole fraction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a near-field exposure mask, a method for manufacturing the mask, a near-field exposure apparatus including the mask, and a resist pattern forming method.

  In recent years, in the field of various electronic devices that require fine processing, such as semiconductor devices, there is an increasing demand for higher density and higher integration of devices. Has become essential.

  In such a semiconductor device manufacturing process, the photolithography process plays an important role in forming a fine pattern.

  However, since most of the current photolithography process is performed by reduced projection exposure, the resolution is limited by the diffraction limit of light, and only a spatial resolution of about one third of the wavelength of the light source can be obtained. . For this reason, by using a KrF excimer laser, an ArF excimer laser, or the like as an exposure light source, the wavelength can be shortened and fine processing of about 100 nm is possible.

  With such shortening of the wavelength, various measures have been taken for the photomasks and the like used there, since the conventional ones have insufficient light shielding properties.

  For example, Patent Document 1 and Patent Document 2 propose a photomask using silicon as a light-shielding film because conventional chrome-based photomasks have insufficient light-shielding properties with respect to a KrF excimer laser (wavelength 248 nm). Yes.

  However, what is disclosed here is a mask for reduced projection exposure.

  As described above, in photolithography in which the wavelength of the light source is shortened, in addition to the above-described photomask and the like, the size of the device, the development of the lens in the wavelength region, the cost of the device, the cost of the corresponding resist, etc. Many issues to be solved have emerged.

  On the other hand, a method using near-field light has been proposed in order to perform fine processing with a resolution equal to or lower than the wavelength using light.

  In the case of such near-field light, since it is not restricted by the diffraction limit of light, a spatial resolution of one third or less of the light source wavelength can be obtained. Further, if a mercury lamp or a semiconductor laser is used as the light source, the light source itself can be made small, so that the apparatus configuration can be downsized and the cost can be reduced.

  As one of lithography methods using near-field light, for example, there is one disclosed in Patent Document 3.

In Patent Document 3, a near-field exposure mask having a light-shielding layer in which an opening narrower than a light source wavelength is formed is brought into close contact with a resist to a near-field region of 100 nm or less, and a fine pattern on the mask is resisted by batch exposure. Disclosed is a method for transcription.
JP-A-6-095363 JP-A-6-095358 Japanese Patent Laid-Open No. 11-145051

  By the way, in Patent Document 3 in which exposure is performed with a near-field exposure mask in close contact with a resist, a part of the near-field light generated at the opening of the light shielding layer is converted into propagation light. Even if the incident light is perpendicularly incident on the light shielding layer, the propagating light generated by conversion from the near-field light has low directivity and therefore propagates in an oblique direction. This propagated light propagates in the object to be exposed, is reflected on the substrate surface, and is further reflected by the light shielding layer. As a result of propagating through the object to be exposed while being subjected to multiple reflections, there is a possibility that the propagated light reaches the adjacent pattern portion and affects the pattern.

  In addition, depending on the resist used, the adhesion of the mask to the light-shielding layer is high, and there is a possibility that the mask is damaged when the mask is peeled off or the resist is peeled off from the substrate.

  In addition, when a resist that develops a development contrast by a reaction using an acid generated by exposure as a catalyst, such as a chemically amplified resist or a photocationic polymerization resist, the light shielding layer of the mask is corroded by the generated acid. Therefore, the possibility of shortening the life of the mask cannot be denied.

The near-field exposure mask provided by the present invention has a light-shielding layer having an opening whose opening width is narrower than the wavelength of the exposure light source on a substrate, and is covered with near-field light generated in the opening. A near-field exposure mask for exposing the object to be exposed while being in contact with the object to be exposed,
The light-shielding layer is composed of a film containing silicon in a range of 50% to 100% by mole fraction.

  A method of manufacturing a near-field exposure mask provided by the present invention is a method of manufacturing a near-field exposure mask for performing exposure in a state of being in contact with an object to be exposed by near-field light. A step of forming a light-shielding layer using a film containing a molar fraction of 50% or more and 100% or less; and a step of forming an opening in the light-shielding layer with an opening width narrower than the wavelength of the exposure light source; It is characterized by having.

  The present invention includes a near-field exposure apparatus, a resist pattern forming method, and a device manufacturing method.

  The near-field exposure apparatus of the present invention comprises a near-field exposure mask and means for bringing the light shielding layer of the mask into contact with an object to be exposed, and irradiates light from the opposite side of the light shielding layer of the mask, In a near-field exposure apparatus that performs contact exposure on an object to be exposed by near-field light generated on the object side, the near-field exposure mask is constituted by the near-field exposure mask of the present invention.

  The resist pattern forming method of the present invention uses a near-field exposure mask, and performs exposure in a state in which the mask is in contact with the resist. In the resist pattern forming method for forming a resist pattern, the near-field exposure mask Further, the near-field exposure mask of the present invention is used.

  The device manufacturing method of the present invention is a device manufacturing method of manufacturing a device using a substrate for device manufacturing, the step of applying a photosensitive resist on the substrate, and the proximity of the resist and the present invention. A step of contacting a field exposure mask; a step of irradiating the resist with light from an exposure light source through the near-field exposure mask; a step of developing the resist after light irradiation; and Etching the substrate based on a resist.

  According to the present invention, it is possible to suppress the occurrence of multiple reflections between the light-shielding layer and the object to be exposed, easy peeling from the resist in the contact exposure, and high durability against acid corrosion occurring in the resist. It is possible to provide a near-field exposure mask having a property.

The near-field exposure mask provided by the present invention has a light-shielding layer having an opening whose opening width is narrower than the wavelength of the exposure light source on a substrate, and is covered with near-field light generated in the opening. A near-field exposure mask for exposing the object to be exposed while being in contact with the object to be exposed,
The light-shielding layer is composed of a film containing silicon in a range of 50% to 100% by mole fraction.

  According to the present invention, it is possible to suppress the occurrence of multiple reflections between the light-shielding layer and the object to be exposed, easy peeling from the resist in the contact exposure, and high durability against acid corrosion occurring in the resist. It is possible to provide a near-field exposure mask having a property.

  JP-A-6-095363 and JP-A-6-095358 mentioned above propose a light-shielding film using silicon for a photomask used in a photolithography process in conventional reduction projection exposure. However, as the light source wavelength becomes shorter, the conventional chrome-based photomasks are merely due to inconveniences such as insufficient light shielding properties with respect to KrF excimer laser (wavelength 248 nm).

  On the other hand, the present invention is the result of intensive studies by the present inventors in order to solve the occurrence of multiple reflections peculiar to near-field exposure, the problem of peeling from the resist, and the corrosion caused by the acid generated in the resist. It was discovered for the first time.

  In the embodiment, the present invention can be further configured as follows.

  The near-field exposure mask of the present invention includes one in which the light shielding layer is made of amorphous silicon, polycrystalline silicon, or single crystal silicon. Moreover, the thing with the transmittance | permeability with respect to the light source wavelength for exposure of a light shielding layer is 0.1 or less is included.

  Further, the light shielding layer includes a structure in which the surface of a film containing silicon is subjected to water repellency and oil repellency treatment.

  In the water and oil repellency treatment, a fluorine-based silane coupling agent may be attached to the surface of the film containing silicon.

Further, the fluorine-based silane coupling agent, the general formula can be composed of a compound represented by _{Rf m R n SiX 4-m} -n. Here, Rf is an alkyl group in which part or all of hydrogen is fluorine-substituted, R is an alkyl group, Si is silicon, X: an alkoxyl group, a halogen group or an amino group, and 1 ≦ m ≦ 3, 0 ≦ n ≦ 2, 1 ≦ m + n ≦ 3.

  In the water repellency and oil repellency treatment, the surface of the silicon-containing film may be halogenated by exposing the halogen-containing gas to plasma.

  The manufacturing method of a near-field exposure mask according to the present invention is a manufacturing method of a near-field exposure mask for performing exposure in a state of being in contact with an object to be exposed by near-field light. A step of forming a light shielding layer using a film that is contained in a range of 50% or more and 100% or less, and a step of forming an opening in the light shielding layer whose opening width is narrower than the wavelength of the light source for exposure. It is characterized by that. Then, the present invention further includes a step of removing a part of the substrate from the side opposite to the side where the light shielding layer is formed on the substrate and forming a thin film portion for allowing light from the light source side to enter. Includes what you have.

  Moreover, what further has the process of water-repellent and oil-repellent-treating the surface of the light shielding layer in which the said opening was formed is included.

Further, in the present invention, the step of forming the light shielding layer may include a process of thinning the light shielding layer containing silicon having a predetermined thickness bonded on the substrate and forming the light shielding layer by the thin film. it can. Or it can be set as the process including the process of removing the support substrate and BOX layer from the SOI wafer joined on the board | substrate, and forming the light shielding layer by the said thin film.
In the resist pattern forming method, a resist that develops development contrast by a reaction using an acid generated by the contact exposure as a catalyst can be used as the resist. At that time, a chemically amplified resist or a cationic photopolymerization resist can be used as the resist.

  Examples of the present invention will be described below. The examples shown here are representative examples, and the present invention is not limited to the examples shown here.

[Example 1]
In Example 1, the present invention was applied to manufacture a mask by the following method for manufacturing a near-field exposure mask.

  FIG. 1 is a diagram for explaining a manufacturing process in the manufacturing method of the near-field exposure mask of this embodiment.

  Next, a procedure for producing a near-field exposure mask will be described with reference to FIG.

First, a silicon substrate 11 is prepared, and silicon nitride Si ₃ N _{4 serving} as a transparent base material 12 of a mask made of an elastically deformable thin film is formed on both surfaces by low pressure CVD (FIG. 1A). However, the substrate and the base material are not limited to these.

  Subsequently, a silicon thin film is formed on one surface side of the silicon substrate 11 to form the silicon light shielding layer 13 (FIG. 1B).

  Here, it is preferable to adjust the thickness and / or extinction coefficient of the silicon light shielding layer 13 so that the transmittance of the light shielding layer is 0.1 or less, preferably 0.01 or less with respect to the exposure wavelength. . When the transmittance is 0.1 or more, the light intensity contrast between the exposed area and the unexposed area is low, and a resist pattern with high resolution cannot be formed. The extinction coefficient can be adjusted by film forming conditions, addition of metal as described later, and the like.

The transmittance T with respect to the exposure wavelength λ of the light shielding layer having the extinction coefficient k and the thickness t is calculated by the following equation.
T = exp (-4πkt / λ)
For example, the transmittance of the light-shielding layer having a thickness of 50 nm at an exposure wavelength of 365 nm is 0.1 or less when the extinction coefficient k is 1.338 or more and 0.01 or less when the extinction coefficient k is 2.675 or more. The extinction coefficient of amorphous silicon, polycrystalline silicon, and single crystal silicon at an exposure wavelength of 365 nm is about 2.6 to 2.8.

  Here, the thickness of the light shielding layer 13 containing silicon can be, for example, 10 to 100 nm. Further, the thickness of the transparent base material 12 is preferably 0.1 to 100 μm.

  The silicon light shielding layer 13 may contain a metal or the like. In that case, it is possible to freely change the extinction coefficient of the light shielding layer by changing the composition ratio. The content ratio of silicon (atom) in the film constituting the light shielding layer employed in the mask of the present invention is in the range of 50% to 100% in terms of molar fraction, and more preferably 90% to 100%. preferable. When the content ratio is less than 50%, it is difficult to process the light shielding film. Examples of the method for forming the silicon light-shielding layer 13 include sputtering and reduced-pressure chemical vapor deposition (CVD).

  When the obtained silicon is amorphous, it may be crystallized by annealing with heat or laser. In the present embodiment, crystalline silicon is preferred for reasons of pattern processing described later.

  Next, a fine pattern 14 is formed on the silicon light shielding layer 13 (FIG. 1C). Patterning of the fine pattern 14 is performed by direct processing using a Focused Ion Beam (FIB) processing apparatus or by etching using a resist patterned by an Electron Beam (EB) drawing apparatus as a mask. In this embodiment, the opening width of the fine pattern 14 is made narrower than the wavelength of the exposure light source used for near-field exposure.

In the etching process using an EB lithography system, either directly applying the EB resist on the silicon light blocking layer 13, an oxide layer such as _SiO 2, TiO ₂ on the silicon light blocking layer 13, Cr, Ti, Au, or Al An intermediate layer such as a metal layer is formed, and an EB resist is applied thereon.

The etching of silicon and / or the intermediate layer may be dry etching or wet etching. Dry etching is performed using a gas such as CF ₄ , C ₂ F ₆ , C ₃ F ₈ , CCl ₂ F ₂ , CCl ₄ , CBrF ₃ , BCl ₃ , PCl ₃ , SF ₆ , Cl ₂ , HCl, and HBr. The wet etching is performed using an alkaline aqueous solution such as potassium hydroxide or tetramethylammonium hydroxide.

  When the crystalline silicon is wet etched, a highly anisotropic fine pattern 14 along the crystal axis can be formed.

  Here, when exposure is performed with a near-field exposure mask in close contact with the resist, depending on conditions, the mask may be in close contact with the resist, and it may be difficult to peel the mask from the resist after exposure. Therefore, in order to prevent such inconvenience and facilitate peeling after exposure, the silicon light-shielding layer 13 on which the fine pattern 14 is formed can be subjected to water and oil repellency treatments.

  The water- and oil-repellent layer formed on the silicon surface is dense and has a strong chemical bonding force with silicon, and therefore has a high water-repellent and oil-repellent effect. As a result, the durability of the near-field exposure mask is improved as an effect of the water and oil repellency treatments.

  The water repellency and oil repellency treatment can be performed using a fluorine-based silane coupling agent.

  At that time, first, a fluorine-based silane coupling agent is attached to the silicon light-shielding layer 13 under liquid phase or gas phase conditions. Adhesion under liquid phase conditions is performed by immersing the mask substrate for several minutes to several tens of minutes in a solution containing a fluorine-based silane coupling agent.

  Further, the deposition under a gas phase condition is performed by placing the mask substrate for several minutes to several tens of minutes in a vapor atmosphere of a fluorine-based silane coupling agent.

The fluorine-based silane coupling agent is a compound represented by the general formula Rf _m R _n SiX _4-mn (where Rf is an alkyl group in which some or all of the hydrogen is fluorine-substituted, R is an alkyl group, Si is silicon, X is an alkoxyl group, a halogen group or an amino group, and 1 ≦ m ≦ 3, 0 ≦ n ≦ 2, and 1 ≦ m + n ≦ 3) are particularly preferably used.

  After depositing the fluorine-based silane coupling agent, the mask substrate is allowed to stand for 1 hour or more in an environment of temperature 20 to 60 ° C. and humidity 40 to 100%. Thereby, the hydroxyl group of the natural oxide film on the silicon light-shielding layer 13 is subjected to a condensation reaction with the alkoxyl group or the halogen group of the fluorine-based silane coupling agent.

  Thereafter, it is immersed in an organic solvent solution for several minutes to remove unreacted excess fluorine-based silane coupling agent.

  As another method of water repellency and oil repellency treatment of the silicon light-shielding layer 13, surface halogenation by exposure to plasma containing halogen atoms such as fluorine, chlorine and bromine can also be used.

The mask substrate is placed in a vacuum chamber of a dry etching apparatus, and CF ₄ , C ₂ F ₆ , C ₃ F ₈ , CCl ₂ F ₂ , CCl ₄ , CBrF ₃ , BCl ₃ , PCl ₃ , SF ₆ , Cl _2. The surface of the light shielding layer silicon can be halogenated by exposure to plasma such as HCl, HBr.

  Next, the back etch hole 15 is patterned in the transparent base material 12 on the other surface side (the back surface side in the mask) of the silicon substrate 11 (FIG. 1D).

  The patterning of the back etch hole 15 can be performed by, for example, etching using the resist pattern that has been applied and exposed and developed on the transparent base material 12 as a mask.

  Thereafter, the silicon substrate 11 is subjected to crystal axis anisotropic etching using an alkaline aqueous solution such as potassium hydroxide and tetramethylammonium hydroxide (TMAH) to form a thin film mask structure having a mask thin film portion 16 (FIG. 1 ( e)).

  In this embodiment, an SOI wafer having a transparent base material formed only on the support substrate side may be used to form the structure shown in FIG. In this case, the processes after the formation of the fine pattern 14 are performed in the same manner.

[Example 2]
In Example 2, the present invention was applied, and a mask was manufactured by a manufacturing method of a near-field exposure mask different from that in Example 1.

  FIG. 2 is a diagram for explaining a manufacturing process in the manufacturing method of the near-field exposure mask of this embodiment.

  Hereinafter, a procedure for producing a near-field exposure mask will be described with reference to FIG.

  First, a transparent substrate 21 is prepared, and a silicon light shielding layer 22 is formed in the same manner as in Example 1 (FIG. 2A).

  Next, a fine pattern 23 is formed on the silicon light shielding layer 22 (FIG. 2B). Patterning of the fine pattern 23 is performed in the same manner as in the first embodiment.

  Here, it is preferable to perform water repellency and oil repellency treatment of the silicon light shielding layer 22 on which the fine pattern 23 is formed. The water and oil repellency treatments are performed in the same manner as in Example 1.

  Next, a resist 24 is applied to the side of the transparent substrate 21 where the silicon light shielding layer is not formed (FIG. 2C).

  Subsequently, a back etch hole 25 is formed by exposure and development (FIG. 2D). Thereafter, the transparent substrate 21 is etched with a hydrofluoric acid aqueous solution or the like. This etching is terminated with 0.1 to 100 μm of the transparent substrate 21 left, thereby forming a thin film mask structure having a mask thin film portion 26 that can be elastically deformed (FIG. 2E).

  According to the near-field exposure mask of the present embodiment produced in this way, the mask thin film portion 26 and the transparent substrate 21 are formed from the same substrate, so that the mask thin film portion 26 is unlikely to sag. A field exposure mask can be obtained.

[Example 3]
In Example 3, the present invention was applied, and a mask was manufactured by a method for manufacturing a near-field exposure mask having a different form from the above-described Examples.

  FIG. 3 is a diagram for explaining a manufacturing process in the manufacturing method of the near-field exposure mask of this embodiment. A procedure for manufacturing a near-field exposure mask will be described with reference to FIGS.

  First, a silicon substrate 31 is prepared, and a transparent substrate 32 such as quartz is bonded to one side (FIG. 2A).

  Subsequently, the silicon substrate 31 is thinned to a thickness of 10 to 100 nm by mechanical polishing, CMP, dry etching, or the like (FIG. 3B).

  Next, a fine pattern 33 is formed on the thinned silicon substrate 31 (FIG. 3C). Patterning of the fine pattern 33 is performed in the same manner as in the first embodiment.

  Here, it is preferable to perform water repellency and oil repellency treatment on the thinned silicon substrate 31 on which the fine pattern 33 is formed. The water and oil repellency treatments are performed in the same manner as in Example 1.

  Next, a resist 34 is applied to the side of the transparent substrate 32 where the fine pattern 33 is not formed (FIG. 3D).

  Subsequently, a back etch hole 35 is formed by exposure and development (FIG. 3E). Thereafter, the transparent substrate 2 is etched with a hydrofluoric acid aqueous solution or the like. This etching is terminated with 0.1 to 100 μm of the transparent substrate 32 left, thereby forming a thin film mask structure having a mask thin film portion 36 that can be elastically deformed (FIG. 3F).

  According to the near-field exposure mask of this example produced in this manner, the mask thin film part 36 and the transparent substrate 32 are formed from the same substrate as in the second example. Thus, it is possible to obtain a near-field exposure mask that is less likely to sag.

[Example 4]
In Example 4, the present invention was applied, and a mask was manufactured by a method for manufacturing a near-field exposure mask having a different form from the above-described Examples.

  FIG. 4 is a diagram for explaining a manufacturing process in the manufacturing method of the near-field exposure mask of this embodiment. A procedure for manufacturing a near-field exposure mask will be described with reference to FIG.

  First, an SOI wafer 41 is prepared, and a transparent substrate 42 such as quartz is bonded to one side (FIG. 4A). Although the thickness of the SOI layer of the SOI wafer 41 is preferably 10 to 100 nm, even if it is thicker than that, it is sufficient to reduce the thickness of the SOI layer in the same manner as in Example 3 after the step shown in FIG. .

  Next, the support substrate of the SOI wafer 41 is removed using an alkaline aqueous solution such as potassium hydroxide or tetramethylammonium hydroxide (TMAH) (FIG. 4B).

  Subsequently, the BOX layer is removed with a hydrofluoric acid aqueous solution or the like (FIG. 4C).

  Next, a fine pattern 43 is formed in the SOI layer (FIG. 4D).

  Patterning of the fine pattern 43 is performed in the same manner as in the first embodiment.

  Here, it is preferable to perform water and oil repellency treatment on the SOI layer of the SOI wafer 41 on which the fine pattern 43 is formed. The water and oil repellency treatments are performed in the same manner as in Example 1.

  Next, a resist 44 is applied to the side of the transparent substrate 42 where the silicon layer is not formed (FIG. 4E).

  Subsequently, a back etch hole 45 is formed by exposure and development (FIG. 4F). Thereafter, the transparent substrate 42 is etched with a hydrofluoric acid aqueous solution or the like. This etching is terminated with 0.1 to 100 μm of the transparent substrate 42 left, thereby forming a thin film mask structure having a mask thin film portion 46 that can be elastically deformed (FIG. 3F).

  According to the near-field exposure mask of the present embodiment thus manufactured, the mask thin film portion 46 and the transparent substrate 42 are formed from the same substrate as in the second embodiment. Thus, it is possible to obtain a near-field exposure mask that is less likely to sag.

  As another example of manufacturing a near-field exposure mask, a transparent substrate having a patterned silicon light-shielding layer is polished from the opposite side to the light-shielding layer to form a thin film, which is then attached to a support having a separately prepared opening. There is also a method of matching.

[Example 5]
In Example 5, a resist pattern was formed by the following resist pattern forming method using a near-field exposure mask to which the present invention was applied.

  The resist can be used regardless of positive type or negative type as long as it has photosensitivity to the light source to be used. Examples of the positive resist include diazonaphthoquinone-novolak type and chemically amplified positive type. Examples of the negative resist include a chemically amplified negative type, a cationic photopolymerization type, a radical photopolymerization type, a polyhydroxystyrene-bisazide type, a cyclized rubber-bisazide type, and a polyvinylcinnamate type. Here, when a chemically amplified positive resist and a chemically amplified negative resist are used, a pattern with high line width accuracy is formed.

  Chemically amplified resists and cationic photopolymerization resists generate an acid upon exposure. Compared to conventional near-field exposure masks that use metal as a light-shielding layer, the near-field exposure masks according to the present invention that use silicon as a light-shielding layer are less susceptible to acid corrosion, so use chemically amplified resists or photocationic polymerization resists. In near-field exposure, the durability is further high.

  The resist is applied on a substrate to be processed (device manufacturing substrate). As a substrate to be processed, a semiconductor substrate such as Si, GaAs, or InP, an insulating substrate such as glass, quartz, or BN, or one or more kinds of resist, metal, oxide, nitride, or the like on these substrates are used. A wide range of films such as a film can be used.

  The propagation depth of near-field light is usually 100 nm or less. Therefore, in order to form a resist pattern having a height of 100 nm or more by near-field photolithography, it is preferable to use a multilayer resist method. That is, it is preferable to use a two-layer resist method in which a resist having resistance to oxygen dry etching is applied on a lower resist layer that can be removed by dry etching applied on a substrate. Alternatively, it is preferable to use a three-layer resist method having a structure in which a lower resist layer that can be removed by dry etching applied onto a substrate, an oxygen plasma etching resistant layer thereon, and a resist layer applied thereon.

  The resist can be applied by using a known coating apparatus and method such as a spin coater, a dip coater, and a roller coater.

  The film thickness is comprehensively determined in consideration of the processing depth of the base substrate, the plasma etch resistance of the resist, and the light intensity profile. Usually, it is desirable to apply so as to be 10 to 300 nm after pre-baking.

  Furthermore, for the purpose of reducing the film thickness after pre-baking before the application of the resist, benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonyl acetone, isophorone, caproic acid, High boiling point solvents such as caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, ethylene glycol monophenyl ether acetate 1 or more types can also be added.

  The resist coating film is pre-baked at 80 to 200 ° C., preferably 80 to 150 ° C. For pre-baking, heating means such as a hot plate or a hot air dryer can be used. A pressure difference is provided between the upper surface and the lower surface of the mask thin film portion, and the mask and the resist are brought into close contact with each other by elastically deforming the thin film portion in the normal direction of the mask surface.

  As a light source for near-field exposure, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, a YAG laser, an Ar ion laser, a semiconductor laser, an F2 excimer laser, an ArF excimer laser, or a KrF excimer laser is used. , Visible light, etc. are used. One or more of these light sources can be used. In the present invention, light having a wavelength shorter than 365 nm can be particularly preferably used. This is because silicon has a high extinction coefficient for wavelengths shorter than 365 nm.

  Silicon has a lower reflectivity at the resist / light-shielding layer interface than metal conventionally used as a light-shielding layer. For this reason, the multiple reflection of the propagation light generated by conversion from the near-field light is suppressed, and the isolation of the pattern group is further increased.

  The near-field exposure mask having the silicon light-shielding layer 3 that has been subjected to the water-repellent and oil-repellent treatment as described above can be easily removed from the resist after the near-field exposure without causing damage to the mask or peeling of the resist from the substrate. Can be peeled off.

  After the near-field exposure, post-exposure heating is performed. The post-exposure heating is performed at 80 to 200 ° C, preferably 80 to 150 ° C. For the post-exposure heating, a heating means such as a hot plate or a hot air dryer can be used.

  The resist layer exposed in the near field is developed with an alkaline aqueous solution, an aqueous developer, an organic solvent, or the like. Examples of the development method include a dip method, a spray method, brushing, and slapping.

  In the case of increasing the aspect ratio of a resist pattern formed by near-field exposure by a two-layer resist method, oxygen plasma etching is performed using the pattern as a mask. Examples of the oxygen-containing gas used for oxygen plasma etching include oxygen alone, a mixed gas of oxygen and an inert gas such as argon, or oxygen and carbon monoxide, carbon dioxide, ammonia, dinitrogen monoxide, sulfur dioxide, and the like. A mixed gas can be used.

  In the case of increasing the aspect ratio of a resist pattern formed by near-field exposure by a three-layer resist method, the oxygen plasma etching resistant layer is etched using the pattern as a mask. As the etching, wet etching or dry etching can be applied, but dry etching is more suitable for forming a fine pattern and is more preferable.

  Examples of the wet etching agent include an aqueous hydrofluoric acid solution, an aqueous ammonium fluoride solution, an aqueous phosphoric acid solution, an aqueous acetic acid solution, an aqueous nitric acid solution, and an aqueous cerium ammonium nitrate solution, depending on the object to be etched.

Examples of the dry etching gas include CHF ₃ , CF ₄ , C ₂ F ₆ , CF ₆ , CCl ₄ , BCl ₃ , Cl ₂ , HCl, H ₂ , Ar, and the like. Used in combination.

  After etching resistant to oxygen plasma etching, oxygen plasma etching is performed in the same manner as the two-layer resist method, and the pattern is transferred to the lower resist layer.

  The substrate can be processed by dry etching, wet etching, metal deposition, lift-off or plating using the resist pattern formed as described above as a mask.

Using the substrate processing method as described above, for example, the following devices (1) to (5) or elements can be produced.
(1) Semiconductor device.
(2) A quantum dot laser device by using a GaAs quantum dot having a size of 50 nm arranged in a two-dimensional structure at 50 nm intervals.
(3) A sub-wavelength device (SWS) having an antireflection function by using a 50 nm sized conical SiO ₂ structure on a SiO ₂ substrate two-dimensionally arranged at 50 nm intervals.
(4) A photonic crystal optical device or a plasmon optical device by using a structure of 100 nm size made of GaN or metal periodically arranged in two dimensions at intervals of 100 nm.
(5) Biosensor and micrototal analysis using localized plasmon resonance (LPR) and surface-enhanced Raman spectroscopy (SERS) by using 50 nm-sized Au fine particles in a two-dimensional array on a plastic substrate at 50 nm intervals System (μTAS) element.
(6) Nanoelectromechanical systems (NEMS) such as SPM probes by using them for manufacturing sharp structures with a size of 50 nm or less used in scanning probe microscopes (SPM) such as tunnel microscopes, atomic force microscopes, and near-field optical microscopes )element.

The figure explaining the manufacturing process of the near field exposure mask in Example 1 of this invention. The figure explaining the manufacturing process of the near field exposure mask in Example 2 of this invention. The figure explaining the manufacturing process of the mask for near-field exposure in Example 3 of this invention. The figure explaining the manufacturing process of the mask for near-field exposure in Example 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Substrate 12 Transparent base material 13 Silicon light shielding layer 14 Fine pattern 15 Back etch hole 16 Mask thin film part

Claims (14)

The object to be exposed has a light-shielding layer in which an opening having an opening width narrower than the wavelength of the exposure light source is formed on the substrate, and is in contact with the object to be exposed using near-field light generated in the opening. A near-field exposure mask for performing exposure to
A near-field exposure mask, wherein the light-shielding layer is composed of a film containing silicon in a range of 50% to 100% by mole fraction.   The near-field exposure mask according to claim 1, wherein the light shielding layer is made of amorphous silicon.   The near-field exposure mask according to claim 1, wherein the light shielding layer is made of polycrystalline silicon or single crystal silicon.   The near-field exposure mask according to claim 1, wherein the light shielding layer has a transmittance of 0.1 or less with respect to the wavelength of the exposure light source.   The near-field exposure mask according to claim 4, wherein the light shielding layer has a transmittance of 0.01 or less with respect to the wavelength of the exposure light source.   The near-field exposure mask according to claim 1, wherein the light shielding layer is provided with a fluorine-based silane coupling agent on a surface thereof. A method for manufacturing a near-field exposure mask for performing exposure in a state of being in contact with an object to be exposed by near-field light, wherein silicon is contained on a substrate in a range of 50% to 100% by mole fraction. Forming a light shielding layer using a film;
A method of manufacturing a near-field exposure mask, comprising: forming an opening having an opening width narrower than a wavelength of an exposure light source in the light shielding layer.   8. The method according to claim 7, further comprising a step of removing a part of the substrate from a side opposite to the side where the light shielding layer is formed on the substrate and forming a thin film portion for allowing light from the light source side to enter. Manufacturing method of near-field exposure mask. A near-field exposure mask and means for bringing the light-shielding layer of the mask into contact with the object to be exposed; light is irradiated from the opposite side of the light-shielding layer of the mask; In a near-field exposure apparatus that performs close contact exposure on an exposed object,
2. The near-field exposure apparatus, wherein the near-field exposure mask is constituted by the near-field exposure mask according to claim 1. In the method of forming a resist pattern, using a near-field exposure mask, exposing the mask in contact with the resist, and forming a pattern in the resist.
The method for forming a resist pattern, wherein the near-field exposure mask according to claim 1 is used as the near-field exposure mask.   The resist pattern forming method according to claim 10, wherein a resist that develops development contrast by a reaction using an acid generated by the contact exposure as a catalyst is used as the resist.   The method for forming a resist pattern according to claim 11, wherein the resist is a chemically amplified resist.   The method for forming a resist pattern according to claim 11, wherein the resist is a cationic photopolymerization resist.   A device fabrication method for fabricating a device using a substrate for device fabrication, the step of applying a photosensitive resist on the substrate, and contacting the resist with the near-field exposure mask according to claim 1 A step of irradiating the resist with light from an exposure light source through the near-field exposure mask, a step of developing the resist after light irradiation, and the substrate based on the resist after development And a step of etching the device.

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