JP2005093509A - Proximity exposure mask, proximity light generating method, method of forming proximity exposure mask, proximity aligner, proximity exposure method, and method of forming micro element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proximity exposure mask, a proximity light generating method, a proximity exposure mask forming method, a proximity aligner, a proximity exposure method, and a micro element forming method wherein proximity light can be efficiently generated, and strong proximity light can be generated at a desired position. <P>SOLUTION: A proximity exposure mask is provided with a pattern composed of one or more metal micro structures which are formed on a mask mother material and smaller in size than the wavelength of exposure light, or micro openings which are formed on a light shading layer on the mask mother material and smaller in size than the wavelength of exposure light. The above metal micro structures or the above micro openings provided on the light shading layer are asymmetrical about an optional axis of symmetry in cross section vertical to the surface of the mask. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a near-field exposure mask, a near-field light generation method, a near-field exposure mask manufacturing method, a near-field exposure apparatus, a near-field exposure method, and a microelement manufacturing method.

As the capacity of semiconductor memories increases and the speed and integration of CPU processors increase, further miniaturization of photolithography becomes indispensable. In general, the limit of fine processing in an optical lithography apparatus is about the wavelength of light used. For this reason, the wavelength of light used in an optical lithography apparatus has been shortened, and near-ultraviolet lasers are currently used, and fine processing of about 0.1 μm is possible.
Although photolithography is progressing in this way, there are many problems that need to be solved, such as further shortening the wavelength of the laser and developing a lens in that wavelength region, in order to perform microfabrication of 0.1 μm or less.
On the other hand, a microfabrication apparatus using a configuration of a near-field optical microscope (hereinafter abbreviated as SNOM) has been proposed as means for enabling microfabrication of 0.1 μm or less by light. For example, it is an apparatus that performs local exposure exceeding the optical wavelength limit on a resist using a near field that oozes out from a minute slit having a size of 100 nm or less.
However, these SNOM lithographic apparatuses have a problem that throughput is not improved so much because they are configured to perform microfabrication with a single (or several) processing probe as in a single stroke. Was.
As one method for solving this problem, for example, a prism is provided on an optical mask having an aperture pattern with a wavelength equal to or smaller than that of Patent Document 1 so that light is incident at an angle of total reflection, and bleeding occurs from the total reflection surface. There has been a proposal to collectively transfer the pattern of the optical mask to the resist using the evanescent light emitted.
Japanese Patent Laid-Open No. 08-179493

By the way, when near-field light is generated using the above-described minute aperture, further improvement in the generation efficiency is desired, and it is difficult to generate a strong electric field at a desired position. However, it was not always satisfactory in obtaining the exposure pattern.
Therefore, the present invention solves the above-described problems, can generate near-field light with high efficiency, and can also generate a near-field exposure mask and a near-field that can generate strong near-field light at a desired position. An object of the present invention is to provide a light generation method, a near-field exposure mask manufacturing method, a near-field exposure apparatus, a near-field exposure method, and a microelement manufacturing method.

The present invention provides a near-field exposure mask configured as follows, a near-field light generation method, a near-field exposure mask manufacturing method, a near-field exposure apparatus, a near-field exposure method, and a microelement manufacturing method. Is.
That is, the near-field exposure mask of the present invention is a metal microstructure having a size equal to or smaller than the wavelength of light used for exposure, which is composed of a light-shielding layer formed on a mask base material, or a minute structure provided on the light-shielding layer. A near-field exposure mask having a pattern by an opening, wherein the metal microstructure has at least one of a cross section in a direction perpendicular to the mask surface and a cross section in the direction perpendicular to the mask surface of the micro opening. One is characterized by having an asymmetric cross-sectional shape with respect to an arbitrary axis of symmetry perpendicular to the mask surface.
Further, the near-field exposure mask of the present invention has a configuration in which light used for the exposure is incident from the first surface side of the mask and a photoelectric field is generated from the second surface side, and the mask is asymmetric. It can be configured to have at least one sharp apex in the vicinity of the second surface side in the cross-sectional shape. In that case, it can be set as the structure which has a 1st vertex and a 2nd vertex in the said 1st surface vicinity, and has a 3rd vertex in the said 2nd surface vicinity.
In the near-field exposure mask of the present invention, the asymmetric cross-sectional shape may be a substantially triangular shape, a substantially polygonal shape including a substantially quadrangular shape, or a substantially parallelogram shape. In addition, when the above-described substantially triangular shape is used, in the triangle having the first to third vertices, one of the internal angle of the first vertex or the internal angle of the second vertex may be 90 degrees or more. it can.
Further, the near-field light generating method of the present invention uses the near-field exposure mask according to any one of the above, and an electric field concentration, surface plasmon polariton interference, and plasma oscillation in an asymmetric system in the cross-sectional shape. By generating at least one of the above, strong near-field light is generated in the vicinity of a sharp vertex in the asymmetric sectional shape of the mask.
Further, the near-field light generating method of the present invention includes an effective propagation distance of the surface plasmon polariton propagating from one side in the asymmetric system in the interference of the surface plasmon polariton, and the other opposite direction. The difference is that the difference from the effective propagation distance of the surface plasmon polariton propagating from the side is an odd multiple of approximately half the wavelength of the surface plasmon polariton.
The near-field light generation method of the present invention is characterized in that strong near-field light is generated in the vicinity of a sharp apex in the asymmetric cross-sectional shape in the plasma vibration.
Further, the method for producing a near-field exposure mask of the present invention includes one or more metal microstructures having a size equal to or smaller than the wavelength of light used for exposure formed on a mask base material, or a light shielding layer on the mask base material. When producing a near-field exposure mask having a pattern portion with a plurality of micro openings having a size equal to or smaller than the wavelength of light used for exposure formed in the metal fine structure or the light shielding layer between the micro openings It has a step of forming a cross section in a direction perpendicular to the surface of the mask into an asymmetric shape.
Further, in the method for producing a near-field exposure mask of the present invention, the step of forming the asymmetric shape includes a step of forming a metal light shielding layer, a step of forming an etching mask layer, and the etching mask layer. And etching the metal light-shielding layer at an angle with respect to the normal to the surface of the etching mask layer. Further, in the method for producing a near-field exposure mask of the present invention, the step of forming the asymmetric shape includes a step of forming a metal light shielding layer, a step of forming an etching mask layer, and the etching mask layer. A step in which the cross-sectional shape of the etching mask layer cut along a plane including the normal line of the metal light-shielding surface is processed into a shape having no line symmetry axis parallel to the normal line, and the metal light-shielding layer is formed using the etching mask. And a step of etching.
Further, in the method for producing a near-field exposure mask of the present invention, the step of forming the asymmetric shape includes a step of forming a metal light shielding film, a step of forming an etching mask layer, and generating near-field light. A step of patterning the etching mask layer by irradiating the exposure mask to be exposed with exposure light at an angle with the normal line of the exposure mask.
Further, in the method for producing a near-field exposure mask according to the present invention, the step of forming the asymmetric shape includes a step of forming a metal light-shielding layer, and a rotational symmetry axis parallel to the normal line of the surface of the metal light-shielding layer. And a step of processing the metal light-shielding layer using a beam having an intensity distribution that is not included.
Further, in the method for producing a near-field exposure mask according to the present invention, the step of forming the asymmetric shape includes a step of forming a metal light shielding layer and a beam having an angle with respect to a normal line of the surface of the metal light shielding layer. And a step of processing the metal light shielding layer.
A near-field exposure apparatus according to the present invention includes any one of the above-described near-field exposure masks, an object to be exposed, and an exposure light source.
Moreover, the near-field exposure method of the present invention uses the near-field exposure mask described above to irradiate the near-field exposure mask with exposure light, or as described above. Using a near-field light generation method, strong near-field light is generated in the vicinity of a sharp apex in the asymmetric cross-sectional shape of the mask, and the object to be exposed is exposed.
The microelement manufacturing method of the present invention is characterized in that microelements are formed using the above-described near-field exposure apparatus or near-field exposure method.

  According to the present invention, a near-field exposure mask capable of generating near-field light with high efficiency and capable of generating strong near-field light at a desired position, a method for generating near-field light, A method for manufacturing a near-field exposure mask, a near-field exposure apparatus, a near-field exposure method, and a method for manufacturing a microelement can be realized, and the lateral spread of the near-field light generation region can be suppressed to a low level. Therefore, high-resolution exposure can be performed in a short time.

Next, a method for generating near-field light in the embodiment of the present invention will be described. Here, in order to generate near-field light at a desired position and further increase the near-field light intensity, mainly <1> electric field concentration, <2> surface plasmon polariton interference, and <3> free in metal Three phenomena of electron plasma oscillation were used.
By generating these in a system that is “asymmetric” with respect to the incident light, strong near-field light is generated at the desired location, particularly near the top of the metal microstructure or the exit surface of the minute aperture. This is based on the knowledge found for the first time as a result of intensive studies by the present inventors.

The principle of increasing the near-field light intensity at a desired position near the surface of the fine structure when the above phenomenon occurs in the fine structure or the minute opening will be described below. First, the above phenomena <1> to <3> will be described.
The electric field concentration of <1> above is a phenomenon in which, when a substance is placed in an electric field, the electric field concentrates on that part when the shape of the substance has corners such as vertices. Since it is a known phenomenon, details are omitted. Note that this effect increases as the apex protrudes with respect to the electric field direction and the tip of the apex is sharp, and conversely, even if the apex protrudes in a direction perpendicular to the electric field direction, the electric field concentration effect hardly occurs. is required.

Next, the interference of the surface plasmon polariton of <2> will be described.
Surface plasmon polariton (SPP) is a charge density wave generated at the interface between a metal and a dielectric. SPP cannot be coupled with ordinary propagating light, but can be coupled with evanescent waves or with propagating light using a scatterer.
Here, a description will be given with reference to FIG.
This figure is an example of the present invention. In FIG. 1, it is assumed that a fine structure made of metal is formed on the surface of a base material. Light enters this fine structure. The polarization of this light is as shown in the figure. Here, the polarization direction is the direction of the photoelectric field vector. The metal microstructure in the figure forms a metal-air interface with the surrounding air. When light is incident on the metal microstructure, vertices A and B function as scatterers, and SPP is generated on the surface of the metal microstructure.

  Here, the phase of this SPP will be described. The direction of the photoelectric field at a certain time is indicated by E in the figure. At this time, the photoelectric field E applied to the vertices A and B is applied to the vertex A toward the inside of the metal microstructure, and conversely to the vertex B toward the outside of the metal microstructure. Applied. In other words, the photoelectric fields applied to the vertices A and B at the same time have opposite directions with respect to the surface of the metal microstructure, which is equivalent to the application of antiphase electric fields to the vertices A and B. It is. Therefore, the SPP generated from the apexes A and B by this applied electric field is in opposite phase.

  Next, consider that these SPPs propagate to the vertex C. The SPP propagated from the vertex A to the vertex C and the SPP propagated from the vertex B to the vertex C interfere with each other at the vertex C. In order to generate near-field light at the vertex C and its vicinity, it is necessary for the vertex C to interfere with each other in the same phase. For this purpose, the difference between the propagation distance a from the vertex A to the vertex C and the propagation distance b from the vertex B to the vertex C needs to be an odd multiple of a half wavelength of the SPP wavelength. On the contrary, strong near-field light can be generated in the vicinity of the vertex C by forming the metal microstructure in the shape as described above. Here, the propagation distances a and b are not determined only by the geometric shape of the metal microstructure, but are effective propagation distances taking into consideration the effective refractive index at the interface. Therefore, for example, when the metal microstructures are arranged in an array and the interval is very small compared to the wavelength of light (FIG. 2 (a)), or the surface of the metal microstructure has another high refractive index. When a dielectric or the like is formed, the effective refractive index at the interface changes. Therefore, it is necessary to determine the propagation distance in consideration of these points.

Finally, plasma oscillation of free electrons in the metal <3> will be described.
When the metal is irradiated with light, free electrons near the surface of the metal vibrate and follow the vibration of the photoelectric field. As a result, the photoelectric field is canceled at a depth in the vicinity of the very surface of the metal (about 10 nm) and does not penetrate into the metal. However, when the size of the metal itself becomes several tens of nm or less, almost all free electrons in the metal are affected by the photoelectric field due to the penetration of the photoelectric field, and oscillate at a frequency substantially equal to the photoelectric field. . If the metal microstructure and the incident light resonate, the entire free electrons in the metal will cause plasma oscillation.

This results in a charge density distribution within the metal microstructure. This electric charge density distribution generates an electric field in the vicinity of the metal microstructure, and this electric field becomes near-field light. This charge density distribution varies depending on the shape, dielectric constant, light frequency, etc. of the metal microstructure. However, as a tendency, since free electrons in the metal receive a force parallel to the incident photoelectric field vector, near-field light is generated in the vicinity of the apex of the metal microstructure that protrudes in the oscillation direction of the photoelectric field. For example, in the situation as shown in FIG. 1B, strong near-field light is generated at vertex A and vertex C.
The surface plasmon polariton interference of <2> and the plasma oscillation of <3> can occur simultaneously, but the interference of the surface plasmon polariton of <2> is relatively large (diameter of about several microns to 100 nm). The above-mentioned <3> plasma vibration is remarkable in relatively small particles (diameter of about several tens of nm to several nm). Further, the electric field concentration effect <1> occurs regardless of the size of the metal microstructure. It is desirable to generate stronger near-field light due to the synergistic effect of these phenomena.

Here, near-field light is generated using <1> to <3> described above, but what is important in using these is "system asymmetry". For example, when near-field light is generated in the vicinity of the vertex C in FIG. 1A due to the interference of the surface plasmon polariton in <2> above, it is necessary to make a predetermined difference between the propagation distances a and b of the SPP. The metal microstructure and the surrounding environment need to be asymmetric with respect to incident light.
Even in the case of <3> plasma vibration, if the metal microstructure is symmetrical with respect to the incident light in FIG. 1B, almost no near-field light is generated in the vicinity of the vertex C. In order to generate near-field light in the vicinity of the vertex C, the metal microstructure needs to be asymmetrical with respect to the incident light as much as possible. More preferably, in FIG. 1B, the vertex C protrudes further to the right in the drawing than the vertex B.

The above phenomena <1> to <3> occur not only in the metal microstructure but also in the minute aperture. For example, in the system as shown in FIG. 2B, near-field light can be selectively generated in the vicinity of the vertices B and D for the reasons described above. If the system is symmetrical as shown in FIG. 2 (c), near-field light is generated in the vicinity of vertices A to D in the same manner, and selective to the vicinity of the desired vertex. It will not be possible to generate near-field light. In addition, when the vicinity of a sharp vertex cannot be selected as a position for generating near-field light, the generated near-field light intensity is weakened. In other words, in order to generate strong near-field light at a desired position (especially near the top of the exit surface side of the metal microstructure or microscopic aperture), the effects of 1) to 3) can be expressed in the “asymmetric system”. It becomes important.
Then, the lateral spread of the near-field light generation region generated at a desired location by the above-described method is very narrow. For example, by using this to expose a photoresist, a fine pattern latent image can be obtained as desired. Can be formed at the position.

Examples of the present invention will be described below.
[Example 1]
FIG. 3 is a process diagram for explaining a method for producing a near-field exposure mask in Example 1 of the present invention.
First, a substrate 301 that is a Si wafer with a (100) plane is prepared. A silicon nitride film having a thickness of 500 nm is formed on the surface of the substrate to form a base material 302 (FIG. 3A).
Next, the back etch hole 303 is patterned in the base material on the emission surface side by photolithography. Further, a 50 nm thick Cr film is formed as a light shielding metal layer 304 on the base material on the exit surface side (FIG. 3B).

Next, after forming an etching mask layer on the light-shielding metal layer, the etching mask layer is patterned into a slit array using an EB drawing apparatus and a dry etching apparatus, and then a fine pattern 305 is formed to remove the etching mask layer. (FIG. 3C). However, the patterning method is not limited to this. These methods may be used singly or in combination to produce a desired shape including lift-off and other methods. The etching mask layer is preferably SiO ₂ , SiN, photoresist or the like, but is not limited thereto. The fine pattern is formed so that the width of the light shielding metal layer is about 110 nm.

Next, SiO ₂ is sputter-deposited as the auxiliary layer 306 on the emission surface side (FIG. 3D). Further, the surface of the auxiliary layer is polished to be flush with the light-shielding metal layer 304, and then 20 nm of Al is formed as the metal layer 307, and is patterned so as to cover the opening of the fine pattern 305. And it etches diagonally using an ICP-RIE apparatus (FIG.3 (e)). However, this processing is not limited to the technique using the ICP-RIE apparatus.
Next, the metal layer 307 is removed, and the auxiliary layer 306 is further removed. Then, after depositing 50 nm of silicon nitride as the high refractive index layer 308, patterning is performed using an EB drawing apparatus or the like to form silicon nitride on the fine pattern 305. Next, anisotropic etching is performed on the KOH aqueous solution, and the base material and the light-shielding metal layer are made into a membrane to complete the mask (FIG. 3F).

In this embodiment, the mask is made into a membrane, but if the substrate 301 is made of a material that is transparent to the exposure wavelength, the mask is not necessarily made into a membrane.
Here, light is incident on the near-field light generating mask. The incident light is light from a mercury lamp (wavelength 436 nm). SPP (wavelength is approximately 400 nm) is generated on the surface of the light shielding metal layer. With this mask configuration, the propagation distance of the SPP from the first vertex on the entrance surface side of the mask to the vertex on the exit surface side and the second vertex on the entrance surface side of the mask to the third vertex on the exit surface side The difference from the propagation distance of SPP is 100 nm, and considering the effective refractive index, the difference in propagation distance is 200 nm, which is substantially half of the SPP wavelength, so near-field light is generated near the third vertex.
The near-field light exposure mask of this embodiment can efficiently convert the energy of incident light into near-field light. In addition, the region where strong near-field light is generated can be reduced by the shape of the light shielding metal layer.
In addition, the presence of the high refractive index layer makes it possible to easily cause a difference in the desired SPP propagation distance on the surface of the light shielding metal layer.

In this embodiment, the cross-sectional shape of the light shielding metal layer is substantially triangular, but this shape is a preferable shape because it can be manufactured relatively easily. Further, it is more preferable that one of the apexes on the incident surface side of the triangle is formed at an obtuse angle because the near-field light intensity generated is increased. However, in the present invention, the cross-sectional shape of the light shielding metal layer is not limited to these shapes, and for example, the above process may be a parallelogram formed in the process of FIG. In the case of the parallelogram, the strength of the mask surface can be maintained because the exit surface side of the mask is relatively planar. Furthermore, an asymmetric polygon or a shape with rounded corners may be used. In this shape, for example, as the number of vertexes of the polygon increases, the propagation loss of the SPP per vertex is reduced, so that the SPP can be propagated to the output side vertex with high efficiency.
In addition, if the SPP phase difference can be adjusted to a desired value only by the cross-sectional shape of the light-shielding metal layer even without the high refractive index layer, the near-field light exposure mask of the present invention can be produced by a simpler process. Can do.
In this embodiment, the metal microstructure is formed. However, it is also possible to form the minute opening into a desired shape by using a substantially similar method.

[Example 2]
FIG. 4 is a process diagram for explaining a method for producing a near-field exposure mask in Embodiment 2 of the present invention.
First, a substrate 401, which is a Si wafer with a (100) plane, is prepared. A silicon nitride film having a thickness of 500 nm is formed on the surface of the substrate to form a base material 402 (FIG. 4a).
Next, the back etch hole 403 is patterned in the base material on the incident surface side by photolithography. Further, Cr having a film thickness of 50 nm is formed as a light shielding metal layer 404 on the base material on the emission surface side (FIG. 4b).

Next, the light shielding metal layer is patterned using the focused ion beam 406. At this time, the shape of the light shielding metal layer is made asymmetric by irradiating the substrate with the focused ion beam 406 obliquely. Next, anisotropic etching is performed with a KOH aqueous solution to form a base material and a light shielding metal layer as a membrane (FIG. 4c).
Here, light is incident on the near-field light exposure mask. The incident light is a mercury lamp (wavelength 436 nm), and the grating pitch is made approximately 100 nm.
Plasma vibration due to metal free electrons occurs in the light shielding metal layer. As a result, near-field light is generated in the vicinity of the exit surface side apex of the light shielding metal layer. The size of the generation area is limited to the apex of the light-shielding metal layer and the vicinity thereof.

The near-field light exposure mask of this embodiment can efficiently convert the energy of incident light into near-field light. In addition, the region where strong near-field light is generated can be reduced by the shape of the light shielding metal layer.
In this embodiment, the cross-sectional shape of the light-shielding metal layer is an asymmetric quadrilateral with different radii of curvature at the two vertices on the exit side, but this is not restrictive, and the corners of a parallelogram or asymmetric polygon are rounded. It may be a shape. The size is preferably about 100 nm or less on one side as in the present embodiment.
Further, if the intensity distribution of the focused ion beam is asymmetrical with respect to the traveling direction, the light shielding metal layer may be irradiated vertically instead of obliquely.
In this embodiment, the light shielding metal layer is formed. However, it is possible to form the minute opening into a desired shape by using substantially the same means.

[Example 3]
FIG. 6 is a process diagram for explaining a method for producing a near-field exposure mask in Example 3 of the present invention.
First, a substrate 601 that is a Si wafer having a (100) plane is prepared. A silicon nitride film having a thickness of 500 nm is formed on the surface of the substrate to form a base material 602 (FIG. 6a).
Next, a back etch hole 603 is patterned in the base material on the incident surface side by photolithography. Further, Cr having a film thickness of 50 nm is formed as a light shielding metal layer 604 on the base material on the exit surface side (FIG. 6b).

Next, a photoresist 605 is applied to the light shielding metal layer 604 and patterned (FIG. 6c). At this time, it is preferable that the photoresist is exposed obliquely with respect to the substrate, and is adjusted to the angle at which the next dry etching is performed obliquely. Next, the substrate is dry-etched using an ICP-RIE apparatus or the like. At this time, the shape of the metal light-shielding layer is made asymmetric by dry-etching with respect to the substrate. Next, anisotropic etching is performed with a KOH aqueous solution to form a base material and a light shielding metal layer as a membrane (FIG. 6d).
Here, light is incident on the near-field light exposure mask. The incident light is a mercury lamp (wavelength 436 nm). Plasma vibration due to metal free electrons occurs in the light shielding metal. As shown in the figure, the light shielding metal is formed in a parallelogram, and as a result, a stronger near-field light is generated in the vicinity of the apex of the acute angle among the vertices on the exit surface side of the light shielding metal layer. The size of the generation area is limited to the apex of the light-shielding metal layer and the vicinity thereof.

The near-field light exposure mask of this embodiment can efficiently convert the energy of incident light into near-field light. In addition, the region where strong near-field light is generated can be reduced by the shape of the light shielding metal layer.
In this embodiment, the cross-sectional shape of the light-shielding metal layer is a parallelogram, but is not limited to this, and may be a shape in which the corners of an asymmetric polygon are rounded.
In this embodiment, the metal light shielding layer is also obliquely dry etched after the etching mask layer is obliquely exposed. However, the present invention is not limited thereto, and the etching may be performed vertically and then dry etching may be performed. Even in this case, since the distribution of the thickness of the photoresist is caused by the oblique exposure, the light shielding metal layer can be formed asymmetrically even if this is vertically etched. For this oblique exposure, for example, multiple exposure may be used, or an asymmetric near-field distribution is generated by an exposure method in which the near-field exposure mask is obliquely illuminated, and this is used to asymmetrically expose and pattern the etching mask layer. May be.

[Example 4]
FIG. 5 shows a configuration in which the near-field light exposure mask of the present invention in Example 4 of the present invention is applied to an exposure apparatus.
The near field light generated from the near field light exposure mask 501 is irradiated onto the resist 502 on the substrate, and exposure (latent image formation) is performed on the resist 502. Here, as the light source 503 for exposure, a light source that generates light having a wavelength for exposing the resist 502 is used.
An alignment / exposure control computer 504 is used to align the resist 502 with respect to the near-field light exposure mask 501.
As described above, according to the present embodiment in which the near-field light exposure mask of the present invention is applied to an exposure apparatus, highly efficient near-field light can be generated, and therefore, exposure can be performed in a short time. In addition, since the near-field light generation region is a minute range, high-resolution exposure can be performed.

[Example 5]
FIG. 7 is a diagram for explaining a method for manufacturing a microelement in Example 5 of the present invention.

In this example, an antireflection structural element as shown in FIG. 7 was produced by a near-field exposure apparatus (or exposure method) using the near-field light exposure mask of the present invention.
That is, the near-field exposure apparatus (or exposure method) using the near-field light exposure mask of the present invention is suitable for manufacturing an optical element having a sub-wavelength structure (= SWS). Therefore, an example of a specific device is an antireflection structural element as shown in FIG.
The antireflection structural element shown in FIG. 7 is composed of a two-dimensional array of quartz conical structures 702 formed on a quartz substrate 701. Here, if the pitch of the quartz conical structure 702 is made smaller than the wavelength of light incident on the substrate, this structure has a non-reflective function for incident light. Further, as in the first example, a defect may be introduced into a part of the quartz conical structure as necessary to partially have a reflection (scattering) function.

The manufacturing method of such an antireflection structural element is as follows.
First, a negative photoresist coating → exposure → development process is performed on the quartz substrate using the above-described exposure apparatus, and the resist is patterned into a predetermined two-dimensional dot array shape.
Next, by using this two-dimensional dot array-shaped photoresist pattern as a mask, quartz is etched to form a conical structure with a sharp tip and wide skirt as shown in FIG.
According to this example, compared with the structure of the above-described element manufactured using a conventional self-organizing method, the structure to be manufactured improves the regularity of the period and size, so that the device performance is greatly improved. It becomes possible to make it.

Schematic for demonstrating embodiment of this invention. Schematic for demonstrating embodiment of this invention. Process drawing for demonstrating the manufacturing method of the mask for near-field exposure in Example 1 of this invention. Process drawing for demonstrating the preparation methods of the near-field exposure mask in Example 2 of this invention. The figure which shows the structure which applied the near-field light exposure mask of this invention in Example 4 of this invention to the exposure apparatus. Process drawing for demonstrating the manufacturing method of the mask for near-field exposure in Example 3 of this invention. 10A and 10B illustrate a method for manufacturing a microelement in Example 5 of the present invention.

Explanation of symbols

301: Substrate 302: Base material 303: Back etch hole 304: Light shielding metal layer 305: Fine pattern 306: Auxiliary layer 307: Metal layer 308: High refractive index layer 401: Substrate 402: Base material 403: Back etch hole 404: Light shielding Metal layer 405: Fine pattern 406: Focused ion beam 501: Near-field light exposure mask 502: Resist 503: Light source 504: Positioning / exposure control computer 505: Light 601: Substrate 602: Base material 603: Back etch hole 604: Light shielding Metal layer 605: Photoresist 606: Fine pattern 701: Quartz substrate 702: Quartz cone structure

Claims (10)

A near-field exposure mask having a pattern formed by a metal microstructure having a size equal to or smaller than the wavelength of light used for exposure, which is configured by a light shielding layer formed on a mask base material, or a minute opening provided in the light shielding layer Because
At least one of a cross section in a direction perpendicular to the mask surface of the metal microstructure or a cross section in a direction perpendicular to the mask surface of the minute opening is asymmetric with respect to an arbitrary symmetry axis perpendicular to the mask surface. A near-field exposure mask having a unique cross-sectional shape. The mask includes a configuration in which light used for the exposure is incident from the first surface side of the mask and a photoelectric field is generated from the second surface side,
The near-field exposure mask according to claim 1, wherein at least one sharp apex is provided in the vicinity of the second surface side in the asymmetric cross-sectional shape of the mask.   The near field exposure mask according to claim 1, wherein the asymmetric cross-sectional shape is a substantially triangular shape, a substantially rectangular shape, or a substantially polygonal shape including a substantially parallelogram.   4. The near-field exposure mask according to claim 1, wherein at least one of electric field concentration, surface plasmon polariton interference, and plasma oscillation is generated in an asymmetric system in the cross-sectional shape. By generating strong near-field light in the vicinity of a sharp apex in the asymmetric cross-sectional shape of the mask.   Surface plasmon polariton interference is the difference between the effective propagation distance of the surface plasmon polariton propagating from one side in the asymmetric system and the effective propagation distance of the surface plasmon polariton propagating from the other side in the opposite direction. 5. The method of generating near-field light according to claim 4, wherein the difference is generated so as to be an odd multiple of approximately half the wavelength of the surface plasmon polariton. 5. The method of generating near-field light according to claim 4, wherein strong near-field light is generated in the vicinity of a sharp vertex in the asymmetric cross-sectional shape by the plasma vibration. In the method for producing a near-field exposure mask,
One or more metal microstructures having a size smaller than the wavelength of light used for exposure formed on the mask base material, or a plurality of sizes smaller than the wavelength of light used for exposure formed on the light shielding layer on the mask base material When producing a mask for near-field exposure having a pattern portion by a minute opening of
Producing a near-field exposure mask comprising a step of forming a cross section in a direction perpendicular to the surface of the mask in the light shielding layer between the metal microstructures or the micro openings in an asymmetric shape Method.   A near-field exposure apparatus comprising the near-field exposure mask according to claim 1, an object to be exposed, and an exposure light source.   The near-field exposure mask according to any one of claims 1 to 3 is used to irradiate the near-field exposure mask with exposure light, or any one of claims 4 to 6. A near-field light generating method according to claim 1, wherein strong near-field light is generated in the vicinity of a sharp vertex in the asymmetric cross-sectional shape of the mask to expose an object to be exposed. Field exposure method.   A method for producing a microelement, wherein the microelement is produced by using the near-field exposure apparatus according to claim 8 or the near-field exposure method according to claim 9.

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