TWI646598B - Microscopic three-dimensional structure forming method and microscopic three-dimensional structure - Google Patents

Abstract

An object of the present invention is to form a fine three-dimensional structure having a smooth side surface that is etched in the vertical direction at a low cost, quickly, and faithfully. As a solution, a microscopic structure forming method is provided, comprising: a step (1) of forming a resist pattern drawn by maskless exposure on a substrate; an isotropic etching step (2A), Forming a recess on the substrate by isotropic etching; a plasma deposition step (2B) of depositing the protective film on the inner wall of the recess and the resist pattern; and removing the step (2C) by anisotropic etching a protective film for removing the bottom surface of the recess; and a step (2) of sequentially performing an isotropic etching step (2A), a plasma deposition step (2B), and a removing step (2C), thereby forming a fine layer on the substrate Concave.

Description

Microscopic three-dimensional structure forming method and microscopic three-dimensional structure

The present invention relates to a method for forming a fine three-dimensional structure and a fine three-dimensional structure.

It is necessary to accurately form a microscopic three-dimensional structure as a semiconductor three-dimensional package, or an optical waveguide, a micro flow path, a microreactor, a nanoimprint mold, etc., and it is being studied to use a semiconductor precision processing process, that is, lithography ( Lithography) and etching method of forming a fine three-dimensional structure.

For the lithography for forming a fine three-dimensional structure, it is required to obtain an exposure having a high resolution of a resist having a uniform film thickness. When the resolution of the exposure is low, the vicinity of the boundary of the resist pattern formed after development is blurred, and the resist is thinned, which is a state in which the resist is tailed. In Fig. 15 (a), the trailing resist 401 formed on the ruthenium substrate W is shown. In the etching step, the resist is also slightly etched together with the ruthenium substrate. Therefore, if the resist is etched as a mask, the hem portion of the resist gradually disappears as the etching progresses. The etching of the portion where the resist of the ruthenium substrate disappears (Fig. 15 (b)) finally causes the ruthenium substrate to be etched into a trapezoidal shape (Fig. 15 (c)). Therefore, for a lithography for forming a fine three-dimensional structure, a resist having a uniform film thickness is required so that the etching proceeds in the vertical direction, and the resolution of exposure is required to be high.

Typically, masks are used during exposure, but masks are very expensive and the fabrication of the mask itself can be time consuming. Therefore, an exposure method in which computer image data is directly printed without mask exposure without using a mask has been proposed (refer to Patent Document 1). Fig. 16 is a schematic view showing the light intensity in the exposure point without the mask exposure, and the film thickness after the pattern development after the maskless exposure. Since the maskless exposure is performed by condensing the light from the light source by the reduction projection lens, the light intensity at the center portion of the exposure point is strong, and the light intensity at the peripheral portion is weak. Therefore, the unmasked exposure causes the resist to be formed after development to tail. Since the maskless exposure cannot perform high-resolution exposure and it is difficult to perform etching in the vertical direction, it is considered to be unsuitable for forming a fine three-dimensional structure. Further, the maskless exposure is mainly used for a printed circuit board having a pattern width of about 100 μm and requiring no high resolution, and is hardly used for forming a fine pattern.

Further, in order to form a fine three-dimensional structure by etching, it is necessary to faithfully polish the resist pattern after development and smoothly perform etching in the vertical direction. As described above, even if a high-resolution exposure is performed and a resist having a uniform film thickness is etched as a mask, the resist is side-etched little by little. When etching is time-etched, the thickness of the resist is narrowed by side etching as the etching progresses. Therefore, the substrate is etched in a slightly inclined direction, and etching cannot be performed accurately in the vertical direction.

Here, as a deep etching technique, an etching method called a BOSCH process is proposed in Patent Document 2, and the deep etching technique is used to manufacture a resolution of a micro electro mechanical system (MEMS) or the like. A device having a three-dimensional structure of up to about 10 μm. Fig. 17 (a) to Fig. 17 (d) show the steps of the Bosch process. The Bosch process is a method of repeatedly performing a process in which three steps are one cycle, and the three steps refer to a step of isotropic etching the tantalum substrate W having the resist 401 on the surface (FIG. 17(a) a step of depositing the protective film 403 on the side surface and the bottom surface of the recess 402 formed by etching (FIG. 17(b)), and removing the protective film on the bottom surface of the recess by anisotropic etching (FIG. 17 (FIG. 17) c)). For the Bosch process, in the isotropic etching, the side surface of the recess protected by the protective film is not etched, and isotropic etching is performed starting from the bottom surface of the recess in which the protective film has been removed. By performing the isotropic etching on the bottom surface of the recesses in reverse, the etching is performed only in the longitudinal direction, so that a hole having a depth of 100 μm or more can be formed in the vertical direction (Fig. 17 (d)).

However, for the Bosch process, in the isotropic etching step, the etching is performed at a uniform speed in all directions, and therefore, the substrate is planed into a spherical shape. Therefore, irregularities which are called a sector-shaped structure (Scallop pattern 404) in synchronization with the etching cycle are formed on the side surface of the hole, and it is impossible to manufacture a hole having a smooth side surface. If the time taken for one cycle of the Bosch process (hereinafter also referred to as the cycle time) is shortened, the sector-shaped distortion structure can be reduced, but the exhaust time of the etching gas and the protective film forming gas is at least about 4 seconds, respectively. The cycle time is more than 8 seconds. If another gas is introduced before one gas is completely discharged, the cycle time can be shortened, but a sufficient protective film is not formed on the side surface of the hole, and the side surface is etched by the isotropic etching step, so that it cannot be formed in the vertical direction. hole.

That is, in the normal Bosch process for sufficiently replacing the gas, the cycle time cannot be made shorter than 8 seconds, and in the etching period of 4 seconds including the exhaust gas, a sector-shaped structure is formed, and therefore, it is inevitable that Sector-shaped distortion structure. Further, when the hole is formed by the Bosch process, in order to shorten the processing time, it is necessary to reduce the number of cycles required to form the hole, and to set the isotropic etching so as to perform etching greatly. Therefore, the usual Bosch process forms a hole having a sector-shaped distortion-like structural depth of 500 nm or more formed on the side.

In order to obtain a hole having a smooth side surface by using a Bosch process, as described in Patent Document 3, a flattening process such as dry etching for flattening the sector distortion structure is required. Oxide film formation, neutral particle beam etching, and the like are also used in the planarization process, but either method causes a change in the size of the pores. Further, for a typical Bosch process, the mask undercut is as large as 500 nm or more. That is, in the etching of the Bosch process, since the undercut portion of the mask is large and the size of the hole changes due to the flattening process, it is difficult to form the designed hole of a desired size.

As described above, the usual etching cannot be performed by deep etching in the vertical direction, resulting in a trapezoidal shape that is inclined to the side. Further, although the Bosch process can perform deep etching in the vertical direction, a sector-shaped structure is formed, so that a smooth side surface cannot be obtained, and it is difficult to form a hole that is faithful to the design size. That is, it is very difficult to form a fine three-dimensional structure having a smooth side surface etched in the vertical direction by etching, faithfully designing. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei.

An object of the present invention is to form a fine three-dimensional structure having a smooth side surface that is etched in the vertical direction at a low cost, quickly, and faithfully.

A method for forming a fine three-dimensional structure, comprising: step (1) of forming a resist pattern drawn by maskless exposure on a substrate; and an isotropic etching step (2A) Forming a recess on the substrate by isotropic etching; a plasma deposition step (2B) of depositing a protective film on the inner wall of the recess and the resist pattern; removing step (2C) by An anisotropic etching to remove the protective film on the bottom surface of the recess; and a step (2) of sequentially performing an isotropic etching step (2A), a plasma deposition step (2B), and a removing step (2C), Thereby, fine recesses are formed in the substrate. 2. The method of forming a microstructure according to 1. wherein the maskless exposure is multiple exposure.

3. The method of forming a fine three-dimensional structure according to the above aspect, wherein when the widths of the 10% depth position, the 50% depth position, and the 90% depth position of the fine recess are set to W10, W50, and W90, respectively. The variation coefficients (W10 to W90) of W10, W50, and W90 are 5% or less.

4. The method of forming a fine three-dimensional structure according to any one of the above aspects, wherein the period P of the sector-shaped distortion-like structure on the side surface of the fine concave portion is 100 nm or less.

5. The method of forming a fine three-dimensional structure according to any one of the above aspects, wherein the depth D of the sector-shaped structural structure on the side surface of the fine concave portion is 30 nm or less.

6. The method of forming a fine solid structure according to any one of 1 to 5, wherein the substrate has a diameter of 0.5 inch.

7. The method of forming a fine three-dimensional structure according to any one of the above aspects, wherein the cycle time is 0.5 seconds or more and 6 seconds or less.

8. The method of forming a fine three-dimensional structure according to the above aspect, wherein the coefficient of variation (W10 to W90) is 3.5% or less.

The method of forming a fine three-dimensional structure according to any one of the above aspects, wherein the depth D of the sector-shaped distortion-like structure is 12 nm or less.

A fine three-dimensional structure comprising: a fine concave portion having a depth of 20 μm or less and a width of 3 μm or more on a substrate, wherein a 10% depth position, a 50% depth position, and a 90% depth position of the fine concave portion are When the width is set to W10, W50, and W90, the variation coefficients (W10 to W90) of W10, W50, and W90 are 5% or less.

11. The fine three-dimensional structure according to 10., wherein a period P of the sector-shaped distorted structure on the side surface of the fine concave portion is 100 nm or less. 12. The fine three-dimensional structure according to 10. or 11, wherein the sector-distortion structure has a depth D of 30 nm or less. The fine three-dimensional structure according to any one of the items 10 to 12, comprising: a fine convex portion adjacent to the fine concave portion; and a resist covering a top portion of the fine convex portion The film thickness of the end portion of the resist is thinner than the film thickness at the center portion. 14. The fine three-dimensional structure according to 13. wherein the width of the undercut of the upper end portion of the fine convex portion is 30 nm or less. The fine three-dimensional structure according to any one of 10 to 14, wherein the substrate has a diameter of 0.5 inch. 16. The fine three-dimensional structure according to 15. wherein the coefficient of variation (W10 to W90) is 3.5% or less. 17. The fine three-dimensional structure according to 15. or 16. wherein the sector-distortion configuration has a depth D of 12 nm or less.

The fine three-dimensional structure forming method of the present invention utilizes a maskless exposure to trace a resist pattern, and thus, an expensive mask is not required. The maskless exposure can be easily drawn using a computer. Therefore, according to the microscopic structure forming method of the present invention, it is possible to manufacture a fine three-dimensional structure in a small batch, which is suitable for a small variety of production, or order made production, On demand (on demand) production. Moreover, by performing multiple exposures, a smooth pattern can be drawn in the horizontal direction.

The microscopic structure forming method of the present invention is etched by a so-called Bosch process. The Bosch process is less susceptible to etching by about 10 times compared to conventional etching. The thickness near the boundary of the resist pattern drawn by the maskless exposure is thinner than the thickness of the central portion of the pattern, but by using the Bosch process, the initial shape of the resist after the maskless exposure is in the etching step. There is almost no change, including the trailing part. Therefore, even if the film thickness of the resist is not uniform, it is possible to etch along the vertical direction along the drawn resist pattern, and it is possible to form fine recesses in which the width in the depth direction hardly changes. Further, by performing the isotropic etching in the Bosch process in detail, it is possible to form a fine recess having a small depth of the sector-shaped structure and having a smooth side surface.

The fine three-dimensional structure forming method of the present invention can form a fine concave portion having a smooth side surface without performing an additional planarization step. Further, the error between the width of the actually obtained fine concave portion and the design size is extremely small, and a fine three-dimensional structure that is substantially faithful to the pattern drawn by the unmasked exposure can be formed.

The use of a half-inch ruthenium substrate reduces the capacity of the chamber for generating plasma and uses an exhaust device having sufficient exhaust capacity for the chamber capacity, whereby the processing in the Bosch process can be replaced at high speed. gas. Therefore, the processing gas can be sufficiently replaced in a cycle time of 6 seconds or less that has not been possible in the past, and the Bosch process can be repeatedly performed. By performing a Bosch process with a cycle time of 6 seconds or less, it is possible to form fine recesses having more vertical and smoother sides. Further, since the cycle time is short, even if the Bosch process is repeatedly performed for several hundred cycles, the processing time of the fine three-dimensional structure is short and the productivity is excellent.

The fine three-dimensional structure of the present invention is superior in verticality and smoothness of the side surface as compared with a conventionally known fine three-dimensional structure having a fine concave portion having a depth of 20 μm or less. The unevenness of the side surface is small with respect to the wavelength of light, and the perpendicularity of each surface is also excellent. Therefore, the attenuation at the time of light reflection is reduced, and it can be suitably used as an optical waveguide. The error between the design size and the design size is small, and the desired shape can be formed, and therefore, it can be suitably used as a diffraction grating or a hologram. Further, since the liquid can be smoothly flowed, it is also suitable as a micro flow path or a microreactor. Further, the fine three-dimensional structure of the present invention having a small depth of the sector-shaped distortion structure on the side surface is less likely to be caught when the structure is transferred and peeled off, and therefore is suitable as a mold for nanoimprinting.

The present invention is a method for forming a fine three-dimensional structure in which a technique for completely different applications in industrial applications is combined, and the technique refers to an unobstructed resolution which is mainly used for patterning of a printed substrate. The Bosch process for forming a sector-shaped distortion-like structure used for the exposure of the cover and the etching in the manufacture of the MEMS.

Hereinafter, the present invention will be described in accordance with the procedures.

(1) Unmasked exposure

First, a resist pattern drawn by maskless exposure is formed on the germanium substrate. It is preferable that the resolution of the maskless exposure is small, and the resolution of the maskless exposure is preferably 0.5 μm or less, more preferably 0.25 μm or less. The width of the resist pattern can be, for example, 0.25 μm or more and 10 μm or less. The shape of the resist pattern is not particularly limited, and for example, any of dots, lines, and faces, or a combination of these, can be drawn. Further, the substrate can be used not only of tantalum, but also tantalum, gallium arsenide, gallium arsenide gallium carbide, tantalum carbide, gallium nitride, sapphire, diamond, or the like.

The maskless exposure can use a method of using a digital micromirror device (Digital Micromirror Device: hereinafter referred to as DMD) having a micromirror of about 10 μm squares arranged vertically and horizontally. Pattern data reflects light from the source. FIG. 1 is a schematic diagram showing an example of digital light processing (DLP) exposure without mask exposure.

The DLP exposure is a method in which light from the light source 201 is reflected by the DMD 202, and light reflected by the DMD is exposed on the ruthenium substrate W via the reduction projection lens 203. In the DLP exposure, the light concentrated by the reduced projection lens is irradiated onto the photoresist film to form a fine pattern. Therefore, the irradiation range of the light is narrow, and scanning for moving the irradiation range is required. Moreover, the shape of the exposure point projected onto the ruthenium substrate is substantially square. Therefore, it is possible to draw a smooth pattern in a direction parallel to the scanning direction, but it is only possible to draw a pattern having a zigzag step in a direction oblique to the scanning direction.

By performing multiple exposures, it is possible to reduce the zigzag step in the plane parallel to the surface of the ruthenium substrate. For example, when the exposure point is 0.5 μm square, the pixel is divided into five and exposed, whereby the step can be set to 0.1 μm. When the resolution of light is 0.3 μm (for example, the i-ray is 0.365 μm), the step of 0.1 μm unit or less below the wavelength of light is weakly drawn, and therefore the step disappears and becomes a smooth pattern.

Here, as described above, the DLP exposure is to illuminate the light concentrated by the reduced projection lens. Therefore, the light intensity at the center portion of the exposure point is strong, the light intensity at the peripheral portion is weak, and the light intensity does not match. Further, when multiple exposure is performed, the number of times of light irradiation in the central portion of the pattern is plural, and the number of times of light irradiation at the boundary portion of the pattern is only one. Fig. 2 is a view showing the light intensity when four exposures are performed by moving the exposure point without mask exposure. Furthermore, in Fig. 2, for simplification, the light intensity in one exposure point is expressed as the same light intensity. Therefore, if multiple exposure is performed, the difference in light intensity between the center portion and the boundary portion of the pattern becomes larger. In other words, the resist pattern drawn by the maskless exposure has a state in which the center portion of the pattern is thick and the pattern boundary portion is thin and trailing regardless of the presence or absence of multiple exposure.

DLP exposure is performed while scanning and performing exposure. Therefore, it is more time consuming to expose the entire surface of the substrate than the mask exposure. For example, when DLP exposure is performed on a wafer having a diameter of 300 mm, about 100 is required. Hours of time. Further, if multiple exposures are divided into five in the vertical and horizontal directions, a time of 2,500 hours (100 × 5 × 5) is required. By reducing the size of the wafer, it is possible to solve the disadvantage of DLP exposure, that is, the exposure of one wafer takes a lot of time. For example, by using a wafer having a half inch size (diameter: 12.5 mm), the wafer area can be made to be about 1700 of a wafer having a diameter of 300 mm. Therefore, it is possible to complete the multiple exposure of one-fifth of five hours requiring 2,500 hours within one hour of one thousandth or less. Further, by realizing the speeding up of the mechanical mechanism of DMD and scanning, it is possible to perform multiple exposure in five minutes in about 40 minutes.

(2) Bosch Process Next, by performing a so-called Bosch process in which the isotropic etching step (2A), the plasma deposition step (2B), and the removal step (2C) are repeated, fine recesses are formed on the tantalum substrate, etc. The etch etching step (2A) forms a recess in the germanium substrate by isotropic etching, and the plasma deposition step (2B) deposits the protective film on the inner wall of the recess and the resist pattern layer, the removing step ( 2C) A protective film for removing the bottom surface of the recess by anisotropic etching (hereinafter, the isotropic etching step (2A) and the removing step (2C) are also referred to as an etching step).

Fig. 3 shows an example of the configuration of a plasma etching apparatus that performs a Bosch process. The plasma etching apparatus 300 includes a cylindrical chamber 301 that generates plasma and performs plasma processing, a gas supply mechanism 302 that supplies a processing gas to the chamber, and a coil 303 that is disposed outside the chamber a coil power supply mechanism 304 that supplies high frequency power to the coil; a base 305 for mounting the 矽 substrate W; a base power supply mechanism 306 that supplies high frequency power to the base; and exhaust Device 307, which vents gas within the chamber.

An etching gas such as SF ₆ , CF ₄ , C ₃ F ₈ , SiF ₄ , or NF _{3 is} used as a processing gas with a protective film such as C ₄ F ₈ or C ₅ F ₈ . The base power supply mechanism 306 switches the on/off of the bias power supplied to the base 305, whereby the anisotropic etching, that is, the removal step (2C) and the isotropic direction can be performed. The etching step (2A) is switched.

In the plasma deposition step (2B) of the microscopic structure forming method of the present invention, not only the protective film is deposited on the inner wall of the recess, but also the protective film is deposited on the resist pattern. Since the protective film is deposited on the resist pattern, the resist is very difficult to be etched as compared with the usual etching. Even if the etching resistance of the resist is a ratio of the resist: etching target material = 1:10, since the protective film is deposited on the resist pattern, the ratio is increased to about 1:100.

The protective film is slightly etched in the etching step, but since the protective film is deposited in the plasma deposition step (2B), the protective film is repaired. The method for forming a fine three-dimensional structure of the present invention forms a resist pattern having a non-uniform film thickness by maskless exposure, but the resist pattern is protected by a protective film in the entire step of the Bosch process, and thus includes a trailing portion. The initial shape of the resist is maintained, and the portion having a small film thickness does not disappear. Since the resist pattern can be maintained and etched, the fine concave portion that faithfully reflects the resist pattern can be formed in the horizontal direction.

Fig. 4 is a schematic view showing a cross section in the depth direction of a fine concave portion formed by the method for forming a fine three-dimensional structure of the present invention. The shape of the fine concave portion in the horizontal direction surface is not particularly limited, and a horizontal direction other than a circular hole, a square hole, a linear shape, a curved concave strip, or the like, or a convex portion such as a cylinder, a quadrangular prism, or a ridge can be used. The substantially entire surface in the plane is set as a fine recess. The fine recessed portion 110 is formed on the meandering substrate W, and includes an opening portion 111, a bottom surface 112, and a side surface 113, and a sector-shaped distorted structure 114 having a period P and a depth D is formed on the side surface 113. The height position of the opening of the fine recess is equal to the surface of the ruthenium substrate before processing. Further, the surface of the ruthenium substrate has a resist pattern 120 which is a resist pattern which is drawn by exposure without a mask. Therefore, the film thickness is not uniform, the central portion is thick, and the boundary portion is thin. Furthermore, in FIG. 4, the sector-shaped distorted structure 114 is more exaggerated than reality.

In the Bosch process, when the width of the fine concave portion is narrowed or the fine concave portion is deepened, there is a tendency that the processing gas hardly enters into the inside of the fine concave portion, and the etching rate is reduced. By setting the width of the fine concave portion to 3 μm or more and the depth to 20 μm or less, it is possible to suppress a decrease in the etching rate. The width of the fine concave portion is preferably 3 μm or more, more preferably 4 μm or more, and still more preferably 5 μm or more. Similarly, the depth of the fine concave portion is preferably 20 μm or less, more preferably 15 μm or less, and still more preferably 12 μm or less.

The fine recess can be etched in the vertical direction by suppressing a decrease in the etching rate in the Bosch process. Specifically, when the 10% depth position, the 50% depth position, and the 90% depth position width of the fine concave portion are respectively W10, W50, and W90, the standard deviation of W10, W50, and W90 can be divided by the average value. The coefficient of variation (W10 to W90) is set to 5% or less. By setting the variation coefficient to 5% or less, for example, when it is an optical waveguide, the parallel reflection of the opposing reflection surfaces is excellent, and it is possible to carry out long-distance transmission while performing total reflection on the interface repeatedly. The coefficient of variation (W10 to W90) is preferably 3.5% or less, more preferably 3% or less, still more preferably 2.7% or less, and most preferably 2% or less. Here, the width of the fine concave portion is a reference to a line connecting a portion which is a portion in which the sector-shaped distortion-like structure is most etched in the horizontal direction. In addition, when the shape of the fine concave portion in the horizontal direction surface is not linear, the first side surface of the fine concave portion in the depth direction cross section and the closest to the first side surface 8 μm or more are the width of the fine concave portion. The distance of the second side at the 10% depth position, the 50% depth position, and the 90% depth position is set to W10, W50, and W90, respectively.

Further, the depth of the depression formed in the primary isotropic etching step (2A) is made shallow, whereby the depth D of the sector-shaped distortion-like structure formed on the side surface of the fine concave portion can be reduced. The depth of the recess formed by the primary isotropic etching step (2A) may vary depending on various conditions such as the frequency or power of the high-frequency power, the pressure or the flow rate of the processing gas, but it is easy to follow the timing of the etching step, especially according to the The base is biased by an isotropic etching step (2A) of bias power. By forming the shallow depressions in a reverse manner, it is possible to form the fine concave portions having the shallow depth D of the sector-shaped structural structure and having smooth sides. Further, the depth of the depression formed in the primary isotropic etching step (2A) corresponds to the period P of the sector-shaped distortion-like structure.

The period P of the depth of the depression formed in the isotropic etching step (2A), that is, the sector-shaped distortion-like structure is preferably 100 nm or less, more preferably 60 nm or less, further preferably 40 nm or less, preferably It is below 20 nm. In order to obtain a smoother side surface, it is preferable that the period P of the sector-shaped distortion-like structure is small, but the time taken to form the fine concave portion becomes long. Therefore, the period P of the sector-shaped distortion-like structure is preferably 1 nm or more, more preferably It is 3 nm or more, and more preferably 5 nm or more.

The depth D of the sector-shaped distortion structure is preferably 30 nm or less, more preferably 20 nm or less, further preferably 12 nm or less, and most preferably 5 nm or less. In addition, when the period P of the sector-shaped distortion-like structure is 40 nm or less, there is a case where the protruding portion of the sector-shaped distortion-like structure is flattened during the Bosch process, and the electron cannot be used in the electrons. The bumps are seen in the microscope image, and in fact, the sector-shaped distortion-like structure disappears. Further, by reducing the sector-shaped structural depth D, the distance between the upper end portion of the side surface of the fine concave portion and the end portion of the resist, that is, the width of the undercut portion of the mask can be made deeper than the depth of the sector-shaped distortion structure. D is the same size.

Further, the shape of the fine recessed portion of the present invention will be described in detail using FIG. 5. Further, for the sake of explanation, FIG. 5 exaggerates the side shape. The upper end of the side surface of the fine concave portion is H0, the depth of the fine concave portion is h0, the height of the side surface is H1, the height of H1 is h1 (=h0/2), and the line passing through H0 and H1 l The intersection point with the bottom surface is set to O, the intersection point between the vertical line passing through O is set to H2, the height of H2 is set to h2, and the height in the side surface of the fine concave portion is h3 (=h2/e, where , where e is the base of the natural logarithm) is set to H3. Further, the angle formed by the straight line 1 and the bottom surface is defined as the taper angle θ, and the distance between H2 and H3 in the direction parallel to the bottom surface is defined as the trailing length L. Further, H1, H2, and H3 are located on a line connecting the portion which is the portion where the sector-shaped distortion-like structure is most etched in the horizontal direction.

According to the method of forming a fine three-dimensional structure of the present invention, it is possible to form a fine concave portion having a taper angle θ of 85 degrees or more and 89.99 degrees or less. Further, by setting the depth of the recess formed in the primary isotropic etching step (2A) to 100 nm or less, it is possible to form fine recesses having a trailing length L of 2 μm or less. In other words, according to the method of forming a fine recessed portion of the present invention, it is possible to form a fine recessed portion which is etched in the vertical direction and whose side surface is steeply erected from the bottom. When the width of the 95% depth position of the fine concave portion is W95, the fine concave portion obtained by the method of forming the fine concave portion of the present invention is etched in the vertical direction, and the trailing length of the bottom portion is short. The variation of W10, W50, W90, and W95 is small, and the variation coefficients (W10 to W95) of W10, W50, W90, and W95 are smaller than the variation coefficients (W10 to W90) of W10, W50, and W90. The coefficient of variation (W10 to W95) is preferably 3.5% or less, more preferably 3.2% or less, further preferably 2.5% or less, and most preferably 1.8% or less. Furthermore, a scanning electron microscope (SEM), a transmission electron microscope (TEM), and a scanning transmission electron microscope (STEM) are used using an image analysis software attached or commercially available. The image of the isoelectric microscope is analyzed, whereby the respective values can be obtained. However, as described above, there is also a case where the sector distortion structure cannot be confirmed, and the period P and the depth D of the sector distortion structure cannot be obtained. In this case, the period P of the sector-shaped distortion structure can be calculated from the depth of the formed fine concave portion and the number of cycles of the Bosch process. Further, there is a case where the observation is performed by an atomic force microscope (AFM) instead of an electron microscope, whereby the period P and the depth D of the sector-shaped structural structure can be measured.

Here, by using a wafer having a half inch size (diameter: 12.5 mm), the volume of the chamber can be reduced to 500 mL or less. The volume (V) of the chamber is set to 500 mL or less, and an exhaust device having an exhaust capacity (100 V/sec or more) having a volume of 100 times or more per second of the chamber volume is used, whereby the processing gas can be exchanged at a high speed. Thereby the cycle time can be shortened. The exhausting capacity of the exhaust device is preferably 150 times or more, more preferably 200 times or more, per second of the chamber volume.

The process gas is exchanged at a high speed, and the etching step and the plasma deposition step (2B) are switched in a short time, and the etching is performed little by little, whereby a fine recess having a smoother side surface can be formed. Specifically, etching is performed so that the period P of the sector distortion structure is 40 nm or less, whereby the depth D of the sector distortion structure can be 12 nm or less, and the variation coefficient (W10 to W90) can be set. When it is 3.3% or less, the coefficient of variation (W10 to W95) is set to 3.1% or less, the taper angle is set to 88.6 degrees or more, and the trailing length is set to 0.8 μm or less.

The etching step time is preferably 3.5 seconds or shorter, more preferably 2 seconds or shorter, and still more preferably 1 second or shorter. The ratio of the time of the isotropic etching step (2A) in the etching step to the time in the removal step (2C) may be appropriately adjusted in the range of 90:10 or more and 10:90 or less. Moreover, the ratio of the time of the isotropic etching step (2A) to the time of the removal step (2C) can be solidified in the Bosch process. It can also change. Further, the time of the plasma deposition step (2B) is preferably 3.5 seconds or shorter, more preferably 2 seconds or shorter, and still more preferably 1 second or shorter. Further, the time required for the isotropic etching step (2A), the plasma deposition step (2B), and the removal step (2C), that is, the cycle time is preferably 6 seconds or shorter, more preferably 4 seconds or shorter, and further preferably 2 Less than seconds. If the gas is not sufficiently replaced, the process gas is mixed, and therefore, the cycle time is preferably 0.5 seconds or more.

For example, by using a wafer having a half inch size, the processing gas is exchanged at a high speed, and the cycle time is set to 2 seconds, whereby the Bosch process of 300 cycles can be performed in only 10 minutes (600 seconds). At this time, by adjusting the depth of the recess formed in the primary isotropic etching step (2A) to 33.3 nm, it is possible to form a depth having a depth of 10 μm and a sector-shaped distortion structure of 12 nm or less in 12 minutes. Fine recesses.

The number of cycles of the Bosch process in the method for forming a fine three-dimensional structure of the present invention is not particularly limited. However, in order to form a fine recess having a small depth D and a smooth side surface of the sector-shaped distortion structure, it is preferable to form a fine recess having a desired depth by a Bosch process of 200 cycles or more. The number of cycles is more preferably 300 cycles or more, further preferably 500 cycles or more, and most preferably 1000 cycles or more. Here, the depth of the depression formed in the primary isotropic etching step (2A) is set to 100 nm or less.

Here, by using a wafer having a half inch size (diameter: 12.5 mm), the inner diameter of the chamber in which the plasma is generated can be 20 mm or more and 60 mm or less. By reducing the space for generating plasma, it is possible to achieve miniaturization and power saving of a machine required to generate plasma, for example, an output of less than 50 W can be made, and a device of 50 W is required to be licensed according to the Japanese radio law.

The so-called skin layer of the space in which the plasma is generated is close to the inner wall of the chamber, and is a region where no plasma is generated by the skin effect when high-frequency power is supplied to the coil. The higher the frequency of the high-frequency power, the thinner the thickness of the skin layer in the diameter direction, and the lower the frequency of the high-frequency power, the thicker the thickness of the skin layer in the diameter direction. Therefore, if the frequency of the high-frequency power is small, the skin layer becomes too thick, and the region where the plasma is generated cannot be sufficiently ensured. However, by setting the frequency of the high-frequency power to 40 MHz or more, plasma can be generated even if the area is narrow. Further, by setting the magnitude of the high-frequency power to 2 W or more, the generated plasma can be stably maintained. By setting the frequency of the high-frequency power to 40 MHz or more which is larger than the general 13.56 MHz, even if the high-frequency power is as small as 2 W, it is possible to provide sufficient energy for generating plasma. Further, when the high-frequency power is reduced, the etching rate is reduced. Therefore, the depth of the groove formed in the primary isotropic etching step (2A) is shallow, and it is suitable to form a fine concave portion having a smooth side surface.

As described above, according to the microscopic structure forming method of the present invention using the maskless exposure and the Bosch process, it is possible to form a fine three-dimensional structure having vertical and smooth side faces and faithful to the resist to be drawn. pattern. Further, if necessary, the method for forming a fine three-dimensional structure of the present invention can perform an additional step of forming a protective layer such as an oxide film, a nitride film, or a metal plating layer, and a cutting step.

"Micro-stereoscopic structure" Fig. 6 is a schematic view showing a cross-sectional view in the depth direction of an embodiment of the fine three-dimensional structure of the present invention. The fine three-dimensional structure 100 according to the embodiment includes a fine concave portion 110 formed on the tantalum substrate W and including a portion from which the tantalum is removed, and a period P of 100 nm or less and a depth D of 30 nm or less are formed on the side surface of the fine recessed portion. Sector-shaped distortion structure (not shown). In the fine three-dimensional structure of the present invention, the fine concave portion is formed by etching the tantalum substrate in the vertical direction. The portion where the ruthenium substrate is not etched and remains remains as the fine convex portion 130. Therefore, the fine concave portion is adjacent to the fine convex portion, and the fine convex portion and the tantalum substrate contain the same material in succession without an interface. The shape of the fine three-dimensional structure is not particularly limited, and examples thereof include a column, a quadrangular prism, a circular hole, a square hole, a linear or curved ridge, a concave strip, and the like, or a combination thereof.

The fine recess has a depth of 20 μm or less and a width of 3 μm or more. The depth of the fine concave portion, that is, the height of the fine convex portion is more preferably 15 μm or less, and still more preferably 12 μm or less. The depth of the fine concave portion (the height of the fine convex portion) is preferably 500 nm or more, more preferably 1 μm or more, and still more preferably 2 μm or more. Further, the width of the fine concave portion is preferably 4 μm or more, and more preferably 5 μm or more. The fine concave portion is etched substantially vertically, and the fine convex portion is substantially vertically erected with respect to the ruthenium substrate. Specifically, when the widths of the 10% depth position, the 50% depth position, and the 90% depth position of the fine concave portion are W10, W50, and W90, respectively, the coefficient of variation (W10 to W90) is 5% or less. The coefficient of variation (W10 to W90) is preferably 3.5% or less, more preferably 3% or less, still more preferably 2.7% or less, and most preferably 2% or less. Further, when the width of the 95% depth position is W95, the coefficient of variation (W10 to W95) of W10, W50, W90, and W95 is preferably 3.5% or less, more preferably 3.2% or less, and still more preferably 2.5%. Hereinafter, the optimum is 1.8% or less.

The period P of the sector-shaped distortion structure on the side of the fine concave portion is 100 nm or less, preferably 60 nm or less, more preferably 40 nm or less, further preferably 30 nm or less, and most preferably 20 nm or less. Further, the depth D of the sector-shaped structural structure is 30 nm or less, preferably 20 nm or less, more preferably 15 nm or less, further preferably 12 nm or less, and most preferably 5 nm or less. Further, the taper angle θ of the fine concave portion is preferably 86 degrees or more, more preferably 88 degrees or more, still more preferably 89 degrees or more, and most preferably 89.5 degrees or more. The trailing length L is preferably 2 μm or less, more preferably 1.5 μm or less, further preferably 1 μm or less, and most preferably 0.6 μm or less. Further, by using an image analysis software attached or commercially available, an image of an electron microscope such as SEM, TEM, or STEM can be analyzed, whereby the respective values can be obtained. However, there is also a case where the sector distortion structure cannot be confirmed from the electron microscope image, and the period P and the depth D of the sector distortion structure cannot be obtained. In this case, the period P of the sector-shaped distortion structure can be calculated from the depth of the formed fine concave portion and the number of cycles of the Bosch process. Further, there is a case where the observation is performed by an atomic force microscope (AFM) instead of the electron microscope, whereby the period P and the depth D of the sector-shaped structural structure can be measured.

A wafer having a half inch size (diameter: 12.5 mm) is used as the ruthenium substrate, whereby the cycle time of the Bosch process when the fine concave portion is formed can be set to 6 seconds or less. Since the etching time can be further reduced by shortening the cycle time, the depth D of the sector-shaped distortion structure is further reduced, and the side surface can be made smoother. The period P of the sector-shaped distortion structure can be set to 40 nm or less, and the depth D can be set to 12 nm or less. In addition, the coefficient of variation (W10 to W90) can be set to 3.4% or less, the coefficient of variation (W10 to W95) to be 3.1% or less, the taper angle to be 88.6 degrees or more, and the trailing length to be 0.8 μm or less.

Furthermore, the fine three-dimensional structure of the present invention is not limited to the above embodiment. For example, the top of the fine protrusions may also be covered by a resist that is exposed without a mask. At this time, the film thickness of the central portion of the resist is thicker than the thickness of the boundary portion, and the width of the undercut portion of the mask is 30 nm or less. Further, by performing the method of forming the fine three-dimensional structure of the present invention a plurality of times, it is possible to form a fine three-dimensional structure having fine concave portions having different depths and fine convex portions having different heights.

Compared with the conventional fine three-dimensional structure, the fine three-dimensional structure of the present invention has a smooth side surface, excellent verticality of each surface, and is faithful to the drawn resist pattern. The use of the fine three-dimensional structure of the present invention is not particularly limited. For example, the period P and the depth D of the sector-shaped distortion-like structure are sufficiently smaller than the wavelength of light, and the perpendicularity of the fine three-dimensional structure is excellent, and the attenuation when light is reflected at the interface is small, and therefore, it can be suitably used as an optical waveguide. Further, since the desired shape can be formed faithfully to the resist pattern, it is suitable as an optical element such as a diffraction grating or an hologram. Further, since the side surface is smooth and the resistance during liquid flow is small, it can also be used as a micro flow path or a microreactor. In this case, since the unevenness on the side surface is small and the solid matter is not easily caught, it is particularly suitable for applications in which cells or microorganisms flow. In addition, it can also be used as a die for imprinting, MEMS, Nano Electro Mechanical Systems (NEMS), and the like. Example

Experiment 1 A negative photoresist was spin-coated on a tantalum wafer having a half inch size so that the film thickness after drying became 1 μm, and the negative photoresist was dried. After one exposure was performed by a DLP exposure apparatus, development was performed to draw a resist pattern. The shape of the exposure spot is 0.5 μm square. Using a plasma etching apparatus having a chamber volume of 500 ml and an exhaust speed of 80 L/sec, a Bosch process with a cycle time of 2 seconds of 300 cycles was performed under the following conditions, and the cycle time was 2 seconds in the Bosch process. The etching step and the plasma deposition step (2B) were each 1 second. The isotropic etching step (2A) in the etching step was 0.6 seconds, the removal step (2C) was 0.4 seconds, and the total time of the Bosch process was 600 seconds (= 2 seconds × 300 cycles). Pressure: 10 Pa Frequency of high frequency power: 100 Hz Size of high frequency power: 25 W Bias power: 2 W Etching: SF ₆ , 8 ml/min Plasma deposition: C ₄ F ₈ , 8 ml/min Then, The resist pattern is removed using an ashing device to form a fine three-dimensional structure.

The drawn resist pattern and the resulting fine three-dimensional structure were observed using a scanning electron microscope. In Fig. 7 and Fig. 8, a cross-sectional image and a plan view image of a resist pattern having a line and space of 4 μm are respectively shown. Further, in FIGS. 9 to 11 , a plan view image of a fine three-dimensional structure, a cross-sectional image of a portion having a line and space of 4 μm, and a cross-sectional image of a portion having a line and a space of 2 μm are respectively shown.

The resist pattern is tailed due to the non-uniformity of the light exposure without the mask exposure. Further, the resist pattern has a zigzag step with respect to the direction oblique to the scanning direction, and after the resist pattern is etched as a mask, a fine three-dimensional structure that directly reflects the zigzag step is formed.

A portion of 4 μm in line and space forms a fine recess with a depth of 12.0 μm. Even if the cross-sectional image is enlarged by 500,000 times, the sector-shaped structure is not confirmed. Therefore, the depth D of the sector-shaped distortion-like structure formed on the side surface is 12 nm or less. Further, the period P of the sector-shaped distortion-like structure calculated from the depth of the fine concave portion and the number of cycles is 40.0 nm. W10, W50, and W90 of the fine concave portion were 5.00 μm, 4.77 μm, and 4.69 μm, respectively, and the coefficient of variation (W10 to W90) was 3.34%. Further, W95 was 4.69 μm, and the coefficient of variation (W10 to W95) was 3.06%. The taper angle is 88.6 degrees and the trailing length is 0.59 μm. Each measured value is shown in Table 1. For a portion having a line and space of 4 μm, etching can be performed substantially in the vertical direction, and the portion is steeply erected from the bottom. Moreover, the sector-shaped structure was not confirmed, and the side surface was smooth.

A portion of 2 μm in line and space forms a fine recess with a depth of 11.0 μm. Even if the cross-sectional image is enlarged by 500,000 times, the sector-shaped structure is not confirmed. Therefore, the depth D of the sector-shaped distortion-like structure formed on the side surface is 12 nm or less. Moreover, the calculated sector-shaped structural period P is 36.7 nm. W10, W50, and W90 of the fine concave portion were 3.09 μm, 2.85 μm, and 2.61 μm, respectively, and the coefficient of variation (W10 to W90) was 8.06%. Further, W95 was 2.61 μm, and the coefficient of variation (W10 to W95) was 8.24%. The taper angle is 88.5 degrees and the trailing length is 0.40 μm. Each measured value is shown in Table 1. For a portion having a line and space of 2 μm, the width of the space is narrow, and the processing gas is hard to intrude into the inside, and therefore, the etching rate is slowly lowered. Therefore, the coefficient of variation (W10 to W90) increases as compared with the portion where the line and space are 4 μm. The taper angle of the portion where the line and space are 4 μm and 2 μm is almost unchanged. The reason is that the difference between W10 and W50 (W10-W50) of the line and space of 4 μm and 2 μm is approximately the same, 0.23 μm and 0.24 μm, respectively. However, the difference between W50 and W90 (W50-W90) in the line and space of 4 μm and 2 μm is very different, the difference is 0.08 μm, 0.24 μm, and the etching rate is as follows in the case of 2 μm line and space. The fine recesses become deeper and continue to decrease.

Experiment 2 A microscopic three-dimensional structure was formed in the same manner as in Experiment 1, except that the resist pattern was drawn by performing multiple exposure (divided into five in the vertical and horizontal directions) by the DLP exposure apparatus. Multiple exposures were performed while moving the exposure dots of 0.5 μm square in the vertical and horizontal directions by 0.1 μm. Further, the total exposure energy cumulative amount of the multiple exposures was equal to the exposure energy of Example 1.

The drawn resist pattern and the resulting fine three-dimensional structure were observed using a scanning electron microscope. A cross-sectional image of a resist pattern having a line and space of 4 μm is shown in FIG. Further, in Fig. 13 and Fig. 14, a plan view image of a fine three-dimensional structure and a cross-sectional image of a portion having a line and a space of 4 μm are shown.

After multiple exposures to the unmasked exposure, the resist pattern trails. Further, since the zigzag step of the resist pattern is reduced by multiple exposure, a fine three-dimensional structure which is very smooth in the horizontal direction is formed as compared with the fine three-dimensional structure of Experiment 1.

A portion of 4 μm in line and space forms a fine recess with a depth of 10.2 μm. Even if the cross-sectional image is enlarged by 500,000 times, the sector-shaped structure is not confirmed. Therefore, the depth D of the sector-shaped distortion-like structure formed on the side surface is 12 nm or less. Moreover, the calculated sector-shaped structural period P is 34.0 nm. W10, W50, and W90 of the fine concave portion were 4.83 μm, 4.64 μm, and 4.59 μm, respectively, and the coefficient of variation (W10 to W90) was 2.70%. Further, W95 was 4.59 μm, and the coefficient of variation (W10 to W95) was 2.45%. The taper angle is 89.1 degrees and the trailing length is 0.76 μm. Each measured value is shown in Table 1. Even if a resist pattern drawn by maskless exposure is used, the portion having a line width of 4 μm can be etched substantially in the vertical direction, and the portion is also steeply erected from the bottom. Moreover, the sector-shaped structure was not confirmed, and the side surface was smooth.

Experiment 3 A microscopic three-dimensional structure was formed in the same manner as in Experiment 2 except that the etching gas was allowed to flow simultaneously with the protective film forming gas in place of the Bosch process. The etching conditions are as follows. Etching time: 600 seconds Pressure: 10 Pa Frequency of high frequency power: 100 Hz

The size of high frequency power: 25W

Bias voltage: 2W

Etching: SF ₆ , 4ml/min

Plasma deposition: C ₄ F ₈ , 4ml/min

A fine concave portion having a depth of 5.12 μm was formed by observing a portion of the formed fine three-dimensional structure having a line and a space of 4 μm by a scanning electron microscope. Furthermore, the experiment 3 did not use the Bosch process, and therefore, no sector-shaped structure was formed.

W10, W50, and W90 of the fine concave portion were 5.23 μm, 5.56 μm, and 5.23 μm, respectively, and the coefficient of variation (W10 to W90) was 3.57%. Further, W95 was 4.26 μm, and the coefficient of variation (W10 to W95) was 11.08%. The taper angle is 94.3 degrees and the trailing length is 0.48 μm. Each measured value is shown in Table 1.

In Experiment 3, the conditions of etching and plasma deposition were poorly set, the taper angle was 94.3 degrees, and etching was not possible in the vertical direction, and the width was wide to the maximum of 5.80 μm in the vicinity of the 80% depth position of the fine concave portion.

100‧‧‧Microscopic structure

110‧‧‧Micro recess

111‧‧‧ openings

112‧‧‧ bottom

113‧‧‧ side

114‧‧‧ sectoral distortion structure

120‧‧‧resist pattern

130‧‧‧Micro-convex

201‧‧‧Light source

202‧‧‧DMD

203‧‧‧Reducing the projection lens

300‧‧‧ Plasma etching device

301‧‧ ‧ chamber

302‧‧‧ gas supply mechanism

303‧‧‧ coil

304‧‧‧Circuit power supply mechanism

305‧‧‧Abutment

306‧‧‧Base power supply agency

307‧‧‧Exhaust device

401‧‧‧Resist

402‧‧‧ dent

403‧‧‧Protective film

404‧‧‧ sectoral distortion structure

D‧‧‧Deep

H0‧‧‧Side upper end of the fine recess

h0‧‧‧Deep depth of the concave

H1‧‧‧ middle height location on the side

H1‧‧‧ Height

H2‧‧‧ intersection

H2‧‧‧ height

H3‧‧‧Location

H3‧‧‧ Height of the side of the fine recess

L‧‧‧ Straight line

L‧‧‧Tail length

O‧‧‧ intersection

P‧‧ cycle

W‧‧‧矽 substrate

W10‧‧‧Width

W50‧‧‧Width

W90‧‧‧Width

Θ‧‧‧ cone angle

Figure 1 is a schematic illustration of a maskless exposure, i.e., DLP exposure. Fig. 2 is a view showing the light intensity when four exposures are performed by moving the exposure point without mask exposure. 3 is a cross-sectional view showing a configuration example of a plasma etching apparatus. 4 is a schematic view showing a cross section in the depth direction of a fine concave portion formed by the method for forming a fine three-dimensional structure of the present invention. Fig. 5 is a view for explaining a shape of a fine concave portion formed by the method for forming a fine three-dimensional structure of the present invention. Fig. 6 is a schematic view showing a cross section in the depth direction of an embodiment of the fine three-dimensional structure of the present invention. Fig. 7 is a cross-sectional image observed by a scanning electron microscope of a resist pattern having a line and space of 4 μm as depicted in Experiment 1. Fig. 8 is a plan view of a resist pattern having a curve width of 4 μm as depicted in Experiment 1 observed by a scanning electron microscope. Fig. 9 is a plan view of a fine three-dimensional structure having a curve width of 4 μm prepared in Experiment 1 as observed by a scanning electron microscope. Fig. 10 is a cross-sectional image observed by a scanning electron microscope of a fine three-dimensional structure having a line and space of 4 μm prepared in Experiment 1. Fig. 11 is a cross-sectional image observed by a scanning electron microscope of a fine three-dimensional structure having a line and space of 2 μm prepared in Experiment 1. Fig. 12 is a cross-sectional image observed by a scanning electron microscope of a resist pattern having a line and space of 4 μm as depicted in Experiment 2. Fig. 13 is a plan view of a fine three-dimensional structure having a curve width of 4 μm prepared in Experiment 2, which was observed by a scanning electron microscope. Fig. 14 is a cross-sectional image observed by a scanning electron microscope of a fine three-dimensional structure having a line and space of 4 μm prepared in Experiment 2. 15(a) to 15(c) are views for explaining the progress of etching when the trailing resist is used as a mask. Figure 16 is a schematic illustration of light intensity in an exposure point without mask exposure. 17(a) to 17(d) are diagrams for explaining the steps of the Bosch process.

Claims (17)

A method for forming a fine three-dimensional structure, comprising: a step (1) of forming a resist pattern drawn by maskless exposure on a substrate; an isotropic etching step (2A) by waiting Forming a recess on the substrate by etch etching; a plasma deposition step (2B) of depositing a protective film on the inner wall of the recess and the resist pattern; removing step (2C) by omnidirectional An isotropic etching to remove the protective film on the bottom surface of the recess; and a step (2) of sequentially performing an isotropic etching step (2A), a plasma deposition step (2B), and a removing step (2C), Thereby, fine recesses are formed in the substrate. The method of forming a fine three-dimensional structure according to claim 1, wherein the maskless exposure is multiple exposure. The method for forming a fine three-dimensional structure according to the first or second aspect of the invention, wherein the widths of the 10% depth position, the 50% depth position, and the 90% depth position of the fine concave portion are respectively set to W10 and W50. At W90, the variation coefficients (W10 to W90) of W10, W50, and W90 are 5% or less. The method for forming a fine three-dimensional structure according to the first or second aspect of the invention, wherein the period P of the sector-shaped distortion-like structure of the side surface of the fine concave portion is 100 nm or less. The method for forming a fine three-dimensional structure according to the first or second aspect of the invention, wherein the depth D of the sector-shaped structural structure of the side surface of the fine concave portion is 30 nm or less. The method of forming a fine three-dimensional structure according to the first or second aspect of the invention, wherein the substrate has a diameter of 0.5 inch. The method for forming a fine three-dimensional structure according to the first or second aspect of the invention, wherein the cycle time is 0.5 seconds or longer and 6 seconds or shorter. The method for forming a fine three-dimensional structure according to claim 6, wherein when the widths of the 10% depth position, the 50% depth position, and the 90% depth position of the fine concave portion are respectively set to W10, W50, and W90, The variation coefficients (W10 to W90) of W10, W50, and W90 are 3.5% or less. The method for forming a fine three-dimensional structure according to claim 6, wherein the depth D of the sector-shaped distortion-like structure of the side surface of the fine concave portion is 12 nm. under. A fine three-dimensional structure having a fine concave portion having a depth of 20 μm or less and a width of 3 μm or more on a substrate, and a width of a 10% depth position, a 50% depth position, and a 90% depth position of the fine concave portion, respectively When W10, W50, and W90 are set, the coefficient of variation (W10 to W90) of W10, W50, and W90 is 5% or less. The fine three-dimensional structure according to claim 10, wherein a period P of the sector-shaped distortion-like structure of the side surface of the fine concave portion is 100 nm or less. The fine three-dimensional structure according to claim 10, wherein the sector-distortion structure has a depth D of 30 nm or less. The fine three-dimensional structure according to claim 10, wherein the fine three-dimensional structure includes: a fine convex portion adjacent to the fine concave portion; and a resist covering a top portion of the fine convex portion, The film thickness of the end portion of the resist is thinner than the film thickness at the center portion. The fine three-dimensional structure according to claim 13, wherein a width of the undercut of the upper end portion of the fine convex portion is 30 nm or less. The fine three-dimensional structure as described in claim 10 or 11, wherein The substrate has a diameter of 0.5 inch. The fine three-dimensional structure according to claim 15, wherein the coefficient of variation (W10 to W90) is 3.5% or less. The fine three-dimensional structure according to claim 15, wherein the sector-distortion structure has a depth D of 12 nm or less.