JP2003091070A - Three-dimensional structure and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tribological product holding a lubricant on the surface of a structural member by combining a three-dimensional structure and an ultrafine structure. SOLUTION: The objective shape is simulated and a mask with a GM pattern is formed using a CAD software. A double-faced polished cemented carbide is prepared as a base material and a high sensitivity photosensitive material is applied on the surface of the base material with a spinner and subjected to reduced exposure with a stepper using the mask without defocusing. After developing and rinsing the photosensitive material, hardening is carried out with a UV hardening device while retaining the rugged fine shape of the surface of the photosensitive material. When the shape of the photosensitive resist material is transferred to the cemented carbide by a dry etching method, micro- concaves 14 of about 0.02 μm diameter are formed in micro-concaves 12 in the surface 10b of a structural component of the cemented carbide. A lubricative material is dropped on the surface and the structural component is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of micromachining products, friction and wear (tribology) (fields related to surface lubrication of structural members, for example, the interior of automobile engines, the field of moving stage surfaces, etc., for reducing the friction coefficient).
Products, photocatalysts, and other articles having a three-dimensional structure, and methods for manufacturing the same. In particular, the manufacturing method involves exposing a substrate coated with a photosensitive material through an exposure mask to develop and rinse the substrate. And then forming a three-dimensional structure pattern on the photosensitive material, curing the photosensitive material pattern, and using the mask as a mask to transfer the pattern to the substrate to form a three-dimensional structure. It is a thing.

[0002]

2. Description of the Related Art As a refracting surface or a reflecting surface of an optical element, a special surface shape represented by a spherical surface or an aspherical surface has been used. Further, in recent years, a special surface shape has been required for microlenses and the like in connection with liquid crystal display elements, liquid crystal projectors and the like. Therefore, as a method of forming a refraction surface and a reflection surface without using molding or polishing, a layer of photoresist (a typical example of a photosensitive material) is formed on the surface of an optical substrate, and a two-dimensional pattern is formed on this photoresist layer. Density distribution mask (gradation mask (GM)) with a typical transmittance distribution
Through exposure, and develop or rinse the photoresist to obtain a convex or concave shape as the surface shape of the photoresist, and then anisotropically etch the photoresist and the optical substrate to obtain the surface shape of the photoresist. It is known to obtain a desired shape of a refracting surface or a reflecting surface of a three-dimensional structure on the surface of an optical substrate by engraving and transferring the same onto an optical substrate (Japanese Patent Laid-Open No. 7-230159, Japanese Patent Publication No. See JP-A 8-504515).

There, as a concentration distribution mask used for obtaining a special surface shape of a three-dimensional structure such as a refracting surface or a reflecting surface, a two-dimensional transmission in which the transmittance changes stepwise according to the surface shape. A density distribution mask having a rate distribution is used.

In the density distribution mask described in Japanese Patent Publication No. 8-504515, the mask pattern is divided into unit cells called light transmission apertures in order to form a two-dimensional transmittance distribution pattern. The opening size of each unit cell is
The amount of light transmission or the amount of light shielding is set according to the height of the corresponding position of the photoresist pattern to be formed. The light-shielding film pattern of the unit cell is composed of two types, that is, a region where the light-shielding film exists and the light transmittance is 0%, and a region where the light-transmitting film does not exist and the light transmittance is 100%. The region of 0% and the region of 100% light transmittance are arranged in one direction so as to be one lump. The minimum size of the light-shielding film pattern is an ultrafine pattern that is shorter than the wavelength of light used for exposure.

As a method of manufacturing the same, an electron beam (E
B) The drawing method by irradiation is adopted. JP 7-2
Japanese Patent No. 30159 describes a method of manufacturing a concentration distribution mask by changing the light transmission amount in the unit cell by changing the laser light irradiation light amount at the time of drawing in the unit cell.

In the field of tribology of friction and wear, it is required to retain a lubricant (oil) on the surface of structural members. Therefore, a method of mechanically forming a V-groove or a concave groove on the surface of a structure and retaining the lubricating oil has been proposed, but an ultra-fine three-dimensional structure, particularly a fine three-dimensional surface It is not known to form a structure to reduce friction and wear.

In the field of photocatalysts, in titanium oxide (TiO ₂ ) having anatase type and Brooklite type crystal structures, decomposition reaction of burning (chemical reaction) an organic substance occurs on the surface of titanium oxide by ultraviolet irradiation, and ,
It has been known that water is decomposed into H and O by ultraviolet light and a hydrophilization reaction occurs.

In order to industrially efficiently obtain the effect of such a reaction on the photocatalyst surface, an organic substance in the air or water diffuses and reaches the catalyst surface before the photocatalytic reaction occurs and is adsorbed there. Needs to be done. The surface area of the material, including fine irregularities, affects it. Therefore, it is desirable to use a porous material having a large surface area as the photocatalyst.

In order to produce a porous material having a large surface area, for example, when titanium oxide is used as a catalyst, a method of producing it at a low temperature so that sintering does not proceed so as not to promote the bonding of titanium oxides to each other, A method for producing a surface thin film by a sol-gel method and a method for producing it under the condition that the amount of binder is slightly small are known.

The "sensitivity curve" of the photosensitive material is given as shown schematically in FIG. The sensitivity curve differs depending on the photosensitive material, where a is a high-sensitivity photosensitive material and b is a low-sensitivity photosensitive material. A is the coating thickness of the photosensitive material, CEL (contrast / enhancement / lithography) is the amount of the photosensitive material removed in the initial stage of exposure, which is the CEL of the high-sensitivity photosensitive material.
(High) is larger than CEL (Low) of the low-sensitivity photosensitive material. D1 is the irradiation light amount at which the low-sensitivity photosensitive material starts to be exposed
D2 is the irradiation light amount at which the high-sensitivity photosensitive material starts to be exposed, and is the initial irradiation light amount due to each CEL effect. D3 is the amount of irradiation light required to remove the entire film thickness of the high-sensitivity photosensitive material, D4
Is the amount of irradiation light required to remove the entire film thickness of the low-sensitivity photosensitive material,
These are the exposure amounts when each photosensitive material is exposed to the bottom.

Since the light transmission coefficient has a different light absorption coefficient depending on the molecular structure contained in the photosensitive material, the CEL amount and the sensitivity curve differ depending on the photosensitive material. When the light travels through the photosensitive material, the light energy (light quantity) depends on the depth.
Is reduced. That is, the thickness (depth) of the photosensitive material and the irradiation light energy amount are in an inversely proportional relationship that decreases with an exponential function. Therefore, if the "light transmittance" and the residual film amount of the photosensitive material are obtained from the experimental data, it is possible to form a resist film thickness distribution having a distribution in the thickness direction of the photosensitive material.

As can be seen from FIG. 3, when the low-sensitivity photosensitive material is used, gradation can be obtained in the range of D1 to D4, and the gradation range can be widened, but the sharpness of the pattern is improved. Difficult to make On the other hand, when the high-sensitivity photosensitive material is used, gradation can be obtained only in the range of D2 to D3, and the range of gradation cannot be widened, but it is easy to improve the sharpness of the pattern.

[0013]

The present invention has investigated the use of high sensitivity photosensitive materials to improve pattern sharpness. Prior art table 8-504
The density distribution reticle mask disclosed in Japanese Patent No. 515 has unit cells as shown in FIGS. 1A and 1B, and when a high sensitivity photosensitive material is exposed using such a density distribution reticle mask. The cross-sectional shape after development is shown in Figure 1.
As shown by the solid line in (A), a gradation step of each unit cell is large in the photosensitive material, so that the shape is not smooth.

With the high-sensitivity photosensitive material, since the light transmittance distribution in the unit cell of the mask is transferred as it is, fine irregularities can be formed on the surface. Therefore, the first aspect of the present invention
The purpose of is to provide a three-dimensional structure having fine irregularities on the surface.

In the tribology field of friction and wear, since the structural members are made of high-strength, superhard material metal, it is not possible to manufacture a fine structure on the surface of the structure during machining of the structural members by machining. There wasn't. A second object of the present invention is to retain a lubricant on the surface of a structural member by combining a three-dimensional structure and an ultrafine structure in the tribological field of friction and wear.

In the field of photocatalysis, if a material having a large surface area is to be produced, the conventional production method has a problem that the production process is different for each target material. A third object of the present invention is to facilitate the production of a photocatalytic structure having a large surface area.

A fourth object of the present invention is to provide a method for producing a three-dimensional structure having fine irregularities on the surface thereof with high accuracy and at low cost, which is suitable for application to tribological products, photocatalysts and other products. That is.

[0018]

The three-dimensional structure of the present invention has fine irregularities on its surface, and a plurality of irregularities are formed within a region of 1/200 or less of the dimension of the three-dimensional structure. The height dimension of the unevenness is 1/1000 or more of the height of this three-dimensional structure.

The unevenness is 1/200 of the three-dimensional structure size.
This is because it becomes difficult to make the target shape smoother as the size becomes larger. Further, if the height dimension of the unevenness is smaller than 1/1000 of the height of this three-dimensional structure, the intended three-dimensional structure having fine unevenness on the surface is expected when applied to a tribological product or a photocatalyst. This is because it is difficult to achieve the above-mentioned object and it is difficult to maintain the structure of the photosensitive material pattern during manufacturing.

The tribological product of the present invention is one in which a lubricant is held on the surface of fine irregularities of the three-dimensional structure of the present invention. The photocatalyst of the present invention is obtained by coating the surface of fine irregularities of the three-dimensional structure of the present invention with a photocatalyst layer.

In the manufacturing method of the present invention, a substrate coated with a photosensitive material is exposed through an exposure mask, developed and rinsed to form a three-dimensional structural pattern on the photosensitive material, and then the photosensitive material is exposed. The material pattern is cured, and the pattern is transferred to the substrate by dry etching using the material pattern as a mask to form a three-dimensional structure. At that time, the exposure mask is provided with a plurality of unit cells having a pattern in which the light transmitting portion is decomposed in multiple stages so as to determine the area of the light shielding portion. Using a high-sensitivity photosensitive material that is transferred as
As a photosensitive material pattern after rinsing, fine irregularities are formed on the surface of the three-dimensional overall structure in accordance with the dimensions of the light transmission region of the pattern in the unit cell of the mask. Then, in order to obtain a three-dimensional structure having both a required three-dimensional structure and an ultrafine structure, the photosensitive material pattern is cured in a state with unevenness on the surface, and it is used as a mask to form a pattern on the substrate by a dry etching method. Is transferred to form a three-dimensional structure having fine irregularities on the surface corresponding to the light transmission pattern in the unit cell of the mask.

Here, the high-sensitivity photosensitive material has a γ value of 1.75 or more. A material having a γ value of less than 1.75 is called a low-sensitivity photosensitive material. The γ value is a numerical value given by the following definition. Referring again to FIG. 3, the amount of irradiation light (indicated as D1 or D2) at which the photosensitive material starts to be exposed is represented as D _0, and the amount of irradiation light required for removing the entire film thickness of the photosensitive material (indicated as D3 or D4). ) Is represented by D, the γ value is defined as γ = 1 / (logD−logD ₀ ). The larger the γ value, the higher the sensitivity and the better the resolution.

Exposure mask (reticle) used in the present invention
Can be produced by any of the methods described in JP-A-8-504515 and JP-A-7-230159. The difference between the two methods is
Approximately unit cell size, light source at the time of production, digital method or analog method.

When the exposure mask is manufactured by the method described in Japanese Patent Publication No. 8-504515, the light-shielding portion of the exposure mask is digitally formed by an ultrafine pattern, and the light-transmitting portion is submicron. A plurality of unit cells having a pattern formed and decomposed in multiple stages will be provided. Further, an exposure mask is disclosed in JP-A-7-230159.
When manufactured by the method described in the publication, the exposure mask has a plurality of unit cells having a pattern in which the light transmission distribution has an analog density distribution.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the tribological product of the present invention, the surface of a three-dimensional structure can be made flat or curved, a fine concave structure exists on the surface, and fine irregularities are formed in the fine concave structure. It can be. If the mechanical strength of the structure is sufficient, that is, the function and life of the structure are sufficient under the conditions of industrial use, the surface microstructure for exhibiting the tribological effect has a larger area ratio. Great effect. However, in the case where the fine structure is uniformly formed on the surface, if the ratio of the fine concave structure to the entire surface is more than 50%, the strength and the life of the structure decrease. Therefore, the ratio of the fine concave structure to the entire surface is preferably 50% or less. In the photocatalyst of the present invention, a preferred example of the photocatalyst layer is titanium oxide.

According to the manufacturing method of the present invention, in order to form fine unevenness on the surface of the three-dimensional structure so that the fine unevenness is not unevenly distributed, in the unit cell of the mask, light transmitting portions and light shielding portions are alternately repeated. It is preferable that the pattern has an arranged pattern, and the interval between the light transmitting portions is set according to the target shape.

In order to form sharp fine irregularities on the surface of the photosensitive material pattern, the exposure of the photosensitive material preferably has zero focus blur. This makes it possible to form fine irregularities corresponding to the light-shielding pattern of the mask. The size of the mask is 1/20 of the size on the mask corresponding to the three-dimensional structure to be obtained by the unit cell.
It is preferably 0 or less. This is because if the size of the unit cell is larger than that, it becomes difficult to smooth the target shape.

The height of the fine irregularities on the surface of the photosensitive material pattern is preferably 1/1000 or more of the height of the entire desired structure in the photosensitive material pattern. This is because it becomes difficult to maintain the structure of the photosensitive material pattern when the height dimension of the fine irregularities is smaller than that.

When a photosensitive material pattern is formed on a substrate and the photosensitive material pattern is engraved on the substrate to form an article having a surface shape of a three-dimensional structure, the photosensitive material pattern is formed. First, a method of manufacturing a concentration distribution reticle mask used for exposing a photosensitive material will be described.

First, a desired three-dimensional structure is designed separately. In this design, the correspondence between the sensitivity curve of the photosensitive material and the target shape was clarified, and the transmittance in the unit cell, that is, G
M pattern No. To place. Examples of GM patterns (unit cells) include those shown in FIGS. 1 (C) to 1 (F). (C) staggered array, (D) random array, (E) line and space array, (F)
Shows an example of a one-sided line-and-space arrangement. Of course, the GM patterns that can be used are not limited to these.

Next, based on this design, a concentration distribution reticle mask is manufactured. Specifically, depending on the sensitivity characteristics of the photosensitive material (on the reticle mask) and the light transmission amount distribution of the unit cell according to the desired shape design, irradiation of the laser or electron beam writing (the irradiation of the photosensitive material directly) Exposure).

An example of a method of manufacturing the concentration distribution reticle mask will be shown. As shown in FIG. 4, the following steps are provided. (A) A step of dividing the mask blanks into unit cells (step S1). That is, from the desired three-dimensional shape,
The mask blanks are divided into grids, and the two-dimensional light intensity distribution pattern of the concentration distribution mask to be obtained is arranged and designed in a grid.

(B) A step of determining a light transmission area or a light shielding area of each unit cell based on a mathematically expressed "sensitivity curve" determined from the processing process conditions and the sensitivity of the photosensitive material (step S2).

(C) The light transmission area or the light shielding area determined above is arranged in "each grid" and CAD (Computer Aid)
ed Design), a step of calculating the necessary number of times of drawing, the depth of focus, and the beam diameter and converting them into data (step S3).

(D) Based on the data of step (C), the photosensitive material on the mask blanks is drawn a predetermined number of times (multi-step) under predetermined conditions (depth of focus, beam diameter) (unit cell). Drawing step (step S4). Of course, there is also a case of single exposure. In this step, multi-step drawing is performed as shown in FIGS. Here, as an example, a case is shown in which drawing is divided into four times, and the light transmission amount of the unit cell is determined by drawing as many times as necessary among the four times. The drawing shown as (A) at the top is the drawing pattern when all these four times are drawn.

For each drawing, a plurality of light beams or electron beam beams are simultaneously or sequentially scanned along a scanning line as indicated by an arrow in the upper right of FIG.
It is performed by controlling "N, OFF". The drawing area is set to be different each time.

The change in light transmittance in the unit cell may "change from the center to the periphery", or "the unit cell is divided into grids and the light transmittance changes discontinuously in the grid." In some cases. No light transmission on the grid
It is possible to arrange a “portion having an intermediate transmittance” showing an intermediate value between 100% and 100%. In other words, 0% and 100%
Light transmittance showing an intermediate value of, for example, 30%, 50%, 7
It is possible to arrange a portion having an intermediate transmittance such as 0%.

Since the size of the grid can be reduced, it is possible to dispose grids having intermediate transmittances discontinuously (for example, randomly) as a disposition method.
It is also possible to arrange grids having the same transmittance as a block. When this method is advanced, a continuous concentration distribution arrangement is obtained. In this case, since the intermediate gradation can be made very fine, the unit cell size can be dramatically reduced. Therefore, it is possible to easily form gradation even in a shape in which a desired shape changes rapidly, that is, a shape having a steep gradient. By randomly arranging, there is an advantage that the light sneak amount can be averaged with the adjacent cells.

FIG. 7 shows an example in which "a portion having an intermediate transmittance" showing an intermediate value between 0% and 100% of the optical transmittance is arranged on the grid. Here, a unit cell having a side of 1 μm is divided into 5 × 5 = 25 cells having a side of 0.2 μm. For example,
In the case of arranging five levels of light transmittance portions of white, black, 30%, 50% and 70%, no gradation can be obtained in the case of all white or all black, so in this case 4 gradations are used. is there. Therefore, theoretically, there are 25 × 4 = 100 gradations. That is,
The density change of n steps has n-1 gradation. Further, the gradation differs depending on the division number (grid number) of the unit cell. In the above example, the number of grids × (n−1) = 25 × 4 = 100
Is.

The relationship between the light transmittance of the grid and the gradation was set as shown in Table 1 below.

FIG. 7 shows the light transmittance arrangement of (A) unit cell of 30/100 gradation and (B) unit cell of 60/100 gradation. (C) is 0/100 gradation, 30/10
FIG. 7D shows an example in which 0 gradations and 60/100 gradations are combined, and the number of gradations in each grid is shown by numerical values. The example of FIG. 7 is a case where a random number is generated to form a light transmission density distribution at each grid address.

(E) A step of developing and rinsing the mask blank drawn in step (D) to obtain a three-dimensional photosensitive material pattern (step S5). (F) After that, a step of transferring the photosensitive material pattern shape to the light shielding film 14 by dry etching or wet etching (step S6). A method of manufacturing an article having a three-dimensional structure using the obtained concentration distribution mask is, using the concentration distribution mask, a step of performing reduction exposure on a substrate coated with a photosensitive material by a reduction optical system exposure device, The process of developing and rinsing the exposed photosensitive material to form a photosensitive material pattern with a three-dimensional structure having fine irregularities on the surface, and masking this photosensitive material pattern with fine irregularities on the surface As a step of transferring the pattern to the substrate by a dry etching method.

Comparing the concept of the unit cell in the method of Japanese Patent Publication No. 8-504515 of the above-mentioned reference with that of the present invention, in the method of the reference, as shown in the drawing on the left side of FIG. It is concentrated in a part of the cell.
As a result, the pattern of the light transmitting portion in which the unit cells to be exposed are integrated has a large concave shape when microscopically captured. On the other hand, in the present invention, as shown in the drawing on the right side of FIG. 6, fine unevenness is positively formed in the unit cell, and this uneven shape is positively utilized at the time of manufacturing the structure. As a utilization policy, the concavo-convex shape is utilized as it is and left as a fine structure on the surface of the three-dimensional structure on the surface of the structural member.

Of course, also in the method of the present invention and the method of reference, the light transmission amount as an aggregate of the unit cells is designed so that the desired structure can be manufactured. Further, the present invention is similar to the method of the reference in that it also includes a method of digitally changing the light transmission amount.

The drawing energy is determined by a simulation prepared separately in advance. That is, C in advance
The relationship between the r film thickness and the amount of light transmission is graphed and mathematically expressed.
As described above, the optical density amount of each unit cell is determined and the distribution of the light transmission amount is set so that the set of the light transmission amount (OD) in the unit cell represents a desired shape.

As described above, the three-dimensional structure in which the manufacturing shape is different depending on the direction of the pattern arrangement (where the light transmitting portion is arranged even in the same pattern: the same shape, facing right or left), which is the greatest drawback of the reference method It is possible to solve problems such as the inability to control the fine structure of.

When this method is used, it is easy to obtain the sharpness of the pattern due to the high sensitivity of the photosensitive material. Therefore, it is necessary to manage the sensitivity curve and the manufacturing process that require high control. It becomes possible to manufacture at low cost, easily, and at high manufacturing speed.

It is possible to manufacture a structure having a fine shape on the surface of the structure by using a digital mask having a light transmission amount concentration distribution in the three-dimensional direction by the reduction optical system exposure. By producing a finer uneven structure on the surface of the three-dimensional structure to be formed on the surface of the structure, it becomes possible to give the surface of the structure a special function utilizing surface reaction and surface tension.

[0049]

[Example] (Shape and arrangement in unit cell, and shape and arrangement of "light transmission" and "light shielding" dots) Shape and arrangement in unit cell and shape of "light transmission" and "light shielding" dots And the arrangement will be described. The examples shown below are typical examples, and the unit cell dimensions, dot dimensions, starting point dimensions, etc. should be designed in accordance with the desired shape. It is not limited. That is, since the number of gradations is determined by the size of each unit cell and dot, these sizes are determined by the target shape and the target gradation.

The unit cell shape is the "most" that exhibits the density distribution mask characteristic depending on the desired shape, for example, when a smooth curved surface continues or when it is composed of discontinuous surfaces, depending on the gradation change amount. The optimum shape can be determined by selecting “effective polygon” and “combination thereof”.

Similarly, the size of the unit cell is also determined by the degree of fineness required for the desired shape. That is, when many gradations are required in a short distance,
It is desirable to select unit cells of relatively small size and to make the dot size as small as possible. Further, the increase / decrease of the dot area is input data at the time of input, and the shape may collapse due to the thickening of the laser beam or isotropic etching such as dry etching depending on the mask manufacturing conditions.

(Production of Concentration Distribution Mask Reticle) In the production of the concentration distribution mask reticle, laser light was irradiated using a laser light irradiation device manufactured by Ricoh Optical Co., Ltd. shown in FIG. In this laser light irradiation, the optimum beam shape is determined according to the desired shape,
Apertures can be used to shape polygonal shapes and circular shapes. Further, the laser power may be changed by changing the current value supplied to the laser or by inserting a neutral density filter on the light emitting side.

The laser beam irradiation device shown in FIG. 9 includes a laser beam oscillator 1, a beam splitter 2 for splitting the laser beam from the laser beam oscillator 1 into a plurality of laser beams, a mirror 3 for bending an optical path of the laser beam, and a mirror. Three
From the optical modulator 4, which modulates the laser light bent by the optical modulator 4, the optical modulator 4 which controls the optical modulator 4 by the signal from the data bus to control ON / OFF of each laser light, Optical deflector 6 for deflecting the laser light, the objective lens 7 for condensing the laser light on the resist material layer, the mounted mask blanks in the X direction and the Y direction.
It is composed of an XY stage 8 that moves in the direction, and main components such as a controller 9 that controls the operation of the optical deflector 6 and the operation of the XY stage 8.

This laser light irradiating device controls the operation of the XY stage 8 and ON / OFF and deflection of each laser light according to the design data, so that a desired mask is formed on the resist material layer of the mask blank. Draw a pattern. That is, the resist material layer is irradiated with laser light by this laser light irradiation device so that the light transmission region or the light shielding region of each unit cell has a desired transmittance distribution.
Pattern formation is performed dimensionally. In addition, a substrate surface height detector (AF (automatic focusing) function) is attached.
The focus position is changed by slightly shifting it from the F plane. The laser beam diameter is 0.2 μm in this embodiment.
m, alignment accuracy 0.05 μm, focus position accuracy 0.1
μm. The unit cell shape and the dot shape may be selected as appropriate depending on the intended product.

The CAD data is installed in the laser beam irradiation apparatus shown in FIG. 9, and the density distribution is performed by a predetermined method while controlling the ON / OFF of the XY stage 8 and the laser beam and the beam drawing position and the number of times of drawing. The mask blanks were exposed. Then, development and rinsing were performed by a predetermined method to pattern the resist material layer. Then, the Cr film was patterned by dry etching. In the following specific examples, the CAD program was created with the dot shape as a square circle. In this way, a density distribution mask reticle having a target opening size and a density distribution was manufactured.

Example 1 (Specific Example of Reduction of Friction Coefficient by Micro Concave Structure: XY Stage for Surface Grinding Machine) An XY stage for surface grinding machine made of cemented carbide which requires lubricity is manufactured. did. The manufacturing procedure is shown below. In order to obtain the fine shape shown in FIG. 8, the target shape is simulated and G
Produce M pattern.

Specifically, a microlens array having a concave shape with a diameter of 50 microns is formed on the surface so that the total area of this microlens structure is 30% or less of the total area. At this time, the procedure for GM production is 4 × in the central part.
4 = 16 unit cell (□ 2 on the density distribution mask reticle
.mu.m.times.2 .mu.m, in the actual pattern .quadrature.0.8 .mu.m.times.0.
8 μm), cell No. Place number 80 (without chrome remaining). Also, the four corners of the lens are the cell numbers. Place No. 1 (all remaining chrome). No. 1-No. 8
The “open area” corresponding to each “gradation” is associated with the cell of 0. This relationship is a relationship obtained from the exposure process and the resist sensitivity curve. Of course, if the resist material and process are different, it is necessary to grasp the sensitivity curve each time.

In this embodiment, No. From the pattern next to No. 5, No. In the pattern portion up to 75 (that is, the portion corresponding to the slope of the microlens: the portion where the lens inclination is smooth), the unit cell □ 2 μm × 2 μm is changed to □ 0.2 μm ×
It was divided into small regions of 0.2 μm and divided into 10 × 10 = 100 regions. The light transmission areas of the GM patterns are arranged so that minute unevenness can be formed while giving a predetermined light transmission amount to this area. Specifically, as shown in FIG. 2, the light-transmitting regions are arranged by arranging light-shielding patterns having a width d and a length L in a total of 8 lines in the vertical and horizontal directions. For example, GM
Pattern No. In 40, in the whole area 64 area,
"The light-transmitting region has a width d = 0.4 μm and a length L = 2.0.
A light-shielding pattern of μm was designed. At this time, in the portion near the bottom of the lens, the light transmission region was concentrated and widened. This GM reticle mask was used for reduction exposure with a stepper. Since the purpose of this embodiment is to form a groove for the purpose of oil trap, the groove width is 0.1 on the actual substrate.
It is desirable that the thickness is about μm.

In this example, a cemented carbide having both sides polished was prepared as a base material. A high-sensitivity photosensitive material (manufactured by Tokyo Ohka Kogyo Co., Ltd .: OFPR-5000-800) was applied onto this surface with a spinner. Then 90 on the hot plate
It was prebaked at 120 ° C. for 120 seconds. At this time, the thickness of the photosensitive material was 9.2 μm. Next, reduction exposure was performed using a stepper with a reduction ratio of 1 / 2.5 using the above mask. The exposure conditions are defocus: +0 μm, irradiation amount: 390 mW ×
It is 0.69 seconds (illuminance: 269 mJ).

After the exposure, PEB (Post Exposure Bake) was carried out at 60 ° C. for 180 seconds. Then
The photosensitive material was developed and rinsed. At this time, the resist height was 8.0 μm. Due to the effect of just focus, it was possible to fabricate the fine irregularities on the surface of the photosensitive material as intended.

Thereafter, the resist was hardened by evacuating it while irradiating it with ultraviolet rays for 180 seconds using an ultraviolet curing device. The ultraviolet curing device irradiates with a wavelength that can cure the resist at a wavelength shorter than the wavelength used for exposing the resist. By this operation, the plasma resistance of the resist is improved and the resist can be processed in the next step. The resist height at this time is 7.5μ.
It was m.

Then, on a hot plate, at 5 ° C. for 5 minutes.
A post-post bake (post-bake after hardening) was performed for a minute. At this time, the temperature was increased from 25 ° C. to 95 ° C. with a gradient of 70 ° C./4 minutes (17.5 ° C./minute). Then, it hold | maintained at 95 degreeC for 1 minute. By this heating, while gradually evaporating the solvent in the photosensitive material, in the latter half of the heating, the surface irregularities of the photosensitive material were slightly flowed to obtain the target shape.

Next, the shape of the above-mentioned photosensitive resist material was transferred to the cemented carbide by the dry etching method. For dry etching, a TCP etching apparatus was used and CL ₂ :
While introducing a gas of 10.0 sccm and CF ₄ : 5.5 sccm, a substrate bias voltage: 1200 w, an upper electrode power: 1250 W, and a vacuum degree of 1.5 × 10 ⁻³ Toor (that is, 1.5 mToor) for 40 minutes. I did. The etching rate of the cemented carbide at this time is 0.02
It was μm / min. The etching selection ratio was 0.2, and the shape height after etching was 1.6 μm. The surface roughness was Ra = 0.001 μm or less, which was good.

As a result, as shown in FIG.
Inside the micro concave shape 12 on the surface of the mechanical component surface 10b of the cemented carbide, there was a smaller concave shape 14 having a diameter of about 0.02 μm. When a lubricating material was dropped on the surface of this alloy and the friction coefficient was measured, it was reduced to 1/10 as compared with the case where there was no micro concave shape. A device having a convex mechanical component surface 10a as shown in FIG.
A plane-shaped mechanical component surface 10c as shown in FIG.
It is possible to manufacture the same with the above.

Example 2 (Specific Example of Photocatalyst Surface) Using the same mask as in Example 1, a similar micro-recessed shape was formed on a soda-lime glass substrate, and a finely recessed shape was formed on the surface. At this time, the diameter of the fine concave shape was 0.13 μm.

Next, TiO ₂ having an anatase type crystal structure was formed on the surface by sputtering to 1000
Å Coated. By this film formation, it was possible to form a film on the soda-lime glass substrate in which a decomposition reaction in which an organic substance is burned (chemical reaction) is generated by ultraviolet irradiation. As a result, organic deposits when used outdoors can be naturally removed by sunlight and ultraviolet rays.

Next, on the back surface of this glass, SiO ₂ (2
500Å), Al (1500Å), SiO ₂ (2,500
The materials of Å) were deposited in order. This coating exerts the effect of a reflection mirror. When the photocatalytic reaction occurs, the organic substance needs to diffuse and reach the surface of the catalyst to be adsorbed there. This is affected by the surface area of the material, including the fine irregularities. Therefore, it is desirable that a porous material having a large surface area be used as the photocatalyst, so that the reflection mirror having a fine structure capable of being adsorbed on the surface of the present invention is industrially effective.

[0068]

Since the three-dimensional structure of the present invention has fine irregularities on its surface, holding a lubricant on the surface can impart a special function utilizing surface tension to the surface of the structure. Tribological products can be obtained. Further, by coating the optical catalyst layer on the fine irregularities on the surface of the three-dimensional structure, it is possible to obtain a photocatalyst capable of imparting a special function utilizing the surface reaction to the surface of the structure. For example, an environment-resistant industrial mirror or the like having an optical catalyst layer on the surface can be manufactured. According to the manufacturing method of the present invention, using a digital mask or analog mask having a light transmission amount concentration distribution in the three-dimensional direction,
Exposure to a substrate coated with a high-sensitivity photosensitive material, development and rinsing to form a three-dimensional structural pattern with fine irregularities on the surface of the photosensitive material, and a state with fine irregularities Then, the photosensitive material pattern is cured, and the pattern is transferred to the substrate by dry etching using the mask as a mask to form a three-dimensional structure, so that a three-dimensional structure with fine irregularities on the surface can be formed with high accuracy. It can be offered at a low price.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a unit cell arranged on a density distribution mask.

FIG. 2 is a diagram showing a light transmission region or a light shielding region in a unit cell in an example.

FIG. 3 is an example showing a sensitivity curve of a photosensitive material.

FIG. 4 is a flowchart showing a method of manufacturing a density distribution mask.

FIG. 5 is a diagram showing multi-step drawing, in which (a) to (d) are drawing areas for each time, and (A) is a drawing pattern when all of these four times are drawn.

FIG. 6 is a cross-sectional view of a unit cell comparing the method of the reference with the method of the present invention.

FIG. 7 is a diagram showing a unit cell light transmittance arrangement showing an example in which a unit cell is divided into grids to form a light transmission density distribution. FIG. 7A is a unit cell of 30/100 gradations, and FIG. )
Shows a unit cell of 60/100 gradation, and (C) shows an example in which unit cells of 0/100 gradation, 30/100 gradation and 60/100 gradation are combined.

FIG. 8 is a view showing a cross-sectional shape of a tribology applied product, where (A) is a convex surface of a mechanical component, and (B) is a concave surface.
(C) is a case of a plane.

FIG. 9 is a schematic configuration diagram showing an example of a laser light irradiation device used for manufacturing a concentration distribution mask reticle.

[Explanation of symbols]

10a, 10b, 10c Surface of mechanical parts made of cemented carbide 12 micro concave shape 14 Smaller concave shape

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H095 BB32 BB33 BB36 BC09                 2H097 BA06 BB01 FA02 GB02 JA02                       JA03 LA15                 4K057 DA05 DA11 DA20 DB02 DB17                       DC10 DD03 DD08 DN10

Claims (11)

[Claims] 1. The surface of a three-dimensional structure has fine irregularities, and a plurality of irregularities are formed within a region of 1/200 or less of the dimensions of the three-dimensional structure, and the height of the irregularities is high. The three-dimensional structure is characterized in that the dimension is 1/1000 or more of the height of this three-dimensional structure. 2. A tribological product, wherein a lubricant is held on the surface of the three-dimensional structure according to claim 1. 3. The tribology according to claim 2, wherein the surface of the three-dimensional structure is a flat surface or a curved surface, a fine concave structure is present on the surface, and the fine irregularities are formed in the fine concave structure. Product. 4. The tribological product according to claim 2, wherein the fine concave structure occupies 50% or less of the entire surface. 5. A photocatalyst, characterized in that the surface of the three-dimensional structure according to claim 1 is coated with an optical catalyst layer. 6. The photocatalyst according to claim 5, wherein the optical catalyst layer is titanium oxide. 7. A substrate coated with a photosensitive material is exposed through an exposure mask, developed and rinsed to form a three-dimensional structural pattern on the photosensitive material, and then the photosensitive material pattern is cured. In the method of forming a three-dimensional structure by transferring a pattern to the substrate by dry etching using the mask as a mask, the light-transmitting portion of the exposure mask is decomposed in multiple stages so as to determine the area of the light-shielding portion. A plurality of unit cells having different patterns, wherein the photosensitive material is a highly sensitive photosensitive material to which the pattern in the unit cells is transferred as an uneven shape, and the photosensitive material after development and rinsing is used. As a pattern, fine unevenness is formed on the surface of the three-dimensional overall structure according to the size of the light transmission region of the pattern in the unit cell of the mask, and the photosensitive material pattern also has unevenness on the surface. It is cured in a state of being formed, and a pattern is transferred to the substrate by a dry etching method using it as a mask to form fine unevenness on the surface corresponding to the light transmission pattern in the unit cell of the mask. Method for manufacturing a three-dimensional structure. 8. The unit cell of the mask has a pattern in which light transmitting portions and light shielding portions are alternately and repeatedly arranged,
The method for manufacturing a three-dimensional structure according to claim 7, wherein the intervals of the light transmitting portions are set according to the target shape. 9. The method for manufacturing a three-dimensional structure according to claim 7, wherein the exposure has a focus blur amount of zero. 10. The mask has one of the dimensions on the mask corresponding to the three-dimensional structure to be obtained from the dimensions of the unit cell.
It is / 200 or less, The manufacturing method of the three-dimensional structure in any one of Claim 7 to 9. 11. The method for manufacturing a three-dimensional structure according to claim 7, wherein the height of the unevenness is 1/1000 or more of the height of the entire desired structure in the photosensitive material pattern.