JPH1152114A - Method for manufacturing element having fine concavo-convex pattern - Google Patents

Abstract

(57) [Abstract] [Object] An element capable of forming a fine concavo-convex pattern on an arbitrary basic curved surface (including a plane) irrespective of whether the surface is spherical or aspheric, and whether or not the aspheric surface is rotationally symmetric. (lens,
Mirror, mold, etc.). [Constitution] A step of processing a basic curved surface on which a fine uneven pattern is formed on an element material; a mask forming step of forming a mask corresponding to a convex portion of the fine uneven pattern on the processed basic curved surface; And a mask removing step of removing a mask remaining on the surface of the basic curved surface by removing a basic curved surface of the element material of the portion and forming a concave portion. And a method of manufacturing a device having a fine concavo-convex pattern in which a mask removing step is performed a plurality of times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a device having a fine uneven pattern.

[0002]

2. Description of the Related Art For example, these elements (lenses, mirrors, molding dies, etc.) consisting of spherical or aspherical surfaces
Conventionally, when forming the shape of a diffraction grating, a precision lathe was used. That is, the cutting tool is slowly moved along the radial direction of the element material rotating at a high speed to simultaneously create a macroscopic shape of a spherical surface or an aspherical surface and a fine uneven shape as a diffraction grating. For this reason, the diffraction grating that can be created is limited to those in which the arrangement (pattern) of the diffraction grooves is rotationally symmetric with respect to the rotation axis.

[0003]

An object of the present invention is to provide an element capable of forming a fine concavo-convex pattern on any basic curved surface (including a flat surface) irrespective of whether the aspherical surface is rotationally symmetric or not. It is intended to obtain a manufacturing method of the. Examples of an element having such a fine concavo-convex pattern include a diffractive lens, a diffractive mirror, a Fresnel lens, a Fresnel mirror, a spectacle lens for correcting astigmatism of a diffractive color correction, a progressive multifocal spectacle lens, a diffractive reflective focusing mirror, and the like. There are optical elements and molds for molding these optical elements.

[0004]

SUMMARY OF THE INVENTION The manufacturing method of the present invention comprises a step of processing a basic curved surface on which a fine uneven pattern is formed on an element material; a mask corresponding to the convex portion of the fine uneven pattern is formed on the processed basic curved surface. Forming a mask; forming a concave portion by removing the basic curved surface of the element material other than the mask; forming a concave portion; and removing a mask remaining on the basic curved surface. I have.

[0005] The mask forming step, the concave part processing step and the mask removing step are performed according to the groove shape of the fine concavo-convex pattern.
It can be executed multiple times with different mask shapes.
Then, in the second and subsequent mask forming steps, a part of the recess formed in the previous recess processing step is masked,
In the next recess processing step, a deeper recess can be formed in the recess.

[0006] The basic curved surface is preferably constituted by a curved surface passing through the tip of each convex portion of the fine concavo-convex pattern. This basic curved surface may be spherical or aspherical, and the fine concavo-convex pattern formed on the basic curved surface may be rotationally symmetric or non-rotationally symmetric. The method of the present invention is more useful when the curved surface is a non-rotationally symmetric aspherical surface and when the fine uneven pattern is non-rotationally symmetric.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 exemplify fine concavo-convex patterns in which the method of the present invention is more useful. FIG. 1 shows a plano-elliptical concentric surface on an aspherical surface (toric surface) 1. FIG. 2 shows an element 3 having a fine concavo-convex pattern (non-rotationally symmetric diffraction pattern) 2, FIG. 2 shows an element 7 having a rectangular rotationally asymmetric fine concavo-convex pattern composed of a short side 5 and a long side 6 on a spherical surface 4, and FIG. An element 9 having a semi-elliptical concentric non-rotationally symmetric fine concavo-convex pattern 8 on a cylinder surface is shown. According to the method of the present invention, a fine uneven pattern can be formed on a basic curved surface irrespective of these forms as long as formation (working) of the basic curved surface is possible.

FIGS. 4 and 5 show examples of a basic curved surface and a processing method thereof. Fig. 4 shows the basic curved surface as the toric surface 1.
This is an example in which the element 11 is set to 0, and a plurality of elements 11 are provided around a holder 13 that is driven to rotate about an axis 12.
The element 11 is polished by applying polishers 14 having different radii of curvature in two orthogonal directions to obtain the toric surface 10. FIG. 5 shows a lathe 1
This is an example of forming a spherical surface or a rotationally symmetric aspherical surface 18 on the element 16 by applying a blade 17 to the element 16 held and rotated in the direction 5 and moving the blade 17 in the radial direction and the direction parallel to the rotation axis.

Next, an example of a method of determining a basic curved surface shape will be described with reference to FIGS. FIG. 6 shows the projection 21 and the depression 2
2 shows an example of a fine uneven pattern having 2 in an alternating manner, in which the depth d is drawn (for example, about 20 times) with respect to the fine uneven pitch p. The actual pitch p is, for example, about 20 μm, and the depth d is about 1 μm. FIG. 7 shows the tip 2 of the projection 21 of this fine uneven pattern.
It is a basic curved surface 23 drawn by connecting 1t.

According to the present invention, the basic curved surface 23 is first formed on the element material (glass, plastic, mold material) 24 by an arbitrary method, and then a fine uneven pattern is formed on the basic curved surface 23. A mask forming step, a concave portion processing step, and a mask removing step, and these steps are repeated a plurality of times as necessary.

FIGS. 8 to 15 show an example of the process. FIG. 8 shows one convex portion 21 from the basic curved surface 23 of FIG.
(Two adjacent tips 21t) are taken out and drawn. The ideal concave portion 22 has a shape that gradually deepens from one tip 21t to the adjacent tip 21t. In this example of the process, the recess 22 is formed by three processes.
This is an example of forming.

On the basic curved surface 23, the adjacent tip 21t
Except for the required length (area) on the deep side of the recess 22 between
First masking (mask) 25 ₁ is performed (FIG. 9). The first masking 25 ₁ is made of a material that does not etch the portion covered by the first masking 25 ₁ when etching the surface of the basic curved surface 23, for example, an aluminum thin film.

[0013] The basic curved surface 23 that the first masking step (mask formation step) is completed by etching to form the first step recess 26 _1. The first etching step in (recess processing step), as the ideal depth first step recess 26 ₁ substantially half the depth of d of the concave portion 22 is formed, defining an etching condition (Fig. 10). As the etching, for example, ion etching, reactive ion etching, or the like can be used.

Next, the remaining first masking 25 ₁
It was removed (the mask removing step) from the second masking step, the first step recess 26 ₁ and again a second masking (mask) to the surface of the basic curved surface 23 subjected to 25 _2. The second masking 25 ₂ is deeper side of the required length of the recess 22 of the first step recess 26 in ₁ (area), the required length subsequent to the first step recess 26 ₁ of the surface of the basic curved surface 23 (region) Except, it is applied (FIG. 11). The basic curved surface 23 that the second masking 25 ₂ is completed, again etched by the second etching step, the second step recess 26 _2, the first step recess 26
₁ and on the surface of the basic curved surface 23. The depth of the second step recess 26 ₂ is about half of the first step recess 26 ₁ (Figure 12).

[0015] In the same manner, after removing the remaining to have a second masking 25 _2, the third masking step, the first step recess 26 _1, the second step recess 26 ₂ and the basic curved surface 2
Again third masking third surface (mask) subjected to 25 _3. Third masking 25 ₃ deep side of the required length of the recess 22 of the first step recess 26 in ₁ (area), the required length of the deep side of the concave portion 22 of the second step recess 26 in ₂ (region) , except the second step recess 26 ₂ followed required length of the surface of the basic curved surface 23 (region), is performed (FIG. 13). The basic curved surface 23 on which the third masking 25 ₃ has been completed is etched again by the third etching step, and the third step recess 26 _{3 is formed.}
The first step recess 26 within ₁ to form the respective surfaces of the second step recess 26 ₂ and inside the basic curved surface 23. The depth of the third step recess 26 ₃ is approximately half of the second step recess 26 ₂ (Figure 14). And finally, the third masking 25 ₃
If removed, the first step recess 26 ₁ of these, the second step recess 26 ₂ and the third step recess 26 _3, the final recess having a shape close to the shape of the recess 22, the ideal is formed (FIG. 15 ).

FIGS. 16 to 22 illustrate the steps from FIG. 10 to FIG. 11 in more detail.
On basic curved surface 23, it shows an example of a specific method of forming the second masking 25 _2.

Now, as shown in FIG.
The element material 24 5 ₁ is attached remaining solution to dissolve the first masking 25 _1, for example, immersed in a NaOH solution, removing the first masking 25 _1. Then, the basic curved surface 23 and element materials 24 to the first step recess 26 ₁ is exposed is obtained (FIG. 16).

The second masking 25 _{2 is} uniformly applied to the exposed basic curved surface 23 and the first process concave portion 26 _{1 of the} element material 24 by an appropriate method such as evaporation or sputtering.
Forming a further, on the second masking 25 _2,
A photoresist (positive type) 28 is uniformly coated (FIGS. 17 and 18).

Next, from above the photoresist 28,
A portion where a groove is to be formed is selected and exposed. Exposure is performed by using a condenser lens 29 and the basic curved surface 23 and the first process concave portion 2.
Scanning is performed on the non-masking sections (areas) e ₁ and e ₂ on the pixel 6 ₁ . This exposure section (area) corresponds to the second section in FIG.
Corresponds to the section (region) that do not form masking 25 ₂ (Figure 19). At the time of this scanning exposure, a required relative movement is given to the element material 24 and the condenser lens 29 according to the shapes of the convex portions 21 and the concave portions 22.

When the photoresist 28 of the element material 24 after the exposure is developed (resist development) with a developing solution (solvent), the photoresist 28 in the exposure section (region) is developed.
Is removed (FIG. 20). Thus, then if Hodokose the etching of the mask material, a second masking 25 a _second portion photoresist 28 is removed is removed (FIG. 21)
From then by removing the photoresist 28 remaining, as shown in FIG. 22, the required length of the first step recess 26 in ₁ (region), the first step recess 26 on the surface of the basic curved surface 23
Only a portion excluding the required length followed by ₁ (the region), the second masking 25 ₂ is performed (FIG. 22). This state is the same as FIG.

[0021] above, but the second masking 25 ₂ illustrates an example of creation process example, the first masking 2
5 _1, it is possible to create a third masking 25 ₃ also quite similarly.

FIGS. 23 to 25 show another exposure method which is an alternative to the exposure method of FIG. In FIG. 19, the non-masking sections (areas) e ₁ and e ₁
And scanning exposure to _2, but 23 to 25 are those by the contact exposure, simultaneously exposed unmasked section (region) e ₁ and e _2. FIG. 23 corresponds to FIG.
A mask 32 that does not transmit light is formed on the unmasked mask glass 31 corresponding to the non-exposed portion. The mask glass 31 and the element material 24 are aligned and overlapped with each other, and a contact exposure light beam 33 is given, so that a non-masking section (region) of the photoresist 28 is provided as in FIG.
Only e ₁ and e ₂ can be exposed.

FIG. 24 shows a case of forming the third masking 25 _3. Pattern of the mask 32 to form the mask glass 31 corresponds to the third masking 25 ₃ in FIG. 13.

FIG. 25 shows an example of a configuration for correctly aligning and overlaying a plurality of mask glasses 31 having different masks 32 on the same element material 24. Element material 2
4 is fixed to a base 36 having a tapered surface 36a around it, and the mask glass 31 has a base frame 3 having a tapered surface 37a that matches the base tapered surface 36a of the base 36.
7 is fixed at a predetermined position. The mask glasses 31 having different masks 32 are respectively fixed to a plurality of underframes 37 having the same shape. According to this configuration, the underframe 37
Are alternately overlapped on the base 36 and are exposed in close contact with the element material 24 (the upper photoresist 28), so that the first masking 25 ₁ ,
The second masking 25 ₂ and the third masking 25 ₃ can be formed.

[0025]

According to the present invention, elements such as lenses, mirrors, molding dies and the like having a fine concavo-convex pattern can be used regardless of whether the basic curved surface is spherical or aspherical, and whether the fine concavo-convex pattern is rotationally symmetric or asymmetric. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a three-view drawing showing an example of an element having a fine concavo-convex pattern.

FIG. 2 is a three-view drawing showing another example of an element having a fine concavo-convex pattern.

FIG. 3 is a three-view drawing showing another example of an element having a fine concavo-convex pattern.

FIG. 4 is a diagram illustrating an example of a basic curved surface and a method of creating the same.

FIG. 5 is a diagram showing another example of a basic curved surface and a method of creating the same.

FIG. 6 is a cross-sectional view showing a specific example of a fine concavo-convex pattern in which concavities and convexities are enlarged.

7 is a cross-sectional view showing a basic curved surface shape determined based on the fine concavo-convex pattern of FIG.

FIG. 8 is a diagram showing one of the fine concavo-convex patterns to be formed on the basic curved surface of FIGS.

FIG. 9 is a view showing a state of a mask applied in a first masking step on the basic curved surface of FIG. 8;

FIG. 10 is a view showing a state in which a material subjected to a first masking step in FIG. 9 is subjected to a first etching step and processed to form a groove.

FIG. 11 is a view showing a state of a mask formed in a second masking step after the first etching step in FIG. 10;

FIG. 12 is a diagram showing a state in which a material subjected to a second masking step in FIG. 11 is subjected to a second etching step to form grooves.

FIG. 13 is a view showing a state of a mask formed in a third masking step after the second etching step in FIG. 12;

FIG. 14 is a view showing a state in which the material subjected to the third masking step in FIG. 13 is subjected to a third etching step to form a groove.

FIG. 15 is a view showing a groove shape after final processing, in which a mask has been removed from the state of FIG. 14;

FIG. 16 is a view showing a state after the first mask removing step is completed, showing a state in which a residual mask is removed from a state after the first etching step in FIG. 10 is completed.

17 is a view showing a state in which a new mask is applied to the entire surface of the material in the state of FIG. 16;

18 is a view showing a state in which a photoresist is applied to the entire surface of the mask in the state of FIG. 17;

19 is a view showing a state in which a groove forming portion on the photoresist in the state of FIG. 18 is exposed.

FIG. 20 is a view showing a state in which the photoresist at the exposed portion in FIG. 19 has been removed.

21 is a diagram showing a state in which the exposed mask of FIG. 20 has been removed by mask material etching.

FIG. 22 is a diagram showing a state (same state as in FIG. 11) in which the photoresist in an unexposed portion in FIG. 20 has been removed;

FIG. 23 is a view showing a state in which a groove forming portion on the photoresist in the state of FIG. 18 is exposed by close contact exposure.

24 is a diagram showing a state in which contact exposure is performed again in the next step after the state shown in FIG. 23;

FIG. 25 is a diagram showing a specific example of a mask used in the contact exposure in FIGS. 23 and 24;

[Explanation of symbols]

Reference Signs List 21 convex portion 21t convex portion tip 22 concave portion 23 basic curved surface 24 element material 25 ₁ 25 ₂ 25 ₃ masking (mask) 26 ₁ 26 ₂ 26 ₃ concave portion 28 photoresist 29 condensing lens 31 mask glass 32 mask 33 contact exposure light flux

Claims (6)

[Claims] 1. A step of processing a basic curved surface on which a fine uneven pattern is formed on an element material; a mask forming step of forming a mask corresponding to the convex portion of the fine uneven pattern on the processed basic curved surface; An element having a fine concavo-convex pattern, comprising: a recess processing step of removing a basic curved surface of the element material other than the mask to form a concave portion; and a mask removing step of removing a mask remaining on the basic curved surface. Manufacturing method. 2. The manufacturing method according to claim 1, wherein the mask forming step, the concave portion processing step, and the mask removing step include:
A method for manufacturing an element having a fine concavo-convex pattern that is performed a plurality of times with different mask shapes. 3. The manufacturing method according to claim 2, wherein in the second and subsequent mask forming steps, a part of the recess formed in the previous recess processing step is masked, and in the next recess processing step, A method for manufacturing an element having a fine uneven pattern for forming a deeper recess in the recess. 4. The method according to claim 1, wherein the basic curved surface has a fine concavo-convex pattern that is a curved surface passing through a tip of each convex portion of the fine concavo-convex pattern. 5. The method according to claim 4, wherein the basic curved surface has an aspherical fine concavo-convex pattern. 6. The method according to claim 5, wherein the aspherical surface forming the basic curved surface is a non-rotationally symmetric aspherical surface and has a fine uneven pattern.