JP2021167849A - Manufacturing method of metal mask and the metal mask, and manufacturing method of high-aspect diffraction grating and the high-aspect diffraction grating - Google Patents

Abstract

To provide a manufacturing method of a metal mask having resistance in etching and the metal mask obtained by the method, and to provide a manufacturing method of a high-aspect diffraction grating having high resolution and using the metal mask and the high-aspect diffraction grating obtained by the method.SOLUTION: A manufacturing method of a metal mask comprises: forming an aluminum layer on a silicon substrate; patterning the aluminum layer; forming a grating with a rugged structure by etching the silicon substrate corresponding to an area where the aluminum layer is removed; forming an etching resist by filling a recess of the grating with an organic material and solidifying it; removing the organic material while leaving it in a bottom part of the recess; applying metal plating to an upper surface part and a side surface part where the organic material has been removed; and manufacturing the metal mask by removing the organic material left in the bottom part of the recess.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a metal mask used for manufacturing a diffraction grating and the like, a method for manufacturing a high-aspect diffraction grating that can be suitably used for a Talbot interferometer and a Talbot-low interferometer, and a high-aspect diffraction grating. Regarding.

Diffraction gratings are used in the optical systems of various devices as spectroscopic elements having a large number of parallel periodic structures, and in recent years, applications to X-ray imaging devices have also been attempted. Diffraction gratings are classified into transmission type diffraction gratings and reflection type diffraction gratings according to the diffraction method. Further, in the transmission type diffraction grating, parts that absorb light are periodically arranged on a substrate that transmits light. There are an amplitude type diffraction grating (absorption type diffraction grating) and a phase type diffraction grating in which portions that change the phase of light are periodically arranged on a substrate that transmits light.

On the other hand, X-rays are generally absorbed very little by substances and their phase changes are not so large. Even when a diffraction grating for X-rays is made of gold (Au), which has a relatively large X-ray absorption capacity, the thickness of the gold needs to be about 100 μm, and the transmission portion and the absorption or phase change portion have the same width. When the periodic structure is formed at a pitch of several μ to several tens of μ, the ratio of the thickness to the width of the gold portion (aspect ratio = thickness / width) is a high aspect ratio of 5 or more. It is technically difficult to stably manufacture such a structure having a high aspect ratio.

Therefore, a method for manufacturing a diffraction grating having such a structure having a high aspect ratio is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-037023. The method for manufacturing a diffraction grating disclosed in the above patent document is a method for manufacturing a diffraction grating used for an X-ray Talbot interferometer, but in the method for manufacturing the diffraction grating, until the X-ray absorbing metal portion has a required thickness. Many steps were required, the productivity was poor, the aspect was low, and the performance as a diffraction grating was insufficient.

The G0 diffraction grating (also called a multi-slit) applied to the current diffraction grating for X-ray Talbot plays a role of producing coherent X-rays having interference ability, and is a key device that influences the S / N ratio of an image. Is. This diffraction grating constitutes an X-ray blocking portion by filling a silicon substrate that transmits X-rays and a concave portion (slit portion) having a concave-convex structure with a metal component, for example, gold. In the X-ray imaging apparatus, contrast is obtained by recording the intensity of X-rays transmitted through the imaging target as they are. However, in order to obtain a higher resolution image, it is necessary to further increase the applied voltage, but when the voltage becomes high, X-rays are formed in the low aspect recess formed by the metal component having a predetermined depth. Starts to pass through, the coherence capability decreases, and the S / N ratio deteriorates, so that a clear image with high contrast cannot be obtained.

Therefore, studies are underway to manufacture a diffraction grating using a metal grating with a high aspect ratio by utilizing the characteristics of silicon capable of forming a three-dimensional structure. That is, a slit groove having a periodic structure with a high aspect ratio is formed on a silicon substrate, and by utilizing the conductivity of silicon in the formed slit groove, a metal is embedded by an electroplating method (electrocasting method) to form a diffraction grating. A manufacturing method is conceivable.

For example, a method of forming a recess while etching using a mask, and a method of repeatedly forming a protective film on the side surface of the formed recess and etching to form a microstructure are disclosed (for example, a patent). See Reference 1.). However, in the method disclosed in Patent Document 1, for example, when an attempt is made to produce a diffraction grating having a concave-convex structure having a high aspect ratio such that the depth of the recess exceeds 300 μm, as deep digging is performed, the diffraction grating is directly under the mask. The already formed lattice portion of the above was damaged by etching, the shape of the tip was disturbed, and it was difficult to form a concavo-convex structure having a stable shape and a high aspect ratio exceeding 300 μm.

Japanese Patent No. 5353101

The present invention has been made in view of the above problems, and the problem to be solved thereof is mainly a method for producing a metal mask which is suitable for producing a high-aspect diffraction grating and has resistance to etching, and a method for producing the same. A method for producing a high-resolution high-aspect diffraction grating that can be suitably used for, for example, a Talbot interferometer or a Talbot-low interferometer, and a high aspect obtained by the metal mask. It is to provide a diffraction grating.

As a result of diligent studies in view of the above problems, the present inventor has formed a lattice having a concavo-convex structure on the silicon substrate, filled the recesses of the lattice with an organic material and solidified it to form an etching resist, and formed the organic. A metal for producing a metal mask by removing the material leaving the bottom of the recess, metal-plating the upper surface and the side surface from which the organic material has been removed, and removing the organic material left at the bottom of the recess. We have found that we can provide a method for manufacturing a mask, and have arrived at the present invention.

That is, the above problem according to the present invention is solved by the following means.

1. 1. A method for manufacturing a metal mask using a silicon substrate.
The first step of forming an aluminum layer on the silicon substrate and
After applying the resist on the aluminum layer, the resist is patterned, and then the aluminum layer is patterned in the second step.
A third step of etching the silicon substrate corresponding to the region from which the aluminum layer has been removed to form a lattice having an uneven structure, and
The fourth step of filling the recesses of the lattice with an organic material and solidifying it to form an etching resist.
The fifth step of removing the organic material by an etching method, leaving the bottom of the recess, and
The sixth step of applying metal plating to the upper surface portion and the side surface portion from which the organic material has been removed, and
A seventh step of removing the organic material left on the bottom of the recess,
A method for manufacturing a metal mask, which comprises manufacturing a metal mask through the process.

2. The first item is characterized in that the silicon substrate having the concavo-convex structure has a concavo-convex structure in which the groove width is in the range of 1 to 50 μm and the groove depth of the recess is in the range of 1 to 150 μm. The method for manufacturing a metal mask according to the description.

3. 3. The method for producing a metal mask according to item 1 or 2, wherein the organic material is removed by treatment with acetone or oxygen plasma.

4. A metal mask using a silicon substrate
The silicon substrate has a lattice having a concavo-convex structure, and
A metal mask characterized in that metal plating is applied to a side surface portion excluding the upper surface portion and the bottom portion of the convex portion of the concave-convex structure.

5. A method for manufacturing a high-aspect diffraction grating using the metal mask according to the fourth item.
An etching step of digging a concave portion of a silicon substrate of the metal mask having an uneven structure to a predetermined depth, and
A step of forming an insulating layer on the surface portion and the concave surface of the deeply dug silicon substrate on the side having the uneven structure, and
A step of removing the insulating layer formed on the bottom of the recess, and
A method for manufacturing a high-aspect diffraction grating, which comprises an electroforming step of filling the recesses with metal by an electroforming method.

6. The method for manufacturing a high-aspect diffraction grating according to item 5, wherein the metal used in the electroforming step is gold.

7. A high-aspect diffraction grating using the metal mask according to the fourth item.
A high-aspect diffraction grating characterized in that a lattice having a concavo-convex structure has a concavo-convex structure in which the tip portion is metal-plated and the depth of the groove of the recess is in the range of 300 to 500 μm.

By the above means of the present invention, a method for producing a metal mask suitable for producing a high-aspect diffraction grating and having resistance at the time of etching, a metal mask obtained by the method, and using the metal mask, for example, Talbot interference. It is possible to provide a method for producing a high-resolution high-aspect diffraction grating that can be suitably used for a meter or a Talbot-low interferometer, and a high-aspect diffraction grating obtained thereby.

Although the mechanism of expression and mechanism of action of the effects of the present invention have not been clarified, it is inferred as follows.

In the method for producing a metal mask of the present invention,
1) The first step of forming an aluminum layer on the silicon substrate and
2) A second step of coating the resist on the aluminum layer, patterning the resist, and then patterning the aluminum layer.
3) A third step of etching the silicon substrate corresponding to the region from which the aluminum layer has been removed to form a lattice having a concavo-convex structure.
4) The fourth step of filling the recesses of the lattice with an organic material and solidifying it to form an etching resist.
5) The fifth step of removing the organic material by an etching method, leaving the bottom of the recess, and
6) The sixth step of applying metal plating to the upper surface portion and the side surface portion from which the organic material has been removed, and
7) A seventh step of removing the organic material left on the bottom of the recess,
By manufacturing the metal mask through the above, it is possible to reduce damage to the upper surface portion and the convex portion side surface portion of the silicon substrate on which the metal mask is formed during etching.

Further, using the microstructure having this metal mask, the tip of the convex portion is protected by the metal mask, especially when manufacturing a high-aspect diffraction grating, during deep digging, and even during a long-term etching step. It was possible to obtain a diffraction grating in a state, without being damaged, having a stable shape, and having a high aspect, for example, a structure in which the depth of the recess exceeds 300 μm.

Schematic cross-sectional view showing an example of the overall configuration of the metal mask provided with the metal plating of the present invention. Schematic diagram showing an example of a manufacturing process of a metal mask provided with metal plating (No. 1) Schematic diagram showing an example of a manufacturing process of a metal mask provided with metal plating (Part 2) Schematic diagram showing an example of a method for forming a metal mask by an electroforming method Schematic diagram showing an example of a manufacturing process of a high-aspect diffraction grating using the metal mask of the present invention (No. 1) Schematic diagram showing an example of a manufacturing process of a high-aspect diffraction grating using the metal mask of the present invention (Part 2). Schematic cross-sectional view showing an example of the overall configuration of the high-aspect diffraction grating of the present invention. Schematic perspective view showing an example of the overall configuration of the high-aspect diffraction grating of the present invention. Conceptual diagram showing an example of the lattice structure of a high-aspect diffraction grating by deep etching Schematic configuration diagram showing an example of the configuration of a Talbot-Lago interference meter for X-rays to which the high-aspect diffraction grating of the present invention is applied.

The method for manufacturing a metal mask of the present invention is a method for manufacturing a metal mask using a silicon substrate, which is a first step of forming an aluminum layer on the silicon substrate and after applying a resist on the aluminum layer. A second step of patterning the resist and then patterning the aluminum layer, and a third step of etching the silicon substrate corresponding to the region from which the aluminum layer has been removed to form a lattice having a concavo-convex structure. The fourth step of filling the recesses of the lattice with an organic material and solidifying it to form an etching resist, the fifth step of removing the organic material by an etching method leaving the bottom of the recesses, and the removal of the organic material. It is characterized in that a metal mask is manufactured through a sixth step of applying metal plating to the upper surface portion and the side surface portion and a seventh step of removing the organic material left on the bottom portion of the recess. This feature is a technical feature common to or corresponding to the invention according to each of the following embodiments.

In the embodiment of the present invention, from the viewpoint that the effect intended by the present invention can be more exhibited, the silicon substrate having the uneven structure has a groove width in the range of 1 to 50 μm and a groove depth of the recess. It is preferable to have a metal-plated portion having a concavo-convex structure in the range of 1 to 150 μm in that a high-aspect diffraction grating can be stably manufactured.

Further, applying an organic material as an etching resist formed by filling the concave portion of a metal mask can be easily removed by acetone or oxygen plasma treatment without damaging the silicon substrate constituting the lattice (convex portion). It is preferable in that it can be used.

Further, in the method for manufacturing a high-aspect diffraction lattice of the present invention, the metal mask of the present invention is used, and an etching step of deeply digging a recess of a silicon substrate of a metal mask having a concavo-convex structure to a predetermined depth and a deep digging are performed. A step of forming an insulating layer on the surface portion of the silicon substrate having an uneven structure and a surface of the recessed portion, a step of removing the insulating layer formed on the bottom portion of the recessed portion, and a metal casting method on the recessed portion. It is characterized in that a high-aspect diffraction lattice is manufactured through an electrocasting process of filling the metal. According to the method for producing a high-aspect diffraction grating of the present invention, it is possible to form an X-ray blocking portion having a recess having a groove depth of 300 μm or more and having a metal component having a sufficient thickness, preferably gold. A high-aspect diffraction grating with high resolution can be obtained.

In the present invention, in the uneven structure formed on the silicon substrate, the portion forming the lattice is also referred to as a convex portion, a silicon layer or a lattice portion. The recess is also referred to as a groove or a slit (slit groove).

Further, in the present invention, the uneven structure in which the upper surface portion and the side surface portion (excluding the bottom portion) are metal-plated is referred to as a metal mask, and in some cases, a precursor for forming a diffraction grating.

Further, using the metal mask of the present invention, deep etching is performed on the recesses to form recesses having a desired depth, which is called a high-aspect diffraction grating.

Hereinafter, the present invention, its constituent components, and modes and modes for carrying out the present invention will be described in detail with reference to the drawings. In the following description, "~" is used to mean that the numerical values described before and after it are included as the lower limit value and the upper limit value. Further, in the following description, the numbers in parentheses after each component represent the code of each component described in each figure.

《Metal mask》
As a first step, the details of the metal mask, which is a precursor used for forming the high-aspect diffraction grating, will be described.

The metal mask of the present invention
1) The first step of forming an aluminum layer on a silicon substrate,
2) A second step of coating the resist on the aluminum layer, patterning the resist, and then patterning the aluminum layer.
3) A third step of etching the silicon substrate corresponding to the region from which the aluminum layer has been removed to form a lattice having a concavo-convex structure.
4) The fourth step of filling the recesses of the lattice with an organic material and solidifying it to form an etching resist.
5) The fifth step of removing the organic material by an etching method, leaving the bottom of the recess, and
6) The sixth step of applying metal plating to the upper surface portion and the side surface portion from which the organic material has been removed, and
7) A seventh step of removing the organic material left on the bottom of the recess,
Manufactured through.

Further, the metal mask is composed of a silicon substrate having a metal plating on the upper surface portion and the side surface portion and having a concavo-convex structure, the groove width is within the range of 1 to 50 μm, and the groove depth of the recess is 1 to 1. It has an uneven structure within the range of 150 μm.

[Basic structure of metal mask]
FIG. 1 is a schematic cross-sectional view showing an example of the overall configuration of the metal mask provided with the metal plating of the present invention.

As shown in FIG. 1, the metal mask (1) of the present invention is composed of a plurality of convex portions (5) and concave portions (4) on the upper portion of the silicon substrate (3).

An aluminum layer (2) used for forming the concave portion (4) is formed on the upper portion of the convex portion (5). Features of the metal mask of the present invention, the upper surface metal plating portions on the upper surface of the protrusion (5) (M _T) is formed, the side surface metal plating portions of the convex portions in a region excluding the bottom portion of the side surface portion (6) ( M _S) is formed. However, the feature is that there is no metal plating on the bottom.

In the metal mask (1), the groove width (W1) of the recess is preferably in the range of 1 to 50 μm, and the groove depth (d1) of the recess is preferably in the range of 1 to 150 μm.

[Components and manufacturing method of metal mask]
2 and 3 are schematic views showing an example of a manufacturing process of a metal mask provided with metal plating, and the details of the method for manufacturing a metal mask will be described with reference to the drawings.

(Preparation of silicon substrate)
It is preferable to use P-type silicon as the silicon substrate used for producing the metal mask of the present invention. By using P-type silicon, it is suitable for forming a metal component of a diffraction grating in a recess by applying an electroforming method.

(Formation of aluminum layer: 1st step)
Next, as a first step, as shown in FIG. 2A, an aluminum layer (2) is formed on the silicon substrate (3).

The aluminum layer (2) functions as a mask member when forming a recess by etching at a specific position on the silicon substrate in the next step, and is a material having resistance to the etching process in the etching step. Consists of.

In the present invention, the aluminum layer (2) is formed on the silicon substrate (3). Specifically, the film is formed by a film forming method such as a vacuum vapor deposition method or a sputtering method. Further, reactive ion etching (hereinafter, abbreviated as RIE) using an appropriate reactive gas is used for patterning the aluminum layer in the patterning step. For example, an aluminum film is formed on an aluminum layer at about 150 nm by a sputtering method, and the aluminum film is patterned by RIE using chlorine gas.

(Etching of silicon substrate: 3rd process)
After patterning the aluminum layer, a concavo-convex structure having the configuration shown in FIG. 2 (c) is formed in a region where the aluminum layer is not formed by a dry etching method.

The silicon substrate (3) in the region from which the resist layer and the aluminum layer (2) have been removed is etched by the dry etching method to a predetermined depth using the etching apparatus (E). As a result, the recess (4) of the metal mask is formed.

Specifically, the aluminum layer (3) is formed on the silicon substrate (3). Next, the resist is applied onto the aluminum layer (3) by a spin coating method or the like, and then the resist is patterned into a slit shape (L / S shape) having a predetermined width by using an electron beam drawing apparatus (EB drawing). .. Next, the aluminum layer is patterned (etched) using the patterned resist as a mask. For etching the aluminum layer, for example, an Al etchant manufactured by Kanto Chemical Co., Inc. can be used.

As the resist, a positive photoresist or a negative photoresist can be used. Known materials can be used as the positive photoresist and the negative photoresist. For example, as the negative photoresist, ZPN-1150-90 manufactured by Zeon Corporation can be used. Further, as the positive type photoresist, OEBR-CAP112PM manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used.

Using the patterned photoresist layer and aluminum layer (2) as a mask, the silicon substrate (3) is etched by ICP (Inductively Coupled Plasma) dry etching from the surface of the silicon substrate (3) to a predetermined depth H, and a recess is formed. (4) is formed. The shape of the recess is preferably a concavo-convex structure in which the groove width is in the range of 1 to 50 μm and the groove depth of the recess is in the range of 1 to 150 μm. The photoresist layer is removed by this ICP dry etching. At this time, the aluminum layer (2) may be slightly etched.

The thickness of the aluminum layer (2) is reduced by ICP dry etching, for example, from about 150 nm to about 130 nm.

This ICP dry etching is preferably an ASE process using an ICP apparatus because it can perform vertical etching with a high aspect ratio. This ASE (Advanced Silicon Etch) process is a step of etching a silicon substrate by RIE (reactive ion etching) with F radicals and F ions _{in SF 6} plasma, and _{CF x radicals in C 4} F ₈ plasma. By the polymerization reaction of these ions, a step of depositing a polymer film having a composition close to Teflon (registered trademark) on the wall surface and acting as a protective film is repeated. In addition, since more vertical etching can be performed with a high aspect ratio, more preferably, the SF ₆ plasma rich state and the C ₄ F ₈ plasma rich state are alternately repeated as in the Bosch process. As a result, side wall protection and bottom etching may be allowed to proceed alternately. The dry etching method is not limited to ICP dry etching, and may be another method. For example, etchings such as so-called parallel plate type reactive ion etching (RIE), magnetic neutral ray plasma (NLD) dry etching, chemically assisted ion beam (CAIB) etching and electron cyclotron resonance type reactive ion beam (ECRIB) etching. It may be a technology.

(Filling of organic material in the recess: 4th step)
Next, the recess formed in the third step is filled with an organic material as shown in FIG. 2 (d).

The organic material (7) for forming the etching resist by filling the recesses is not particularly limited, but the organic material shown below is preferable.

Examples of the organic material applicable to the present invention include quinone diazides such as naphthoquinone diazide and benzoquinone diazide, diazo compounds such as diazomethyldrum acid, diazodimedone, 3-diazo-2,4-dione, and o-nitrobenzyl ester. , Onium salt, photodegrading agent (dissolution inhibitor) such as a mixture of onium salt and polyphthalaldehyde, t-butyl cholineate, and hydroquinone, fluoroglucosin, 2,3,4-, which has an OH group and is soluble in alkali. A mixture of monomers such as trihydroxybenzophenone, novolak resins such as phenol novolac resin and cresol novolac resin, copolymers of styrene and maleic acid and maleimide, and polymers of phenolic and methacrylic acid, styrene and acrylonitrile copolymers. Condensates, or polymethylmethacrylate, polymethylmethacrylate, polyhexafluorobutyl methacrylate, dimethyltetrafluoropropyl methacrylate, trichloroethyl polymethacrylate, methyl-acrylic nitrile copolymer, polymethylisopropenylketone, Examples thereof include poly α-cyanoacrylate and polytrifluoroethyl-α-chloroacrylate. Among these, a mixed / condensate containing novolak resin as a main component is preferably used from the viewpoint of versatility.

In addition, these organic materials are also available as commercial products, for example, those in the semiconductor coating material "Sumiresin Excel CRC-8000" series manufactured by Sumitomo Bakelite, specifically, for example, CRC-8200, CRC. -8300 can be used. Further, OFPR-800, TSMR-V90, TMMR S2000, PMER-900 and the like manufactured by Tokyo Ohka Kogyo can be used. Those in the "ELPAC WPR series" manufactured by JSR, specifically, for example, WPR-1020 can be used. The "ZPP2400, ZPP2500, ZPP2600, ZPP2700 series" of the positive type photoresist "ZEONREX" for TFT manufacturing, which is in the positive type insulating film "ZEONCOAT series" manufactured by ZEON Corporation can be used. The "NPR9000, 7800, 8000 series" manufactured by Nagase ChemteX can be used. "TFP600 series" manufactured by AZ Electronic Materials, specifically, for example, TFP-650F5, TFP-650H2, "AZ SR series", specifically, for example, AZ SR-100, AZ SR-110. , AZ SR-210, "AZ SFP series", specifically, for example, AZ SFP -1400 and AZ SFP -1500 can be used.

In the present invention, as a solvent applicable to the preparation of the recess filling liquid using an organic material, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, dimethyl formamide, etc. Examples thereof include dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone and the like. These solvents are used alone or in admixture of two or more.

As a method for filling the recesses with the organic material (7), a coating liquid prepared with the above organic material, a solvent, or the like is appropriately selected from a conventionally known wet coating method, and is formed into a slit shape by utilizing a capillary phenomenon or the like. It can be formed by filling the recesses of the above, heating and drying under desired conditions.

(Removal of organic material in the area other than the bottom: 5th step)
Next, in the fourth step, of the organic material (7) filled in the concave portion (4), as shown by FIG. 3 (a), the organic material (8) at the bottom is removed.

The method for removing the organic material leaving the bottom portion is not particularly limited, but it is preferable to remove the organic material by treatment with acetone or oxygen plasma.

As a method for removing the organic material using acetone, a method of immersing the silicon base material (3) filled with the organic material in an acetone solution for a predetermined time, or a predetermined method while supplying acetone from the surface of the silicon base material. A method of removing the organic material to the depth of the above can be mentioned.

Further, as the oxygen plasma treatment, the following methods can be mentioned.

As shown in FIG. 3 (a), the oxygen plasma (10) having a strong oxidizing power for organic substances is formed in the recesses from the oxygen plasma device (9) arranged on the silicon base material (3). The material is irradiated to decompose and remove other organic materials, leaving the organic material (8) at the bottom. Specifically, the surface of an organic material is irradiated with oxygen (oxygen radical) in a high energy state, bonded to carbon constituting the organic material, and vaporized and decomposed (carbonized, ashed) as _{CO 2.} By continuously performing this, the organic material can be cut to a predetermined depth.

As the gas used for the oxygen plasma treatment, a single gas or a mixed gas that generates oxygen plasma is used as the main component. As the single gas, for example, an oxygen atom-containing gas such as oxygen, carbon monoxide, and carbon dioxide can be used, while as the mixed gas, helium, nitrogen, argon, as long as the generation of oxygen plasma is not suppressed. A known and commonly used gas such as an inert gas such as, chlorine-based gas, fluorine-based gas, hydrogen gas, and ammonia gas may be appropriately mixed.

The thickness of the organic material remaining on the bottom (6) is not particularly limited, but is preferably in the range of 10 to 50% of the depth of the groove of the recess, and more preferably in the range of 15 to 30%. Inside.

(Applying metal plating to the upper surface and side surfaces: 6th step)
Next, the upper surface portion and the side surface portion excluding the upper surface portion and the bottom portion of the convex portion (5) constituting the silicon base material (3) formed according to the above method are subjected to metal plating treatment, and as shown in FIG. 3 (b), the upper surface portion is subjected to metal plating treatment. metal plating unit _{(M T)} and the side surface metal plating unit _{(M S)} is formed.

It is preferable to apply an electroplating method (electroplating method) to the formation of the metal plating layer.

FIG. 4 is a schematic view showing an example of a method for forming a metal mask by an electroforming method applicable to the present invention.

As shown in Figure 4, by electroforming (electroplating), by applying a voltage to the silicon substrate (3), to form the upper surface metal plating unit (M _T) and the side surface metal plating layer (M _S). More specifically, the cathode of the power supply (13) is connected to the silicon substrate (3), and the anode electrode (12) and the silicon substrate (3) connected to the anode of the power supply (13) are used as the plating solution (11). Soaked. At this time, in order to ensure that the plating solution (11) is permeated through the recesses (4), the surface of the silicon base material (3) is made hydrophilic by a method such as alkali treatment, or the silicon base material is made into the plating liquid (11). The air in the recess (4) is evacuated by applying ultrasonic vibration while the (3) is immersed or by putting the plating solution (11) and the silicon base material (3) in a vacuum chamber, and the plating solution in this state. Treatments such as immersing in (11) or evacuating the silicon base material (3) in the plating solution (11) to evacuate the air in the recess (4) may be performed. ..

In the present invention, the metals used for metal plating include, for example, gold (Au), platinum (platinum, Pt), rhodium (Rh), ruthenium (Ru), iridium (Ir), indium (In) and nickel (Ni). Etc., preferably nickel (Ni).

The thickness of the metal-plated portion is not particularly limited, but is generally in the range of 10 to 500 nm, preferably in the range of 100 to 300 nm.

(Removal of organic material at the bottom: 7th step)
Finally, as shown in FIG. 3C, the organic material (8) remaining on the bottom is removed to prepare a metal mask.

As a method for removing the organic material at the bottom used in the seventh step, it can be removed by the acetone or oxygen plasma treatment used in the fifth step shown in FIG. 3 (a), or by using the two methods in combination. For example, after peeling off the organic material remaining on the bottom using acetone, oxygen ashing by oxygen plasma treatment is further performed to perform a cleaning treatment for completely removing the residue of the organic material on the bottom.

As described above, the metal mask (1) having metal plating is produced on the side surface portions excluding the upper surface portion and the bottom portion of the convex portion.

《High aspect diffraction grating》
Then, as a second step, a high-aspect diffraction grating is produced using the produced metal mask.

The present invention is characterized in that a high-aspect diffraction grating is produced according to the following steps.

1) An etching process in which a concave portion of a silicon substrate of the metal mask having an uneven structure is deeply dug to a predetermined depth.
2) A step of forming an insulating layer on the surface portion and the concave surface of the silicon substrate on the side having the uneven structure, which is dug deeply.
3) A step of removing the insulating layer formed on the bottom of the recess, and
4) An electroforming process in which the recess is filled with a metal component by an electroforming method.

The details of each step will be described below.

(Preparation of metal mask)
First, as shown in FIG. 5 (a), to prepare the upper surface metal plating portions on the convex portion was manufactured (M _T) and the side surface metal plating unit (M _S) of the formed metal mask (1) in the process.

(Deep etching process)
Next, deep etching is performed on the recess (4) of the metal mask (1) using the etching apparatus (E). As a result, a high-aspect deep-drilled recess (4B) is formed.

As the etching method, the method described when etching the silicon substrate shown in FIG. 2 (c), which is the third step of the metal mask (1), can be applied.

Specifically, the silicon substrate (3) is further deeply etched and deeply etched by ICP (Inductively Coupled Plasma) dry etching, which is an etching apparatus (E), from the surface of the silicon substrate (3) to a predetermined depth H. A digging recess (4B) is formed. The shape of the deep-drilled recess (4B) is preferably such that the groove width is within the range of 1 to 50 μm, but the depth of the groove of the deep-drilled recess is within the range of 300 to 500 μm, and further. It is preferably in the range of 300 to 500 μm.

This ICP dry etching is preferably an ASE process using an ICP apparatus because it can perform vertical etching with a high aspect ratio. This ASE (Advanced Silicon Etch) process is a step of etching a silicon substrate by RIE (reactive ion etching) with F radicals and F ions _{in SF 6} plasma, and _{CF x radicals in C 4} F ₈ plasma. By the polymerization reaction of these ions, a step of depositing a polymer film having a composition close to Teflon (registered trademark) on the wall surface and acting as a protective film is repeated. Furthermore, since more vertical etching can be performed with a high aspect ratio, it is particularly preferable that the SF ₆ plasma is rich and the C ₄ F ₈ plasma is rich, as in the Bosch process. A method of alternately proceeding the side wall protection and the bottom etching by repeating is preferable. The dry etching method is not limited to ICP dry etching, and may be another method. For example, etchings such as so-called parallel plate type reactive ion etching (RIE), magnetic neutral ray plasma (NLD) dry etching, chemically assisted ion beam (CAIB) etching, and electron cyclotron resonance type reactive ion beam (ECRIB) etching. It may be a technology.

(Aluminum layer and metal plating peeling process)
Then, as shown in FIG. 5 (c), peeled aluminum layer is a mask member during etching and (2) metal plating (M _{T, M S)} of. As a peeling method, the deeply dug high-aspect uneven structure prepared above is subjected to chlorine etching treatment by a plasma etching apparatus (E2) using a mixed gas of _{chlorine (Cl 2} ) and boron trichloride (BCl _3). Te, peeled aluminum layer formed on the convex upper surface and (3), metal plating _(M T, _{M S)} of.

(Insulation layer forming process)
Next, as shown in FIG. 6A, an insulating layer is formed on the surface portion and the concave surface of the silicon base material (3) on the side having the uneven structure. Specifically, the upper surface insulating layer (17T) is provided on the upper surface of the convex portion (5) of the concave-convex structure formed on the silicon substrate (3), and the side surface insulating layer (17S) is provided on the side surface of the convex portion (5). A bottom insulating layer (17B) is formed on the bottom of the recess, and an insulating layer (17) is formed on the periphery of the silicon substrate (3), if necessary. This insulating layer plays a role of controlling so that unnecessary plating growth does not occur in the metal plating step (electroplating step) of forming a metal component, for example, an X-ray shielding portion in the recess in a subsequent step.

As a method for forming the insulating layer, a thermal oxidation method, an anodizing method, a CVD method, a sputtering method, a vapor deposition method and the like can be applied.

<Formation of insulating layer by thermal oxidation method>
A predetermined thickness of the silicon substrate (3) so as to have insulating properties against the electroforming method of the electroforming process of forming a metal component described later by a thermal oxidation method on the entire inner surface of the upper surface portion and the concave portion (4B). Insulation layer (17) is formed. Since the insulating layer (17) uses the silicon substrate (3), it is a silicon oxide film, and the silicon oxide film as the insulating layer (17) is formed, for example, with a thickness of about 150 nm. In this silicon oxide film, at least the upper surface insulating layer (17T), the side surface insulating layer (17S) and the bottom insulating layer (17B) of the recess (4B) are formed on the silicon substrate (3), but the silicon substrate (17B) is formed. It may also be formed on the back surface or the side surface of 3). This thermal oxidation method is very dense because it is formed by growing an oxide film from the surface of the material by heating the uneven portion of the silicon substrate (3), which is the material to be oxidized, in a gas atmosphere of oxygen or water vapor. , An oxide film having good adhesion can be obtained that is integrated with the material. In this thermal oxidation method, the film thickness can be accurately controlled by adjusting the flow rate of the gas atmosphere and the heating time, and oxidation of an oxide film having a film thickness of several nm to a film thickness on the order of microns. Even a film can be easily obtained.

<Formation of insulating layer by anodizing method>
In this anodic oxidation method, a silicon substrate (3), which is a conductive material to be oxidized, is immersed in an electrolytic solution, and the material is energized as an anode (positive electrode, positive electrode), so that oxygen in the electrolytic solution is generated on the surface of the material. It is a method of forming an oxide film by growing it from the surface of the material. Here, when the oxide film formed on the surface of the material is not dissolved or an electrolytic solution having a low solubility is used, the anodizing method is very precise because the film formation proceeds as described above. An oxide film with good adhesion that is integrated with the material can be obtained. Further, in the anodizing method, since the film thickness of the oxide film is proportional to the applied voltage, the film thickness can be accurately controlled by adjusting the voltage, and the oxide film having a film thickness of several nm can be controlled accurately. It is possible to easily obtain an oxide film having a film thickness of several μm. Therefore, this anodizing method is suitable as a method for forming the insulating film 34 in the electroforming method of the electroforming process.

<Formation of an insulating layer by chemical vapor deposition (CVD method)>
When the insulating layer (17) is deposited and formed on the entire surface of the silicon substrate (3) on which the uneven structure is formed by the chemical vapor deposition method, for example, tetraethoxysilane (TEOS) is heated. , TEOS gas is generated by bubbling with a carrier gas, and an oxidizing gas such as oxygen or ozone and a diluting gas such as helium are mixed with the TEOS gas to generate a raw material gas. Then, this raw material gas is introduced into a CVD device such as a plasma CVD device or a room temperature ozone CVD device, and has a predetermined thickness (for example, about) on the surface of the silicon substrate (3) in the CVD device as an insulating layer (17). A silicon oxide film (40 nm, etc.) is formed. Here, by using aluminum isopropoxide instead of tetraethoxysilane, an alumina film having a predetermined thickness (for example, about 30 nm or the like) is formed as the insulating layer (17) by CVD. Since this CVD is a surface chemical reaction of the raw material gas, a dense film can be formed on the inner wall of the structure (inner surface of the slit groove SD in this embodiment) without any special device, and the film can be formed. A film can be relatively easily formed with a thickness of several nm to several μm.

<Formation of insulating layer by sputtering method>
When the insulating layer (17) is deposited and formed by the sputtering method, for example, a target of a substance (for example, quartz, alumina, etc.) to be formed as the insulating layer (17) is installed in the vacuum chamber, and the height is high. Noble gas elements such as argon (usually using argon) ionized by applying a voltage irradiate and collide with the target. Atoms on the surface of the target are repelled (sputtered) by this collision. When the repelled atoms (sputtering particles) reach each surface of the uneven portion of the silicon base material, the sputtering particles are deposited and deposited on the surface on the main surface side to form an insulating layer.

<Formation of insulating layer by vacuum deposition method>
As a method of forming an insulating layer by a vacuum vapor deposition method, a silicon substrate (3) is arranged so as to face a substance (deposited source) to be deposited as an insulating layer (17) in a vacuum chamber, and the vapor deposition source is heated. The film-forming substance (deposited substance) in a gaseous state generated by this is irradiated on the surface on the main surface side. When the vapor-deposited substance reaches the surface on the main surface side, the vapor-deposited substance is deposited and deposited on the surface on the main surface side to form a film. Vacuum evaporation method is ^usually to be carried out under a reduced pressure of about 10 ^{-2 to 10} -4 Pa, the mean free path of the deposition material, as long as about several 10cm~ number 10 m, the silicon substrate with almost no collision ( The vaporized material vaporized from the vapor deposition source to reach 3) has extremely good directivity. Therefore, a uniform and dense insulating layer can be formed deep inside the inner surface of the recess (4B) having a relatively high aspect ratio.

(Protective mask forming process)
Next, a protective mask (18) that functions as a mask is formed when the bottom insulating layer is peeled off in the next step.

As a method for forming the protective mask (18), a CVD method, a sputtering method, a vapor deposition method, or the like can be applied. Among them, a thick silicon oxide film (SiO) is formed by a chemical vapor deposition method (CVD method). _{A method of forming a film (two} layers) is preferable, and for example, it is formed by a CVD apparatus such as a plasma CVD apparatus or a room temperature ozone CVD apparatus using tetraethoxysilane (TEOS).

(Removal of bottom insulating layer)
Next, the bottom insulating layer (17B) formed at the bottom of the recess is removed by using the same etching apparatus (E) as that used in the deep digging step.

(Electroforming process of filling the recesses with metal components)
Finally, as shown in FIG. 6D, the high aspect diffraction grating (20) can be produced by filling the inside of the recess with the metal component (21) by electroforming.

A voltage is applied to the silicon substrate (3) by the electroplating method (electroplating method) as shown in FIG. 4 in the same manner as that used for forming the metal plating described above, and a metal component (metal component (metal component) is formed inside the recess. 21) is filled.

More specifically, similarly to the metal plating process shown in FIG. 4, the cathode electrode (12) of the power supply (13) is connected to the silicon substrate (3), and the anode electrode (12) is connected to the anode of the power supply (13). The silicon substrate (3) is immersed in the plating solution (11). As a result, the metal component (21) is precipitated from the bottom surface of the recess by electroforming and grows. Then, when the metal component (21) fills the inside of the slit-shaped recess, electroforming is completed.

In this way, the silicon component and the insulating layer function to transmit X-rays, and the slit-shaped metal component (21) formed in the plurality of recesses functions to absorb X-rays.

As the metal constituting the metal portion (21), a metal that absorbs X-rays is preferably selected, and for example, a metal or a noble metal having a relatively heavy atomic weight, more specifically, for example, gold (Au), or the like. Platinum (platinum, Pt), rhodium (Rh), ruthenium (Ru), iridium (Ir) and the like.

<< Features of the high-aspect diffraction grating of the present invention >>
FIG. 7 is a schematic cross-sectional view showing an example of the overall configuration of the high-aspect diffraction grating produced by the above method, and FIG. 8 is a schematic perspective view thereof.

As shown in FIG. 7, a feature of the high-aspect diffraction grating of the present invention is that the recess d4 filled with the metal component (21) has an unprecedented deep recess of 300 to 500 nm. Is a feature.

By the method for producing a high-aspect diffraction grating of the present invention, a diffraction grating having an extremely deep recessed structure can be produced, and as a result, an X-ray shielding portion composed of a layer-thick metal component can be formed. An X-ray imaging apparatus having high resolution can be realized.

The reason why the above configuration can be realized by the present invention is that, as shown in FIG. 9A, in the etching step for deep digging, when the diffraction grating having the conventional configuration is to dig deep in the recess (4B). The etching component (15) at the time of etching hits the side wall at the upper part of the convex portion, and the wall surface is deformed (22) by causing etching of a part of the side wall portion, so that the concave portion having a desired shape cannot be formed. It was difficult to produce a diffraction grating having a recessed depth of 300 μm or more.

In the present invention, the side wall of the upper surface of the convex portion, which is easily damaged by etching in the deep digging step as described in FIG. 5B, is metal-plated to protect the influence of etching on the silicon substrate. By forming Ms), as shown in FIG. 9B, a high-aspect diffraction configuration having a concavo-convex structure having a stable shape could be obtained. That is, even in a deep concavo-convex structure of 300 μm or more, a convex portion having a desired shape can be formed without damaging the tip portion.

《Application to Talbot Low Interferometer》
The high-aspect diffraction grating of the present invention can be applied to a Talbot-Lago interferometer.

FIG. 10 is a schematic configuration diagram showing an example of the configuration of a Talbot-Lago interference meter for X-rays to which the high-aspect diffraction grating of the present invention is applied.

As shown in FIG. 10, the Talbot low interferometer (50) includes an X-ray source (51), a multi-slit plate (G0), a first diffraction grating (G1), and a second diffraction grating (G2). Is configured with.

The multi-slit plate (G0) shown in FIG. 10 may be the high-aspect diffraction grating of the present invention. By manufacturing the multi-slit plate (G0) by the method for manufacturing a high-aspect diffraction grating of the present invention, a plurality of metal portions (21) having a sufficient thickness while transmitting X-rays through convex portions more reliably. ), So that the transmission and non-transmission of X-rays can be more clearly distinguished. Therefore, the multi-slit plate (G0) transmits the X-rays emitted from the X-ray source (51). A multi-light source can be used more reliably.

Then, by using the Talbot low interferometer (50), the X dose radiated toward the first diffraction grating (G1) through the subject (S) is increased as compared with the Talbot interferometer, so that it is higher. A sharp and good moire fringe is obtained.

(X-ray imaging device)
The high-aspect diffraction grating of the present invention can be used for various optical devices, but since it is possible to form a metal portion (21) having a high aspect ratio and a sufficient thickness, for example, X-ray imaging It can be suitably used for an apparatus.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. Although the display of "%" is used in the examples, it represents "mass%" unless otherwise specified.

<< Fabrication of diffraction grating >>
[Preparation of diffraction grating 1]
(Making a metal mask)
<1: Formation of aluminum layer on silicon substrate>
On the P-type silicon wafer, a sputtering modification machine SIH-450 manufactured by ULVAC was used to perform a sputtering treatment for 30 minutes under the condition of DC500W to form an aluminum layer having a thickness of 400 nm (see (a) in FIG. 2). ..

<Resist patterning>
After applying the resist on the aluminum layer by the spin coating method, the resist was patterned in a slit shape (L / S shape) with a width of 10 μm under the following conditions using an electron beam drawing apparatus (EB drawing).

As an electron beam drawing device (EB drawing), an electron beam direct drawing device F5112 manufactured by Advantest Co., Ltd. was used, and the exposure was performed at ^{6.1 μJ / cm 2.} As the resist, OEBR-CAP112PM manufactured by Tokyo Ohka Kogyo Co., Ltd. was used. The spin coating conditions were performed at 2500 rpm for 60 seconds.

<2: Patterning of aluminum layer>
The aluminum layer was patterned using the patterned resist as a mask. The etching of the aluminum layer was carried out using an Al etchant manufactured by Kanto Chemical Co., Inc. under the conditions shown below (see (b) in FIG. 2).

Etching by immersion at room temperature of 25 ° C. was performed for about 5 minutes using 100 ml of an etching solution (AI etchant). After etching, pure water washing was performed three times to remove the etching solution.

<3: Formation of recesses: Bosch process>
Next, the sample was etched using a mass-produced silicon deep digging device ASE-Pegasus manufactured by SPTS under the conditions shown below to form a plurality of uneven structures having a groove width of 10 μm and a groove depth of 60 μm. (See (c) of FIG. 2).

Conditions during etching using ASE-Pegasus was performed _RF1800W, platen180W, APC4.5Pa, in SF 6 gas300sccm at 6.7 S. Conditions during the protective layer formation was 3.1s _RF1800W, platen180W, APC3.5Pa, with C ₄ F 8 gas150sccm. This was alternately carried out for 50 cycles to obtain a structure having a depth of 60 μm.

<4: Filling the recesses with organic material>
Next, the formed recess was filled with OFPR-800LB manufactured by Tokyo Ohka Kogyo Co., Ltd. as an organic material at 3500 rpm using a spin coater. Then, the organic material was leveled and dried at 110 ° C. for 30 minutes (see (d) in FIG. 2).

<5: Removal of organic materials>
After filling the recesses with an organic material, oxygen ashing for 30 minutes is performed using an oxygen ashing device manufactured by SAMCO Corporation to remove 50 μm of the organic material formed at a thickness of 60 μm, and the bottom is thickened. 10 μm of organic material was left (see (a) in FIG. 3).

<6: Metal plating is applied to the top and side surfaces>
The silicon wafer from which the organic material other than the bottom of the recess was removed was electroplated (electroplated) by the electroplating method having the configuration shown in FIG. Gold (Au) liquid is used as the plating liquid, and plating treatment is performed for 5 minutes at a constant current of 1 mA. Was plated with a metal having a thickness of 200 nm (see (b) in FIG. 3).

<7: Removal of bottom organic material>
Next, the organic material having a thickness of 10 μm remaining at the bottom of the recess was peeled off and removed from the metal-plated silicon wafer using acetone.

Further, using FA-1 manufactured by SAMCO Corporation, oxygen ashing was performed for 30 minutes, and cleaning treatment was performed so that no residue of organic material remained on the bottom of the recess to prepare a metal mask 1 ((c) in FIG. 3). )reference).

<8: Deep digging>
Next, using the metal mask produced above, a deep digging process was performed to form a diffraction grating. Specifically, etching was performed using a mass-produced silicon deep digging device ASE-Pegasus manufactured by SPTS to prepare a high-aspect-concave-convex structure having a groove width of 10 μm and a groove depth of 300 μm ((FIG. 5). b) See).

<9: Chlorine etching process>
Next, the high-aspect uneven structure produced above is subjected to chlorine etching treatment by a plasma etching apparatus (E2) using a mixed gas of _{chlorine (Cl 2} ) and boron trichloride (BCl _{3), and the upper surface of the convex portion is subjected to chlorine etching treatment.} forming aluminum layer (3), metal plating _(M T, _{M S)} was peeled off (see FIG. 5 (c)).

<10: Formation of insulating layer>
Next, the obtained high-aspect-concavo-convex structure is subjected to thermal oxidation treatment to form an insulating layer having a thickness of 140 nm composed _{of SiO 2 on} the upper surface of the concavo-convex structure, the side surface of the recess, and the peripheral portion of the silicon wafer. Formed. The conditions of the thermal oxidation treatment were 1080 ° C. for 2 hours (see (a) in FIG. 6).

<11: Formation of upper surface mask layer>
Next, by a sputtering method, SiO ₂ was further laminated by 105 nm only on the upper surface portion to form a mask layer (see (b) in FIG. 6).

Sputtering was carried out at RF300W, 0.1Pa for 15 minutes using a sputtering machine manufactured by Osaka Vacuum Co., Ltd., and SiO2 was formed as a top mask layer at 105 nm.

<12: Removal of bottom insulating layer>
Next, etching was performed using a mass-produced silicon deep digging device ASE-Pegasus manufactured by SPTS, and only the bottom insulating layer was removed (see (c) in FIG. 6).

<13: Filling the inside of the recess of the metal component>
Next, by the electroplating method shown in FIG. 4, a gold plating solution was used to grow a gold component from the inside of the recess, and the entire inside of the recess was filled with gold to prepare a high-aspect diffraction grating 1.

Specifically, a gold plating solution (Microfab Au660) manufactured by Tanaka Kikinzoku Co., Ltd. was used to perform a plating treatment at a current density of ^{1.5 mA / cm 2 for 90 hours.} The liquid temperature of the gold plating liquid was maintained at 55 ° C.

[Preparation of diffraction grating 2]
In the production of the diffraction grating 1, the diffraction grating 2 was produced in the same manner except that the conditions were changed as follows.

(1) Change the groove depth in <3: Recess formation: Bosch process> to 80 μm (2) Change the oxygen ashing treatment time in <5: Removal of organic material> to 40 minutes (3) <6: Top surface And the metal plating on the side surface is changed to nickel (Ni). (4) The groove depth in <8: Deep digging> is changed to 400 nm.

[Preparation of diffraction grating 3]
In the production of the diffraction grating 1, the diffraction grating 3 was produced in the same manner except that the conditions were changed as follows.

(1) Change the groove depth in <3: Recess formation: Bosch process> to 100 μm (2) Change the oxygen ashing treatment time in <5: Removal of organic material> to 50 minutes (3) <6: Top surface And changed the plating metal type in <Applying metal plating to the side surface> to gold (Cu) (4) Changed the groove depth in <8: Deep digging> to 500 nm.

[Preparation of diffraction gratings 4 to 6]
In the production of the diffraction gratings 1 to 3, the diffraction gratings 4 to 6 were produced in the same manner except that the groove width of the metal mask was changed from 10 μm to 20 μm, respectively.

[Preparation of diffraction gratings 7 to 9]
In the production of the diffraction gratings 1 to 3, the diffraction gratings 7 to 9 were produced in the same manner except that the metal plating treatment in <6: Applying metal plating to the upper surface and the side surface portion> was not performed.

<< Appearance evaluation of diffraction grating >>
For each of the diffraction gratings produced above, the cross section of the diffraction grating was milled using an ion milling device manufactured by Hitachi High-Technologies Corporation, and then the shape of the uneven structure was observed using a scanning electron microscope (SEM). The appearance of the convex shape was evaluated according to the following criteria.

◯: There is no damage to the shape including the tip of the convex portion (silicon comb portion) Δ: Deformation as shown in FIG. 9 (a) due to long-term etching of the tip region of the convex portion (silicon comb portion). Occurrence of (constriction) Δ: The convex portion (silicon comb portion) has a shape collapse such as breakage due to etching for a long time. The results obtained as described above are shown in Table I.

As is clear from the results shown in Table I, the high-aspect diffraction grating produced by using the metal mask of the present invention has a convex portion even when deeply dug under the condition that the depth of the groove of the concave portion is 300 μm or more. It can be seen that there is no damage to the shape in the tip region of the above, and a diffraction grating having an excellent shape can be obtained.

1 Metal mask 2 Aluminum layer 3 Silicon substrate 4 Recess (metal mask)
4B Deep digging recess (diffraction grating)
5 Convex 6 Bottom 7 Organic material 8 Bottom organic material 9 Oxygen plasma device 10 Oxygen plasma 11 Plating liquid 12 Anode electrode 13 Power supply 15 Etching component 17 Insulation layer 17B Bottom insulation layer 17S Side insulation layer 17T Top surface insulation layer 18 Protection Mask 20 High-anode diffraction grating 21 Metal component 22 Deformation 50 Talbot low interferometer 51 X-ray source D Detector d1 Depth of groove in recess (metal mask)
d4 Depth of groove in recess (diffraction grating)
E etching apparatus E2 plasma etching apparatus G0 multi-slit plate, G0 diffraction grating G1 first diffraction grating, G1 a diffraction grating G2 second diffraction grating, G2 a diffraction grating M _S side metal plating unit M _T top metal plating portion P plasma S subject W1 Groove width of recess (metal mask)
Groove width of W2 recess (diffraction grating)

Claims (7)

A method for manufacturing a metal mask using a silicon substrate.
The first step of forming an aluminum layer on the silicon substrate and
After applying the resist on the aluminum layer, the resist is patterned, and then the aluminum layer is patterned in the second step.
A third step of etching the silicon substrate corresponding to the region from which the aluminum layer has been removed to form a lattice having an uneven structure, and
The fourth step of filling the recesses of the lattice with an organic material and solidifying it to form an etching resist.
The fifth step of removing the organic material by an etching method, leaving the bottom of the recess, and
The sixth step of applying metal plating to the upper surface portion and the side surface portion from which the organic material has been removed, and
A seventh step of removing the organic material left on the bottom of the recess,
A method for manufacturing a metal mask, which comprises manufacturing a metal mask through the process. The first aspect of the present invention is that the silicon substrate having the concavo-convex structure has a concavo-convex structure in which the groove width is in the range of 1 to 50 μm and the groove depth of the recess is in the range of 1 to 150 μm. The method for manufacturing a metal mask according to the description. The method for producing a metal mask according to claim 1 or 2, wherein the organic material is removed by treatment with acetone or oxygen plasma. A metal mask using a silicon substrate
The silicon substrate has a lattice having a concavo-convex structure, and
A metal mask characterized in that metal plating is applied to a side surface portion excluding the upper surface portion and the bottom portion of the convex portion of the concave-convex structure. A method for manufacturing a high-aspect diffraction grating using the metal mask according to claim 4.
An etching step of digging a concave portion of a silicon substrate of the metal mask having an uneven structure to a predetermined depth, and
A step of forming an insulating layer on the surface portion and the concave surface of the deeply dug silicon substrate on the side having the uneven structure, and
A step of removing the insulating layer formed on the bottom of the recess, and
A method for manufacturing a high-aspect diffraction grating, which comprises an electroforming step of filling the recesses with metal by an electroforming method. The method for manufacturing a high-aspect diffraction grating according to claim 5, wherein the metal used in the electroforming process is gold. A high-aspect diffraction grating using the metal mask according to claim 4.
A high-aspect diffraction grating characterized in that a lattice having a concavo-convex structure has a concavo-convex structure in which the tip portion is metal-plated and the depth of the groove of the recess is in the range of 300 to 500 μm.

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