JP2006028604A - Method for transferring minute shape, method for manufacturing casting mold, surface treatment method for casting mold, and casting mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive method for manufacturing a casting mold which does not require an electroforming duplication process and does not degrade the flatness of a master disk, a surface treatment method for the casting mold, and the casting mold. <P>SOLUTION: A resist 3 is applied onto the surface of an oxide film 2 formed on a substrate 1 having optical surface accuracy and a resist portion 4 is formed by a photomask forming, exposure and development steps. The anodically oxidized film exposed in an aperture 4a is selectively removed and the casting mold imparted with the groove pattern of from a submicron level to several tens micron level is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fine shape transfer method having a fine shape pattern, a mold manufacturing method, and a mold manufactured by this method.

Conventionally, a fine shape transfer method is a method for producing a mold having a fine shape pattern, a master material, photolithography, etching, plating processing, and other micro processing techniques such as providing a mold production method without electrodeposition stress. The main focus is to provide molding molds and manufacturing methods that do not impair flatness, to provide molds and manufacturing methods that do not require a duplication process, and to provide inexpensive molds and manufacturing methods that shorten processes (for example, patents). Reference 1 and 2).
In addition, the fine shape transfer method includes the provision of a mold with excellent pattern step accuracy and its manufacturing method, the provision of a mold with good pattern adhesion and its manufacturing method, the provision of a mold with good pattern durability and its manufacturing method, and heat conduction. The main purpose is to provide a mold that is excellent in performance and capable of shortening the molding cycle and a method for producing the mold.
Patent Document 1 discloses a plastic optical recording medium molding in which a resist pattern is formed on a base material made of crystalline silicon, amorphous silicon, or quartz with optical surface accuracy, and a fine pattern is formed by ion etching. Disclosed is a method for producing a casting mold.
In Patent Document 2, a single crystal silicon substrate is etched by a photolithographic technique to form depressions in an array. It is disclosed that a mold having a replica obtained by depositing nickel by electrocasting or the like in the array of depressions and press-molding a transparent resin material with the mold is disclosed.
However, in Patent Document 1, although the silicon and quartz substrates are ion-etched to form a molding mold while the fine line pattern is formed, there is no deterioration in accuracy in repeated transfer duplication, and there is an advantage that there are few defects such as dust particles. The mold for injection molding has disadvantages that cannot be put into practical use in terms of secondary processability, heat resistance, and mechanical strength.
Moreover, in patent document 2, the said hollow pattern is transcribe | transferred by nickel electroforming from the silicon substrate in which the uneven | corrugated pattern was formed. The molding mold needs to have a nickel thickness of about 3 to 5 mm, and it takes 10 days if the number of days such as machining is included in addition to the number of days of electroforming replication.
Furthermore, there is a process defect that becomes a mold that is deteriorated by about 50 to 100 times from the flatness of the initial silicon substrate due to warpage and deformation due to plating internal stress during electroforming.

FIG. 5 is a schematic sectional view showing a conventional silicon mold making or Ni electroforming replication process. In the conventional mold manufacturing process of FIG. 5, first, a silicon single crystal substrate (hereinafter referred to as a silicon substrate) 1 is prepared.
The mirror-polished silicon substrate 1 exhibits excellent properties in terms of both flatness and surface roughness, and is suitable for a precision mold. A generally available silicon substrate has a thickness of 0.5 mm or less.
A resist 3 is applied on one side of a silicon substrate 1 (FIG. 5 (a)) having a thermal oxide film 2 formed on both sides (FIG. 5 (b)), and then subjected to an exposure / development process (FIG. 5 (c)). A desired resist opening pattern 4 is formed (FIG. 5D).
According to the electron beam resist and electron beam direct drawing, a nano-order resist pattern can be formed. Hereinafter, an example of forming an ultraviolet photosensitive resist pattern will be described.
The thermal oxide film 2 in the resist opening formed by the photolithography process is dissolved and removed with a dilute hydrofluoric acid solution (h). When the silicon oxide film is etched with a heated potassium hydroxide aqueous solution as an etching resist, the portion without the thermal oxide film 2 is etched into a concave shape (i).
FIG. 6 is a schematic sectional view for explaining an embossing molding process. The etching rate varies depending on the crystal orientation of the silicon substrate 1, and an uneven pattern having a shape according to the crystal orientation can be formed.
In general, the thickness of the silicon substrate 1 is 0.5 mm or less, and if the etched silicon substrate 1 is used as it is for embossing, there is a problem that the mold is broken (FIG. 6). Therefore, the silicon mold is used as a master and is transferred and duplicated by nickel electroforming.
If the nickel replica type is used, the disadvantage of breakage during handling is improved. Nickel electroforming on the silicon mold 5 and finally separating the silicon and nickel parts (FIG. 5 (j)) yields a nickel replica that is inversion-matched with the silicon master pattern (FIG. 5 (k)).
Japanese Patent No. 2531472 JP 2001-133772 A

In general, it takes about 5 to 10 days to produce a nickel replica mold having a thickness of about 3 mm, including the final outline processing. Due to the thinness of the silicon master and the electrodeposition stress during nickel electroforming, the flatness of the nickel replica mold is lower than that of the master.
Although it depends on the external dimensions of the replica type, the flatness is about 50 microns with a diameter of 50 mm. Since the flatness of the silicon master disk is about 1 micron level, it deteriorates about 50 times.
There was a big problem that the flatness deteriorated in the duplication. When warping deformation is large, a region that does not come into contact with the substrate of the transfer object is generated, and the target transfer cannot be performed. Electrodeposition stress control, which is a warping deformation factor, requires a lot of know-how and experience, such as liquid management, film thickness management, and addition of stress reducing agents.
Accordingly, an object of the present invention is to provide an inexpensive mold manufacturing method, mold surface treatment method, and mold that do not deteriorate the flatness of the master disk by a simple processing process that does not require an electroforming duplication process in consideration of the above-described circumstances. is there.

In order to solve the above-mentioned problem, the invention according to claim 1 is a fine pattern in which shape transfer is performed with a fine pattern formed by selectively removing an oxide film formed on a substrate having optical surface accuracy. Features a shape transfer method.
The invention described in claim 2 is characterized by a mold manufacturing method in which shape transfer is performed with a fine pattern formed by selectively removing an oxide film formed on a substrate having optical surface accuracy.
According to a third aspect of the present invention, there is provided a mold manufacturing method according to the second aspect in which an aluminum oxide film is formed as the oxide film.
According to a fourth aspect of the present invention, there is provided a mold manufacturing method according to the third aspect, wherein an aluminum substrate, a glass with a sputtered aluminum film, or a ceramic substrate is used as the substrate.
The invention according to claim 5 is characterized in that the mold manufacturing method according to claims 3 and 4 is such that a natural oxide film, a chemical oxide film, or an anodic oxide film is used as the oxide film.
The invention described in claim 6 is characterized by the mold manufacturing method according to claim 5, wherein the oxide film is etched into a target shape to form a mold pattern.
The invention according to claim 7 is characterized by a mold surface treatment method in which the Vickers hardness of the anodized film is Hv150 to 350.

The invention according to claim 8 is characterized by a mold manufacturing method in which the under film Vickers hardness of the anodized film is Hv150-200 and the outermost film Vickers hardness is Hv200-350.
According to a ninth aspect of the present invention, in the method for forming the anodic oxide film, the liquid temperature at the initial stage of electrolysis is set to 0 to 10 ° C., and then the anodic oxidation treatment is performed in two stages of 20 ± 2 ° C. The mold manufacturing method according to claim 8 is characterized.
The invention described in claim 10 is characterized by a mold in which a thin film resistor is integrally disposed on the back surface of the mold.
The invention according to claim 11 is characterized in that a mold manufacturing method is provided in which a thin film resistor is integrally disposed on the back surface of the mold.
According to a twelfth aspect of the present invention, there is provided the mold according to the tenth aspect, wherein the thin film resistor is formed in a form corresponding to the mold pattern arrangement in the mold structure.
The invention according to claim 13 is characterized in that, in the mold structure, the aluminum anodic oxide film is an electrical insulating layer of a thin film resistor.
The invention according to claim 14 is characterized in that, in the mold structure, the aluminum anodic oxide film is an electric insulating layer of a thin film resistor, and the mold manufacturing method according to claim 11.

  According to the present invention, since the anodic oxide film treatment does not generate electrodeposition stress as in nickel electroforming, warping deformation does not occur, so that there is an effect that a mold having excellent front surface transferability and a mold manufacturing method can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a first embodiment of a mold manufacturing process according to the present invention. In FIG. 1, first, a substrate material 1 to be a base of a mold master is prepared (FIG. 1 (a)).
In this embodiment, an aluminum A5052 material having excellent anodizing properties is used. The master surface is finished by machining to the desired flatness and surface roughness. In the present embodiment, one surface of the aluminum substrate is ultra-precisely cut with a silicon single crystal cutting tool to obtain a substrate flatness of 5 μm or less and a surface roughness Rz of 0.1 μm or less.
After this aluminum substrate 1 is fixed to a jig (not shown), an anodic oxide film 2 is formed by anodic electrolysis at a sulfuric acid aqueous solution of 10-20 Vol%, an electrolysis temperature of 20 ± 1 ° C., and a voltage of 10-20 V. A flat plate of aluminum, platinum, or lead is used for the cathode.
A cooler and a liquid circulation pump were used in combination to prevent the liquid temperature from rising due to Joule heat during electrolysis. When the thickness of the anodic oxide film 2 is a certain thickness, it follows the Faraday rule. When the target thickness is reached, stop energization.
The substrate 1 is removed from the jig after being drawn out from the liquid, washed with water and dried. In the anodic electrolysis of aluminum, an aluminum anodic oxide film 2 grows in the thickness direction of the substrate. The film thickness can be controlled from the submicron range to the order of several tens of microns depending on the amount of current.
Next, the photolithography process is started. A photosensitive resin (resist) 3 is applied to the surface of the anodic oxide film 2 of the substrate 1 (FIG. 1C). After applying the resist 3, a target resist pattern 4 (3) is formed through a photomask formation and exposure / development steps (FIG. 1 (d)).
In the opening 4a formed in the resist pattern 4, the anodic oxide film 2 is exposed. The anodic oxide film 2 in the resist opening is removed by etching with a sulfamic acid aqueous solution or a phosphoric acid aqueous solution (e). The anodic oxide film in the resist opening is dissolved and removed to expose the aluminum of the substrate metal 1 (f).
Since there is a difference in the etching rate between the anodized film 2 and the aluminum substrate metal, the depth of the mold groove is almost determined by the thickness of the anodized film. A mold 5 provided with a groove pattern of submicron to several tens of microns can be manufactured only by anodizing and etching processes.

As described above, the first feature of the fine shape transfer method or the mold manufacturing method according to the present invention is the fine pattern 2 formed by selectively removing the oxide film 2 formed on the substrate 1 having optical surface accuracy. The point is that the shape is transferred at the point. The point is that shape transfer is performed with a fine pattern formed by selectively removing an oxide film formed on a substrate having optical surface accuracy.
As the oxide film 2, for example, an aluminum oxide film is used. Further, a natural oxide film, a chemical oxide film, or an anodic oxide film is used as the oxide film. The oxide film 2 is etched into a target shape to form a mold pattern.
As the substrate 1, an aluminum substrate, a glass on which an aluminum sputtered film is formed, or a ceramic substrate can be used.
The Vickers hardness of the anodic oxide film 2 is set to Hv 150 to 350.
The under film Vickers hardness of the anodic oxide film 2 may be a two-layer structure of Hv 150 to 200, and the outermost shell film Vickers hardness may be Hv 200 to 350.
In the method of forming the anodic oxide film 2, the liquid temperature at the initial stage of electrolysis is set to 0 to 10 ° C., and thereafter, the anodic oxidation treatment is performed in two steps of 20 ± 2 ° C.

FIG. 2 is a schematic cross-sectional view showing a second embodiment of a mold manufacturing process according to the present invention. In the second embodiment of the present invention, a non-metallic substrate 11 such as glass or ceramics is used as a master material (FIG. 2A).
For example, if a plate glass substrate is used, the substrate 11 having excellent specularity and flatness and having an optical surface accuracy can be easily obtained at low cost. Since the glass substrate 11 cannot be anodized as it is, it is necessary to form a sputtered aluminum film.
After the glass substrate 11 is cleaned, a transparent conductive film (ITO) 12 is formed to a thickness of about 500 to 1000 nm on the mold pattern formation surface (FIG. 2B). Subsequently, a sputtered aluminum film 13 having a thickness of 1000 to 2000 nm is formed (FIG. 2C).
Anodization is performed in an electrolytic solution containing phosphoric acid as a main component (FIG. 2D). Anodizing film 14 is formed by anodizing to a desired mold pattern thickness. When the anodic oxidation is completed, the substrate 11 is taken out after washing and drying.
A resist pattern is formed by the same photolithography process as in the first embodiment (FIG. 2E), and exposure and development are performed using an exposure mask to form a pattern of the anodic oxide film 14 ((f) , (G)), the sputtered film 13 in the opening of the anodic oxide film 14 is removed by etching (FIG. 2 (h)), and if the anodic oxide film 14 is further removed, the step of the aluminum sputtered film 13, the ITO substrate surface 12, A mold 15 having a fine pattern made of the metal substrate 11 is completed (FIG. 2 (i)). A mold master 15 having a flatness substantially equal to the original substrate flatness is obtained.
As in the first embodiment, the third embodiment of the mold manufacturing process according to the present invention uses an aluminum anodic oxide film etched to form a fine pattern consisting of an oxide film and a substrate exposed surface as a mold. is there.
The electrolytic solution temperature in aluminum anodic oxidation was processed within a range of 0 to 10 ° C. As a result, the hardness of the anodic oxide film becomes a hard film of Hv 200 to 350, and the mold wear resistance is improved when an embossing mold is used.
In the fourth embodiment of the mold manufacturing process according to the present invention, as in the first embodiment, an aluminum anodic oxide film is etched and a fine shape pattern consisting of an oxide film and a substrate exposed surface is used as a mold. It is.
After the initial temperature of the electrolytic solution for aluminum anodization was processed within the range of 0 to 10 ° C., the electrolytic solution was heated to continuously perform electrolytic processing within 20 ± 1 ° C. The outermost shell layer of the anodic oxide film is a hard film of Hv 200 to 350, and the substrate-side under layer has a two-layer structure in terms of film hardness of Hv 150 to 200, thereby preventing a rapid change in hardness with the material.
The two-layer structure improved the film cracking and impact resistance. Depending on the target material in resin molding, transfer molding conditions, application, etc., the third embodiment is properly used.

FIG. 3 is a schematic cross-sectional view showing a heater built-in mold according to a fifth embodiment of the present invention. 4 is a plan view showing the back surface of the heater built-in mold in FIG. 3 and 4, the mold is a heater built-in mold in which an anodic oxide film pattern 16 is formed on one surface and an electric heater pattern 17 is formed on the back surface of the anodic oxide film pattern 16.
Similar to the first embodiment, an aluminum substrate 11 is prepared. In the fifth embodiment, both surfaces of the substrate 11 are anodized. On one side, as in the first embodiment, an anodized film is formed and an etching pattern is formed to form a template pattern 12 with a target anodized film. A thin film heater member (thin film resistor) 17 is bonded and bonded onto the anodized film 16 on the back surface.
In this mold structure, the aluminum anodic oxide film 16 is preferably used as an electrically insulating layer of the thin film heater member (thin film resistor) 17.
The thin-film heater member 17 is obtained by bonding a Ni—Cr metal foil onto a polyimide film with a polyimide heat-resistant adhesive and performing thin line etching into a resistor pattern. Alternatively, after a Ni—Cr alloy foil is bonded to one surface of the anodized substrate surface with a polyimide heat-resistant adhesive, a thin line pattern of an electric resistor is formed.
In either case, the resistance pattern is partially laid out in a relationship corresponding to the template pattern formed by etching the anodic oxide film so that local heating can be performed. A mold having a fine pattern formed from the anodized film and the exposed portion of the aluminum substrate is obtained.
Since the anodic oxide film is grown directly from the substrate metal, the adhesion is extremely good. Since there is no generation of electrodeposition stress as in nickel electroforming, a mold having a fine shape that maintains the flatness of the original substrate can be obtained. Because it is metal, there is no crack or damage. Since it is not necessary to duplicate only by etching, the process can be shortened and an inexpensive mold can be provided.
Since it is aluminum, it can be used repeatedly by cutting and anodizing the surface. Ultimately, it can be recycled as a raw material, which is advantageous from the viewpoint of saving materials.
A mold master that gives a hard fine pattern when the alumina Al ₂ O ₂ portion is etched by photolithography because the hard material of alumina Al ₂ O ₂ can be formed with good adhesion by anodizing metal aluminum in the electrolyte There is an effect that can be produced.

The anodic oxide film treatment does not generate warping deformation because no electrodeposition stress is generated as in nickel electroforming, and thus has an effect of obtaining a mold having excellent front surface transferability. Since the anodic oxide film is grown directly from the substrate, it has the effect of obtaining a template pattern with excellent adhesion.
Since aluminum is used as a mold material, it has excellent thermal conductivity, and therefore, when applied to an embossing mold, the molding cycle can be shortened. Since aluminum is used as a mold material, it has an effect of obtaining a mold that does not break or break during transfer and handling.
There is an effect that it is possible to provide an inexpensive mold using only an anodizing and etching using an inexpensive aluminum substrate. Since the mold material is aluminum, it can be reused and recycled, so it has excellent effects in terms of material saving and environmental aspects.
Since the thickness of the anodic oxide film can be easily made constant, there is an effect that it is possible to form a casting mold having a uniform uneven pattern. Since a hard anodic oxide film can be formed by controlling electrolytic conditions, it has an effect of obtaining a mold having excellent wear resistance and durability.
The anodic oxide film is provided with fine holes, and has an effect that different characteristics can be obtained by metal filling. Due to the difference in etching rate between the anodic oxide film and the substrate material, there is an effect that a mold having a constant step pattern can be formed.
Due to the ease of etching, it is possible to easily form a mold free of pattern density. There is an effect that a template having a large degree of freedom in pattern layout can be obtained two-dimensionally. Since the etching pattern of the anodic oxide film is used as a mold, it is possible to obtain a mold that does not require a replication process.
Glass having good substrate specularity and flatness, and an aluminum sputtered film on a ceramic substrate are anodized and etched, so that a nanometer level mold can be easily obtained.
The present invention relates to a micro component applying a micro processing technology such as a master material, photolithography, etching, plating film formation, and a mold manufacturing method thereof, embossing, and a fine shape transfer technology such as nanoimprinting.
In addition, light guide plate forming method and mold manufacturing field, ink jet recording head channel plate forming and mold manufacturing field, microfluidic device and molding mold manufacturing field, optical writing head light guide path manufacturing field, and molding of micro three-dimensional structural parts. It can also be used in the mold manufacturing field.

1 is a schematic sectional view showing a first embodiment of a mold manufacturing process according to the present invention. The schematic sectional drawing which shows 2nd Embodiment of the mold manufacturing process by this invention. The schematic sectional drawing which shows the heater built-in type | mold mold | die which is 5th Embodiment by this invention. The top view which shows the heater built-in type | mold mold back surface of FIG. Schematic sectional view showing a conventional silicon mold making or Ni electroforming replication process. The schematic sectional drawing explaining an embossing shaping | molding process.

Explanation of symbols

1 substrate (aluminum substrate)
2 Aluminum anodic oxide film 3 Resist 5 Mold 11 Substrate (glass substrate)
12 ITO film (transparent conductive film)
13 Aluminum oxide film 14 Resist 15 Mold 16 Anodized film (electrical insulating layer)
17 Thin film resistor (thin film heater member)

Claims (14)

  A fine shape transfer method characterized in that shape transfer is performed with a fine pattern formed by selectively removing an oxide film formed on a substrate having optical surface accuracy.   A mold manufacturing method characterized in that shape transfer is performed with a fine pattern formed by selectively removing an oxide film formed on a substrate having optical surface accuracy.   3. The mold manufacturing method according to claim 2, wherein an aluminum oxide film is formed as the oxide film.   4. The mold manufacturing method according to claim 3, wherein an aluminum substrate, a glass on which an aluminum sputtered film is formed, or a ceramic substrate is used as the substrate.   5. The mold manufacturing method according to claim 3, wherein a natural oxide film, a chemical oxide film, or an anodic oxide film is used as the oxide film.   6. The mold manufacturing method according to claim 5, wherein the oxide film is etched into a target shape to form a mold pattern.   A mold surface treatment method characterized in that the Vickers hardness of the anodized film is Hv 150 to 350.   2. A method for producing a mold, characterized in that the anodized film has a two-layer structure of an under film Vickers hardness of Hv 150 to 200 and an outermost shell film Vickers hardness of Hv 200 to 350.   9. The method of forming an anodic oxide film according to claim 8, wherein a liquid temperature at an initial stage of electrolysis is set to 0 to 10 [deg.] C., and thereafter an electrolytic temperature is anodized in two steps of 20 ± 2 [deg.] C. Mold making method.   A mold characterized in that a thin film resistor is integrally disposed on the back of the mold.   A method for producing a mold, characterized in that a thin film resistor is integrally disposed on the back surface of the mold.   11. The mold according to claim 10, wherein in the mold structure, a thin film resistor is formed in a form corresponding to the mold pattern arrangement.   11. The mold according to claim 10, wherein in the mold structure, the aluminum anodic oxide film is an electric insulating layer of a thin film resistor.   12. The mold manufacturing method according to claim 11, wherein in the mold structure, the aluminum anodic oxide film is an electrically insulating layer of a thin film resistor.

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