JP4966694B2 - Manufacturing method of microstructured mold - Google Patents

Description

  The present invention relates to a method for manufacturing a microstructure mold capable of transferring a nanometer-scale microstructure and a micrometer-scale concavo-convex structure.

  Along with the development of microfabrication technology in the semiconductor industry in recent years, analysis using a microchip in which elements necessary for chemical analysis such as microchannels, reactors, and electrodes for detection are integrated on a substrate such as silicon or glass. Equipment has come to be used. Microchip-based electrophoresis devices for DNA and proteins have already been developed and marketed.

  Such microfluidic chip-based analysis devices (micro-analysis system, μ-Total Analysis System, μ-TAS) enable integration of chemical analysis experiments, high throughput, resource saving, space saving, and low emission Currently, separation chips that perform electrophoresis and chromatography as described above, focusing on biochemical analysis, assay chips that perform immunoassay and enzyme analysis, synthesis reaction chips that perform polymerase chain reaction (PCR), etc. Development is active on a global scale. Since these are easy to carry, it is expected that it will be possible to conduct environmental analysis on the spot sampled and to conduct high-precision clinical trials at the bedside.

  In order to manufacture each of the above devices, it is necessary to form a nanometer-scale microstructure or a micrometer-scale structure. Therefore, a mold having a nanometer-scale microstructure or a micrometer-scale concavo-convex structure is prepared. It is manufactured by a method of transferring a nanometer-scale fine structure pattern or a micrometer-scale concavo-convex structure formed on a mold by a nano or microimprint method to a resin substrate.

The mold is manufactured by a lithography method or a metal plating method. For example, a molecular electroless plating catalyst is applied to the surface of a substrate having a fine uneven structure on the surface, followed by electroless plating. Forming a metal layer filled with at least the uneven pattern, and further separating the metal layer from the substrate to obtain a fine metal structure having a surface on which the uneven pattern is reversely transferred. A method for manufacturing a fine metal structure has been proposed (see, for example, Patent Document 1).
JP 2005-189128 A

  However, in the above manufacturing method, a metal structure is formed by performing electroless plating on the surface of the substrate, and then the fine uneven pattern formed on the surface of the substrate is simply transferred to the metal structure by peeling the substrate from this. Therefore, it has been difficult to accurately manufacture a mold having both a nanometer-scale microstructure and a micrometer-scale concavo-convex structure in which the original device manufacturing method must be different.

  An object of the present invention is to provide a manufacturing method capable of accurately obtaining a mold having both a nanometer-scale microstructure and a micrometer-scale concavo-convex structure in view of the above-mentioned drawbacks.

  According to a first aspect of the present invention, there is provided a method for producing a microstructured mold comprising: (1) forming a transparent thin film having a thickness of 10 nm to 10 μm on a transparent substrate (a) having a micrometer-scale light-shielding pattern formed on one surface; Step 1 (2) A photoresist is applied on a transparent thin film in a thickness of 5 μm to 5000 μm to form an uncured thick film photoresist layer, and then a nanometer-scale fine film is formed on the uncured thick film photoresist layer. A second step of laminating and pressing the substrate (b) on which the structure is formed; (3) curing the uncured thick film photoresist layer by exposing it from the other surface of the transparent substrate (b); After forming the layer, the substrate (b) is peeled off, and then the uncured photoresist of the cured thick film photoresist layer is washed away to form a concave structure on the micrometer scale, and (4) Na This is a fourth step in which a metal layer is laminated by electroforming on the surface of a cured photoresist layer on which a metric scale fine structure transfer structure and a micrometer scale concave structure are formed, and then the photoresist is peeled off from the metal layer. It is characterized by that.

  Next, an example of a method for producing a microstructure mold according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a first step of the present invention. In the figure, reference numeral 1 denotes a transparent substrate (a). In the first step (1), a micrometer-scale light-shielding pattern 2 is formed on one surface of the transparent substrate (a) 1, and a photoresist is thickened thereon. After coating in the form of a thin film having a thickness of 10 nm to 2 μm, the cured transparent thin film photoresist layer 3 is formed by exposure from the side without the light shielding pattern.

  The material for the transparent substrate (a) 1 may be transparent, and examples thereof include polydimethylsiloxane (PDMS), glass, quartz, silicon, and a photoreactive resin.

  First, a micrometer-scale light shielding pattern 2 is formed on one surface of a transparent substrate (a) 1. The light-shielding pattern 2 is preferably one having excellent light-shielding properties, in particular, light-shielding properties of light near 360 nm used when curing a photoresist, and examples thereof include chromium. The light-shielding pattern 2 is a micrometer scale, and the width and height are preferably 5 to 5000 μm. Moreover, the formation method of the light-shielding pattern 2 should just employ | adopt conventionally well-known arbitrary formation methods.

As a method of forming a transparent thin film on the surface of the transparent substrate (a) 1 on which the light-shielding pattern 2 is formed, various coating methods such as spin coating, spraying, screen printing, etc., such as photoresist, and chemical gases such as SiO ₂ are used. A phase growth method (CVD method), a sol-gel method using metal alkoxide, a physical vapor deposition method (PVD method) such as vacuum deposition / sputtering, or the like can be selected.

  The photoresist is a photo-curing resin mainly composed of an acrylic resin such as polyester acrylate, epoxy acrylate or urethane acrylate, an epoxy resin, a vinyl ether resin or a silicone resin, and is generally used as a photoresist. Can be used. The photoresist is applied in the form of a thin film having a thickness of 10 nm to 2 μm on the surface of the transparent substrate (a) 1 on which the light shielding pattern 2 is formed. The coating method is not particularly limited, and any conventionally known coating method may be employed. However, since the coating method is performed in a thin film shape of 10 nm to 2 μm, a spin coating method capable of uniform and accurate coating is employed. Is preferred.

  After the photoresist is applied in a thin film shape having a thickness of 10 nm to 2 μm, as shown by an arrow in FIG. 1, the photoresist is cured by exposure from the side without the light shielding pattern 2 to form a cured transparent thin film photoresist layer 3.

  2 and 3 are sectional views showing a second step (2) of the present invention. First, as shown in FIG. 2, an uncured thick film photoresist layer 4 is formed on the cured transparent thin film photoresist layer 3 by applying a photoresist in a thickness of 5 μm to 5000 μm. Next, a substrate (b) 5 on which a nanometer-scale fine structure pattern 51 is formed is laminated and pressed on the uncured thick film photoresist layer 4. Since the photoresist of the uncured thick film photoresist layer 4 is not cured, it has fluidity, and the uncured thick film photoresist is formed on the nanometer-scale microstructure 51 formed on the surface of the substrate (b) 5. Inflow.

  The material which comprises the board | substrate (b) 5 is not specifically limited, For example, polydimethylsiloxane (PDMS), glass, quartz, a silicon | silicone, photoreactive resin metal, ceramics, those combinations, etc. are mentioned.

  Also, the method for forming the nanometer-scale fine structure pattern 51 is not particularly limited. For example, a transfer technique represented by machining, injection molding or compression molding, dry etching (RIE, IE, IBE, plasma etching). , Laser etching, anisotropic etching, laser ablation, blasting, electrical discharge machining, LIGA, electron beam etching, FAB), wet etching (chemical erosion), integrated molding such as stereolithography and ceramic laying, various materials in layers Surface, micro-machining, which forms fine structures by coating, vapor deposition, sputtering, deposition, and partial removal, and forming grooves by forming openings with one or more sheets of material (film, tape, etc.) How to do inkjet or dispenser Dropping more flow path forming material, and a method of forming by implantation and the like.

  The photoresist that forms the cured transparent thin film photoresist layer 4 is a photo-curing resin mainly composed of an acrylic resin such as polyester acrylate, epoxy acrylate, or urethane acrylate, an epoxy resin, a vinyl ether resin, a silicone resin, or the like. Any material generally used as a photoresist can be used. It may be the same or the same type of photoresist as that constituting the cured transparent thin film photoresist layer 3.

  The method for coating the photoresist is not particularly limited, and any conventionally known coating method may be adopted. However, it is applied to a thick film of 5 μm to 5000 μm, and it is preferable that the photoresist is uniformly coated. It is preferable to employ a spin coating method. Further, the cured transparent thin film photoresist layer 4 is used to form a concave structure on the micrometer scale in a subsequent process, so that the thickness thereof is 5 μm to 5000 μm.

  4-6 is sectional drawing which shows the 3rd process (3) of this invention. First, as shown in FIG. 4, the uncured thick photoresist layer 4 is cured by exposing in the direction of the arrow from the other surface of the transparent substrate (a) 1. The uncured thick film photoresist layer 4 that is not shielded by the light shielding pattern 2 is cured to become a cured thick film photoresist layer 41, and the uncured thick film photoresist layer 4 that is shielded by the light shielding pattern 2 is not cured as an uncured photoresist 42. Exists.

  After the cured thick film photoresist layer 41 is formed, the substrate (b) 5 is peeled off. By peeling off the substrate (b) 5, the nanometer-scale microstructure 51 formed on the surface of the substrate (b) 5 is transferred to the cured thick film photoresist layer 41, and is the same nanometer scale as the microstructure 51. A fine transfer structure 43 is formed on the surface of the cured thick film photoresist layer 41.

  The width and height of the nanometer-scale microstructure 51 are preferably 10 to 1000 nm. In addition, the width of the nanometer-scale microstructure is preferably smaller than a half wavelength of light for curing the photoresist, and the height of the microstructure is preferably a half wavelength or more. A substrate (b) on which a nanometer-scale microstructure is formed is transparent to light for curing the photoresist.

  The uncured photoresist 42 is then washed away from the cured thick film photoresist layer 41 to form a micrometer scale concave structure 44. Since the planar shape of the uncured photoresist 42 is the same as that of the light shielding pattern 2, the planar shape of the concave structure 44 is the same as that of the light shielding pattern 2. At this time, the cured thick film photoresist layer 41 and the transparent thin film are joined to form a transparent structure in which a nanometer-scale fine structure transfer structure 43 and a micrometer-scale concave structure 44 are formed.

  FIG. 7 is a cross-sectional view showing the fourth step (4) of the present invention, and FIG. 8 is a cross-sectional view showing the obtained microstructured mold. First, the metal layer 6 is laminated | stacked by the electroforming method on the transparent structure surface in which the transfer structure 43 of the fine structure of nanometer scale and the concave structure 44 of micrometer scale were formed.

  Next, when the transparent structure is peeled and removed from the metal layer 6, as shown in FIG. 8, the nanometer-scale microstructure 71 on which the transfer structure 43 of the surface nanometer-scale microstructure of the transparent structure is transferred, and transparent The microstructure mold 7 having the micrometer scale convex structure 72 formed by transferring the micrometer scale concave structure 44 on the surface of the structure is obtained.

  The transparent thin film has a role of integrating as a transparent structure so that the cured thick film photoresist can be peeled and removed without being left like an isolated island, and the light shielding pattern 2 is not destroyed in the peeling process after the electroforming method. Playing a role.

  The electroforming method is a method of depositing a metal and laminating a metal layer by electroplating or electroless plating. Examples of the metal include copper, nickel, gold, silver, nickel-cobalt alloy, and the like. . In order to electroform the cured thick film photoresist layer 41, it is necessary to subject the cured thick film photoresist layer 41 to a conductive treatment. For the conductive treatment, any conventionally known method may be employed. Examples include an electrolytic plating method and an ion sputtering method.

  The structure of the manufacturing method of the microstructure mold of the present invention is as described above, and a mold having both a nanometer-scale microstructure and a micrometer-scale concave structure can be easily obtained with high accuracy.

  Next, although an example of the present invention is given and explained in detail, the present invention is not limited to the following example.

Example 1
A quartz substrate with a chromium mask pattern having a thickness of 1.2 mm was used as the transparent substrate 1 having a micrometer-scale light-shielding pattern formed on one surface. Photoresist (trade name “SU-8”, manufactured by Kayaku Macrochem Co., Ltd.) was applied to the surface of the transparent substrate 1 on which the light-shielding pattern 2 was formed, and a photoresist layer having a thickness of 3 μm was laminated. After pre-baking at 95 ° C. for 8 minutes, the entire surface of the photoresist layer was irradiated with ultraviolet rays of 13 W / cm ² for 30 seconds, post-baked at 65 ° C. for 1.5 minutes and 95 ° C. for 6.5 minutes, and 150 The transparent thin film 3 made of a cured transparent thin film photoresist was formed by hard baking at 2.5 ° C. for 2.5 minutes.

  On the transparent thin film 3, a photoresist (trade name “SU-8”, manufactured by Kayaku Macrochem Co., Ltd.) is applied by spin coating, and an uncured thick film photoresist layer 4 having a thickness of 100 μm is laminated. Prebaked for 5 minutes and at 95 ° C. for 8 minutes.

  A quadrangular pyramid-shaped concave portion having a side of 200 nm was formed at an interval of 400 nm in a 200 μm square area by anisotropic etching on a 500 μm thick silicon substrate to obtain a substrate (b) 5. The obtained substrate (b) 5 is laminated on the unbaked thick film photoresist layer 4 having a thickness of 100 μm that has been pre-baked, and pressed to intrude the photoresist into the quadrangular pyramid-shaped concave portion, thereby forming the quadrangular pyramid-shaped concave portion. Was transferred to the uncured thick film photoresist layer 4.

Next, the uncured thick film photoresist layer 4 is irradiated with ultraviolet rays of 13 W / cm ² from the transparent substrate 1 side for 30 seconds, post-baked at 65 ° C. for 1.5 minutes and 95 ° C. for 6.5 minutes, A hard baked photoresist layer 41 was formed by hard baking at 150 ° C. for 2.5 minutes.

  After the substrate (b) 5 is peeled off from the cured thick film photoresist layer 41, the uncured photoresist 42 in the cured thick film photoresist layer 41 that has been shielded from light by the light shielding pattern during UV irradiation is removed from the photoresist developer (Kayaku Macrochem Corporation). The product was washed and removed with a trade name “developer for SU-8”) to form a concave structure 44 on a micrometer scale.

  After peeling off the transparent substrate 1, nickel was sputtered onto the cured thick film photoresist layer 41 using a sputtering apparatus, and a conductive seed layer was laminated. Next, after electroforming nickel by electrolytic nickel plating on the conductive seed layer and laminating the metal (nickel) layer 6, the metal (nickel) layer 6 is peeled off from the cured thick film photoresist layer 41 to obtain a nanometer scale. A microstructure die 7 having a square pyramid-shaped concave portion 71 and a micrometer-scale convex structure 72 was obtained.

  The nickel plating solution for performing nickel electroforming is nickel sfamate tetrahydrate 450 g / L, nickel chloride hexahydrate 10 g / L, boric acid 30 g / L, and surface surface force adjusting agent 20 ml / L. The bath temperature was 50 ° C. and the pH was 4.

It is sectional drawing which shows the 1st process of this invention. It is sectional drawing which shows the 2nd process of this invention. It is sectional drawing which shows the 2nd process of this invention. It is sectional drawing which shows the 3rd process (3) of this invention. It is sectional drawing which shows the 3rd process (3) of this invention. It is sectional drawing which shows the 3rd process (3) of this invention. It is sectional drawing which shows the 4th process (4) of this invention. It is sectional drawing which shows one example of the microstructure metal mold | die obtained with the manufacturing method of the microstructure metal mold | die of this invention.

Explanation of symbols

1 Transparent substrate (I)
2 Light-shielding pattern 3 Cured transparent thin film photoresist layer 4 Uncured thick film photoresist layer 5 Substrate (b)
6 Metal layer 7 Microstructure mold

Claims (5)

(1) a first step of forming a transparent thin film having a thickness of 10 nm to 10 μm on a transparent substrate (a) having a micrometer-scale light-shielding pattern formed on one surface;
(2) On the transparent thin film, a photoresist is applied in a thickness of 5 μm to 5000 μm to form an uncured thick film photoresist layer, and then a nanometer-scale microstructure is formed in the uncured thick film photoresist layer. A second step of laminating and pressing the substrate (b)
(3) After exposing from the other surface of the transparent substrate (a) to cure the uncured thick film photoresist layer to form a cured thick film photoresist layer, the substrate (b) is peeled off, and then cured thick film photoresist A third step of cleaning away the uncured photoresist of the layer to form a micrometer scale concave structure; and
(4) After a metal layer is laminated by electroforming on the surface of the cured photoresist layer on which the nanometer-scale microstructure transfer structure and the micrometer-scale concave structure are formed, the photoresist is peeled off from the metal layer. The manufacturing method of the microstructure metal mold | die characterized by consisting of these processes.   2. The method for producing a microstructure mold according to claim 1, wherein the width and height of the nanometer-scale microstructure are 10 to 1000 nm.   The method for producing a microstructure mold according to claim 1 or 2, wherein the micrometer-scale concave structure has a width and height of 5 to 5000 µm.   The method for producing a microstructure mold according to claims 1 to 3, wherein the transparent thin film is a cured photoresist film.   The width of the nanometer-scale microstructure is smaller than one-half wavelength of the light that hardens the photoresist, and the height of the microstructure is more than one-half wavelength. The method for producing a microstructure mold according to claim 1, wherein the substrate (b) is transparent to light for curing the photoresist.

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