JP2007216523A - Method for manufacturing mold core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a mold core which can shorter a manufacturing time and to manufacture a high-accuracy mold core. <P>SOLUTION: A minute pattern 111 for a plurality of mold cores is formed at a pattern forming material 110 (b), and the pattern forming material 110 with the minute pattern for a plurality of the mold cores formed is joined to a mold material 120 (c). The pattern forming material 110 in a part where the minute pattern is not formed is removed. Each mold core, after being cut out cylindrically, is processed in a prescribed mold core shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a mold core used for molding optical parts and the like.

  Conventionally, optical parts such as diffraction gratings have been mass-produced by injection molding of resin or the like. At this time, a mold core having a fine pattern formed on the surface of its tip is used.

  FIG. 6 is a view showing the structure of a mold core used for molding an optical component. FIG. 2A is a perspective view showing the appearance of the mold core, and FIG. 2B is an enlarged sectional view of a fine pattern formed on the surface of the tip portion.

  As shown in FIG. 5A, the mold core 600 includes a large diameter portion 610 composed of a large diameter cylinder and a small diameter portion 620 composed of a small diameter cylinder, and the large diameter portion 610 is provided. The small-diameter portions 620 are stacked so that the centers coincide with each other. Further, a fine pattern 621 as shown in FIG. 5B is formed at the tip of the small diameter portion 620, and the fine pattern is transferred to the molded product. For example, the fine pattern 621 is formed in a circular region having a diameter of 2 mm so that the width of the convex portion and the concave portion is 9.6 μm, and the height of the convex portion (depth of the concave portion) is 0.8 μm.

  Such a mold core is manufactured by, for example, a nickel electroforming method (electroforming). That is, a desired fine pattern is formed in advance on a glass or single crystal silicon by using a lithography technique and an etching technique, and using this as a mother, a nickel lump is grown for a long time by nickel plating after electroless plating. Thus, a fine pattern is transferred, and a die core is manufactured by processing a nickel lump grown to a required size into a predetermined shape as shown in FIG.

  However, since the conventional nickel electroforming method forms a fine pattern by transfer from the mother, the accuracy deteriorates and nickel is piled up by electroplating to form a nickel lump. A plating process was required, and it was difficult to shorten the production time.

  Japanese Patent Laid-Open No. 2003-145546 (hereinafter referred to as Patent Document 1) discloses a method for manufacturing a mold core using electroforming. Japanese Patent Laid-Open No. 2005-262718 (hereinafter referred to as Patent Document 2) discloses that an optical transfer surface is etched by using a molding die capable of shortening the core manufacturing time as compared with the method described in Patent Document 1. A molding die in which the formed silicon material or glass material is fixed to the tip side of the die core is disclosed.

However, since the tip portion of the mold core used for molding of optical parts and the like is usually quite thin, it is difficult to ensure the flatness of the fixing surface by the method described in Patent Document 2, and furthermore, stress during bonding Therefore, it is difficult to manufacture a highly accurate mold core for optical parts by applying the method described in Patent Document 2.
JP 2003-145546 A JP 2005-262718 A

  An object of the present invention is to provide a mold core manufacturing method capable of reducing the manufacturing time and manufacturing a highly accurate mold core.

  The first mold core manufacturing method according to the present invention includes a plurality of mold cores formed on the surface of a flat pattern forming material made of a material that is easily processed by etching and difficult to machine. A fine pattern forming step for forming a fine pattern for each piece, a bonding step for bonding the pattern forming material on which the fine pattern is formed to a mold material, and removing the pattern forming material on a portion where the fine pattern is not formed A pattern forming material removing step, a cutting step of cutting out individual mold cores, and a shape processing step of processing individual mold cores cut out by the cutting step into a predetermined shape To do.

  In addition, the second mold core manufacturing method according to the present invention joins a plate-shaped pattern forming material made of a material that is easy to be finely processed by etching and difficult to machine to a mold material. Bonding step, forming a fine pattern for a plurality of mold cores on the surface of the pattern forming material bonded to the mold material, and forming a pattern in a portion where the fine pattern is not formed A pattern forming material removing step for removing a material, a cutting step for cutting out individual mold cores, and a shape processing step for processing individual mold cores cut out by the cutting step into a predetermined shape. It is characterized by.

  In this case, you may make it further have the smoothing process of smoothing the surface of the said pattern formation material between the said joining process and the said fine pattern formation process. Moreover, you may make it further have the 2nd joining process of joining another metal mold | die material to the said metal mold | die material after the said fine pattern formation process.

  Further, in the above case, in the pattern forming material removing step, the pattern forming material is removed at a portion where the fine pattern is not formed and which needs to be removed to machine each mold core. You may make it do. In the pattern forming material removing step, the pattern forming material may be removed by sandblasting, or the pattern forming material may be removed by laser light irradiation. The pattern forming material is made of, for example, silicon or glass. In the cutting step, individual die cores may be cut out by wire electric discharge machining. Moreover, in the said shape processing process, you may make it process in a predetermined shape by cutting or grinding.

  According to the present invention, the manufacturing time can be shortened and a highly accurate mold core can be manufactured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 and 2 are views for explaining a method of manufacturing a mold core according to the present invention.

  First, a pattern forming material 110 for forming a fine pattern as shown in FIG. As shown in FIG. 2A, the pattern forming material 110 has a thin (for example, about 30 μm to 2 mm) flat plate shape (in the example of FIG. 1, a disk shape). The size (area) of the pattern forming material 110 is sufficiently large (for example, about 100 mm in diameter) compared to the size of one mold core (for example, the diameter of the large diameter portion is about 11 mm). As will be described later, fine patterns corresponding to a plurality of mold cores are formed on the pattern forming material 110. The pattern forming material 110 is made of a material that can be easily processed by etching such as silicon or glass (for example, quartz glass), but is difficult to machine. Here, the material that is difficult to machine means a material that is difficult to cut or wire EDM, that is, a material that is hard and has low conductivity.

  Next, as shown in FIG. 2B, fine patterns 111 corresponding to a plurality of mold cores are formed on the pattern forming material 110 (a fine pattern forming step). For example, a fine pattern 111 for 25 mold cores is formed on a disk-shaped pattern forming material 110 having a diameter of about 100 mm. In addition, the space | interval between each fine pattern 111 has a space | interval more than one metal mold core (for example, 11.5 mm or more). The fine pattern 111 is formed using a normal lithography technique (for example, optical lithography or electron beam lithography) and an etching technique (for example, dry etching).

  Next, as shown in FIG. 2C, the pattern forming material 110 on which a fine pattern for a plurality of mold cores is formed is joined to a mold material 120 having the same size as the pattern forming material 110 (joining step). ). In general, a mold core for an injection molding machine needs to have a total length (height) of about 20 mm. Therefore, after a desired fine pattern 111 is formed on the pattern forming material 110, a plate thickness of about 20 mm is obtained. A plate material 120 having a thickness (in the example shown in the figure, a disk shape) is joined. The mold material 120 is made of a general mold material such as carbon steel, alloy tool steel, martensitic stainless steel, or the like. The pattern forming material 110 is bonded to the mold material 120 by, for example, brazing, surface activation bonding, or a conductive adhesive.

  Next, as shown in FIG. 2A, a portion of the pattern forming material 110 where the fine pattern is not formed is removed (pattern forming material removing step). As described above, since the pattern forming material 110 is made of a material that is difficult to machine, each die core cannot be cut out while the pattern forming material is bonded to the mold material 120. Therefore, in order to be able to cut out each mold core, etc., the pattern forming material of the part where the fine pattern is not formed and which needs to be removed to machine each mold core, Remove by sandblasting. In the example shown in FIG. 5A, all the pattern forming material where the fine pattern 111 is not formed is removed. Details of the pattern forming material removing step will be described later.

  Next, using a wire electric discharge machine or the like, each mold core is cut into a cylindrical shape 210 as shown in FIG. Further, each mold core cut out in a cylindrical shape is machined into a predetermined mold core shape 220 as shown in FIG. 4C by a cutting process or a grinding process (shape processing step). The small-diameter portion 221 composed of the mold material is processed to be slightly thicker than the small-diameter portion 222 composed of the pattern forming material in order to prevent a tool that performs cutting or the like from coming into contact with the pattern forming material. Is done.

  As described above, a mold core having a fine pattern formed on the tip is manufactured.

  In the mold core manufacturing method described above, the pattern forming material is bonded to the mold material after the fine pattern is formed on the pattern forming material. However, the pattern formation is performed before the fine pattern is formed on the pattern forming material. The material may be joined to the mold material.

  In this case, if a fine pattern is to be formed using a reduction projection exposure machine (stepper) or an electron beam exposure machine for ordinary semiconductor manufacturing, the plate thickness must be set to a predetermined value (for example, 2 mm) or less. . Therefore, first, a thin pattern forming material (for example, about 300 μm) is bonded to a thin mold material (for example, about 2 mm) (first bonding step), and then the case shown in FIG. Similarly, a fine pattern is formed. Then, a mold material of about 20 mm is further joined to form a predetermined mold core thickness (height) as in the case shown in FIG. In addition, when there is no plate | board thickness restriction | limiting in the apparatus etc. which are used for formation of a fine pattern, if the metal mold | die material which has a required thickness from the beginning is joined, it is not necessary to pile up a metal mold | die material. The subsequent steps are the same as those described with reference to FIG. In addition, after joining a pattern formation material and a metal mold | die material (1st joining process), if a plane wrap is once performed and a fine distortion is formed after removing joining distortion, a fine pattern will be formed more accurately. It becomes possible.

  Next, details of the pattern forming material removing step will be described.

  Here, sandblasting is used to remove the pattern forming material. For example, the pattern forming material is removed by spraying alumina or the like on the pattern forming material. At this time, in order to protect a portion where the fine pattern is formed (tip portion of the small diameter portion) and other necessary portions, a resist pattern is formed on the portion.

  FIG. 3 is a diagram illustrating an example of a resist sheet 300 used for protecting a portion where a fine pattern is formed in the pattern forming material removing step. The figure (a) shows a top view and the figure (b) shows a front view.

  As shown in FIG. 5A, the resist sheet 300 has a rectangular outer shape, and a fine pattern is formed at a position corresponding to each of the fine patterns for a plurality of mold cores formed on the pattern forming material. A resist pattern 310 is formed for protecting (covering) the pattern forming material in the formed portion.

  The resist pattern 310 is made of a resin-based adhesive substance, and adheres to a portion of the pattern forming material where the fine pattern is formed, thereby protecting the fine pattern from removal processing such as sandblasting.

  The resist sheet 300 is manufactured by printing a resist pattern 310 on a transparent release paper 301 by a method similar to screen printing of a printed board. A release sheet 302 is attached to the resist sheet 300 on which the resist pattern 310 is formed in order to protect the resist pattern 310 until it is actually attached to the pattern forming material.

  In order to attach the resist pattern 310 to the pattern forming material, the release paper 302 on the side to be applied to the pattern forming material is peeled off, the resist pattern 310 is aligned with the fine pattern on the pattern forming material, and then the resist pattern 310 is attached. Affix to the pattern forming material. Thereafter, the release paper 301 on the upper surface side is peeled off.

  FIG. 4 is a diagram illustrating a state in which a resist pattern is attached to a pattern forming material. The figure (a) shows a top view and the figure (b) shows a front view.

  As shown in the figure, a resist pattern 310 is attached to a portion of the pattern forming material 110 where a fine pattern is formed.

  Here, although the fine pattern is protected using a resist sheet, a resist film is formed on the pattern forming material by spin coating or the like, and a fine pattern is obtained using ordinary lithography technology and etching technology. A resist pattern for protecting the film may be formed on the pattern forming material. In this case, the resist pattern can be positioned with higher accuracy.

  Once the fine pattern and other necessary parts are protected with a resist pattern, the pattern forming material where the tool passes when the mold core is cut out is removed by sand blasting alumina or the like on the pattern forming material. . When the necessary pattern forming material is removed, the resist pattern is removed with a solvent.

  FIG. 5 is a diagram illustrating a state of the pattern forming material at the time when the pattern forming material removing step is finished. The figure (a) shows a top view and the figure (b) shows a front view.

  As shown in the figure, the pattern forming material 510 remains in the portion where the fine pattern 111 is formed, and the pattern forming material is removed in the portion where machining is performed to cut out the mold core and the like. Yes. In other words, because the pattern forming material has been removed for the part touched by tools such as the wire during wire electric discharge machining and the cutting tool during cutting, the pattern forming material composed of a material that is difficult to machine, There will be no obstacles when cutting out the mold core. In the example shown in the figure, all of the pattern forming material where the fine pattern 111 is not formed is removed, but only the minimum necessary for cutting out the mold core is removed. It may be.

  Here, the pattern forming material is selectively removed by sandblasting, but the pattern forming material may be selectively removed by laser beam irradiation. In this case, it is not necessary to protect the fine pattern with the resist pattern, and it is only necessary to appropriately control the laser beam irradiation trajectory so that only the portion to be removed is irradiated with the laser beam.

  Further, when the pattern forming material is very thin (for example, about 30 to 50 μm), the pattern forming material may be selectively removed by etching. In this case, a resist film is formed on the pattern forming material by spin coating or the like, and a resist pattern for protecting a fine pattern and other necessary portions is applied to the pattern forming material by using a normal lithography technique and an etching technique. To form.

  As described above, according to the present invention, since a fine pattern is directly formed on the pattern forming material bonded to the surface of the mold material, deterioration due to transfer can be prevented, and no electroplating step is required. Therefore, the manufacturing time of the mold core can be greatly shortened.

  Further, in the present invention, the pattern forming material having a plurality of sizes of the mold cores and the mold material are joined (that is, members having sufficient width are joined), so that the joining flatness is ensured. It becomes easy and it becomes possible to manufacture a highly accurate mold core. In addition, when a fine pattern is formed after the pattern forming material is bonded to the mold material, if the surface of the pattern forming material is smoothed (lapping processing, etc.) before forming the fine pattern, the bonding distortion As a result, the mold core with higher accuracy can be manufactured.

It is FIG. (1) for demonstrating the manufacturing method of the metal mold | die core by this invention. It is FIG. (2) for demonstrating the manufacturing method of the metal mold | die core by this invention. It is a figure which shows the example of a resist sheet. It is a figure which shows the state which affixed the resist pattern on the pattern formation material. It is a figure which shows the state of the pattern formation material in the time of a pattern formation material removal process being completed. It is a figure which shows the structure of a metal mold | die core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 110 Pattern formation material 111 Fine pattern 120 Mold material 210 Mold core cut out cylindrically 220 Mold core 221 processed into the predetermined shape 221 Small diameter part comprised by mold material 222 Fine structure comprised by pattern formation material Diameter part 300 Resist sheet 301, 302 Release paper 310 Resist pattern 510 Pattern forming material 600 Mold core 610 Large diameter part 620 Small diameter part 621 Fine pattern

Claims (8)

A fine pattern forming step for forming a fine pattern for a plurality of mold cores on the surface of a flat fine pattern forming material made of a material that is easy to etch and difficult to machine;
A bonding step of bonding the pattern forming material on which the fine pattern is formed to a mold material;
A pattern forming material removing step of removing a portion of the pattern forming material where the fine pattern is not formed;
A cutting process for cutting individual mold cores;
And a shape processing step of processing each die core cut out by the cut-out step into a predetermined shape. A joining step of joining a plate-shaped pattern forming material made of a material that is easy to be finely processed by etching and difficult to machine, to a mold material;
A fine pattern forming step of forming a fine pattern for a plurality of mold cores on the surface of the pattern forming material joined to the mold material;
A pattern forming material removing step of removing a portion of the pattern forming material where the fine pattern is not formed;
A cutting process for cutting individual mold cores;
And a shape processing step of processing each die core cut out by the cut-out step into a predetermined shape. The method for producing a mold core according to claim 2, further comprising a smoothing step of smoothing a surface of the pattern forming material between the joining step and the fine pattern forming step. The method of manufacturing a mold core according to claim 2 or 3, further comprising a second bonding step of bonding another mold material to the mold material after the fine pattern forming step. The pattern forming material removing step includes removing the pattern forming material in a portion where the fine pattern is not formed and which needs to be removed in order to machine individual mold cores. Item 5. A method for producing a mold core according to any one of Items 1 to 4. The method for manufacturing a mold core according to any one of claims 1 to 5, wherein the pattern forming material is removed by sandblasting in the pattern forming material removing step. The method for manufacturing a mold core according to claim 1, wherein in the pattern forming material removing step, the pattern forming material is removed by laser light irradiation. The method for producing a mold core according to claim 1, wherein the pattern forming material is made of silicon or glass.

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