JP2005256110A - Structure of die for electroforming and production method therefor and electroforming method using the die for electroforming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a die for electroforming with which a component having high shape accuracy and dimensional accuracy is produced, and to provide an electroforming method using the die for electroforming. <P>SOLUTION: The die for electroforming is composed of: a die structure made of silicon and having almost vertical side walls formed by dry etching; insulators for covering the side walls and the upper face of the die structure; a supporting substrate for supporting the die structures; and insulating connection layers for physically connecting the die structure and the supporting substrate, and has recessed parts each formed in such a manner that at least a part of the section at which the die structure is not formed is removed in the insulating connection layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of a mold used in an electroforming method, and a method of electroforming, and in particular, a structure and a manufacturing method of an electroforming mold used for manufacturing a fine part with a high aspect ratio, and The present invention also relates to an electroforming method using the electroforming mold.

  The electroforming method is widely used as a processing method suitable for manufacturing parts and molds having fine shapes.

  As a conventional electroforming mold, a structure is disclosed in which a mold structure is formed by crystal anisotropic wet etching using an alkaline etchant on a silicon wafer, and an energization film is formed on the entire surface of the mold structure.

  As shown in FIG. 7, in the electroforming mold disclosed in Patent Document 1, a photoresist 63 is applied to an oxide film 62 on a silicon wafer 61, a pit pattern is exposed using laser light, and photolithography is performed. The oxide film 62 is patterned by the process, and after the photoresist 63 is peeled off, pits 64 are formed by anisotropic wet etching using an alkaline etchant. After the oxide film 62 is removed, nickel is used as a current-carrying film 65 on the master disk. After forming the master by forming it on the entire surface where the pits 64 are formed, a stamper 66 made of nickel is manufactured by electroforming.

  As shown in FIG. 8, in Patent Document 2, after forming an electroforming mold 71 having a high aspect ratio using anisotropic wet etching on a substrate made of silicon or quartz, sputtering is performed as an energizing film 72. Thus, nickel is formed on the entire surface of the structure formed by anisotropic wet etching, and the mold 73 is formed by transferring the shape of the electroforming mold by electroforming.

  In addition, as a conventional electroforming mold, a configuration is disclosed in which a mold structure made of a photoresist is formed on a conductive substrate.

As shown in FIG. 9, the electroforming mold disclosed in Patent Document 3 includes an exposure step of irradiating a photosensitive insoluble material 81 coated on a conductive substrate 82 with ultraviolet rays through a mask 83. The mold structure 84 is formed by a development process in which only an unexposed portion of the photosensitive insoluble material 81 that has not been exposed to ultraviolet rays is dissolved and removed, thereby producing an electroforming mold. The thickness of the photosensitive insoluble material 81, that is, the mold structure 84 is as thick as about 60 μm (see, for example, Patent Documents 1 to 3).
JP-A-5-12722 Japanese Patent Laid-Open No. 5-4232 JP 2003-119588 A

  However, in Patent Document 1, because of the die processing utilizing the crystallinity of Si, the shape in the plane direction that can be produced is mainly rectangular, and it is difficult to produce a shape such as a free curve or a circle. There was a problem with low degree of freedom.

  Further, when electrodes are formed on both the bottom and side surfaces of a rectangular hole as shown in Patent Document 2 and electroforming is performed, a metal film grows from both the bottom and side surfaces of the hole. As the electroforming progresses, the hole diameter becomes smaller, it becomes difficult for the electrolyte to enter and exit, the film formation rate decreases, and the parts or molds produced by electroforming become uneven. In addition, there is a problem that the hole is blocked by the metal deposited on the upper part of the hole, and a hollow portion is formed in a part or mold produced by electroforming.

  In Patent Document 3, since the crystallinity of Si is not used, the shape that can be created is high, but the resist is exposed to ultraviolet light to produce a mold. Due to the influence, the edge of the rectangular pattern of the resist structure becomes round or light diverges in the depth direction, so that the perpendicularity of the resist structure is lowered. For this reason, there existed a problem that the desired shape of the components and molds manufactured by electroforming could not be obtained, or the dimensional accuracy was lowered.

  The present invention has been made in view of the above problems, and an object thereof is to provide an electroforming mold capable of producing a part having high shape accuracy and dimensional accuracy and an electroforming method using the electroforming mold. And

Therefore, in the present invention, a plurality of mold structures formed on a substrate and made of silicon having sidewalls substantially perpendicular to the substrate surface, an insulator covering the sidewalls and the upper surface of the mold structure, and an insulating connection layer are provided. The insulating connection layer connects the lower surface of the mold structure and the upper surface of the support substrate, and at least part of the portion of the insulating connection layer that is not in contact with the mold structure is removed. An electroforming mold characterized by having a concave portion formed by the above method.
Further, the electroforming mold is characterized in that the supporting substrate is an N-type silicon substrate. Further, the electroforming mold is characterized in that the supporting substrate is a P-type silicon substrate. Further, the electroforming mold is characterized in that the supporting substrate has a doped area doped with impurities, and a window capable of electrical connection is formed in the doped area. Further, the electroforming mold is characterized in that the dope area is formed on a surface opposite to the surface on which the mold structure of the support substrate is formed. In addition, the electroforming mold is characterized in that the dope area is formed on the upper surface of the support substrate, and at least one of the recesses of the insulating connection layer is a window. In addition, the electroforming mold is characterized in that the concave portion of the insulating connection layer is a character, a pattern, or a combination thereof. Further, the electroforming mold is used, and electrical connection is made with at least one portion of the support substrate, current is passed through the support substrate, and a metal is grown from the concave portion of the insulating connection layer. The electroforming method was used. Further, the electroforming method is characterized in that electrical connection is made with at least one of the dope areas.

A step of forming an electrode on a part of the support layer of the substrate comprising the support layer, the oxide film layer on the upper surface of the support layer, and the active layer on the upper surface of the oxide film layer; and a surface of the active layer in contact with the oxide film layer The process of forming a thermal oxide film on the opposite surface, the process of forming a mask using the thermal oxide film using photolithography, the process of etching the active layer, and the insulating film formed on the surface exposed by etching of the active layer A step of forming a resist pattern on the surface of the insulating film opposite to the surface in contact with the active layer, and a through-hole penetrating the upper and lower surfaces of the oxide film layer in a part of the exposed surface of the oxide film layer The method for manufacturing an electroforming mold is characterized by having a process of forming a resist and a process of removing a resist pattern. In addition, the electroforming mold manufacturing method is characterized in that the electrode is a doped area formed by introducing impurities into the support layer. The dope area is exposed on the surface of the support layer. The dope area is formed on the surface of the support layer opposite to the surface in contact with the oxide film layer. The dope area is exposed in the through hole, and the electroforming mold manufacturing method is provided. The electroforming mold manufacturing method is characterized in that the supporting layer is a silicon supporting substrate, the oxide film layer is a silicon dioxide BOX layer, and the active layer is a Si active layer.
Further, a support base, an insulating layer formed on the upper surface of the support base, a through-hole penetrating the upper surface of the insulating connection layer opposite to the lower surface in contact with the support base, and formed on the upper surface of the insulating connection layer The electroforming mold is characterized by having a plurality of mold structures thus formed and an insulator covering the surfaces of the mold structures facing each other.

  Therefore, it is possible to manufacture an electroforming mold using silicon produced by a processing method with high accuracy and a high degree of freedom of shape, and it is possible to deposit metal from the bottom surface of the mold by electroforming.

  Therefore, according to the present invention, it is possible to produce a part or mold with good shape accuracy and dimensional accuracy. Moreover, when the shape seen from the upper surface of the hall is a character or design such as a company name, a product name, or a logo, the decorativeness of the electroformed part is improved, and high value-added parts and molds can be provided.

  FIG. 1 is a cross-sectional view of an electroforming mold 100 according to Embodiment 1 of the present invention. The electroforming mold 100 includes a support substrate 3, an insulating layer 2 formed on the support substrate 3, a mold pattern 1 formed on the insulating layer 2, and an insulator 4 formed so as to cover the mold pattern 1. The hole formed in the insulating layer 2 is composed of a doped area 6 formed on the surface opposite to the surface on which the mold pattern 1 of the support substrate 3 is formed, and an insulator 5 covering a portion other than the doped area 6. 7 is formed. The material of the mold pattern 1 is silicon. The insulating layer 2, the insulator 4, and the insulator 5 are insulators such as silicon dioxide and silicon nitride. Further, the support substrate 3 is n-type silicon or p-type silicon, and the doped area 6 is formed on the support substrate 3 with phosphorus, boron, arsenic by an impurity introduction method such as ion implantation or sealed tube diffusion. This is a portion formed by introducing impurities such as and redistributing the impurities by thermal diffusion. The thickness of the support substrate 3 is 200 μm or more and 1 mm or less. The thickness of the insulating layer 2 is several tens of nm or more and 20 μm or less. The thickness of the mold pattern 1 is several μm or more and several mm or less. Moreover, the angle of the side wall of the mold pattern 1 is approximately 90 degrees. Moreover, the thickness of the insulator 4 is 1 μm or less, and may be several tens of nm or more in order to prevent dielectric breakdown during the electroforming process described later.

  FIG. 2 is a diagram illustrating a method for manufacturing the electroforming mold 100 according to Embodiment 1 of the present invention. First, as shown in FIG. 2A, as a start substrate, a support layer 23, a buried oxide film layer (hereinafter referred to as a BOX layer) 22 formed on the support layer 23, and a BOX layer 22 are formed. An SOI (Silicon On Insulator) wafer made of the active layer 21 thus prepared is prepared. The material of the support layer 23 and the active layer 21 is silicon, and the material of the BOX layer 22 is silicon dioxide. The thicknesses of the support layer 23, the BOX layer 22, and the active layer 21 are the same as the thicknesses of the support substrate 3, the insulating layer 2, and the mold pattern 1, respectively.

  Next, as shown in FIG. 2B, a mask 24 is formed on the support layer 23 using a photolithography process. The material of the mask 24 is, for example, a photoresist or silicon dioxide. Thereafter, impurities such as phosphorus, boron, and arsenic are introduced into the support layer 23 from the mask 24 side by an impurity introduction method such as ion implantation or sealed tube diffusion. Thereafter, the mask 24 is removed, and a thermal oxide film is formed on the surfaces of the active layer 21 and the support layer 23. Since the thermal oxide film forming process is a process at a high temperature of 900 ° C. to 1100 ° C., the introduced impurities are diffused in the support layer 23 by the thermal oxidation process.

  Next, as shown in FIG. 2C, the thermal oxide film on the active layer 21 is patterned by a photolithography process to form a pattern mask 26. As an etching method used in the photolithography process, dry etching such as reactive ion etching (hereinafter referred to as RIE) or wet etching using hydrofluoric acid or buffered hydrofluoric acid is used. Further, the thermal oxide film on the support layer 23 is patterned by a photolithography process to form a window pattern 25, and a doped area 27 formed by diffusing impurities in the thermal oxidation forming process is exposed. The thickness of the mold pattern mask 26 is several hundred nm or more and several μm or less, and the thickness of the photoresist for forming the mold pattern mask 26 is several hundred nm or more and several μm or less. Compared to the photoresist thickness of several tens of μm used in Patent Document 3, the thickness of the photoresist used in the present invention is thin, so that the influence of light diffraction during exposure is small, and the photomask pattern is applied to the photoresist. It is possible to transfer with good shape accuracy and dimensional accuracy, and it is possible to transfer a photoresist pattern to the mold pattern mask 26 with high shape accuracy and dimensional accuracy.

  Next, as shown in FIG. 2D, the active layer 21 is patterned by dry etching. Here, as a method of processing the active layer 21, deep reactive ion etching (DRIE) which is dry etching is used. DRIE is a processing method that etches silicon while repeating the etching process and the protective film forming process on the side wall, and is an apparatus that can process silicon with a high aspect ratio. The aspect ratio of the silicon pattern formed by DRIE processing is about 20 at the largest. In addition, since DRIE is a method of processing in the depth direction while protecting the sidewall of the etching shape, the active layer 21 has a pattern with a high aspect ratio obtained by transferring the pattern of the mold pattern mask 26 with high shape accuracy and dimensional accuracy. Become.

  Next, as shown in FIG. 2E, the insulating film 28 is formed on the surface of the active layer 21 patterned by a method such as chemical vapor deposition (CVD), sputtering, or thermal oxidation. When the insulating film 28 is formed by thermal oxidation, the insulating film 28 is also formed on the surface of the support layer 23. After that, a pattern equivalent to the window pattern 25 is formed by performing a photolithography process. Can do. The material of the insulating film 28 is an insulator such as silicon dioxide or silicon nitride.

  Next, as shown in FIG. 2F, a resist pattern 29 is formed on the insulating film 28 using a photolithography process. The photoresist for forming the resist pattern 29 is applied using a method such as spin coating or spray coating. In order to apply the photoresist to the sidewall of the insulating film 28 with good uniformity, spray coating is desirable as a method for applying the photoresist. In the exposure step, a contact mask aligner may be used, or exposure may be performed by focusing on the vicinity of the BOX layer 22 using a projection exposure type aligner. Alternatively, the photoresist may be exposed by a direct drawing method in which the photoresist is directly irradiated with a laser beam or an electron beam.

  Next, as shown in FIG. 2G, holes 7 are formed by a method such as dry etching such as RIE or plasma etching or wet etching using a hydrofluoric acid aqueous solution or buffered hydrofluoric acid, and a resist pattern 29 is formed. The electroforming mold 100 can be formed by removing.

  FIG. 3 is a diagram for explaining an electroforming process using the electroforming mold 100 according to Embodiment 1 of the present invention. The electrocasting iron 11 is filled with the electroforming solution 10, and the electroforming mold 100 and the electrode 9 are immersed in the electroforming solution 10. The electroforming solution 10 varies depending on the metal to be deposited. For example, when nickel is deposited, an aqueous solution containing nickel sulfamate hydrate is used. The material of the electrode 9 is substantially the same material as the metal to be deposited. When nickel is deposited, nickel is used, and a nickel plate or a nickel basket with a nickel ball is used as the electrode 9. The material deposited by the production method of the present invention is not limited to nickel. The present invention is applicable to all materials that can be electroformed, such as copper (Cu), cobalt (Co), and tin (Sn). The dope area 6 and the electrode 9 of the electroforming mold 100 are connected to a power source V. Since the doped area 6 is formed, the power supply V and the support substrate 3 are in ohmic contact, and stable current supply can be performed. In addition, when the resistance value of the support substrate 3 is small enough to make an ohmic contact with the power supply V, the doped area 6 is not necessarily required. A current flows through the support substrate 3 due to the voltage of the power supply V, and electrons are supplied from the holes 7, whereby metal is gradually deposited from the holes 7. The deposited metal grows in the thickness direction of the support substrate 3 and also grows in a direction perpendicular to the thickness direction of the support substrate 3.

  FIG. 4 is a diagram for explaining an electroformed component 8 produced using the electroforming mold 100 according to Embodiment 1 of the present invention. Thereafter, the deposited metal grows along the mold pattern 1 surrounded by the insulator 4, and finally becomes an electroformed component 8 shown in FIG. After the completion of the electroforming, as shown in FIG. 4B, the electroformed part 8 is taken out from the electroforming mold 100 to obtain the electroformed part 8. In order to obtain a desired part thickness, the electroformed part 8 may be polished. Further, the convex portion corresponding to the shape of the hole 7 may be removed by polishing. Moreover, the shape seen from the upper surface of the hole 7 may be a character or design such as a company name, a product name, or a logo.

  As described above, according to the electroforming mold 100 described in the first embodiment of the present invention, it has a high aspect ratio and a high aspect ratio processed by DRIE which is dry etching with a high degree of freedom in manufacturing shape. Since silicon can be used as a mold and metal can be deposited from the bottom surface of the mold by electroforming, it is possible to manufacture parts and molds with good shape accuracy and dimensional accuracy. In addition, when the shape of the hole 7 viewed from the top is a letter or design such as a company name, product name, logo, etc., the decorativeness of the electroformed part 8 is improved and high value-added parts and molds are provided. it can.

  In the above description, the electroformed mold 100 is used to obtain the electroformed part 8. However, a metal is deposited by an electroforming method, and the shape made of the metal can be used as a mold and made of a resin. A part may be formed.

  FIG. 5 is a view for explaining an electroforming mold 200 according to Embodiment 2 of the present invention. In addition, about the same component as the electroforming mold 100 demonstrated in Embodiment 1, the same code | symbol is used and description is abbreviate | omitted. In the electroforming mold 200, the precipitation preventing layer 31 is formed on the point where the doped area 6 is formed under the hole 7 and on the surface opposite to the surface on which the mold pattern 1 of the support substrate 3 is formed. This is a point different from the electroforming mold 100.

  FIG. 6 is a diagram illustrating an electroforming process using the electroforming mold 200 according to Embodiment 2 of the present invention. At least one of the dope areas 6 is connected to the power source V. A current flows through the support substrate 3 due to the voltage of the power supply V, and electrons are supplied from the holes 7, whereby metal is gradually deposited from the holes 7.

  The precipitation preventing layer 31 is an insulator such as silicon dioxide or silicon nitride. Further, when the support substrate 3 is n-type silicon, the precipitation preventing layer 31 may be a layer in which p-type impurities are diffused. In this case, a pn junction is formed, and when the electroforming is performed, a reverse bias state is established, so that no metal is deposited on the deposition preventing film layer 31. Note that the deposition preventing layer 31 is not always necessary. When the deposition preventing layer 31 is not provided, the metal is deposited on the surface of the support substrate 3 opposite to the surface on which the mold pattern 1 is formed. The electroforming mold 200 can be electroformed in the same manner as the electroforming mold 100 by making an electrical connection from at least one of the holes 7.

  As described above, according to the electroforming mold 200 according to the second embodiment of the present invention, in addition to the effects described in the first embodiment, the components requiring patterning are only on one side of the substrate. Therefore, an electroforming mold can be easily obtained, and the production cost of the electroforming mold 200 can be reduced. Further, when the electroforming mold 200 has the deposition preventing layer 31, no metal is deposited on the surface of the support substrate 3 opposite to the surface on which the mold pattern 1 is formed. Therefore, since the consumption of the electrode 9 can be suppressed, electroforming can be performed for a long time, and the composition of the electroforming liquid 10 is stabilized, so that a metal having a stable composition can be deposited.

It is sectional drawing of the type | mold 100 for electroforming which concerns on Embodiment 1 of this invention. It is a figure explaining the manufacturing method of the type | mold 100 for electroforming which concerns on Embodiment 1 of this invention. It is a figure explaining the electroforming process using the type | mold 100 for electroforming which concerns on Embodiment 1 of this invention. It is a figure explaining the electroformed part 8 produced using the type | mold 100 for electroforming which concerns on Embodiment 1 of this invention. It is a figure explaining the die 200 for electroforming which concerns on Embodiment 2 of this invention. It is a figure explaining the electroforming process using the type | mold 200 for electroforming which concerns on Embodiment 2 of this invention. It is a figure explaining the prior art. It is a figure explaining the prior art. It is a figure explaining the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold pattern 2 ... Insulating layer 3 ... Supporting substrate 4 ... Insulator 5 ... Insulator 6 ... Dope area 7 ... Hole 8 ... Electroformed part

Claims (16)

A plurality of mold structures made of silicon formed on a substrate made of silicon and having sidewalls substantially perpendicular to the substrate surface;
An insulator covering the sidewall and upper surface of the mold structure;
A support substrate that supports the mold structure via an insulating connection layer;
The insulating connection layer connects the lower surface of the mold structure and the upper surface of the support substrate,
An electroforming mold comprising a recess formed by removing at least a part of a portion of the previous insulating connection layer that is not in contact with the mold structure.   The electroforming mold according to claim 1, wherein the support substrate is an N-type silicon substrate.   The electroforming mold according to claim 1, wherein the support substrate is a P-type silicon substrate.   The support substrate has a doped area doped with impurities, and a window capable of electrical connection is formed in the doped area. The electroforming mold described.   5. The electroforming mold according to claim 4, wherein the dope area is formed on a surface of the support substrate opposite to a surface on which the mold structure is formed.   The electroforming mold according to claim 4, wherein the doped area is formed on an upper surface of the support substrate, and at least one of the recesses of the insulating connection layer is the window.   The electroforming mold according to any one of claims 1 to 6, wherein the concave portion of the insulating connection layer is a character, a pattern, or a combination thereof.   The electroforming mold according to any one of claims 1 to 7, wherein the mold is electrically connected to at least one portion of the support substrate, a current is passed through the support substrate, and a metal is supplied from the recess of the insulating connection layer. An electroforming method characterized by growing.   The electroforming method according to claim 8, wherein electrical connection is made with at least one of the dope areas. Forming an electrode on a part of the support layer of the substrate comprising a support layer, an oxide film layer on the upper surface of the support layer, and an active layer on the upper surface of the oxide film layer;
Forming a thermal oxide film on the surface of the active layer opposite to the surface in contact with the oxide film layer;
Forming a mask of the thermal oxide film using photolithography;
Etching the active layer;
Forming an insulating film on a surface exposed by etching of the active layer;
Forming a resist pattern on a surface opposite to the surface in contact with the active layer of the insulating film;
Forming a through hole penetrating the upper surface and the lower surface of the oxide film layer in a part of the exposed surface of the oxide film layer;
A step of removing the resist pattern;
A method for producing an electroforming mold, comprising:   The method for manufacturing an electroforming mold according to claim 10, wherein the electrode is a doped area formed by introducing impurities into the support layer.   The method for manufacturing an electroforming mold according to claim 11, wherein the dope area is exposed on a surface of the support layer.   The method for manufacturing an electroforming mold according to claim 12, wherein the doped area is formed on a surface of the support layer opposite to a surface in contact with the oxide film layer.   The method for manufacturing an electroforming mold according to claim 12, wherein the dope area is exposed in the through hole.   15. The support layer according to claim 10, wherein the support layer is a silicon support substrate, the oxide film layer is a silicon dioxide BOX layer, and the active layer is a Si active layer. Manufacturing method of electroforming mold. A support base,
An insulating layer formed on the upper surface of the support base;
A through-hole penetrating a lower surface of the insulating connection layer that is in contact with the support base and an upper surface on the opposite side;
A plurality of mold structures formed on an upper surface of the insulating connection layer;
An insulator covering the surfaces of the mold structures facing each other;
An electroforming mold characterized by having

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