JP2005154891A - Ion-implanted electroformed structural material and method of producing the structural material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion-implanted electroformed structural material in which the strength of an electroformed body can be easily improved, and to provide a method of producing the same. <P>SOLUTION: The ion-implanted electroformed structural material is made of an electroformed body 1 formed by electroforming and has an ion-implanted layer formed by implanting ions 2 into the electroformed body 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to an ion-implanted electroformed member and a method for manufacturing the same, and more specifically, to an ion-implanted electroformed member having an internal hardness higher than that of an ion-implanted layer on the surface thereof. Is.

  The LIGA (Lithographie Galvanoformung Abformung; Lithography Electroforming Molding) process is useful when producing a large amount of fine metal structures with high accuracy. The LIGA process using synchrotron radiation (SR) light, which has high directivity among X-rays, can perform deep lithography, and can process a structure with a height of several hundreds of micrometers with accuracy in the micron range. is there. That is, since it has the characteristics that a metal fine structure having a large thickness structure can be easily manufactured, application in a wide range of fields is expected.

The LIGA process is a processing technique that combines lithography, plating as electroforming, and mold. In the LIGA process, for example, a resist film is formed on a conductive substrate, and this resist film is irradiated with SR light through an absorber mask (reticle) having a pattern of a predetermined shape. By such lithography, a resist structure (resin mold) corresponding to the shape pattern (mask pattern) of the absorber mask is formed. A metal fine structure is obtained by depositing metal in the opening of the mask pattern by electroforming. By using this high-precision metal fine structure as a mold and producing a resin-made fine molded product by injection molding or the like, a micro device combining them can be obtained (for example, Non-Patent Document 1). reference).
Manabu Yasui, Yasuo Hirabayashi, Hiroyuki Fujita: Surface Technology, 2001, Vol.52, No.11 pp.734-737

  However, in the LIGA process, metals that can be formed by electroforming are limited to metals that can be plated, such as Ni, Fe, Co, and Ni-Fe alloys. When higher hardness and higher strength are required, there are cases where high hardness materials such as Ni-Mn alloys and Ni-W alloys are used in the past, but advanced technical capabilities are required for management of plating solutions, The scope of application is also limited.

  In addition, when the wear resistance of fine parts becomes a problem, a hard film can be formed on the surface by plating, PVD (Physical Vapor Deposition), CVD (Chemical Vapor Deposition), etc. Ensuring the adhesion between the component body and the film is a problem. In addition, when the shape is complicated, there may be a case where it is difficult to form a film on a shadowed portion or a fine concave portion during vapor deposition.

  On the other hand, according to electroforming using a molten salt without using an aqueous solution as an electroforming bath, it is possible to obtain an electroformed material such as Cr, Ti, and Mo having higher hardness than the current Ni-based alloys. However, the molten salt that can be used for the above-described metal electroforming is limited to a high temperature of 250 ° C. or higher. In lithography using a normal photoresist, the resist is deformed by heat and cannot be used. In addition, the molten salt has high hygroscopicity and reactivity, and thus has a limitation that it is necessary to perform electroforming in an inert gas environment.

  For this reason, there has been a demand for the development of an electroformed member formed by a general-purpose method and capable of easily improving the strength and a method for manufacturing the same.

  An object of this invention is to provide the ion implantation electroformed member which can improve the intensity | strength of an electroformed material easily, and its manufacturing method.

  The ion-implanted electroformed member of the present invention is an electroformed member having an ion-implanted layer formed by implanting accelerated ions into an electroformed material formed by electroforming.

  The member has an ion-implanted layer having a high strength on the surface, and a modulated structure in which the structure is refined is formed. As a result, the strength can be improved in the surface layer portion and the inside thereof.

  The method for producing an ion-implanted electroformed member of the present invention includes a step of forming an electroformed material and a step of accelerating and implanting ions into the electroformed material.

  By combining this process, it is possible to form a finely modulated structure inside the ion implantation layer on the surface.

  By using the ion-implanted electroformed member of the present invention and the manufacturing method thereof, the durability of the electroformed member can be easily improved. For this reason, in addition to the micro electroformed member for micro equipment, conventionally, it is possible to omit the forging process by using the electroformed member generally requiring forging to improve the strength.

  It is not known why the ion hardness is increased when ions are implanted into the electroformed material. The present inventors searched various documents, but have not been able to confirm the fact that this phenomenon has been announced so far. However, the reproducibility was certain though the confirmation experiment was carried out by changing the experimental conditions.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining a method for manufacturing an ion-implanted electroformed member according to an embodiment of the present invention. Ions 2 accelerated by a voltage of 10 kV or more are implanted into an electroformed material 1 formed on a metal substrate 3 according to a resist pattern (not shown), and ions are implanted. By this ion implantation, as shown in FIG. 2, the hardness of the inner position from the ion implanted layer increases. This increase in hardness is significant, typically 30% and 50% higher than the untreated value. In FIG. 2, the ion implantation layer is formed in a depth of 5 μm or less, but the hardness in the range of this ion implantation layer is not shown.

  FIG. 3 is a schematic diagram of the microstructure of the electroformed material. It is possible to refine the structure even with an electroformed material. That is, when a pulsed voltage is applied between the electrodes in the electroforming bath and a pulsed current is applied to perform electroforming, when the electroformed material is precipitated from the electroforming liquid, the density of nucleation sites of precipitation is reduced. As a result, an electroformed material having a fine structure can be obtained. The schematic diagram of FIG. 3 is a schematic diagram of an electroformed material having such a fine structure. In the case of electroformed material, crystals grow continuously from the electrode surface, so long columnar crystals may be formed in the growth direction peculiar to the cast metal, and equiaxed crystals with no directionality may be formed. There is also. The schematic diagram in FIG. 3 may be interpreted as an equiaxed crystal or a cross section of a columnar crystal. In the case of columnar crystals, the average particle size is a particle size measured in a cross section in the longitudinal direction of the column.

  Between the fine crystal grains 5 in the structure shown in FIG. 3, voids 4 (also referred to as cavities or pores) unique to the electroformed material are generated. On the other hand, in the modulated structure refined inside the ion-implanted layer, as shown in FIG. 4, the crystal grain 5 is made finer than the crystal grain as it is electroformed, and the void 4 becomes smaller accordingly. Looks like. Imperfections (defects) such as voids appear to be partially consumed due to the increase in crystal grain boundaries, which is a kind of imperfections (defects), due to the refinement of crystal grains. However, as mentioned above, it is thought to be the first phenomenon encountered in the very long history of bulk metal materials, so we refrain from affirming it. The above description should be construed as stating the fact that it looks like that.

  FIG. 5 is a view showing a FIB (Focused Ion Beam) photograph of the electroformed material. FIG. 6 is a diagram in which the structure of the portion A in FIG. 5 is drawn. The electroformed material is formed as columnar crystals, and the average grain size of the columnar crystals is smaller than 1 μm. Although voids are generated in the electroformed material, the magnification is insufficient in FIG. 5 and cannot be observed.

  FIG. 7 is a view showing a FIB photograph showing the structure after ions are implanted from the surface side of the electroformed material, and FIG. 8 is a line drawing of a portion A corresponding to A in FIG. As can be seen by comparing FIG. 6 and FIG. 8 of the line drawing, the structure is modulated and refined at a position inside the inside of 40 μm from the surface, that is, inside the ion does not reach. As seen in FIG. 8, the modulation is influenced by the original columnar crystals and appears to be miniaturized while having a slightly elongated shape along the long direction of the columnar crystals. The degree of miniaturization is remarkable, and the average particle diameter seems to be considerably smaller than 0.5 μm.

  As described above, it is considered that the above-described increase in hardness can be obtained by the refined modulation structure obtained inside from the ion-implanted layer.

Using a 10 cm square nickel plate as the cathode and nickel as the anode, plating (electroforming) was performed for 100 minutes at a temperature of 55 ° C. and a current value of 5 A with the composition of the plating bath (electroforming liquid bath) shown below.
<Plating bath>
Nickel sulfamate: 300 g / l (g / dm ³ )
・ Manganese sulfamate: 40 g / l
・ Primary brightener (sodium saccharinate): appropriate amount ・ Secondary brightener (butynediol): appropriate amount ・ Surfactant (sodium lauryl sulfate): appropriate amount Next, cut out the center 2cm square part of this sample (electroformed material) Then, it was bisected into 1 cm widths on the left and right sides. (1) One was used for investigation of hardness and crystal grain size, and (2) the other was used for ion implantation.

  Hardness is measured by embedding the sample vertically in an epoxy resin so that the cross-section of the sample is flush with the surface of the resin, and after changing the cross-section up to the grain size # 4000 of the abrasive grains, After finishing and making the section a mirror surface, N = 10 was measured with a Vickers hardness meter at a point 25 μm from the plating surface side of the sample and averaged. The crystal grain size was measured by X-ray diffraction.

Next, the omnidirectional ion implantation treatment was performed on the sample (electroformed material) of (2) under the following conditions.
<All-direction ion implantation processing conditions>
・ Voltage: 30kV
・ Implanted ion species: Carbon (C)
・ Pulse frequency: 150 kHz
・ Processing time: 60 minutes ・ Achieved vacuum: 6.7 × 10 ⁻⁴ Pa or less ・ Temperature: Cooling the substrate holder with 25 ° C. cooling coolant After ion implantation, the Vickers hardness and crystal grain size were investigated in the same manner as in (1) above. .

(Survey results)
The Vickers hardness of the above (1) was Hv439, and the crystal grain size was in the range of 10 nm to 1000 nm. Further, in the SIM (Scanning Ion Microscopy) observation after the FIB processing, fine voids of nanometer order were confirmed.

  On the other hand, the ion-implanted ion-cast electroformed member was improved to Vickers hardness Hv511 inside the ion-implanted layer. The crystal grain size was also reduced to 5 nm to 250 nm. Further, in the SIM observation after the FIB processing, it was observed that the voids seen in the above (1) were reduced and the density was drastically reduced.

  Next, the knowledge obtained from other examples of the present invention including the above-described examples will be described enumerated.

  1) An ion-implanted layer is formed in a surface layer portion having a depth range of 5 μm or less from the surface of the ion-implanted electroformed member, and a microstructure whose microstructure is modulated is generated at a position deeper than the ion-implanted layer.

  The above-mentioned microstructure in which the microstructure of the electroformed material is modulated refers to a structure in which the microstructure as it is electroformed changes and the crystal grains that are finer than the crystal grains as electrocast are mainly used. . With this structure, it is possible to obtain a micro member having excellent durability. Implanting ions from the surface to a depth of more than 5 μm requires an enormous scale acceleration device, which deviates from the object of the present invention to easily increase the strength.

  The modulation of the microstructure may occur at the position of the center of the cross section that enters from the surface of the electroformed member.

  It has not been elucidated as described above why the above-mentioned modulated tissue is generated by ion implantation and to what depth it is formed from the surface. However, a modulation structure is formed over the entire thickness of the electroformed member having a thickness of about 80 μm. If this modulation texture occurs, it may be generated in the entire cross section, and the depth distribution of the modulation texture may not be controlled. However, if a miniaturized modulation structure is formed at least at the center of the cross section, it is very beneficial for improving the durability of the electroformed member.

  2) Further, according to the present invention, the average crystal grain size of the portion where the above-mentioned microstructural modulation occurs can be made 0.5 μm or less.

  By making the modulation structure finer in this way, the strength can be improved. As shown in FIGS. 5 to 8, when the structure of the electroformed material having a columnar crystal structure is modulated, the columnar crystal is succeeded while being refined. In the columnar crystal, the average crystal grain size is the average grain size in the cross section in the length direction of the columnar crystal.

  As described above, the present invention is formed by electroforming at a position deeper than the ion-implanted layer by electroforming the microstructure where the microstructure is modulated and the average crystal grain size is reduced. It can be made harder than the hardness of the electroformed material at that time.

  3) The electroformed material formed by electroforming is a material before ion implantation. The finer the structure of the electroformed material itself, the easier it is to generate a modulated structure by the ion implantation. The ion-implanted modulation structure is made finer and stronger than the electroformed material.

  The average grain size of the crystal grains of the electroformed material formed by electroforming is preferably 1 μm or less. In the case of columnar crystals, this average particle size is also the average value of the particle sizes in the cross section of the columnar crystals. The means can be achieved by a method of applying a voltage in pulses during electroforming. Thus, by applying a pulsed voltage, that is, supplying a pulsed current, it is possible to increase the degree of supersaturation during precipitation from the solution to increase the nucleation density and to refine the structure of the electroformed material.

  This operation makes it easier to form a finer modulation structure inside the ion-implanted layer when ion implantation is performed.

  4) In the step of ion implantation, ions can be implanted in a range of 5 μm or less from the surface, and thereby the internal hardness can be increased.

  In other words, since a finer modulation structure can be formed inside the ion-implanted layer, the strength is improved even in the inside where ions do not reach.

  In the above-described ion implantation step, ions are implanted in a range of 5 μm or less from the surface, and a tissue modulated to the internal tissue can be obtained.

  By this method, even if the ion-implanted layer is formed at 5 μm or less immediately below the surface, for example, a finely modulated structure can be formed inside the surface by 40 μm.

  5) In the ion implantation step, the temperature of the electroformed material may be (1/3) or less of the melting point (K) of the material constituting the electroformed material.

  Under these conditions, each crystal grain of the refined modulation structure can be kept in a refined state, and the grains can be prevented from growing larger and coarsening.

  6) In the ion implantation step, it is preferable to accelerate the ions with a voltage of 10 kV or more.

  When the acceleration voltage of ions is less than 10 kV, ion implantation cannot be sufficiently performed, and it is possible to form a finely modulated structure inside, but it is difficult.

  7) In the ion implantation step, it is preferable to use an omnidirectional plasma ion implantation apparatus.

  With this apparatus, an ion-implanted layer can be uniformly formed on all surfaces without creating a shadowed portion on the electroformed material having a complicated shape. Therefore, it is possible to form a miniaturized modulation structure without leakage from the ion implantation layer.

  8) It is preferable that the electroforming material is selected from Ni, Fe, Cu, Zn, Sn, Mn, Co, Ag, Au, or an alloy in which these are combined. By performing ion implantation treatment on these electroformed materials, ion implanted electroformed members having excellent durability can be produced.

  9) In the above embodiment, carbon (C) is used as ions implanted into the electroformed material, but other ions may be used. For example, nitrogen (N) ions can be used. The ions may be atomic ions or molecular ions. Needless to say, ions other than carbon and nitrogen may be used.

  As mentioned above, although the Example of this invention was described, the Example of this invention disclosed above is an illustration to the last, Comprising: The scope of the present invention is not limited to these Examples. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  By using the ion-implanted electroformed member and the manufacturing method thereof of the present invention, the durability of the electrodeposition material can be easily improved. Therefore, in addition to the micro electroformed member for micro equipment, conventionally, the strength is increased. Therefore, the presently unknown uses such as omitting the forging process using electroforming members generally requiring forging and the like are found, and a wider use is expected.

It is a figure explaining the method to manufacture the ion implantation electroformed member which is embodiment of this invention. It is a figure which shows the hardness distribution in the depth direction of the ion implantation electroformed member of this invention. It is a schematic diagram which shows the microstructure of the material as electroformed. It is a schematic diagram which shows the microstructure after performing ion implantation to an electroformed material. It is a figure which shows the FIB photograph of the position of 40 micrometers depth from the surface of the material as electroformed. FIG. 6 is a diagram in which the microstructure of part A in FIG. 5 is drawn. It is a figure which shows the FIB photograph of a 40 micrometer depth position from the surface after ion-implanting to an electroforming material. It is the figure which drawn the micro structure of the A section of FIG.

Explanation of symbols

  1 electroformed material, 2 accelerated ions, 3 substrate, 4 voids, 5 crystal grains.

Claims (14)

  An ion-implanted electroformed member, which is a member having an ion-implanted layer formed by implanting ions into an electroformed material formed by electroforming.   The ion according to claim 1, wherein an ion-implanted layer is formed in a surface layer portion having a depth range of 5 μm or less from the surface of the ion-implanted electroformed member, and a microstructure is modulated at a deeper position than the ion-implanted layer. Injection electroformed member.   The ion-implanted electroformed member according to claim 2, wherein the microstructure is modulated at a position in the center of the cross section that enters the inside from the surface.   4. The ion-implanted electroformed member according to claim 2, wherein an average crystal grain size of a portion where the microstructure is modulated is 0.5 μm or less.   The ion-implanted electroformed member according to any one of claims 2 to 4, wherein a hardness of a portion where the microstructure is modulated is harder than a hardness of an electroformed material formed by the electroforming.   The ion-implanted electroformed member according to claim 1, wherein an average particle diameter of crystal grains of the electroformed material formed by the electroforming is 1 μm or less.   A method for manufacturing an ion-implanted electroformed member, comprising: a step of forming an electroformed material; and a step of implanting accelerated ions into the electroformed material.   The method for producing an ion-implanted electroformed member according to claim 7, wherein the step of forming the electroformed material is performed such that an average crystal grain size of the electroformed material is 1 μm or less.   The method for manufacturing an ion-implanted electroformed member according to claim 7 or 8, wherein a voltage is applied in a pulse shape in the step of forming the electroformed material.   The method for manufacturing an ion-implanted electroformed member according to any one of claims 7 to 9, wherein, in the ion implantation step, ions are implanted in a range of 5 µm or less from the surface, and the internal hardness is thereby increased.   The ion-implanted electroformed member according to any one of claims 7 to 10, wherein in the ion-implanting step, ions are implanted in a range of 5 µm or less from the surface, and the inner structure is made a modulated structure. Method.   The ion implantation according to any one of claims 7 to 11, wherein, in the ion implantation step, a temperature of the electroformed material is set to (1/3) or less of a melting point (K) of a material constituting the electroformed material. A method for producing an electroformed member.   The method for manufacturing an ion-implanted electroformed member according to any one of claims 7 to 12, wherein in the ion implantation, ions are accelerated at a voltage of 10 kV or more.   The method for manufacturing an ion-implanted electroformed member according to claim 7, wherein an omnidirectional plasma ion implantation apparatus is used in the ion implantation.