JP2008176892A - Manufacturing method of uneveness reverse plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately manufacture an uneveness reverse plate having a minute uneven shape. <P>SOLUTION: A manufacturing method of the uneveness reverse plate using an original plate containing Si includes a thin film forming step for forming a metal thin film 61 having 5 to 60 nm film thickness as a conductive layer on a surface of the original plate where an uneven shape is formed, a plating process for forming a metal plate 63 including the conductive layer by performing electroplating on the metal thin film 61 and a peeling process for peeling the metal plate 63 from the original plate 63. The original plate is e.g. a stamper original plate 50 for an optical information recording medium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a concavo-convex inverted plate such as a stamper for optical information recording media and a master for magnetic transfer.

  2. Description of the Related Art In recent years, with the demand for higher density optical information recording media, high-density optical information recording media that perform recording and / or reproduction using laser light of 450 nm or less have been developed. This high-density optical information recording medium is manufactured by applying a dye on a resin substrate on which grooves used for laser beam tracking are formed, and further attaching a substrate for protecting the dye recording layer. The resin substrate at this time can be manufactured by using, as one of the molds, a metal stamper having a surface shape obtained by inverting the groove pattern when performing resin injection molding.

  Further, this stamper is duplicated based on the uneven pattern of the stamper original. For example, as disclosed in Patent Document 1, a stamper master is manufactured by forming a photoresist layer on a glass substrate, exposing a pit or uneven shape with a laser beam, and developing by etching. Then, a conductive layer is formed on the stamper original plate with nickel or the like, nickel is electroplated on the conductive layer to form a nickel thick film, and the nickel thick film is peeled off from the stamper original plate, whereby the stamper is manufactured. .

JP 2001-126321 A

  By the way, according to research by the inventors, when electroplating is performed by forming a conductive layer on a stamper master having a fine concavo-convex shape, the electroplating becomes defective even if the conductive layer is too thick or too thin. It turned out to be possible.

  It has also been found that when the amount of impurities in the conductive layer is large or there are many defects in the conductive layer, the electroplating is not good and a dent-like defect is formed.

  This invention is made | formed in view of the above backgrounds, and makes it a subject to provide the method of manufacturing suitably the stamper for optical information media which has a fine uneven | corrugated shape.

  The present invention for solving the above-described problems is a method for producing a concavo-convex inversion plate using an original plate containing Si and having a concavo-convex shape formed on the surface of the original plate on which the concavo-convex shape is formed. A thin film forming step of forming a conductive layer with a thickness of ˜60 nm, a plating step of forming a metal plate including the conductive layer by electroplating on the conductive layer, and peeling the metal plate from the original plate And a peeling step.

  In addition, the present invention for solving the above-described problems is a method for producing a concavo-convex inversion plate using an original plate containing Si and having a concavo-convex recess having a pattern line width of 150 nm or less. A thin film forming step of forming a conductive layer with a film thickness of 5 to 50% of the pattern line width on the surface of the original plate on which the concavo-convex shape is formed, and electroplating on the conductive layer, It has the plating process which forms the metal plate containing a layer, and the peeling process which peels the said metal plate from the said original plate, It is characterized by the above-mentioned.

  In this manufacturing method, it is desirable to form the conductive layer with a film thickness of 5 to 25% of the pattern line width.

By forming the conductive layer with the thickness as described above, the current flowing through the conductive layer is stabilized in the plating step, and a good metal plate can be formed.
In addition, the thickness of the conductive layer as used in this specification means the film thickness in a convex part among the uneven | corrugated shapes of an original.
But it is preferable that it is the film thickness prescribed | regulated to this specification in all the site | parts of a convex part, a side part, and a recessed part among uneven | corrugated shapes.

  Further, the present invention for solving the above-mentioned problems is a method for producing a concavo-convex inversion plate using an original plate containing Si and having a concavo-convex shape, wherein the concavo-convex shape of the original plate is formed. A thin film forming step of forming a conductive layer with a conductive layer material, a plating step of forming a metal plate including the conductive layer by electroplating on the conductive layer, and peeling the metal plate from the original plate A peeling step, wherein the thin film forming step has a ratio of the conductive layer material in the conductive layer of 95 wt% or more, and the conductive layer of a substance that becomes an anion in the plating solution used in the plating step The conductive layer is formed so that the ratio thereof is 5 wt% or less.

  Thus, since there are few impurities, such as F, Cl, and O, the electric current which flows into a conductive layer is stabilized and it is possible to form a favorable metal plate.

Further, the present invention for solving the above-mentioned problems is a method for producing a concavo-convex reversal plate using an original plate having a concavo-convex shape, wherein the conductive layer material is formed on the surface of the original plate having the concavo-convex shape formed thereon. A thin film forming step for forming a metal plate, a plating step for forming a metal plate including the conductive layer by electroplating on the conductive layer, and a peeling step for peeling the metal plate from the original plate. In the thin film forming step, the volume resistivity of the conductive layer is 1.2 × 10 ⁻⁴ Ω · cm or less.

By forming the conductive layer under such conditions, that is, the volume resistivity is 1.2 × 10 ⁻⁴ Ω · cm or less, the current flowing through the conductive layer is stabilized, and a good metal plate can be formed. .
In this case, if Ni is used as the conductive layer material, the density of the conductive layer is preferably 7.7 g / cm ³ or more. By forming the conductive layer densely to this extent, the current flow in the conductive layer can be stabilized.

Each manufacturing method described above may have a punching step of punching the metal plate peeled in the peeling step into a predetermined shape.
A stamper for optical information recording medium, a master for magnetic transfer, or a master for nanoimprinting can be selected as a concavo-convex inverted plate to be manufactured. Since these are required to form a fine and highly accurate concavo-convex shape, the present invention can be suitably applied.

  Here, the stamper for an optical information recording medium manufactured by the manufacturing method of the present invention is used for manufacturing a dye-based optical information recording medium with a short wavelength laser beam. For example, in the currently proposed Blu-ray Disc specification, a management information recording area (for example, a BCA (Burst Cutting Area) area) in which information such as disc information is recorded is formed on the inner periphery of the optical information recording medium. . The BCA area is an area corresponding to an area where a BCA signal is recorded. FIG. 1 is a plan view of a stamper master for producing this optical information recording medium, and hatching indicates a region. As shown in FIG. 1, the disk-shaped stamper master 50 has a data storage area A1 in which a first pregroove is formed in a spiral shape (not shown) in a donut-shaped area. A BCA area A2 is formed on the inner peripheral side of the data storage area A1. A spiral (not shown) second pregroove is also formed in the BCA region.

  In an optical information recording medium manufactured using the stamper master 50 (specifically, manufactured using a stamper manufactured from the stamper master 50), a BCA signal is transmitted to the dye recording layer and / or the reflective layer by a laser. It is formed into a barcode by light. A pre-groove (second pre-groove) needs to be formed in the BCA area, but the groove depth is preferably formed shallower than the pre-groove (first pre-groove) in the data recording area.

  According to the present invention, it is possible to manufacture a concavo-convex inverted plate having a fine concavo-convex shape by accurately inverting the original plate.

  Next, an embodiment relating to a method for manufacturing a stamper for optical information recording media (hereinafter simply referred to as “stamper”), which is an example of the concavo-convex inverted plate of the present invention, will be described in detail with reference to the drawings as appropriate.

First, an example of an optical information recording medium manufactured by a stamper obtained by the manufacturing method of the present invention will be described.
In the drawings to be referred to, FIG. 2 is a diagram for explaining a groove depth, and FIG. 3 is a cross-sectional view showing a layer structure of an optical information recording medium using a stamper original plate or a stamper manufactured by the manufacturing method of the present invention. FIG.

  As shown in FIG. 3, the optical information recording medium 10 includes a write-once recording layer 14 containing a dye and a cover layer having a thickness of 0.01 to 0.5 mm on a substrate 12 having a thickness of 0.7 to 2 mm. 16 in this order. Specifically, for example, the light reflection layer 18, the write-once recording layer 14, the barrier layer 20, the adhesive layer 22, and the cover layer 16 are provided on the substrate 12 in this order.

[Substrate 12]
As shown in FIG. 3, the substrate 12 of the preferred optical information recording medium 10 has a first pregroove 34 (guide groove) having a shape in which the track pitch, groove width, groove depth, and wobble amplitude are in the following ranges. A second pregroove 35 is formed.
As shown in FIG. 2, the groove depth is measured by a width W (half-value width) at a half depth position when the depth is H.
The first pregroove 34 is provided in order to achieve a higher recording density than CD-R and DVD-R. For example, the optical information recording medium 10 is used as a medium corresponding to a blue-violet laser. It is suitable for use.
The second pregroove 35 has a slightly smaller groove width and groove depth than the first pregroove 34, and is provided on the inner circumference side of the optical information recording medium 10 when it is disc-shaped. The second pregroove 35 is used as a BCA area in which, for example, manufacturer information of the optical information recording medium 10 and other management information are recorded. In the BCA area, the reflectivity needs to be lower than that of the data storage area in terms of signal characteristics, so that the groove width is shallower than that of the data storage area.

  The track pitch of the first pregroove 34 is, for example, about 320 nm, and can be appropriately changed according to the specifications of the optical information recording medium.

The groove width (half width) of the first pregroove 34 is desirably in the range of 90 to 180 nm.
If the groove width of the first pregroove 34 is less than 90 nm, the groove may not be sufficiently transferred during molding or the recording error rate may increase. If it exceeds 180 nm, the pits formed during recording spread. As a result, crosstalk may occur or a sufficient degree of modulation may not be obtained.

  The groove depth a of the first pregroove 34 is 60 nm or less, preferably 30 to 50 nm, more preferably 35 to 45 nm. If the groove depth of the first pre-groove 34 is less than 5 nm, a sufficient recording modulation degree may not be obtained, and if it exceeds 60 nm, the reflectance may be significantly lowered.

Further, the upper limit of the groove inclination angle of the first pregroove 34 is preferably 80 ° or less, more preferably 70 ° or less, further preferably 60 ° or less, and 50 ° or less. It is particularly preferred. Further, the lower limit value is preferably 20 ° or more, more preferably 30 ° or more, and further preferably 40 ° or more.
If the groove inclination angle of the first pregroove 34 is less than 20 °, a sufficient tracking error signal amplitude may not be obtained. If it exceeds 80 °, it is difficult to mold the substrate 12 (such as injection molding).

  The groove depth b of the second pregroove 35 is in the range of 5 to 30 nm, and more preferably in the range of 8 to 17 nm.

  The groove width (half-value width) of the second pregroove 35 is appropriately set within a range in which the groove depth can be obtained.

  A preferable groove inclination angle of the second pregroove 35 is the same as that of the first pregroove 34.

  As the substrate 12 used in the optical information recording medium 10, various materials used as substrate materials for conventional optical information recording media can be arbitrarily selected and used.

Among the substrate materials, thermoplastic resins such as amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable from the viewpoints of moisture resistance, dimensional stability, and low cost.
When these resins are used, the substrate 12 can be manufactured by injection molding.

Moreover, the thickness of the board | substrate 12 is the range of 0.7-2 mm, it is preferable that it is the range of 0.9-1.6 mm, and it is more preferable to set it as 1.0-1.3 mm.
In addition, it is preferable to form an undercoat layer on the surface of the substrate 12 on the side where the light reflecting layer 18 described later is provided for the purpose of improving the flatness and the adhesive force.

[Write-once recording layer 14]
The write-once recording layer 14 of the preferred optical information recording medium 10 is prepared by dissolving a dye in a suitable solvent together with a binder or the like to prepare a coating solution, and then applying this coating solution on a substrate or a light reflecting layer 18 described later. It is formed by applying a coating film on the top and then drying. Here, the write-once recording layer 14 may be a single layer or a multilayer. In the case of a multilayer structure, the step of applying the coating liquid is performed a plurality of times.
Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method.

  The thickness of the write-once recording layer 14 formed in this manner is preferably 300 nm or less, more preferably 250 nm or less, and more preferably 200 nm or less on the groove 38 (convex portion in the substrate 12). More preferably, it is particularly preferably 180 nm or less. The lower limit is preferably 30 nm or more, more preferably 50 nm or more, further preferably 70 nm or more, and particularly preferably 90 nm or more.

  Further, the thickness of the write-once recording layer 14 is preferably 400 nm or less, more preferably 300 nm or less, and further preferably 250 nm or less on the land 40 (a concave portion in the substrate 12). The lower limit is preferably 70 nm or more, more preferably 90 nm or more, and further preferably 110 nm or more.

  Further, the ratio (t1 / t2) between the thickness t1 of the write-once recording layer 14 on the groove 38 and the thickness t2 of the write-once recording layer 14 on the land 40 is preferably 0.4 or more, It is more preferably 0.5 or more, further preferably 0.6 or more, and particularly preferably 0.7 or more. The upper limit value is preferably less than 1, more preferably 0.9 or less, further preferably 0.85 or less, and particularly preferably 0.8 or less.

[Cover layer 16]
The cover layer 16 of the preferred optical information recording medium 10 is bonded to the write-once recording layer 14 described above or a barrier layer 20 described later via an adhesive layer 22 made of an adhesive, an adhesive, or the like.

The cover layer 16 used in the optical information recording medium 10 is not particularly limited as long as it is a transparent film, but is not limited to acrylic resins such as polycarbonate and polymethyl methacrylate; chlorides such as polyvinyl chloride and vinyl chloride copolymers. It is preferable to use vinyl resin; epoxy resin; amorphous polyolefin; polyester; cellulose triacetate. Among them, it is more preferable to use polycarbonate or cellulose triacetate.
Note that “transparent” means that the transmittance is 80% or more with respect to light used for recording and reproduction.

  The cover layer 16 may contain various additives as long as the effects of the present invention are not hindered. For example, a UV absorber for cutting light having a wavelength of 400 nm or less and / or a dye for cutting light having a wavelength of 500 nm or more may be contained.

Further, as the surface physical properties of the cover layer 16, it is preferable that both the two-dimensional roughness parameter and the three-dimensional roughness parameter have a surface roughness of 5 nm or less.
Further, from the viewpoint of the concentration of light used for recording and reproduction, the birefringence of the cover layer 16 is preferably 10 nm or less.

  The thickness of the cover layer 16 is appropriately determined by the wavelength of the laser beam 46 irradiated for recording and reproduction and the NA of the objective lens 45. In the optical information recording medium 10, the thickness of the cover layer 16 is 0.01-0. Within the range of 0.5 mm, more preferably within the range of 0.05 to 0.12 mm.

  Further, the total thickness of the cover layer 16 and the adhesive layer 22 is preferably 0.09 to 0.11 mm, and more preferably 0.095 to 0.105 mm.

  The light incident surface of the cover layer 16 may be provided with a hard coat layer 44 (protective layer) for preventing the light incident surface from being damaged when the optical information recording medium 10 is manufactured.

  As the adhesive used for the adhesive layer 22, for example, a UV curable resin, an EB curable resin, a thermosetting resin or the like is preferably used, and in particular, a UV curable resin is preferably used.

  When using a UV curable resin as an adhesive, prepare the coating solution by dissolving the UV curable resin as it is or in an appropriate solvent such as methyl ethyl ketone or ethyl acetate, and supply it to the surface of the barrier layer 20 from the dispenser. Also good. Further, in order to prevent warping of the optical information recording medium 10 to be produced, it is preferable that the UV curable resin constituting the adhesive layer 22 has a small curing shrinkage rate. Examples of such UV curable resins include UV curable resins such as “SD-640” manufactured by Dainippon Ink and Chemicals, Inc.

  For example, a predetermined amount of the adhesive is applied onto the bonding surface including the barrier layer 20, and the cover layer 16 is placed thereon. Then, the adhesive is applied by spin coating to the bonding surface and the cover layer. It is preferable to cure the film after it has been uniformly spread between the two.

  The thickness of the adhesive layer 22 made of such an adhesive is preferably in the range of 0.1 to 100 μm, more preferably in the range of 0.5 to 50 μm, and still more preferably in the range of 10 to 30 μm.

  As the pressure-sensitive adhesive used for the adhesive layer 22, acrylic, rubber-based, and silicon-based pressure-sensitive adhesives can be used. From the viewpoints of transparency and durability, acrylic-based pressure-sensitive adhesives are preferable.

The pressure-sensitive adhesive may be uniformly applied in a predetermined amount on the surface to be bonded comprising the barrier layer 20, and the cover layer 16 may be placed thereon and then cured. A predetermined amount may be uniformly applied to one surface to form a pressure-sensitive adhesive coating, and the coating may be bonded to the surface to be bonded, and then cured.
Moreover, you may use the commercially available adhesive film in which the adhesive layer was previously provided for the cover layer 16. FIG.
The thickness of the adhesive layer 22 made of such a pressure-sensitive adhesive is preferably in the range of 0.1 to 100 μm, more preferably in the range of 0.5 to 50 μm, and still more preferably in the range of 10 to 30 μm.

[Other layers in the optical information recording medium 10]
The preferred optical information recording medium 10 may have other arbitrary layers in addition to the above-described layers. Examples of such other optional layers include a label layer having a desired image formed on the back surface of the substrate 12 (the back surface with respect to the formation surface of the write-once recording layer 14), the substrate 12 and the write-once recording layer 14, and the like. A light reflecting layer 18 (described later) provided between the barrier layer 20 (described later) provided between the write-once recording layer 14 and the cover layer 16, and provided between the light reflecting layer 18 and the write-once recording layer 14. And an interface layer. Here, the label layer is formed using an ultraviolet curable resin, a thermosetting resin, a heat drying resin, or the like.
Note that each of the above layers may be a single layer or may have a multilayer structure.

[Light reflecting layer 18]
In the optical information recording medium 10, a light reflecting layer 18 is formed between the substrate 12 and the write-once recording layer 14 in order to increase the reflectivity with respect to the laser light 46 and to give the function of improving the recording / reproducing characteristics. It is preferable.

The light reflecting layer 18 can be formed on the substrate 12 by vacuum deposition, sputtering or ion plating of a light reflecting material having a high reflectance with respect to the laser light 46.
The layer thickness of the light reflecting layer 18 is generally in the range of 10 to 300 nm and preferably in the range of 50 to 200 nm.
The reflectance is preferably 70% or more.

  As the material of the reflective layer, Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt , Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, and other metals and semi-metals or stainless steel.

[Barrier layer 20 (intermediate layer)]
In the optical information recording medium 10, it is preferable to form a barrier layer 20 between the write-once recording layer 14 and the cover layer 16.
The barrier layer 20 is used for improving the storability of the write-once recording layer 14, improving the adhesion between the write-once recording layer 14 and the cover layer 16, adjusting the reflectance, adjusting the thermal conductivity, etc. Provided.

The material used for the barrier layer 20 is not particularly limited as long as it is a material that transmits light used for recording and reproduction and can express the above functions. Is a material with low permeability of gas and moisture, and is preferably a dielectric.
The barrier layer 20 can be formed by a vacuum film formation method such as vacuum deposition, DC sputtering, RF sputtering, or ion plating. Among these, it is more preferable to use sputtering, and it is more preferable to use RF sputtering.
The thickness of the barrier layer 20 is preferably in the range of 1 to 200 nm, more preferably in the range of 2 to 100 nm, and still more preferably in the range of 3 to 50 nm.

<Optical information recording method>
In the optical information recording medium 10, first, while rotating the optical information recording medium 10 at a constant linear velocity (0.5 to 10 m / second) or a constant angular velocity, the optical information recording medium 10 is used for recording semiconductor laser light or the like from the cover layer 16 side. Laser light 46 is irradiated through an objective lens 45 having a numerical aperture NA of, for example, 0.85. By the irradiation of the laser beam 46, the write-once recording layer 14 absorbs the laser beam 46 and the temperature rises locally, causing a physical or chemical change (for example, generation of pits) to change its optical characteristics. Thus, it is considered that information is recorded.

  As the recording laser beam 46, a semiconductor laser beam having an oscillation wavelength in the range of 390 to 450 nm is used. As a preferable light source, a blue-violet semiconductor laser beam having an oscillation wavelength in the range of 390 to 415 nm and an infrared semiconductor laser beam having a center oscillation wavelength of 850 nm are made a half wavelength using an optical waveguide device, and a blue-violet color having a center oscillation wavelength of 425 nm is used. SHG laser light can be mentioned. In particular, it is preferable to use a blue-violet semiconductor laser beam having an oscillation wavelength in the range of 390 to 415 nm in terms of recording density. Reproduction of information recorded as described above is performed by irradiating a semiconductor laser beam from the substrate side or the protective layer side while rotating the optical information recording medium 10 at the same constant linear velocity as described above, and detecting the reflected light. Can be done.

  As the laser light 46, a near-infrared laser light (usually a laser light having a wavelength near 780 nm), a visible laser light (630 nm to 680 nm), a laser light having a wavelength of 530 nm or less (a 405 nm blue laser), or the like is used. It is also possible to use visible laser light (630 nm to 680 nm) and laser light having a wavelength of 530 nm or less (405 nm blue laser), and in particular, laser light having a wavelength of 530 nm or less (405 nm blue laser). Preferably there is.

  Next, a stamper for manufacturing the substrate 12 of the optical information recording medium 10 as described above and a method for manufacturing a stamper original plate for manufacturing the stamper will be described.

[Method of manufacturing stamper master]
The stamper master is a mold for manufacturing a stamper, and is manufactured as follows.
In the drawings to be referred to, FIG. 4 is a diagram showing a manufacturing process of the stamper original plate.

(Resist layer formation process)
First, a silicon wafer 51 (for example, an 8-inch dummy wafer manufactured by Fujimi Fine Technology) as a silicon-containing substrate having a smooth surface is prepared. Next, a pretreatment for forming an adhesion layer on the silicon wafer 51 is performed. Then, as shown in FIG. 4A, an electron beam resist solution is applied by a method such as spin coating to form a resist layer 52 and baked. For the electron beam resist solution, FEP-171 manufactured by Fuji Film Electromaterials Co., Ltd. is used, and the film thickness can be 100 nm.

(Electron beam irradiation process)
Next, as shown in FIG. 4B, the resist layer 52 is irradiated with an electron beam modulated in accordance with various signals such as an address by an electron beam exposure apparatus having a high-precision rotary stage, and a desired pattern is formed on the resist layer 52. Draw by exposure. At this time, if the pattern to be drawn is drawn with the first exposure line 531 corresponding to the first pre-groove 34 and the second exposure line 532 corresponding to the second pre-groove 35 and thinner than the first exposure line 531. Good.

The line width by electron beam exposure is 100 to 180 nm, and more preferably 120 to 140 nm. For example, the first exposure line 531 (data area) may be drawn at 140 nm, and the second exposure line (BCA area) 532 may be drawn at 100 nm. The address recorded in the first pregroove 34 or the second pregroove 35 can be recorded by modulating the first exposure line 531 or the second exposure line 532 in a wave shape. The wave amplitude (wobble width) at this time can be 14 to 24 nm, more preferably 15 to 17 nm.
As an electron beam for drawing the first exposure line 531 and the second exposure line 532, one having an acceleration voltage of 50 kV can be used.
The first exposure line 531 and the second exposure line 532 may be lines in which dots are arranged.

(Development process)
Thereafter, as shown in FIG. 4C, the resist layer 52 is developed with a developer, and the exposed portions (first exposure line 531 and second exposure line 532) are removed. By this processing, openings 54 (541, 542) having a predetermined pattern are formed in the resist layer 52. Specifically, a first opening 541 is formed corresponding to the first exposure line 531 having a large width, and a second opening 542 is formed corresponding to the second exposure line 532 having a narrow width. Note that FHD-5 manufactured by FUJIFILM ELECTRO MATERIALS can be used as the developer.

(Etching process)
Next, as shown in FIG. 4D, an etching gas is made to collide with the silicon wafer 51 from the opening 54 of the resist layer 52 by etching, so that the silicon wafer 51 has a desired depth, for example, 30 to 50 nm, most preferably. Remove about 40 nm. In this etching, anisotropic etching is desirable in order to minimize undercutting, that is, etching in a direction perpendicular to the depth direction. As such anisotropic etching, RIE (Reactive Ion Etching) in which the etching gas has high straightness can be used.
By the etching process, a wide first groove 551 corresponding to the first opening 541 and a narrow second groove 552 corresponding to the second opening 542 are formed in the silicon wafer 51. The depths of the first groove 551 and the second groove 552 are also different depending on the size of the opening 54, and the depth a of the first groove 551 is 60 nm or less, which is deeper than the second groove 552, preferably 30 to About 50 nm, More preferably, it is 35-45 nm. The depth b of the second groove 552 is shallow and is about 5 to 30 nm, preferably 8 to 17 nm. That is, it is formed in a relationship of a> b.
The angles of the side walls of the first groove 551 and the second groove 552 are preferably in the range of 40 to 80 degrees with respect to the surface of the silicon wafer 51, and more preferably in the range of 55 to 65 degrees.
For RIE, E620 manufactured by Panasonic Factory Solutions can be used. Further, CHF ₃ can be used as an etching gas.
Further, the angle of the side wall can be controlled by a reaction product of Si and etching gas. For example, the test is performed by changing the state of the reaction product by changing the gas flow rate, pressure, or the like by using gases with different generation amounts of the reaction product, and setting the side wall of the formed groove to a desired angle.

(Resist removal process)
Next, the resist layer 52 remaining in the etching process is removed. For example, as a dry method, the resist layer 52 can be removed by irradiating oxygen plasma to remove organic substances (ashing). Note that the resist layer 52 may be removed by a wet method such as a stripping solution.
As shown in FIG. 4E, the stamper master 50 is manufactured by the above steps.
In this way, the stamper original plate 50 is formed with two types of grooves (first groove 551 and second groove 552) that are extremely fine but have different sizes with high accuracy.

[Method of manufacturing stamper]
Next, as an embodiment of the present invention, electroforming for producing a stamper from the stamper master 50 will be described.
FIG. 5 is a diagram showing a stamper manufacturing process.

(Thin film formation process)
In order to manufacture the stamper 60 (see FIG. 5E) from the stamper master 50, a metal plate having a shape in which the surface of the stamper master 50 is inverted by electroforming using the stamper master 50 is made.
First, as shown in FIG. 5A, as a pretreatment for performing electroplating on the stamper original plate 50, that is, a treatment for forming a conductive layer, a metal having a thickness of several tens of nm, for example, about 18 nm is formed by a method such as sputtering. A thin film 61 is formed. Thereby, conductivity is imparted to the surface of the silicon wafer 51. As a material (conductive layer material) of the metal thin film 61, for example, any of Ni, Fe, Co, alloys thereof, and FeCo alloys can be used.

The metal thin film 61 as the conductive layer is preferably formed with a film thickness of 5 to 60 nm. Further, when the pattern line width of the recesses in the concavo-convex shape of the stamper original plate 50 is 150 nm or less, the film thickness of the metal thin film 61 is preferably 5 to 50% of the pattern line width. More preferably, the film thickness is 5 to 25%.
When the thickness of the metal thin film 61 is too thin, for example, when it is 5 nm or less, or when it is 5% or less of the pattern line width of the recess, it is not possible to secure a conduction path through which a stable current flows in the metal thin film 61. In some cases, the electroplated layer 62 cannot grow from a position where conduction is not sufficient. When the metal thin film 61 is formed thick, as shown in FIG. 6A, the metal thin film 61 is not sufficiently formed near the bottom 551a of the first groove 551, for example. There is a tendency that the metal thin film 61 is thickly formed on the top portion 555a and the corner portion 555b of the land 555 between the first grooves 551. Thus, if there is a large difference in the film thickness of the metal thin film 61 between the first groove 551 and the land 555, the current flowing in the metal thin film 61 is not stable and uniform electroplating cannot be performed. This may cause generation or poor growth of the electroplated layer 62. Therefore, as shown in FIG. 6B, it is preferable that the metal thin film 61 is formed with a substantially uniform film thickness in both the first groove 551 and the land 555. It is good to do.

Moreover, it is desirable that the metal thin film 61 as the conductive layer has as few defects as possible and has a high density. For example, it is desirable that the volume resistivity of the metal thin film 61 is 1.2 × 10 ⁻⁴ Ω · cm or less. When the volume resistivity of the metal thin film 61 is larger than 1.2 × 10 ⁻⁴ Ω · cm, there are many defects in the metal thin film 61 and the current flow becomes unstable, so that the electroplated layer 62 can grow. In some cases, the formed metal plate 63 may have a dent-like defect (as viewed from a surface having a concavo-convex shape serving as a stamper). When forming the metal thin film 61 with Ni as a main component, the density of the metal thin film 61 is preferably set to 7.7 g / cm ³ or more. This is because the same problem occurs when the density of the metal thin film 61 containing Ni as a main component is smaller than 7.7 g / cm ³ .
In addition, the measuring method of the density of the metal thin film 61 is based on the X-ray reflectivity method, and the measuring method of the volume resistivity is based on the four probe method. As a reference value, dense Ni metal has a density of 8.91 g / cm ³ and a volume resistivity of 7.2 × 10 ⁻⁶ Ω · cm.

Furthermore, it is desirable that the metal thin film 61 as the conductive layer has an impurity ratio of a certain value or less. When the metal thin film 61 is formed with Ni as a main component, the ratio of Ni in the metal thin film 61 is 95 wt% or more, and the substance that becomes an anion in the plating solution used in the next plating step is 5 wt% or less. It is good. The substance which becomes an anion in the plating solution is more preferably 1% or less, and further preferably 0.1% or less.
The fact that the concentration of these impurities is preferably in the above range is the same when a conductive layer material other than Ni is used.

  Examples of substances that become anions in the plating solution include F, Cl, and O. When these impurities are large, the formed metal plate 63 has a concave shape (as viewed from a surface having a concave / convex shape to be a stamper). ) Defects may be formed.

  It should be noted that the above-described dent-like defect is a considerably large dent compared to the uneven shape such as the first groove 551 of the stamper original plate. The cause of the formation of the dent-like defect is not clear, but it is presumed that gas is generated in the plating process. According to experiments by the inventors, when the density of the metal thin film 61 is low or when the content of F, Cl, O, etc. in the metal thin film 61 is high, it is confirmed that the number of concave defects is large. ing.

(Plating process)
Next, the stamper original plate 50 on which the metal thin film 61 is formed is placed in, for example, a plating solution (temperature 55 ° C.) mainly composed of nickel sulfamate, and the metal is 295 ± 5 μm as shown in FIG. The electroplating layer 62 is formed by electroplating to a certain thickness. The same material as the metal thin film 61 can be used for the electroplating layer 62.
Note that when conducting electroplating, in order to conduct electricity to the metal thin film 61, a conductive ring having a size surrounding the uneven shape of the stamper master 50 is brought into contact with the metal thin film 61. When such a conductive ring is used, the electric lines of force in the plating solution are concentrated near the conductive ring, and the nickel electroplated layer 62 grows from the vicinity of the conductive ring.

(Peeling process)
Next, as shown in FIG. 5C, the metal plate 63 composed of the metal thin film 61 and the electroplating layer 62 is peeled off from the stamper original plate 50. At the time of peeling, the stamper original plate 50 is immersed in a liquid that is substantially the same temperature as the plating solution used in the plating process, for example, within ± 5 ° C. with respect to the temperature of the plating solution, and the metal plate 63 is washed away while washing the plating solution. It is advisable to inject pure hot water between the stamper master 50 and the stamper master 50. As the liquid at this time, pure water (pure warm water) can be used.

(Punching process)
It is preferable to provide a protective film on the surface of the metal plate 63 prepared by peeling as described above (the surface on which the uneven shape is formed). To form such a protective film, a protective agent such as Shirotite II manufactured by Hirotec Co., Ltd. is applied and dried to form a protective film 64 on the surface as shown in FIG.

  The metal plate 63 coated with the protective film 64 is punched with a press machine having an outer diameter of 138 mm and an inner diameter of 22 mm, and the inner and outer diameters are machined.

Then, the back surface of the metal plate 63 is polished and smoothed by a rotary polishing apparatus. As for the surface roughness at this time, Ra should be 1.5 μm or less, preferably 0.1 μm or less.
Next, as shown in FIG. 5E, the protective film 64 is peeled off, and the remnants of the protective film 64 are peeled off by ashing or the like by irradiation with oxygen plasma, whereby the stamper 60 is completed.
In the above method, the order of the punching and subsequent inner and outer diameter machining steps and the back surface smoothing step can be reversed.

(Inspection process)
After the stamper 60 is completed, a cover layer similar to the cover layer 16 of the optical information recording medium 10 is attached to the surface to protect the surface, and then the groove quality of the stamper 60 is confirmed by an electrical signal inspection device.
As the electrical signal inspection apparatus, a conventionally known apparatus can be used. As inspection contents, groove reflectivity and its fluctuation, push-pull signal (wobble shape) confirmation, and address error rate by a signal detector. It is recommended to perform measurement and inspection of foreign matter with a dust inspection machine.

In this way, the stamper 60 to which the uneven shape on the surface of the stamper master 50 is transferred is formed.
According to the manufacturing method of the stamper 60 as described above, since the metal thin film 61 as the conductive layer is formed with an appropriate film thickness, a current flows stably in the metal thin film 61 in the plating process, and a good metal plate 63 is obtained. Can be formed.

Further, by setting the ratio of impurities other than Ni in the metal thin film 61, in particular, a substance that becomes anions in the plating solution used in the plating process, to 5% or less, the current flow in the metal thin film 61 is stabilized and the dents are formed. It is possible to form a good metal plate 63 without forming a shape defect.
Furthermore, by forming the metal thin film 61 with a volume resistivity of 1.2 × 10 ⁻⁴ Ω · cm or less, the current flowing through the metal thin film 61 is stabilized, and a good metal plate 63 without a dent-like defect is formed. Can be formed. Further, when the metal thin film 61 is formed of Ni, the current flowing through the metal thin film 61 can be stabilized and the good metal plate 63 can be formed even if the density of the metal thin film 61 is 7.7 g / cm ³ or more. it can.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and implemented without departing from the gist of the present invention.
For example, in the above-described embodiment, the metal thin film 61 and the electroplating layer 62 are made of the same material (nickel). However, the electroplating layer 62 may be a metal thin film as long as the adhesion to the metal thin film 61 is good. A material different from the material of 61 may be used.
In the above embodiment, the optical information recording medium stamper is exemplified as the concavo-convex inversion plate. However, the magnetic transfer master for recording the servo signal on the magnetic recording medium by magnetic transfer, or the fine concavo-convex etched in the mold is used. The manufacturing method of the present invention can also be suitably applied to a nanoimprint master for transferring a shape by pressing against a material.

[Example 1]
Next, examples in which the effects of the present invention have been confirmed will be described.
Similar to the above-described embodiment, a conductive layer was formed on a stamper original plate made of a Si-containing substrate having a fine concavo-convex shape on the surface. The material of this conductive layer was Ni.
Further, spiral fine grooves were formed on the stamper original plate, and the size of the grooves was 110 nm in width and 45 nm in depth.
Sputtering was used to form the Ni conductive layer. The sputtering conditions are as follows.
Ar pressure 0.2Pa
Sputtering power 700W

Then, as shown in Table 1, the thickness of the conductive layer to be formed was changed to 7 types of film thicknesses from 3 nm to 100 nm to prepare a plurality of samples.
After forming the conductive layer, an attempt was made to form an electroplated layer by electroplating.
The composition of the plating solution for electroplating was 600 g / L nickel sulfamate, 40 g / L boric acid, 0.15 g / L lauryl sulfate Na as a surfactant, and the temperature of the plating solution during electroplating was 55 ° C.

The stampability shown in Table 1 indicates that x indicates that the electroplating layer could not be formed, ○ means that the stamper was formed well, and Δ indicates that a good stamper can be obtained. It means that the yield of what can be done is lower than ○.
As shown in Table 1, it was confirmed that the stamper could be formed when the thickness of the conductive layer was 5 nm to 60 nm, but the stamper could not be formed when the thickness of the conductive layer was 3 nm and 100 nm.
In this embodiment, since the groove width on the stamper is 110 nm, 60 nm corresponds to about 50% of the groove width, and 5 nm corresponds to about 5%. Therefore, it was confirmed that the stamper can be molded when the thickness of the conductive layer is in the range of about 5 to 50% of the groove width.

[Example 2]
In the same manner as in Example 1, a Ni conductive layer was formed on a stamper original plate, and as shown in Table 2, the density of the formed Ni conductive layer was changed to five types to prepare a plurality of samples.
The thickness of the Ni conductive layer at this time was 18 nm.
In order to change the density of the conductive layer, the Ar pressure during sputtering and the sputtering power were changed. The lower the sputtering power, the lower the density of the conductive layer, and the higher the sputtering power, the higher the density of the conductive layer. Therefore, the density of the conductive layer was adjusted by appropriately changing the sputtering power between 100 and 1500 W. Moreover, since the density of the conductive layer was lowered by increasing the Ar pressure, the Ar pressure was also adjusted.
After forming the conductive layer, an attempt was made to form an electroplated layer by electroplating.
The composition of the electroplating solution is the same as in Example 1.

As shown in Table 2, when the density of the conductive layer was 6.0 g / cm ³ , the electroplating layer could not be formed and the stamper could not be formed, but the density of the conductive layer was 7.7 g / cm ^3. In the above cases, it was confirmed that the stamper can be molded, and that the stamper can be molded satisfactorily at 8.0 g / cm ³ or more.

[Example 3]
In the same manner as in Example 1, a Ni conductive layer was formed on a stamper original plate, and as shown in Table 3, a plurality of samples were prepared by changing the volume resistivity of Ni to be formed into five types.
The thickness of the Ni conductive layer at this time was 18 nm.
Since the volume resistivity has a correlation with the density, the volume resistivity was adjusted by adjusting the sputtering power and the Ar pressure in the same manner as in Example 2.
After forming the conductive layer, an attempt was made to form an electroplated layer by electroplating.
The composition of the electroplating solution is the same as in Example 1.

As shown in Table 3, when the volume resistivity of the conductive layer was 3.6 × 10 ⁻⁴ Ω · cm, the electroplating layer could not be formed and the stamper could not be formed. It was confirmed that when the rate is 1.2 × 10 ⁻⁴ Ω · cm or less, the stamper can be molded, and when the rate is 7.0 × 10 ⁻⁵ Ω · cm or less, the stamper can be molded well.

It is a top view of the stamper original plate for manufacturing an optical information recording medium. It is a figure explaining groove depth. It is sectional drawing which shows the layer structure of the optical information recording medium in which the stamper original plate manufactured by the manufacturing method of this invention or a stamper is utilized. It is a figure which shows the manufacturing process of a stamper original plate. It is a figure which shows the manufacturing process of a stamper. It is sectional drawing of the stamper original plate explaining the difference by the film thickness of a conductive layer, (a) shows the case where a conductive layer is thick, (b) shows the case where a conductive layer is appropriate.

Explanation of symbols

10 optical information recording medium 50 stamper original plate 51 silicon wafer 52 resist layer 54 opening 60 stamper 61 metal thin film 62 electroplated layer 63 metal plate 64 protective film 531 first exposure line 532 second exposure line 541 first opening 542 second Opening 551 1st groove 552 2nd groove

Claims (10)

A method for producing a concavo-convex inversion plate using an original plate containing Si and having a concavo-convex shape formed thereon,
A thin film forming step of forming a conductive layer with a film thickness of 5 to 60 nm on the surface of the original plate on which the uneven shape is formed;
A plating step of forming a metal plate including the conductive layer by electroplating on the conductive layer;
A peeling step of peeling the metal plate from the original plate;
A method for producing a concavo-convex inverted plate, comprising: A method for producing a concavo-convex inverted plate using an original plate containing Si and having a concavo-convex recess having a pattern line width of 150 nm or less,
A thin film forming step of forming a conductive layer with a film thickness of 5 to 50% of the pattern line width on the surface of the original plate where the concavo-convex shape is formed;
A plating step of forming a metal plate including the conductive layer by electroplating on the conductive layer;
A peeling step of peeling the metal plate from the original plate;
A method for producing a concavo-convex inverted plate, comprising:   The method for producing a concavo-convex inverted plate according to claim 2, wherein the conductive layer is formed with a film thickness of 5 to 25% of the pattern line width. A method for producing a concavo-convex inversion plate using an original plate containing Si and having a concavo-convex shape formed thereon,
A thin film forming step of forming a conductive layer with a conductive layer material on the surface of the original plate where the irregular shape is formed;
A plating step of forming a metal plate including the conductive layer by electroplating on the conductive layer;
A peeling step of peeling the metal plate from the original plate;
Have
In the thin film forming step, a ratio of the conductive layer material in the conductive layer is 95 wt% or more, and a ratio of a substance that becomes an anion in the plating solution used in the plating step is 5 wt% or less. The method for producing a concavo-convex inversion plate, comprising forming the conductive layer as described above. A method for producing a concavo-convex inversion plate using an original plate containing Si and having a concavo-convex shape formed thereon,
A thin film forming step of forming a conductive layer with a conductive layer material on the surface of the original plate where the irregular shape is formed;
A plating step of forming a metal plate including the conductive layer by electroplating on the conductive layer;
A peeling step of peeling the metal plate from the original plate;
Have
In the thin film formation step, the volume resistivity of the conductive layer is set to 1.2 × 10 ⁻⁴ Ω · cm or less. The conductive layer material is Ni,
6. The method for producing a concavo-convex inverted plate according to claim 5, wherein the density of the conductive layer in the thin film forming step is 7.7 g / cm ³ or more.   The method for producing a concavo-convex inverted plate according to any one of claims 1 to 6, further comprising a punching step of punching the metal plate peeled in the peeling step into a predetermined shape.   The method for manufacturing a concavo-convex inverted plate according to any one of claims 1 to 7, wherein the concavo-convex inverted plate is a stamper for an optical information recording medium.   The method for producing a concavo-convex inverted plate according to any one of claims 1 to 7, wherein the concavo-convex inverted plate is a magnetic transfer master.   The method for producing a concavo-convex inverted plate according to any one of claims 1 to 7, wherein the concavo-convex inverted plate is a nanoimprint master.

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