Method for manufacturing a wiring board

Abstract

To provide a manufacturing method for a wiring board comprising an insulating substrate that can reduce a thickness of an isolation layer and a wiring layer having a prescribed wiring pattern disposed on the insulating substrate.SOLUTION: At first, (a) a patterned substrate is prepared. The patterned substrate comprises an insulating substrate, an electric conductive seed layer made of a first part having a prescribed pattern in response to the wiring pattern disposed on the insulating substrate and a second part that is the rest other than the first part and an isolation layer provided on the second part of the seed layer. Next, (b) a metallic layer with a thickness larger than the isolation layer on the first part of the seed layer is formed. A resin film containing a solution containing a metallic ion is arranged between the patterned substrate and an anode, then while pressure-welding the resin film with the seed layer, voltage is applied between the anode and the seed layer. Next, (c) the isolation layer and the second part of the seed layer are removed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a wiring board. [Background technology]

[0002] Known methods for manufacturing a wiring board include a subtractive method, a semi-additive method, and a full-additive method. In general, the semi-additive method is used for manufacturing a high-density wiring board.

[0003] Patent Document 1 discloses a method for manufacturing a wiring board using a semi-additive method. Specifically, a base layer, a dielectric layer, a seed layer, and a first plating layer are laminated in this order, a patterned resist is formed on the first plating layer by photolithography, a second plating layer is formed on the portion of the first plating layer that is exposed from the patterned resist, the patterned resist is then removed, and the first plating layer and the seed layer are removed using the second plating layer as a mask to manufacture the wiring board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-225524 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the semi-additive method using plating as described in Patent Document 1, it is necessary to form a patterned resist having a thickness equal to or greater than the thickness of the second plating layer to be formed. However, forming a thick patterned resist requires many steps. In addition, removing such a patterned resist not only requires many steps, but also generates a large amount of waste liquid.

[0006] Therefore, a method for manufacturing a wiring board that can reduce the thickness of the resist (insulating layer) is provided. [Means for solving the problem]

[0007] According to one aspect of the present invention, A method for manufacturing a wiring board including an insulating base material and a wiring layer having a predetermined wiring pattern provided on the insulating base material, comprising: (a) providing a patterned substrate, wherein the patterned substrate is The insulating substrate; a conductive seed layer provided on the insulating base material, the seed layer including a first portion having a predetermined pattern corresponding to the wiring pattern and a second portion other than the first portion; an insulating layer disposed on the second portion of the seed layer; (b) forming a metal layer on a first portion of the seed layer, the metal layer having a thickness greater than that of the insulating layer; a step of disposing a resin film containing a solution containing metal ions between the patterned substrate and an anode, and applying a voltage between the anode and the seed layer while pressing the resin film and the seed layer together; (c) removing the insulating layer and a second portion of the seed layer; A method is provided, comprising: Effect of the Invention

[0008] According to the method for manufacturing a wiring board of the present invention, the thickness of the insulating layer can be reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a flowchart showing a method for manufacturing a wiring board according to an embodiment. [Diagram 2] FIG. 2 is a flow chart showing the steps of preparing a patterned substrate in the method for manufacturing a wiring board according to the embodiment. [Diagram 3] FIG. 3 is a conceptual diagram showing the step of forming a seed layer. [Figure 4] FIG. 4 is a conceptual diagram showing the step of forming an insulating layer. [Diagram 5] FIG. 5 is a conceptual diagram showing a step of irradiating an insulating layer with a laser beam. [Figure 6] FIG. 6 is a conceptual diagram showing the steps of forming a metal layer. [Figure 7] FIG. 7 is a schematic diagram illustrating the step of removing the insulating layer and the second portion of the seed layer. [Figure 8] FIG. 8 is a schematic diagram illustrating the step of removing the insulating layer and the second portion of the seed layer. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a film forming apparatus used in the step of forming a metal layer. [Figure 10] FIG. 10 is a schematic cross-sectional view showing the film forming apparatus shown in FIG. 9 with the housing lowered to a predetermined height. [Figure 11] FIG. 11 is a flow chart showing the step of preparing a patterned substrate in the method for manufacturing a wiring board according to the first modified embodiment. [Figure 12] FIG. 12 is a conceptual diagram of a patterned substrate in a method for manufacturing a wiring board according to the third modified embodiment. [Figure 13] FIG. 13 is a cross-sectional SEM image of the wiring board of Example 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Embodiment] Hereinafter, the embodiments will be described with reference to the drawings as appropriate. In the drawings referred to in the following description, the same components or components having similar functions are given the same reference numerals, and repeated description may be omitted. In addition, the dimensional ratios in the drawings may differ from the actual ratios for convenience of explanation, and some components may be omitted from the drawings. In addition, in this application, a numerical range expressed using the symbol "~" includes the numerical values ​​written before and after the symbol "~" as the lower limit and upper limit, respectively.

[0011] The method for manufacturing a wiring board according to the embodiment includes a step (S1) of preparing a patterned substrate, a step (S2) of forming a metal layer, and a step (S3) of removing the insulating layer and a second portion of the seed layer, as shown in Fig. 1. The step (S1) of preparing a patterned substrate may include a step (S11) of forming a seed layer, a step (S12) of forming an insulating layer, and a step (S13) of irradiating the insulating layer with a laser beam (laser light), as shown in Fig. 2. Each step will be described below.

[0012] (1) Step of preparing a patterned substrate (S1) a) Formation of seed layer (S11) First, as shown in FIG. 3, a seed layer 13 is formed on an insulating base material 11.

[0013] For example, a substrate containing resin and glass, such as a glass epoxy resin substrate, a substrate made of resin, a substrate made of glass, etc., can be used as the insulating substrate 11. Examples of resins used for the insulating substrate 11 include thermoplastic resins such as PET resin, PI resin, LCP (liquid crystal polymer), epoxy resin, ABS resin, AS resin, AAS resin, PS resin, EVA resin, PMMA resin, PBT resin, PPS resin, PA resin, POM resin, PC resin, PP resin, PE resin, polymer alloy resin containing elastomer and PP, modified PPO resin, PTFE resin, and ETFE resin, thermosetting resins such as phenol resin, melamine resin, amino resin, unsaturated polyester resin, polyurethane, diallyl phthalate, silicone resin, and alkyd resin, and resins obtained by adding cyanate resin to epoxy resin, etc.

[0014] The material of the seed layer 13 is not particularly limited as long as it is conductive and allows etching of the seed layer 13 in step (S3) described later. For example, the material of the seed layer 13 may be Pt, Pd, Rh, Cu, Ag, Au, Ti, Al, Cr, Si, or an alloy thereof, FeSi2, CoSi2, MoSi2, WSi2, VSi2, ReSi 1.75, CrSi2, NbSi2, TaSi2, TiSi2, ZrSi2, etc., particularly transition metal silicides, conductive metal oxides such as TiO2, SnO, GeO, ITO (indium tin oxide), etc., or conductive resins. In order to leave a seed layer 13 having a sufficient thickness in the step (S13) of irradiating a laser beam described later, the seed layer 13 may have a thickness of 80 nm or more, preferably 100 nm or more. From the viewpoint of manufacturing costs, the seed layer 13 may have a thickness of 1000 nm or less, preferably 500 nm or less.

[0015] The seed layer 13 may be formed on the entire main surface 11a of the insulating substrate 11. The seed layer 13 may be formed by any method. For example, the seed layer 13 can be formed by a PVD (physical vapor deposition) method such as a sputtering method, a CVD (chemical vapor deposition) method, or an electroless plating method. Alternatively, the seed layer 13 can be formed by applying a dispersion liquid of conductive particles to the main surface 11a of the insulating substrate 11 and solidifying the dispersion liquid. As a dispersion medium of the dispersion liquid, a liquid that volatilizes by heating, such as decanol, can be used. The dispersion liquid may contain an additive. An example of the additive is a straight-chain fatty acid salt having 10 to 17 carbon atoms. The method of applying the dispersion liquid is not particularly limited. For example, a die coating method, a dip coating method, and a spin coating method can be used. The method of solidifying the dispersion liquid is not particularly limited. For example, the dispersion liquid can be solidified by volatilizing the dispersion medium by heating and sintering the conductive particles.

[0016] 3, the seed layer 13 is composed of a first portion R1 and a second portion R2 other than the first portion R1. The first portion R1 has a predetermined pattern corresponding to the wiring pattern of the wiring board manufactured by the manufacturing method of the embodiment.

[0017] In order to improve adhesion between the seed layer 13 and the insulating substrate 11, the main surface 11a of the insulating substrate 11 may be surface-treated before the seed layer 13 is formed. For example, a layer of a primer or the like may be formed on the main surface 11a of the insulating substrate 11. As the primer, polyimide, polyamideimide, or the like may be used. In addition, the main surface 11a of the insulating substrate 11 may be roughened. The roughening may be performed by laser irradiation, etching, desmearing, mechanical processing (polishing, grinding), or the like.

[0018] b) Formation of insulating layer (S12) 4, the insulating layer 16 is formed on the seed layer 13. That is, the insulating layer 16 is formed on the first portion R1 and the second portion R2 of the seed layer 13.

[0019] The material of the insulating layer 16 is not particularly limited as long as it is an insulating material that can be removed by irradiation with a laser beam. Examples of materials for the insulating layer 16 include thermosetting resins such as EP (epoxy) resin, resol type PF (phenol) resin, UF (urea) resin, MF (melamine) resin, UP (unsaturated polyester) resin, PUR (polyurethane) resin, DAP (diallyl phthalate) resin, SI (silicone) resin, ALK (alkyd) resin, thermosetting PI (polyimide) resin, PPO (polyphenylene oxide) resin, LCP (liquid crystal polymer), and PTFE (polytetrafluoroethylene) resin, and thermoplastic resins such as PE (polyethylene) resin, PP (polypropylene) resin, PS (polystyrene) resin, PET (polyethylene terephthalate) resin, AS (acrylonitrile-styrene copolymer) resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, PVC (polyvinyl chloride) resin, PVDC (polyvinylidene chloride) resin, acrylic resin (e.g., PMMA (polymethyl methacrylate) resin), and novolac type PF resin.

[0020] The insulating layer 16 can be formed by any method such as a die coating method, a dip coating method, a spin coating method, etc. The insulating layer 16 can also be formed by overlaying an insulating film such as a dry film resist on the seed layer 13.

[0021] The insulating layer 16 has a thickness smaller than that of the metal layer 14 formed in the step (S2) of forming a metal layer described below. The insulating layer 16 may have a thickness less than 12.5 μm, 10 μm or less, or 7 μm or less. This allows the insulating layer 16 on the first portion R1 of the seed layer 13 to be removed in the subsequent step (S13) of irradiating a laser beam, thereby exposing the first portion R1 of the seed layer 13. The insulating layer 16 may have a thickness of 0.5 μm or more, particularly 1 μm or more, from the viewpoint of ensuring sufficient insulation.

[0022] c) Irradiating the insulating layer with a laser beam (S13) The insulating layer 16 on the first portion R1 of the seed layer 13 is irradiated with a laser beam to remove the insulating layer 16 on the first portion R1 of the seed layer 13 by laser ablation. As a result, the first portion R1 of the seed layer 13 is exposed as shown in Fig. 5. Meanwhile, the insulating layer 16 on the second portion R2 of the seed layer 13 remains. The irradiation of the laser beam to the insulating layer 16 may be performed by scanning the insulating layer 16 with the laser beam.

[0023] The laser beam may be a pulsed laser beam. The laser beam may have a wavelength of 580 nm or less and a pulse width of 15 ps or less. As shown in the examples described later, the use of such a laser beam can selectively remove the insulating layer 16. In particular, the wavelength of the laser beam may be 400 nm or less. The pulse width of the laser beam may be 1 ps or less. As shown in the examples described later, the use of such a laser beam can reduce the generation of debris. Furthermore, the use of a UV laser having a wavelength of 400 nm or less facilitates micromachining of the insulating layer 16, and for example, facilitates the formation of a wiring pattern with a line width and spacing (L / S) of 5 μm or less. The wavelength of the laser beam may be 10 nm or more, preferably 250 nm or more. The pulse width of the laser beam may be 0.1 ps or more. Note that the pulse width here is synonymous with the pulse duration and is the full width at half maximum (FW) of the time intensity distribution in a single pulse. HM )

[0024] Various other laser beam irradiation conditions such as frequency, intensity, spot diameter, spatial intensity distribution, and scanning speed may be appropriately set depending on the material and thickness of the insulating layer 16, the material and thickness of the seed layer 13, and the L / S of the wiring pattern of the wiring board to be manufactured. For example, the laser beam may have a top-hat spatial intensity distribution. This can prevent a part of the insulating layer 16 from being melted and remaining without being ablated.

[0025] In this way, a patterned substrate 10 is obtained, which includes an insulating substrate 11, a conductive seed layer 13 provided on the insulating substrate 11, and an insulating layer 16 provided on the seed layer 13. The seed layer 13 is composed of a first portion R1 that is exposed and not covered by the insulating layer 16, and a second portion R2 that is a portion other than the first portion R1, and the insulating layer 16 is provided on the second portion R2. In other words, the second portion R2 of the seed layer 13 is covered by the insulating layer 16.

[0026] (2) Step of forming a metal layer (S2) 6, a metal layer 14 is formed on the first portion R1 of the seed layer 13. Examples of materials for the metal layer 14 include Cu, Ni, Ag, and Au, and Cu may be preferable. The metal layer 14 has a thickness larger than that of the insulating layer 16. The metal layer 14 may have a thickness of, for example, 1 to 100 μm.

[0027] 9 and 10 show an example of a film formation apparatus 50 used to form the metal layer 14. The film formation apparatus 50 includes a metallic anode 51 arranged to face the seed layer 13, a resin film 52 arranged between the anode 51 and the patterned substrate 10, and a power supply unit 54 that applies a voltage between the anode 51 and the seed layer 13.

[0028] The film forming apparatus 50 further includes a housing 53. The housing 53 accommodates an anode 51 and a solution (hereinafter, referred to as a metal solution) L containing ions of a metal that is a material of the metal layer 14. As shown in FIG. 9, the housing 53 may define a space in which the metal solution L is accommodated between the anode 51 and the resin film 52. In this case, the anode 51 may be a plate-shaped member formed of a material (e.g., Cu) that is the same as the material of the metal layer 14 and soluble in the metal solution L, or a plate-shaped member formed of a material (e.g., Ti) that is insoluble in the metal solution L. In the film forming apparatus 50 in which the metal solution L is accommodated between the anode 51 and the resin film 52, the resin film 52 and the patterned substrate 10 can be pressed together with a uniform pressure, so that the metal layer 14 can be uniformly formed on the first portion R1 of the seed layer 13 over the entirety of the patterned substrate 10. Therefore, such a film forming apparatus 50 is suitable for forming a fine wiring pattern.

[0029] Although not shown in the figure, the anode 51 and the resin film 52 may be in contact with each other. In this case, the anode 51 may be formed of a porous body that is permeable to the metal solution L, and the surface of the anode 51 opposite to the surface in contact with the resin film 52 may be in contact with the space in which the metal solution L is accommodated.

[0030] The resin film 52 may be a solid electrolyte film or a porous film.

[0031] Examples of the solid electrolyte membrane include membranes of fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, and resins having a cation exchange function such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd.

[0032] The porous membrane may be, for example, a membrane composed of a polyolefin chain. Here, polyolefin refers to all olefin polymers, including, for example, polyethylene, polypropylene, or a mixture thereof. The polyolefin chain may be crosslinked or non-crosslinked, saturated or unsaturated, and may be linear or branched. The polyolefin chain may be substituted or non-substituted. A preferred embodiment of the polyolefin chain is a crosslinked or non-crosslinked polyethylene chain that does not have a side chain. The porous membrane may not have an ion-exchange functional group.

[0033] The porous membrane may have a pore size of 20 to 2000 nm, or 27 to 1000 nm. When the pore size is within the above range, the metal layer 14 can be formed with high current efficiency. Here, the pore size means the volume average of the pore size distribution. The pore size distribution can be obtained by mercury intrusion porosimetry in accordance with JIS R 1655:2003. The mercury intrusion porosimetry is a method in which mercury is infiltrated into open pores by applying pressure, the relationship between the volume of mercury infiltrated into the open pores and the pressure value applied at that time is obtained, and the diameter of the open pores is calculated based on the result from the Washburn formula assuming that the open pores are cylindrical. The porous membrane has a pore size of 5 to 500 s / 100 cm. 3 Or 10~260s / 100cm 3The porous membrane may have an air permeability of 35 to 90%, or 45 to 80%. The porous membrane may have an air permeability of 35 to 90% ... The porous membrane is 750 to 3000 kgf / cm 2 The porous membrane may have a tensile strength of 5 to 85%, or 1000 to 2400 kgf / cm. The tensile strength within the above range allows for the formation of a flatter metal layer 14. The tensile strength is measured in accordance with JIS K 7127:1999. The porous membrane may have a tensile elongation of 5 to 85%, or 15 to 80%. The tensile elongation within the above range allows for the formation of a flatter metal layer 14. The tensile elongation is measured in accordance with JIS C 2151 or ASTM D882. A commercially available battery separator can be used as the porous membrane. The commercially available separator is less expensive than a solid electrolyte membrane, and further cost reduction is expected.

[0034] When the resin film 52 is brought into contact with the metal solution L, the metal solution L permeates the resin film 52. As a result, the resin film 52 contains the metal solution L inside. The resin film 52 may have a thickness of, for example, about 5 μm to about 200 μm.

[0035] The metal solution L contains the metal (e.g., Cu, Ni, Ag, Au, etc.) in an ionic state, which is the material of the metal layer 14. The metal solution L may contain nitrate ions, phosphate ions, succinate ions, sulfate ions, or pyrophosphate ions. The metal solution L may be an aqueous solution of a metal salt, such as a nitrate, phosphate, succinate, sulfate, or pyrophosphate salt.

[0036] Furthermore, the film forming apparatus 50 includes an elevator 55 for raising and lowering the housing 53, located on the upper portion of the housing 53. The elevator 55 may include, for example, a hydraulic or pneumatic cylinder, an electric actuator, a linear guide, a motor, or the like.

[0037] The housing 53 has a supply port 53a and a discharge port 53b. The supply port 53a and the discharge port 53b are connected to a tank 61 via a pipe 64. The metal solution L pumped out from the tank 61 by a pump 62 connected to the pipe 64 flows into the housing 53 from the supply port 53a, and is discharged from the housing 53 via the discharge port 53b and returned to the tank 61. A pressure regulating valve 63 is provided in the pipe 64 downstream of the discharge port 53b. The pressure of the metal solution L in the housing 53 can be adjusted by the pressure regulating valve 63 and the pump 62.

[0038] The film forming apparatus 50 further includes a metal pedestal 56 on which the patterned substrate 10 is placed, and a conductive member 57 for electrically connecting the seed layer 13 of the patterned substrate 10 to the metal pedestal 56. The conductive member 57 may be a metal plate that covers a part of the edge of the patterned substrate 10 and is partially bent to contact the metal pedestal 56. This electrically connects the metal pedestal 56 to the seed layer 13 via the conductive member 57. The conductive member 57 may be detachable from the patterned substrate 10.

[0039] The negative electrode of the power supply unit 54 is electrically connected to the seed layer 13 via a metal seat 56 , and the positive electrode of the power supply unit 54 is electrically connected to the anode 51 .

[0040] The metal layer 14 can be formed using the film forming apparatus 50 as follows.

[0041] 9, the patterned substrate 10 and the conductive member 57 are placed at a predetermined position on a metal pedestal 56. Then, as shown in FIG. 10, the housing 53 is lowered to a predetermined height by the lifting device 55.

[0042] Next, the metal solution L is pressurized by the pump 62. Then, the pressure regulating valve 63 keeps the metal solution L in the housing 53 at a predetermined pressure. Also, the resin film 52 deforms to conform to the surface of the patterned substrate 10, i.e., the surface of the first portion R1 of the seed layer 13 and the insulating layer 16, and comes into contact with the first portion R1 of the seed layer 13 and the surface of the insulating layer 16. As a result, the metal solution L contained in the resin film 52 comes into contact with the first portion R1 of the seed layer 13 and the surface of the insulating layer 16. The resin film 52 is uniformly pressed against the surface of the first portion R1 of the seed layer 13 and the insulating layer 16 by the pressure of the metal solution L in the housing 53.

[0043] A voltage is applied between the anode 51 and the seed layer 13 by the power supply unit 54. Then, the metal ions contained in the metal solution L in contact with the first portion R1 of the seed layer 13 are reduced on the surface of the first portion R1 of the seed layer 13, and the metal is precipitated on the surface of the first portion R1 of the seed layer 13. On the other hand, the reduction reaction of the metal ions does not occur on the surface of the insulating layer 16, so that the metal is not precipitated. As a result, the metal layer 14 is selectively formed on the first portion R1 of the seed layer 13. The voltage applied between the anode 51 and the seed layer 13 may be appropriately set. By applying a higher voltage, the deposition rate of the metal can be increased. The metal solution L may also be heated. As a result, the deposition rate of the metal can be increased.

[0044] The application of the voltage between the anode 51 and the seed layer 13 is continued until the metal layer 14 having a predetermined thickness exceeding the thickness of the insulating layer 16 is formed. Even after the thickness of the metal layer 14 exceeds the thickness of the insulating layer 16, the thickness of the metal layer 14 can be increased while suppressing an increase in the dimension of the metal layer 14 in the horizontal direction (i.e., the direction perpendicular to the thickness direction of the metal layer 14) (see FIG. 6). That is, the metal layer 14 can have an L / S corresponding to the L / S of the pattern of the first portion R1 of the seed layer 13. Thereafter, the application of the voltage between the anode 51 and the seed layer 13 is stopped, and the pressurization of the metal solution L by the pump 62 is stopped. Then, the housing 53 is raised to a predetermined height (see FIG. 9), and the resin film 52 and the metal layer 14 are separated from each other. The patterned substrate 10 on which the metal layer 14 has been formed is removed from the metal pedestal 56.

[0045] (3) removing the second portion of the insulating layer and the seed layer (S3); As shown in Fig. 7, the insulating layer 16 is removed, and then the second portion R2 of the seed layer 13 is removed as shown in Fig. 8. Thereby, the wiring layer 2 having a predetermined wiring pattern including the first portion R1 of the seed layer 13 and the metal layer 14 is formed on the main surface 11a of the insulating base material 11.

[0046] The insulating layer 16 and the second portion R2 of the seed layer 13 can be removed by etching. The etching method for the insulating layer 16 and the second portion R2 of the seed layer 13 may be either dry or wet. Examples of dry etching include reactive gas etching, sputter etching, plasma etching, ion milling, reactive ion etching (RIE), reactive ion beam etching, radical etching, photoinduced etching, laser-assisted etching, and laser ablation etching. Capacitively coupled plasma (CCP), inductively coupled plasma (ICP), or microwave ECR (Electron Cyclotron Resonance) plasma can be used for the reactive ion etching. The etching gas used for dry etching may be appropriately selected according to the materials of the insulating layer 16 and the second portion R2 of the seed layer 13. Examples of etching gas include CF4, SF6, boron, chlorine, HBr, and BCl3. In wet etching, an acid or alkali solution can be used as an etching solution. The etching solution may be appropriately selected depending on the materials of the insulating layer 16 and the second portion R2 of the seed layer 13.

[0047] In this manner, wiring board 1 is manufactured, which includes insulating base material 11 and wiring layer 2 having a predetermined wiring pattern provided on insulating base material 11.

[0048] In this embodiment, since the metal layer 14 is formed using a film forming apparatus using the resin film 52 as shown in Figures 9 and 10, it is possible to form the metal layer 14 having a thickness greater than that of the insulating layer 16. Therefore, the thickness of the insulating layer 16 can be reduced.

[0049] [Variations] The present invention is not limited to the above-described embodiment, and various design modifications can be made without departing from the spirit of the present invention as defined in the claims. For example, the following modifications are possible.

[0050] First Variation 11, the step (S1) of preparing the patterned substrate 10 includes a step (S11) of forming a seed layer 13, a step (S14) of forming an insulating layer 16, a step (S15) of irradiating the insulating layer 16 with a laser beam (laser light), and a step (S16) of removing the insulating layer 16 on a first portion R1 of the seed layer 13. In the above-described embodiment, in the step (S13) of irradiating the insulating layer 16 with a laser beam, the insulating layer 16 on the first portion R1 of the seed layer 13 is removed by laser ablation, but in this modified embodiment, the insulating layer 16 on the first portion R1 of the seed layer 13 is removed by photolithography using a laser beam (laser photolithography).

[0051] The step (S11) of forming the seed layer 13 is similar to the step (S11) of the above embodiment, and therefore the description will be omitted. In this modified embodiment, the thickness of the seed layer 13 may be appropriately set so that the metal layer 14 is formed uniformly over the entire patterned substrate 10 in the step (S2) of forming the metal layer 14, and so that the manufacturing cost of the wiring board 1 is suppressed.

[0052] In step (S14) of forming the insulating layer 16, a layer of positive or negative resist is formed as the insulating layer 16. Any resist material used in a general photolithography process may be used as the positive or negative resist. The method of forming the insulating layer 16 is similar to the method described in step (S12) of the above embodiment, so a description thereof will be omitted. In this modified embodiment, the thickness of the insulating layer 16 may be appropriately set so that the insulating layer 16 has sufficient insulating properties and can be patterned in the subsequent steps (S15) and (S16).

[0053] In the step (S15) of irradiating the insulating layer 16 with a laser beam, the laser beam is irradiated to either the insulating layer 16 on the first portion R1 or the second portion R2 of the seed layer 13. When the insulating layer 16 is a positive resist layer, the laser beam is irradiated to the insulating layer 16 on the first portion R1 of the seed layer 13, and when the insulating layer 16 is a negative resist layer, the laser beam is irradiated to the insulating layer 16 on the second portion R2 of the seed layer 13.

[0054] The irradiation of the insulating layer 16 with a laser beam may be performed by scanning the insulating layer 16 with the laser beam. The laser beam may be a pulse wave or a continuous wave (CW). Various irradiation conditions of the laser beam, such as the wavelength, intensity, spot diameter, spatial intensity distribution, scanning speed, pulse width, and frequency, may be appropriately set depending on the material and thickness of the insulating layer 16, the L / S of the wiring pattern of the wiring board to be manufactured, and the like. For example, the wavelength of the laser beam may be within a range of 10 to 580 nm, but is not limited thereto.

[0055] Next, the insulating layer 16 on the first portion R1 of the seed layer 13 is dissolved and removed with a developer (step (S16)). As a result, the patterned substrate 10 as shown in FIG. 5 is obtained. The developer is appropriately selected depending on the material of the insulating layer 16.

[0056] Second Variation In this variant, instead of the above-mentioned laser ablation and laser photolithography, other patterning methods (e.g., printing methods such as screen printing, inkjet printing, and transfer printing, and photolithography) are applied as the patterning method for the insulating layer 16.

[0057] Third Variation In this modified embodiment, in the step (S1) of preparing a patterned substrate, a patterned substrate 10 as shown in Fig. 12 is prepared. In Fig. 12, the insulating layer 16 includes a main insulating layer 16a formed on the second portion R2 of the seed layer 13, and a water-repellent layer 16b formed on the main insulating layer 16a. The contact angle of water on the surface of the water-repellent layer 16b may be more than 90 degrees, particularly 120 degrees or more. This can reduce the possibility of metal being deposited on the insulating layer 16 in the step (S2) of forming a metal layer.

[0058] The main insulating layer 16a can be formed in the same manner as the method for forming the insulating layer 16 in the step (S12) of forming the insulating layer in the above embodiment or the step (S14) of forming the insulating layer in the above first modified embodiment.

[0059] Following the formation of the main insulating layer 16a, a water-repellent layer 16b is formed on the main insulating layer 16a. The water-repellent layer 16b may be, for example, a compound represented by the formula SiR n -X 4-n (wherein n is 1, 2, 3, or 4; each R is independently a substituted or unsubstituted alkyl group, phenyl group, trifluoromethyl group, alkylsilyl group, or fluorosilyl group; and each X is independently a hydrogen, halogen, oxygen, or nitrogen; organosilanes of the formula SiR3-(NR-SiR2) m It can be formed using an organic silazane represented by the formula -R (wherein m is an integer of 1 or more, and each R independently represents a substituted or unsubstituted alkyl group, phenyl group, trifluoromethyl group, alkylsilyl group, or fluorosilyl group). Examples of the organic silane include tetraethylsilane, tetramethylsilane, and paraaminophenyltrimethoxysilane. Examples of the organic silazane include hexamethyldisilazane (HMDS).

[0060] The water-repellent layer 16b can be formed by any method such as a dip coating method, a mist coating method, a spray coating method, a CVD method, a LB (Langmuir Blogetto) method, etc. The mist coating method is a method in which a raw material solution containing a metal element is atomized using an ultrasonic vibrator to form a mist, the mist is supplied to a predetermined surface, and the mist is decomposed and / or reacted on the surface by thermal energy or the like, thereby forming a thin film containing a metal element on the surface.

[0061] The insulating layer 16, which includes the main insulating layer 16a and the water-repellent layer 16b, can be patterned by laser ablation, laser photolithography, or other patterning as described in the above embodiments and variations.

[0062] After the patterned main insulating layer 16a is formed by any method, the water-repellent layer 16b may be selectively formed on the main insulating layer 16a. EXAMPLES

[0063] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0064] Example 1 A glass epoxy substrate (glass fiber reinforced epoxy laminate) was prepared as an insulating substrate. A copper film having a thickness of 500 nm was formed as a seed layer on the main surface of the insulating substrate by sputtering. A layer of thermoplastic novolac resin having a thickness of 1.5 to 3 μm was formed as an insulating layer on the seed layer by spin coating. A predetermined region of the insulating layer was scanned once with a spot-shaped laser beam (wavelength 355 nm, pulse width 7 ps) to obtain a patterned substrate with an L / S of 5 μm.

[0065] The cross section of the patterned substrate was observed with a scanning electron microscope (SEM) and it was confirmed that the insulating layer was removed and the seed layer was exposed in the area scanned by the laser beam, and that the seed layer in the area remained in the form of a continuous film. In other words, it was confirmed that the insulating layer could be selectively removed (this result is indicated by "◯" in Table 1).

[0066] A patterned substrate was prepared again under the above conditions, and a Cu layer having a thickness of 5 μm was formed as a metal layer on the exposed surface of the seed layer. Specifically, the Cu layer was formed under the following conditions using the film forming apparatus 50 shown in FIGS.

[0067] Cathode: seed layer Anode: Oxygen-free copper wire Resin film: Nafion (registered trademark) (thickness: approx. 8 μm) Metal solution: 1.0 mol / L copper sulfate aqueous solution Pressure to press the resin film against the seed layer: 1.0 MPa Current density: 0.23mA / cm 2

[0068] Next, the insulating layer was removed by capacitively coupled plasma etching using CF4 gas, and the seed layer was further etched using the metal layer as a mask. As a result, a wiring layer having a predetermined wiring pattern composed of the seed layer and the metal layer was formed on the insulating base material. Thus, a wiring board including the insulating base material and the wiring layer was obtained.

[0069] Example 2 A wiring board was produced in the same manner as in Example 1, except that an insulating layer was formed by attaching a thermoplastic dry film having a thickness of 7 μm to the seed layer.

[0070] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the region scanned with the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that region remained in the form of a continuous film, i.e., it was confirmed that the insulating layer could be selectively removed.

[0071] Comparative Example 1 A patterned substrate was prepared in the same manner as in Example 1, except that an insulating layer was formed by attaching a thermosetting polyimide film having a thickness of 12.5 μm to the seed layer. The cross section of the patterned substrate was observed by SEM. It was confirmed that the insulating layer remained in the region scanned by the laser beam, and the seed layer was not sufficiently exposed. In other words, the insulating layer could not be selectively removed (this result is indicated by "x" in Table 1).

[0072] Examples 3 and 4 A wiring board was produced in the same manner as in Example 1, except that the thickness of the seed layer was as shown in Table 1.

[0073] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the region scanned with the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that region remained in the form of a continuous film, i.e., it was confirmed that the insulating layer could be selectively removed.

[0074] Comparative Examples 2 and 3 A patterned substrate was prepared in the same manner as in Example 1, except that the thickness of the seed layer was as shown in Table 1. The cross section of the patterned substrate was observed by SEM. In the area scanned by the laser beam, not only the insulating layer but also the seed layer was removed, and no seed layer having a sufficient thickness remained. In other words, the insulating layer could not be selectively removed.

[0075] Example 5 A wiring board was produced in the same manner as in Example 1, except that the wavelength and pulse width of the laser beam irradiated onto the insulating layer were as shown in Table 1.

[0076] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the region scanned with the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that region remained in the form of a continuous film, i.e., it was confirmed that the insulating layer could be selectively removed.

[0077] Example 6 A wiring board was produced in the same manner as in Example 1, except that the wavelength and pulse width of the laser beam irradiated onto the insulating layer were as shown in Table 1.

[0078] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the area scanned by the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that area remained in the form of a continuous film. In other words, it was confirmed that the insulating layer could be selectively removed. However, debris, which was a melted and solidified product of the insulating layer, was found on the patterned substrate (this result is indicated by "△" in Table 1).

[0079] Comparative Example 4 A patterned substrate was prepared in the same manner as in Example 2, except that the wavelength and pulse width of the laser beam irradiated to the insulating layer were as shown in Table 1. The cross section of the patterned substrate was observed by SEM. It was confirmed that the insulating layer remained in the region scanned by the laser beam, and the seed layer was not sufficiently exposed. In other words, the insulating layer could not be selectively removed.

[0080] Example 7 A wiring board was produced in the same manner as in Example 1, except that a layer of thermosetting epoxy resin having a thickness of 1.5 to 3 μm was formed as the insulating layer by a spin coating method, and the pulse width of the laser beam irradiated to the insulating layer was set as shown in Table 1.

[0081] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the region scanned with the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that region remained in the form of a continuous film, i.e., it was confirmed that the insulating layer could be selectively removed.

[0082] Example 8 A wiring board was produced in the same manner as in Example 7, except that a layer of thermosetting polyimide resin having a thickness of 1.5 to 3 μm was formed as the insulating layer by spin coating.

[0083] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the region scanned with the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that region remained in the form of a continuous film, i.e., it was confirmed that the insulating layer could be selectively removed.

[0084] Example 9 A wiring board was produced in the same manner as in Example 1, except that the wavelength of the laser beam irradiated onto the insulating layer was as shown in Table 1.

[0085] In addition, when the cross section of the patterned substrate was observed with an SEM, it was confirmed that in the region scanned with the laser beam, the insulating layer was removed to expose the seed layer, and the seed layer in that region remained in the form of a continuous film, i.e., it was confirmed that the insulating layer could be selectively removed.

[0086] Example 10 A wiring board was produced in the same manner as in Example 1, except that the insulating layer in a predetermined region was removed by laser photolithography. Specifically, the laser photolithography was performed by scanning a spot-shaped continuous wave laser beam (wavelength 436 nm) once to expose a predetermined region of the insulating layer, and then dissolving and removing the insulating layer in the predetermined region with a developing solution. In addition, after the Cu layer was formed, cross-sectional SEM observation was performed before the insulating layer was removed. A cross-sectional SEM photograph is shown in FIG. 13. It was confirmed that a Cu layer having a thickness exceeding that of the insulating layer was formed. The Cu layer had a substantially constant width (horizontal dimension) at any height (position in the thickness direction).

[0087] [Table 1] [Explanation of symbols]

[0088] 1: wiring board, 2: wiring layer, 10: patterned substrate, 11: insulating substrate, R1: first portion, R2: second portion, 13: seed layer, 14: metal layer, 16: insulating layer, 50: film forming device, 51: anode, 52: resin film, L: solution containing metal ions (metal solution)

Claims

1. A method for manufacturing a wiring board including an insulating base material and a wiring layer having a predetermined wiring pattern provided on the insulating base material, comprising: (a) providing a patterned substrate, comprising: wherein the patterned substrate is The insulating substrate; a conductive seed layer having a thickness of 80 nm or more provided on the insulating base material, the conductive seed layer including a first portion having a predetermined pattern corresponding to the wiring pattern and a second portion other than the first portion; an insulating layer disposed on the second portion of the seed layer and having a thickness of less than 12.5 μm; the insulating layer comprises a main insulating layer provided on the second portion of the seed layer and a water-repellent layer provided on the main insulating layer, the water-repellent layer having a surface with a water contact angle of greater than 90 degrees; The step (a) forming the insulating layer over the first and second portions of the seed layer; irradiating the insulating layer on a first portion with a laser beam having a wavelength of 355 nm or less and a pulse width of 7 ps or less to remove the insulating layer on the first portion; and (b) forming a metal layer on a first portion of the seed layer, the top surface of the metal layer being higher than the top surface of the insulating layer; a step of disposing a solid electrolyte film containing metal ions between the patterned substrate and an anode, and applying a voltage between the anode and the seed layer while pressing the solid electrolyte film and the seed layer together; (c) removing the insulating layer and a second portion of the seed layer; A method comprising:

2. The method of claim 1 , wherein the laser beam has a pulse width of 1 ps or less.

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