WO2011001900A1 - Printed-wiring board and process for manufacture thereof - Google Patents

Printed-wiring board and process for manufacture thereof Download PDF

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Publication number
WO2011001900A1
WO2011001900A1 PCT/JP2010/060776 JP2010060776W WO2011001900A1 WO 2011001900 A1 WO2011001900 A1 WO 2011001900A1 JP 2010060776 W JP2010060776 W JP 2010060776W WO 2011001900 A1 WO2011001900 A1 WO 2011001900A1
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WO
WIPO (PCT)
Prior art keywords
insulating layer
laser beam
opening
masking film
wiring board
Prior art date
Application number
PCT/JP2010/060776
Other languages
French (fr)
Japanese (ja)
Inventor
芳奈 宮崎
周一郎 安田
Original Assignee
ソニーケミカル＆インフォメーションデバイス株式会社
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Publication of WO2011001900A1 publication Critical patent/WO2011001900A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/0011—Working of insulating substrates or insulating layers
    • H05K3/0017—Etching of the substrate by chemical or physical means
    • H05K3/0026—Etching of the substrate by chemical or physical means by laser ablation
    • H05K3/0032—Etching of the substrate by chemical or physical means by laser ablation of organic insulating material
    • H05K3/0038—Etching of the substrate by chemical or physical means by laser ablation of organic insulating material combined with laser drilling through a metal layer
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
    • H05K3/4038—Through-connections; Vertical interconnect access [VIA] connections
    • H05K3/4053—Through-connections; Vertical interconnect access [VIA] connections by thick-film techniques
    • H05K3/4069—Through-connections; Vertical interconnect access [VIA] connections by thick-film techniques for via connections in organic insulating substrates
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/095—Conductive through-holes or vias
    • H05K2201/09509—Blind vias, i.e. vias having one side closed
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/01—Tools for processing; Objects used during processing
    • H05K2203/0191—Using tape or non-metallic foil in a process, e.g. during filling of a hole with conductive paste
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/05—Patterning and lithography; Masks; Details of resist
    • H05K2203/0562—Details of resist
    • H05K2203/0568—Resist used for applying paste, ink or powder
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/10—Using electric, magnetic and electromagnetic fields; Using laser light
    • H05K2203/107—Using laser light
    • H05K2203/108—Using a plurality of lasers or laser light with a plurality of wavelengths
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/13—Moulding and encapsulation; Deposition techniques; Protective layers
    • H05K2203/1377—Protective layers
    • H05K2203/1383—Temporary protective insulating layer
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/14—Related to the order of processing steps
    • H05K2203/1461—Applying or finishing the circuit pattern after another process, e.g. after filling of vias with conductive paste, after making printed resistors

Definitions

  • the present invention relates to a printed wiring board in which a plurality of circuit wirings are stacked with an insulating layer interposed therebetween, and the circuit wirings of each layer are connected via an interlayer connection portion of a via hole, and a manufacturing method thereof.
  • a via hole having a conductive material provided therein is formed through the insulating layer.
  • a method of filling a via hole formed in the insulating layer with copper plating or conductive paste is used.
  • an interlayer connection method using a conductive paste is excellent in that the environmental load during manufacturing is small and the manufacturing method is simple.
  • this interlayer connection method uses a masking film such as PET on a copper foil 2 on the surface side of a double-sided copper-clad plate 4 in which copper foils 2 and 3 are adhered to both surfaces of an insulating layer 1 such as polyimide.
  • 5 is pasted (a), and a via hole 6 is formed at a predetermined position of the copper foil 2 using UV laser light or the like (b).
  • the conductive paste 8 is filled in the via hole 6 and temporarily cured (c).
  • the masking film 5 is peeled off (d) and hot-pressed to form an interlayer connection structure with the conductive paste 8.
  • a resist material (not shown) is applied or pasted on the copper foils 2 and 3, a predetermined circuit pattern is exposed, the resist other than the circuit pattern portion is removed, and a predetermined circuit pattern is formed on the copper foils 2 and 3.
  • an interlayer connection structure using the conductive paste 8 is completed (e).
  • films are attached to both surfaces of a prepreg sheet, through holes are formed by laser light, and after filling the through holes with conductive paste, the film is peeled off.
  • interlayer connection method in which metal foils are attached to both sides of a prepreg sheet and hot pressed to connect the metal foils on both sides.
  • the conductive paste expresses electrical conductivity by contact between conductive particles such as silver and copper in the resin, and the conductive paste filled in the metal foil and through-hole of the circuit on the substrate.
  • the contact area with the adhesive paste is small, or the resistance value increases depending on other contact states.
  • the area of the contact portion has become extremely small and the circuit resistance tends to increase.
  • the contact between the conductive paste and the circuit metal foil may be impaired, the contact resistance will increase, and good conductive properties may not be obtained. there were.
  • the metal foil of the circuit becomes thinner and the shape becomes smaller, so the contact area with the conductive paste decreases, the resistance increases, and the reliability of electrical conduction decreases It was something to do.
  • a through hole is formed in a substrate of an insulating layer provided with a metal foil for forming a circuit, and a conductive paste filled in the through hole is used to connect the front and back of the substrate.
  • This is an electrical connection of the metal foil, and a concave surface is formed on the end face of the metal foil located at the periphery of the through hole, and the contact area between the filled conductive paste and the metal foil is increased to ensure the contact state.
  • the interlayer connection method disclosed in Patent Document 3 is such that a masking film is applied as a mask for printing on one side of a copper foil for circuit formation of a double-sided printed wiring board in which via holes are filled with a conductive paste for interlayer conduction. wear.
  • a via hole When forming the via hole, first, an opening having an opening diameter larger than the via diameter is opened in the masking film by laser irradiation. Next, a via hole having a diameter smaller than that of the opening is formed in the opening by laser light. At this time, through holes are formed in the insulating layer together with the copper foil on the front surface, and the copper foil on the back surface is exposed in the via hole.
  • the via hole is filled with a conductive paste
  • the masking film is peeled off, and the filled conductive paste is hot-pressed and cured.
  • it is a method for manufacturing a double-sided printed wiring board in which a resist is applied to a copper foil on the surface, a predetermined circuit pattern is exposed, a resist other than the circuit pattern is removed and etched to form a circuit.
  • a large opening is first formed in the masking film, a via hole having a small diameter is formed inside the masking film, and the contact area between the copper foil forming the circuit and the conductive paste in the via hole is increased. Yes.
  • the interlayer connection structure disclosed in Patent Document 1 includes a process of attaching a metal foil after filling a through hole with a conductive paste, which complicates the process, and when forming a land portion of a circuit using the metal foil In addition, it is difficult to align with the position of the conductive paste for interlayer connection, and it is difficult to apply to a wiring board having a fine circuit pattern. Further, the interlayer connection method disclosed in Patent Document 2 is difficult to form a recess in the end face of the surface metal foil, and cannot be applied to a thin metal foil or a fine circuit pattern.
  • This invention makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, it is an object of the present invention to provide a printed wiring board and a method for manufacturing the same, in which interlayer connection by a conductive paste is reliably performed, electrical resistance is low, and connection reliability is high.
  • Means for solving the above problems are as follows. That is, ⁇ 1> An insulating layer, circuit wiring using metal foil formed on both surfaces of the insulating layer, and vias provided in the insulating layer are electrically connected to the circuit wiring formed on both surfaces of the insulating layer.
  • a masking film is attached to a circuit wiring surface on one side of the insulating layer, and a first laser beam is applied to the surface on which the masking film is attached.
  • the masking film and the circuit wiring on one side of the insulating layer are formed with an opening, and a spot having a spot diameter larger than the diameter of the ridge line of the raised portion formed at the periphery of the opening of the masking film is formed.
  • ⁇ 3> The print according to any one of ⁇ 1> to ⁇ 2>, wherein a diameter of the opening of the masking film by the first laser beam is larger than a diameter of the opening of the circuit wiring on one side of the insulating layer. It is a manufacturing method of a wiring board.
  • ⁇ 4> The via hole is formed by penetrating the insulating layer by the second laser light with the circuit wiring on one side of the insulating layer having the opening formed by the first laser light as a mask.
  • To ⁇ 3>. The method for producing a printed wiring board according to any one of ⁇ 3>.
  • the second laser beam having a spot diameter larger than the diameter of the ridge line at the periphery of the opening formed in the masking film by the first laser beam is formed on one side of the circuit wiring opening.
  • the via hole is formed by irradiating the opening of the circuit wiring on one side of the insulating layer, and the conductive paste is formed at the periphery of the via hole formed by the second laser beam.
  • the printed wiring board is laminated on the surface of the circuit wiring in an inner portion of the masking film opening.
  • the conductive paste is surely filled in the through holes connecting the circuits of the respective layers of the printed wiring board, and the conductive paste and the metal foil forming the circuit are joined. Area and bonding strength are increased. Thereby, the electrical resistance of the interlayer connection by the conductive paste is low and the connection reliability is high, and the reliability of the electrical connection against heat cycle, thermal shock and the like is also high. And the environmental resistance performance and durability of an electronic device are improved, and the increase in cost is also reduced.
  • FIG. 1A is a schematic cross-sectional view illustrating a manufacturing process of a printed wiring board according to an embodiment of the present invention (part 1).
  • FIG. 1: B is schematic sectional drawing which showed the manufacturing process of the printed wiring board of one Embodiment of this invention (the 2).
  • FIG. 1: C is schematic sectional drawing which showed the manufacturing process of the printed wiring board of one Embodiment of this invention (the 3).
  • FIG. 1D is a schematic cross-sectional view showing the manufacturing process of the printed wiring board according to the embodiment of the present invention (No. 4).
  • FIG. 2A is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (No. 1).
  • FIG. 1: B is schematic sectional drawing which showed the manufacturing process of the printed wiring board of one Embodiment of this invention (the 2).
  • FIG. 1: C is schematic sectional drawing which showed the manufacturing process of the printed wiring board of one Embodiment
  • FIG. 2B is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (part 2).
  • FIG. 2C is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (No. 3).
  • FIG. 2D is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (No. 4).
  • FIG. 3A is a schematic cross-sectional view showing a manufacturing process of a conventional printed wiring board (No. 1).
  • FIG. 3: B is schematic sectional drawing which showed the manufacturing process of the conventional printed wiring board (the 2).
  • FIG. 1 is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (part 2).
  • FIG. 2C is a schematic cross-
  • FIG. 3 C is schematic sectional drawing which showed the manufacturing process of the conventional printed wiring board (the 3).
  • FIG. 3D is a schematic cross-sectional view showing the manufacturing process of the conventional printed wiring board (No. 4).
  • FIG. 3E is a schematic cross-sectional view showing the manufacturing process of the conventional printed wiring board (No. 5).
  • FIG. 4 is a schematic cross-sectional view showing a method for manufacturing a printed wiring board of a comparative example of the present invention.
  • the method for producing a printed wiring board of the present invention includes at least a masking film attaching step, an opening forming step, a via hole forming step, and a conductive paste filling step, and further appropriately selected as necessary. These steps are included.
  • the masking film attaching step is a step of attaching a masking film to the circuit wiring surface on one side of the insulating layer.
  • ⁇ Masking film ⁇ There is no restriction
  • a lamination method of the said mask film According to the objective, it can select suitably, For example, a vacuum lamination method etc. are mentioned.
  • the masking film is directly affixed to a copper foil with no circuit formed thereon, it can be easily and satisfactorily affixed with a uniform surface and no irregularities or steps.
  • the material of the insulating layer is not particularly limited as long as it has insulating properties, and can be appropriately selected according to the purpose.
  • polyimide is preferable.
  • ⁇ Circuit wiring ⁇ There is no restriction
  • the opening forming step is a step of forming an opening in the circuit wiring on one side of the masking film and the insulating layer by irradiating the surface on which the masking film is attached with a first laser beam.
  • First laser beam There is no restriction
  • the via hole forming step is a step of forming the via hole in the insulating layer with a second laser beam having a spot diameter larger than the diameter of the ridge line of the raised portion formed at the periphery of the opening of the masking film.
  • a second laser beam having a spot diameter larger than the diameter of the ridge line of the raised portion formed at the periphery of the opening of the masking film.
  • the second laser beam is not particularly limited and may be appropriately selected depending on the purpose, for example, CO 2 laser, YAG lasers and the like.
  • the second laser preferably has a lower energy density than the first laser.
  • ⁇ Ridge of the ridge formed on the periphery of the opening The raised portion has a ring shape that rises at the periphery of the opening of the masking film.
  • the ridge line of the raised portion is a line connecting the vertices of the raised portion.
  • a measuring method of the diameter of the said ridgeline According to the objective, it can select suitably, For example, the cross-sectional observation using a microscope, the measuring method by surface observation, etc. are mentioned.
  • the conductive paste filling step is a step of filling the via holes with the conductive paste and electrically connecting the circuit wirings.
  • the conductive paste is not particularly limited and may be appropriately selected depending on the purpose as long as the metal particles of the high melting point metal and the low melting point metal are mixed in the thermoplastic resin and alloyed by the subsequent heat treatment. be able to.
  • the refractory metal is not particularly limited and may be appropriately selected depending on the purpose. For example, particles containing at least copper (one or more particles of copper, gold, silver, zinc, and nickel) Alloy particles containing metal and copper), and the like. The surface of the metal particles may be coated with gold, silver, zinc, nickel, or an alloy thereof by plating or the like.
  • the average particle diameter of the metal particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably about 1 ⁇ m to about 10 ⁇ m (for example, 6 ⁇ m).
  • grains of Sn (for example, solder) containing Sn, etc. are mentioned.
  • the solder is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include Sn—Cu solder, Sn—Ag solder, Sn—Ag—Cu solder, In, Zn, Bi Any one or more of these may be added and further mixed as appropriate.
  • the binder resin of the conductive paste is not particularly limited as long as it is a thermoplastic resin, and can be appropriately selected according to the purpose.
  • -Filling method of conductive paste- There is no restriction
  • circuit wirings 13 a and 14 a made of copper foils 13 and 14 that are metal foils are formed on both surfaces of an insulating layer 12.
  • the insulating layer 12 is made of an insulating substrate such as polyimide, and has copper foils 13 and 14 attached to both sides.
  • the copper foils 13 and 14 on the front and back surfaces of the insulating layer 12 are formed in a predetermined circuit pattern through the steps described later, and constitute circuit wirings 13a and 14a.
  • Via holes 16 are formed in the insulating layer 12 to electrically connect the circuit wirings 13a and 14a on the front and back sides, and the circuit wirings 13a and 14a on the front and back sides are connected by an interlayer connection member made of a conductive paste 18. .
  • the masking film 24 is affixed on the one side surface in which the copper foil 13 of the double-sided copper-clad board 22 which used polyimide etc. as the board
  • the double-sided copper-clad plate 22 is irradiated with UV laser light L1 such as an excimer laser from the masking film 24 side to form an opening 26 in the masking film 24 and simultaneously form an opening 28 in the copper foil 13.
  • UV laser light L1 such as an excimer laser from the masking film 24 side
  • a raised annular ridge 26 a is formed on the periphery of the opening 26 of the masking film 24.
  • This laser processing is a known method called a copper direct method.
  • the diameter D1 of the circle formed by the ridge line of the raised portion 26a is larger than the diameter D2 of the opening 28 of the copper foil 13. That is, there is always a relationship of D1> D2.
  • the diameter D0 of the opening 26 of the masking film 24 by the laser light L1 is larger than the diameter D2 of the opening 28 of the copper foil 13. That is, there is a relationship of D0> D2, and a relationship of D1> D0> D2 is always established.
  • a via hole 16 is formed in the insulating layer 12.
  • the via hole 16 is also formed by a laser beam L2 such as a CO 2 laser beam or a YAG laser.
  • the spot diameter D3 of the laser beam L2 at this time is larger than the diameter D1 of the ridge line of the raised portion 26a of the masking film 24 (FIG. 1C). That is, there is a relationship of D3> D1.
  • the peripheral edge portion 28a of the opening portion 28 of the copper foil 13 is exposed inside the opening portion 27 having an expanded diameter D3.
  • the via hole 16 is masked by the opening 28 of the copper foil 13 and formed with an opening having a diameter D2.
  • the output of the laser beam L2 is adjusted so as not to penetrate the copper foil 14 on the back surface side. Therefore, the laser beam L2 has a spot diameter larger than that of the UV laser beam L1, and the energy density, that is, the intensity of the light is smaller than that of the UV laser beam L1.
  • the inside of the via hole 16 is desmeared, and the conductive paste 18 is filled into the via hole 16 as shown in FIG. 2A.
  • the masking film 24 is peeled off, and the double-sided copper-clad plate 22 is hot-pressed to melt and cure the conductive paste 18 to achieve electrical connection between the copper foils 13 and 14. .
  • a dry film 30 of an etching resist is attached to the copper foils 13 and 14 on the front and back surfaces forming the circuit wirings 13a and 14a (FIG. 2C), exposed to a predetermined circuit pattern and etched, as shown in FIG. 2D.
  • circuit wirings 13a and 14a are formed.
  • the interlayer connection member made of the conductive paste 18 also adheres to the peripheral portion 28a of the opening 28 of the copper foil 13 located at the peripheral edge of the via hole 16, and is reliable and has low resistance. Interlayer connection is possible.
  • the small-diameter via hole 16 can be formed by a simple process, and the conductive paste 18 can be reliably filled into the via hole 16. it can. This is because the secondary agglomerated particles of the dispersed metal particles are not prevented from being filled by the expanded openings 27 of the masking film 24, so that a sufficient amount of the conductive paste 18 is filled in the via holes 16. It is believed that there is.
  • the electrical connection of the interlayer connection part is reliable and high in strength, the reliability of the electrical connection against heat cycle, thermal shock, etc. is improved, the environmental resistance performance and durability of the electronic device to be used are improved, Moreover, the increase in cost is small.
  • the above relationship D3> D1 is essential.
  • the diameter D0 of the opening 26 of the masking film 24 is larger than the diameter D2 of the opening 28 of the copper foil 13 (D0> D2)
  • the spot diameter D3 of the laser light L2 is larger than the diameter D2.
  • Is larger (D3> D2) when the spot diameter D3 of the laser beam L2 is smaller than the diameter D1 of the ridge line of the raised portion 26a of the masking film 24 (D1> D3), the above-described effects are not exhibited. This is because the raised portion 26 a remains even by irradiation with the laser beam L 2, and the conductive paste 18 cannot sufficiently contact the periphery of the opening 28 of the copper foil 13.
  • the printed wiring board and the manufacturing method thereof according to the present invention are not limited to the above embodiment, and the type of conductive paste filled in the via hole can be selected as appropriate, and is laminated on the printed wiring board.
  • the number of layers of the wiring board can also be set as appropriate.
  • the thickness and material of the insulating layer can be set as appropriate, and the type, irradiation diameter, and irradiation method of the laser light can also be set as appropriate.
  • Example 1 a PET masking film was attached to one surface of a double-sided copper-clad polyimide substrate. And the opening part was formed in the masking film and copper foil by the copper direct method from the surface by the side of a masking film using UV laser beam.
  • the value of the diameter D1 is a value obtained by selecting five openings from the 40,000 openings formed on the double-sided copper-clad plate and calculating an average value.
  • via holes were formed in the polyimide substrate with a YAG laser.
  • desmear treatment was performed, the conductive paste was filled, dried, the masking film was peeled off, and hot pressing was performed. Then, the conductive paste was cured by hot pressing, and the conductive paste was compressed in the via hole, and then the copper foil was patterned.
  • daisy chain patterning was performed for resistance measurement.
  • an opening having a diameter of the edge of the opening of 97 ⁇ m was formed on the masking film by UV laser light, and an opening was also formed on the copper foil.
  • a via hole was formed in the polyimide substrate with a laser beam having a spot diameter of 60 ⁇ m in the opening of the masking film.
  • the masking film was peeled off through the same process as described above, and the conductive paste was filled and patterned.
  • Example 1 of the present invention had a lower resistance value and less variation in resistance value.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
  • Production Of Multi-Layered Print Wiring Board (AREA)

Abstract

A process for manufacturing a printed-wiring board having an insulating layer, circuit wirings formed from a metal foil on both surfaces of the insulating layer, and conductive paste filled in a via hole for electrically connecting the circuit wirings formed on both surfaces of the insulating layer. The process comprises steps of sticking a masking film on the surface of the circuit wiring on one side of the insulating layer, projecting a first laser beam onto the surface of the stuck masking film to form an aperture through the masking film and through the circuit wiring on one side of the insulating layer, projecting a second laser beam having a spot-diameter larger than the diameter of a ridgeline of a rise caused around the aperture in the masking film to form the via hole through the insulating layer, and filling the conductive paste into the via hole for electrically connecting the circuit wirings.

Description

プリント配線板及びその製造方法Printed wiring board and manufacturing method thereof
　本発明は、複数の回路配線が絶縁層を挟んで積層され、各層の回路配線がビアホールの層間接続部を介して接続されたプリント配線板及びその製造方法に関する。 The present invention relates to a printed wiring board in which a plurality of circuit wirings are stacked with an insulating layer interposed therebetween, and the circuit wirings of each layer are connected via an interlayer connection portion of a via hole, and a manufacturing method thereof.
　従来、多層プリント配線板において絶縁層で絶縁された各回路配線を電気的に接続するため、内部に導電材が設けられたビアホールが絶縁層を貫通して形成されている。この層間接続には、絶縁層に形成されたビアホール内に、銅メッキや導電性ペーストを充填する方法が用いられている。特に、導電性ペーストを用いた層間接続方法は、製造時の環境負荷が小さく、製造方法が簡易である点で優れている。 Conventionally, in order to electrically connect each circuit wiring insulated by an insulating layer in a multilayer printed wiring board, a via hole having a conductive material provided therein is formed through the insulating layer. For the interlayer connection, a method of filling a via hole formed in the insulating layer with copper plating or conductive paste is used. In particular, an interlayer connection method using a conductive paste is excellent in that the environmental load during manufacturing is small and the manufacturing method is simple.
　この層間接続方法は、図３に示すように、ポリイミド等の絶縁層１の両面に銅箔２，３が貼付された両面銅張り板４の表面側の銅箔２に、ＰＥＴ等のマスキングフィルム５を貼り付け（ａ）、銅箔２の所定位置にＵＶレーザ光等を用いてビアホール６を形成する（ｂ）。このとき、マスキングフィルム５と銅箔２、及び絶縁層１に順次開口部や透孔を形成する方法や、同時に貫通孔を形成する方法もある。次に、ビアホール６内に導電性ペースト８を充填し、仮硬化させる（ｃ）。この後、マスキングフィルム５を剥がして（ｄ）、熱プレスし、導電性ペースト８による層間接続構造を形成する。次に、銅箔２，３に図示しないレジスト材料を塗布又は貼り付け、所定の回路パターンを露光し、回路パターン部以外のレジストを除去し、銅箔２，３に所定の回路パターンを形成し、導電性ペースト８による層間接続構造を完成するものである（ｅ）。 As shown in FIG. 3, this interlayer connection method uses a masking film such as PET on a copper foil 2 on the surface side of a double-sided copper-clad plate 4 in which copper foils 2 and 3 are adhered to both surfaces of an insulating layer 1 such as polyimide. 5 is pasted (a), and a via hole 6 is formed at a predetermined position of the copper foil 2 using UV laser light or the like (b). At this time, there are a method of sequentially forming openings and through holes in the masking film 5, the copper foil 2, and the insulating layer 1, and a method of simultaneously forming through holes. Next, the conductive paste 8 is filled in the via hole 6 and temporarily cured (c). Thereafter, the masking film 5 is peeled off (d) and hot-pressed to form an interlayer connection structure with the conductive paste 8. Next, a resist material (not shown) is applied or pasted on the copper foils 2 and 3, a predetermined circuit pattern is exposed, the resist other than the circuit pattern portion is removed, and a predetermined circuit pattern is formed on the copper foils 2 and 3. Then, an interlayer connection structure using the conductive paste 8 is completed (e).
　その他、特許文献１に開示されているように、プリプレグシートの両面にフィルムを貼り付けて、レーザ光により貫通孔を形成し、この貫通孔に導電性ペーストを充填した後、フィルムを剥離して、プリプレグシートの両面に金属箔を貼り付けて熱プレスし、両面の金属箔を接続する層間接続方法もある。 In addition, as disclosed in Patent Document 1, films are attached to both surfaces of a prepreg sheet, through holes are formed by laser light, and after filling the through holes with conductive paste, the film is peeled off. There is also an interlayer connection method in which metal foils are attached to both sides of a prepreg sheet and hot pressed to connect the metal foils on both sides.
　しかし、導電性ペーストは、樹脂中の銀や銅等の導電性粒子同士の接触によって、電気伝導性を発現しているものであり、基板上の回路の金属箔と貫通孔に充填された導電性ペーストとの接触面積が小さかったり、その他接触状態により抵抗値が大きくなる場合があった。さらに、近年の回路構成の高密度化や小型化により、接触部分の面積がきわめて小さくなり、回路抵抗が増加する傾向にあった。また、ヒートサイクル等の環境変化によって、基板に繰り返しの応力が発生すると、導電性ペーストと回路用金属箔との接触が損なわれ、接触抵抗が増加し、良好な導電特性が得られなくなる場合があった。特に、多層回路基板等の回路の微細化に伴って回路の金属箔が薄くなり形状も小さくなるので、導電性ペーストとの接触面積が減少し、抵抗が増大し電気的導通の信頼性が減少するものであった。 However, the conductive paste expresses electrical conductivity by contact between conductive particles such as silver and copper in the resin, and the conductive paste filled in the metal foil and through-hole of the circuit on the substrate. In some cases, the contact area with the adhesive paste is small, or the resistance value increases depending on other contact states. Furthermore, due to the recent increase in density and miniaturization of circuit configurations, the area of the contact portion has become extremely small and the circuit resistance tends to increase. Also, if repeated stress occurs on the substrate due to environmental changes such as heat cycle, the contact between the conductive paste and the circuit metal foil may be impaired, the contact resistance will increase, and good conductive properties may not be obtained. there were. In particular, as circuit miniaturization of multilayer circuit boards, etc., the metal foil of the circuit becomes thinner and the shape becomes smaller, so the contact area with the conductive paste decreases, the resistance increases, and the reliability of electrical conduction decreases It was something to do.
　そこで、特許文献２に開示された層間接続方法では、回路を形成する金属箔が設けられた絶縁層の基板に貫通孔が形成され、この貫通孔内に充填された導電性ペーストにより基板表裏の金属箔の電気的接続を行うものであって、貫通孔の周縁に位置した金属箔の端面に凹面を形成し、充填された導電性ペーストと金属箔との接触面積を増大させ接触状態を確実にするものが提案されている。 Therefore, in the interlayer connection method disclosed in Patent Document 2, a through hole is formed in a substrate of an insulating layer provided with a metal foil for forming a circuit, and a conductive paste filled in the through hole is used to connect the front and back of the substrate. This is an electrical connection of the metal foil, and a concave surface is formed on the end face of the metal foil located at the periphery of the through hole, and the contact area between the filled conductive paste and the metal foil is increased to ensure the contact state. Something has been proposed.
　また、特許文献３に開示された層間接続方法は、ビアホールに層間導通のための導電性ペーストを充填した両面プリント配線板の、回路形成する銅箔の片面に、印刷用マスクとしてマスキングフィルムを貼り付ける。そして、ビアホールを形成する際に、まず、レーザ照射により、開口径がビア径よりも大きい開口部を該マスキングフィルムに開ける。次に、その開口部よりも小さい径のビアホールをその開口部内にレーザ光により形成する。このとき、表面の銅箔とともに絶縁層にも透孔を形成し、裏面の銅箔をビアホール内に露出させる。この後、ビアホール内に導電性ペーストを充填し、マスキングフィルムを剥がして、充填した導電性ペーストを熱プレスして硬化させる。さらに、表面の銅箔にレジストを塗布し、所定の回路パターンを露光し、回路パターン以外のレジストを除去してエッチングし回路形成を行う両面プリント配線板の製造方法である。この製法では、初めにマスキングフィルムに大きな開口を形成しておいて、その内側に小さい径のビアホールを形成し、回路を形成した銅箔とビアホール内の導電性ペーストとの接触面積を大きくしている。 In addition, the interlayer connection method disclosed in Patent Document 3 is such that a masking film is applied as a mask for printing on one side of a copper foil for circuit formation of a double-sided printed wiring board in which via holes are filled with a conductive paste for interlayer conduction. wear. When forming the via hole, first, an opening having an opening diameter larger than the via diameter is opened in the masking film by laser irradiation. Next, a via hole having a diameter smaller than that of the opening is formed in the opening by laser light. At this time, through holes are formed in the insulating layer together with the copper foil on the front surface, and the copper foil on the back surface is exposed in the via hole. Thereafter, the via hole is filled with a conductive paste, the masking film is peeled off, and the filled conductive paste is hot-pressed and cured. Furthermore, it is a method for manufacturing a double-sided printed wiring board in which a resist is applied to a copper foil on the surface, a predetermined circuit pattern is exposed, a resist other than the circuit pattern is removed and etched to form a circuit. In this manufacturing method, a large opening is first formed in the masking film, a via hole having a small diameter is formed inside the masking film, and the contact area between the copper foil forming the circuit and the conductive paste in the via hole is increased. Yes.
　しかしながら、従来の方法ではレーザ光により形成されたマスキングフィルムの開口部周縁部が隆起したり、マスキングフィルムの開口径がビアホール径より小さくなったりして、導電性ペーストの充填が阻害されるという問題があった。これは、マスキングフィルムの開口が狭いと、導電ペースト中に分散された金属粒子の２次凝集粒子が充填工程において、開口部からの導電性ペーストの侵入を阻害するためであると考えられる。さらに、開口部の隆起部周辺にペースト溜り等が形成される場合もあり、開口部内への充填が阻害されるためと考えられる。 However, in the conventional method, there is a problem that the peripheral edge of the opening of the masking film formed by the laser beam is raised, or the opening diameter of the masking film is smaller than the diameter of the via hole, so that filling of the conductive paste is hindered. was there. This is considered to be because when the opening of the masking film is narrow, the secondary aggregated particles of the metal particles dispersed in the conductive paste inhibit the intrusion of the conductive paste from the opening in the filling step. Furthermore, a paste pool or the like may be formed in the vicinity of the raised portion of the opening, which is considered to be an obstacle to filling the opening.
　また、上記特許文献１に開示された層間接続構造は、導電性ペーストを貫通孔に充填した後、金属箔を貼り付ける工程があり、工程が複雑になり、金属箔による回路のランド部形成時に、層間接続する導電性ペーストの位置と位置合わせが難しく、微細な回路パターンの配線板には適用し難いものである。また、特許文献２に開示された層間接続方法は、表面の金属箔の端面に凹部を形成する工程が難しく、薄い金属箔や微細な回路パターンには適用できないものである。さらに、特許文献３に開示された層間接続方法の場合、レーザ光によりマスキングフィルムに開口を形成した後、その開口径よりも小さい開口径の孔をレーザ光により金属箔に形成し、さらに絶縁層にもレーザ光により貫通孔を形成するものである。この後、導電性ペーストを充填し、表裏の金属箔を電気的に接続するものであり、製造工程が多く、マスキングフィルムに形成する当初の開口に対して後のレーザ光による影響を抑えるため等により、開口が大きくなり、微細な回路パターンには適用できないものである。 In addition, the interlayer connection structure disclosed in Patent Document 1 includes a process of attaching a metal foil after filling a through hole with a conductive paste, which complicates the process, and when forming a land portion of a circuit using the metal foil In addition, it is difficult to align with the position of the conductive paste for interlayer connection, and it is difficult to apply to a wiring board having a fine circuit pattern. Further, the interlayer connection method disclosed in Patent Document 2 is difficult to form a recess in the end face of the surface metal foil, and cannot be applied to a thin metal foil or a fine circuit pattern. Furthermore, in the case of the interlayer connection method disclosed in Patent Document 3, after forming an opening in the masking film with a laser beam, a hole having an opening diameter smaller than the opening diameter is formed in the metal foil with the laser beam, and further an insulating layer In addition, a through hole is formed by laser light. After this, the conductive paste is filled and the metal foils on the front and back are electrically connected, and there are many manufacturing processes to suppress the influence of the subsequent laser light on the initial opening formed in the masking film, etc. As a result, the aperture becomes large and cannot be applied to a fine circuit pattern.
特許第２８７４５８１号公報Japanese Patent No. 2874581 特開２００３－１８８５３３号公報JP 2003-188533 A 特開２００７－２８１３３６号公報JP 2007-281336 A
　本発明は、従来における前記諸問題を解決し、以下の目的を達成することを課題とする。即ち、導電性ペーストによる層間接続が確実に行われ、電気抵抗が低く接続の信頼性も高いプリント配線板及びその製造方法を提供することを目的とする。 This invention makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, it is an object of the present invention to provide a printed wiring board and a method for manufacturing the same, in which interlayer connection by a conductive paste is reliably performed, electrical resistance is low, and connection reliability is high.
　前記課題を解決するための手段としては以下の通りである。即ち、
＜１＞　絶縁層と、前記絶縁層の両面に形成された金属箔による回路配線と、前記絶縁層に設けられたビアホールに充填され、前記絶縁層の両面に形成された各回路配線を電気的に接続する導電性ペーストとを有するプリント配線板の製造方法において、前記絶縁層の一方の側の回路配線表面にマスキングフィルムを貼り付け、前記マスキングフィルムが貼り付けられた面に第１のレーザ光を照射して、前記マスキングフィルム及び前記絶縁層の一方の側の回路配線に開口部を形成し、前記マスキングフィルムの開口部周縁に形成された隆起部の稜線の直径よりも大きなスポット径の第２のレーザ光により、前記絶縁層に前記ビアホールを形成し、前記ビアホールに前記導電性ペーストを充填して前記各回路配線を電気的に接続することを含むことを特徴とするプリント配線板の製造方法である。
＜２＞　第２のレーザ光は、第１のレーザ光よりも、スポット径が大きく、エネルギー密度が小さい前記＜１＞に記載のプリント配線板の製造方法である。
＜３＞　第１のレーザ光によるマスキングフィルムの開口部の直径は、絶縁層の一方の側の回路配線の開口部の直径よりも大きい前記＜１＞から＜２＞のいずれかに記載のプリント配線板の製造方法である。
＜４＞　ビアホールは、第１のレーザ光により形成された開口部を有する絶縁層の一方の側の回路配線をマスクとして、第２のレーザ光により絶縁層を貫通して形成される前記＜１＞から＜３＞のいずれかに記載のプリント配線板の製造方法である。
＜５＞　ビアホールを第２のレーザ光により形成した後、スミアを除去して、前記ビアホール内に導電性ペーストを充填し、乾燥して熱プレスし、各回路配線を電気的に接続する前記＜４＞に記載のプリント配線板の製造方法である。
＜６＞　絶縁層と、前記絶縁層の両面に形成された金属箔による回路配線と、前記絶縁層に設けられたビアホールに充填され、前記絶縁層の両面に形成された各回路配線を電気的に接続する導電性ペーストとを有するプリント配線板において、前記絶縁層の一方の側の回路配線表面にマスキングフィルムを貼り付けた状態で、第１のレーザ光が照射されることにより前記絶縁層の一方の側の回路配線の開口部が形成され、前記第１のレーザ光により前記マスキングフィルムに形成された開口部周縁の隆起部稜線の直径よりも大きなスポット径の第２のレーザ光が、前記絶縁層の一方の側の回路配線の開口部に照射されることにより前記ビアホールが形成され、前記導電性ペーストは、前記第２のレーザ光により形成された前記ビアホール周縁部の、前記マスキングフィルム開口部の内側部分の前記回路配線表面に積層されることを特徴とするプリント配線板である。
＜７＞　絶縁層はポリイミドであり、前記絶縁層の両面に銅箔が貼られた両面銅張り板を有する前記＜６＞に記載のプリント配線板である。 Means for solving the above problems are as follows. That is,
<1> An insulating layer, circuit wiring using metal foil formed on both surfaces of the insulating layer, and vias provided in the insulating layer are electrically connected to the circuit wiring formed on both surfaces of the insulating layer. In the method of manufacturing a printed wiring board having a conductive paste connected to a mask, a masking film is attached to a circuit wiring surface on one side of the insulating layer, and a first laser beam is applied to the surface on which the masking film is attached. The masking film and the circuit wiring on one side of the insulating layer are formed with an opening, and a spot having a spot diameter larger than the diameter of the ridge line of the raised portion formed at the periphery of the opening of the masking film is formed. Forming the via hole in the insulating layer with the laser beam of 2 and filling the via hole with the conductive paste to electrically connect the circuit wirings. This is a method for manufacturing a printed wiring board.
<2> The method for producing a printed wiring board according to <1>, wherein the second laser light has a larger spot diameter and lower energy density than the first laser light.
<3> The print according to any one of <1> to <2>, wherein a diameter of the opening of the masking film by the first laser beam is larger than a diameter of the opening of the circuit wiring on one side of the insulating layer. It is a manufacturing method of a wiring board.
<4> The via hole is formed by penetrating the insulating layer by the second laser light with the circuit wiring on one side of the insulating layer having the opening formed by the first laser light as a mask. > To <3>. The method for producing a printed wiring board according to any one of <3>.
<5> After the via hole is formed by the second laser beam, the smear is removed, the via hole is filled with a conductive paste, dried and hot-pressed, and each circuit wiring is electrically connected. 4>. The method for producing a printed wiring board according to 4>.
<6> An insulating layer, circuit wiring using metal foil formed on both surfaces of the insulating layer, and vias provided in the insulating layer are electrically connected to the circuit wiring formed on both surfaces of the insulating layer. In the printed wiring board having a conductive paste connected to the surface of the insulating layer, the masking film is attached to the surface of the circuit wiring on one side of the insulating layer and irradiated with the first laser light. The second laser beam having a spot diameter larger than the diameter of the ridge line at the periphery of the opening formed in the masking film by the first laser beam is formed on one side of the circuit wiring opening. The via hole is formed by irradiating the opening of the circuit wiring on one side of the insulating layer, and the conductive paste is formed at the periphery of the via hole formed by the second laser beam. The printed wiring board is laminated on the surface of the circuit wiring in an inner portion of the masking film opening.
<7> The printed wiring board according to <6>, wherein the insulating layer is polyimide, and has a double-sided copper-clad board in which copper foil is pasted on both sides of the insulating layer.
　本発明のプリント配線板及びその製造方法によれば、プリント配線板の各層の回路を接続する貫通孔内に導電性ペーストが確実に充填され、導電性ペーストと回路を形成した金属箔との接合面積及び接合強度が高くなる。これにより、導電性ペーストによる層間接続の電気抵抗が低く接続の信頼性も高く、ヒートサイクルや熱衝撃等に対する電気的接続の信頼性も高くなる。そして、電子機器の耐環境性能や耐久性を向上させ、しかも、コストの増加も少なくなる。 According to the printed wiring board and the manufacturing method thereof of the present invention, the conductive paste is surely filled in the through holes connecting the circuits of the respective layers of the printed wiring board, and the conductive paste and the metal foil forming the circuit are joined. Area and bonding strength are increased. Thereby, the electrical resistance of the interlayer connection by the conductive paste is low and the connection reliability is high, and the reliability of the electrical connection against heat cycle, thermal shock and the like is also high. And the environmental resistance performance and durability of an electronic device are improved, and the increase in cost is also reduced.
図１Ａは、本発明の一実施形態のプリント配線板の製造工程を示した概略断面図である（その１）。FIG. 1A is a schematic cross-sectional view illustrating a manufacturing process of a printed wiring board according to an embodiment of the present invention (part 1). 図１Ｂは、本発明の一実施形態のプリント配線板の製造工程を示した概略断面図である（その２）。FIG. 1: B is schematic sectional drawing which showed the manufacturing process of the printed wiring board of one Embodiment of this invention (the 2). 図１Ｃは、本発明の一実施形態のプリント配線板の製造工程を示した概略断面図である（その３）。FIG. 1: C is schematic sectional drawing which showed the manufacturing process of the printed wiring board of one Embodiment of this invention (the 3). 図１Ｄは、本発明の一実施形態のプリント配線板の製造工程を示した概略断面図である（その４）。FIG. 1D is a schematic cross-sectional view showing the manufacturing process of the printed wiring board according to the embodiment of the present invention (No. 4). 図２Ａは、本発明の一実施形態のプリント配線板の図１の製造工程に続く製造工程を示した概略断面図である（その１）。FIG. 2A is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (No. 1). 図２Ｂは、本発明の一実施形態のプリント配線板の図１の製造工程に続く製造工程を示した概略断面図である（その２）。FIG. 2B is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (part 2). 図２Ｃは、本発明の一実施形態のプリント配線板の図１の製造工程に続く製造工程を示した概略断面図である（その３）。FIG. 2C is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (No. 3). 図２Ｄは、本発明の一実施形態のプリント配線板の図１の製造工程に続く製造工程を示した概略断面図である（その４）。FIG. 2D is a schematic cross-sectional view showing a manufacturing process subsequent to the manufacturing process of FIG. 1 of the printed wiring board according to the embodiment of the present invention (No. 4). 図３Ａは、従来のプリント配線板の製造工程を示した概略断面図である（その１）。FIG. 3A is a schematic cross-sectional view showing a manufacturing process of a conventional printed wiring board (No. 1). 図３Ｂは、従来のプリント配線板の製造工程を示した概略断面図である（その２）。FIG. 3: B is schematic sectional drawing which showed the manufacturing process of the conventional printed wiring board (the 2). 図３Ｃは、従来のプリント配線板の製造工程を示した概略断面図である（その３）。FIG. 3: C is schematic sectional drawing which showed the manufacturing process of the conventional printed wiring board (the 3). 図３Ｄは、従来のプリント配線板の製造工程を示した概略断面図である（その４）。FIG. 3D is a schematic cross-sectional view showing the manufacturing process of the conventional printed wiring board (No. 4). 図３Ｅは、従来のプリント配線板の製造工程を示した概略断面図である（その５）。FIG. 3E is a schematic cross-sectional view showing the manufacturing process of the conventional printed wiring board (No. 5). 図４は、本発明の比較例のプリント配線板の製造方法を示した概略断面図である。FIG. 4 is a schematic cross-sectional view showing a method for manufacturing a printed wiring board of a comparative example of the present invention.
（プリント配線板の製造方法）
　本発明のプリント配線板の製造方法は、少なくともマスキングフィルム貼り付け工程と、開口部形成工程と、ビアホール形成工程と、導電性ペースト充填工程とを含み、さらに、必要に応じて適宜選択した、その他の工程を含む。 (Printed wiring board manufacturing method)
The method for producing a printed wiring board of the present invention includes at least a masking film attaching step, an opening forming step, a via hole forming step, and a conductive paste filling step, and further appropriately selected as necessary. These steps are included.
＜マスキングフィルム貼り付け工程＞
　前記マスキングフィルム貼り付け工程は、絶縁層の一方の側の回路配線表面にマスキングフィルムを貼り付ける工程である。
―マスキングフィルム―
　前記マスキングフィルムとしては、特に制限はなく、目的に応じて適宜選択することができ、例えば、ＰＥＴフィルムに粘着剤が塗布されたもの、などが挙げられる。
　前記マスクフィルムのラミネート方法としては、特に制限はなく、目的に応じて適宜選択することができ、例えば、真空ラミネート法、などが挙げられる。
　また、前記マスキングフィルムは、回路が未形成の銅箔に直接貼り付けられるので、表面が均一で凹凸や段差がなく、容易に良好に貼り付け可能である。
―絶縁層―
　前記絶縁層の材質としては、絶縁性を有する限り、特に制限はなく、目的に応じて適宜選択することができるが、例えば、ポリイミドが好ましい。
　前記絶縁層の厚みとしては、特に制限はなく、目的に応じて適宜選択することができる。
―回路配線―
　前記回路配線としては、特に制限はなく、目的に応じて適宜選択することができ、例えば、金属箔が挙げられ、中でも、銅箔が好ましい。 <Masking film application process>
The masking film attaching step is a step of attaching a masking film to the circuit wiring surface on one side of the insulating layer.
―Masking film―
There is no restriction | limiting in particular as said masking film, According to the objective, it can select suitably, For example, what applied the adhesive to PET film etc. are mentioned.
There is no restriction | limiting in particular as a lamination method of the said mask film, According to the objective, it can select suitably, For example, a vacuum lamination method etc. are mentioned.
Further, since the masking film is directly affixed to a copper foil with no circuit formed thereon, it can be easily and satisfactorily affixed with a uniform surface and no irregularities or steps.
―Insulating layer―
The material of the insulating layer is not particularly limited as long as it has insulating properties, and can be appropriately selected according to the purpose. For example, polyimide is preferable.
There is no restriction | limiting in particular as thickness of the said insulating layer, According to the objective, it can select suitably.
―Circuit wiring―
There is no restriction | limiting in particular as said circuit wiring, According to the objective, it can select suitably, For example, metal foil is mentioned, Especially, copper foil is preferable.
＜開口部形成工程＞
　前記開口部形成工程は、マスキングフィルムが貼り付けられた面に第１のレーザ光を照射して、前記マスキングフィルム及び絶縁層の一方の側の回路配線に開口部を形成する工程である。
―第１のレーザ光―
　前記第１のレーザ光としては、特に制限はなく、目的に応じて適宜選択することができるが、例えば、エキシマレーザ等のＵＶレーザ光が好ましい。 <Opening step>
The opening forming step is a step of forming an opening in the circuit wiring on one side of the masking film and the insulating layer by irradiating the surface on which the masking film is attached with a first laser beam.
-First laser beam-
There is no restriction | limiting in particular as said 1st laser beam, Although it can select suitably according to the objective, For example, UV laser beams, such as an excimer laser, are preferable.
＜ビアホール形成工程＞
　前記ビアホール形成工程は、マスキングフィルムの開口部周縁に形成された隆起部の稜線の直径よりも大きなスポット径の第２のレーザ光により、前記絶縁層に前記ビアホールを形成する工程である。
―第２のレーザ光―
　前記第２のレーザ光としては、特に制限はなく、目的に応じて適宜選択することができ、例えば、ＣＯ２レーザ光、ＹＡＧレーザ、などが挙げられる。なお、第２のレーザは、第１のレーザよりエネルギー密度が小さいことが好ましい。
―開口部周縁に形成された隆起部の稜線―
　隆起部は、マスキングフィルムの開口部周縁部に、盛り上がった環状である。
　前記隆起部の稜線とは、隆起部の頂点を結んだ線である。
　前記稜線の直径の測定方法としては、特に制限はなく、目的に応じて適宜選択することができ、例えば、顕微鏡を使用した断面観察、表面観察による測定方法、などが挙げられる。 <Via hole formation process>
The via hole forming step is a step of forming the via hole in the insulating layer with a second laser beam having a spot diameter larger than the diameter of the ridge line of the raised portion formed at the periphery of the opening of the masking film.
-Second laser beam-
As the second laser beam is not particularly limited and may be appropriately selected depending on the purpose, for example, CO 2 laser, YAG lasers and the like. Note that the second laser preferably has a lower energy density than the first laser.
―Ridge of the ridge formed on the periphery of the opening―
The raised portion has a ring shape that rises at the periphery of the opening of the masking film.
The ridge line of the raised portion is a line connecting the vertices of the raised portion.
There is no restriction | limiting in particular as a measuring method of the diameter of the said ridgeline, According to the objective, it can select suitably, For example, the cross-sectional observation using a microscope, the measuring method by surface observation, etc. are mentioned.
＜導電性ペースト充填工程＞
　前記導電性ペースト充填工程は、ビアホールに導電性ペーストを充填して各回路配線を電気的に接続する工程である。
―導電性ペースト―
　前記導電性ペーストは、熱可塑性樹脂中に高融点金属と低融点金属の金属粒子が混合され、後の加熱処理で合金化するものである限り、特に制限はなく、目的に応じて適宜選択することができる。
　前記高融点金属としては、特に制限はなく、目的に応じて適宜選択することができ、例えば、少なくとも銅を含む粒子（銅単体の粒子、金、銀、亜鉛、及びニッケルの内１つ以上の金属と銅とを含む合金の粒子）、などが挙げられる。また、前記金属粒子の表面は、金、銀、亜鉛、又はニッケル、又はそれらの合金がメッキ等により被覆されていてもよい。前記金属粒子の平均粒径としては、特に制限はなく、目的に応じて適宜選択することができるが、約１μｍ～約１０μｍ（例えば、６μｍ）が好ましい。
　前記低融点金属としては、特に制限はなく、目的に応じて適宜選択することができ、例えば、Ｓｎ、又はＳｎを含む合金（例えば、ハンダ）の粒子、などが挙げられる。
　前記ハンダとしては、特に制限はなく、目的に応じて適宜選択することができ、例えば、Ｓｎ－Ｃｕ系ハンダ、Ｓｎ－Ａｇ系ハンダ、Ｓｎ－Ａｇ－Ｃｕ系ハンダ、これらにＩｎ、Ｚｎ、Ｂｉのいずれか一つ以上を添加し、さらに適宜混合したもの、などが挙げられる。
　前記導電性ペーストのバインダ樹脂としては、熱可塑性樹脂である限り、特に制限はなく、目的に応じて適宜選択することができ、例えば、ポリエステル、ポリオレフィン、ポリアミド、ポリアミドイミド、ポリエーテルイミド、ポリフェニレンエーテル、ポリフェニレンスルフィド、ポリビニルブチラールなどの樹脂、その他、エポキシ樹脂、アクリル樹脂、などが挙げられる。
―導電性ペーストの充填方法―
　前記導電性ペーストの充填方法としては、特に制限はなく、目的に応じて適宜選択することができるが、例えば、スクリーン印刷、インクジェット印刷等の印刷、などの方法が挙げられる。また、剥離性のフィルムをマスク材として、ビアホールにスクイーズにより充填する方法も用いることができる。 <Conductive paste filling process>
The conductive paste filling step is a step of filling the via holes with the conductive paste and electrically connecting the circuit wirings.
―Conductive paste―
The conductive paste is not particularly limited and may be appropriately selected depending on the purpose as long as the metal particles of the high melting point metal and the low melting point metal are mixed in the thermoplastic resin and alloyed by the subsequent heat treatment. be able to.
The refractory metal is not particularly limited and may be appropriately selected depending on the purpose. For example, particles containing at least copper (one or more particles of copper, gold, silver, zinc, and nickel) Alloy particles containing metal and copper), and the like. The surface of the metal particles may be coated with gold, silver, zinc, nickel, or an alloy thereof by plating or the like. The average particle diameter of the metal particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably about 1 μm to about 10 μm (for example, 6 μm).
There is no restriction | limiting in particular as said low melting metal, According to the objective, it can select suitably, For example, the particle | grains of Sn (for example, solder) containing Sn, etc. are mentioned.
The solder is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include Sn—Cu solder, Sn—Ag solder, Sn—Ag—Cu solder, In, Zn, Bi Any one or more of these may be added and further mixed as appropriate.
The binder resin of the conductive paste is not particularly limited as long as it is a thermoplastic resin, and can be appropriately selected according to the purpose. For example, polyester, polyolefin, polyamide, polyamideimide, polyetherimide, polyphenylene ether , Resins such as polyphenylene sulfide and polyvinyl butyral, etc., and other resins such as epoxy resins and acrylic resins.
-Filling method of conductive paste-
There is no restriction | limiting in particular as the filling method of the said electrically conductive paste, Although it can select suitably according to the objective, For example, methods, such as printing, such as screen printing and inkjet printing, are mentioned. Moreover, the method of filling a via hole with a squeeze can be used by using a peelable film as a mask material.
　以下、本発明のプリント配線板の一実施形態について、図１及び図２を基にして説明する。この実施形態のプリント配線板１０は、絶縁層１２の両面に、金属箔である銅箔１３，１４から成る回路配線１３ａ，１４ａが形成されている。絶縁層１２は、ポリイミド等の絶縁性の基板から成り、両面に銅箔１３，１４が貼り付けられたものである。絶縁層１２の表裏面の銅箔１３，１４は、後述する工程を経て、所定の回路パターンに形成され、回路配線１３ａ，１４ａを構成している。 Hereinafter, an embodiment of the printed wiring board of the present invention will be described with reference to FIGS. 1 and 2. In the printed wiring board 10 of this embodiment, circuit wirings 13 a and 14 a made of copper foils 13 and 14 that are metal foils are formed on both surfaces of an insulating layer 12. The insulating layer 12 is made of an insulating substrate such as polyimide, and has copper foils 13 and 14 attached to both sides. The copper foils 13 and 14 on the front and back surfaces of the insulating layer 12 are formed in a predetermined circuit pattern through the steps described later, and constitute circuit wirings 13a and 14a.
　絶縁層１２には、表裏の回路配線１３ａ，１４ａ間を電気的に接続するためのビアホール１６が形成され、導電性ペースト１８による層間接続部材により、表裏の回路配線１３ａ，１４ａが接続されている。 Via holes 16 are formed in the insulating layer 12 to electrically connect the circuit wirings 13a and 14a on the front and back sides, and the circuit wirings 13a and 14a on the front and back sides are connected by an interlayer connection member made of a conductive paste 18. .
　次に、この実施形態のプリント配線板１０製造方法について、図１及び図２を基にして説明する。先ず、図１Ａに示すように、ポリイミド等を基板とした両面銅張り板２２の銅箔１３が形成された一側面側にマスキングフィルム２４を貼り付ける。 Next, a method for manufacturing the printed wiring board 10 of this embodiment will be described with reference to FIGS. First, as shown to FIG. 1A, the masking film 24 is affixed on the one side surface in which the copper foil 13 of the double-sided copper-clad board 22 which used polyimide etc. as the board | substrate was formed.
　次に、両面銅張り板２２に、マスキングフィルム２４側からエキシマレーザ等のＵＶレーザ光Ｌ１を照射し、マスキングフィルム２４に開口２６を形成するとともに、同時に銅箔１３にも開口部２８を形成する（図１Ｂ）。このとき、マスキングフィルム２４の開口部２６周縁部には、盛り上がった環状の隆起部２６ａが形成される。このレーザ加工は、カッパーダイレクト法と言われる、公知の方法である。この隆起部２６ａの稜線により形成される円の直径Ｄ１は、銅箔１３の開口部２８の直径Ｄ２よりも大きい。即ち、常にＤ１＞Ｄ２の関係にある。さらに、レーザ光Ｌ１によるマスキングフィルム２４の開口部２６の直径Ｄ０は、銅箔１３の開口部２８の直径Ｄ２よりも大きい。即ち、Ｄ０＞Ｄ２の関係にあり、常にＤ１＞Ｄ０＞Ｄ２の関係が成り立つ。 Next, the double-sided copper-clad plate 22 is irradiated with UV laser light L1 such as an excimer laser from the masking film 24 side to form an opening 26 in the masking film 24 and simultaneously form an opening 28 in the copper foil 13. (FIG. 1B). At this time, a raised annular ridge 26 a is formed on the periphery of the opening 26 of the masking film 24. This laser processing is a known method called a copper direct method. The diameter D1 of the circle formed by the ridge line of the raised portion 26a is larger than the diameter D2 of the opening 28 of the copper foil 13. That is, there is always a relationship of D1> D2. Further, the diameter D0 of the opening 26 of the masking film 24 by the laser light L1 is larger than the diameter D2 of the opening 28 of the copper foil 13. That is, there is a relationship of D0> D2, and a relationship of D1> D0> D2 is always established.
　次に、絶縁層１２にビアホール１６を形成する。ビアホール１６の形成も、ＣＯ２レーザ光やＹＡＧレーザ等のレーザ光Ｌ２により行う。このときのレーザ光Ｌ２のスポット径Ｄ３は、マスキングフィルム２４の隆起部２６ａの稜線の直径Ｄ１よりも大きい（図１Ｃ）。即ち、Ｄ３＞Ｄ１の関係にある。これにより、図１Ｄに示すように、マスキングフィルム２４の開口部２６周縁の隆起部２６ａの大部分がレーザ光Ｌ２により除去されて、隆起部２６ａの高さが低くなり、略平坦化するとともに、直径Ｄ３の拡張した開口部２７の内側に、銅箔１３の開口部２８の周縁部２８ａが露出する。これとともに、ビアホール１６が銅箔１３の開口部２８によりマスキングされてその直径Ｄ２の開口で形成される。このとき、裏面側の銅箔１４は貫通させない程度のレーザ光Ｌ２の出力に調整されている。従って、レーザ光Ｌ２は、スッポット径がＵＶレーザ光Ｌ１よりも大きく、エネルギー密度、即ち光の強度はＵＶレーザ光Ｌ１よりも小さいものである。 Next, a via hole 16 is formed in the insulating layer 12. The via hole 16 is also formed by a laser beam L2 such as a CO 2 laser beam or a YAG laser. The spot diameter D3 of the laser beam L2 at this time is larger than the diameter D1 of the ridge line of the raised portion 26a of the masking film 24 (FIG. 1C). That is, there is a relationship of D3> D1. As a result, as shown in FIG. 1D, most of the raised portions 26a around the periphery of the opening 26 of the masking film 24 are removed by the laser light L2, and the height of the raised portions 26a is reduced and substantially flattened. The peripheral edge portion 28a of the opening portion 28 of the copper foil 13 is exposed inside the opening portion 27 having an expanded diameter D3. At the same time, the via hole 16 is masked by the opening 28 of the copper foil 13 and formed with an opening having a diameter D2. At this time, the output of the laser beam L2 is adjusted so as not to penetrate the copper foil 14 on the back surface side. Therefore, the laser beam L2 has a spot diameter larger than that of the UV laser beam L1, and the energy density, that is, the intensity of the light is smaller than that of the UV laser beam L1.
　この後、ビアホール１６内をデスミア処理し、図２Ａに示すように、導電性ペースト１８をビアホール１６内に充填する。 Thereafter, the inside of the via hole 16 is desmeared, and the conductive paste 18 is filled into the via hole 16 as shown in FIG. 2A.
　次に、図２Ｂに示すように、マスキングフィルム２４を剥離し、両面銅張り板２２を熱プレスして導電性ペースト１８を溶融・硬化させて、銅箔１３，１４間の電気的接続を図る。その後、回路配線１３ａ，１４ａを形成する表裏面の銅箔１３，１４に、エッチングレジストのドライフィルム３０を貼り付け（図２Ｃ）、所定の回路パターンに露光してエッチングし、図２Ｄに示すように、回路配線１３ａ，１４ａを形成する。以上の工程を経て、両面銅張り板２２の両面の回路配線１３ａ，１４ａが層間接続されたプリント配線板１０が形成される。 Next, as shown in FIG. 2B, the masking film 24 is peeled off, and the double-sided copper-clad plate 22 is hot-pressed to melt and cure the conductive paste 18 to achieve electrical connection between the copper foils 13 and 14. . Thereafter, a dry film 30 of an etching resist is attached to the copper foils 13 and 14 on the front and back surfaces forming the circuit wirings 13a and 14a (FIG. 2C), exposed to a predetermined circuit pattern and etched, as shown in FIG. 2D. Then, circuit wirings 13a and 14a are formed. Through the above steps, the printed wiring board 10 in which the circuit wirings 13a and 14a on both sides of the double-sided copper-clad board 22 are interlayer-connected is formed.
　この実施形態のプリント配線板１０によれば、導電性ペースト１８による層間接続部材が、ビアホール１６の周縁に位置した銅箔１３の開口部２８の周縁部２８ａにも付着し、確実で抵抗の小さい層間接続が可能となる。また、この実施形態のプリント配線板１０の製造方法によれば、簡単な工程で、小径のビアホール１６を形成することができ、ビアホール１６内への導電性ペースト１８の充填も確実に行うことができる。これは、分散された金属粒子の２次凝集粒子が、マスキングフィルム２４の拡張した開口部２７により充填が妨げられないので、充分な量の導電性ペースト１８がビアホール１６内に充填されるからであると考えられる。これにより、層間接続部の電気的接続が確実で強度も高くなり、ヒートサイクルや熱衝撃等に対する電気的接続の信頼性が向上し、使用する電子機器の耐環境性能や耐久性を向上させ、しかも、コストの増加も少ないものである。 According to the printed wiring board 10 of this embodiment, the interlayer connection member made of the conductive paste 18 also adheres to the peripheral portion 28a of the opening 28 of the copper foil 13 located at the peripheral edge of the via hole 16, and is reliable and has low resistance. Interlayer connection is possible. Further, according to the method of manufacturing the printed wiring board 10 of this embodiment, the small-diameter via hole 16 can be formed by a simple process, and the conductive paste 18 can be reliably filled into the via hole 16. it can. This is because the secondary agglomerated particles of the dispersed metal particles are not prevented from being filled by the expanded openings 27 of the masking film 24, so that a sufficient amount of the conductive paste 18 is filled in the via holes 16. It is believed that there is. As a result, the electrical connection of the interlayer connection part is reliable and high in strength, the reliability of the electrical connection against heat cycle, thermal shock, etc. is improved, the environmental resistance performance and durability of the electronic device to be used are improved, Moreover, the increase in cost is small.
　また、本願発明の作用効果を発揮するには、上述のＤ３＞Ｄ１の関係が必須である。例えば、図４に示すように、マスキングフィルム２４の開口部２６の直径Ｄ０が銅箔１３の開口部２８の直径Ｄ２よりも大きく（Ｄ０＞Ｄ２）、レーザ光Ｌ２のスポット径Ｄ３が直径Ｄ２よりも大きくても（Ｄ３＞Ｄ２）、マスキングフィルム２４の隆起部２６ａの稜線の直径Ｄ１よりもレーザ光Ｌ２のスポット径Ｄ３が小さい場合（Ｄ１＞Ｄ３）、上述の作用効果は発揮しない。これは、レーザ光Ｌ２の照射によっても隆起部２６ａが残り、導電性ペースト１８が銅箔１３の開口部２８の周囲に十分に接触できないからである。 Further, in order to exert the effects of the present invention, the above relationship D3> D1 is essential. For example, as shown in FIG. 4, the diameter D0 of the opening 26 of the masking film 24 is larger than the diameter D2 of the opening 28 of the copper foil 13 (D0> D2), and the spot diameter D3 of the laser light L2 is larger than the diameter D2. Is larger (D3> D2), when the spot diameter D3 of the laser beam L2 is smaller than the diameter D1 of the ridge line of the raised portion 26a of the masking film 24 (D1> D3), the above-described effects are not exhibited. This is because the raised portion 26 a remains even by irradiation with the laser beam L 2, and the conductive paste 18 cannot sufficiently contact the periphery of the opening 28 of the copper foil 13.
　なお、この発明のプリント配線板とその製造方法は、上記実施形態に限定されるものではなく、ビアホールに充填される導電性ペーストの種類は適宜選択可能であり、このプリント配線板に積層される配線板の層数も適宜設定可能なものである。また、絶縁層の厚みや材質も適宜設定可能なものであり、レーザ光の種類や照射径、照射方法も適宜設定可能なものである。 The printed wiring board and the manufacturing method thereof according to the present invention are not limited to the above embodiment, and the type of conductive paste filled in the via hole can be selected as appropriate, and is laminated on the printed wiring board. The number of layers of the wiring board can also be set as appropriate. Further, the thickness and material of the insulating layer can be set as appropriate, and the type, irradiation diameter, and irradiation method of the laser light can also be set as appropriate.
　次に、本発明のプリント配線板及びその製造方法の一実施例について以下に説明する。実施例１では、両面銅張りポリイミド基板の一方の面にＰＥＴ製のマスキングフィルムを貼り付けた。そして、マスキングフィルム側の面から、ＵＶレーザ光を用いて、カッパーダイレクト法により、マスキングフィルム及び銅箔に開口部を形成した。このときの開口部の環状の稜線の直径Ｄ１は、Ｄ１＝９７μｍであった。この直径Ｄ１の値は、両面銅張り板に形成した４万個の開口部から５個の開口部を選択して平均値を求めた値である。また、銅箔に形成された開口部の直径Ｄ２は、Ｄ２＝５０μｍであった。 Next, an example of the printed wiring board and the manufacturing method thereof according to the present invention will be described below. In Example 1, a PET masking film was attached to one surface of a double-sided copper-clad polyimide substrate. And the opening part was formed in the masking film and copper foil by the copper direct method from the surface by the side of a masking film using UV laser beam. The diameter D1 of the annular ridge line of the opening at this time was D1 = 97 μm. The value of the diameter D1 is a value obtained by selecting five openings from the 40,000 openings formed on the double-sided copper-clad plate and calculating an average value. The diameter D2 of the opening formed in the copper foil was D2 = 50 μm.
　次に、ＹＡＧレーザにより、ポリイミド基板にビアホールを形成した。このときのレーザ光のスポット径は、マスキングフィルムの開口部の稜線を囲むように、稜線の直径Ｄ１よりも大きい直径Ｄ３で、Ｄ３＝１００μｍのスポット径である。ポリイミド基板にビアホールを形成した後、デスミア処理を行い、導電性ペーストを充填し、乾燥させ、マスキングフィルムを剥離し、熱プレスを行った。そして、熱プレスにより、導電性ペーストを硬化させるとともに、ビアホール内に導電性ペーストを圧縮し、その後、銅箔のパターンニングを行った。実施例１では、抵抗値の測定用に、デイジーチェーンのパターンニングを行った。 Next, via holes were formed in the polyimide substrate with a YAG laser. The spot diameter of the laser beam at this time is a diameter D3 larger than the diameter D1 of the ridge line so as to surround the ridge line of the opening of the masking film, and is a spot diameter of D3 = 100 μm. After forming a via hole in the polyimide substrate, desmear treatment was performed, the conductive paste was filled, dried, the masking film was peeled off, and hot pressing was performed. Then, the conductive paste was cured by hot pressing, and the conductive paste was compressed in the via hole, and then the copper foil was patterned. In Example 1, daisy chain patterning was performed for resistance measurement.
比較例１Comparative Example 1
　また、比較例１として、マスキングフィルムにＵＶレーザ光により、開口部の稜線の直径が９７μｍの開口部を形成し、銅箔にも開口部を形成した。このときの銅箔に形成された開口部の直径Ｄ２も、Ｄ２＝５０μｍであった。この後、マスキングフィルムの開口部内にスポット径が６０μｍのレーザ光で、ポリイミド基板にビアホールを形成した。この後は、上記と同様の工程を経て、マスキングフィルムを剥がし、導電性ペーストの充填、パターンニング等を行った。 As Comparative Example 1, an opening having a diameter of the edge of the opening of 97 μm was formed on the masking film by UV laser light, and an opening was also formed on the copper foil. The diameter D2 of the opening formed in the copper foil at this time was also D2 = 50 μm. Thereafter, a via hole was formed in the polyimide substrate with a laser beam having a spot diameter of 60 μm in the opening of the masking film. Thereafter, the masking film was peeled off through the same process as described above, and the conductive paste was filled and patterned.
　この結果、実施例１では、ビアホール１個あたりの抵抗値の平均は、７．５ｍΩであったのに対して、比較例１では、８．１ｍΩであった。また、４万個のビアホールの抵抗値のばらつき（分散σ）は、実施例１ではσ＝１．２ｍΩであったのに対して、比較例１の場合、σ＝２．４ｍΩであった。また、実施例１のプリント配線板は、熱サイクル試験においても不具合が発生することはなかった。 As a result, in Example 1, the average resistance value per via hole was 7.5 mΩ, whereas in Comparative Example 1, it was 8.1 mΩ. Further, the variation in resistance value (dispersion σ) of 40,000 via holes was σ = 1.2 mΩ in Example 1, whereas in Comparative Example 1, σ = 2.4 mΩ. Moreover, the printed wiring board of Example 1 did not have any problems in the thermal cycle test.
　従って、本願発明の実施例１の方が、抵抗値が低く、抵抗値のばらつきも少ないことが確認された。 Therefore, it was confirmed that Example 1 of the present invention had a lower resistance value and less variation in resistance value.
１０　プリント配線板
１２　絶縁層
１３，１４　銅箔
１３ａ，１４ａ　回路配線
１６　ビアホール
１８　導電性ペースト
２２　両面銅張り板
２４　マスキングフィルム
２６，２７，２８　開口部
２６ａ　隆起部 DESCRIPTION OF SYMBOLS 10 Printed wiring board 12 Insulation layer 13, 14 Copper foil 13a, 14a Circuit wiring 16 Via hole 18 Conductive paste 22 Double-sided copper-clad board 24 Masking film 26, 27, 28 Opening 26a Raised part

Claims (7)

  1. 　絶縁層と、前記絶縁層の両面に形成された金属箔による回路配線と、前記絶縁層に設けられたビアホールに充填され、前記絶縁層の両面に形成された各回路配線を電気的に接続する導電性ペーストとを有するプリント配線板の製造方法において、
    　前記絶縁層の一方の側の回路配線表面にマスキングフィルムを貼り付け、
    　前記マスキングフィルムが貼り付けられた面に第１のレーザ光を照射して、前記マスキングフィルム及び前記絶縁層の一方の側の回路配線に開口部を形成し、
    　前記マスキングフィルムの開口部周縁に形成された隆起部の稜線の直径よりも大きなスポット径の第２のレーザ光により、前記絶縁層に前記ビアホールを形成し、
    　前記ビアホールに前記導電性ペーストを充填して前記各回路配線を電気的に接続することを含むことを特徴とするプリント配線板の製造方法。     An insulating layer, circuit wiring using metal foil formed on both surfaces of the insulating layer, and via holes provided in the insulating layer are electrically connected to each circuit wiring formed on both surfaces of the insulating layer. In a method for producing a printed wiring board having a conductive paste,
    Affixing a masking film on the circuit wiring surface on one side of the insulating layer,
    Irradiating the surface on which the masking film is pasted with a first laser beam to form an opening in the circuit wiring on one side of the masking film and the insulating layer,
    The via hole is formed in the insulating layer by a second laser beam having a spot diameter larger than the diameter of the ridge line of the raised portion formed on the periphery of the opening of the masking film,
    A method of manufacturing a printed wiring board, comprising filling the via hole with the conductive paste to electrically connect the circuit wirings.
  2. 　第２のレーザ光は、第１のレーザ光よりも、スポット径が大きく、エネルギー密度が小さい請求項１記載のプリント配線板の製造方法。 The method for manufacturing a printed wiring board according to claim 1, wherein the second laser beam has a larger spot diameter and lower energy density than the first laser beam.
  3. 　第１のレーザ光によるマスキングフィルムの開口部の直径は、絶縁層の一方の側の回路配線の開口部の直径よりも大きい請求項１から２のいずれかに記載のプリント配線板の製造方法。 3. The printed wiring board manufacturing method according to claim 1, wherein the diameter of the opening of the masking film by the first laser beam is larger than the diameter of the opening of the circuit wiring on one side of the insulating layer.
  4. 　ビアホールは、第１のレーザ光により形成された開口部を有する絶縁層の一方の側の回路配線をマスクとして、第２のレーザ光により絶縁層を貫通して形成される請求項１から３のいずれかに記載のプリント配線板の製造方法。 The via hole is formed by penetrating the insulating layer by the second laser beam using the circuit wiring on one side of the insulating layer having the opening formed by the first laser beam as a mask. The manufacturing method of the printed wiring board in any one.
  5. 　ビアホールを第２のレーザ光により形成した後、スミアを除去して、前記ビアホール内に導電性ペーストを充填し、乾燥して熱プレスし、各回路配線を電気的に接続する請求項４記載のプリント配線板の製造方法。 5. The circuit according to claim 4, wherein after the via hole is formed by the second laser beam, the smear is removed, the conductive paste is filled in the via hole, dried and hot pressed, and each circuit wiring is electrically connected. Manufacturing method of printed wiring board.
  6. 　絶縁層と、前記絶縁層の両面に形成された金属箔による回路配線と、前記絶縁層に設けられたビアホールに充填され、前記絶縁層の両面に形成された各回路配線を電気的に接続する導電性ペーストとを有するプリント配線板において、
    　前記絶縁層の一方の側の回路配線表面にマスキングフィルムを貼り付けた状態で、第１のレーザ光が照射されることにより前記絶縁層の一方の側の回路配線の開口部が形成され、
    　前記第１のレーザ光により前記マスキングフィルムに形成された開口部周縁の隆起部稜線の直径よりも大きなスポット径の第２のレーザ光が、前記絶縁層の一方の側の回路配線の開口部に照射されることにより前記ビアホールが形成され、
    　前記導電性ペーストは、前記第２のレーザ光により形成された前記ビアホール周縁部の、前記マスキングフィルム開口部の内側部分の前記回路配線表面に積層されることを特徴とするプリント配線板。     An insulating layer, circuit wiring using metal foil formed on both surfaces of the insulating layer, and via holes provided in the insulating layer are electrically connected to each circuit wiring formed on both surfaces of the insulating layer. In a printed wiring board having a conductive paste,
    With the masking film attached to the circuit wiring surface on one side of the insulating layer, an opening of the circuit wiring on one side of the insulating layer is formed by irradiation with the first laser beam.
    A second laser beam having a spot diameter larger than the diameter of the ridge line at the periphery of the opening formed in the masking film by the first laser beam is applied to the opening of the circuit wiring on one side of the insulating layer. The via hole is formed by irradiation,
    The printed wiring board, wherein the conductive paste is laminated on the surface of the circuit wiring in an inner portion of the opening portion of the masking film at a peripheral portion of the via hole formed by the second laser beam.
  7. 　絶縁層はポリイミドであり、前記絶縁層の両面に銅箔が貼られた両面銅張り板を有する請求項６記載のプリント配線板。 The printed wiring board according to claim 6, wherein the insulating layer is polyimide and has a double-sided copper-clad board in which copper foil is pasted on both sides of the insulating layer.
PCT/JP2010/060776 2009-06-30 2010-06-24 Printed-wiring board and process for manufacture thereof WO2011001900A1 (en)

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JP2003318546A (en) * 2002-02-22 2003-11-07 Fujikura Ltd Multilayer wiring board, base material for the same and their manufacturing method
JP2006202876A (en) * 2005-01-19 2006-08-03 Sumitomo Heavy Ind Ltd Laser beam machining method
JP2007281336A (en) * 2006-04-11 2007-10-25 Fujikura Ltd Method of manufacturing double sided printed wiring board and multilayer printed wiring board
JP2007317823A (en) * 2006-05-25 2007-12-06 Cmk Corp Printed wiring board and its manufacturing method

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JP2003318546A (en) * 2002-02-22 2003-11-07 Fujikura Ltd Multilayer wiring board, base material for the same and their manufacturing method
JP2006202876A (en) * 2005-01-19 2006-08-03 Sumitomo Heavy Ind Ltd Laser beam machining method
JP2007281336A (en) * 2006-04-11 2007-10-25 Fujikura Ltd Method of manufacturing double sided printed wiring board and multilayer printed wiring board
JP2007317823A (en) * 2006-05-25 2007-12-06 Cmk Corp Printed wiring board and its manufacturing method

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