JP2016134424A - Method of manufacturing multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer wiring board, capable of alleviating the occurrence of warps even when the number of laminated layers of wiring layers and insulation layers increases.SOLUTION: In a method of manufacturing a multilayer wiring board, (1) a thin substrate having a thickness of 50 μm or less is adhered to a thick substrate having a thickness of 0.5 mm or more, (2) a conductive paste containing a conductive material is coated by printing, a pattern is formed to the conductive paste having been coated by printing, and thereby a wiring layer comprising a conductor pattern is formed, (3) an insulating paste containing an insulating material is coated on the wiring layer by printing to form an insulation layer, (4) the steps (2) and (3) are repeated a plurality of times, and (5) the thick substrate is peeled off from the thin substrate to obtain a multilayer wiring board including a plurality of the wiring layers and the insulation layers on the thin substrate.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing a multilayer wiring board.

  As multilayer wiring boards used in various electrical devices, electronic components such as coil components, chip inductors, capacitors, multilayer LC filters, functional modules such as VCO (Voltage Controlled Oscillator), PLL (Phase Locked Loop), and the like And ceramic multilayer substrates.

  As a method for manufacturing this multilayer wiring board, for example, an alumina substrate is prepared, and a conductive paste is printed and applied thereon, a pattern is formed to form a wiring layer, and a glass paste is further printed and applied to form an insulating layer. There is a manufacturing method in which the formation of the wiring layer and the insulating layer is repeated a plurality of times, followed by firing to obtain a multilayer wiring board (see, for example, Patent Documents 1 and 3).

  In recent years, these multilayer wiring boards have been required to be further multilayered for miniaturization and high functionality.

Japanese Patent Laid-Open No. 11-120823 JP-A-4-305996 JP 2001-264965 A

  However, when an inductor is manufactured as a multilayer wiring board by the above method, for example, if the number of layers is increased for the purpose of obtaining a high inductance value, the total thickness of the insulating layer becomes thicker. For this reason, if it is going to suppress the thickness of the whole multilayer wiring board, it is necessary to make the thickness of the alumina substrate thinner. If the thickness of the alumina substrate is 50 μm or less in order to suppress the total thickness, the overall warpage including the wiring layer and the insulating layer after drying increases as the number of laminations increases, making lamination difficult.

  An object of the present invention is to provide a method for manufacturing a multilayer wiring board capable of suppressing warpage even when the number of wiring layers and insulating layers is increased.

The manufacturing method of a multilayer wiring board according to the present invention is as follows: (1) A thin substrate with a thickness of 50 μm or less is attached to a thick substrate with a thickness of 0.5 mm or more with an adhesive;
(2) A conductive paste containing a conductive material is printed and applied, and a pattern is formed on the printed conductive paste to form a wiring layer made of a conductor pattern;
(3) An insulating paste containing an insulating material is printed on the wiring layer to form an insulating layer;
(4) The above steps (2) and (3) are repeated a plurality of times,
(5) The thick substrate is peeled from the thin substrate to obtain a multilayer wiring substrate having a plurality of the wiring layers and the insulating layers on the thin substrate.

  According to the method for manufacturing a multilayer wiring board according to the present invention, even if the number of insulating layers / wiring layers stacked on the thin substrate is increased by adhering the thick substrate to the thin substrate. Further, the layers can be stacked without warping.

In the manufacturing method of the multilayer wiring board concerning Embodiment 1, it is a schematic sectional view showing the state where the thin board was stuck on the thick board. In the manufacturing method of the multilayer wiring board concerning Embodiment 1, it is a schematic sectional view showing the state where the 1st wiring layer which consists of a conductive pattern was formed on the thin board. FIG. 3 is a schematic cross-sectional view showing a state in which a first insulating layer is formed on a first wiring layer in the method for manufacturing a multilayer wiring board according to the first embodiment. FIG. 5 is a schematic cross-sectional view showing a state in which a second wiring layer and a second insulating layer are formed in the method for manufacturing a multilayer wiring board according to the first embodiment. 5 is a schematic cross-sectional view showing a state in which a sixth wiring layer and a sixth insulating layer are formed in the method for manufacturing a multilayer wiring board according to Embodiment 1. FIG. Schematic cross section showing a configuration of a multilayer wiring board having a plurality of wiring layers and an insulating layer on a thin substrate obtained by peeling the thick substrate from the thin substrate in the method for manufacturing a multilayer wiring board according to Embodiment 1 FIG.

The manufacturing method of the multilayer wiring board which concerns on a 1st aspect attaches the thin board | substrate with a film thickness of 50 micrometers or less to the thick board | substrate with a film thickness of (1) 0.5 mm or more with an adhesive agent,
(2) A conductive paste containing a conductive material is printed and applied, and a pattern is formed on the printed conductive paste to form a wiring layer made of a conductor pattern;
(3) An insulating paste containing an insulating material is printed on the wiring layer to form an insulating layer;
(4) The above steps (2) and (3) are repeated a plurality of times,
(5) The thick substrate is peeled from the thin substrate to obtain a multilayer wiring substrate having a plurality of the wiring layers and the insulating layers on the thin substrate.

The method for manufacturing a multilayer wiring board according to a second aspect is the adhesive according to the first aspect, wherein the adhesive loses its adhesive strength or is lost by heating in the step of attaching the thin board to the thick board in (1). Affixing the thin substrate to the thick substrate,
In the step of peeling the thick substrate from the thin substrate of (5), after drying the laminated wiring layer and the insulating layer, the adhesive is burned out or the adhesive force is lost, The thick substrate may be peeled from the thin substrate.

  In the method for manufacturing a multilayer wiring board according to a third aspect, in the first or second aspect, the insulating paste may be made of a glass paste.

  In the method for manufacturing a multilayer wiring board according to a fourth aspect, in any one of the first to third aspects, the thin substrate and the thick substrate may be an alumina substrate.

A multilayer wiring board according to a fifth aspect includes a thin board having a thickness of 50 μm or less,
A wiring layer comprising a conductor pattern;
An insulating layer provided on the wiring layer and made of an insulating material;
With
A plurality of sets of the wiring layer and the insulating layer are provided on the thin substrate.

  In the multilayer wiring board according to a sixth aspect, in the fifth aspect, the thin substrate may be an alumina substrate.

  In the multilayer wiring board according to a seventh aspect, in the fifth or sixth aspect, the multilayer wiring board may constitute a coil component.

  A method for manufacturing a multilayer wiring board according to an embodiment will be described below with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.

(Embodiment 1)
<Manufacturing method of multilayer wiring board>
The method for manufacturing a multilayer wiring board according to the first embodiment includes the following steps.
(1) A thin substrate 2 having a thickness of 50 μm or less is attached to a thick substrate 1 having a thickness of 0.5 mm or more with an adhesive (FIG. 1).
(2) A conductive paste containing a conductive material is printed and applied, and a pattern is formed on the printed conductive paste to form a wiring layer 3a composed of a conductor pattern (FIG. 2).
(3) An insulating paste containing an insulating material is printed on the wiring layer 3a to form the insulating layer 4a (FIG. 3).
(4) The steps (2) and (3) are repeated a plurality of times to laminate a plurality of wiring layers 3a, 3b, 3c, 3d, 3e, 3f / insulating layers 4a, 4b, 4c, 4d, 4e, 4f. (FIGS. 4 and 5). FIG. 4 is a schematic cross-sectional view showing a state where up to the second wiring layer 3b / insulating layer 4b is formed, and FIG. 5 shows a state where up to the sixth wiring layer 3f / insulating layer 4f is formed. It is a schematic sectional drawing.
(5) The thick substrate 1 is peeled from the thin substrate 2, and a plurality of wiring layers 3a, 3b, 3c, 3d, 3e, 3f and insulating layers 4a, 4b, 4c, 4d, 4e, 4f are formed on the thin substrate 2. A multilayer wiring board 10 having the following is obtained (FIG. 6).

  According to this multilayer wiring board manufacturing method, the thick substrate 1 is bonded to the thin substrate 2 so that the wiring layers 3a, 3b, 3c, 3d, 3e, 3f on the thin substrate 2 are bonded. / Even if the number of the insulating layers 4a, 4b, 4c, 4d, 4e, and 4f increases, the insulating layers 4a, 4b, 4c, 4d, 4e, and 4f can be stacked without increasing warpage during drying. Specifically, the thin substrate 2 can be supported by the thick substrate 1 by attaching the thin substrate 2 having a thickness of 50 μm or less to the thick substrate 1 having a thickness of 0.5 mm or more. As a result, the applied conductive paste and insulating paste can resist shrinkage stress that tends to shrink when drying, and the occurrence of warping during drying can be suppressed. The warp of the thin substrate 2 is preferably 0.5 mm or less as a difference in thickness between the end and the center of the thin substrate 2 having a length of 4 inches (10.16 cm). As a result, the occurrence of cracks or the like when the multilayer wiring board 10 is vacuum chucked can be suppressed.

  Below, each component in the manufacturing method of this multilayer wiring board is demonstrated.

<Thin substrate>
As the thin substrate 2, an insulating substrate having a thickness of 50 μm or less, such as an alumina substrate, a ceramic substrate, or ferrite can be used.

<Thick substrate>
As the thick substrate 1, a substrate having a thickness of 0.5 mm or more, for example, an alumina substrate, a ceramic substrate, or the like can be used. In addition, an alumina substrate, a ceramic substrate, etc. are examples, and it is not limited to this, What consists of arbitrary materials can be used.

<Adhesive>
Any adhesive may be used as long as it can adhere the thick substrate 1 to the thin substrate 2 and is peeled off by heating or loss of adhesion. As this adhesive, for example, a resin such as a thermosetting resin or a thermoplastic resin, or a temporary fixing adhesive (for example, manufactured by Daicel Corporation (see article on March 31, 2014 in Chemical Industry Daily)) Can be used.
As described above, as the adhesive for attaching the thick substrate 1 to the thin substrate 2, the adhesive that peels off by heating (firing) or loses the adhesive force is used, so a plurality of wiring layers / insulating layers are laminated. Then, the thick substrate 1 can be peeled from the thin substrate 2 by heating after drying. Further, when the wiring layer and the insulating layer are fired and the thick substrate 1 is peeled off by heating at the same time, the shrinkage stress is released because the solvent is burned away by the firing of the wiring layer and the insulating layer. Note that the wiring layer and the insulating layer may be fired after the thick substrate 1 is peeled off by heating.
Since the thick substrate 1 is peeled off from the thin substrate 2 by firing, firing cannot be performed for each wiring layer and insulating layer, and it is necessary to fire after all the wiring layers / insulating layers are stacked. .

<Conductive paste>
As a conductive paste containing a conductive material, any conventional paste can be used. As the conductive material, for example, metal powder such as gold, silver, copper, platinum, aluminum, palladium, nickel, molybdenum and tungsten can be used. As the organic solvent, any commonly used organic solvent such as alcohol, toluene, methyl ethyl ketone, acetone, ethyl acetate, vinyl acetate, ethyl carbitol acetate, and dipropylene glycol monomethyl ether can be used. As the conductive paste, for example, a gold paste, a silver paste, an aluminum paste, or the like may be used.

<Insulating paste>
As an insulating paste containing an insulating material, any conventional paste can be used.
Insulating materials include Al ₂ O ₃ , crystallized glass-based, glass composite-based, non-glass-based insulating ceramic powders, dielectric ceramic powders such as BaTiO ₃ , ferrites such as nickel zinc ferrite and nickel zinc copper ferrite A high-resistance ceramic powder such as a composite powder, RuO ₂ , Pb ₂ Ru ₂ O ₇ , Bi ₂ Ru ₂ O ₇ , a composite oxide of Mn · Co · Ni, a piezoelectric ceramic powder such as PZT, or the like can be used. As the organic solvent, any commonly used organic solvent such as alcohol, toluene, methyl ethyl ketone, acetone, ethyl acetate, vinyl acetate, ethyl carbitol acetate, and dipropylene glycol monomethyl ether can be used. As the insulating paste, for example, an alumina paste, a glass paste, or the like may be used.
When the multilayer wiring board 10 is used as a coil component, a low dielectric constant glass paste is preferable as the insulating paste.

<Multilayer wiring board>
FIG. 6 schematically shows a configuration of a multilayer wiring board 10 having a plurality of wiring layers 3a, 3b, 3c, 3d, 3e, and 3f and insulating layers 4a, 4b, 4c, 4d, 4e, and 4f on the thin substrate 2. It is sectional drawing. The multilayer wiring board 10 includes a thin substrate 2 having a thickness of 50 μm or less, wiring layers 3a, 3b, 3c, 3d, 3e, and 3f made of a conductor pattern, and wiring layers 3a, 3b, 3c, 3d, 3e, and 3f. And insulating layers 4a, 4b, 4c, 4d, 4e, and 4f made of an insulating material. On the thin substrate 2, a plurality of sets of wiring layers 3a, 3b, 3c, 3d, 3e, and 3f and insulating layers 4a, 4b, 4c, 4d, 4e, and 4f are provided.
This multilayer wiring board 10 has a thin substrate 2 having a thickness of 50 μm or less, but warps as a difference in thickness between the end and the center of the thin substrate 2 having a length of 4 inches (10.16 cm). It can be 0.5 mm or less. The multilayer wiring board 10 is obtained by the above-described method for manufacturing a multilayer wiring board. The thick substrate 1 is bonded to the thin substrate 2 so that warpage occurs during drying. Because it was able to be suppressed. As seen in the comparative example described later, when the wiring layer and the insulating layer are directly formed on the thin substrate 2 having a thickness of 50 μm or less without using the thick substrate 1, the warp becomes 1 mm or more and becomes multilayered. It becomes difficult. That is, in the multilayer wiring board 10 using the thin substrate 2 having a thickness of 50 μm or less and the thin substrate 2 having a length of 4 inches (10.16 cm), warping as a difference in thickness between the end and the center. If the thickness is 0.5 mm or less, it is presumed that the substrate is manufactured by the method for manufacturing a multilayer wiring board.

Example 1
<Manufacturing method of multilayer wiring board>
Below, the manufacturing method of the multilayer wiring board based on Example 1 is demonstrated.

(1) Preparation of photosensitive paste In the present Example, the following materials were used for each material used for preparation of the photosensitive paste.
A. Inorganic powder A1. Silver powder: spherical, D50: 2.0 μm
A2. Glass powder a: SiO ₂ —B ₂ O ₃ —K ₂ O system, D50: 3.0 μm
A3. Glass powder b: SiO ₂ —B ₂ O ₃ —Li ₂ O ₃ —ZnO—Al ₂ O ₃ system, D50: 3.0 μm
A4. Quartz powder: D50: 3.0 μm
B. Monomer B1. Monomer a: Dipentaerythritol hexaacrylate B2. Monomer b: Ethoxy-modified trimethylolpropane triacrylate C.I. Polymer C1. Polymer a: Ethylenically unsaturated double bond-containing acrylic copolymer obtained by copolymerization of methacrylic acid / methyl methacrylate and then addition reaction of 0.2-fold molar amount of epoxycyclohexylmethyl methacrylate with respect to methacrylic acid Coalescence. MW = 20000, acid value = 100 mg KOH / g.
C2. Polymer b: An acrylic copolymer obtained by copolymerizing methacrylic acid / methyl methacrylate and then adding 0.2 times the molar amount of epoxyethylbenzene to methacrylic acid. MW = 24000, acid value = 90 mg KOH / g.
D. Photoinitiator D1. Initiator a: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one D2. Initiator b: 2,4-diethylthioxanthone D3. Initiator c: Ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl)-, 1- (o-acetyloxime)
D4. Initiator d: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide D5. Initiator e: 1-hydroxy-cyclohexyl-phenyl-ketone Organic solvent:
E1. Organic solvent a: pentamethylene glycol E2. Organic solvent b: dipropylene glycol monomethyl ether Other organic components F1. Dispersant: Aliphatic polycarboxylic acid amine salt (solid content 49%)
F2. Thixotropic agent: Polyamide (solid content 70%)
F3. Leveling agent: Special acrylic polymer (ethyl carbitol acetate solution, solid content 50%, SP value 8.81)
F4. Ultraviolet absorber: azo dye The above materials were weighed and mixed so as to have a weight ratio shown in Table 1 below. Next, kneading with a three-roll mill was performed to obtain samples of a photosensitive conductive paste and a photosensitive glass paste, respectively.

(2) Thin substrate adhesion onto a thick substrate A heat-curable epoxy resin adhesive is applied onto a 1.5 mm thick 4-inch alumina substrate (thick substrate). A 4-inch alumina substrate (thin substrate) having a thickness of 0.03 mm was adhered thereon and cured at a temperature of 150 ° C. for 1 hour.

(3) Lamination of Ag wiring / glass layer A photosensitive Ag paste was applied on the substrate by screen printing and dried at 100 ° C. for 10 minutes to form a coating film having a thickness of 15 μm. Next, the obtained coating film was exposed. Here, actinic rays from a high-pressure mercury lamp are applied at 1200 mJ / cm ² through a mask on which an Ag pattern (line width / line interval = 20 μm, 2-winding coil pattern) having a 50 μm-diameter pad at the pattern end is drawn. Irradiated with an exposure dose. Thereafter, an Ag pattern (line width / line interval = 20 μm, 2-winding coil pattern) having a pad portion with a diameter of 50 μm at the pattern end was formed by performing a development treatment with an aqueous sodium carbonate solution.
Next, a photosensitive glass paste was applied by screen printing and dried at 100 ° C. for 10 minutes to form a coating film having a thickness of 30 μm. Next, the obtained coating film was exposed. Here, actinic rays from a high-pressure mercury lamp were irradiated at an exposure amount of 100 mJ / cm ² through a mask on which a 30 μm diameter via pattern was drawn. Thereafter, a via pattern having a diameter of 30 μm was formed on the alumina substrate by developing with an aqueous sodium carbonate solution.
By repeating the above operation, an alumina substrate having an Ag6 layer and a glass 6 layer was produced. In addition, the via pattern design and the alignment of the glass via portion and the Ag pad portion at the time of exposure are appropriately performed so that the lowermost layer Ag and the uppermost layer Ag are electrically connected, and external electrodes are provided on the uppermost layer Ag and the lowermost layer Ag. It can be connected to the shape. Each pattern is set to be within 0.6 × 0.3 mm.
Through the above operation, the warp of the thin substrate could be kept within 0.5 mm, and there was no situation where the Ag layer / glass layer lamination became difficult.
As for the warp of the thin substrate, with respect to the thin substrate 2 having a length of 4 inches (10.16 cm), the end portion on the side where the wiring layer / insulating layer is laminated is lifted, and a concave portion is formed at the center of the laminated side. . On the contrary, when viewed from the non-laminated side, the central portion is lifted from the end portion and appears convex. Therefore, the maximum difference in thickness between the edge and the center of the thin substrate is measured, and this maximum difference is used as the warp of the thin substrate.

(4) Firing Cut grooves were formed at intervals of 0.6 × 0.3 mm with a dicer at a depth not reaching the thick substrate with respect to the substrate, and each pattern was separated. Here, the cutting depth is adjusted so as not to cut the thick substrate, but the thick substrate may be cut for each individual chip. Furthermore, after performing a degreasing process, it baked at 850 degreeC in the air for 1 hour. As a result, the adhesive was burned out and the cut thin substrate was separated from the thick substrate, and a 0.6 × 0.3 mm size multilayer wiring substrate was formed. By forming external electrodes on both ends of this multilayer wiring board, a chip coil having a size of 0.6 × 0.3 mm could be obtained.

(Comparative example)
After the formation of the first Ag layer and the first glass layer directly on the 0.03 mm-thick 4 inch alumina substrate in the step (3) without passing through the step (2), two layers are formed. A photosensitive Ag paste was applied to form an Ag layer for the eyes. Thereafter, the warp as a difference between the edge and the center of the thin substrate during drying was 1 mm or more, and it was difficult to further laminate the Ag layer and the glass layer.

<Action and effect>
According to the method for manufacturing a multilayer wiring board according to Example 1, even when the number of laminated glass insulating layers / wiring layers on the thin substrate is increased by adhering the thick substrate to the thin substrate, the warp during drying occurs. Stacking can be performed without increasing the size. On the other hand, in the comparative example, since the thick substrate was not bonded to the thin substrate, the shrinkage stress at the time of drying could not be resisted at the stage of applying the Ag paste for forming the second Ag layer, and the thin substrate The warpage was 1 mm or more, and it was difficult to laminate further.

  In addition, each embodiment and each Example are illustrations, and it cannot be overemphasized that the partial substitution or combination of the structure shown in different embodiment and Example is possible. The present disclosure includes appropriately combining any of the various embodiments described above, and can provide the effects of the respective embodiments.

  The method for manufacturing a multilayer wiring board according to the present invention can suppress the occurrence of warping even if the wiring layer / insulating layer is made multilayer. Therefore, it is used to manufacture electronic components such as coil components, chip inductors, capacitors, multilayer LC filters, functional modules such as VCO (Voltage Controlled Oscillator), PLL (Phase Locked Loop), and ceramic multilayer substrates. it can.

DESCRIPTION OF SYMBOLS 1 Thick board | substrate 2 Thin board | substrates 3a, 3b, 3c, 3d, 3e, 3f Wiring layer 4a, 4b, 4c, 4d, 4e, 4f Insulating layer 10 Multilayer wiring board

Claims (7)

(1) A thin substrate with a thickness of 50 μm or less is attached to a thick substrate with a thickness of 0.5 mm or more with an adhesive,
(2) A conductive paste containing a conductive material is printed and applied, and a pattern is formed on the printed conductive paste to form a wiring layer made of a conductor pattern;
(3) An insulating paste containing an insulating material is printed on the wiring layer to form an insulating layer;
(4) The above steps (2) and (3) are repeated a plurality of times,
(5) The thick substrate is peeled from the thin substrate to obtain a multilayer wiring substrate having a plurality of the wiring layers and the insulating layer on the thin substrate.
A method for manufacturing a multilayer wiring board. In the step of attaching the thin substrate to the thick substrate of (1), the thin substrate is attached to the thick substrate with an adhesive that burns away or loses adhesive strength by heating,
In the step of peeling the thick substrate from the thin substrate of (5), after drying the laminated wiring layer and the insulating layer, the adhesive is burned out or the adhesive force is lost, The method for manufacturing a multilayer wiring board according to claim 1, wherein the thick substrate is peeled from the thin substrate.   The method for manufacturing a multilayer wiring board according to claim 1, wherein the insulating paste is made of glass paste.   The method for manufacturing a multilayer wiring board according to claim 1, wherein the thin substrate and the thick substrate are alumina substrates. A thin substrate having a thickness of 50 μm or less;
A wiring layer comprising a conductor pattern;
An insulating layer provided on the wiring layer and made of an insulating material;
With
A multilayer wiring board having a plurality of sets of the wiring layer and the insulating layer on the thin substrate.   The multilayer wiring board according to claim 5, wherein the thin substrate is an alumina substrate.   The multilayer wiring board according to claim 5 or 6, wherein the multilayer wiring board constitutes a coil component.

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