JP2016092386A - Insulation sheet, wiring board and mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation sheet, a wiring board and a mounting structure, capable of improving bonding force between inorganic insulating particles.SOLUTION: Disclosed is an insulation sheet 1 which includes a sheet member 2 and a first insulation layer 4 arranged on the sheet member 2. The first insulation layer 4 includes: a plurality of inorganic insulation particles 6 whose parts are bonded to each other; and a first resin part 8 arranged between the plurality of inorganic insulation particles 6. The plurality of inorganic insulation particles 6 includes a first inorganic insulation particle 11 whose diameter is 5-80 nm, and a second inorganic insulation particle 12 whose diameter is 0.1-5 μm and have a functional group on the surface of the first inorganic insulation particle 11 and on the surface of the second inorganic insulation particle 12.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an insulating sheet, a wiring board, and a mounting structure used for electronic devices (for example, various audiovisual devices, home appliances, communication devices, computer devices and peripheral devices).

  2. Description of the Related Art Conventionally, as a mounting structure in an electronic device, an electronic component mounted on a wiring board is used. As an insulating sheet for forming such a wiring substrate, a first inorganic insulating particle having a particle size of 3 nm to 110 nm and a second particle having a particle size of 0.5 μm to 5 μm are formed on a support sheet (sheet member). What formed the inorganic insulating layer containing an inorganic insulating particle is described (refer patent document 1). This Patent Document 1 describes that the first inorganic insulating particles are bonded to each other, and the second inorganic insulating particles are bonded to each other through the first inorganic insulating particles and have a three-dimensional network structure skeleton. Yes.

International Publication No. 2011/037260

  In the insulating sheet of Patent Document 1, the bonding strength between the first inorganic insulating particles, the first inorganic insulating particles and the second inorganic insulating particles, and the second inorganic insulating particles is still low, and the inorganic insulating particles fall off during handling. There is a possibility that a problem may occur, and further improvement of the strength of the skeleton by the inorganic insulating particles has been demanded.

  The present invention provides an insulating sheet, a wiring board, and a mounting structure that can improve the bonding strength between inorganic insulating particles.

  The insulating sheet of the present invention is an insulating sheet comprising a sheet member and a first insulating layer disposed on the sheet member, wherein the first insulating layer includes a plurality of inorganic insulating particles bonded to one another. And a first resin portion disposed between the plurality of inorganic insulating particles, and the plurality of inorganic insulating particles include a first inorganic insulating particle having a particle size of 5 to 80 nm and a particle size of 0. The first inorganic insulating particles and the second inorganic insulating particles have the same functional group on the surface of the first inorganic insulating particles.

  A wiring board of the present invention is a wiring board comprising a first insulating layer, a second insulating layer disposed on the first insulating layer, and a conductive layer disposed on the second insulating layer. The first insulating layer includes a plurality of inorganic insulating particles bonded to each other and a first resin portion disposed between the plurality of inorganic insulating particles, and the plurality of inorganic insulating layers. The particles include first inorganic insulating particles having a particle size of 5 to 80 nm and second inorganic insulating particles having a particle size of 0.1 to 5 μm. The surface of the first inorganic insulating particles and the second inorganic insulating particles It has the same functional group on the surface of this.

  A mounting structure according to the present invention includes the above wiring board and an electronic component mounted on the wiring board and electrically connected to the conductive layer.

  According to the insulating sheet of the present invention, since the surface of the first inorganic insulating particle and the surface of the second inorganic insulating particle have the same functional group, the functional group of the first inorganic insulating particle and the second inorganic insulating particle By bonding or intertwining each other, the bonding strength between the first inorganic insulating particles, the second inorganic insulating particles, and the first inorganic insulating particles and the second inorganic insulating particles can be improved. Thereby, the intensity | strength of a 1st insulating layer can be improved and the possibility that problems, such as an insulating particle falling off at the time of handling, may be avoided.

FIG. 1 is a cross-sectional view schematically showing an insulating sheet according to an embodiment of the present invention. (A) (b) is sectional drawing which shows typically the interface part of the sheet | seat member of FIG. 1, and an insulating layer, (c) shows the interface part of the 1st insulating layer and 2nd insulating layer of FIG. It is sectional drawing shown typically. It is sectional drawing which shows the 1st insulating layer of FIG. 1 typically. It is sectional drawing which showed the outline of the wiring board which concerns on one Embodiment of this invention. It is sectional drawing which showed 1 process of the manufacturing method of the wiring board of FIG. It is sectional drawing which showed 1 process of the manufacturing method of the wiring board of FIG. It is sectional drawing which showed 1 process of the manufacturing method of the wiring board of FIG.

  Hereinafter, an insulating sheet according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The present invention is not limited to the following embodiments, and various changes and improvements can be made without departing from the scope of the present invention.

  FIG. 1 schematically shows a cross section of the insulating sheet 1 cut in the vertical direction (thickness direction of the insulating sheet). The insulating sheet 1 is used, for example, for manufacturing a wiring board as will be described later. As shown in FIG. 1, the insulating sheet 1 includes a sheet member 2 and an insulating layer 3 laminated on the sheet member 2.

  The sheet member 2 supports the insulating layer 3 when the insulating sheet 1 is handled. The sheet member 2 is peeled from the insulating layer 3 or processed into a wiring when the wiring board is manufactured. The sheet member 2 has, for example, a flat plate shape. The sheet member 2 is made of, for example, a metal material such as copper, or a resin material such as a thermoplastic resin such as polyethylene terephthalate resin, polyethylene naphthalate resin, polyester resin, polyimide resin, or polyethylene resin. When the sheet member 2 is made of a resin material, generation of wrinkles and the like of the sheet member 2 can be reduced. On the other hand, when the sheet member 2 is made of a metal material, the heat resistance of the sheet member 2 can be improved.

  As shown in FIG. 2A, the sheet member 2 has an insulating layer 3 laminated on the main surface of the flat sheet member 2. In order to improve the adhesive strength with the insulating layer 3, as shown in FIG. 2C, a plurality of recesses 10 are formed on the main surface of the sheet member 2 to increase the contact area with the insulating layer 3. Good. In the cross section along the vertical direction, each opening width of the recess 10 is set to, for example, 0.01 μm or more and 10 μm or less. In addition, the opening width of the recessed part 10 can be measured with a laser displacement meter, an atomic force microscope (ASM), or a scanning electron microscope (SEM). Hereinafter, the case where the insulating layer 3 is formed directly on the sheet member 2 made of a resin material will be described.

The thickness of the sheet member 2 made of a resin material is set to 3 μm or more and 100 μm or less, for example. The Young's modulus of the sheet member 2 is set to 0.5 GPa or more and 12 GPa or less, for example. The thermal expansion coefficient of the sheet member 2 is set to 20 ppm / ° C. or more and 120 ppm / ° C. or less, for example. The Young's modulus of the sheet member 2 is measured using Nano Indentor XP / DCM manufactured by MTS Systems. Moreover, the thermal expansion coefficient of the sheet | seat member 2 is measured by the measuring method according to JISK7197-1991 using a commercially available TMA apparatus.

  The insulating layer 3 ensures insulation between the wirings of the produced wiring board. The insulating layer 3 has a first insulating layer 4 stacked on the surface of the sheet member 2 and a second insulating layer 5 stacked on the first insulating layer 4. The thickness of the insulating layer 3 is set to, for example, 5 μm or more and 50 μm or less, desirably 8 μm or more and 20 μm or less.

  The first insulating layer 4 may play a role of roughening the surface of the insulating layer 3 by removing a part of the surface layer when the wiring board is manufactured. The first insulating layer 4 is, for example, layered. The thickness of the first insulating layer 4 is set to, for example, 1 μm or more and 15 μm or less.

  As shown in FIG. 2, the first insulating layer 4 is formed by a plurality of inorganic insulating particles 6 and a first resin portion 8. Specifically, the plurality of inorganic insulating particles 6 are bonded to each other while maintaining the particle shape (concept including contact), thereby forming a skeleton that is a main part of the first insulating layer 4. Since the plurality of inorganic insulating particles 6 are bonded to each other while maintaining the particle shape, there are gaps 7 between the plurality of inorganic insulating particles 6. A resin is disposed in the gap 7 to form a first resin portion 8.

  Some of the inorganic insulating particles 6 of the first insulating layer 4 have a contact portion 9 in contact with the sheet member 2. Further, since the plurality of inorganic insulating particles 6 are bonded to each other while maintaining the particle shape, the gap 7 is an open pore penetrating over both main surfaces of the first insulating layer 4. The first resin portion 8 disposed in the gap 7 is not only disposed in the gap 7 but also in contact with the sheet member 2. In other words, the first resin portion 8 is disposed between the plurality of inorganic insulating particles 6, and is a portion other than the contact portion 9 on the surface of the plurality of inorganic insulating particles 6 and one main surface of the sheet member 2. It touches. Thereby, when the sheet member 2 is peeled, the inorganic insulating particles 6 having the contact portions 9 are exposed. As a result, since the surface of the insulating layer 3 can be roughened by dissolving the inorganic insulating particles 6, the size of the recesses on the surface of the insulating layer 3 during the roughening treatment can be controlled by controlling the size of the inorganic insulating particles 6. Can be controlled. Therefore, the concave portion on the surface of the insulating layer 3 formed by the roughening treatment can be easily formed small, and for example, formation of fine wiring can be facilitated.

  In addition, the adhesive strength between the sheet member 2 and the insulating layer 3 can be improved by bringing the first resin portion 8 into contact with the sheet member 2 at the stage of the insulating sheet 1 before producing the wiring board. As a result, peeling of the insulating layer 3 from the sheet member 2 can be reduced, and the handling of the insulating sheet 1 can be facilitated.

  Moreover, since the 1st insulating layer 4 has couple | bonded several inorganic insulating particles 6, compared with the case where the several inorganic insulating particle 6 is simply disperse | distributed in resin, the 1st insulating layer 4 Stiffness can be improved. As a result, since deformation of the insulating layer 3 including the first insulating layer 4 can be reduced, for example, when the sheet member 2 is peeled off, distortion of the insulating layer 3 can be reduced.

  Moreover, when the some recessed part 10 is formed in the sheet | seat member 2, the inorganic insulating particle 6 may be contacting the inner surface of the recessed part 10. FIG. As a result, when the wiring board is formed, the insulating layer 3 can be formed with a convex portion corresponding to the concave portion 10 and a plurality of fine concave portions on the surface of the convex portion, and the insulating layer 3 and the wiring or the insulating layer 3 and the other insulating layer 3 laminated | stacked on this insulating layer 3 can be improved.

The inorganic insulating particles 6 are first particles having a particle diameter smaller than that of the opening of the recess 10 of the sheet member 2.
The inorganic insulating particles 11 and the second inorganic insulating particles 12 having a particle diameter larger than the opening of the recess 10 of the sheet member 2 may be included. As a result, the first inorganic insulating particles 11 can enter the recess 10, and the second inorganic insulating particles 12 do not enter the recess 10. As a result, the first inorganic insulating particles 11 contribute to the roughening of the insulating layer 3 and the second inorganic insulating particles 12 can improve the rigidity and the like of the insulating layer 3.

  The particle diameter of the first inorganic insulating particles 11 is set to 5 nm or more and 80 nm or less. The particle diameter of the second inorganic insulating particles 12 is set to 0.1 μm or more and 5 μm or less. As for the particle diameter of the inorganic insulating particles 6 (first inorganic insulating particles 11 and second inorganic insulating particles 12), for example, first, the cross section of the first insulating layer 4 is observed with a transmission electron microscope (TEM), and the number of particles is 20 or more. It is calculated by photographing a cross section enlarged so as to include particles of 50 particles or less and measuring the maximum diameter of each particle in the enlarged cross section.

  For example, the first inorganic insulating particles 11 are included in the plurality of inorganic insulating particles 6 by 10 volume% or more and 40 volume% or less, and the second inorganic insulating particles 12 are, for example, 60 volumes in the plurality of inorganic insulating particles 6. % Or more and 90% by volume or less. As described above, if the particle size distribution of the plurality of inorganic insulating particles 6 is set, the gap 7 of the first insulating layer 4 is suppressed from becoming too small, and the resin of the second insulating layer 5 described later is applied to the sheet portion 2. It can be made easy to enter until it comes into contact. More preferably, the particle diameter of the first inorganic insulating particles 11 is set to 8 nm or more and 70 nm or less, and the plurality of inorganic insulating particles 6 are contained in 15% by volume or more and 30% by volume or less. The particle diameter of 12 is set to 0.15 μm or more and 2 μm or less, and 70% by volume or more and 85% by volume or less may be contained in the plurality of inorganic insulating particles 6.

  The inorganic insulating particles 6 form the main part (skeleton) of the first insulating layer 4. The shape of the inorganic insulating particles 6 is, for example, spherical. The inorganic insulating particles 6 are made of an inorganic insulating material such as silicon oxide, aluminum oxide, titanium oxide, magnesium oxide, or zirconium oxide. The inorganic insulating particles 6 may be made of a single material or a plurality of types of materials. The inorganic insulating particles 6 are made of a material having a coefficient of thermal expansion of, for example, not less than 0.6 ppm / ° C. and not more than 12 ppm / ° C. The inorganic insulating particles 6 are made of a material having a Young's modulus of, for example, 10 GPa or more and 300 GPa or less. Moreover, the content rate with respect to the 1st insulating layer 4 of the some inorganic insulating particle 6 is set, for example to 70 volume% or more, Preferably it is set to 75 volume% or more.

  The first resin portion 8 is made of, for example, a thermosetting resin such as an epoxy resin, a bismaleimide triazine resin, a cyanate resin, a polyphenylene ether resin, a wholly aromatic polyamide resin, or a polyimide resin, and the first resin portion 8 is For example, it is made of a material having a thermal expansion coefficient of 30 ppm / ° C. or more and 60 ppm / ° C. or less. The first resin portion 8 is made of a material having a Young's modulus of, for example, 2 GPa or more and 10 GPa or less. The first resin portion 8 is uncured or semi-cured in the insulating sheet 1.

  The second insulating layer 5 is for bonding the insulating layer 3 and the wiring, or the insulating layer 3 and another insulating layer 3 laminated on the insulating layer 3 at the time of manufacturing the wiring board. The 2nd insulating layer 5 has the inorganic filler 35 distribute | arranged in the resin of the 2nd resin part 13 and the 2nd resin part 13, as shown in FIG.2 (c).

  The thickness of the second insulating layer 5 may be smaller than the thickness of the first insulating layer 4. Thereby, the influence of the thermal expansion of the 2nd insulating layer 5 becomes small, and the 1st insulating layer 4 can reduce the amount of thermal expansion of the 2nd insulating layer 5 effectively. The thickness of the second insulating layer 5 is set to, for example, 1 μm or more and 40 μm or less.

  The second resin portion 13 of the second insulating layer 5 may be in contact with the first resin portion 8 of the first insulating layer 4. As a result, the adhesive strength between the second insulating layer 5 and the first insulating layer 4 can be improved, and for example, peeling due to a difference in thermal expansion coefficient between the first insulating layer 4 and the second insulating layer 5 can be reduced. it can.

  The second resin portion 13 of the second insulating layer 5 may be formed integrally with the first resin portion 8 of the first insulating layer 4. That is, the resin forming the second insulating layer 5 may enter the gap 7 of the first insulating layer 4 to form the first resin portion 8. As a result, peeling between the second insulating layer 5 and the first insulating layer 4 can be effectively reduced.

  The second resin portion 13 mainly constitutes the second insulating layer 5. The second resin portion 13 is made of, for example, a thermosetting resin such as an epoxy resin, a bismaleimide triazine resin, a cyanate resin, a polyphenylene ether resin, a wholly aromatic polyamide resin, or a polyimide resin. The second resin portion 13 is made of a material having a thermal expansion coefficient of, for example, 30 ppm / ° C. or more and 60 ppm / ° C. or less. The second resin portion 13 is made of a material having a Young's modulus of, for example, 2 GPa or more and 10 GPa or less. The second resin portion 13 is in an uncured state or a semi-cured state in the insulating sheet 1.

  The inorganic filler 35 improves the strength of the second insulating layer 5. The shape of the inorganic filler 35 is, for example, spherical. The particle diameter of the inorganic filler 35 may be equal to or larger than the particle diameter of the second inorganic insulating particles 12. The particle diameter of the inorganic filler 35 is set to 0.1 μm or more and 5 μm or less, for example. The content of the inorganic filler 35 with respect to the second insulating layer 5 may be smaller than the content of the inorganic insulating particles 6 with respect to the first insulating layer 4. The content of the inorganic filler with respect to the second insulating layer 5 is set to 60% by volume or less, for example.

  And the surface of the 1st inorganic insulating particle 11 in the 1st insulating layer 4 and the surface of the 2nd inorganic insulating particle 12 are coupling-processed as shown in FIG. The same functional group is present on the surface of the second inorganic insulating particle 12. The functional group is desirably chemically bonded to the surfaces of the first and second inorganic insulating particles 11 and 12. Thereby, the functional groups of the first inorganic insulating particles 11 and the second inorganic insulating particles 12 are bonded or entangled with each other, so that the first inorganic insulating particles 11, the second inorganic insulating particles 12, and the first inorganic insulating particles are combined. The particles 11 and the second inorganic insulating particles 12 can be firmly bonded to form a strong skeleton.

  The functional group is other than a hydroxyl group or an oxane group, for example, a hydrocarbon group, a methacryl group, an acryl group, or the like, which is a so-called organic functional group.

  As such a coupling treatment, for example, a silane coupling treatment or a titanate coupling treatment can be used.

In particular, by performing a coupling treatment using an excess coupling agent, the same functional group can be present on the surfaces of the first and second inorganic insulating particles 11 and 12, and an excess coupling agent is present. It exists between the first and second inorganic insulating particles 11 and 12 in a free state, and is dispersed in the resin when the resin is pressed into the skeleton (gap 7), and in the first resin portion 8 of the gap 7. The coupling agent containing the same functional group as the functional group attached to the surfaces of the first and second inorganic insulating particles 11 and 12 exists. Thereby, through the coupling agent containing the same functional group dispersed in the first resin portion 8, the first inorganic insulating particles 11 and the second inorganic insulating particles 12 are combined, or the coupling agents are entangled with each other, The first inorganic insulating particles 11, the second inorganic insulating particles 12, and the first inorganic insulating particles 11 and the second inorganic insulating particles 12 can be further strongly bonded to form a stronger three-dimensional network structure skeleton. . Regarding the dispersant described later, not only the surfaces of the first and second inorganic insulating particles 11 and 12 but also the first and second inorganic insulating particles 11 and 12.
It is desirable to be distributed between them.

  In addition, in order to make a functional group exist in the 1st resin part 8, in addition to processing the inorganic insulation particle 6 using an excess coupling agent, it couples beforehand in resin which comprises the 1st resin part 8. An agent may be added.

  Whether or not the same functional group is present on the surfaces of the first and second inorganic insulating particles 11 and 12, and the same functional group as that present on the surfaces of the first and second inorganic insulating particles 11 and 12 Whether a coupling agent having a functional group is present in the first resin portion 8 can be confirmed by FT-IR (Fourier transform infrared spectroscopy), MMR (nuclear magnetic resonance), and various titrations.

  In addition, although the functional group by a coupling agent was demonstrated in the said form, the functional group by a dispersing agent may be sufficient, and of course, the functional group by a coupling agent and a dispersing agent may be sufficient. Moreover, the functional group by a coupling agent and the functional group by a dispersing agent may be different functional groups.

  Next, the wiring board 14 manufactured using the insulating sheet 1 described above will be described in detail with reference to FIG. FIG. 4 schematically shows a cross section of the wiring board cut in the vertical direction.

  The wiring board 14 is used for electronic devices such as various audiovisual devices, home appliances, communication devices, computer devices or peripheral devices thereof. The wiring board 14 is, for example, a build-up multilayer wiring board, and includes a core substrate 15 and a pair of wiring layers 16 formed above and below the core substrate 15 as shown in FIG.

  The core substrate 15 is intended to enhance electrical connection between the pair of wiring layers 16 while increasing the rigidity of the wiring substrate 14. The core substrate 15 includes a resin base 17, a cylindrical through-hole conductor 18 formed so as to penetrate the resin base 17 in the vertical direction, and a columnar insulator disposed in a region surrounded by the through-hole conductor 18. 19 is included.

  The resin base 17 increases the rigidity of the core substrate 15. The resin substrate 17 includes, for example, a resin, a base material coated with the resin, and an inorganic insulating filler.

  The resin contained in the resin substrate 17 forms the main part of the resin substrate 17. Examples of this resin include epoxy resin, bismaleimide triazine resin, cyanate resin, polyparaphenylene benzbisoxazole resin, wholly aromatic polyamide resin, polyimide resin, aromatic liquid crystal polyester resin, polyether ether ketone resin, or polyether ketone resin. Made of resin material.

  The base material contained in the resin base 17 is to make the resin base 17 highly rigid and low in thermal expansion. This base material consists of what arranged the woven fabric or nonwoven fabric comprised by the fiber, or the fiber in one direction. Moreover, this fiber consists of glass fiber or resin fiber, for example.

  The inorganic insulating filler contained in the resin substrate 17 makes the resin substrate 17 highly rigid and low in thermal expansion. The inorganic insulating filler is composed of a plurality of particles made of an inorganic insulating material such as silicon oxide, aluminum oxide, aluminum nitride, aluminum hydroxide, or calcium carbonate.

  The through-hole conductor 18 is for electrically connecting the upper and lower wiring layers 16 of the core substrate 15. The through-hole conductor 18 is made of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium.

  The insulator 19 forms a support surface of a via conductor 20 described later. The insulator 19 is made of, for example, a resin material such as polyimide resin, acrylic resin, epoxy resin, cyanate resin, fluorine resin, silicon resin, polyphenylene ether resin, or bismaleimide triazine resin.

  On the other hand, a pair of wiring layers 16 are formed above and below the core substrate 15 as described above. The wiring layer 16 includes an insulating layer 3 in which a via hole is formed along the thickness direction, a wiring 21 partially formed on the resin substrate 17 or the insulating layer 3, and a via conductor formed in the via hole. 20 and so on.

  The insulating layer 3 includes a second insulating layer 5 located on the core substrate 15 side and a first insulating layer 4 stacked on the second insulating layer 5. The first insulating layer 4 and the second insulating layer 5 are provided in the above-described insulating sheet 1. Further, the first resin portion 8 of the first insulating layer 4 and the second resin portion 13 of the second insulating layer 5 are uncured on the insulating sheet 1, but the first resin portion 8 and the second resin portion 13 of the wiring substrate 14 are uncured. 2 The resin portion 13 is cured.

  The second insulating layer 5 adheres the resin substrate 17 and the insulating layer 3 or adheres the laminated insulating layers 3 to each other while adhering to the side surface and the upper surface of the wiring 21. The first insulating layer 4 is a main part of the insulating layer 3 and functions as an insulating member between the wirings 21 that are arranged apart in the thickness direction. Since the first insulating layer 4 has a low coefficient of thermal expansion and high rigidity compared to the resin material, the coefficient of thermal expansion in the planar direction of the insulating layer 3 can be reduced. Therefore, the difference in the thermal expansion coefficient in the plane direction between the wiring board 14 and the electronic component (not shown) mounted on the wiring board 14 can be reduced, and consequently the warpage of the wiring board 14 can be reduced.

  The wirings 21 are arranged apart from each other along the planar direction or the thickness direction, and function as grounding wirings, power supply wirings, or signal wirings. The wiring 21 is made of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium. The thickness of the wiring 21 is set to 3 μm or more and 20 μm or less, for example. The coefficient of thermal expansion of the wiring 21 is set to, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less. The L / S (line / space) of the wiring 21 is set to 3/3 μm or more and 20/20 μm or less, for example.

  The via conductor 20 electrically connects the wirings 21 that are spaced apart from each other in the thickness direction, and is formed in a column shape that becomes narrower toward the core substrate 15. The via conductor 20 is made of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium, for example. The via conductor 20 has a thermal expansion coefficient set to, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less.

  The manufacturing method of the wiring board 14 using the insulating sheet 1 which concerns on embodiment of this invention is demonstrated, referring FIGS. The method for manufacturing a wiring board mainly includes a preparation process, a lamination process, an exposure process, a roughening process, and a wiring formation process. The present invention is not limited to the following embodiments, and various changes and improvements can be made without departing from the scope of the present invention. 5-7 is sectional drawing which showed 1 process of the manufacturing method of the wiring board manufactured using the insulating sheet which concerns on one Embodiment of this invention.

  (1) First, the insulating sheet 1 is prepared. The insulating sheet 1 is prepared through the following steps (2) to (4).

(2) A plurality of inorganic insulating particles 6 and water or an organic solvent and an appropriate dispersant are prepared, weighed and mixed to prepare a slurry containing the inorganic insulating particles 6. The first and second inorganic insulating particles 11 and 12 that are the plurality of inorganic insulating particles 6 are subjected to coupling treatment and have the same functional group on the surface thereof. The slurry contains, for example, 10% by volume or more and 60% by volume or less of the inorganic insulating particles 6, and contains 40% by volume or more and 90% by volume or less of water or an organic solvent and a dispersant. The organic solvent is selected from, for example, methanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol monopropyl ether, methyl ethyl ketone, methyl isobutyl ketone, xylene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide or the like. Alternatively, an organic solvent containing a mixture of two or more kinds can be used.

  Examples of the dispersant include known dispersants such as cationic, anionic and nonionic.

  (3) The sheet member 2 is formed, for example, by molding a resin into a sheet shape by extrusion molding or the like. In order to form the recess 10 in the sheet member 2, if the sheet member 2 is a copper foil, by controlling the conditions when the copper foil is formed by plating, It can be formed by dissolving in an aqueous solution such as potassium manganate or sodium permanganate.

  Next, the slurry is directly formed (coated) into a sheet shape on the sheet member 2 made of a resin material. As the forming method, an existing forming method such as a doctor blade method, a dispenser method, a bar coater method, a die coater method or a gravure printing method is used, and water or a solvent is removed by drying. The first insulating layer Four skeletons can be formed.

  (4) The second insulating layer 5 is formed on the skeleton of the first insulating layer 4. Specifically, first, a mixture of a solvent, an inorganic filler, and an uncured resin is applied to the main surface of the skeleton of the first insulating layer 4. Next, the second insulating layer 5 is formed by drying the mixture applied to the main surface of the first insulating layer 4 and evaporating the solvent from the mixture. Application of the mixture can be performed using an existing molding method such as a doctor blade method, a dispenser method, a bar coater method, a die coater method, or a gravure printing method.

  A part of the second insulating layer 5 (a part of the second resin part 13) enters the gap 7 of the skeleton of the first insulating layer 4 to form the first resin part 8. Specifically, the sheet member 2, the skeleton of the first insulating layer 4, and the second insulating layer 5 are heated and pressurized in the vertical direction, so that the second insulating layer 5 (second resin) is formed in the gap 7 of the first insulating layer 4. Part 13) is inserted. The heating temperature of the sheet member 2 or the like is set to 60 ° C. or more and 160 ° C. or less, for example. The pressurizing pressure of the sheet member 2 or the like is set to, for example, 0.1 MPa or more and 2 MPa or less. The heating and pressing time for the sheet member 2 or the like is set to, for example, not less than 0.5 minutes and not more than 10 minutes. The melt viscosity of the resin material of the second insulating layer 5 during the heating time is set to 10,000 Pa · s or less, for example. By appropriately adjusting the thickness of the skeleton of the first insulating layer 4, the pressure applied to the sheet member 2 and the like, and the melt viscosity of the resin material of the second insulating layer 5, the resin that enters the gap 7 of the first insulating layer 5 ( The first resin part 8) can be brought into contact with the sheet member 2.

  Alternatively, the second insulating layer 5 is formed on a carrier film similar to that of the sheet member 2 and a mixture of the aforementioned solvent, inorganic filler, and uncured resin is formed into a sheet shape by the same existing molding method as described above. Can be placed on a part of the second insulating layer 5 (a part of the second resin portion 13), and heated and pressurized in the same manner as described above to form the gap 7 in the first insulating layer 4. Part of the second insulating layer 5 (second resin portion 13) can be allowed to enter.

  As described above, the insulating sheet 1 including the sheet member 2, the first insulating layer 4, and the second insulating layer 5 is produced.

  (5) The core substrate 15 (substrate) is produced. For production of the core substrate 15, first, for example, a resin substrate 17 in which a plurality of resin layers are laminated on a metal foil is formed. Next, after a through hole is formed in the resin substrate 17 by, for example, drilling or laser processing, a cylindrical shape is formed on the inner wall of the through hole by, for example, electroless plating, electroplating, vapor deposition, CVD, or sputtering. A through-hole conductor 18 is formed. Next, an insulator 19 is formed by filling a region surrounded by the through-hole conductor 18 with a resin material, and a conductive material is deposited on the exposed portion of the insulator 19, and then a conventionally known photolithography technique or etching is performed. The wiring 21 is formed by patterning the metal foil.

  The core substrate 15 is prepared as described above.

  (6) As shown in FIG. 5, the insulating sheet 1 is laminated on the core substrate 15. Specifically, the insulating sheet 1 is laminated so that the second insulating layer 5 of the insulating sheet 1 is in contact with the core substrate 15.

  (7) The first resin portion 8 and the second resin portion 13 are thermoset. Specifically, by heating the insulating sheet 1 and the core substrate 15 at a temperature equal to or higher than the thermosetting start temperature of the first resin portion 8 and the second resin portion 13, the uncured first resin portion 8 in the insulating sheet 1. And the 2nd resin part 13 is thermosetted. The heating temperature of the insulating sheet 1 etc. is set to 80 ° C. or higher and 180 ° C. or lower, for example.

  (8) The sheet member 2 is removed from the insulating sheet 1 laminated on the core substrate 15. The sheet member 2 is removed by, for example, mechanical peeling. By peeling off the sheet member 2, the first insulating layer 4 laminated on the sheet member 2 is exposed on the surface as shown in FIG.

  (9) As shown in FIG. 7, a through-hole penetrating the first insulating layer 4 and the second insulating layer 5 in the thickness direction from the surface of the first insulating layer 4 is formed. The through hole is formed by irradiating the upper surface of the first insulating layer 4 with laser light using, for example, a YAG laser device or a carbon dioxide laser device.

  (10) A part of the surface layer of the first insulating layer 4 (a part of the inorganic insulating particles 6) is removed. By removing a part of the surface of the first insulating layer 4, the surface of the insulating layer 3 can be roughened. For example, if the inorganic insulating particles 6 are made of silicon oxide, the surface of a part of the first insulating layer 4 is removed with a strong alkaline aqueous solution that dissolves the inorganic insulating particles 6. Simultaneously with the removal of a part of the surface of the first insulating layer 4, the surface treatment of the through hole is performed. The strong alkaline aqueous solution is, for example, an aqueous solution of potassium permanganate or sodium permanganate. Note that the second insulating layer 5 is made of a material that is hardly soluble in the aqueous solution because part of the inorganic insulating particles 6 of the first insulating layer 4 is removed while the second insulating layer 5 remains. At this time, the degree of roughening can be adjusted by forming the inorganic insulating particles 6 from a plurality of materials. The degree of roughening can also be adjusted by mixing inorganic insulating particles 6 made of different single materials such as aluminum oxide in the plurality of inorganic insulating particles 6.

  (11) The via conductor 20 is formed in the through hole. The via conductor 20 is formed by filling a conductive material in the through hole using, for example, electroless plating, vapor deposition, CVD, or sputtering.

(12) The wiring 21 is formed on the roughened surface of the first insulating layer 4 whose surface is roughened. Specifically, first, a conductive material is deposited on the first insulating layer 4 using, for example, an electroless plating method. Next, the wiring 21 can be formed on the first insulating layer 4 by patterning the conductive material deposited on the first insulating layer 4 using, for example, a photolithography technique or an etching technique.

  As described above, the wiring board 14 as shown in FIG. 4 is manufactured.

  In the above embodiment, the first insulating layer 4 is formed directly on the surface of the sheet member 2 made of a resin material. However, even if a resin layer is formed between the sheet member 2 and the first insulating layer 4. The effect of the present invention is that the bonding strength between the plurality of inorganic insulating particles 6 can be improved.

  In the above embodiment, the sheet member 2 made of a resin material is used, and the sheet member 2 is peeled to separately form the wiring 21. However, the present invention is a sheet member made of a metal material (copper foil). 2, even if the sheet member 2 is partly removed by etching or the like and the sheet member 2 itself is used as the wiring 21, the bonding force between the plurality of inorganic insulating particles 6 can be improved. Of course, it has an effect.

  The insulating sheet and wiring board when using the sheet member 2 made of copper foil will be described. First, the slurry for forming the skeleton of the first insulating layer 4 is applied to the surface of the sheet member 2, and the resin constituting the second insulating layer 5 is applied onto the skeleton of the first insulating layer 4. Then, a part of this resin enters the gap 7 of the skeleton of the first insulating layer 4, and the second insulating layer 5 is formed on the first insulating layer 4 to produce an insulating sheet.

  In this case, the same functional group can be present on the surface of the inorganic insulating particle 6, and the functional group is allowed to be present between the inorganic insulating particles 6 to bond the inorganic insulating particle 6 and the sheet member 2. By doing so, the bonding strength between the first inorganic insulating particles 11 of the first insulating layer 4 and the sheet member 2 can be improved.

  Then, this insulating sheet is laminated so that the second insulating layer 5 of the insulating sheet is in contact with the core substrate 15. Thereafter, through holes are formed through the sheet member 2, the first insulating layer 4, and the second insulating layer 5 in the thickness direction from the surface of the sheet member 2, and the surface treatment of the through holes is performed. In the case of silicon oxide, a strong alkaline aqueous solution that dissolves the inorganic insulating particles 6 is used.

  Thereafter, the via conductor 20 is formed in the through hole, and the wiring member 21 is formed on the first insulating layer 4 by etching the sheet member 2 made of copper foil using, for example, a photolithography technique.

  When the surface of the insulating layer 3 is roughened, a part of the surface layer of the first insulating layer 4 exposed by removing a part of the sheet member 2 by etching (a part of the inorganic insulating particles 6) is removed. The surface of the insulating layer 3 can be roughened by removing. For example, if the inorganic insulating particles 6 are made of silicon oxide, the surface of a part of the first insulating layer 4 is removed with a strong alkaline aqueous solution that dissolves the inorganic insulating particles 6. Next, an uncured second insulating layer of the insulating sheet 1 is further formed on the roughened surface of the first insulating layer 4 whose surface is roughened and the surface of the wiring layer 21 to form a plurality of insulating layers 3. 5 are stacked to form a plurality of insulating layers 3. The uncured second insulating layer 5 can be firmly bonded to the roughened surface of the first insulating layer 4 by the anchor effect.

  In addition, when using the sheet member 2 which consists of copper foils, when forming the 1st insulating layer 4 after forming the resin layer on the surface of the sheet member 2, joining of the sheet member 2 and the 1st insulating layer Strength can be improved.

  An electronic component is arranged on the upper surface of the wiring board 14 formed in this way, and the electronic component is mounted on the wiring 21 via a bonding member such as a bump or solder, thereby producing a mounting structure.

  The present invention is not limited to the above-described embodiments, and various changes, improvements, combinations, and the like can be made without departing from the spirit of the present invention.

  In the embodiment of the present invention described above, when the sheet member 2 is made of a resin material, only one insulating layer 3 is laminated. When the sheet member 2 is made of copper foil, the insulating layer 3 is 2 Although the configuration in which the layers are stacked has been described as an example, any number of insulating layers 3 may be stacked.

  Moreover, although embodiment of this invention mentioned above demonstrated the example which forms the 1st resin part 8 and the 2nd resin part 13 integrally, the 1st resin part 8 and the 2nd resin part 13 are formed separately. It doesn't matter. In this case, the second insulating layer 5 (second resin portion) is formed after the first resin portion 8 is disposed in the gap 7.

  Moreover, although embodiment of this invention mentioned above demonstrated the structure which manufactured the buildup multilayer wiring board using the insulating sheet 1 as an example, the wiring board manufactured using the insulating sheet 1 may be another. . Examples of the other wiring substrate include an interposer substrate, a coreless substrate, and a single layer substrate. Here, the interposer substrate includes one insulating layer 3, a through conductor that penetrates the insulating layer 3, and a wiring 21 that is disposed on the insulating layer 3 and is electrically connected to the through conductor. It is a wiring board. The coreless substrate includes the insulating layer 3, the via conductor 20 that penetrates the insulating layer 3, and the wiring 21 that is disposed on the insulating layer 3 and electrically connected to the via conductor 20. A wiring board in which a plurality of wirings 21 are alternately stacked and does not have the core substrate 15.

  In the above embodiment, the first insulating layer 4 has been described in the case where the surface layer of the insulating layer 3 is roughened by removing a part of the surface layer when the wiring substrate is manufactured. It may be a case where a part of the surface layer of the insulating layer 4 is not removed.

  Furthermore, although the said form demonstrated the case where the 1st, 2nd inorganic insulating particles 11 and 12 were included in the 1st insulating layer 4, it contains inorganic insulating particles other than the 1st and 2nd inorganic insulating particles 11 and 12. May be. It is desirable that the inorganic insulating particles are also subjected to a coupling treatment.

  As the sheet member, first and second inorganic insulating particles having a functional surface shown in Table 1 introduced on the particle surface were prepared by applying a copper foil having a thickness of 18 μm and an average particle size shown in Table 1 and a silane coupling treatment. Thereafter, the first and second inorganic insulating particles having the composition shown in Table 1 and MEK (methyl ethyl ketone) as a solvent were mixed to prepare a slurry.

  This slurry was shaped and dried on the surface of the sheet member using a doctor blade method so as to have a thickness of 5 μm, and a skeleton of the first insulating layer was produced. Sample No. No. 6 used a sheet member made of a resin material. The first insulating layer includes first inorganic insulating particles having a particle diameter of 5 to 80 nm and second inorganic insulating particles having a particle diameter of 0.1 to 5 μm. The first inorganic insulating particles and the second inorganic insulating particles The surface of the particles had the functional groups shown in Table 1.

  An adhesive tape was applied so as to sandwich the skeleton of the first insulating layer and the copper foil, and the peel strength when the adhesive tape was peeled off was measured with an autograph. The pressure-sensitive adhesive tape was peeled off so that the pressure-sensitive adhesive tape on the skeleton side of the first insulating layer carried a part of the inorganic insulating particles constituting the skeleton. The results are shown in Table 1.

  From Table 1, when the surfaces of the first and second inorganic insulating particles have the same functional group, the bonding strength between the first and second inorganic insulating particles is improved, and the strength of the skeleton of the first insulating layer is increased. I understand that.

  First and second inorganic insulating particles having a functional group shown in Table 2 introduced on the particle surface by applying a copper foil having a thickness of 18 μm as a sheet member and an average particle size and silane coupling treatment shown in Table 2 were prepared. Thereafter, first and second inorganic insulating particles having the composition shown in Table 2, MEK (methyl ethyl ketone) as a solvent, and a dispersant having a functional group shown in Table 2 were mixed to prepare a slurry.

  This slurry was shaped and dried on the surface of the sheet member using a doctor blade method so as to have a thickness of 5 μm, and a skeleton of the first insulating layer was produced. Sample No. No. 13 used a sheet member made of a resin material. The first insulating layer includes first inorganic insulating particles having a particle diameter of 5 to 80 nm and second inorganic insulating particles having a particle diameter of 0.1 to 5 μm. The first inorganic insulating particles and the second inorganic insulating particles The surface of the particles had functional groups based on the silane coupling agent and dispersant shown in Table 2.

  An adhesive tape was applied so as to sandwich the skeleton of the first insulating layer and the copper foil, and the peel strength when the adhesive tape was peeled off was measured with an autograph. The pressure-sensitive adhesive tape was peeled off so that the pressure-sensitive adhesive tape on the skeleton side of the first insulating layer carried a part of the inorganic insulating particles constituting the skeleton. The results are shown in Table 2.

  From Table 2, when the surfaces of the first and second inorganic insulating particles have the same functional group, the bonding strength between the first and second inorganic insulating particles is improved, and the strength of the skeleton of the first insulating layer is increased. I understand that. Further, it can be seen that the strength of the skeleton of the first insulating layer is greater in the case of having the functional group by the silane coupling agent and the dispersant than in the case of Example 1 having the functional group by the silane coupling agent.

DESCRIPTION OF SYMBOLS 1 Insulating sheet 2 Sheet member 3 Insulating layer 4 1st insulating layer 5 2nd insulating layer 6 Inorganic insulating particle 7 Gap | interval 8 1st resin part 11 1st inorganic insulating particle 12 2nd inorganic insulating particle 13 2nd resin part 14 Wiring board

Claims (5)

  An insulating sheet comprising a sheet member and a first insulating layer disposed on the sheet member, wherein the first insulating layer includes a plurality of inorganic insulating particles bonded to each other and the plurality of inorganic insulating layers. A plurality of inorganic insulating particles, the first inorganic insulating particles having a particle size of 5 to 80 nm, and the second inorganic particles having a particle size of 0.1 to 5 μm. An insulating sheet comprising inorganic insulating particles and having the same functional group on the surface of the first inorganic insulating particle and the surface of the second inorganic insulating particle.   2. The insulating sheet according to claim 1, wherein the first resin portion includes the same functional group as the functional group attached to a surface of the first inorganic insulating particle and a surface of the second inorganic insulating particle.   The main surface opposite to the main surface on the sheet member side of the first insulating layer further includes a second insulating layer having at least a second resin portion, and the first resin portion and the second resin portion Are formed of the same resin material, and the content of inorganic insulating particles in the first insulating layer is larger than the content of inorganic insulating particles in the second insulating layer. Insulation sheet.   A wiring board comprising a first insulating layer, a second insulating layer disposed on the first insulating layer, and a conductive layer disposed on the second insulating layer, wherein the first insulating layer Has a plurality of inorganic insulating particles bonded to each other and a first resin portion disposed between the plurality of inorganic insulating particles, and the plurality of inorganic insulating particles have a particle size of 5 A first inorganic insulating particle having a diameter of ˜80 nm and a second inorganic insulating particle having a particle diameter of 0.1 to 5 μm, the same functional group on the surface of the first inorganic insulating particle and the surface of the second inorganic insulating particle A wiring board comprising:   A mounting structure comprising: the wiring board according to claim 4; and an electronic component mounted on the wiring board and electrically connected to the conductive layer.

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