JP6633390B2 - Resin substrate, mounting structure and sheet for resin substrate - Google Patents

Description

  The present invention relates to a resin substrate, a mounting structure, and a resin substrate sheet.

  2. Description of the Related Art Conventionally, as a mounting structure in electronic devices (for example, various audiovisual devices, home appliances, communication devices, computer devices, and peripheral devices thereof), a structure in which electronic components are mounted on a wiring board has been used. As a sheet for a resin substrate for forming such a wiring board, a first inorganic insulating particle having a particle size of 3 nm or more and 110 nm or less and a second inorganic insulating particle having a particle size of 0.5 μm or more and 5 μm or less are formed on a sheet member. An inorganic insulating layer containing particles is formed (see Patent Document 1). Patent Document 1 describes that the first inorganic insulating particles adhere to each other, the second inorganic insulating particles adhere to each other via the first inorganic insulating particles, and have a skeleton of a three-dimensional network structure. A resin is disposed between the first inorganic insulating particles and between the second inorganic insulating particles and the first inorganic insulating particles.

International Publication No. 2011/037260

  In the wiring board of Patent Literature 1, although a resin is disposed between the first inorganic insulating particles and between the second inorganic insulating particles and the first inorganic insulating particles, the coupling force between the first inorganic insulating particles by the resin, The connection strength between the second inorganic insulating particles and the first inorganic insulating particles was low.

  The present invention provides a resin substrate, a mounting structure, and a resin substrate sheet capable of firmly connecting inorganic insulating particles to each other.

The resin substrate of the present invention is a resin substrate having an insulating layer, wherein the insulating layer includes a plurality of first inorganic insulating particles, a plurality of second inorganic insulating particles, and a two-surface grain boundary. And a multi-point grain boundary, wherein the second inorganic insulating particles have a smaller particle size than the first inorganic insulating particles, and the two-plane grain boundaries are formed by two adjacent first and second inorganic insulating particles . A region between the inorganic insulating particles , wherein the multipoint grain boundary is a plurality of the first inorganic insulating particles and a plurality of the second inorganic particles located at the grain boundary between the two surfaces when the insulating layer is viewed in a plan view. 2 is a region surrounded by the inorganic insulating particles , wherein the first inorganic insulating particles have a layered skeleton joined together via the second inorganic insulating particles, and a resin is formed at the multipoint grain boundary of the layered skeleton. Are arranged.

  Further, a mounting structure according to the present invention includes the resin substrate described above, and an electronic component mounted on the resin substrate and electrically connected to the wiring layer.

Further, the resin substrate sheet of the present invention is a resin substrate sheet having an insulating layer precursor on a sheet member, wherein the insulating layer precursor is a plurality of first inorganic insulating particles arranged in a plane direction, A plurality of second inorganic insulating particles, a grain boundary between two surfaces, and a multipoint grain boundary, wherein the second inorganic insulating particles have a smaller particle size than the first inorganic insulating particles; The inter-surface grain boundary is a region between two adjacent first inorganic insulating particles , and the multipoint grain boundary is a surface of the four first inorganic insulating particles when the insulating layer is viewed in plan. And a region surrounded by the plurality of second inorganic insulating particles located at the grain boundary between the two surfaces, and a layered skeleton in which the first inorganic insulating particles are bonded to each other via the second inorganic insulating particles. And a resin is disposed at the multipoint grain boundary of the layered skeleton.

  According to the resin substrate of the present invention, the inorganic insulating particles can be strongly connected to each other.

FIG. 1A is a cross-sectional view schematically showing a resin substrate sheet according to an embodiment of the present invention, and FIG. 1B is an enlarged view thereof. (A) is a cross-sectional view along line 2a-2a in FIG. 1, (b) is a vertical cross-sectional view along line 2b-2b in (a), and (c) is a first cross-sectional view. It is a longitudinal cross-sectional view of the 1st insulating layer precursor which has a resin layer on the upper and lower surfaces of inorganic insulating particles. It is explanatory drawing which shows the process of forming a 1st insulating layer precursor on a sheet member. (A) is a cross-sectional view schematically showing a resin substrate sheet according to another embodiment of the present invention, (b) is an enlarged view thereof, and (c) is a cross-section taken along line 4c-4c of (b). FIG. FIG. 5 is an explanatory view showing a step of forming a first insulating layer precursor of FIG. 4 on a sheet member. (A) is sectional drawing which showed the outline of the sheet | seat for resin boards which concerns on another form of this invention, (b) is the enlarged view, (c) is 6c-6c line | wire of (b). (D) is a cross-sectional view showing a state in which the first inorganic insulating particles of the upper and lower layered skeletons are arranged in a closely packed shape. FIG. 7 is an explanatory view showing a step of forming a first insulating layer precursor of FIG. 6 on a sheet member. FIG. 1 is a cross-sectional view schematically illustrating a resin substrate according to an embodiment of the present invention. FIG. 9 is a cross-sectional view illustrating one step of a method for manufacturing the wiring board of FIG. 8. FIG. 9 is a cross-sectional view illustrating one step of a method for manufacturing the wiring board of FIG. 8. FIG. 9 is a cross-sectional view illustrating one step of a method for manufacturing the wiring board of FIG. 8. FIG. 9 is a cross-sectional view illustrating one step of a method for manufacturing the wiring board of FIG. 8.

(Form 1)
Hereinafter, a resin substrate sheet according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. It should be noted that the present invention is not limited to the following embodiments, and various changes, improvements, and the like can be made without departing from the gist of the present invention.

  FIG. 1 schematically shows a cross section of the resin substrate sheet 1 cut in the vertical direction (the thickness direction of the resin substrate sheet). The resin substrate sheet 1 is used for manufacturing a resin substrate, for example, as described later. As shown in FIG. 1, the resin substrate sheet 1 includes a sheet member 2 and an insulating layer precursor (hereinafter, may be simply referred to as an insulating layer) 3 laminated on the main surface of the sheet member 2. Have.

  The sheet member 2 supports the insulating layer 3 when handling the insulating sheet 1, and is processed into wiring. The sheet member 2 is made of, for example, a flat copper foil. When the sheet member 2 is made of copper foil, the heat resistance of the sheet member 2 can be improved, and it can be used as a wiring layer described later. Note that the sheet member 2 may be a film-shaped resin sheet.

  The insulating layer 3 secures insulation between wiring layers of the resin substrate described later. The insulating layer 3 includes a first insulating layer precursor (hereinafter, may be simply referred to as a first insulating layer) 4 laminated on the sheet member 2 and a second insulating layer precursor laminated on the first insulating layer 4. (Hereinafter, simply referred to as a second insulating layer) 5. The thickness of the insulating layer 3 is set to, for example, 5 μm or more and 50 μm or less, preferably 8 μm or more and 20 μm or less. The thickness of the first insulating layer 4 is set, for example, to 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 part 8. That is, the plurality of inorganic insulating particles 6 are connected to each other while maintaining the particle shape, thereby forming the layered skeleton A, which is the main part of the first insulating layer 4.

  More specifically, the first insulating layer 4 includes a plurality of first inorganic insulating particles 6a arranged in the surface direction (two-dimensional) of the sheet member 2 and two adjacent first inorganic insulating particles 6a. And a multipoint grain boundary 7b formed between three or more (four in FIG. 2) first inorganic insulating particles 6a adjacent to each other. A plurality of second inorganic insulating particles 6b smaller than the first inorganic insulating particles 6a were arranged at the grain boundary 7a, and two first inorganic insulating particles 6a were joined via the plurality of second inorganic insulating particles 6b. An uncured or semi-cured resin is disposed at a multipoint grain boundary 7b of the layered skeleton A to form a first resin portion 8, and a first insulating layer 4 is formed. ing. In FIG. 1, the first insulating layer 4 has a single layered skeleton A.

  That is, when the first insulating layer 4 is viewed in a plan view, as shown in FIG. 2A, the distance between the opposing first inorganic insulating particles (hereinafter, sometimes referred to as first particles) 6a is two. A large number of second inorganic insulating particles (hereinafter, sometimes referred to as “second particles”) 6b are arranged in the intergranular boundary 7a, and the second particles 6b are connected to each other. The first particles 6a are joined, and the two first particles 6a are joined via the joined second particles 6b.

  When the first insulating layer 4 is viewed in a plan view and in a cross-sectional view, the second particles 6b are arranged around a portion where the two first particles 6a are closest to each other, as shown in FIG. As described above, the first insulating layer 4 is located at the center in the thickness direction, and does not exist in the upper and lower layers of the first insulating layer 4 in the thickness direction. The second particles 6b are connected to each other, and are also connected to the first particles 6a and the second particles 6b.

  Further, as shown in FIG. 2A, the multipoint grain boundary 7b is surrounded by the surface of the four first particles 6a and a large number of second particles 6b of the two-surface grain boundary 7a when viewed in a plan view. The uncured or semi-cured resin is disposed in the multipoint grain boundary 7b, and the first resin portion 8 is formed. As shown in FIG. 2B, this resin is disposed not only in the central portion in the thickness direction of the first insulating layer 4 but also in the upper layer portion and the lower layer portion. Although not shown, a resin is also provided between the second particles 6b. The second particles 6b are connected to each other by a neck, and the second particles 6b have a three-dimensional network structure, and a resin is disposed at the grain boundaries.

  Further, the content of the resin (first resin portion 8) in the layered skeleton A is set to, for example, 55% by volume or more, preferably 60% by volume or more. The content of such a resin can be obtained, for example, by using a micrograph of a cross section of the first insulating layer 4 to calculate an area ratio by an image analyzer and converting the area ratio.

  The thickness of the first insulating layer 4 is the same as the diameter of the first particles 6a in FIG. 2B, but as shown in FIG. 2C, the thickness of the layered skeleton A (the first particles 6a (Diameter of the first particle 6a), and may have a resin layer on the upper and lower surfaces of the first particle 6a. In other words, the first insulating layer 4 may have a resin layer on the upper and lower surfaces of the layered skeleton A. Note that, naturally, the first insulating layer 4 may have a resin layer on either the upper surface or the lower surface of the layered skeleton A.

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

  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. Further, the inorganic insulating particles 6 may be made of a single material, or may be made of 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, 0.6 ppm / ° C. or more and 12 ppm / ° C. or less. 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. It is particularly desirable that the inorganic insulating particles 6 are fused silica.

  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 appropriately contains an inorganic filler described below. May be. The first resin portion 8 is made of a material having a coefficient of thermal expansion of, for example, 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 in an uncured or semi-cured state in the resin substrate insulating sheet 1.

  The second insulating layer 5 is for bonding the insulating layer 3 and a wiring layer, or the insulating layer 3 and another insulating layer 3 laminated on the insulating layer 3 at the time of manufacturing the resin substrate. As shown in FIG. 1B, the second insulating layer 5 has a second resin part 13 and an inorganic filler 35 disposed in the resin of the second resin part 13. The second insulating layer 5 may be formed by applying a large amount of resin on the layered skeleton A in the step of distributing the resin to the multipoint grain boundaries 7b.

  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 second insulating layer 5 is reduced, and the first insulating layer 4 can effectively reduce the amount of thermal expansion of the second insulating layer 5. The thickness of the second insulating layer 5 is set, for example, to 1 μm or more and 40 μm or less.

  The second resin portion 13 of the second insulating layer 5 is connected to 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, separation due to a difference in the coefficient of thermal expansion between the first insulating layer 4 and the second insulating layer 5 can be reduced. it can.

  Further, 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 as described above. That is, the resin forming the second insulating layer 5 may enter the multi-point grain boundaries 7 b of the first insulating layer 4 and between the second particles 6 b to form the first resin portion 8. As a result, the separation between the second insulating layer 5 and the first insulating layer 4 can be effectively reduced.

  The second resin portion 13 mainly forms 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, and contains an inorganic filler 35 described below as appropriate. You may do it. The second resin portion 13 is made of a material having a coefficient of thermal expansion 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 size of the inorganic filler 35 may be equal to or larger than the particle size of the first particles 6a. The particle diameter of the inorganic filler 35 is set, for example, to 0.1 μm or more and 5 μm or less. Further, the content of the inorganic filler 35 in the second insulating layer 5 may be smaller than the content of the inorganic insulating particles 6 in the first insulating layer 4. The content of the inorganic filler 35 in the second insulating layer 5 is set to, for example, 60% by volume or less. The inorganic filler 35 of the second insulating layer 5 exists separately in the resin.

  A method for manufacturing the resin substrate sheet will be described. First, as disclosed in Japanese Patent Application Laid-Open No. 2010-64945, for example, the first particles 6a and the second particles 6b are positively and negatively charged, and the second particles 6a and 6b are charged on the surface of the first particles 6a by electrostatic interaction. The particles 6b are adsorbed. The second particles 6b do not fall off but adhere to the surface of the first particles 6a with such an attractive force that they can move.

  Thereafter, the first particles 6a to which the second particles 6b are adsorbed are dispersed in a dispersion such as water, and the dispersion is applied on the sheet member 2 and dried. In this drying step, the second particles 6b move to the grain boundary 7a between the two surfaces of the first particles 6a together with the water by surface tension, and the dispersion is completely removed. Although the subsequent sintering step is unnecessary, sintering may be performed at a very low temperature. Through the above steps, a layered skeleton A can be formed on the sheet member 2 as shown in FIG. 3A (for example, see the latest application and prospect of the sol-gel method published by CMC P250-251).

  Then, as shown in FIG. 3B, a resin 8a for forming the second insulating layer 5 is applied to the layered skeleton A and pressed, so that the resin 8a is multiplied as shown in FIG. In addition to being arranged at the important grain boundary 7b, it is arranged between each second particle 6b and between the first particle 6a and the second particle 6b of the two-plane grain boundary 7a.

  Specifically, the sheet member 2, the layered skeleton A of the first insulating layer 4 and the resin 8a are heated and pressed in the vertical direction, so that the second insulating layer 5 is formed on the multipoint grain boundaries 7b and the like of the first insulating layer 4. The resin 8a to be formed is introduced.

  The heating temperature of the sheet member 2 and the like is set to, for example, 60 ° C. or more and 250 ° C. or less. The pressure applied to the sheet member 2 and the like is set to, for example, 0.1 MPa or more and 5 MPa or less. The heating and pressing time of the sheet member 2 and the like is set to, for example, 0.5 minute or more and 300 minutes or less. The melt viscosity of the resin 8a of the second insulating layer 5 during the heating time is set, for example, to 10,000 Pa · s or less. By appropriately adjusting the thickness of the layered skeleton A, the pressure applied to the sheet member 2 and the like, and the melt viscosity of the resin 8a of the second insulating layer 5, the resin 8a (the The 1 resin portion 8) can be brought into contact with the sheet member 2.

  Alternatively, by preparing a sheet of the above-mentioned resin 8a formed on a carrier film by an existing forming method, placing it on the layered skeleton A, and applying heat and pressure in the same manner as described above, The resin 8a can enter the multipoint grain boundaries 7b and the like of the first insulating layer 4. Note that the carrier film is peeled off after heating and pressing. The first resin portion 8 of the first insulating layer 4 in the resin substrate sheet 1 is in an uncured or semi-cured state. Further, the resin 8a is not limited to the resin forming the second insulating layer 5.

  Thereafter, the resin for forming the second insulating layer 5 is applied and dried on the first insulating layer 4 to form the second insulating layer 5 and the resin substrate sheet 1 can be manufactured.

  In addition, the resin 8a forming the second insulating layer 5 is arranged in a large amount on the layered skeleton A, and the first insulating layer 4 and the second insulating layer 5 are simultaneously formed by heating and pressing in the same manner as described above. It may be formed.

  In the resin substrate sheet 1 described above, the plurality of first and second particles 6a and 6b are partially bonded to each other while maintaining the particle shape, and the first particles 6a can be strongly connected to each other. Since the first resin portion 8 is disposed at the multipoint grain boundary 7b, the amount of resin in the first insulating layer 4 can be increased as compared with the conventional case, and the coupling force between the first particles 6a by the first resin portion 8 is improved. it can.

  Further, since the first resin portion 8 filled in the multipoint grain boundary 7b is bonded to the surface of the sheet member 2, in other words, the first resin portion 8 is arranged between the plurality of first particles 6a. In addition, since the surfaces of the plurality of first particles 6a are joined to one main surface of the sheet member 2, the first resin portion is formed on the sheet member 2 at the stage of the resin substrate sheet 1 before the production of the resin substrate. The contact strength between the sheet member 2 and the first insulating layer 4 can be improved by bringing the sheet member 8 into contact. As a result, peeling of the first insulating layer 4 from the sheet member 2 is reduced, and handling of the resin substrate sheet 1 can be facilitated.

(Form 2)
FIG. 4 shows another embodiment of the resin substrate sheet 1 of the present invention, in which the first insulating layer 4 is composed of a two-layered skeleton A. In the resin substrate sheet 1 of this embodiment, the first insulating layer 4 is formed by laminating the layered skeleton A of the embodiment 1 in two layers in the vertical direction, and the first particles 6a of the upper layered skeleton A1 and the lower layer And the first particles 6a of the layered skeleton A2 are arranged in the thickness direction of the layered skeletons A1 and A2.

  Specifically, a line S1 connecting the center of the first particle 6a of the layered skeleton A1 and the center of the first particle 6a of the layered skeleton A2 is a line connecting the centers of the plurality of first particles 6a of the layered skeleton A1. The first particles 6a arranged in the X and Y directions of the upper layered skeleton A1 and the first particles 6a arranged in the X and Y directions of the lower layered skeleton A2 so that the component S2 is substantially orthogonal to the upper layered skeleton A1. They are arranged in the thickness direction of the layered skeletons A1 and A2. In other words, when viewed in a plan view in the thickness direction of the layered skeletons A1 and A2, the first particles 6a of the layered skeletons A1 and A2 appear to be substantially overlapped as shown in FIG. A resin is disposed at the multipoint grain boundaries 7b of the layered skeletons A1 and A2, and a resin is provided between the second particles 6b and between the first particles 6a and the second particles 6b of the two-plane grain boundaries 7a. The first resin portion 8 is formed.

  In the resin substrate sheet 1 having such a configuration, the layered skeletons A1 and A2 are respectively formed on the sheet member 2 in the same manner as in the manufacturing method of the first aspect, and the resin skeleton is formed on the multipoint grain boundaries 7b of the layered skeletons A1 and A2. After that, as shown in FIGS. 5A and 5B, the layered skeleton A1 is laminated on the layered skeleton A2, and as shown in FIG. 5C, the sheet member on the layered skeleton A1 2 can be manufactured by peeling off the first insulating layer 4 and forming the second insulating layer 5 on the second insulating layer 4.

  The resin substrate sheet 1 shown in FIG. 4 can have the same effect as the first embodiment, but can further improve the strength of the first insulating layer 4.

(Form 3)
FIG. 6 shows still another embodiment of the resin substrate sheet 1 of the present invention, in which the first insulating layer 4 is constituted by a two-layered skeleton A. In the resin substrate sheet 1 of this embodiment, the first insulating layer 4 is formed by laminating the layered skeleton A of the embodiment 1 in two layers in the vertical direction, and the first particles 6a of the upper layered skeleton A1 are arranged on the lower side Are located between the first particles 6a of the layered skeleton A2.

  Specifically, as shown in FIGS. 6B and 6C, a line segment S3 connecting the center of the first particle 6a of the layered skeleton A1 and the center of the first particle 6a of the layered skeleton A2 is a layered skeleton. The first particles 6a of the upper layered skeleton A1 and the first particles 6a of the lower layered skeleton A2 are arranged such that a line segment S4 connecting the centers of the plurality of first particles 6a of A1 is approximately 45 degrees. They are arranged. The resin is arranged at the multipoint grain boundaries 7b of the layered skeletons A1 and A2, and the resin is arranged between the second particles 6b of the two-plane grain boundaries 7a and between the first particles 6a and the second particles 6b. Thus, a first resin portion 8 is formed.

  In the resin substrate sheet 1 having such a configuration, the layered skeletons A1 and A2 are respectively formed on the sheet member 2 in the same manner as in the manufacturing method of the first aspect, and the resin skeletons A1 and A2 are formed on the multipoint grain boundaries 7b and the like. Then, as shown in FIGS. 7A and 7B, the first particles 6a of the upper layered skeleton A1 are located between the first particles 6a of the lower layered skeleton A2. The layered skeleton A1 is laminated on the layered skeleton A2, and the sheet member 2 on the layered skeleton A1 is peeled off as shown in FIG. 7 (c), whereby the resin as shown in FIGS. A sheet for a substrate can be manufactured.

  The resin substrate sheet 1 of FIG. 6 can also have the same effect as in the first embodiment, but can further improve the strength of the first insulating layer 4 as compared with the first and second embodiments.

  Further, as shown in FIG. 6 (d), the first particles 6a of the upper layered skeleton A1 are closely packed between the first particles 6a of the lower layered skeleton A2. By laminating the layered skeleton A1 thereon, the strength of the first insulating layer 4 can be further improved.

(Resin substrate)
Next, the resin substrate 14 manufactured using the resin substrate sheet 1 described above will be described in detail with reference to FIG. FIG. 8 schematically shows a cross section of the resin substrate cut in the vertical direction.

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

  The core substrate 15 is intended to increase the rigidity of the resin substrate 14 and attain conduction between the pair of build-up layers 16. The core substrate 15 includes a resin base 17, a cylindrical through-hole conductor 18 formed vertically penetrating the resin base 17, and a columnar insulator disposed in a region surrounded by the through-hole conductor 18. 19.

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

  The resin contained in the resin base 17 forms a main part of the resin base 17. This resin includes, for example, an epoxy resin, a bismaleimide triazine resin, a cyanate resin, a polyparaphenylene benzobisoxazole resin, a wholly aromatic polyamide resin, a polyimide resin, an aromatic liquid crystal polyester resin, a polyetheretherketone resin or a polyetherketone resin. Of resin material.

  The base material included in the resin base 17 increases the rigidity and lowers the thermal expansion of the resin base 17. The substrate is made of a woven or non-woven fabric made of fibers or fibers arranged in one direction. The fibers are made of, for example, glass fibers or resin fibers.

  The inorganic insulating filler contained in the resin base 17 increases the rigidity and lowers the thermal expansion of the resin base 17. This 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 electrically connects the upper and lower wiring layers 21 of the core substrate 15. This 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 a resin material such as a polyimide resin, an acrylic resin, an epoxy resin, a cyanate resin, a fluorine resin, a silicon resin, a polyphenylene ether resin, or a bismaleimide triazine resin.

  The through-hole may be filled with a conductive material similar to the above-described through-hole conductor instead of the insulator 19.

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

  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 resin substrate sheet 1 described above. In the resin substrate sheet 1, the first resin portion 8 of the first insulating layer 4 and the second resin portion 13 of the second insulating layer 5 were not cured, but in the resin substrate 14, the first resin portion 8 and the The second resin portion 13 is hardened.

  The second insulating layer 5 is for bonding the resin base 17 and the insulating layer 3 or bonding the laminated insulating layers 3 while bonding to the side and top surfaces of the wiring layer 21. The first insulating layer 4 forms a main part of the insulating layer 3 and functions as an insulating member between the wiring layers 21 arranged apart from each other along the thickness direction. Since the first insulating layer 4 has a low coefficient of thermal expansion and high rigidity as compared with the resin material, the coefficient of thermal expansion of the insulating layer 3 in the plane direction can be reduced. Therefore, the difference in the coefficient of thermal expansion in the planar direction between the resin substrate 14 and an electronic component (not shown) mounted on the resin substrate 14 can be reduced, and the warpage of the resin substrate 14 can be reduced.

  The wiring layers 21 are arranged apart from each other along the plane direction or the thickness direction, and function as ground wiring, power supply wiring, or signal wiring. This wiring layer 21 is made of a conductive material such as copper, silver, gold, aluminum, nickel or chromium. The thickness of the wiring layer 21 is set, for example, to 3 μm or more and 20 μm or less. The coefficient of thermal expansion of the wiring layer 21 is set, for example, to 14 ppm / ° C. or more and 18 ppm / ° C. or less. The L / S (line / space) of the wiring layer 21 is set to, for example, 3/3 μm or more and 60/60 μm or less.

  The via conductor 20 is for electrically connecting the wiring layers 21 arranged apart from each other in the thickness direction, and is formed in a columnar shape narrowing toward the core substrate 15. The via conductor 20 is made of, for example, a conductive material of copper, silver, gold, aluminum, nickel, or chromium. Further, the thermal expansion coefficient of the via conductor 20 is set to, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less.

  A method for manufacturing the resin substrate 14 according to the embodiment of the present invention will be described with reference to FIGS. The method for manufacturing the resin substrate 14 mainly includes a preparing step, a laminating step, an exposing step, and a wiring forming step. It should be noted that the present invention is not limited to the following embodiments, and various changes, improvements, and the like can be made without departing from the gist of the present invention. 9 to 12 are cross-sectional views showing one process of a method of manufacturing the resin substrate 14 using the resin substrate sheet 1 according to one embodiment of the present invention.

  (1) First, the resin substrate sheet 1 manufactured as described above is prepared.

  (2) Prepare a core substrate 15 (substrate). In manufacturing the core substrate 15, first, a resin base 17 in which a plurality of resin layers are laminated on a metal foil, for example, is formed. Next, after forming a through hole in the resin base 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 applied to an 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.

  (3) As shown in FIG. 9, the resin substrate sheet 1 is laminated on the upper and lower surfaces of the core substrate 15. Specifically, the lamination of the resin substrate sheet 1 is performed such that the second insulating layer 5 of the resin substrate sheet 1 contacts the core substrate 15.

  (4) The first resin portion 8 and the second resin portion 13 are thermoset. Specifically, by heating the resin substrate sheet 1 and the core substrate 15 to a temperature equal to or higher than the thermosetting start temperature of the first resin portion 8 and the second resin portion 13 while applying pressure, the resin substrate sheet 1 The uncured first resin portion 8 and second resin portion 13 are thermally cured. The pressure of the resin substrate sheet 1 and the like is set to, for example, 0.5 MPa or more and 5.0 MPa or less, and the heating temperature is set to 80 ° C. or more and 250 ° C. or less, for example.

  (5) As shown in FIG. 10, a through hole is formed from the surface of the sheet member 2 to penetrate the sheet member 2, the first insulating layer 4, and the second insulating layer 5 in the thickness direction. The through holes are formed by irradiating the upper surface of the sheet member 2 with laser light using, for example, a YAG laser device or a carbon dioxide laser device.

  (6) A so-called desmear treatment is performed to remove the resin residue remaining at the bottom of the through hole. The desmear treatment is generally performed using a strong alkaline aqueous solution, but plasma or the like may be used. The strong alkaline aqueous solution is, for example, an aqueous solution of potassium permanganate or sodium permanganate.

  (7) 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.

  (8) The wiring layer 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, as shown in FIG.

  When the surface of the insulating layer 3 is roughened, after (8), a part of the surface layer of the first insulating layer 4 (inorganic insulating particles) exposed by removing a part of the sheet member 2 by etching. 6) and the surface of the insulating layer 3 can be roughened. For example, when the inorganic insulating particles 6 are made of silicon oxide, the removal of a part of the surface of the first insulating layer 4 is performed using a strong alkaline aqueous solution that dissolves the inorganic insulating particles 6. It is an aqueous solution of potassium permanganate or sodium permanganate. Since a part of the inorganic insulating particles 6 of the first insulating layer 4 is removed while the second insulating layer 5 remains, the second insulating layer 5 is formed of a material that is hardly soluble in the aqueous solution. 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 a different single material such as aluminum oxide into the plurality of inorganic insulating particles 6.

  (9) Next, as shown in FIG. 12, in order to form a plurality of insulating layers 3, the surface of the first insulating layer 4 whose surface has been roughened and the surface of the wiring layer 21 are further coated with a resin. The uncured second insulating layer 5 of the substrate sheet 1 is laminated, and a plurality of insulating layers 3 are formed. The uncured second insulating layer 5 can be firmly joined to the roughened surface of the first insulating layer 4 by the anchor effect. 9 to 12 show the insulating sheet 1 in an enlarged manner for easy understanding. As described above, the resin substrate 14 as shown in FIG. 8 is manufactured.

  Such a resin substrate 14 has the following effects as compared with Patent Document 1 described above. That is, in Patent Document 1, since the filling rate of the inorganic insulating particles in the insulating layer can be higher than that of the so-called close-packing, the thermal expansion coefficient and the thermal conductivity can be appropriately selected by the inorganic insulating particles. It is possible to control such thermal characteristics, mechanical characteristics such as elastic modulus, dielectric characteristics and insulation. On the other hand, as a result of a decrease in the content of the resin, the risk of cracks or the like being generated due to a decrease in flexibility when the wiring board is formed is increased, and the embedding property of the wiring pattern is deteriorated. When fused silica is selected as the inorganic insulating particles for the purpose of reducing substrate warpage due to compatibility of rigidity, a strong alkali treatment generally used in the resin residue removal step after laser processing (so-called desmear step) In this case, the first inorganic insulating particles are very fine, so that the first inorganic insulating particles dissolve in a short time and the insulating layer collapses.

  On the other hand, in the resin substrate 14 of the above-described embodiment, the plurality of first and second particles 6a and 6b are partially connected to each other while maintaining the particle shape, and the first particles 6a are strongly connected to each other. In addition, since the first resin portion 8 is arranged at the multipoint grain boundary 7b, the amount of resin in the first insulating layer 4 can be increased as compared with the conventional case, and the first particles 6a are connected to each other by the first resin portion 8. Power can be improved.

  In addition, compared to Patent Document 1, without increasing the filling ratio of the first and second particles 6a and 6b in the insulating layer excessively, in other words, without excessively reducing the resin content, Since it is possible to control the characteristics, particularly to improve the mechanical characteristics, it is possible to prevent the occurrence of cracks and the like, the deterioration of the pattern embedding property, the collapse of the first insulating layer 4 in the desmear process, and the like.

  The mounting structure is obtained by disposing an electronic component on the upper surface of the resin substrate 14 and mounting the electronic component on the wiring layer 21 via a bonding member such as a bump or solder.

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

  In the above-described embodiment of the present invention, the configuration in which two insulating layers 3 are stacked has been described as an example. However, one or three or more insulating layers may be used.

  Further, in the embodiment of the present invention described above, the configuration in which the build-up multilayer wiring board is manufactured using the resin substrate sheet 1 is described as an example. It doesn't matter. As another resin substrate, for example, an interposer substrate, a coreless substrate, or a single-layer substrate may be used. Here, the interposer substrate includes one insulating layer 3, a through conductor penetrating the insulating layer 3, and a wiring 21 disposed on the insulating layer 3 and electrically connected to the through conductor. It is a resin substrate. The coreless substrate includes the insulating layer 3, a via conductor 20 penetrating the insulating layer 3, and a wiring 21 disposed on the insulating layer 3 and electrically connected to the via conductor 20. It is a resin substrate in which a plurality of wirings 21 are alternately laminated, and does not have the core substrate 15.

Furthermore, in the above embodiment, the case where the first and second particles 6a and 6b are included in the first insulating layer 4 has been described, but inorganic insulating particles other than the first and second particles 6a and 6b may be included. .

REFERENCE SIGNS LIST 1 resin substrate sheet 2 sheet member 3 insulating layer 4 first insulating layer 5 second insulating layer 6a first inorganic insulating particles (first particles)
6b Second inorganic insulating particles (second particles)
Reference numeral 7a A grain boundary between two surfaces 7b A multi-point grain boundary 8 First resin portion 13 Second resin portion 14 Resin substrate 21 Wiring layer A Layered skeleton

Claims (6)

A resin substrate having an insulating layer, wherein the insulating layer includes a plurality of first inorganic insulating particles arranged in a plane direction, a plurality of second inorganic insulating particles, an inter-surface grain boundary, and a multipoint grain boundary. Has,
The second inorganic insulating particles have a smaller particle size than the first inorganic insulating particles,
The inter-plane grain boundary is a region between two adjacent first inorganic insulating particles ,
The multipoint grain boundary is surrounded by four surfaces of the first inorganic insulating particles and a plurality of the second inorganic insulating particles located at the grain boundary between the two surfaces when the insulating layer is viewed in plan. Area,
A resin substrate, wherein the first inorganic insulating particles have a layered skeleton joined together via the second inorganic insulating particles, and a resin is disposed at the multiple-point grain boundary of the layered skeleton.   The insulating layer has a plurality of the layered skeletons in a vertical direction, and the first inorganic insulating particles of the upper layered skeleton and the first inorganic insulating particles of the lower layered skeleton are arranged in the thickness direction of the layered skeleton. The resin substrate according to claim 1, wherein the resin substrates are arranged.   The insulating layer has a plurality of the layered skeletons in a vertical direction, and the first inorganic insulating particles of the upper layered skeleton are located between the first inorganic insulating particles of the lower layered skeleton. The resin substrate according to claim 1, wherein A resin substrate according to any one of claims 1 to 3, characterized in that it comprises the insulating layer, and a wiring layer disposed on the insulating layer. A mounting structure comprising: the resin substrate according to claim 4 ; and an electronic component mounted on the resin substrate and electrically connected to the wiring layer. A resin substrate sheet having an insulating layer precursor on a sheet member,
The insulating layer precursor has a plurality of first inorganic insulating particles arranged in a plane direction, a plurality of second inorganic insulating particles, a grain boundary between two faces, and a multipoint grain boundary,
The second inorganic insulating particles have a smaller particle size than the first inorganic insulating particles,
The inter-plane grain boundary is a region between two adjacent first inorganic insulating particles ,
The multipoint grain boundary is surrounded by four surfaces of the first inorganic insulating particles and a plurality of the second inorganic insulating particles located at the grain boundary between the two surfaces when the insulating layer is viewed in plan. Area,
A resin substrate, wherein the first inorganic insulating particles have a layered skeleton joined together via the second inorganic insulating particles, and a resin is disposed at the multipoint grain boundary of the layered skeleton. Sheet.

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