JP2015012082A - Wiring board and mounting structure using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board excellent in electrical reliability and a mounting structure thereof.SOLUTION: A wiring board 3 according to one embodiment of the present invention includes: an inorganic insulating layer 14 which has a plurality of protrusions 26 and a plurality of recesses 27 positioned between the protrusions 26 on one main surface; and a conductive layer 11 which is partially arranged on the one main surface of the inorganic insulating layer 14 and has recessed portions 28 corresponding to the protrusions 26 and protruding portions 29 corresponding to the recesses 27. The inorganic insulating layer 14 includes: a plurality of first inorganic insulating particles 22 some of which are connected to each other; and a first resin part 18 which is interposed between the plurality of first inorganic insulating particles 22 and the conductive layer 11 on the one main surface of the inorganic insulating layer 14.

Description

  The present invention relates to a wiring board used for electronic devices (for example, various audiovisual devices, home appliances, communication devices, computer devices and peripheral devices thereof) and a mounting structure using the same.

  Conventionally, a mounting structure in which an electronic component is mounted on a wiring board is used in an electronic device.

  As this wiring board, for example, Patent Document 1 discloses a ceramic layer (inorganic insulating layer), a conductor pattern (conductive layer) disposed on a part of the main surface of the ceramic layer, and other parts of the ceramic layer. A composite multilayer board (wiring board) provided with an arranged resin layer is described.

  By the way, when a stress is applied to the wiring board, the stress is applied between the inorganic insulating layer and the conductive layer, and the inorganic insulating layer and the conductive layer may be separated. As a result, the wiring is disconnected, and the electrical reliability of the wiring board is likely to be lowered.

  Therefore, it is desired to provide a wiring board having excellent electrical reliability.

JP 2005-223226 A

  The present invention solves the above-described requirements by providing a wiring board having excellent electrical reliability and a mounting structure thereof.

  A wiring board according to an aspect of the present invention includes an inorganic insulating layer having a plurality of convex portions and a plurality of concave portions located between the convex portions on one main surface, and a portion of the inorganic insulating layer on the one main surface. And a conductive layer having a recess corresponding to the protrusion and a protrusion corresponding to the recess, and the inorganic insulating layer includes a plurality of first inorganic insulating particles partially connected to each other And a first resin portion interposed between the plurality of first inorganic insulating particles and the conductive layer on the one main surface of the inorganic insulating layer.

  A mounting structure in one embodiment of 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 wiring board in one embodiment of the present invention, the inorganic insulating layer and the conductive layer are formed by the first resin portion interposed between the plurality of first inorganic insulating particles and the conductive layer on one main surface of the inorganic insulating layer. The adhesive strength can be increased. Accordingly, it is possible to obtain a wiring board having excellent electrical reliability.

  According to the mounting structure in one embodiment of the present invention, since the wiring board described above is provided, a mounting structure having excellent electrical reliability can be obtained.

(A) is sectional drawing which cut | disconnected the mounting structure in one Embodiment of this invention in the thickness direction, (b) is sectional drawing which expanded and showed R1 part of Fig.1 (a). (A) is sectional drawing which expanded and showed R2 part of FIG.1 (b), (b) is an enlarged view of the cross section along the main surface direction of the inorganic insulating layer of FIG.1 (b). is there. (A) And (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a), (c) is the cross section which expanded and showed R3 part of FIG.3 (b) FIG. (A) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a), (b) is sectional drawing which expanded and showed R4 part of Fig.4 (a), (C) is an enlarged cross-sectional view of a portion R5 in FIG. 4 (b). (A) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a), (b) is sectional drawing which expanded and showed R6 part of Fig.5 (a), (C) is an enlarged cross-sectional view of a portion R7 in FIG. 5 (b). (A) And (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a), (c) is the cross section which expanded and showed R8 part of FIG.6 (b) FIG. (A) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a), (b) is sectional drawing which expanded and showed R9 part of Fig.7 (a). (A) And (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a).

  Hereinafter, a mounting structure including a wiring board according to an embodiment of the present invention will be described in detail with reference to the drawings.

  The mounting structure 1 shown in FIG. 1A is used for electronic devices such as various audiovisual devices, home appliances, communication devices, computer devices or peripheral devices thereof. The mounting structure 1 includes an electronic component 2 and a wiring board 3 on which the electronic component 2 is mounted.

  The electronic component 2 is a semiconductor element such as an IC or LSI. The electronic component 2 is flip-chip mounted on the wiring board 3 via bumps 4 made of a conductive material such as solder. The thickness of the electronic component 2 is, for example, not less than 0.1 mm and not more than 1 mm. The coefficient of thermal expansion in each direction of the electronic component 2 is, for example, not less than 2 ppm / ° C. and not more than 7 ppm / ° C. In addition, the thermal expansion coefficient of the electronic component 2 is measured by a measuring method according to JIS K7197-1991 using a commercially available TMA (Thermo-Mechanical Analysis) apparatus. Hereinafter, the coefficient of thermal expansion of each member is measured in the same manner as the electronic component 2.

  The wiring board 3 has functions of supporting the electronic component 2 and supplying power and signals for driving or controlling the electronic component 2 to the electronic component 2. The wiring substrate 3 includes a core substrate 5 and a pair of buildup layers 6 formed on the upper and lower surfaces of the core substrate 5.

  The core substrate 5 is intended to enhance electrical connection between the pair of buildup layers 6 while increasing the rigidity of the wiring substrate 3. The core substrate 5 includes a base body 7 that supports the buildup layer 6, a cylindrical through-hole conductor 8 that is disposed in a through hole that penetrates the base body 7 in the thickness direction, and a columnar shape that is surrounded by the through-hole conductor 8. The insulator 9 is included.

  The base 7 makes the wiring board 3 highly rigid and has a low coefficient of thermal expansion. The base 7 includes, for example, a resin such as an epoxy resin, a base material such as a glass cloth coated with the resin, and filler particles made of silicon oxide or the like dispersed in the resin. The thickness of the substrate 7 is, for example, 0.04 mm or more and 2 mm or less.

  The through-hole conductor 8 electrically connects the pair of buildup layers 6 to each other. The through-hole conductor 8 can be formed of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium.

  The insulator 9 fills the space surrounded by the through-hole conductor 8. The insulator 9 can be formed of a resin material such as an epoxy resin.

  On the other hand, as described above, a pair of buildup layers 6 are formed on the upper and lower surfaces of the core substrate 5. Of the pair of buildup layers 6, one buildup layer 6 is connected to the electronic component 2 via the bumps 4, and the other buildup layer 6 is a mother board or the like via solder balls (not shown), for example. Connect with external circuit.

  The build-up layer 6 penetrates the insulating layer 10 in the thickness direction, a plurality of insulating layers 10 stacked on the substrate 7, a plurality of conductive layers 11 partially disposed on the substrate 7 or on the insulating layer 10. The plurality of via conductors 12 are included.

  The insulating layer 10 functions as an insulating member between the conductive layers 11 separated in the thickness direction or the main surface direction and an insulating member between the via conductors 12 separated in the main surface direction. Details of the insulating layer 10 will be described later.

  The conductive layers 11 are separated from each other in the thickness direction or main surface direction, and function as wiring such as ground wiring, power supply wiring, or signal wiring. The conductive layer 11 is made of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium. The thickness of the conductive layer 11 is 3 μm or more and 20 μm or less, and the coefficient of thermal expansion in the thickness direction and the main surface direction of the conductive layer 11 is, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less. The Young's modulus of the conductive layer 11 is, for example, 70 GPa or more and 150 or less GPa. In addition, the Young's modulus of the conductive layer 11 is measured by a method according to ISO14577-1: 2002 using a nanoindenter XP manufactured by MTS. Hereinafter, the Young's modulus of each member is measured in the same manner as the conductive layer 11.

  The via conductor 12 electrically connects the conductive layers 11 separated from each other in the thickness direction. The via conductor 12 is made of the same material as that of the conductive layer 11 and has the same characteristics. The via conductors 12 are formed in a columnar shape that becomes narrower toward the core substrate 5. The width of the via conductor 12 is, for example, 10 μm or more and 75 μm or less.

  Next, the insulating layer 10 will be described in detail.

  The insulating layer 10 includes a resin layer 13 disposed on the core substrate 5 side and an inorganic insulating layer 14 disposed on the side opposite to the core substrate 5. A conductive layer 11 is disposed on a part of one main surface of the inorganic insulating layer 14 opposite to the core substrate 5, and an adjacent insulating layer 10 is disposed on the other main surface of the inorganic insulating layer 14. A part of the resin layer 13 is disposed.

  The resin layer 13 functions as an adhesive member in the insulating layer 10. A part of the resin layer 13 is disposed between the conductive layers 11 disposed on the core substrate 5 side, and functions as an insulating member between the conductive layers 11 separated in the main surface direction. Further, since the resin layer 13 has a Young's modulus smaller than that of the inorganic insulating layer 14 and is easily elastically deformed, the occurrence of cracks in the wiring substrate 3 is suppressed. The thickness of the resin layer 13 is, for example, 3 μm or more and 30 μm or less. The Young's modulus of the resin layer 13 is, for example, not less than 0.2 GPa and not more than 20 GPa. The thermal expansion coefficient in the thickness direction and main surface direction of the resin layer 13 is, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

  As shown in FIG. 1B, the resin layer 13 includes a resin 15 and a plurality of filler particles 16 dispersed in the resin 15.

  The resin 15 functions as an adhesive member in the resin layer 13. As the resin 15, 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 can be used. The Young's modulus of the resin 15 is, for example, not less than 0.1 GPa and not more than 5 GPa. The thermal expansion coefficient in the thickness direction and the main surface direction of the resin 15 is, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

  The filler particles 16 make the resin layer 13 highly rigid and have a low coefficient of thermal expansion. The filler particles 16 are made of an inorganic insulating material such as silicon oxide, aluminum oxide, aluminum nitride, aluminum hydroxide, or calcium carbonate. The average particle diameter of the filler particles 16 is, for example, 0.5 μm or more and 5 μm or less. The thermal expansion coefficient of the filler particles 16 is, for example, 0 ppm / ° C. or more and 15 ppm / ° C. or less. The content ratio of the filler particles 16 in the resin layer 13 is, for example, 3% by volume or more and 60% by volume or less. The average particle size of the filler particles 16 can be measured by calculating the average value of the particle size of each particle in the cross section in the thickness direction of the wiring board 3. In addition, the content ratio of the filler particles 16 in the resin layer 13 is measured by regarding the ratio of the area occupied by the filler particles 16 in the resin layer 13 as the content ratio (volume%) in the cross section in the thickness direction of the wiring board 3. be able to. Hereinafter, the average particle diameter and the content ratio of each member are measured in the same manner as the filler particles 16.

  The inorganic insulating layer 14 functions as a support member for the conductive layer 11. In addition, the inorganic insulating layer 14 reduces the difference in thermal expansion coefficient between the electronic component 2 and the wiring board 3 by making the insulating layer 13 highly rigid and has a low thermal expansion coefficient. When heat is applied to the mounting structure 1, warpage of the wiring board 3 due to a difference in thermal expansion coefficient between the electronic component 2 and the wiring board 3 is reduced. The thickness of the inorganic insulating layer 14 is, for example, 3 μm or more and 30 μm or less. The Young's modulus of the inorganic insulating layer 14 is, for example, 10 GPa or more and 50 GPa or less. Further, the thermal expansion coefficient in the thickness direction and the main surface direction of the inorganic insulating layer 14 is, for example, 0 ppm / ° C. or more and 10 ppm / ° C. or less.

  As shown in FIG. 1B and FIG. 2A, the inorganic insulating layer 14 includes a plurality of inorganic insulating particles 17 that are partially connected to each other, and a plurality of inorganic insulating layers on one main surface of the inorganic insulating layer 14. A first resin portion 18 interposed between the particles 17 and the conductive layer 11 and a second resin portion 19 disposed between the plurality of inorganic insulating particles 17 are included. In this inorganic insulating layer 14, since the plurality of inorganic insulating particles 17 are connected to each other and restrained, the inorganic insulating layer 14 does not flow like the filler particles 16 dispersed in the resin layer 13. And it can be set as a low coefficient of thermal expansion.

  The plurality of inorganic insulating particles 17 constitute an inorganic insulating structure 20 that is a porous body by being connected to each other. The connection portions 21 between the plurality of inorganic insulating particles 17 are constricted and constitute a neck structure.

  The plurality of inorganic insulating particles 17 have a plurality of first inorganic insulating particles 22 that are partially connected to each other and an average particle size larger than that of the first inorganic insulating particles 22, and some of the inorganic insulating particles 17 are connected to the first inorganic insulating particles 22. And a plurality of second inorganic insulating particles 23 that are separated from each other with the first inorganic insulating particles 22 interposed therebetween. The content ratio of the first inorganic insulating particles 22 in the plurality of inorganic insulating particles 17 is, for example, 20 volume% or more and 90 volume% or less, and the content ratio of the second inorganic insulating particles 23 in the plurality of inorganic insulating particles 17 is, for example, 10 The volume is 80% by volume or more.

The first inorganic insulating particle 22 functions as a connecting member in the inorganic insulating particle 17 by connecting a part of the first inorganic insulating particle 22 to each other and connecting the second inorganic insulating particles 23 to each other. The inorganic insulating layer 14 has a high rigidity and a low thermal expansion coefficient. To do. The first inorganic insulating particles 22 are made of, for example, an inorganic insulating material such as silicon oxide, zirconium oxide, aluminum oxide, boron oxide, magnesium oxide, or calcium oxide. Among these, from the viewpoint of low thermal expansion coefficient and low dielectric loss tangent, silicon oxide It is desirable to use In this case, the 1st inorganic insulating particle 22 should just contain 90 mass% or more of silicon oxides. In addition, silicon oxide is desirably in an amorphous state in order to reduce anisotropy of the thermal expansion coefficient due to the crystal structure.

  The first inorganic insulating particles 22 are, for example, spherical. Moreover, the average particle diameter of the 1st inorganic insulating particle 22 is 3 nm or more and 110 nm or less, for example. Thus, since the particle diameter of the 1st inorganic insulating particle 22 is very small, while being able to make the inorganic insulating layer 14 dense, it can be set as a high rigidity and a low thermal expansion coefficient, and the inorganic insulating layer 14 is used as described later. When producing, the first inorganic insulating particles 22 can be easily connected to each other.

  Since the second inorganic insulating particle 23 has a large particle size, the second inorganic insulating particle 23 increases energy for bypassing the crack generated in the inorganic insulating layer 14, and therefore suppresses the extension of the crack. The second inorganic insulating particles 23 can be made of the same material as that of the first inorganic insulating particles 22. In particular, the same material as that of the first inorganic insulating particles 22 is used in order to bring the material properties close to the first inorganic insulating particles 22. It is desirable. The second inorganic insulating particles 23 are, for example, spherical. The average particle size of the second inorganic insulating particles 23 is, for example, not less than 0.5 μm and not more than 5 μm. Thus, since the particle diameter of the 2nd inorganic insulating particle 23 is large, the expansion | extension of the crack which arose in the inorganic insulating layer 14 can be suppressed favorably.

  The first resin portion 18 is disposed in a first gap 24 interposed between the inorganic insulating structure 20 and the conductive layer 11. The first resin portion 18 of the present embodiment is formed by part of the resin layer 13, particularly part of the resin 15 entering the first gap 24. Further, the first resin portion 18 is filled in the first gap 24. Further, the first resin portion 18 is further interposed between the first inorganic insulating particles 22 and the resin layer 13.

  The 2nd resin part 19 is distribute | arranged to the 2nd clearance gap 25 located between the inorganic insulating particles 17 inside the inorganic insulating structure 20 which is a porous body. The second resin portion 19 of the present embodiment is a part in which a part of the resin layer 13, particularly a part of the resin 15 enters the second gap 25. Further, the second resin part 19 of the present embodiment is filled in the second gap 25.

  The first gap 24 and the second gap 25 are connected to each other and are open pores. The second gap 25 has an opening on the other main surface of the inorganic insulating layer 14. The first gap 24 is surrounded by the conductive layer 11 and the inorganic insulating structure 20 in the cross section in the thickness direction of the inorganic insulating layer 14. The second gap 25 is surrounded by the inorganic insulating particles 17 in the cross section in the thickness direction of the inorganic insulating layer 14.

  By the way, when stress is applied to the wiring substrate 3, stress may be applied between the inorganic insulating layer 14 and the conductive layer 11.

  On the other hand, in the present embodiment, the wiring board 3 mainly includes a plurality of convex portions 26 and a plurality of concave portions 27 located between the convex portions 26 as shown in FIGS. 1B and 2A. An inorganic insulating layer 14 on the surface, and a conductive layer 11 partially disposed on one main surface of the inorganic insulating layer 14 and having a recess 28 corresponding to the protrusion 26 and a protrusion 29 corresponding to the recess 27. It has. As a result, since the convex portion 26 is disposed in the recessed portion 28 and the protruding portion 29 is disposed in the concave portion 27, the adhesive strength between the inorganic insulating layer 14 and the conductive layer 11 can be increased by the anchor effect. .

  Further, the inorganic insulating layer 14 includes a plurality of first inorganic insulating particles 22 that are partially connected to each other, and a plurality of first inorganic insulating particles 22 and the conductive layer 11 on one main surface of the inorganic insulating layer 14. And an intervening first resin portion 18. As a result, since heat is applied to the wiring board 3 when the electronic component 2 is mounted or operated, the first resin portion 18 is heated between the plurality of first inorganic insulating particles 22 and the conductive layer 11 that are partially connected to each other. The protrusion 29 of the conductive layer 11 is fixed by expanding. Therefore, the adhesive strength between the inorganic insulating layer 14 and the conductive layer 11 can be increased, and peeling between the inorganic insulating layer 14 and the conductive layer 11 can be reduced. Therefore, for example, the breakage of the connecting portion between the conductive layer 11 and the via conductor 12 can be reduced and the disconnection of the wiring can be reduced, so that the wiring substrate 3 excellent in electrical reliability can be obtained.

  In addition, since the first resin portion 18 is elastically deformed, the stress applied between the inorganic insulating layer 14 and the conductive layer 11 can be relaxed, so that the occurrence of cracks in the inorganic insulating layer 14 can be reduced. . As a result, the disconnection of the wiring due to the crack can be reduced.

  In the present embodiment, the first resin portion 18 is partially interposed between the plurality of first inorganic insulating particles 22 and the conductive layer 11. As a result, when the first resin portion 18 is thermally expanded, the first resin portion 18 is easily fixed by the plurality of first inorganic insulating particles 22, so that the protruding portion 29 is fixed favorably by the first resin portion 18. Can do. In this case, for example, a part of the conductive layer 11 is in contact with the first resin portion 18, and the other part is in contact with the plurality of first inorganic insulating particles 22.

  In the present embodiment, the first resin portion 18 is disposed on the convex portion 26. As a result, since the first resin portion 18 disposed on the convex portion 26 fixes the protruding portion 29 from the side, the protruding portion 29 can be favorably fixed by the first resin portion 18.

  Further, the first resin portion 18 is in contact with the protruding portion 29. As a result, since the first resin portion 18 that is in contact with the protruding portion 29 at the convex portion 26 fixes the side surface of the protruding portion 29, the protruding portion 29 can be favorably fixed by the first resin portion 18.

  In the present embodiment, the first resin portion 18 is disposed on each of the pair of convex portions 26 adjacent to each other across the concave portion 27 in the cross section along the thickness direction (Z direction) of the inorganic insulating layer 14. As a result, the first resin portion 18 disposed on each of the pair of convex portions 26 fixes the protruding portion 29 with the protruding portion 29 interposed therebetween, so that the protruding portion 29 can be fixed favorably by the first resin portion 18.

  Further, the first resin portion 18 disposed in each of the pair of convex portions 26 adjacent to each other with the concave portion 27 interposed therebetween is connected via the bottom portion of the concave portion 27. As a result, the first resin portion 18 connected through the bottom of the concave portion 27 fixes the protruding portion 29 while surrounding the protruding portion 29, so that the protruding portion 29 can be fixed favorably by the first resin portion 18.

  Further, the first resin portion 18 is in contact with the protruding portion 29 sandwiched between a pair of adjacent protruding portions 26. As a result, the first resin portion 18 that is in contact with the side surface of the projecting portion 29 by the one set of convex portions 26 fixes the side surface of the projecting portion 29 while sandwiching the projecting portion 29. 29 can be fixed satisfactorily.

  In the present embodiment, the first resin portion 18 is disposed on the bottom of the recess 27. As a result, since the 1st resin part 18 distribute | arranged to the bottom part of the recessed part 27 fixes the top part of the protrusion part 29, the protrusion part 29 can be fixed favorably.

Further, the first resin portion 18 is in contact with the top of the protruding portion 29. As a result, the first resin portion 18 that is in contact with the top of the protrusion 29 at the bottom of the recess 27 fixes the top of the protrusion 29, so that the protrusion 29 can be fixed well.

  In the present embodiment, the inorganic insulating layer 14 has a second resin portion 19 disposed between the first inorganic insulating particles 22. As a result, when the second resin portion 19 is elastically deformed, the stress applied to the inorganic insulating layer 14 can be relaxed, and the occurrence of cracks in the inorganic insulating layer 14 can be reduced. Therefore, the disconnection of the wiring resulting from this crack can be reduced.

  Further, the second resin portion 19 is connected to the first resin portion 18. As a result, since the first resin portion 18 connected via the second resin portion 19 fixes the protruding portion 29, the protruding portion 29 can be favorably fixed by the first resin portion 18.

  In the present embodiment, the width of the first resin portion 18 is larger than the average particle diameter of the first inorganic insulating particles 22. As a result, the thermal expansion of the first resin portion 18 can be increased, and the protruding portion 29 can be satisfactorily fixed by the first resin portion 18.

  In addition, the width of the second resin portion 19 is smaller than the average particle diameter of the first inorganic insulating particles 22. As a result, the content of the inorganic insulating particles 17 in the inorganic insulating layer 14 can be increased to make the inorganic insulating layer 14 more rigid and have a low thermal expansion coefficient.

  In the present embodiment, the recess 27 is surrounded by the first resin portion 18 in a cross section along the main surface direction (XY plane direction) of the inorganic insulating layer 14 as shown in FIG. As a result, since the first resin portion 18 surrounding the protrusion 29 corresponding to the recess 27 fixes the protrusion 29, the protrusion 29 can be favorably fixed by the first resin portion 18.

  In the present embodiment, the first resin portion 18 and the plurality of first inorganic insulating particles 22 are arranged on the convex portion 26. As a result, in the convex portion 26, the first resin portion 18 is easily fixed by the plurality of first inorganic insulating particles 22 when the first resin portion 18 is thermally expanded. It can be fixed well. Further, the first resin portion 18 and the second inorganic insulating particles 23 are arranged on the convex portion 26. The content ratio of the second inorganic insulating particles 23 in the vicinity region 30 of one main surface of the inorganic insulating layer 14 is higher than the content ratio of the second inorganic insulating particles 23 in the vicinity region 31 of the other main surface of the inorganic insulating layer 14. Many. In addition, the vicinity region 30 of one main surface of the inorganic insulating layer 14 refers to a layered region having a distance of 2 μm or less from one main surface of the inorganic insulating layer 14 (the bottom portion of the recess 27). The vicinity region 31 of the other main surface of the inorganic insulating layer 14 refers to a layered region having a distance of 2 μm or less from the other main surface of the inorganic insulating layer 14.

  In the present embodiment, the height (Z direction) of the convex portion 26 is, for example, 3 μm or more and 6 μm or less, and the width (XY plane direction) of the convex portion 26 is, for example, 2 μm or more and 5 μm or less. The depth (Z direction) of the recess 27 is, for example, 3 μm or more and 6 μm or less, and the width (XY plane direction) of the recess 27 is, for example, 2 μm or more and 5 μm or less. The height of the convex portion 26 can be measured by measuring the height of each of the plurality of convex portions 26 in the cross section in the thickness direction of the wiring board 3 and calculating the average value of these heights. . The width of the convex portion 26, the height of the concave portion 27, and the width of the concave portion 27 can be measured in the same manner as the height of the convex portion 26.

Moreover, the width | variety of the 1st resin part 18 is 0.5 micrometer or more and 3 micrometers or less, for example. As a result, the contraction amount of the first resin portion 18 can be increased by increasing the width of the first resin portion 18. Moreover, the width | variety of the 2nd resin part 19 is 1 nm or more and 70 nm or less, for example. As a result, the content of the inorganic insulating particles 17 in the inorganic insulating layer 14 can be increased by reducing the width of the second resin portion 19. The width of the first resin portion 18 is obtained by measuring the maximum value of the width of each of the plurality of first resin portions 18 in the cross section in the thickness direction of the wiring board 3 and calculating the average value of these maximum values. Can be measured. Second resin part 19
The width of can be measured in the same manner as the width of the first resin portion 18.

  Next, a method for manufacturing the mounting structure 1 described above will be described with reference to FIGS.

  (1) As shown in FIG. 3A, the core substrate 5 is manufactured. Specifically, for example, the following is performed.

  A laminated plate made of a base 7 formed by curing the prepreg and a metal foil such as copper disposed above and below the base 7 is prepared. Next, through holes are formed in the laminate using laser processing, drilling, or the like. Next, the through-hole conductor 8 is formed by depositing a conductive material in the through-hole using, for example, an electroless plating method, an electrolytic plating method, a vapor deposition method, a CVD method, or a sputtering method. Next, the insulator 9 is formed by filling the inside of the through-hole conductor 8 with an uncured resin and curing it. Next, a conductive material is deposited on the insulator 9 using, for example, an electroless plating method, an electrolytic plating method, a vapor deposition method, a CVD method, a sputtering method, or the like, and then a photolithography method, an etching method, or the like. Then, the metal foil and conductive material on the substrate 7 are patterned to form the conductive layer 11. As a result, the core substrate 5 can be manufactured.

  (2) As shown in FIGS. 3 (b) to 5 (c), for example, a support 32 made of a metal foil such as a copper foil or a resin film such as a PET film, and an inorganic material disposed on the support 32. A laminated sheet 34 including the insulating layer 14 and the uncured resin layer precursor 33 disposed on the inorganic insulating layer 14 is produced. Specifically, for example, the following is performed.

  First, as shown in FIGS. 3B and 3C, an inorganic insulating sol 36 having inorganic insulating particles 17 and a solvent 35 in which the inorganic insulating particles 17 are dispersed is prepared, and the inorganic insulating sol 36 is supported on the support. 32 is applied to one main surface. Next, the solvent 35 is evaporated from the inorganic insulating sol 36 to leave the inorganic insulating particles 17 on the support 32. The remaining inorganic insulating particles 17 are in contact with each other at close locations. Next, as shown in FIGS. 4A to 4C, the inorganic insulating structure 17 is heated by heating the inorganic insulating particles 17 and connecting the adjacent inorganic insulating particles 17 to each other at adjacent positions. An inorganic insulating layer 14 having the following is formed. At this time, a first gap 24 interposed between the inorganic insulating particles 17 and the support 32 and a second gap 25 between the inorganic insulating particles 17 are formed. Next, as shown in FIGS. 5A to 5C, a resin layer precursor 33 is laminated on the inorganic insulating layer 14, and the laminated inorganic insulating layer 14 and resin layer precursor 33 are arranged in the thickness direction. A part of the resin layer precursor 33 is filled in the first gap 24 and the second gap 25 by heating and pressing. As a result, the laminated sheet 34 can be produced.

  Here, in the present embodiment, one main surface of the support 32 to which the inorganic insulating sol 36 is applied has a plurality of projecting portions 29 and a recessed portion 28 located between the projecting portions 29. When the inorganic insulating sol 36 is applied to one main surface of the support 32, the inorganic insulating particles 17 are arranged in the depressions 28. Then, after the solvent 35 is evaporated, the inorganic insulating particles 17 are connected to each other to form the inorganic insulating layer 14, thereby forming the concave portion 27 corresponding to the protruding portion 29 and corresponding to the concave portion 28. A convex portion 26 having a shape is formed. As a result, the convex part 26 including the inorganic insulating particles 17 arranged in the hollow part 28 can be formed.

  When the inorganic insulating sol 36 is applied, if the content ratio of the first inorganic insulating particles 22 in the inorganic insulating particles 17 is reduced, a region where the first inorganic insulating particles 22 are not present when the solvent 35 is evaporated is formed. This facilitates the formation of the first gap 24 when the inorganic insulating layer 14 is formed.

Further, if the width of the hollow portion 28 of the support 32 is larger than the average particle diameter of the second inorganic insulating particles 23, the second inorganic insulating particles 23 are disposed in the hollow portion 28 when the inorganic insulating sol 36 is applied. It becomes easy and the content rate of the 1st inorganic insulating particle 22 in the hollow part 28 tends to fall. As a result, the first gap 24 is easily formed in the convex portion 26. In this case, the second inorganic insulating particles 23 are disposed on the convex portions 26. For example, when an electrolytic copper foil is used as the support 32, the shape of the recess 28 can be appropriately adjusted by appropriately adjusting the electrolytic plating conditions.

  When the inorganic insulating sol 36 is applied, if the second inorganic insulating particles 23 are allowed to settle on one main surface of the support 32 by gravity or centrifugal force, the second region in the vicinity of the one main surface of the support 32 is used. Since the content ratio of the first inorganic insulating particles 22 can be reduced by increasing the content ratio of the inorganic insulating particles 23, the first gap 24 is easily formed when the inorganic insulating layer 14 is formed. In this case, the content ratio of the second inorganic insulating particles 23 in the vicinity region 30 of one main surface of the inorganic insulating layer 14 is such that the content of the second inorganic insulating particles 23 in the vicinity region 31 of the other main surface of the inorganic insulating layer 14 is. More than a percentage.

  The content ratio of the inorganic insulating particles 17 in the inorganic insulating sol 36 is, for example, 10% to 50% by volume, and the content ratio of the solvent 35 in the inorganic insulating sol 36 is, for example, 50% to 90% by volume. The solvent 35 is, 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 2 selected from these An organic solvent containing a mixture of seeds or more can be used.

  The inorganic insulating sol 36 is dried by, for example, heating and air drying. The drying temperature is, for example, 20 ° C. or more and less than the boiling point of the solvent 35, and the drying time is, for example, 20 seconds or more and 30 minutes or less.

  The heating temperature for connecting the inorganic insulating particles 17 is not less than the boiling point of the solvent 35 and less than the crystallization start temperature of the inorganic insulating particles 17, and is not less than 100 ° C. and not more than 250 ° C. The heating time is, for example, 0.5 hours or more and 24 hours or less. As described above, the first inorganic insulating particles 22 have an average particle size as small as 3 nm to 110 nm. Therefore, even at such a low temperature, the first inorganic insulating particles 22 and the first inorganic insulating particles 22 The second inorganic insulating particles 23 can be firmly connected. This is because, since the first inorganic insulating particles 22 are minute, the atoms of the first inorganic insulating particles 22, particularly the atoms on the surface, actively move. It is presumed that the first inorganic insulating particles 22 and the second inorganic insulating particles 23 are firmly connected.

  Further, by heating at such a low temperature as described above, the first inorganic insulating particles 22 and the first inorganic insulating particles 22 and the second inorganic insulating particles 22 and the second inorganic insulating particles 22 are maintained while maintaining the particle shapes of the first inorganic insulating particles 22 and the second inorganic insulating particles 23. The inorganic insulating particles 23 can be connected only in the proximity region. As a result, a neck structure can be formed in the connecting portion 20 and the first gap 24 and the second gap 25 of the open pores can be easily formed. The temperature at which the first inorganic insulating particles 22 can be firmly connected is, for example, about 250 ° C. when the average particle size of the first inorganic insulating particles 22 is set to 110 nm or less. When the average particle size of the particles 22 is set to 15 nm or less, the temperature is about 150 ° C.

The pressure at the time of heating and pressurizing the laminated inorganic insulating layer 14 and the resin layer precursor 33 is, for example, 0.5 MPa or more and 2 MPa or less, the pressurizing time is, for example, 60 seconds or more and 10 minutes or less, and the heating temperature is For example, they are 80 degreeC or more and 140 degrees C or less. A part of the resin layer precursor 33 can be satisfactorily filled in the first gap 24 and the second gap 25 by appropriately adjusting the heating and pressing conditions. Since the heating temperature is lower than the curing start temperature of the resin layer precursor 33, the resin layer precursor 33 can be maintained in an uncured state.

  (3) As shown in FIGS. 6A to 7B, the laminated sheet 34 is laminated on the core substrate 5 to form the insulating layer 10, and the conductive layer 11 and the via conductor 12 are formed on the insulating layer 10. Form. Specifically, for example, the following is performed.

  First, as shown in FIG. 6A, a laminated sheet 34 is laminated on the core substrate 5 while the resin layer precursor 33 is in contact with the core substrate 5, and the laminated core substrate 5 and laminated sheet 34 are arranged in the thickness direction. After the laminated sheet 34 is adhered to the core substrate 5 by heating and pressurizing, the resin layer precursor 33 of the laminated sheet 34 is heated at a temperature not lower than the curing start temperature and lower than the thermal decomposition temperature. The body 33 is cured to form the resin layer 13. As a result, the insulating layer 10 having the resin layer 13 and the inorganic insulating layer 14 included in the laminated sheet 34 can be formed on the core substrate 5.

  Next, as shown in FIGS. 6B and 6C, the support 32 is chemically peeled from the inorganic insulating layer 14 using a ferric chloride solution or a copper chloride solution, and then laser Using processing or the like, a via hole that penetrates the insulating layer 10 in the thickness direction and exposes the conductive layer 11 is formed. Next, smear (resin residue) generated in the via hole by laser processing is removed (desmear treatment). Next, as shown in FIGS. 7A and 7B, the insulating layer 10 is formed on the insulating layer 10 by a semi-additive method, a subtractive method, a full additive method, or the like using an electroless plating method or an electrolytic plating method. A conductive layer 11 having a desired pattern is formed, and a via conductor 12 is formed in the via hole. At this time, the conductive layer 11 is disposed on a part of one main surface of the inorganic insulating layer 14 in the insulating layer 10.

  Part of the resin layer precursor 33 that has entered the first gap 24 and the second gap 25 in the step (2) becomes the first resin portion 18 and the second resin portion 19 in this step. At this time, since the first resin portion 18 and the second resin portion 19 are cured and contracted, the protruding portion 28 is fixed by the first resin portion 18. In addition, each condition at the time of heat-pressing the laminated | stacked core board | substrate 5 and the lamination sheet 34 is the same as that of the heat-pressing of a process (2).

  Here, in this embodiment, the protrusions 26 and the recesses 27 formed in the step (2) are exposed by peeling the support 32 from the inorganic insulating layer 14. Then, when the conductive layer 11 is formed on one main surface where the concave portion 27 of the inorganic insulating layer 14 is exposed, the plating solution enters the concave portion 27, so that the concave portion 28 and the protruding portion 29 of the conductive layer 11 can be formed. it can. At this time, since the first resin portion 18 and the second resin portion 19 exposed to the plating solution are dried and contracted, the protruding portion 29 of the conductive layer 11 is fixed by the first resin portion 18. Therefore, in this step, peeling of the conductive layer 11 from the inorganic insulating layer 14 can be reduced, contact between the conductive layers 11 can be reduced, and a short circuit can be reduced.

  (4) As shown in FIGS. 8A and 8B, a laminated sheet 34 is laminated on the insulating layer 10 to further form the insulating layer 10, and the conductive layer 11 and via conductors are formed on the insulating layer 10. By forming 12, the build-up layer 6 is formed on the core substrate 5, and the wiring substrate 3 is produced. Specifically, for example, the following is performed. Here, for convenience, the insulating layer 10 formed in this step is referred to as a first insulating layer 10a, and the insulating layer 10 formed in step (3) is referred to as a second insulating layer 10b.

First, as shown in FIG. 8A, a laminated sheet 34 is laminated on the second insulating layer 10b while the resin layer precursor 33 is in contact with the second insulating layer 10b, and the laminated second insulating layer 10b and After the laminated sheet 34 is heated and pressed in the thickness direction to adhere the laminated sheet 34 to the second insulating layer 10b, the resin layer precursor 33 of the laminated sheet 34 is heated at a temperature not lower than the curing start temperature and lower than the thermal decomposition temperature. By heating, the resin layer precursor 33 is cured to form the resin layer 13. As a result, the first insulating layer 10a having the resin layer 13 and the inorganic insulating layer 14 included in the laminated sheet 34 can be formed on the second insulating layer 10b. Next, as shown in FIG. 8B, the conductive layer 11 and the via conductor 12 are formed in the first insulating layer 10a by the same method as in the step (3). In addition, the build-up layer 6 can be multi-layered by repeating this process.

  Since the resin layer precursor 33 flows when the laminated sheet 34 is adhered to the second insulating layer 10b, the resin layer precursor 33 is disposed on the other part of one main surface of the inorganic insulating layer 14 and is also a conductive layer. 11 side surfaces and one main surface are covered. Therefore, the resin layer 13 of the first insulating layer 10 a covers the side surface and one main surface of the conductive layer 11 disposed on one main surface of the inorganic insulating layer 14. In addition, each condition at the time of heat-pressing the laminated | stacked 2nd insulating layer 10b and the lamination sheet 34 is the same as that of the heat-pressing of a process (2).

  In addition, after forming the insulating layer 10 of all layers, the insulating layer 10 may be further heated at a temperature not lower than the curing start temperature and lower than the thermal decomposition temperature. As a result, when the curing of the first resin portion 18 is incomplete, the degree of curing of the first resin portion 18 can be increased. At this time, since the first resin portion 18 is cured and contracted, the protruding portion 28 is fixed by the first resin portion 18.

  (5) The electronic component 2 is flip-chip mounted on the wiring board 3 via the bumps 4 to produce the mounting structure 1 shown in FIG.

  The present invention is not limited to the above-described embodiments, and various modifications, improvements, combinations, and the like are possible without departing from the spirit of the present invention.

  For example, in the above-described embodiments of the present invention, the configuration using a semiconductor element such as an IC or LSI as the electronic component 2 has been described as an example. However, the electronic component 2 includes a solid-state imaging device such as a CMOS image sensor, an LED, and the like. Alternatively, an acoustic wave device such as a light emitting element, a surface acoustic wave (SAW) device, or a piezoelectric thin film resonator (FBAR) may be used.

  In the above-described embodiment of the present invention, the configuration in which the electronic component 2 is flip-chip mounted on the wiring substrate 3 has been described as an example. However, the electronic component 2 may be mounted on the wiring substrate 3 by wire bonding. The component 2 may be built in the wiring board 3.

  In the above-described embodiment of the present invention, the configuration using the build-up multilayer substrate including the core substrate 5 and the build-up layer 6 as the wiring substrate 3 has been described as an example. For example, a coreless substrate may be used as the wiring substrate 3.

  In the above-described embodiment of the present invention, the configuration in which the inorganic insulating layer 14 is applied to the buildup layer 6 has been described as an example. However, the inorganic insulating layer 14 may be applied to the substrate 7.

  Further, in the above-described embodiment of the present invention, the configuration in which one buildup layer 6 includes two insulating layers 10 has been described as an example. However, one buildup layer 6 includes three or more insulating layers 10. It does not matter.

  In the above-described embodiment of the present invention, the configuration in which the inorganic insulating particles 17 include the second inorganic insulating particles 23 has been described as an example. However, the inorganic insulating particles 17 may not include the second inorganic insulating particles 23. Absent.

  In the above-described embodiment of the present invention, the configuration in which the evaporation of the solvent 35 and the heating of the inorganic insulating particles 17 are separately performed in the step (2) has been described as an example, but these may be performed simultaneously.

  Moreover, in embodiment of this invention mentioned above, although demonstrated the structure which formed the conductive layer 11 after peeling the support body 32 from the inorganic insulating layer 14 at the process (3), from metal foils, such as copper foil, was demonstrated. The support 32 to be formed may be left without being peeled from the inorganic insulating layer 14, and the conductive layer 11 having a desired pattern may be formed by a semi-additive method or a subtractive method. In this case, the protruding portion 28 of the conductive layer 11 is fixed by the curing shrinkage of the first resin portion 18 when the resin layer precursor 33 is cured.

DESCRIPTION OF SYMBOLS 1 Mounting structure 2 Electronic component 3 Wiring board 4 Bump 5 Core board 6 Buildup layer 7 Base body 8 Through-hole conductor 9 Insulator 10 Insulating layer 11 Conductive layer 12 Via conductor 13 Resin layer 14 Inorganic insulating layer 15 Resin 16 Filler particle 17 Inorganic insulating particles 18 First resin part 19 Second resin part 20 Inorganic insulating structure 21 Connection part 22 First inorganic insulating particle 23 Second inorganic insulating particle 24 First gap 25 Second gap 26 Convex part 27 Concave part 28 Depressed part 29 Protrusion 30 Region near one main surface of inorganic insulating layer 31 Region near other main surface of inorganic insulating layer 32 Support 33 Resin layer precursor 34 Laminated sheet 35 Solvent 36 Inorganic insulating sol

Claims (12)

An inorganic insulating layer having a plurality of convex portions and a plurality of concave portions located between the convex portions on one main surface, and partially disposed on the one main surface of the inorganic insulating layer and on the convex portions A conductive layer having a corresponding recess and a protrusion corresponding to the recess,
The inorganic insulating layer includes a plurality of first inorganic insulating particles partially connected to each other, and the first insulating surface of the inorganic insulating layer is interposed between the plurality of first inorganic insulating particles and the conductive layer. A wiring board comprising a first resin portion. The wiring board according to claim 1,
The wiring board, wherein the first resin portion is disposed on the convex portion. The wiring board according to claim 2,
The wiring board, wherein the first resin portion is in contact with the protruding portion. The wiring board according to claim 2,
The wiring board according to claim 1, wherein the first resin portion is arranged on each of the pair of convex portions adjacent to each other across the concave portion in a cross section along the thickness direction of the inorganic insulating layer. The wiring board according to claim 4,
The wiring board, wherein the first resin portion disposed on each of the one set of the convex portions is connected via a bottom portion of the concave portion. The wiring board according to claim 1,
The wiring board according to claim 1, wherein the first resin portion is disposed on a bottom portion of the recess. The wiring board according to claim 6,
The wiring substrate, wherein the first resin portion is in contact with a top portion of the protruding portion. The wiring board according to claim 1,
The wiring board according to claim 1, wherein a width of the first resin portion is larger than an average particle diameter of the first inorganic insulating particles. The wiring board according to claim 1,
The wiring board according to claim 1, wherein the inorganic insulating layer has a second resin portion disposed between the first inorganic insulating particles and connected to the first resin portion. The wiring board according to claim 9,
The width of the second resin portion is smaller than the average particle size of the first inorganic insulating particles. The wiring board according to claim 1,
The wiring substrate, wherein the recess is surrounded by the first resin portion in a cross section along the principal surface direction of the inorganic insulating layer.   12. A mounting structure comprising: the wiring board according to claim 1; and an electronic component mounted on the wiring board and electrically connected to the conductive layer.

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