JP6294024B2 - Wiring board and mounting structure using the same - Google Patents

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.

  For example, Patent Document 1 discloses an insulating layer (resin insulating layer) and a plurality of pads (main surface side connection terminals) electrically connected to an electronic component (chip component) disposed on one main surface of the insulating layer. ) Is described.

  By the way, when a voltage is applied between adjacent pads, the conductive material constituting the pads may be ionized and a part of the pads may extend toward the adjacent pads (ion migration). As a result, adjacent pads are easily short-circuited, and the electrical reliability of the wiring board is likely to be reduced.

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

JP 2010-283043 A

  An object of the present invention is to provide a wiring board excellent in electrical reliability and a mounting structure using the wiring board.

A wiring board according to an embodiment of the present invention includes an insulating layer, a plurality of pads that are arranged on one main surface of the insulating layer and electrically connected to an electronic component, and penetrates the insulating layer in the thickness direction. A plurality of via conductors electrically connected to each of the plurality of pads, wherein one main surface of the insulating layer corresponds to each of the plurality of pads, and a plurality of convex portions with the pads arranged on the top surface And a concave portion disposed between the plurality of convex portions, the insulating layer includes an inorganic insulating layer at least partially disposed on the convex portion, and at least a portion disposed on the convex portion. and a first resin layer, the via conductor is at the convex portion, the inorganic insulating layer and the first resin layer penetrates in the thickness direction, the side surface of the via conductor is covered with the insulating layer, wherein The first resin layer is in contact with the pad at the top surface of the convex portion, and the insulating layer , Further including a second resin layer disposed on the opposite side of the inorganic insulating layer from the first resin layer, at least a part of which is exposed in the recess, and the first resin layer includes the first resin, A plurality of first filler particles dispersed in the first resin, and the second resin layer includes a second resin and a plurality of second filler particles dispersed in the second resin, and the second resin. The content ratio of the second filler particles in the layer is smaller than the content ratio of the first filler particles in the first resin layer .

  A mounting structure according to an embodiment of the present invention includes the above-described wiring board, an electronic component that is mounted on one main surface of the insulating layer of the wiring board and is electrically connected to the pad, the electronic component, and the insulation. A resin member disposed between the main surface of the layer and at least a part of the resin member disposed in the recess.

  According to the wiring board of one embodiment of the present invention, one main surface of the insulating layer corresponds to each of the plurality of pads, and the plurality of protrusions with the pads arranged on the top surface are arranged between the plurality of protrusions. Therefore, short circuit between adjacent pads can be reduced. 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.

It is sectional drawing which cut | disconnected the mounting structure in one Embodiment of this invention in the thickness direction. FIG. 2 is a plan view of one main surface in which a through hole of the wiring board of FIG. 1 is opened. (A) is an enlarged view of R1 part of FIG. 1, (b) is an enlarged view of R2 part of FIG. 3 (a). (A) thru | or (c) is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG. 1, (d) is the elements on larger scale of the slurry of FIG.4 (c). (A) is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG. 1, (b) is the elements on larger scale of the powder layer of FIG. 5 (a), (c) is FIG. It is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG. 5, (d) is the elements on larger scale of the inorganic insulating layer of FIG.5 (c). (A) is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG. 1, (b) is the elements on larger scale of the inorganic insulating layer of Fig.6 (a), (c) is a figure. It is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG. (A) is the elements on larger scale of the inorganic insulating layer of FIG.6 (c), (b) is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG. (A) And (b) is sectional drawing explaining the manufacturing process of the mounting structure shown in FIG.

  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 FIGS. 1 and 2 is used for electronic devices such as various audiovisual devices, home appliances, communication devices, computer devices, and 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, for example, a semiconductor element such as an IC, LSI, CCD, or CMOS, a SAW device, or a MEMS device. 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 wiring substrate 3 includes a substrate 5 and a frame 6 that is disposed on the substrate 5 and has a through hole P that penetrates in the thickness direction (Z direction). The wiring board 3 is mounted on an external circuit board (not shown) such as a mother board.

  The substrate 5 has a function of supplying power and signals for driving or controlling the electronic component 2 from the external circuit substrate to the electronic component 2. The substrate 5 includes a plurality of insulating layers 7, a plurality of conductive layers 8 disposed on the insulating layer 7, and a plurality of via conductors that penetrate the insulating layer 7 in the thickness direction and are electrically connected to the conductive layer 8. 9 and. The plurality of conductive layers 8 are disposed on both main surfaces of the insulating layer 7 and are separated from each other in the thickness direction or the main surface direction (XY plane direction). The conductive layer 8 is not disposed inside the insulating layer 7. The via conductor 9 electrically connects the two conductive layers 8 separated in the thickness direction via the insulating layer 7. In this embodiment, the substrate 5 is a coreless substrate having no core substrate, the insulating layer 7 is two layers, and the conductive layer 8 is three layers. Note that the insulating layer 7 and the conductive layer 8 may have any number of layers.

The insulating layer 7 functions as an insulating member between the conductive layers 8 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. The insulating layer 7 includes a first resin layer 10, an inorganic insulating layer 11 disposed on the opposite side of the electronic component 2 of the first resin layer 10, and an opposite side of the inorganic insulating layer 11 to the first resin layer 10. And a second resin layer 12 disposed on the surface.

  The first resin layer 10 functions as an adhesive member that bonds the insulating layers 7 together or the insulating layer 7 and the frame body 6. As shown in FIG. 3A, the first resin layer 10 includes a first resin 13 and a plurality of first filler particles 14 dispersed in the first resin 13. The thickness of the 1st resin layer 10 is 3 micrometers or more and 30 micrometers or less, for example. The Young's modulus of the first resin layer 10 is, for example, not less than 0.2 GPa and not more than 20 GPa. The coefficient of thermal expansion in each direction of the first resin layer 10 is, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

  In addition, the Young's modulus of the 1st resin layer 10 is measured by the method according to ISO14577-1: 2002 using the nano indenter XP by MTS. Moreover, the thermal expansion coefficient of the 1st resin layer 10 is measured by the measuring method according to JISK7197-1991 using a commercially available TMA (Thermo-Mechanical Analysis) apparatus. Hereinafter, the Young's modulus and the thermal expansion coefficient of each member are measured in the same manner as the first resin layer 10.

  The first resin 13 is a main part of the first resin layer 10 and functions as an adhesive member. The first resin layer 13 is made of a resin material such as an epoxy resin, a bismaleimide triazine resin, a cyanate resin, or a polyimide resin, and is preferably made of an epoxy resin.

  The first filler particles 14 make the first resin layer 10 have a low coefficient of thermal expansion and high rigidity. The first filler particles 14 are made of, for example, an inorganic insulating material such as silicon oxide, aluminum oxide, aluminum nitride, aluminum hydroxide, or calcium carbonate, and are preferably made of silicon oxide. The average particle diameter of the first filler particles 14 is, for example, not less than 0.5 μm and not more than 5 μm. The content rate of the 1st filler particle 14 in the 1st resin layer 10 is 3 volume% or more and 60 volume% or less, for example.

  The average particle diameter of the first filler particles 14 can be measured by calculating the average value of the particle diameters of the respective particles in the cross section in the thickness direction of the wiring board 3. Further, the content ratio of the first filler particles 14 in the first resin layer 10 is the content ratio (volume) of the area occupied by the first filler particles 14 in the first resin layer 10 in the cross section in the thickness direction of the wiring board 3. %). Hereinafter, the average particle diameter and the content ratio of each particle are measured in the same manner as the first filler particle 14.

  Since the inorganic insulating layer 11 has a Young's modulus larger than that of the first resin layer 10 and the second resin layer 12 and a smaller thermal expansion coefficient, the difference in thermal expansion coefficient between the electronic component 2 and the wiring board 3 is reduced. Is. Thereby, when heat is applied to the mounting structure 1 during mounting or operation of the electronic component 2, it is possible to suppress warping due to the difference in thermal expansion coefficient between the electronic component 2 and the wiring board 3. Accordingly, it is possible to suppress the breakage of the connection portion between the electronic component 2 and the wiring board 3 due to the warp, and to improve the connection reliability between the electronic component 2 and the wiring board 3.

As shown in FIGS. 3A and 3B, the inorganic insulating layer 11 includes a plurality of inorganic insulating particles 15 partially connected to each other and a resin disposed in a part of a gap 16 between the inorganic insulating particles 15. Part 17. The inorganic insulating layer 11 forms a porous body having a three-dimensional network structure by connecting the inorganic insulating particles 15 to each other. A connection portion between the plurality of inorganic insulating particles 15 is constricted and has a neck structure. The thickness of the inorganic insulating layer 11 is, for example, 3 μm or more and 30 μm or less. The Young's modulus of the inorganic insulating layer 11 is, for example, 10 GPa or more and 50 GPa or less. The coefficient of thermal expansion in each direction of the inorganic insulating layer 11 is, for example, 0 ppm / ° C. or more and 10
ppm / ° C. or less.

  Since the plurality of inorganic insulating particles 15 are connected to each other and do not flow because they are mutually constrained, the Young's modulus of the inorganic insulating layer 11 is increased and the thermal expansion coefficient in each direction is reduced. The inorganic insulating particles 15 have a plurality of first inorganic insulating particles 18 partly connected to each other and an average particle size larger than that of the first inorganic insulating particles 18, and part of the inorganic insulating particles 15 are connected to the first inorganic insulating particles 18. And a plurality of second inorganic insulating particles 19 that are separated from each other with the first inorganic insulating particles 18 interposed therebetween.

  The first inorganic insulating particles 18 function as a connection member in the inorganic insulating layer 11. Further, since the first inorganic insulating particles 18 have a small average particle size and are firmly connected as described later, the inorganic insulating layer 11 can have a low thermal expansion coefficient and a high Young's modulus. The first inorganic insulating particles 18 are made of, for example, an inorganic insulating material such as silicon oxide, zirconium oxide, aluminum oxide, boron oxide, magnesium oxide, or calcium oxide. Above all, from the viewpoint of low thermal expansion coefficient and low dielectric loss tangent, silicon oxide It is desirable to consist of. This silicon oxide is desirably in an amorphous state in order to reduce the anisotropy of the thermal expansion coefficient due to the crystal structure. The content rate of the silicon oxide in the 1st inorganic insulating particle 18 is 99.9 mass% or more and 100 mass% or less, for example. The first inorganic insulating particles 18 are spherical, for example. The average particle diameter of the first inorganic insulating particles 18 is, for example, not less than 3 nm and not more than 110 nm.

  Since the second inorganic insulating particles 19 have an average particle size larger than that of the first inorganic insulating particles 18, the second inorganic insulating particles 19 suppress the extension of cracks generated in the inorganic insulating layer 11. The second inorganic insulating particles 19 have the same material and characteristics as the first inorganic insulating particles 18, for example. The second inorganic insulating particles 19 are spherical, for example. The average particle diameter of the second inorganic insulating particles 19 is, for example, not less than 0.5 μm and not more than 5 μm.

  The gap 16 is an open pore and has an opening on one main surface and the other main surface of the inorganic insulating layer 11. Further, since the plurality of inorganic insulating particles 15 partially connected to each other form a porous body, at least a part of the gap 16 is surrounded by the inorganic insulating particles 15 in the cross section in the thickness direction of the inorganic insulating layer 11. It is.

  Since the resin portion 17 is made of a resin material that is more easily elastically deformed than the inorganic insulating material, the resin portion 17 reduces the stress applied to the inorganic insulating layer 11 and suppresses the occurrence of cracks in the inorganic insulating layer 11. The resin portion 17 of this embodiment is a part of the first resin layer 10 that has entered the gap 16. As a result, the adhesive strength between the inorganic insulating layer 11 and the first resin layer 10 can be increased.

  Since the second resin layer 12 has a smaller thickness and Young's modulus than the first resin layer 10, it has a function of relieving thermal stress between the inorganic insulating layer 11 and the conductive layer 8. The thickness of the 2nd resin layer 12 is 0.1 micrometer or more and 5 micrometers or less, for example. The Young's modulus of the second resin layer 12 is, for example, not less than 0.05 GPa and not more than 5 GPa. The coefficient of thermal expansion in each direction of the second resin layer 12 is, for example, not less than 20 ppm / ° C. and not more than 100 ppm / ° C.

  As shown in FIG. 3A, the second resin layer 12 includes a second resin 20 and a plurality of second filler particles 21 dispersed in the second resin 20. The content rate of the 2nd filler particle 21 in the 2nd resin layer 12 is 0.05 volume% or more and 10 volume% or less, for example.

  The second resin 20 has the same material and characteristics as the first resin 13, for example. The second filler particles 21 have the same material and characteristics as the first filler particles 14, for example. The second filler particles 21 are, for example, spherical, and the average particle size of the second filler particles 21 is, for example, not less than 0.05 μm and not more than 0.7 μm.

  The conductive layer 8 functions as a wiring such as a ground wiring, a power supply wiring, or a signal wiring. The conductive layer 8 is made of, for example, a conductive material such as copper, silver, gold, aluminum, nickel, or chromium, and is preferably made of copper. The thickness of the conductive layer 8 is, for example, 3 μm or more and 20 μm or less. The coefficient of thermal expansion in each direction of the conductive layer 8 is, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less. The Young's modulus of the conductive layer 8 is, for example, 70 GPa or more and 150 or less GPa.

  The conductive layer 8 is disposed on the electronic component 2 disposed on one main surface of the insulating layer 7 (hereinafter referred to as the first insulating layer 22) disposed on the outermost layer on the electronic component 2 side among the plurality of insulating layers 7. It has the some pad 23 electrically connected. The pad 23 functions as a terminal to which the bump 4 is connected. The via conductor 12 is electrically connected to each of the plurality of pads 23. The pad 23 has a disk shape, for example. The width (diameter) of the pad 23 is, for example, not less than 20 μm and not more than 200 μm.

  The via conductor 12 functions as a wiring together with the conductive layer 8. The via conductor 12 has, for example, the same material and characteristics as the conductive layer 8. The via conductor 12 of this embodiment is filled in the via hole, and has a tapered shape with a small width from the side opposite to the electronic component 2 toward the electronic component 2 side. The width (diameter) of the end portion of the via conductor 12 on the electronic component 2 side is, for example, not less than 10 μm and not more than 100 μm. The width (diameter) of the end portion of the via conductor 12 opposite to the electronic component 2 is, for example, 12 μm or more and 120 μm or less.

  Since the frame body 6 has higher rigidity than the substrate 5, the frame body 6 functions as a reinforcing member that suppresses the warpage of the substrate 5 by being bonded to one main surface of the substrate 5. Also, a mounting component (not shown) is mounted on one main surface of the frame 6 opposite to the core substrate 24. The mounting component constitutes the mounting structure 1 together with the electronic component 2 and the wiring board 3. The mounting component has the same configuration as that of the electronic component 2, for example.

  The frame 6 includes a core substrate 24 bonded to one main surface of the substrate 5 and a buildup layer 25 disposed on the opposite side of the core substrate 24 from the substrate 5.

  The core substrate 24 increases the rigidity of the substrate 5. The core substrate 24 includes a base body 26, a cylindrical through-hole conductor 27 disposed in a through-hole penetrating the base body 26 in the thickness direction, and a columnar insulator 28 surrounded by the through-hole conductor 27. It is out. The base 26 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 through-hole conductor 27 is electrically connected to the conductive layer 8 of the substrate 5 and has, for example, the same material and characteristics as the conductive layer 8. The insulator 28 includes a resin such as an epoxy resin.

  The buildup layer 25 has the same configuration as that of the substrate 5 and is disposed on the opposite side of the core substrate 24 from the substrate 5. As a result, when heat is applied to the wiring substrate 3, the thermal stress applied between the core substrate 24 and the buildup layer 25 works in the opposite direction to the thermal stress applied between the core substrate 24 and the substrate 5. In addition, warping of the wiring board 3 can be suppressed. The buildup layer 25 includes the insulating layer 7, the conductive layer 8, and the via conductor 9, similarly to the substrate 5. The conductive layer 8 and the via conductor 9 of the buildup layer 25 are electrically connected to the mounting component and the through-hole conductor 27, thereby transmitting a power supply or a signal between the mounting component and the external circuit board or the electronic component 2. Functions as wiring.

As shown in FIGS. 1 and 2, the through hole P is opened on one main surface of the wiring board 3 opposite to the substrate 5. Further, the through hole P exposes one main surface of the first insulating layer 22 and the pad 23. In the through hole P, the electronic component 2 and the resin member 29 are disposed. The through hole P has, for example, a quadrangular prism shape.

  The resin member 29 covers the electronic component 2 and is disposed between the electronic component 2 and one main surface of the first insulating layer 22. The resin member 29 constitutes the mounting structure 1 together with the electronic component 2, the wiring board 3, and the mounting component. The resin member 29 includes, for example, a third resin (not shown) and a plurality of third filler particles (not shown) dispersed in the third resin. The content ratio of the third filler particles in the resin member 29 is larger than the content ratio of the first filler particles in the first resin layer 10. As a result, the coefficient of thermal expansion of the resin member 29 can be reduced, and the difference in coefficient of thermal expansion between the resin member 29 and the electronic component 2 can be reduced. The third resin is made of the same material as the first resin 13, for example. The third filler particles are made of the same material as the first filler particles 14, for example.

  In this embodiment, as shown in FIG. 1 and FIG. 3A, one main surface of the first insulating layer 22 corresponds to each of the plurality of pads 23, and a plurality of protrusions with the pads 23 arranged on the top surface. It has the part 30 and the recessed part 31 distribute | arranged between the some convex parts 30. FIG. As a result, the recess 31 is disposed between the adjacent pads 23. Thereby, when a voltage is applied between the adjacent pads 23, the expansion | extension of a part of pad 23 can be reduced. Therefore, a short circuit between adjacent pads 23 caused by ion migration can be reduced, and as a result, a wiring board excellent in electrical reliability can be obtained. In addition, in the plurality of convex portions 30 corresponding to each of the plurality of pads 23 and having the pads 23 arranged on the top surface, one pad 23 is arranged on the top surface of one convex portion 30.

  In the present embodiment, the resin member 29 is disposed between the electronic component 2 and one main surface of the first insulating layer 22, and at least a part thereof is disposed in the recess 31. As a result, peeling between the resin member 29 and one main surface of the first insulating layer 22 can be reduced by the anchor effect. That is, since the peeling location where a part of the pad 23 invades when a voltage is applied between the adjacent pads 23 can be reduced, the extension of a part of the pad 23 can be reduced.

  In the present embodiment, the first insulating layer 22 includes the inorganic insulating layer 11 at least partly disposed on the convex part 30 and the first resin layer 10 at least partly disposed on the convex part 30. . As a result, the Young's modulus of the convex portion 30 can be increased by the inorganic insulating layer 11, so that the breakage of the convex portion 30 can be reduced. Thereby, destruction of the connection part of the pad 23 and the electronic component 2 which were distribute | arranged to the top surface of the convex part 30 can be reduced, and the connection reliability of the wiring board 3 and the electronic component 2 can be improved. Moreover, generation | occurrence | production of the crack in the resin member 29 which started the destruction of the convex part 30 can be reduced. That is, since the crack location of the resin member 29 into which the conductive material constituting the pad 23 invades when a voltage is applied between the adjacent pads 23, the extension of a part of the pad 23 can be reduced.

  In the present embodiment, the via conductor 9 penetrates the inorganic insulating layer 11 and the first resin layer 10 in the thickness direction at the convex portion 30. In general, the thermal expansion coefficient of a metal material that is a conductive material is larger than the thermal expansion coefficient of the inorganic insulating material and smaller than the thermal expansion coefficient of the resin material. The thermal expansion coefficient is larger than the thermal expansion coefficient of the first resin layer 10. Therefore, since the thermal expansion coefficient in the thickness direction of the via conductor 9 and the thermal expansion in the thickness direction of the convex portion 30 can be made closer, the thermal stress applied to the connection portion between the via conductor 9 and the pad 23 can be reduced. Therefore, the breakage of the connection portion between the via conductor 9 and the pad 23 can be reduced, and the electrical reliability of the wiring board 3 can be increased.

In the present embodiment, the first resin layer 10 is in contact with the pad 23 at the top surface of the convex portion 30. As a result, the first resin layer 10 can increase the adhesive strength between the convex portion 30 and the pad 23 and reduce the peeling between the convex portion 30 and the pad 23. Thereby, destruction of the connection part of the pad 23 and the electronic component 2 which were distribute | arranged to the top surface of the convex part 30 can be reduced. In addition, it is possible to reduce the occurrence of cracks in the resin member 29 starting from the separation between the protrusion 30 and the pad 23.

  In the present embodiment, the first resin layer 10 is exposed on the top surface of the convex portion 30, and fine irregularities are formed on the top surface of the convex portion 30. As a result, the adhesive strength between the top surface of the convex portion 30 and the pad 23 can be increased. The arithmetic average roughness (Ra) of the top surface of the convex portion 30 is, for example, not less than 0.1 μm and not more than 3 μm. The arithmetic average roughness (Ra) of the top surface of the convex portion 30 is measured according to JIS B0601: 2001 in the cross section along the thickness direction of the wiring board 3. Hereinafter, the arithmetic average roughness (Ra) of each member is measured in the same manner as the convex portion 30.

  In the present embodiment, the second resin layer 12 is disposed on the opposite side of the inorganic insulating layer 11 from the first resin layer 10, and at least a part thereof is exposed in the recess 31. As a result, the adhesive strength between the inner surface of the recess 31 and the resin member 29 can be increased by the second resin layer 12, and peeling between the one main surface of the first insulating layer 22 and the resin member 29 can be reduced.

  In the present embodiment, the second resin layer 12 is exposed on the bottom surface of the recess 31, and fine irregularities are formed on the bottom surface of the recess 31. As a result, the adhesive strength between the bottom surface of the recess 31 and the resin member 29 can be increased. The arithmetic average roughness (Ra) of the bottom surface of the recess 31 is, for example, not less than 0.1 μm and not more than 3 μm.

  In the present embodiment, the content ratio of the second filler particles 21 in the second resin layer 12 is smaller than the content ratio of the first filler particles 14 in the first resin layer 10. As a result, the adhesive strength between the inner surface of the recess 31 and the resin member 29 can be increased by reducing the content ratio of the second filler particles 21 in the second resin layer 12. Further, by increasing the content ratio of the first filler particles 14 in the first resin layer 10, the difference in the thermal expansion coefficient between the convex portion 30 and the pad 23 is reduced while increasing the rigidity of the convex portion 30, and the convex portion 30. And the pad 23 can be separated.

  In the present embodiment, the thickness of the second resin layer 12 is smaller than the thickness of the first resin layer 10. As a result, by reducing the thickness of the second resin layer 12 exposed in the concave portion 31, the rigidity at the bottom of the convex portion 30 can be increased. Thereby, the rigidity of the convex part 30 with respect to the stress to a main surface direction can be improved, and the connection reliability of the wiring board 3 and the electronic component 2 can be improved by extension. Further, by increasing the thickness of the first resin layer 10 disposed on the convex portion 30, the thermal expansion coefficient in the thickness direction of the via conductor 9 and the thermal expansion in the thickness direction of the convex portion 30 can be brought close to each other. .

  In the present embodiment, the width of the convex portion 30 decreases from the bottom portion toward the top surface. As a result, by increasing the width of the bottom portion of the convex portion 30, the strength of the bottom portion of the convex portion 30 can be increased and the breakage of the convex portion 30 can be reduced. Further, by reducing the width of the top surface of the convex portion 30, the resin member 29 can be easily filled into the concave portion 31, and the gap between the resin member 29 and the inner surface of the concave portion 31 can be reduced.

  In the present embodiment, the convex portion 30 has a columnar shape, for example, a truncated cone shape. Moreover, the side surface of the convex part 30 is, for example, a curved surface. As a result, the rigidity at the bottom of the convex portion 30 can be increased. Further, the entire top surface of the convex portion 30 is covered with the pad 23. As a result, the width of the top surface of the convex portion 30 can be reduced, and the resin member 29 can be easily filled into the concave portion 31. The width (diameter) of the top surface of the convex portion 30 is, for example, 20 μm or more and 200 μm or less. Moreover, the height of the convex part 30 is 10 micrometers or more and 50 micrometers or less, for example.

In the present embodiment, the first insulating layer 22 has an adhesive portion 32 adhered to the frame body 6, and a concave portion 31 is disposed between the adhesive portion 32 and the convex portion 30 adjacent to the adhesive portion 32. ing. As a result, the concave portion 31 surrounds the convex portion 30 adjacent to the adhesive portion 32. Therefore, when the resin member 29 is cured in the recess 31, the stress in the principal surface direction applied to the projection 30 due to the curing shrinkage of the resin member 29 becomes more uniform in the circumferential direction of the projection 30. 3 and the connection reliability of the electronic component 2 can be improved. The adhesive portion 32 includes the first resin layer 10 and the inorganic insulating layer 11.

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

  (1) As shown in FIG. 4A, the core substrate 24 is manufactured. Specifically, for example, the following is performed.

  A laminated plate made of a base 26 made by curing the prepreg and a metal foil such as a copper foil disposed on both main surfaces of the base 26 is prepared. Next, through holes are formed in the laminate using laser processing, drilling, or the like. Next, a cylindrical through-hole conductor 27 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, or a sputtering method. Next, the insulator 28 is formed by filling the inside of the through-hole conductor 27 with an uncured resin and curing it. Next, a conductive layer including the pad 23 is formed by depositing a conductive material on the insulator 28 using, for example, an electroless plating method or an electrolytic plating method, and then patterning the metal foil and the conductive material on the base 26. 8 is formed. The core substrate 24 can be manufactured as described above.

  (2) As shown in FIGS. 4B to 6B, the support sheet 33, the inorganic insulating layer 11 disposed on the support sheet 33, and the uncured resin disposed on the inorganic insulating layer 11 A laminated sheet 35 having a resin layer precursor 34 including Specifically, for example, the following is performed.

  First, as shown in FIG. 4B, a metal foil with resin 36 having a support sheet 33 and a second resin layer 12 disposed on the support sheet 33 is prepared. Next, as shown in FIGS. 4C and 4D, a slurry 38 having inorganic insulating particles 15 and a solvent 37 in which the inorganic insulating particles 15 are dispersed is prepared. Apply to the main surface. Next, as shown in FIGS. 5 (a) and 5 (b), the solvent 37 is evaporated from the slurry 38 to leave the inorganic insulating particles 15 on the support sheet 33, and the powder composed of the remaining inorganic insulating particles 15. Layer 39 is formed. In the powder layer 39, the first inorganic insulating particles 18 are in contact with each other at close positions. Next, as shown in FIGS. 5C and 5D, the inorganic insulating layer 11 is formed by heating the powder layer 39 and connecting the adjacent first inorganic insulating particles 18 at adjacent locations.

  Next, as shown in FIGS. 6A and 6B, a resin layer precursor 34 including an uncured resin to be the first resin 13 and the first filler particles 14 is laminated on the inorganic insulating layer 11, and the lamination is performed. A portion of the resin layer precursor 34 is filled in the gap 16 by heating and pressurizing the inorganic insulating layer 11 and the resin layer precursor 34 in the thickness direction. The laminated sheet 35 can be produced as described above.

  In the present embodiment, a slurry 38 containing a plurality of first inorganic insulating particles 18 having an average particle diameter of 3 nm or more and 110 nm or less and a solvent 37 in which the first inorganic insulating particles 18 are dispersed is applied onto the support sheet 33. ing. As a result, since the average particle diameter of the first inorganic insulating particles 18 is 3 nm or more and 110 nm or less, a part of the plurality of first inorganic insulating particles 18 can be firmly connected to each other even under a low temperature condition. This is because, since the first inorganic insulating particles 18 are very small, the atoms of the first inorganic insulating particles 18, particularly the atoms on the surface, actively move. It is presumed that the temperature connected to is reduced.

  Therefore, the plurality of first inorganic insulating particles 18 can be firmly connected to each other under a low temperature condition of less than the crystallization start temperature of the first inorganic insulating particles 18 and further 250 ° C. or less. Further, by heating at such a low temperature, the first inorganic insulating particles 18 and the first inorganic insulating particles 18 and the second inorganic insulating particles 18 and the second inorganic insulating particles 18 are maintained while maintaining the particle shapes of the first inorganic insulating particles 18 and the second inorganic insulating particles 19. The inorganic insulating particles 19 can be connected only in the proximity region. As a result, the open pore gap 16 can be easily formed. Further, the first inorganic insulating particles 18 can be firmly connected to each other at a temperature lower than the thermal decomposition temperature of the second resin 20 of the second resin layer 12. Therefore, damage to the second resin layer 12 can be reduced.

  The temperature at which the first inorganic insulating particles 18 can be firmly connected is, for example, about 250 ° C. when the average particle size of the first inorganic insulating particles 18 is set to 110 nm. When the average particle size of 18 is set to 15 nm, it is about 150 ° C.

  In this embodiment, the slurry 38 further including a plurality of second inorganic insulating particles 19 having an average particle diameter of 0.5 μm or more and 5 μm or less is applied on the support sheet 33. As a result, since the gap between the inorganic insulating particles 15 in the slurry 38 can be reduced by the second inorganic insulating particles 19 having an average particle size larger than that of the first inorganic insulating particles 18, the powder layer 39 formed by evaporating the solvent 37 can be used. Shrinkage can be reduced. Therefore, the occurrence of cracks along the thickness direction of the powder layer 39 can be reduced by reducing the shrinkage of the powder layer 39 which is flat and easily contracts in the main surface direction.

  The support sheet 33 is, for example, a resin film such as a PET film or a metal foil such as a copper foil. The solvent 37 is, for example, methanol, isopropanol, methyl ethyl ketone, methyl isobutyl ketone, xylene, or an organic solvent containing a mixture of two or more selected from these. The drying temperature of the slurry 38 is, for example, 20 ° C. or higher and lower than the boiling point of the solvent 37. The heating temperature at the time of heating the powder layer 39 is not less than the boiling point of the solvent 37 and less than the crystallization start temperature of the first inorganic insulating particles 18, and is not less than 100 ° C. and not more than 250 ° C.

  The heating temperature when heating and pressurizing the laminated inorganic insulating layer 11 and resin layer precursor 34 is, for example, 50 ° C. or more and 100 ° C. or less. In addition, since this heating temperature is less than the curing start temperature of the resin layer precursor 34, the resin layer precursor 34 can be maintained in an uncured state.

  (3) As shown in FIGS. 6C to 7B, the laminated sheet 35 is laminated on the core substrate 24 to form the insulating layer 7, and then the conductive layer 8 and the via conductor 12 are formed. Specifically, for example, the following is performed.

  First, the laminated sheet 35 is laminated on each of both main surfaces of the core substrate 24 while the resin layer precursor 34 is disposed on the core substrate 24 side. Next, the laminated sheet 35 is bonded to the core substrate 24 by heating and pressing the laminated core substrate 24 and laminated sheet 35 in the thickness direction. Next, as shown in FIG. 6C and FIG. 7A, the resin layer precursor 34 is heated to cure the uncured resin to form the first resin 13. One resin layer 10 is used. As a result, the insulating layer 7 can be formed. At this time, a part of the resin layer precursor 34 that has entered the gap 16 in the step (2) becomes the resin portion 17.

  Next, after chemically or mechanically peeling the support sheet 33 from the insulating layer 7, a via hole penetrating the insulating layer 7 in the thickness direction is formed using laser processing. At this time, the conductive layer 8 is exposed on the bottom surface of the via hole. Next, as shown in FIG. 7B, the via conductor 9 is formed in the via hole by the semi-additive method or the subtractive method using the electroless plating method and the electrolytic plating method. A conductive layer 8 is formed.

  The same conditions as in the step (2) can be used for heat and pressure when the laminated sheet 35 is bonded to the core substrate 24. In addition, the heating temperature when the uncured resin is cured to form the first resin 13 is, for example, not less than the curing start temperature of the uncured resin and less than the thermal decomposition temperature.

  (4) As shown in FIG. 8A, the build-up layer 25 is formed on the other main surface of the core substrate 24 while the substrate 5 is formed on one main surface of the core substrate 24 by repeating the step (3). Form. In this step, the core substrate 24 and the buildup layer 25 constitute a flat plate having no through hole P. By repeating this step, the substrate 5 and the buildup layer 25 can be made more multilayered.

  (5) As shown in FIG. 8B, the frame body 6 having the through holes P is formed by using the sandblast method, and the wiring board 3 is formed. Specifically, for example, the following is performed.

  First, by penetrating the buildup layer 25 and the core substrate 24 in the thickness direction by injecting abrasive grains toward one main surface of the buildup layer 25 opposite to the core substrate 24 using a sandblast method. A hole P is formed, and one main surface of the first insulating layer 22 and the pad 23 are exposed in the through hole P. Further, by using abrasive blasting to spray the abrasive grains onto one main surface of the first insulating layer 22 and the pad 23 using the sand blasting method, a region not covered with the pad 23 of the first insulating layer 22 is formed using the pad 23 as a mask. To cut. Thereby, the recessed part 31 distribute | arranged between the convex part 30 and the convex part 30 which the pad 23 distribute | arranged to the top surface is formed.

  In the present embodiment, the first insulating layer 22 includes the second resin layer 12 disposed on the opposite side of the inorganic insulating layer 11 from the first resin layer 10. In general, since the resin material is less likely to be cut by sandblasting than the inorganic insulating material, the second resin layer 12 is less likely to be cut than the inorganic insulating layer 11. Therefore, when the first insulating layer 22 is cut by the sandblast method, the second resin layer 12 functions as a cutting stop layer, and the cutting can be easily stopped in the second resin layer 12. Therefore, the height of the convex portion 30 and the depth of the concave portion 31 can be easily adjusted. In this case, the second resin layer 12 is exposed on the bottom surface of the recess 31.

  In the present embodiment, the content ratio of the second filler particles 21 in the second resin layer 12 is smaller than the content ratio of the first filler particles 14 in the first resin layer 10. As a result, by reducing the content ratio of the second filler particles 21 in the second resin layer 12, the second resin layer 12 can be made less likely to be cut and cutting can be stopped more easily in the second resin layer 12. . Moreover, by making the content rate of the 1st filler particle 14 in the 1st resin layer 10 large, the 1st resin layer 10 is made easier to cut, and the convex part 30 containing the 1st resin layer 10 and the inorganic insulating layer 11 is formed. It can be formed easily.

  The abrasive grains sprayed by the sandblast method are made of an inorganic material such as silicon oxide, aluminum oxide, or silicon carbide. Moreover, the average particle diameter of an abrasive grain is 2 micrometers or more and 80 micrometers or less, for example. The abrasive grains are sprayed, for example, by air (drive last). Further, in the sand blasting method, the convex portion 30 and the concave portion 31 can be formed into desired shapes by appropriately adjusting the shape of the abrasive grains, the spray pressure of the abrasive grains, and the spray time of the abrasive grains.

  (6) The mounting structure 1 shown in FIG. 1 is manufactured by mounting the electronic component 2 on the wiring substrate 3 and covering the electronic component 2 with the resin member 29. Specifically, for example, the following is performed.

First, the electronic component 2 is accommodated in the through hole P of the wiring substrate 3, and the electronic component 2 is flip-chip mounted on the substrate 5 via the bumps 4. At this time, the bump 4 and the pad 23 are electrically connected. Next, a liquid uncured resin member is disposed in the through hole P of the wiring board 3. At this time, the electronic component 2 is covered with the uncured resin member, the uncured resin member is disposed between the electronic component 2 and one main surface of the first insulating layer 22, and the uncured resin is further provided in the recess 31. Arrange the members. Next, the resin member 29 is formed by thermosetting the uncured resin member. As a result, the mounting structure 1 can be manufactured.

  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 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. .

  In the above-described embodiment of the present invention, the configuration in which the mounting structure 1 includes the mounting component mounted on the frame 6 has been described as an example. However, the mounting structure 1 does not include the mounting component. It doesn't matter.

  Further, in the above-described embodiment of the present invention, the example in which the wiring substrate 3 including the substrate 5 and the frame body 6 is used has been described. However, another wiring substrate 3 may be used, for example, the wiring substrate 3. May not have the frame 6.

  In the above-described embodiment of the present invention, the configuration in which the substrate 5 is a coreless substrate has been described as an example. However, the substrate 5 may be a buildup substrate having a core substrate and a buildup layer.

  Further, in the above-described embodiment of the present invention, the configuration in which the frame body 6 includes the core substrate 24 and the buildup layer 25 has been described as an example. However, another frame body 6 may be used. May consist of only the core substrate 24, and the frame 6 may consist of a metal plate, a resin plate, or the like.

  In the above-described embodiment of the present invention, the configuration in which the insulating layer 7 includes the first resin layer 10, the inorganic insulating layer 11, and the second resin layer 12 has been described as an example. However, the insulating layer 7 is the first resin layer. 10 and the inorganic insulating layer 11 may be provided, and the second resin layer 12 may not be provided.

  In the above-described embodiment of the present invention, the configuration in which the inorganic insulating particles 15 include the second inorganic insulating particles 19 has been described as an example. However, the inorganic insulating particles 15 may not include the second inorganic insulating particles 19. I do not care.

  In the embodiment of the present invention described above, the configuration in which the via conductor 12 is filled in the via hole has been described as an example. However, the via conductor 12 may have a film shape attached to the inner wall of the via hole. Absent.

  In the embodiment of the present invention described above, the configuration in which the first resin layer 10 is in contact with the pad 23 on the top surface of the convex portion 30 has been described as an example. However, the inorganic insulating layer 11 is on the top surface of the convex portion 30. It may be in contact with the pad 23.

  In the above-described embodiment of the present invention, the configuration in which the evaporation of the solvent 37 and the heating of the powder layer 39 are separately performed in the step (2) has been described as an example, but these may be performed simultaneously.

In the above-described embodiment of the present invention, the structure in which the conductive layer 8 is formed on one main surface of the insulating layer 7 after the support sheet 33 is removed from the insulating layer 7 in the step (3) has been described as an example.
The conductive layer 8 may be formed by patterning the support sheet 33 made of metal foil on the insulating layer 7.

DESCRIPTION OF SYMBOLS 1 Mounting structure 2 Electronic component 3 Wiring board 4 Bump 5 Board | substrate 6 Frame 7 Insulating layer 8 Conductive layer 9 Via conductor 10 1st resin layer 11 Inorganic insulating layer 12 2nd resin layer 13 1st resin 14 1st filler particle 15 Inorganic insulating particles 16 Gap 17 Resin portion 18 First inorganic insulating particles 19 Second inorganic insulating particles 20 Second resin 21 Second filler particles 22 First insulating layer 23 Pad 24 Core substrate 25 Build-up layer 26 Base body 27 Through-hole conductor 28 Insulator 29 Resin member 30 Convex part 31 Concave part 32 Adhesive part 33 Support sheet 34 Resin layer precursor 35 Laminated sheet 36 Metal foil with resin 37 Solvent 38 Slurry 39 Powder layer P Through-hole

Claims (4)

Insulating layer, a plurality of pads arranged on one main surface of the insulating layer and electrically connected to the electronic component, and through the insulating layer in the thickness direction and electrically connected to each of the plurality of pads With a plurality of via conductors,
One main surface of the insulating layer corresponds to each of the plurality of pads, and has a plurality of convex portions with the pads arranged on the top surface, and concave portions arranged between the plurality of convex portions,
The insulating layer includes an inorganic insulating layer at least partially disposed on the convex portion, and a first resin layer at least partially disposed on the convex portion,
The via conductor penetrates the inorganic insulating layer and the first resin layer in the thickness direction at the convex portion, and a side surface of the via conductor is covered with the insulating layer.
And
The first resin layer is in contact with the pad at the top surface of the convex portion,
The insulating layer further includes a second resin layer disposed on the opposite side of the inorganic insulating layer from the first resin layer, at least a part of which is exposed in the recess,
The first resin layer includes a first resin and a plurality of first filler particles dispersed in the first resin,
The second resin layer includes a second resin and a plurality of second filler particles dispersed in the second resin,
The wiring board according to claim 1, wherein a content ratio of the second filler particles in the second resin layer is smaller than a content ratio of the first filler particles in the first resin layer . The wiring board according to claim 1 ,
The wiring board, wherein the thickness of the second resin layer is smaller than the thickness of the first resin layer. The wiring board according to claim 1,
The width of the convex portion is reduced from the bottom toward the top surface. The wiring board according to any one of claims 1 to 3, an electronic component mounted on one main surface of the insulating layer of the wiring board and electrically connected to the pad, the electronic component and the insulating layer A mounting structure comprising: a resin member disposed between the main surface and at least a portion of the resin member disposed in the recess.

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