JP6133689B2 - 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.

  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, since the coefficient of thermal expansion is different between the inorganic insulating layer and the conductive layer, if heat is applied to the wiring board during mounting or operation of the electronic component, stress is applied between the inorganic insulating layer and the conductive layer, and the inorganic insulating layer And the conductive layer may peel off. As a result, the conductive layer is disconnected, and the electrical reliability of the wiring board is likely to decrease.

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

JP 2005-223226 A

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

A wiring board according to an embodiment of the present invention includes an inorganic insulating layer and a conductive layer partially disposed on one main surface of the inorganic insulating layer, and the inorganic insulating layer includes a plurality of interconnected parts. Including the first inorganic insulating particles and a plurality of second inorganic insulating particles having an average particle size larger than that of the first inorganic insulating particles and spaced apart from each other with the first inorganic insulating particles interposed therebetween. The one main surface of the layer is located between a plurality of convex portions including the first inorganic insulating particles and the second inorganic insulating particles, and the adjacent convex portions, and a part of the conductive layer is disposed. A first recess. The inorganic insulating layer further includes a resin portion disposed in a gap between the first inorganic insulating particles, and the convex portion further includes the resin portion. Or the surface of the said 2nd inorganic insulating particle contained in the said convex part is covered with the said 1st inorganic insulating particle. Or the average particle diameter of the said 2nd inorganic insulating particle contained in the said convex part is larger than the average particle diameter of the said 2nd inorganic insulating particle contained in the vicinity area | region of the other main surface of the said 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 adhesive strength between the inorganic insulating layer and the conductive layer can be increased. Therefore, it is possible to obtain a wiring substrate that reduces the disconnection of the conductive layer and thus has excellent electrical reliability.

  According to the mounting structure in one embodiment of the present invention, since the wiring board 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 sectional drawing which expanded and showed R3 part of FIG.1 (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 R4 part of FIG.3 (b) FIG. (A) is sectional drawing which expanded and showed R5 part of FIG.3 (c), (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a). (A) is sectional drawing which expanded and showed R6 part of FIG.4 (b), (b) is sectional drawing which expanded and showed R7 part of Fig.5 (a). (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 R8 part of Fig.6 (a). (A) is sectional drawing which expanded and showed R9 part of FIG.6 (b), (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a). (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 R10 part of Fig.8 (a). (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 R11 part of Fig.9 (a). (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 R12 part of Fig.10 (a). It 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 motherboard 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, not less than 0.5 μm and not more than 5 μm. 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 FIGS. 1B and 2B, the inorganic insulating layer 14 includes a plurality of inorganic insulating particles 17 partially connected to each other and a resin portion disposed in a gap 18 between the inorganic insulating particles 17. 19 is included. In the 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. A low coefficient of thermal expansion can be obtained.

  The plurality of inorganic insulating particles 17 constitutes a porous body or a three-dimensional network structure in which gaps 18 are formed by being connected to each other. Moreover, the connection part 20 between the plurality of inorganic insulating particles 17 is constricted and constitutes a neck structure.

The plurality of inorganic insulating particles 17 have a plurality of first inorganic insulating particles 17a partly connected to each other, and an average particle size larger than that of the first inorganic insulating particles 17a, and partly connected to the first inorganic insulating particles 17a. And a plurality of second inorganic insulating particles 17b that are separated from each other with the first inorganic insulating particles 17a interposed therebetween. The content ratio of the first inorganic insulating particles 17a in the plurality of inorganic insulating particles 17 is, for example, 20% by volume or more and 90% by volume or less, and the content ratio of the second inorganic insulating particles 17b 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 17a functions as a connecting member in the inorganic insulating particle 17 by connecting a part of the first inorganic insulating particle 17a to each other and connecting the second inorganic insulating particle 17b 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 17a 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 use In this case, the 1st inorganic insulating particle 17a 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 17a are, for example, spherical. The average particle diameter of the first inorganic insulating particles 17a is, for example, not less than 3 nm and not more than 110 nm. As described above, since the first inorganic insulating particles 17a have a very small particle size, the inorganic insulating layer 14 can be made dense so as to have high rigidity and a low thermal expansion coefficient. When producing, the first inorganic insulating particles 17a can be easily connected to each other.

  Since the second inorganic insulating particle 17b has a large particle size, the second inorganic insulating particle 17b increases energy for bypassing the crack generated in the inorganic insulating layer 14, and thus suppresses the extension of the crack. The second inorganic insulating particles 17b can be made of the same material as that of the first inorganic insulating particles 17a. Among them, the same material as that of the first inorganic insulating particles 17a is used in order to bring the material properties closer to those of the first inorganic insulating particles 17a. It is desirable. The second inorganic insulating particles 17b are, for example, spherical. The average particle size of the second inorganic insulating particles 17b is, for example, not less than 0.5 μm and not more than 5 μm. Thus, since the particle size of the 2nd inorganic insulating particle 17b is large, the expansion | extension of the crack which arose in the inorganic insulating layer 14 can be suppressed favorably.

  The gap 18 is an open pore and has an opening on the other main surface of the inorganic insulating layer 14. In addition, at least a part of the gap 18 is surrounded by the inorganic insulating particles 17 in the cross section in the thickness direction of the inorganic insulating layer 14.

  The resin portion 19 is elastically deformed in the gap 18 to relieve stress applied to the inorganic insulating layer 14 and suppress the generation of cracks in the inorganic insulating layer 14. The resin portion 19 of the present embodiment is formed by part of the resin layer 13, particularly part of the resin 15 entering the gap 18. In addition, the ratio for which the resin part 19 accounts in the inorganic insulating layer 14 is 10 volume% or more and 50 volume% or less, for example.

  By the way, since the thermal expansion coefficient differs between the inorganic insulating layer 14 and the conductive layer 11, stress is applied between the inorganic insulating layer 14 and the conductive layer 11 when heat is applied to the wiring board 3 during mounting or operation of the electronic component 2. May be added.

  On the other hand, the wiring board 3 of the present embodiment includes an inorganic insulating layer 14 and a conductive layer partially disposed on one main surface of the inorganic insulating layer 14 as shown in FIGS. 11 and the inorganic insulating layer 14 has a plurality of first inorganic insulating particles 17a partially connected to each other, an average particle size larger than the first inorganic insulating particles 17a, and sandwiches the first inorganic insulating particles 17a. A plurality of second inorganic insulating particles 17b separated from each other, and one main surface of the inorganic insulating layer 14 includes a plurality of convex portions 21 including the first inorganic insulating particles 17a and the second inorganic insulating particles 17b; The first recess 22a is located between the adjacent protrusions 21 and part of the conductive layer 11 is disposed.

As a result, since a part of the conductive layer 11 is disposed in the first recess 22a, the adhesion strength between the conductive layer 11 and the inorganic insulating layer 14 can be increased by the anchor effect, and the conductive layer 11 and the inorganic insulating layer can be increased. 14 can be prevented from peeling.

  Furthermore, since the convex part 21 contains the 2nd inorganic insulating particle 17b, generation | occurrence | production of the crack in the convex part 21 can be suppressed by this 2nd inorganic insulating particle 17b. Moreover, since the convex part 21 contains the 1st inorganic insulating particle 17a, the 2nd inorganic insulating particle 17b contained in the convex part 21 by this 1st inorganic insulating particle 17a and the main part 23 (inorganic insulation layer 14) of the inorganic insulating layer 14 are included. The connection strength with the region 14 other than the convex portion 21 of the layer 14 can be increased. Therefore, since the destruction of the convex portion 21 can be suppressed when a stress is applied between the inorganic insulating layer 14 and the conductive layer 11, the anchor effect described above is maintained, and the adhesive strength between the conductive layer 11 and the inorganic insulating layer 14 is maintained. Can be maintained.

  Moreover, since the convex part 21 contains the 2nd inorganic insulating particle 17b with high chemical resistance and plasma resistance compared with the 1st inorganic insulating particle 17a, the damage of the convex part 21 at the time of formation of the conductive layer 11 is carried out. Can be suppressed, and the destruction of the convex portion 21 can be suppressed.

  Moreover, since the convex part 21 contains the 1st inorganic insulating particle 17a, it is easy to produce a fine unevenness | corrugation on the surface of the convex part 21 with the 1st inorganic insulating particle 17a. As a result, the adhesive strength between the convex portion 21 and the conductive layer 11 can be increased by the anchor effect, and as a result, the adhesive strength between the conductive layer 11 and the inorganic insulating layer 14 can be increased.

  In the wiring substrate 3 of the present embodiment, as shown in FIGS. 2A and 2B, the inorganic insulating layer 14 includes the resin portion 19 disposed in the gap 18 between the first inorganic insulating particles 17a. Further, the convex portion 21 further includes a resin portion 19. As a result, the resin portion 19 disposed in the gap 18 between the first inorganic insulating particles 17a in the convex portion 21 is elastically deformed, so that the stress applied to the convex portion 21 can be relaxed and the destruction of the convex portion 21 can be suppressed. .

  Further, as shown in FIGS. 1B and 2A, the surface of the second inorganic insulating particles 17b included in the convex portion 21 is covered with the first inorganic insulating particles 17a. As a result, fine irregularities are likely to occur on the surface of the convex portion 21, so that the adhesive strength between the convex portion 21 and the conductive layer 11 can be increased.

  Further, as shown in FIGS. 1B and 2A, the first inorganic insulating particles 17 a are exposed on the surface of the convex portion 21. As a result, fine irregularities are likely to occur on the surface of the convex portion 21, so that the adhesive strength between the convex portion 21 and the conductive layer 11 can be increased.

  Further, as shown in FIG. 1B, the average particle size of the second inorganic insulating particles 17b included in the convex portions 21 is the second inorganic insulating layer included in the vicinity region 24 of the other main surface of the inorganic insulating layer 14. It is larger than the average particle size of the particles. As a result, by increasing the average particle size of the second inorganic insulating particles 17b included in the convex portion 21, the strength of the convex portion 21 can be further increased and the occurrence of cracks in the convex portion 21 can be further suppressed. Further, by reducing the average particle size of the second inorganic insulating particles 17b included in the neighboring region 24, the first inorganic insulating particles 17a are filled with high density and easily densified. A low coefficient of thermal expansion can be obtained.

  The average particle size of the second inorganic insulating particles 17b included in the convex portion 21 is, for example, 1 μm or more and 5 μm or less, and the average particle size of the second inorganic insulating particles 17b included in the vicinity region 24 is, for example, 0.1 μm or more. 2 μm or less. The near region 24 refers to a layered region having a distance of 2 μm or less from the other main surface of the inorganic insulating layer 14.

Moreover, as shown in FIG.1 (b), the average particle diameter of the 2nd inorganic insulating particle 17b of the inorganic insulating layer 14 is large toward the area | region by the side of the convex part 21 from the area | region of the other main surface side. As a result, the material characteristics inside the inorganic insulating layer 14 gradually change from the region on the other main surface side toward the region on the convex portion 21 side, so that, for example, when the inorganic insulating layer 14 is heated, the inorganic insulating layer 14 It can suppress that stress concentrates on a part of layer 14, and a crack arises.

  Moreover, as shown in FIG.1 (b), the convex part 21 contains the some 2nd inorganic insulating particle 17b. As a result, the strength of the convex portion 21 can be further increased and the occurrence of cracks in the convex portion 21 can be further suppressed.

  Moreover, as shown in FIG.1 (b), the convex part 21 is several 2nd inorganic insulating particle 17b arranged along the width direction (direction along the main surface direction of the inorganic insulating layer 14) of the convex part 21. As shown in FIG. Is included. As a result, by increasing the strength of the convex portion 21 in the width direction, it is possible to suppress the destruction of the convex portion 21 due to the stress along the main surface direction of the inorganic insulating layer 14.

  Further, as shown in FIG. 1B, the number of second inorganic insulating particles 17 b arranged along the width direction of the convex portion 21 in the convex portion 21 is the height direction (inorganic) of the convex portion 21 in the convex portion 21. More than the number of the second inorganic insulating particles 17b arranged along the direction perpendicular to the main surface direction of the insulating layer 14). As a result, by increasing the strength of the convex portion 21 in the width direction, it is possible to suppress the destruction of the convex portion 21 due to the stress along the main surface direction of the inorganic insulating layer 14.

  Further, as shown in FIG. 1B, the width of the convex portion 21 (width along the main surface direction of the inorganic insulating layer 14) is orthogonal to the height of the convex portion 21 (main surface direction of the inorganic insulating layer 14). Larger than the height to be. As a result, by increasing the strength of the convex portion 21 in the width direction, it is possible to suppress the destruction of the convex portion 21 due to the stress along the main surface direction of the inorganic insulating layer 14.

  The width of the convex portion 21 is, for example, 1 μm or more and 10 μm or less. Moreover, the height of the convex part 21 is 0.5 micrometer or more and 5 micrometers or less, for example. Moreover, the width | variety of the 1st recessed part 22a is 0.5 micrometer or more and 5 micrometers or less, for example. The width and height of the convex portion 21 can be measured by calculating the average value of the width and height of the convex portion 21 in the cross section in the thickness direction of the wiring board 3. The widths of the first concave portion 22a and other members are measured in the same manner as the width of the convex portion 21.

  In addition, as shown in FIG. 1B, the wiring board 3 further includes a resin layer 13 disposed in a region different from the conductive layer 11 on one main surface of the inorganic insulating layer 14. The one main surface further includes a second recess 22b that is located between the adjacent protrusions 21 and in which a part of the resin layer 13 is disposed. As a result, since a part of the resin layer 13 is disposed in the second recess 22b, the adhesive strength between the resin layer 13 and the inorganic insulating layer 14 can be increased by the anchor effect, and the resin layer 13 and the inorganic insulating layer can be increased. 14 can be prevented from peeling. Therefore, the occurrence of swelling and migration due to this peeling can be suppressed, and the electrical reliability of the wiring board 3 can be improved.

  Moreover, as shown in FIG. 1B, a part of the resin layer 13 disposed in the second recess 22 b includes filler particles 16. As a result, it is possible to reduce the difference in coefficient of thermal expansion between part of the resin layer 13 disposed in the second recess 22b and the inorganic insulating layer 14, and to increase the adhesive strength between the resin layer 13 and the inorganic insulating layer 14. .

  Next, the manufacturing method of the mounting structure 1 mentioned above is demonstrated based on FIG. 3 thru | or FIG.

  (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. 3B to 7A, for example, a support 25 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 25. A laminated sheet 27 including the insulating layer 14 and an uncured resin layer precursor 26 disposed on the inorganic insulating layer 14 is produced. Specifically, for example, the following is performed.

  First, as shown in FIGS. 3B to 4A, an inorganic insulating sol 29 having inorganic insulating particles 17 and a solvent 28 in which the inorganic insulating particles 17 are dispersed is prepared, and the inorganic insulating sol 29 is supported on the support. 25 applied to one main surface. Next, the solvent 28 is evaporated from the inorganic insulating sol 29 to leave the inorganic insulating particles 17 on the support 25. The remaining inorganic insulating particles 17 are in contact with each other at close locations. Next, as shown in FIG. 4B to FIG. 5B, the inorganic insulating layer 17 is heated by connecting the inorganic insulating particles 17 adjacent to each other at the adjacent locations. Form. Next, as shown in FIGS. 6A to 7A, a resin layer precursor 26 is laminated on the inorganic insulating layer 14, and the laminated inorganic insulating layer 14 and resin layer precursor 26 are arranged in the thickness direction. A part of the resin layer precursor 26 is filled in the gap 18 by heating and pressing. As a result, the laminated sheet 27 can be produced.

  Here, in the present embodiment, one main surface of the support 25 to which the inorganic insulating sol 29 is applied has a plurality of protrusions 30 and a recess 31 positioned between the protrusions 30. The width of the part 31 is larger than the average particle diameter of the second inorganic insulating particles 17b. After applying the inorganic insulating sol 29 to one main surface of the support 25, the inorganic insulating particles 17 are allowed to settle on the one main surface of the support 25 by gravity or centrifugal force. At this time, the first inorganic insulating particles 17 a and the second inorganic insulating particles 17 b settle and are arranged in the recess 31. Then, after the solvent 28 is evaporated, the inorganic insulating particles 17 are connected to form the inorganic insulating layer 14, thereby forming the first concave portion 22 a and the second concave portion 22 b having a shape corresponding to the protruding portion 30. The convex part 21 having a shape corresponding to the hollow part 31 is formed. As a result, the convex part 21 containing the 1st inorganic insulating particle 17a and the 2nd inorganic insulating particle 17b which were distribute | arranged to the hollow part 31 can be formed.

  For example, in the case of using an electrolytic copper foil as the support body 25, by appropriately adjusting the electroplating conditions and appropriately adjusting the shape of the recessed portion 31 of the support body 25, a plurality of second lines arranged in the width direction are arranged. The convex part 21 containing the 2 inorganic insulating particles 17b can be formed. Moreover, the convex part 21 in which the number of the 2nd inorganic insulating particles 17b arranged along the width direction is larger than the number of the 2nd inorganic insulating particles 17b arranged along the height direction can be formed. Moreover, the convex part 21 whose width | variety is larger than height can be formed.

  Further, the second inorganic insulating particles 17b having a non-uniform particle size are allowed to settle on one main surface of the support 25, whereby the average particle size of the second inorganic insulating particles 17b included in the convex portion 21 is set to the inorganic insulating layer 14. The average particle diameter of the second inorganic insulating particles included in the vicinity region 24 of the other main surface can be made larger. Moreover, the average particle diameter of the 2nd inorganic insulating particle 17b of the inorganic insulating layer 14 can be enlarged toward the area | region by the side of the convex part 21 from the area | region of the other main surface side. The standard deviation of the particle size of the second inorganic insulating particles 17b is, for example, not less than 0.1 and not more than 2.

  The content ratio of the inorganic insulating particles 17 in the inorganic insulating sol 29 is, for example, 10% to 50% by volume, and the content ratio of the solvent 28 in the inorganic insulating sol 29 is, for example, 50% to 90% by volume. The solvent 28 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 29 is dried by heating and air drying, for example. The drying temperature is, for example, 20 ° C. or more and less than the boiling point of the solvent 28, and the drying time is, for example, 20 seconds or more and 30 minutes or less.

  The heating temperature at the time of connecting the inorganic insulating particles 17 is not less than the boiling point of the solvent 28 and lower 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 17a have a small average particle size of 3 nm or more and 110 nm or less. Therefore, even at such a low temperature, the first inorganic insulating particles 17a and the first inorganic insulating particles 17a The second inorganic insulating particles 17b can be firmly connected. This is because, since the first inorganic insulating particles 17a are very small, the atoms of the first inorganic insulating particles 17a, especially the atoms on the surface, actively move. Therefore, even at such a low temperature, the first inorganic insulating particles 17a and It is presumed that the first inorganic insulating particles 17a and the second inorganic insulating particles 17b are firmly connected.

  Further, by heating at such a low temperature as described above, the first inorganic insulating particles 17a and the first inorganic insulating particles 17a and the second inorganic insulating particles 17a and the second inorganic insulating particles 17b are maintained while maintaining the particle shapes of the first inorganic insulating particles 17a and the second inorganic insulating particles 17b. The inorganic insulating particles 17b can be connected only in the proximity region. As a result, a neck structure can be formed in the connection portion 20 and the open pore gap 18 can be easily formed. Note that the temperature at which the first inorganic insulating particles 17a can be firmly connected is, for example, about 250 ° C. when the average particle size of the first inorganic insulating particles 17a is set to 110 nm or less. When the average particle diameter of the particles 17a is set to 15 nm or less, it is about 150 ° C.

  The pressure applied when the laminated inorganic insulating layer 14 and the resin layer precursor 26 are heated and pressurized is, for example, 0.5 MPa or more and 2 MPa or less, and the pressing time is, for example, 60 seconds or more and 10 minutes or less. The temperature is, for example, 80 ° C. or higher and 140 ° C. or lower. In addition, since this heating temperature is less than the curing start temperature of the resin layer precursor 26, the resin layer precursor 26 can be maintained in an uncured state.

  (3) As shown in FIGS. 7B to 10B, the laminated sheet 27 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. 7B, a laminated sheet 27 is laminated on the core substrate 5 while the resin layer precursor 26 is in contact with the core substrate 5, and the laminated core substrate 5 and laminated sheet 27 are arranged in the thickness direction. After the laminated sheet 27 is adhered to the core substrate 5 by heating and pressurizing, the resin layer precursor 26 of the laminated sheet 27 is heated at a temperature not lower than the curing start temperature and lower than the thermal decomposition temperature. The body 26 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 27 can be formed on the core substrate 5.

  Next, as shown in FIGS. 8A and 8B, the support 15 is chemically peeled from the inorganic insulating layer 14 using a ferric chloride solution or a copper chloride solution, and then laser processing or the like. Is used to form a via hole that penetrates the insulating layer 10 in the thickness direction and exposes the conductive layer 11. Next, smear (resin residue) generated in the via hole by laser processing is removed (desmear treatment). Next, as shown in FIGS. 9A and 9B, a desired layer 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 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.

  A part of the resin layer precursor 26 that has entered the gap 18 in the step (2) becomes a part of the resin layer 13 that has entered the gap 18 in this step, and becomes the resin portion 19. In addition, each condition at the time of heat-pressing the laminated | stacked core board | substrate 5 and the lamination sheet 27 is the same as that of the heat-pressing of a process (2).

  Here, in this embodiment, the convex part 21, the 1st recessed part 22a, and the 2nd recessed part 22b which were formed at the process (2) are exposed by peeling the support body 15 from the inorganic insulating layer 14. FIG. When the conductive layer 11 is formed on one main surface of the inorganic insulating layer 14 where the first concave portion 22a is exposed, the plating solution enters the first concave portion 22a, so that a part of the conductive layer 11 enters the first concave portion 22a. It will be in a state of being arranged.

Further, it is desirable to use a plasma desmear method for the desmear treatment. As a result, since the resin portion 19 disposed on the surface of the inorganic insulating layer 14 and the gap 18 is difficult to be removed on one main surface of the inorganic insulating layer 14, the first recess 22a and The second recess 22b can be left. This plasma desmear method is performed by RF plasma or microwave plasma using, for example, oxygen, nitrogen, argon, carbon tetrafluoride (CF ₄ ) or the like as a source gas, and the processing time is, for example, not less than 2 minutes and not more than 30 minutes. .

  (4) As shown in FIGS. 10A to 11, a laminated sheet 27 is laminated on the insulating layer 10 to further form the insulating layer 10, and the conductive layer 11 and the via conductor 12 are formed on the insulating layer 10. As a result, the build-up layer 6 is formed on the core substrate 5 to produce the wiring substrate 3. 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 FIGS. 10A and 10B, a laminated sheet 27 is laminated on the second insulating layer 10b while the resin layer precursor 26 is in contact with the second insulating layer 10b, and the second laminated layer is laminated. After the laminated sheet 27 is adhered to the second insulating layer 10b by heating and pressing the insulating layer 10b and the laminated sheet 27 in the thickness direction, the resin layer precursor 26 of the laminated sheet 27 has a thermal decomposition temperature equal to or higher than the curing start temperature. By heating at a temperature lower than that, the resin layer precursor 26 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 27 can be formed on the second insulating layer 10b. Next, as shown in FIG. 11, 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 26 flows when the laminated sheet 27 is adhered to the second insulating layer 10b, the resin layer precursor 26 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. The conditions for heating and pressurizing the laminated second insulating layer 10b and the laminated sheet 27 are the same as the heating and pressurization in the step (2).

  Here, in the present embodiment, when the laminated second insulating layer 10b and the laminated sheet 27 are heated and pressed in the thickness direction, the second recess exposed on one main surface of the inorganic insulating layer 14 of the second insulating layer 10b. A part of the resin layer precursor 26 enters 22b, and a part of the resin layer precursor 26 is cured, so that a part of the resin layer 13 is disposed in the second recess 22b.

  (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 embodiment, and various changes, improvements, combinations, and the like can be made without departing from the gist 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 embodiment of the present invention described above, 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.

  Further, in the above-described embodiment of the present invention, the build-up multilayer substrate including the core substrate 5 and the build-up layer 6 is cited as an example of the wiring substrate 3, but examples of the wiring substrate 3 are other than the build-up multilayer substrate. In addition, for example, a coreless substrate is also included.

  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 base body 7. In this case, the base 7 has a resin layer 13 and an inorganic insulating layer 14, and the buildup layer 6 has a conductive layer 11 and a resin layer 13 disposed on the inorganic insulating layer 14. In addition, a part of the conductive layer 11 enters the first recess 22 a of the inorganic insulating layer 14.

  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. It does not matter. In this case, in each insulating layer 10, a part of the conductive layer 11 may enter the first recess 22 a of the inorganic insulating layer 14.

  Further, in the above-described embodiment of the present invention, the evaporation of the solvent 28 and the heating of the inorganic insulating particles 17 are performed separately in the step (2), but these may be performed simultaneously.

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
17a 1st inorganic insulating particle 17b 2nd inorganic insulating particle 18 Space | gap 19 Resin part 20 Connection part of several inorganic insulating particles 21 Convex part 22a 1st recessed part 22b 2nd recessed part 23 Main part of an inorganic insulating layer 24 Main part of an inorganic insulating layer Region near other main surface 25 Support 26 Resin layer precursor 27 Laminated sheet 28 Solvent 29 Inorganic insulating sol 30 Protruding portion 31 Recessed portion

Claims (9)

An inorganic insulating layer, and a conductive layer partially disposed on one main surface of the inorganic insulating layer,
The inorganic insulating layer includes a plurality of first inorganic insulating particles partially connected to each other and a plurality of first inorganic insulating particles having an average particle size larger than that of the first inorganic insulating particles and spaced apart from each other with the first inorganic insulating particles interposed therebetween. Second inorganic insulating particles,
The one principal surface of the inorganic insulating layer is located between a plurality of convex portions including the first inorganic insulating particles and the second inorganic insulating particles and the adjacent convex portions, and a part of the conductive layer is It possesses a arranged first recess has,
The inorganic insulating layer further includes a resin portion disposed in a gap between the first inorganic insulating particles,
The wiring board , wherein the convex portion further includes the resin portion . An inorganic insulating layer, and a conductive layer partially disposed on one main surface of the inorganic insulating layer,
The inorganic insulating layer includes a plurality of first inorganic insulating particles partially connected to each other and a plurality of first inorganic insulating particles having an average particle size larger than that of the first inorganic insulating particles and spaced apart from each other with the first inorganic insulating particles interposed therebetween. Second inorganic insulating particles,
The one principal surface of the inorganic insulating layer is located between a plurality of convex portions including the first inorganic insulating particles and the second inorganic insulating particles and the adjacent convex portions, and a part of the conductive layer is A first recess disposed,
The wiring board, wherein the surface of the second inorganic insulating particle contained in the convex portion is covered with the first inorganic insulating particle. An inorganic insulating layer, and a conductive layer partially disposed on one main surface of the inorganic insulating layer,
The inorganic insulating layer includes a plurality of first inorganic insulating particles partially connected to each other and a plurality of first inorganic insulating particles having an average particle size larger than that of the first inorganic insulating particles and spaced apart from each other with the first inorganic insulating particles interposed therebetween. Second inorganic insulating particles,
The one principal surface of the inorganic insulating layer is located between a plurality of convex portions including the first inorganic insulating particles and the second inorganic insulating particles and the adjacent convex portions, and a part of the conductive layer is A first recess disposed,
An average particle size of the second inorganic insulating particles included in the convex portion is larger than an average particle size of the second inorganic insulating particles included in a region near the other main surface of the inorganic insulating layer. Wiring board. The wiring board according to claim 3 ,
The wiring board according to claim 1, wherein an average particle diameter of the second inorganic insulating particles of the inorganic insulating layer increases from the region on the other principal surface side toward the region on the convex portion side. The wiring board according to claim 1,
The said convex part contains the said some 2nd inorganic insulating particle, The wiring board characterized by the above-mentioned. The wiring board according to claim 5 ,
The wiring board, wherein the convex part includes a plurality of the second inorganic insulating particles arranged along the width direction of the convex part. The wiring board according to claim 6 ,
The number of the second inorganic insulating particles arranged in the convex portion along the width direction of the convex portion is larger than the number of the second inorganic insulating particles arranged in the convex portion along the height direction of the convex portion. A wiring board characterized by a large number. The wiring board according to any one of claims 1 to 7 ,
A resin layer disposed on a region different from the conductive layer on the one principal surface of the inorganic insulating layer;
The one main surface of the inorganic insulating layer further includes a second concave portion that is located between the adjacent convex portions and in which a part of the resin layer is disposed. A wiring board according to any one of claims 1 to 8, is mounted on the wiring board, mounting structure characterized by comprising an electrically connected electronic components to the conductive layer.

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