JP6001439B2 - Wiring board and mounting structure - Google Patents

Description

The present invention electronic device (e.g. various audio-visual equipment, home appliances, communications equipment, computer equipment and peripherals) to the wiring board and mounting structure are used to relate.

  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 describes a wiring board including an insulating layer made of a resin in which a filler is dispersed and a wiring layer (conductive layer) formed on the insulating layer. .

  In general, such a wiring board has a larger coefficient of thermal expansion than an electronic component, so if heat is applied to the mounting structure during mounting or operation of the electronic component, the difference in thermal expansion between the wiring board and the electronic component Thermal stress resulting from the above may be applied to the wiring board, causing the wiring board to warp. As a result, stress is applied to the connection portion between the wiring board and the electronic component, so that the connection reliability between the wiring board and the electronic component is lowered, and the electrical reliability of the mounting structure is likely to be lowered.

  Therefore, it is desired to provide a mounting structure excellent in electrical reliability.

JP 2010-10639 A

The present invention can provide excellent mounting structure in electrical reliability, to solve the above need by providing a wiring substrate and mounting structure.

A wiring board according to an aspect of the present invention includes a first insulating layer having a plurality of first particles made of zirconia partially connected to each other and a resin portion disposed in a gap between the first particles, and the first insulating layer. And a conductive layer disposed so as to be in contact with one main surface side of the insulating layer, and the first particles are exposed on the one main surface of the first insulating layer .

  A mounting structure according to an aspect of the present invention includes the above wiring board and an electronic component mounted on the wiring board.

  According to the wiring board according to one aspect of the present invention, the first insulating layer can make the wiring board have a low coefficient of thermal expansion and high rigidity, thereby reducing the warping of the wiring board during mounting or operation of the electronic component. As a result, a mounting structure having excellent electrical reliability can be obtained.

  According to the mounting structure according to one aspect 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 concerning 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). (A) is sectional drawing which expanded and showed R4 part of FIG.3 (b), (b) is sectional drawing which expanded and showed the slurry of Fig.4 (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 the powder layer 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 the inorganic insulation part of Fig.6 (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 Fig.7 (a) 1st insulating layer. . (A) And (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a). (A) And (b) is sectional drawing explaining the manufacturing process of the mounting structure shown to Fig.1 (a).

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

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

  The electronic component 2 is a semiconductor element such as an IC or LSI, and is flip-chip mounted on the wiring substrate 3 via bumps 4 made of a conductive material such as solder. The electronic component 2 is made of a semiconductor material such as silicon, germanium, gallium arsenide, gallium arsenide phosphorus, gallium nitride, or silicon carbide. 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 the main surface direction (XY plane direction) and the thickness direction (Z direction) of the electronic component 2 is, for example, 2 ppm / ° C. or more and 7 ppm / ° C. or less. 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 bump 4, and the other buildup layer 6 is connected to an external circuit via, for example, a solder ball (not shown). Connect with.

  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 have circuit patterns that 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. In addition, the via conductor 12 is formed in a column shape whose diameter decreases 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 first insulating layer 13 disposed on the side opposite to the core substrate 5 and a second insulating layer 14 disposed on the core substrate 5 side. The conductive layer 11 is disposed on a part of one main surface of the first insulating layer 13 opposite to the core substrate 5, and the other insulating part adjacent to the one main surface of the first insulating layer 13 is insulated. A part of the second insulating layer 14 of the layer 10 is disposed.

  The first insulating layer 13 has a conductive layer 11 disposed on a part of one main surface opposite to the core substrate 5, and functions as a support member for the conductive layer 11. The thickness of the first insulating layer 13 is, for example, 3 μm or more and 30 μm or less. The Young's modulus of the first insulating layer 13 is, for example, 10 GPa or more and 100 GPa or less. The coefficient of thermal expansion in the thickness direction and main surface direction of the first insulating layer 13 is, for example, 0 ppm / ° C. or more and 10 ppm / ° C. or less.

  As shown in FIGS. 1B to 2B, the first insulating layer 13 is separated from the plurality of first particles 15 made of zirconia partially connected to each other with the first particles 15 interposed therebetween. A plurality of second particles 16 made of an inorganic insulating material having an average particle size larger than that of the first particles 15 and an average particle size larger than that of the first particles 15 disposed between the second particles 16. It has a plurality of third particles 17 made of an inorganic insulating material, which are smaller than the two particles 16, and a resin portion 18 disposed in the gap G between the first particles 15. The first particles 15, the second particles 16, and the third particles 17 constitute an inorganic insulating portion 19 in the first insulating layer 13.

  The first particles 15 are partially connected to each other to form a porous body in which gaps G are formed, and have a three-dimensional network structure. In the present embodiment, the connecting portion 20 between the first particles 15 is constricted and has a neck structure. The first particles 15 made of zirconia may contain 90% by mass or more of zirconia as a main component, and may contain impurities. The first particles 15 are, for example, spherical. The average particle size of the first particles 15 is preferably 20 nm or less, and more preferably 1 nm or more and 20 nm or less. The thermal expansion coefficient in each direction of the first particles 15 is 8 ppm / ° C. or more and 12 ppm / ° C. or less, and the Young's modulus of the first particles 15 is 180 GPa or more and 220 GPa or less. Moreover, the content rate of the 1st particle | grains 15 in the inorganic insulating part 19 is 5 volume% or more and 40 volume% or less, for example.

The average particle diameter of the first particles 15 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 particles 15 in the inorganic insulating portion 19 is determined in the inorganic insulating portion 1 in the cross section in the thickness direction of the wiring board 3.
9, the ratio of the area occupied by the first particles 15 can be measured as the content ratio (volume%). Hereinafter, the average particle diameter and the content ratio of each member are measured in the same manner as the first particles 15.

  The second particles 16 are made of, for example, an inorganic insulating material such as silicon oxide or cordierite, and are preferably made of silicon oxide. The second particles 16 made of silicon oxide need only contain 90% by mass or more of silicon oxide as a main component, and may contain impurities. The second particles 16 are, for example, spherical. The average particle diameter of the second particles 16 is desirably 0.5 μm or more and 5 μm or less. The thermal expansion coefficient in each direction of the second particles 16 is 0 ppm / ° C. or more and 10 ppm / ° C. or less, and the Young's modulus of the second particles 16 is 10 GPa or more and 50 GPa or less. Moreover, the content rate of the 2nd particle | grains 16 in the inorganic insulating part 19 is 50 volume% or more and 90 volume% or less, for example.

  The third particles 17 are preferably made of silicon oxide. The third particles 17 made of silicon oxide need only contain 90% by mass or more of silicon oxide as a main component, and may contain impurities. The third particles 17 are, for example, spherical. The average particle size of the third particles 17 is desirably 30 nm or more and 100 nm or less, and more desirably 30 nm or more and 60 nm or less. The thermal expansion coefficient and Young's modulus of the third particle 17 are the same as those of the second particle 16. Moreover, the content rate of the 3rd particle | grains 17 in the inorganic insulating part 19 is 5 volume% or more and 45 volume% or less, for example.

  The gap G is an open pore and has an opening on the other main surface of the first insulating layer 13. In addition, since the first particles 15 form a porous body and have a three-dimensional network structure, at least a part of the gap G is the first cross section in the thickness direction of the first insulating layer 13. Surrounded by one particle 15. In this gap G, a resin portion 18 in which a part of the second insulating layer 14 enters is disposed. In addition, the content rate of the resin part 18 in the 1st insulating layer 13 is 10 volume% or more and 50 volume% or less, for example.

  The second insulating layer 14 functions as an adhesive member in the insulating layer 10. The second insulating layer 14 is partly 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. It is. Further, since the second insulating layer 14 has a Young's modulus smaller than that of the first insulating layer 13 and is easily elastically deformed, the generation of cracks in the wiring substrate 3 is suppressed. The thickness of the second insulating layer 14 is, for example, 3 μm or more and 30 μm or less. The Young's modulus of the second insulating layer 14 is, for example, not less than 0.2 GPa and not more than 20 GPa. The coefficient of thermal expansion in the thickness direction and the main surface direction of the second insulating layer 14 is, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

  As shown in FIG. 1B, the second insulating layer 14 includes a resin 21 and a plurality of filler particles 22 dispersed in the resin 21.

  The resin 21 functions as an adhesive member in the second insulating layer 14. As the resin 21, 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 21 is, for example, 0.1 GPa or more and 5 GPa or less. The thermal expansion coefficient in the thickness direction and the main surface direction of the resin 21 is, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

The filler particles 22 make the second insulating layer 14 have a low coefficient of thermal expansion and high rigidity. The filler particles 22 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 22 is, for example, not less than 0.5 μm and not more than 5 μm. The thermal expansion coefficient of the filler particles 22 is, for example, not less than 0 ppm / ° C. and not more than 15 ppm / ° C. The content rate of the filler particle 22 in the 2nd insulating layer 14 is 3 volume% or more and 60 volume% or less, for example.

  Here, in the present embodiment, as shown in FIGS. 1B to 2B, the first insulating layer 13 includes a plurality of first particles 15 made of zirconia partially connected to each other, And a resin portion 18 disposed in the gap G between the particles 15.

  As a result, the plurality of first particles 15 made of zirconia having a lower thermal expansion coefficient and a higher Young's modulus than the resin part 18 are partially connected to each other and restrained. Since the first insulating layer 13 does not flow like the filler particles 22 dispersed in the first insulating layer 21, the first insulating layer 13 can have a low thermal expansion coefficient and high rigidity, and as a result, the wiring board 3 can have a low thermal expansion coefficient and high rigidity.

  Therefore, by making the wiring board 3 have a low coefficient of thermal expansion, the difference in the coefficient of thermal expansion between the wiring board 3 and the electronic component 2 is reduced to reduce the thermal stress applied to the wiring board 3 and to make the wiring board 3 highly rigid. By doing so, the wiring board 3 can be made difficult to warp against thermal stress. Therefore, it is possible to reduce the warpage of the wiring board 3 during mounting and operation of the electronic component 2 and to improve the connection reliability between the wiring board 3 and the electronic component 2, so that the mounting structure is excellent in electrical reliability. The body 1 can be obtained. Further, by reducing the warp of the wiring board 3 when the electronic component 2 is mounted, it is possible to reduce defects when the wiring board 3 is mounted on the electronic component 2.

  Moreover, since the several 1st particle | grains 15 are comprised from the zirconia whose Young's modulus is higher than inorganic insulating materials, such as a silicon oxide, the 1st insulating layer 13 can be made highly rigid. As a result, when thermal stress or mechanical stress is applied to the first insulating layer 13, the generation of cracks in the first insulating layer 13 is reduced, and the disconnection of the conductive layer 11 due to the cracks is suppressed. it can.

  On the other hand, since the resin portion 18 that is more elastically deformed than the first particles 15 is disposed in the gap G between the first particles 15, stress applied to the first insulating layer 13 is relieved. Generation of cracks in the layer 13 can be suppressed.

  Further, as shown in FIGS. 1B to 2B, the wiring board 3 of the present embodiment is in contact with the inner wall of the via hole V (through hole) penetrating the first insulating layer 14 in the thickness direction. In addition, a via conductor 12 (through conductor) connected to the conductive layer 11 is provided, and the first particles 15 are exposed on the inner wall of the via hole V. As a result, since the first particles 15 exposed on the inner wall of the via hole V are made of zirconia having higher chemical resistance than, for example, silicon oxide or the like, the first particles 15 caused by chemicals when forming the via conductor 12 are formed. It is possible to suppress the breakage of the connecting portions 20 and to strengthen the connecting portions 20. Further, the inner wall of the via hole V has a plurality of first convex portions 23 made of a part of the exposed first particles 15.

  Further, the inner wall of the via hole V has a plurality of second convex portions 24 made of a part of the exposed second particles 16. As a result, the adhesive strength between the inner wall of the via hole V and the via conductor 12 can be increased by the anchor effect. Moreover, since the chemical resistance of the first particles 15 is high, the bonding strength between the inner wall of the via hole V and the second convex portion 24 can be increased by strengthening the connection portion 20 between the first particles 15. The anchor effect described above can be enhanced.

Further, the inner wall of the via hole V has a plurality of third convex portions 25 made of a part of the exposed third particles 17. As a result, the adhesive strength between the inner wall of the via hole V and the via conductor 12 can be increased by the anchor effect. Moreover, since the chemical resistance of the first particles 15 is high, the bonding strength between the inner wall of the via hole V and the third convex portion 25 can be increased by strengthening the connection portion 20 between the first particles 15. The anchor effect described above can be enhanced.

  The conductive layer 11 is in contact with one main surface of the first insulating layer 13, and the first particles 15 are exposed on the one main surface of the first insulating layer 13. As a result, since the first particles 15 exposed on one main surface of the first insulating layer 13 are made of zirconia having higher chemical resistance than, for example, silicon oxide, the first particles 15 are caused by chemicals when forming the conductive layer 11. Breakage of the connection part 20 between the first particles 15 can be suppressed. Therefore, since the adhesive strength between the one main surface of the first insulating layer 13 and the conductive layer 11 can be increased, the conductive layer 11 caused by the peeling between the one main surface of the first insulating layer 13 and the conductive layer 11 can be improved. Disconnection can be reduced.

  In addition, the wiring board 3 of the present embodiment includes a resin 21 and filler particles 22 dispersed in the resin 21, and includes a second insulating layer 14 disposed on the other main surface side of the first insulating layer 13, A part of the second insulating layer 14 enters the resin portion 18. As a result, the occurrence of cracks in the first insulating layer 13 can be suppressed by the resin portion 18 as described above. Furthermore, since a part of the second insulating layer 14 enters the gap G of the first insulating layer 13, the adhesive strength between the first insulating layer 13 and the second insulating layer 14 can be increased by the anchor effect. Therefore, since the peeling between the first insulating layer 13 and the second insulating layer 14 can be suppressed, the heat is applied to the wiring board 3 during mounting or operation of the electronic component 2 and is included in the wiring board 3. It is possible to suppress the generated moisture from expanding at the peeled portion, and to suppress the occurrence of cracks due to the expansion at the peeled portion. Therefore, disconnection of the conductive layer 11 due to this crack and short circuit due to ion migration can be suppressed.

  In addition, the first insulating layer 13 includes a plurality of second particles 16 made of an inorganic insulating material and having an average particle size larger than that of the first particles 15 and spaced apart from each other with the first particles 15 interposed therebetween. As a result, since the average particle diameter of the second particles 16 is large, the cracks generated in the first insulating layer 13 increase the energy for bypassing the second particles 16, so that the extension of the cracks can be suppressed. . In addition, since the plurality of second particles 16 are generally made of an inorganic insulating material having higher hardness than a resin material or the like, it is possible to further suppress the extension of cracks.

  The second particles 16 are preferably made of silicon oxide. As a result, since silicon oxide has a lower dielectric loss tangent and a lower dielectric constant than zirconia, the signal transmission characteristics of the wiring board 3 can be improved. Moreover, since silicon oxide has a low coefficient of thermal expansion compared to zirconia, the wiring board 3 can have a low coefficient of thermal expansion.

  The first insulating layer 13 includes a plurality of third particles made of an inorganic insulating material, which are disposed between the second particles 16 and have an average particle size larger than the first particles 15 and smaller than the second particles 16. 17. As a result, the third particles 17 having an average particle size smaller than the second particles 16 can be arranged between the second particles 16. Furthermore, since the average particle size of the third particles 17 is larger than the average particle size of the first particles 15, the cracks generated in the first insulating layer 13 increase the energy for bypassing the third particles 17, The extension of cracks between the second particles 16 can be suppressed. Moreover, since the 3rd particle | grains 17 consist of an inorganic insulating material, it can suppress the expansion | extension of a crack more.

  The third particles 17 are preferably made of silicon oxide. As a result, the signal transmission characteristics of the wiring board 3 can be improved and the wiring board 3 can have a low coefficient of thermal expansion.

  It is desirable that the third particles 17 are partially connected to each other. As a result, the plurality of third particles 17 made of an inorganic insulating material generally having a lower coefficient of thermal expansion and a higher Young's modulus than the resin material are partially connected to each other and restrained, so that the first insulating layer 13 Can have a lower thermal expansion coefficient and higher rigidity.

  The average particle size of the first particles 15 is desirably 20 nm or less. As a result, since the average particle diameter of the first particles 15 is very small, the first insulating layer 13 can be made dense so as to have a high rigidity and a low coefficient of thermal expansion. The first particles 15 can be easily connected to each other when producing the above.

  The average particle diameter of the second particles 16 is desirably 0.5 μm or more and 5 μm or less. As a result, since the average particle diameter of the second particles 16 is large, the extension of cracks in the first insulating layer 13 can be further suppressed.

  The average particle size of the third particles 17 is desirably 30 nm or more and 100 nm or less. As a result, the third particles 17 can be favorably arranged between the second particles 16, and the extension of cracks between the second particles 16 can be further suppressed. Moreover, since the average particle diameter of the 3rd particle | grains 17 is 100 nm or less, when producing the 1st insulating layer 13, 2nd particle | grains 16 can be easily connected so that it may mention later.

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

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

  A laminated plate made of a base 7 formed by curing the prepreg and a metal foil such as copper disposed above and below the base 7 is prepared. Next, through-holes are formed in the laminate using sandblasting, laser processing, or drilling. 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 7B, for example, a support 26 made of a metal foil such as copper foil, a first insulating layer 13 disposed on the support 26, and a first A laminated sheet 28 including an uncured resin layer precursor 27 disposed on the insulating layer 13 is produced. Specifically, for example, the following is performed.

  First, as shown in FIGS. 3B to 4B, the first particles 15, the second particles 16, the third particles 17, and the particles 15 to 17 (the first particles 15 to the third particles 17) are formed. A slurry 30 having a dispersed solvent 29 is prepared, and the slurry 30 is applied to one main surface of the support 26. Next, as shown in FIGS. 5A and 5B, the solvent 26 is evaporated from the slurry 30 to leave the particles 15 to 17 on the support 26, and the powder made of the particles 15 to 17. Layer 31 is formed. The remaining particles 15 to 17 are in contact with each other at close locations. Next, as shown in FIG. 6A and FIG. 6B, the remaining particles 15 to 17 are heated to connect the adjacent first particles 15 to each other at adjacent locations, thereby allowing the inorganic insulating portion 19 to be connected. Form. Next, as shown in FIGS. 7A and 7B, a resin layer precursor 27 is laminated on the first insulating layer 13, and the laminated first insulating layer 13 and resin layer precursor 27 are bonded. A part of the resin layer precursor 27 is filled in the gap G by heating and pressing in the thickness direction. As a result, the laminated sheet 28 can be produced.

  The content ratio of the solvent 26 in the slurry 30 is, for example, 50% to 90% by volume. The solvent 26 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 slurry 30 is dried when the solvent 26 is evaporated, for example, by heating and air drying. The drying temperature is, for example, 20 ° C. or higher and lower than the boiling point of the solvent 26, and the drying time is, for example, 20 seconds or longer and 30 minutes or shorter.

  Here, in this embodiment, since the gap between the particles 15 to 17 in the slurry 30 can be reduced by the second particles 16 having an average particle size larger than that of the first particles 15, the powder layer formed by evaporating the solvent 26. 31 shrinkage can be reduced. Therefore, the occurrence of cracks along the thickness direction of the powder layer 31 can be reduced by reducing the shrinkage of the powder layer 31 that is flat and easily contracts in the main surface direction. Even if a crack occurs in the powder layer 31, the extension of the crack can be suppressed by the second particles 16 having an average particle diameter larger than that of the first particles 15.

  In the present embodiment, since the third particles 17 having an average particle size larger than the first particles 15 and smaller than the second particles 16 are arranged between the second particles 16, the second particles of the slurry 30. The gap between the particles 15 to 17 between the particles 16 can be further reduced, and the shrinkage between the second particles 16 of the powder layer 31 can be reduced. As a result, the generation of cracks between the second particles 16 of the powder layer 31 can be reduced. Even if a crack occurs between the second particles 16 of the powder layer 31, the extension of the crack can be suppressed by the third particles 17 having an average particle diameter larger than that of the first particles 15.

  The heating temperature when connecting the first particles 15 is desirably 100 ° C. or higher and 250 ° C. or lower. The heating time is preferably 0.5 hours or more and 24 hours or less.

  Here, in this embodiment, when the average particle diameter of the first particles 15 is as small as 20 nm or less, the first particles 15 are connected even when the heating temperature is 100 ° C. or higher and 250 ° C. or lower. Can do. This is presumed that since the first particles 15 are very small, the atoms of the first particles 15, particularly the atoms on the surface, actively move, so that the first particles 15 are firmly connected even at such a low temperature. The The temperature at which the first particles 15 can be connected to each other is, for example, about 150 ° C. when the average particle size of the first particles 15 is set to 20 nm or less, and the average particle size of the first particles 15 is further reduced. By doing so, the temperature can be further lowered.

  Further, by heating at such a low temperature in this way, the first particles 15 can be connected to each other only in the proximity region while maintaining the particle shape of the first particles 15. As a result, a neck structure can be formed in the connection portion 20 and the open pore gap G can be easily formed. Moreover, by heating at low temperature in this way, the thermal stress added to the connection of the 1st particle | grains 15 can be reduced, and generation | occurrence | production of the crack by a thermal stress can be suppressed.

In addition, if the average particle diameter of the third particles 17 is as small as 100 nm or less, the third particles 17 can be connected to each other even at such a low temperature. This is presumed to be due to the same reason as the first particles 15. In order to connect the third particles 17 in this way, it is desirable to use the third particles 17 made of silicon oxide. The temperature at which the third particles 17 can be connected is, for example, about 250 ° C. when the average particle size of the third particles 17 is set to 100 nm or less.

  The pressure applied when the first insulating layer 13 and the resin layer precursor 27 thus laminated 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 heating 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 27, the resin layer precursor 27 can be maintained in an uncured state.

  (3) As shown in FIGS. 8A and 8B, a laminated sheet 28 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. 8A, a laminated sheet 28 is laminated on the core substrate 5 while the resin layer precursor 27 is in contact with the core substrate 5, and the laminated core substrate 5 and laminated sheet 28 are arranged in the thickness direction. After the laminated sheet 28 is adhered to the core substrate 5 by heating and pressing, the resin layer precursor 27 is cured by heating at a temperature not lower than the curing start temperature of the resin layer precursor 27 and lower than the thermal decomposition temperature. Thus, the second insulating layer 14 is formed. At this time, a part of the resin layer precursor 27 that has entered the gap G becomes the resin portion 18 disposed in the gap G. Next, as shown in FIG. 8B, for example, the first insulating layer 13 to the support 15 are etched by an etching method using a first chemical such as an etching solution such as a ferric chloride solution or a copper chloride solution and a cleaning solution. Then, via holes V that penetrate the insulating layer 10 in the thickness direction and expose the conductive layer 11 are formed by laser processing or the like. Next, smear (resin residue) generated in the via hole by laser processing or the like is removed by a wet desmear method using a second chemical such as a desmear solution such as a permanganic acid solution (desmear treatment). Next, a conductive layer 11 having a desired pattern is formed on the insulating layer 10 and a via conductor 12 is formed in the via hole V by a semi-additive method using an electroless plating method and an electroplating method. In this semi-additive method, for example, an etching solution such as a ferric chloride solution or a copper chloride solution and a third chemical such as a plating solution are used.

  In addition, each condition at the time of heat-pressing the laminated | stacked core board | substrate 5 and the lamination sheet 28 is the same as that of the heat-pressing of a process (2).

  By the way, when the treatment with the first chemical or the third chemical is performed, the first chemical or the third chemical touches the first particles 15 exposed on the first main surface of the first insulating layer 13 or the inner wall of the via hole V. If the first chemical or the third chemical dissolves the first particles 15, the connecting portions 20 of the first particles 15 are destroyed, and the conductive layer 11 is easily peeled off from the first main surface of the first insulating layer 13. In addition, the via conductor 12 is easily peeled from the inner wall of the via hole V. In particular, the second chemical easily dissolves various materials.

  On the other hand, in this embodiment, since the 1st particle 15 consists of zirconia with high chemical resistance, since dissolution of the 1st particle 15 by the 1st medicine thru / or the 3rd medicine can be controlled, the 1st particles 15 mutually The connection part 20 can be prevented from being broken and the connection part 20 can be strengthened.

  In the present embodiment, since the via hole V is formed by laser processing, a part of the particles 15 to 17 protrudes from the inner wall of the via hole V, and the first to third protrusions 23 to 25. Can be formed.

As conditions for such laser processing, for example, the following conditions can be used. When a carbon dioxide laser (wavelength: 10.6 μm) is used, the energy per pulse (shot) of the laser beam is set to, for example, 20 mJ (millijoule) or more and 100 mJ or less,
The pulse width of the laser light may be set to, for example, 10 μs (microseconds) to 200 μs, and the number of shots of the laser light may be set to, for example, 1 to 5.

  When using a YAG laser (wavelength: 355 nm), the energy per pulse (shot) is, for example, 20 μJ (microjoules) to 100 μJ, and the pulse width of the laser light is, for example, 5 ns (nanoseconds) to 200 ns. For example, the number of shots of laser light may be 3 or more and 20 or less.

  (4) As shown in FIGS. 9A and 9B, a laminated sheet 28 is laminated on the insulating layer 10 to further form the insulating layer 10, and the conductive layer 11 and the via conductor are formed on the insulating layer 10. By forming 12, the build-up layer 6 is formed on the core substrate 5, and the wiring substrate 3 is produced. Specifically, for example, the following is performed.

  First, as shown in FIG. 9A, a laminated sheet 28 is laminated on the insulating layer 10 while the resin layer precursor 27 is in contact with the insulating layer 10, and the laminated insulating layer 10 and laminated sheet 28 are arranged in the thickness direction. After the laminated sheet 28 is bonded to the insulating layer 10 by heating and pressing, the resin layer precursor 27 is cured by heating the resin layer precursor 27 at a temperature not lower than the curing start temperature and lower than the thermal decomposition temperature. Thus, the second insulating layer 14 is obtained. As a result, the insulating layer 10 can be further formed on the insulating layer 10. Next, as shown in FIG. 9B, a conductive layer 11 and a via conductor 12 are formed on the newly formed insulating layer 10 by the same method as in the step (3). In addition, the build-up layer 6 can be multi-layered by repeating this process.

  (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 electronic component 2 may be electrically connected to the wiring board 3 by wire bonding, or may be incorporated in the wiring board 3.

  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 embodiment of the present invention, the configuration in which the insulating material according to the present invention is used as the first insulating layer 13 of the wiring board 3 is described as an example. As long as it has the some 1st particle | grains 15 which consist of the connected zirconia, and the resin part 18 distribute | arranged to the gap | interval G between 1st particle | grains 15, you may use for another use. For example, the insulating material according to the present invention may be used as a magnetic material. In this case, the fourth particles 16 made of a magnetic material such as ferrite may be used instead of the second particles 16 described above. The configuration of the fourth particles can be the same as the configuration of the second particles 16, for example, and the configuration other than the fourth particles can be the same as the configuration of the first insulating layer 13, for example.

  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 given as an example of the wiring substrate 3. However, the wiring substrate 3 is not limited to the build-up multilayer substrate. For example, a substrate having another configuration such as a coreless substrate is also included.

  In the above-described embodiment of the present invention, the configuration in which the first insulating layer 13 is applied to the buildup layer 6 has been described as an example. However, the first insulating layer 13 may be applied to the base body 7. In this case, the structure of the inner wall of the through hole (through hole) may be the same as the structure of the inner wall of the via hole V described above.

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

  In the embodiment of the present invention described above, the configuration in which the conductive layer 11 is in contact with one main surface of the first insulating layer 13 has been described as an example. However, the one main surface of the first insulating layer 13 and the conductive layer 11 A resin layer or the like may be interposed between them.

  In the above-described embodiment of the present invention, the configuration in which the inorganic insulating portion 19 includes the first particle 15 to the third particle 17 has been described as an example. However, the inorganic insulating portion 19 includes at least the first particle 15. The second particles 16 or the third particles 17 may not be included, or other particles may be included.

  Moreover, in embodiment of this invention mentioned above, although the structure using the support body 26 which consists of metal foils was demonstrated to the example in process (2), even if it uses the support body 16 which consists of resin sheets, such as PET film. I do not care.

  In the above-described embodiment of the present invention, the configuration in which the evaporation of the solvent 26 and the heating of the remaining particles 15 to 17 are separately performed in the step (2) has been described as an example. I do not care.

  In the above-described embodiment of the present invention, the configuration in which the support 26 is chemically peeled in the step (2) has been described as an example. However, the support 26 may be mechanically peeled off.

  Further, in the above-described embodiment of the present invention, the configuration in which the conductive layer 11 and the via conductor 12 are formed using the semi-additive method in the step (3) has been described as an example. However, the conductive layer 11 is electrically conductive by the subtractive method or the full additive method. Layer 11 and via conductor 12 may be formed.

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 1st insulating layer 14 2nd insulating layer 15 1st Particle 16 Second particle 17 Third particle 18 Resin part 19 Insulating part 20 Connection part between first particles 21 Resin 22 Filler particle 23 First convex part 24 Second convex part 25 Third convex part 26 Support body 27 Resin layer Precursor 28 Laminated sheet 29 Solvent 30 Slurry 31 Powder layer G Gap V Via hole

Claims (7)

A plurality of first particles made of zirconia partially connected to each other and a first insulating layer having a resin portion disposed in a gap between the first particles, so as to be in contact with one main surface side of the first insulating layer A wiring layer, wherein the first particles are exposed on the one main surface of the first insulating layer . The wiring board according to claim 1,
And further comprising a through conductor in contact with the inner wall of the through hole penetrating the first insulating layer in the thickness direction and connected to the conductive layer,
The wiring board, wherein the first particles are exposed on the inner wall of the through hole. The wiring board according to claim 1,
A resin and filler particles dispersed in the resin, further comprising a second insulating layer disposed on the other main surface side of the first insulating layer;
The wiring board according to claim 1, wherein a part of the second insulating layer enters the resin portion. The wiring board according to claim 1,
The first insulating layer further includes a plurality of second particles made of an inorganic insulating material and having an average particle size larger than the first particles and spaced apart from each other with the first particles interposed therebetween. . The wiring board according to claim 4 ,
The first insulating layer further includes a plurality of third particles made of an inorganic insulating material, which are disposed between the second particles and have an average particle size larger than the first particles and smaller than the second particles. A wiring board comprising: The wiring board according to claim 5 ,
The average particle diameter of the first particles is 20 nm or less,
The average particle diameter of the second particles is 0.5 μm or more and 5 μm or less,
An average particle diameter of the third particles is 30 nm to 100 nm.   A mounting structure comprising the wiring board according to claim 1 and an electronic component mounted on the wiring board.

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