JP5909528B2 - Wiring board, laminated board and laminated sheet - Google Patents

Description

  The present invention relates to a wiring board, a laminate, and a laminate sheet used for electronic devices (for example, various audiovisual devices, home appliances, communication devices, computer devices, and peripheral devices thereof).

  2. Description of the Related Art Conventionally, as a mounting structure in an electronic device, an electronic component mounted on a wiring board is used.

  Japanese Patent Application Laid-Open No. 4-12087 discloses a wiring board including a resin layer, an inorganic insulating layer provided on the upper surface of the resin layer, and a conductive layer provided on the upper surface of the inorganic insulating layer.

  By the way, generally, since an inorganic insulating layer is more susceptible to cracking than a resin layer, when stress is applied to the wiring board, the inorganic insulating layer is likely to crack, and the crack is in the thickness direction of the inorganic insulating layer. May stretch along. As a result, the electrical reliability of the wiring board tends to decrease.

Japanese Patent Laid-Open No. 4-122087

  The present invention provides a wiring board, a laminate, and a laminate sheet that meet the demand for improving electrical reliability.

A laminated sheet according to an embodiment of the present invention includes a support member and an inorganic insulating layer disposed on the support member and having a groove penetrating in the thickness direction, and the inorganic insulating layers are bonded to each other. And having a plurality of inorganic insulating particles .

A laminate according to one aspect of the present invention includes a pair of inorganic insulating layers having grooves penetrating in the thickness direction, and a resin layer disposed between the inorganic insulating layers, and the inorganic insulating layers are It has a plurality of bonded inorganic insulating particles .

A wiring board according to an embodiment of the present invention includes a resin layer and an inorganic insulating layer that is disposed on the resin layer and has a groove that penetrates in the thickness direction, and the inorganic insulating layers are bonded to each other. that having a plurality of inorganic insulating particles.

  According to the said structure, the wiring board, laminated board, and laminated sheet which improved electrical reliability can be provided.

FIG. 1A is a cross-sectional view of a mounting structure according to an embodiment of the present invention cut in a vertical direction, and FIG. 1B schematically shows a state in which two inorganic insulating particles are combined. 2A is an enlarged cross-sectional view of the R1 portion of the mounting structure shown in FIG. 1A, and FIG. 2B is a cross-sectional view taken along the line I-I in FIG. 2A. FIG. 3 is an enlarged cross-sectional view of the R2 portion of the mounting structure shown in FIG. 1A. 4A is a cross-sectional view taken along the vertical direction for explaining a manufacturing process of the mounting structure shown in FIG. 1A, and FIG. 4B is an enlarged cross-sectional view of the R3 portion of FIG. 4A. 5A is a cross-sectional view taken along the vertical direction for explaining a manufacturing process of the mounting structure shown in FIG. 1A, and FIG. 5B is an enlarged cross-sectional view of the R4 portion of FIG. 5A. 6A, 6B, and 6D are cross-sectional views cut in the vertical direction for explaining the manufacturing process of the mounting structure shown in FIG. 1A, and FIG. 6C is an enlarged cross-sectional view of the portion R5 in FIG. 6B. It is. 7A and 7C are cross-sectional views cut in the vertical direction for explaining the manufacturing process of the mounting structure shown in FIG. 1A, and FIG. 7B is an enlarged cross-sectional view of the R6 portion shown in FIG. 7B. . FIG. 8A is a cross-sectional view taken along the vertical direction for explaining a manufacturing process of the mounting structure shown in FIG. 1A, and FIG. 8B is an enlarged cross-sectional view of the R7 portion shown in FIG. 8B. FIG. 9 is a cross-sectional view taken in the vertical direction for explaining a manufacturing process of the mounting structure shown in FIG. 1A. 10A is a cross-sectional view in which a mounting structure according to another embodiment of the present invention is cut in the vertical direction, and is a cross-sectional view showing an enlarged portion corresponding to the R1 portion of FIG. 1A. FIG. It is the photograph which image | photographed a part of cross section which cut | disconnected the laminated board of the Example to the up-down direction with the field emission electron microscope. FIG. 11A is a photograph in which a part of a cross section of the laminate of the example cut in the vertical direction is taken with a field emission electron microscope, and FIG. 11B is an enlarged photograph of the R8 portion of FIG. 11A.

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

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

  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 base material of the electronic component 2 is formed of a semiconductor material such as silicon, germanium, gallium arsenide, gallium arsenide phosphorus, gallium nitride, or silicon carbide. As the electronic component 2, for example, an average thickness value, that is, a thickness of 0.1 mm or more and 1 mm or less can be used.

  The wiring substrate 3 includes a core substrate 5 and a pair of wiring layers 6 formed on the upper and lower surfaces of the core substrate 5.

  The core substrate 5 is for increasing the rigidity of the wiring substrate 3. The core substrate 5 includes a base body 7, a through hole T, a through hole conductor 8, and an insulator 9.

  The base 7 increases the rigidity of the core substrate 5 and includes a first resin layer 10a and first inorganic insulating layers 11a provided on the upper and lower surfaces of the first resin layer 10a.

The first resin layer 10a is a main part of the base 7, and includes, for example, a resin part and a base material covered with the resin part. The first resin layer 10a has a thickness set to, for example, 0.1 mm to 3.0 mm, a Young's modulus set to, for example, 0.2 GPa to 20 GPa, and a thermal expansion coefficient in the plane direction, for example, 3 ppm / ° C. to 20 ppm. The coefficient of thermal expansion in the thickness direction is set to, for example, 30 ppm / ° C. or more and 50 ppm / ° C. or less, and the dielectric loss tangent is set to, for example, 3 or more and 4 or less. Here, the Young's modulus conforms to JISC5600: 2006, the thermal expansion coefficient conforms to ISO11359-2: 1999, and the dielectric loss tangent conforms to JISK6911: 1995.

  The resin portion of the first resin layer 10a can be formed of, for example, a thermosetting resin such as an epoxy resin, a bismaleimide triazine resin, a cyanate resin, a polyphenylene ether resin, a wholly aromatic polyamide resin, or a polyimide resin. The resin part has a Young's modulus set to, for example, 0.1 GPa or more and 5 GPa or less, and a coefficient of thermal expansion in a plane direction or a thickness direction is set to, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

  The base material contained in the first resin layer 10a reduces the coefficient of thermal expansion of the first resin layer 10a and increases the rigidity of the first resin layer 10a. The base material can be formed by, for example, a woven or non-woven fabric composed of a plurality of fibers, or a fiber bundle in which fibers are arranged in one direction. As said fiber, glass fiber, a resin fiber, carbon fiber, a metal fiber etc. can be used, for example.

  The first resin layer 10a preferably contains the first inorganic insulating filler 12a. As a result, the coefficient of thermal expansion of the first resin layer 10a can be reduced and the rigidity of the first resin layer 10a can be increased. The first inorganic insulating filler 12a can be formed of an inorganic insulating material such as silicon oxide, aluminum oxide, aluminum nitride, aluminum hydroxide, or calcium carbonate. The particle diameter of the first inorganic insulating filler 12a is set to, for example, 0.2 μm to 3 μm, and the coefficient of thermal expansion is set to, for example, 0 ppm / ° C. to 15 ppm / ° C. The first inorganic insulating filler 12a is such that the volume ratio of the first inorganic insulating filler 12a to the total volume of the resin portion of the first resin layer 10a and the first inorganic insulating filler 12a is, for example, 3% by volume to 60% by volume. Is set.

  For example, as shown in FIG. 1B, the first inorganic insulating layer 11a has a plurality of inorganic insulating particles 11p bonded to each other, and the inside of the first inorganic insulating layer 11a is densely formed by bonding the particles to each other. A region where the inorganic insulating particles 11p are bonded to each other is referred to as a bonding region 11p1.

  Since the first inorganic insulating layer 11a is made of an inorganic insulating material and has higher rigidity than the resin material, the rigidity of the base body 7 can be increased. Moreover, since the thermal expansion coefficient of the first inorganic insulating layer 11a is lower than the thermal expansion coefficient of the resin material, the thermal expansion coefficient in the planar direction of the wiring board 3 is changed to the thermal expansion coefficient in the planar direction of the electronic component 2. The warpage of the wiring board 3 due to thermal stress can be reduced. In addition, the presence of the first inorganic insulating layer 11a can reduce the thermal expansion coefficient in the thickness direction of the base body 7, and reduce the thermal stress caused by the difference in the thermal expansion coefficient between the base body 7 and the through-hole conductor 8. In addition, disconnection of the through-hole conductor 8 can be reduced. In addition, since the first inorganic insulating layer 11a is made of an inorganic insulating material having a dielectric loss tangent lower than that of the resin material, the first inorganic insulating layer 11a is formed on the uppermost layer and the lowermost layer of the core substrate 5, thereby The signal transmission characteristics of the wiring layer 6 disposed on the upper and lower surfaces can be improved.

  The thickness of the first inorganic insulating layer 11a described above is set to, for example, 3 μm to 100 μm and / or 3% to 10% of the first resin layer 10a, and the Young's modulus is, for example, 10 GPa to 100 GPa, and / Or 10 times or more and 100 times or less of the resin part of the 1st resin layer 10a. The first inorganic insulating layer 11a has a coefficient of thermal expansion in the thickness direction and the plane direction set to, for example, 0 ppm / ° C. or more and 10 ppm / ° C. or less, and a dielectric loss tangent set to, for example, 0.0001 or more and 0.01 or less. .

  The first inorganic insulating layer 11a can be formed of an inorganic insulating material such as silicon oxide, aluminum oxide, boron oxide, magnesium oxide, or calcium oxide, and has a low dielectric loss tangent and a low thermal expansion coefficient. From the viewpoint, it is desirable to use silicon oxide. In particular, the use of amorphous silicon oxide can reduce the occurrence of cracks in the first inorganic insulating layer by reducing the anisotropy of the coefficient of thermal expansion caused by the crystal structure anisotropy.

  The inorganic insulating particles 11p constituting the first inorganic insulating layer 11a are preferably spherical. As a result, by reducing the gap between the inorganic insulating particles 11p, the internal structure of the first inorganic insulating layer 11a can be made dense, so that the rigidity of the first inorganic insulating layer 11a can be improved.

  Moreover, it is desirable that the particle diameter of the inorganic insulating particles 11p is set to 3 nm or more and 110 nm or less. As a result, the bond between the inorganic insulating particles 11p can be strengthened, and the internal structure of the first inorganic insulating layer 11a can be made dense. In addition, the particle size of the inorganic insulating particles 11p is a cross-section enlarged to include 20 to 50 particles by observing the polished surface or fractured surface of the first inorganic insulating layer 11a with a field emission electron microscope. And measuring the maximum diameter of each particle in the enlarged cross section.

  The base body 7 is provided with a through hole T that penetrates the base body 7 in the thickness direction and has a cylindrical shape with a diameter of 0.1 mm to 1 mm, for example. Inside the through hole T, a through hole conductor 8 that electrically connects the upper and lower wiring layers 6 of the core substrate 5 is formed in a cylindrical shape along the inner wall of the through hole T. As this through-hole conductor 8, for example, a conductor formed of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium can be used, and the coefficient of thermal expansion is, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less. Is set.

  An insulator 9 is formed in a columnar shape in the hollow portion of the through-hole conductor 8 formed in a cylindrical shape, and is supported by a via conductor 14 described later. The insulator 9 can be formed of a resin material such as polyimide resin, acrylic resin, epoxy resin, cyanate resin, fluorine resin, silicon resin, polyphenylene ether resin, or bismaleimide triazine resin.

  On the other hand, a pair of wiring layers 6 are formed on the upper and lower surfaces of the core substrate 5 as described above. The wiring layer 6 includes a second resin layer 10b, a second inorganic insulating layer 11b, a conductive layer 13, a via hole V, and a via conductor 14. The conductive layer 13 and the via conductor 14 are electrically connected to each other and have a function as a ground wiring, a power supply wiring, and / or a signal wiring.

  The second resin layer 10b functions as an insulating member that suppresses a short circuit between the conductive layers 13. The second resin layer 10b can be formed of 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.

  The second resin layer 10b has a thickness set to, for example, 3 μm to 30 μm, and a Young's modulus set to, for example, 0.2 GPa to 20 GPa. In addition, the second resin layer 10b has a dielectric loss tangent set to, for example, 3 or more and 4 or less, and a coefficient of thermal expansion in a plane direction or a thickness direction is set to, for example, 20 ppm / ° C. or more and 50 ppm / ° C. or less.

The second resin layer 10b desirably contains a second inorganic insulating filler 12b. The second inorganic insulating filler 12b can be formed of the same material as the first inorganic insulating filler 12a, and reduces the coefficient of thermal expansion of the second resin layer 10b and increases the rigidity of the second resin layer 10b. Can do.

  The second inorganic insulating layer 11b is formed on the second resin layer 10b, and similarly to the first inorganic insulating layer 11a described above, the inorganic insulating material has higher rigidity and lower thermal expansion coefficient and dielectric loss tangent than the resin material. Therefore, the same effect as that of the first inorganic insulating layer 11a is obtained.

  The thickness of the second inorganic insulating layer 11b is set to, for example, 3 μm or more and 30 μm or less and / or 0.5 to 10 times the thickness of the second resin layer 10b. Other configurations are the same as those of the first inorganic insulating layer 11a, for example.

  The conductive layer 13 is formed on the second inorganic insulating layer 11b and is separated from each other in the thickness direction via the second resin layer 10b and the second inorganic insulating layer 11b. The conductive layer 13 can be formed of a metal material such as copper, silver, gold, aluminum, nickel, or chromium, for example. The conductive layer 13 is set to have a thickness of, for example, 3 μm or more and 20 μm or less, and a thermal expansion coefficient of, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less.

  The via conductor 14 connects the conductive layers 13 that are spaced apart from each other in the thickness direction, and is formed in a columnar shape that becomes narrower toward the core substrate 5. As the via conductor 14, for example, a conductor formed of a conductive material such as copper, silver, gold, aluminum, nickel, or chromium can be used, and the coefficient of thermal expansion is set to, for example, 14 ppm / ° C. or more and 18 ppm / ° C. or less. Yes.

  On the other hand, as shown in FIG. 2A, in the wiring substrate 3 of the present embodiment, the first inorganic insulating layer 11a has a groove portion D penetrating in the thickness direction, and the groove portion D includes one of the first resin layers 10a. Part (first filling part 10a1) is filled. Therefore, when stress is applied to the wiring board 3, the first filling portion 10 a 1 having a low Young's modulus relieves the stress applied to the first inorganic insulating layer 11 a in the groove portion D. The generation of cracks in the layer 11a can be reduced. As a result, the wiring board 3 having excellent electrical reliability can be obtained.

  The first resin layer 10a is in contact with the lower surface of the first inorganic insulating layer 11a, and the first filling portion 10a1 is disposed in the groove portion D. Therefore, due to the anchor effect, the adhesive strength between the first resin layer 10a and the first inorganic insulating layer 11a can be increased, and the peeling between the first resin layer 10a and the first inorganic insulating layer 11a can be reduced.

  As shown in FIG. 2B, in the present embodiment, the groove portion D is formed in a mesh shape in a plan view and includes a plurality of small grooves D1. Since the plurality of small grooves D1 are arranged along at least two different directions in plan view, when stress is applied to the wiring board 3, the applied stress is dispersed in different directions, and stress concentration is reduced. be able to.

  Moreover, as shown in FIG. 2B, it is desirable that the end portions of the plurality of small grooves D1 are connected to other small grooves D1 so as not to be open ends. For example, in FIG. 2B, the end of the first small groove D1a is connected to the end of the second small groove D1b at the intersection C, and both ends are not open ends. With such a configuration, compared to the case where the end of the small groove D1 is an open end, that is, the state where it is not connected to any of the small grooves D1, the stress applied to the end of the small groove D1 is easily dispersed, and cracks are generated. It is because it can reduce.

Moreover, since the groove part D of this embodiment has the some small groove D1 along a different direction, compared with the case where the groove part D consists of a single linear small groove, the linear area | region of the groove part D Since the stress applied between the inner wall of the groove D and the first filling portion 10a1 along the longitudinal direction of the linear region can be reduced, the inner wall of the groove D and the first filling portion 10a1 can be reduced. Can be reduced. The individual small grooves D1 may have any shape, for example, in plan view.

  Further, the groove portion D has an annular portion formed in an annular shape (for example, a closed shape such as a circular shape or a polygonal shape) in plan view, and the first inorganic insulating layer 11a is surrounded by the annular portion of the groove portion D. It is desirable to have the first inorganic insulating portion 11a1. As a result, since each first inorganic insulating portion 11a1 is surrounded by the first filling portion 10a1 having a low Young's modulus, the stress applied to each first inorganic insulating portion 11a1 can be relaxed, and as a result, the first inorganic insulating layer The crack of 11a can be reduced.

  As described above, since the first resin layer 10a has the first resin portion 10a1 filled in the groove portion D, the first resin layer 10a adheres well to the inner wall of the groove portion D, and as a result, the first filling portion 10a1 becomes the groove portion. Peeling from the inner wall of D is reduced. Moreover, when the groove part D is located directly under the conductive layer 13, it is desirable that the first filling part 10a1 is in close contact with the conductive layer 13 at the upper end of the groove part D. In this case, compared with the case where the first filling portion 10a1 does not reach the upper end of the groove portion D and a cavity is formed between the first filling portion 10a1 and the conductive layer 13, the conductive layers 13 separated from each other in the thickness direction. Insulating property between the conductive layers 13 can be increased, and short circuit between the conductive layers 13 can be reduced. Moreover, the adhesive strength between the first inorganic insulating layer 11a and the conductive layer 13 can be increased. Moreover, when the groove part D is not located directly under the conductive layer 13, that is, when the groove part D is located outside the region directly under the conductive layer 13 on the first inorganic insulating layer 11a, the first filling part 10a1 In this case, it is desirable that the second resin layer 10b formed on the first inorganic insulating layer 11a is in close contact. The adhesive strength between the first inorganic insulating layer 11a and the second resin layer 10b located on the upper surface (main surface on which the conductive layer 13 is formed) can be increased.

  The ratio of the volume of the first filling part 10a1 in the first inorganic insulating layer 11a, that is, the ratio of the volume of the first filling part 10a1 to the total volume of the first inorganic insulating part 11a1 and the first filling part 10a1 is 1%. It is desirable to set it to 15% or less. Moreover, it is desirable that the volume ratio of the first inorganic insulating portion 11a1 in the first inorganic insulating layer 11a is set to 85% or more and 99% or less. In this case, it is possible to increase the rigidity of the first inorganic insulating layer 11a and reduce the coefficient of thermal expansion and the dielectric loss tangent. The volume ratio of the first filling portion 10a1 in the first inorganic insulating layer 11a is determined by polishing the main surface of the first inorganic insulating layer 11a and taking an electron micrograph as shown in FIG. It is measured by obtaining the area of one inorganic insulating part 11a1 and the first filling part 10a1, considering the area as a volume, and obtaining the ratio thereof.

  Further, the first filling portion 10a1 desirably includes the first inorganic insulating filler 12a in the groove portion D. As a result, the coefficient of thermal expansion of the first filling portion 10a1 can be brought close to that of the first inorganic insulating layer 11a, so that the stress applied to the first inorganic insulating layer 11a when the heat is applied to the wiring board 3 is relieved. can do. Further, since the coefficient of thermal expansion of the first filling part 10a1 can be brought close to the first inorganic insulating layer 11a, when heat is applied to the wiring board 3, the second filling part 10b1 and the first inorganic insulating layer 11a Peeling can be reduced. Further, even if a crack is generated in the first filling portion 10a1 due to the stress applied to the first filling portion 10a1, the extension of the crack in the first filling portion 10a1 is made of a material harder than the resin material. It can be suppressed by the insulating filler 12a. Note that a plurality of the first inorganic insulating fillers 12a are desirably included along the width direction of the groove D.

  The first inorganic insulating filler 12a is preferably made of the same inorganic insulating material as the first inorganic insulating layer 11a. As a result, the thermal expansion coefficient of the first filling portion 10a1 can be made closer to the first inorganic insulating layer 11a.

  The width of the groove part D orthogonal to the longitudinal direction is set to, for example, 0.3 μm or more and 5 μm or less. By setting the width of the groove D to be 0.3 μm or more, the first inorganic insulating filler 12a can be easily disposed in the groove D. Moreover, the ratio of the 1st inorganic insulating part 11a1 with respect to the sum total of the 1st inorganic insulating part 11a1 and the 1st filling part 10a1 can be raised because the width | variety of the groove part D shall be 5 micrometers or less, and the 1st inorganic insulating layer 11a is increased. The coefficient of thermal expansion and the dielectric loss tangent can be reduced.

  The width of the groove D is from the lower surface (main surface adjacent to the first resin layer) side of the first inorganic insulating layer 11a to the upper surface (main surface adjacent to the conductive layer 13) side of the first inorganic insulating layer 11a. It is desirable to be smaller. As a result, the amount of the first filling portion 10a1 can be reduced from the lower surface side of the first inorganic insulating layer 11a toward the upper surface side of the first inorganic insulating layer 11a, and the coefficient of thermal expansion can be reduced. The difference in coefficient of thermal expansion among the first resin layer 10a, the first inorganic insulating layer 11a, and the conductive layer 13 can be reduced. Further, when the groove D is formed immediately below the conductive layer 13, increasing the contact area between the conductive layer 13 and the first inorganic insulating layer 11a increases the insulation on the upper surface side of the first inorganic insulating layer 11a. In addition, the signal transmission characteristics of the conductive layer 13 can be enhanced. The width of the upper end of the groove D is preferably set to be 0.5 times or more and 0.97 times or less of the lower end of the groove D.

  On the other hand, as shown in FIG. 3, in the wiring board 3 of the present embodiment, the second inorganic insulating layer 11b has a groove portion D penetrating in the thickness direction, like the first inorganic insulating layer 11a described above. The groove portion D is filled with a part of the second resin layer 10b (second filling portion 10b1). Therefore, when stress is applied to the wiring substrate 3, the second filling portion 10 b 1 having a low Young's modulus relieves the stress applied to the second inorganic insulating layer 11 b in the groove portion D. Generation of cracks in the layer 11b can be reduced. As a result, the wiring board 3 having excellent electrical reliability can be obtained.

  The second inorganic insulating layer 11b, the second resin layer 10b, the second filling portion 10b1, and the second inorganic insulating filler 12b are the first inorganic insulating layer 11a, the first resin layer 10a, the first filling portion 10a1, and the first filling portion described above. It is desirable to have the same configuration as the inorganic insulating filler 12a.

  As shown in FIG. 3, it is desirable that the groove D is filled with a part of the conductive layer 13 on the upper surface of the second inorganic insulating layer 11b. As a result, the adhesive strength between the second inorganic insulating layer 11b and the conductive layer 13 can be increased by the anchor effect. Therefore, even if the conductive layer 13 is further miniaturized, the conductive layer 13 and the second inorganic insulating layer 11b can be firmly bonded. Note that a part of the conductive layer 13 is desirably bonded to the second filling portion 10b1 in the groove portion D.

  Thus, the mounting structure 1 described above exhibits a desired function by driving or controlling an electronic component based on a power supply or a signal supplied via the wiring board 3.

  Next, the manufacturing method of the mounting structure 1 mentioned above is demonstrated based on FIGS.

(Production of core substrate)
(1) As shown in FIGS. 4A and 4B, a first inorganic insulating sol 11ax containing a solid content made of a plurality of inorganic insulating particles 11p and a first solvent, and copper as a support member for the first inorganic insulating sol 11ax The foil 13x is prepared, and the first inorganic insulating sol 11ax is applied to one main surface of the copper foil 13x.

The first inorganic insulating sol 11ax preferably contains 1% to 50% of the inorganic insulating particles 11p, and preferably contains 50% to 99% of the first solvent. As a result, by containing 1% or more of the inorganic insulating particles 11p, the internal structure of the first inorganic insulating layer 11a can be made dense and thick. Further, by containing 50% or more of the first solvent, the first inorganic insulating sol 11ax
Thus, the flatness of the upper surface of the wiring substrate 3 can be improved by improving the flatness of the upper surface of the first inorganic insulating layer 11a.

  Here, the particle size of the inorganic insulating particles 11p is preferably set to 3 nm or more. In this case, the viscosity of the first inorganic insulating sol 11ax can be reduced.

  As the first solvent, for example, a solvent containing an organic solvent such as methanol, isopropanol, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether or dimethylacetamide can be used. Among these, it is desirable to use a solvent containing methanol or propylene glycol monomethyl ether. As a result, the first inorganic insulating sol 11ax can be uniformly applied, and the first solvent can be efficiently evaporated in the step (2).

  The application of the first inorganic insulating sol 11ax can be performed using, for example, a dispenser or screen printing.

  The first inorganic insulating sol 11ax applied to one main surface of the copper foil 13x is formed in a flat plate shape, and the thickness after drying is set to, for example, 3 μm or more and 110 μm or less.

  (2) As shown in FIG. 5A, the first solvent is evaporated, the solid content remaining by the evaporation is heated and the inorganic insulating particles 11p are bonded to each other, whereby the first inorganic insulating sol 11ax is bonded to the first inorganic insulating sol 11ax. A first laminated sheet 16a having a copper foil 13x and a first inorganic insulating layer 11a is formed as the layer 11a.

  Here, since the first inorganic insulating sol 11ax is formed in a flat plate shape on one main surface of the copper foil 13x, when the first solvent evaporates, the solid content of the first inorganic insulating sol 11ax is in the plane direction. Therefore, as shown in FIG. 5B, a groove D that penetrates the first inorganic insulating layer 11a in the thickness direction can be formed.

  Further, it is desirable that the copper foil 13x has a convex portion formed on one main surface to which the first inorganic insulating sol 11ax is applied in the step (1), for example, by etching or plasma treatment. As a result, when the solid content of the first inorganic insulating sol 11ax contracts in the plane direction by reducing the volume of the first inorganic insulating sol 11ax on the convex portion of the copper foil 13x, the volume of the first inorganic insulating sol 11ax on the convex portion of the copper foil 13x is reduced. Thus, the shrinkage is suppressed, and the groove portion D can be formed in the non-formation region portion of the convex portion. Therefore, the size, density, and formation region of the groove D can be adjusted by adjusting the size, density, and formation region of the protrusions on one main surface of the copper foil 13x.

  Moreover, since a part of groove part D is formed along a convex part, the shape of the groove part D can be adjusted easily by adjusting the shape of a convex part. For example, it is easy to form a plurality of first inorganic insulating portions 11a1 surrounded by the groove portion D by forming the convex portion in a circular shape in a plan view, thereby forming the groove portion D in a circular shape in a plan view. It becomes.

  Further, when evaporating the first solvent, it is desirable to cause the inorganic insulating particles 11p to settle to the copper foil 13x side by gravity. As a result, the density of the inorganic insulating particles 11p on the copper foil 13x side of the solid content of the first inorganic insulating sol 11ax can be increased, and when the first inorganic insulating sol 11ax is heated, the solidity of the first inorganic insulating sol 11ax is increased. Since the amount of shrinkage on the high density copper foil 13x side can be reduced in minutes, the width of the groove D is changed from the lower surface (the other main surface where the copper foil 13x is not formed) side of the first inorganic insulating layer 11a to the upper surface (copper copper). The foil 13x can be formed smaller toward the main surface) side. The inorganic insulating particles 11p can be settled by gravity, for example, by setting the temperature at the time of evaporation low and increasing the evaporation time.

  It is desirable that the heating of the first inorganic insulating sol 11ax is set to a temperature not lower than the boiling point of the first solvent and lower than the crystallization start temperature of the inorganic insulating particles 11p. Specifically, for the heating of the first inorganic insulating sol 11ax, the temperature is set to, for example, 100 degrees to less than 600 degrees and the time is set to, for example, 0.5 hours to 24 hours. As a result, when the heating temperature is equal to or higher than the boiling point of the first solvent, the remaining first solvent can be efficiently evaporated. Further, when the heating temperature is lower than the crystallization start temperature of the inorganic insulating particles 11p, the crystallization of the inorganic insulating particles 11p can be reduced and the ratio of the amorphous state can be increased. As a result, the inorganic insulating particles 11p can reduce the occurrence of cracks by reducing the anisotropy of the thermal expansion coefficient due to the crystal structure anisotropy. In particular, when silicon oxide is used as the inorganic insulating material of the inorganic insulating particles 11p, crystallization of the inorganic insulating particles 11p can be effectively reduced. The crystalline phase region in the inorganic insulating material is preferably set to less than 25% of the volume of the first inorganic insulating layer 11a, and more preferably set to less than 10%. The crystallization start temperature is a temperature at which the amorphous inorganic insulating material starts to crystallize.

  Here, the particle size of the inorganic insulating particles 11p is desirably set to 110 nm or less. As a result, even if the heating temperature of the first inorganic insulating sol 11ax is lower than the crystallization start temperature of the inorganic insulating particles 11p, the inorganic insulating particles 11p can be firmly bonded to each other. This is because the first particle size is set to an extremely small value of 110 nm or less, and the atoms of the inorganic insulating particles 11p, particularly the atoms on the surface, actively move. Therefore, the inorganic insulating particles 11p are strong even at such a low temperature. It is assumed that

  Further, as the particle diameter of the inorganic insulating particles 11p is set smaller, the inorganic insulating particles 11p can be more strongly bonded at a lower temperature. The temperature at which the inorganic insulating particles 11p can be firmly bonded to each other is, for example, about 250 ° C. when the particle size is set to 110 nm or less, and about 150 ° C. when the particle size is set to 50 nm or less. is there.

  The heating of the first inorganic insulating sol can be performed, for example, in an air atmosphere. Moreover, when raising temperature to 150 degreeC or more, in order to suppress the oxidation of the copper foil 13x, it is desirable to heat the 1st inorganic insulating sol in inert atmosphere or nitrogen atmosphere, such as a vacuum and argon.

  (3) As shown to FIG. 6A, the 1st resin precursor sheet | seat 10ax used as a 1st resin layer is prepared. The first resin precursor sheet 10ax can be produced, for example, by laminating a plurality of sheets including an uncured resin and a base material. The uncured state is an A-stage or B-stage according to ISO 472: 1999.

  (4) As shown in FIG. 6B, the first laminated sheet 16 is laminated on the upper and lower surfaces of the first resin precursor sheet 10ax via the first inorganic insulating layer 11a, and the laminated body is heated and pressurized in the vertical direction. Thus, the first resin precursor sheet 10ax is cured to form the first resin layer 10a, and the base body 7 having the first resin layer 10a and the first inorganic insulating layer 11a and having the copper foil 13x disposed on the upper and lower sides is provided. Form. A configuration including the base body 7 and the copper foils 13 x disposed above and below the base body 7 is referred to as a laminated plate 15.

  On the other hand, when the laminated body is heated and pressurized, the first resin precursor sheet 10ax softens and flows, so that a part of the first resin precursor sheet 10ax is in the groove D of the first inorganic insulating layer 11a. As shown in FIG. 6C, the first filling portion 10a1 can be formed in the groove portion D of the first inorganic insulating layer 11a. Moreover, when filling a part of 1st resin precursor sheet | seat 10ax in the groove part D, the 1st inorganic insulating filler 12a can be distribute | arranged in the groove part D. FIG.

  In addition, since the width of the groove D is small from the lower surface side of the first inorganic insulating layer 11a toward the upper surface side of the first inorganic insulating layer 11a, the first portion is formed in the groove portion D of the first inorganic insulating layer 11a. Part of the resin precursor sheet 10ax can be efficiently filled. Further, the first inorganic insulating filler 12a can be efficiently arranged in the groove D.

  It is desirable that the temperature and pressure of the laminated body is set to a temperature not lower than the curing start temperature of the first resin layer 10a and lower than the thermal decomposition temperature. Specifically, the heat and pressure of the laminate is set such that the temperature is set to 170 ° C. or higher and 230 ° C. or lower, the pressure is set to 2 MPa or higher and 3 MPa or lower, and the time is set to 0.5 hours or longer and 2 hours or shorter, for example. Is set. The curing start temperature is a temperature at which the resin becomes a C-stage according to ISO 472: 1999. The thermal decomposition temperature is a temperature at which the mass of the resin is reduced by 5% in thermogravimetry according to ISO11358: 1997.

  As described above, the laminate 15 can be formed. The laminated plate 15 includes a pair of first inorganic insulating layers 11a and a first resin layer 10a disposed between the first inorganic insulating layers 11a. The first inorganic insulating layer 11a is arranged in the thickness direction. There is a groove portion D that penetrates, and a part of the first resin layer 10a is disposed in the groove portion D.

  (5) As shown in FIG. 6D, the through-hole conductor 8 that penetrates the base body 7 in the vertical direction is formed, and the conductive layer 13 is formed on the base body 7. Specifically, this is performed as follows.

  First, a plurality of through holes T penetrating the substrate 7 in the thickness direction are formed by, for example, drilling or laser processing. Next, a cylindrical through-hole conductor 8 is formed by depositing a conductive material on the inner wall of the through-hole T by, for example, electroless plating, vapor deposition, CVD or sputtering. Next, the inside of the cylindrical through-hole conductor 8 is filled with a resin material or the like to form an insulator 9. Next, a conductive material is deposited on the exposed portion of the insulator 9 by, for example, electroless plating, vapor deposition, CVD, sputtering, or the like. Next, the conductive layer 13 is formed by patterning the copper foil 13x using a photolithography technique, etching, or the like.

  The core substrate 5 can be manufactured as described above.

(Production of wiring board)
(6) As shown in FIGS. 7A and 7B, similarly to the steps (1) and (2), the second laminated sheet 16b having the copper foil 13x and the second inorganic insulating layer 11b is formed. As shown in FIG. 2, the uncured second resin precursor sheet 10bx is placed on the second laminated sheet 16b via the second inorganic insulating layer 11b.

  (7) As shown in FIG. 8A, the second resin precursor sheet 10bx and the second laminated sheet 16b are laminated on the upper and lower surfaces of the core substrate 5 via the second resin precursor sheet 10bx, and the laminated body is moved up and down. By heating and pressing in the direction, the second resin precursor sheet 10bx is cured to form the second resin layer 10b.

  On the other hand, when the laminated body is heated and pressurized, the second resin precursor sheet 10bx softens and flows in the same manner as in the step (4), so that the second resin precursor sheet 10bx flows into the groove D of the second inorganic insulating layer 11b. Since part of the two resin precursor sheets 10bx can be filled, the second filling portion 10bx can be formed in the groove portion D of the second inorganic insulating layer 11b as shown in FIG. 8B. Further, when the groove portion D is partially filled with the second resin precursor 10bx, the second inorganic insulating filler 12b can be disposed in the groove portion D.

  Moreover, the heating and pressurization of this laminated body can be performed similarly to the process of (4), for example.

  (8) As shown in FIG. 9A, for example, by etching using a mixed solution of sulfuric acid and hydrogen peroxide solution, ferric chloride solution or cupric chloride solution, the copper foil 13x from the second inorganic insulating layer 11b. To peel off.

  (9) As shown in FIG. 9B, the via conductors 14 that penetrate the second resin layer 10b and the second inorganic insulating layer 11b in the vertical direction are formed, and the conductive layer 13 is formed on the second inorganic insulating layer 11b. Specifically, this is performed as follows.

  First, via holes V are formed in the second resin layer 10b and the second inorganic insulating layer 11b by, for example, a YAG laser device or a carbon dioxide gas laser device, and at least a part of the conductive layer 15 is exposed in the via holes V. Next, the via conductor 14 is formed in the via hole V and the conductive layer 13 is formed on the second inorganic insulating layer 11b by, for example, a semi-additive method, a subtractive method, or a full additive method.

  Here, it is desirable to perform a desmear process after forming the via hole V, and to etch the upper end part of the second filling part 10b1 by the desmear process. As a result, a depression can be formed at the upper end of the groove D, and a part of the conductive layer 13 can be disposed in the groove D by forming the conductive layer 13 on the second inorganic insulating layer 11b having the depression. .

  (10) As shown in FIG. 9C, the wiring layers 6 are formed on the upper and lower surfaces of the core substrate 5 by repeating the steps (6) to (9). Note that the wiring layer 6 can be made more multilayered by repeating this step.

  The wiring board 3 can be produced as described above.

(Production of mounting structure)
(11) By mounting the electronic component 2 on the wiring board 3 via the bumps 4 by flip-chip mounting, the mounting structure 1 shown in FIG. 1 can be manufactured.

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

  For example, in the above-described embodiment, the present invention has been described by taking a build-up multilayer substrate including a core substrate and a wiring layer as an example, but the present invention can also be applied to a wiring substrate other than the build-up multilayer substrate. For example, the present invention can also be applied to a single-layer substrate made of only an interposer substrate, a coreless substrate, or a core substrate.

  In the embodiment of the present invention described above, the first resin layer includes the base material. However, the first resin layer may not include the base material or may include the metal plate. .

  In the embodiment of the present invention described above, the first resin layer and the second resin layer are formed of a thermosetting resin. However, at least one of the first resin layer and the second resin layer or both of them are heated. It may be formed of a plastic resin. As this thermoplastic resin, for example, a fluorine resin, an aromatic liquid crystal polyester resin, a polyether ketone resin, a polyphenylene ether resin, a polyimide resin, or the like can be used.

In the embodiment of the present invention described above, both the core substrate and the wiring layer are provided with the inorganic insulating layer in the wiring substrate, but the wiring substrate is provided with at least one of the core substrate and the wiring layer having the inorganic insulating layer. It only has to be prepared.

  In the above-described embodiment of the present invention, the base body includes the first resin layer and the inorganic insulating layers arranged above and below the first resin layer. For example, a resin substrate or a ceramic substrate may be used.

  In the above-described embodiment of the present invention, the configuration in which the inorganic insulating layer and the conductive layer are in contact with each other has been described as an example. However, as illustrated in FIG. 10A, between the inorganic insulating layer 11A and the conductive layer 13A. The third resin layer 10cA may be interposed. As for this 3rd resin layer 10cA, it is desirable that thickness is set smaller than 1st resin layer 10aA and 2nd resin layer 10bA.

  In the embodiment of the present invention described above, the plurality of small grooves D1 are connected to each other, but the small grooves D1 may be separated from each other.

  In the embodiment of the present invention described above, the first inorganic insulating sol is heated after evaporating the first solvent in the step (2). However, the evaporation of the first solvent and the first inorganic insulating sol Heating may be performed simultaneously.

  Moreover, in embodiment of this invention mentioned above, although the uncured 2nd resin precursor sheet | seat was mounted on the 2nd inorganic insulating layer at the process of (6), it is an uncured and liquid 2nd resin precursor. The body sheet may be applied to the second inorganic insulating layer 11 and the groove portion may be filled with the second resin precursor sheet.

  In the above-described embodiment of the present invention, the laminate comprising the core substrate, the second resin precursor sheet, and the second laminate sheet is heated and pressed in the step (7) to provide the second resin layer in the groove. The second filling portion was formed by filling a part of the resin, and after the step (6), before forming the laminate, the second resin precursor sheet and the second laminate sheet were heated and pressurized, You may form a 2nd filling part in a groove part.

  In the embodiment of the present invention described above, after peeling the copper foil from the second inorganic insulating layer in the step (8), a conductive layer is formed on the second inorganic insulating layer in the step (9). However, the conductive layer may be formed by patterning the copper foil without peeling the copper foil from the second inorganic insulating layer.

  Further, in the above-described embodiment of the present invention, the laminated board provided with the copper foil is used. However, the laminated board may include a metal foil made of a material other than copper, or a conductive material layer other than the metal foil. Or a conductive material layer and only a substrate.

  Moreover, in embodiment of this invention mentioned above, although the laminated sheet provided with copper foil was used as a supporting member, the laminated sheet should just be equipped with supporting members other than copper foil, for example, copper is used as a supporting member. A metal foil other than the foil may be used, or a conductive material layer other than the metal foil may be used. Moreover, you may use insulating material layers, such as a resin sheet which consists of thermoplastic resins, as a supporting member.

Examples
Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

(Evaluation method)
A laminated board comprising a copper foil, an inorganic insulating layer made of inorganic insulating particles, and a resin layer containing an inorganic insulating filler is produced, and a cross section obtained by cutting the laminated board in the thickness direction and polishing it is subjected to field emission. A photograph was taken and observed using a scanning electron microscope (JSM-7000F, manufactured by JEOL).

(Conditions for making laminates)
First, “PGM-ST” (average particle diameter 10-15 nm) manufactured by Nissan Chemical Industries, Ltd. was prepared as an inorganic insulating sol containing inorganic insulating particles made of silicon oxide.

  Next, an inorganic insulating sol was applied onto the copper foil, and the laminated sheet was prepared by heating the inorganic insulating sol and evaporating the solvent under the conditions of temperature: 150 ° C., time: 2 hours, atmosphere: air. .

  Next, a laminated sheet is laminated on each of the upper and lower surfaces of a resin precursor sheet containing an uncured cyanate-based resin and an inorganic insulating filler made of silicon oxide, and the conditions are: time: 1 hour, pressure: 3 MPa, temperature: 180 ° C. Below, the laminated body was produced by heating and pressurizing the laminated body.

(Example)
As shown in FIG. 10B, the laminated plate manufactured as described above includes a copper foil 13xB, an inorganic insulating layer 11B, and a resin layer 10B, and the inorganic insulating layer 11B has a groove portion DB penetrating in the thickness direction. The groove DB was filled with a part of the resin layer 10B. In addition, in the inorganic insulating layer 11B of the laminate, it was observed that the inorganic insulating particles 11pB were bonded to each other as shown in FIGS. 11A and 11B.

DESCRIPTION OF SYMBOLS 1 Mounting structure 2 Electronic component 3 Wiring board 4 Bump 5 Core board 6 Wiring layer 7 Base body 8 Through-hole conductor 9 Insulator 10a 1st resin layer 10b 2nd resin layer 11a 1st inorganic insulating layer 11b 2nd inorganic insulating layer 11p Inorganic insulating particles 11p1 Bonding region 12a First inorganic insulating filler 12b Second inorganic insulating filler 13 Conductive layer 13x Copper foil 14 Via conductor 15 Laminated plate 16a First laminated sheet 16b Second laminated sheet T Through hole V Via hole D Groove C Intersection

Claims (9)

A support member and an inorganic insulating layer disposed on the support member and having a groove penetrating in the thickness direction ;
The inorganic insulating layer has a plurality of inorganic insulating particles bonded to each other, and is a laminated sheet. In the laminated sheet according to claim 1,
A resin layer disposed on the inorganic insulating layer;
The said resin layer has a part arrange | positioned in the said groove | channel of the said inorganic insulating layer, The laminated sheet characterized by the above-mentioned. In the laminated sheet according to claim 1,
An inner wall of the groove is formed of the plurality of inorganic insulating particles. In the laminated sheet according to claim 1,
The laminated sheet is characterized in that the groove is open to the support member side. In the laminated sheet according to claim 4,
A convex portion is formed on one main surface of the support member on the side where the inorganic insulating layer is located,
The laminated sheet is characterized in that the groove is formed along the convex portion. In the laminated sheet according to claim 1,
The laminated sheet, wherein the support member is a copper foil. In the laminated sheet according to claim 3,
The laminated sheet, wherein the plurality of inorganic insulating particles are spherical. A pair of inorganic insulating layers having a groove penetrating in the thickness direction, and a resin layer disposed between the inorganic insulating layers,
The inorganic insulating layer has a plurality of inorganic insulating particles bonded to each other . A resin layer and an inorganic insulating layer disposed on the resin layer and having a groove penetrating in the thickness direction ;
The wiring board according to claim 1, wherein the inorganic insulating layer has a plurality of inorganic insulating particles bonded to each other .