laminate

Abstract

To provide a laminate that has a low dielectric property and that can be used for high-density wiring.SOLUTION: A laminate comprises at least one glass plate layer and at least one resin layer, and has: a dielectric constant of 5 or less for the glass plate at 25°C and a frequency of 2.45 GHz; and a dielectric loss tangent of 0.003 or less for the glass plate at 25°C and a frequency of 2.45 GHz.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a laminate, and more specifically, to a laminate suitable for a multilayer wiring board compatible with high-frequency communication.

Background Art

[0002] Currently, development is underway to support the fifth-generation mobile communication system (5G), and technical studies are being conducted to increase the speed, transmission capacity, and reduce latency of the system. For multilayer wiring boards used in this application, it is also required to reduce transmission loss in high-frequency communication.

Disclosure of the Invention

Problems to be Solved by the Invention

[0003] In recent years, with the increasing functionality of electronic devices, the wiring of multilayer wiring boards has become finer. To cope with this, multilayer wiring boards require a core layer with good surface flatness and excellent dimensional stability. However, in the current resin layer impregnated with glass cloth, the surface smoothness and dimensional stability are insufficient.

[0004] The present invention has been made in view of the above circumstances, and its technical problem is to provide a laminate having low dielectric characteristics and suitable for high-density wiring.

Means for Solving the Problems

[0005] As a result of repeating various experiments, the inventors have found that the above technical problems can be solved by laminating a glass plate having low dielectric characteristics and a resin layer, and propose it as the present invention. That is, the laminate of the present invention includes at least one or more glass plates and at least one or more resin layers, and the relative permittivity of the glass plate at 25°C and a frequency of 2.45 GHz is 5 or less, and the loss tangent of the glass plate at 25°C and a frequency of 2.45 GHz is 0.003 or less. Thereby, transmission loss can be reduced when an electrical signal is transmitted to a high-frequency device. Here, the "relative permittivity at 25°C and a frequency of 2.45 GHz" can be measured, for example, by a well-known cavity resonator method. The "loss tangent at 25°C and a frequency of 2.45 GHz" can be measured, for example, by a well-known cavity resonator method.

[0006] The laminate of the present invention includes at least one or more glass plates. The glass plate is suitable as a core layer of a multilayer wiring board, and when a glass plate is provided, the following effects can be obtained. Since the thermal expansion coefficient of the glass plate is lower than that of the resin, the difference in thermal expansion coefficient between the glass plate and silicon, which is the material of the semiconductor chip, can be reduced. Thereby, the stress on the connection part during chip mounting is reduced, and the connection reliability can be improved. In addition, since the glass plate has higher flatness than the resin, it is advantageous for forming fine wiring. Furthermore, the glass plate has less expansion and contraction due to heat and moisture absorption than the resin and has excellent dimensional stability. Thereby, the pattern misalignment during photolithography and via formation is reduced, which is advantageous for forming fine wiring.

[0007] The laminate of the present invention includes at least one or more glass plates and at least one or more resin layers. Thereby, by using the glass plate as a core layer and further laminating the resin layer, high-density wiring of a multilayer wiring board becomes possible.

[0008] In the laminate of the present invention, the relative permittivity of the glass plate at 25°C and a frequency of 2.45 GHz is 5 or less, and the loss tangent of the glass plate at 25°C and a frequency of 2.45 GHz is 0.003 or less. Thereby, transmission loss can be reduced in high-frequency communication.

[0009] In addition, in the laminate of the present invention, it is preferable that the resin layer is a prepreg obtained by impregnating a glass cloth with a resin.

[0010] In addition, in the laminate of the present invention, it is preferable that a metal layer is formed on the surface and / or inside of the glass plate.

[0011] In addition, in the laminate of the present invention, it is preferable that the metal layer contains any one or more of copper, silver, gold, aluminum, molybdenum, tungsten, nickel, tin, and alloys thereof.

[0012] In addition, in the laminate of the present invention, it is preferable that the thickness of the glass plate is 5 to 50 μm. In order to reduce the dielectric loss of the laminate, it is necessary to lower the relative permittivity and dielectric tangent of the laminate. Further, the propagation speed of the electrical signal is calculated by V = C / √ε, but the relative permittivity changes depending on the signal line width of the laminate, the thickness of the insulator, etc. Therefore, when the thickness of the glass plate is reduced, the distance between the ground and the signal line becomes smaller, and the effective relative permittivity can be lowered. As a result, the propagation speed of the electrical signal can be increased. Furthermore, it becomes easier to form through holes in the glass plate, enabling high-density wiring of the multilayer wiring board.

[0013] In addition, in the laminate of the present invention, it is preferable that the glass plate contains, as a glass composition, in mol%, 60 to 90% of SiO2, 1 to 15% of Al2O3, 5 to 30% of B2O3, 0 to 8% of MgO + CaO + SrO + BaO, 0 to 8% of MgO, and 0 to 8% of CaO. "MgO + CaO + SrO + BaO" refers to the total amount of MgO, CaO, SrO, and BaO.

[0014] In addition, in the laminate of the present invention, it is preferable that through holes are formed in the thickness direction of the glass plate. Thereby, since a wiring structure for establishing conduction between both surfaces of the glass plate can be formed, it becomes easier to apply to high-frequency devices.

[0015] In addition, in the laminate of the present invention, it is preferable that the inner diameter of the through hole formed in the glass plate is 200 μm or less. Thereby, it becomes easy to increase the density of the wiring structure for establishing conduction between both surfaces of the glass plate.

[0016] In addition, in the laminate of the present invention, it is preferable that the difference between the maximum value and the minimum value of the inner diameter of the through hole formed in the glass plate is 100 μm or less. Thereby, it is possible to prevent a situation where the wiring for establishing conduction between both surfaces of the glass plate becomes unduly long, and thus transmission loss can be reduced.

[0017] In addition, in the laminate of the present invention, it is preferable that a metal layer is formed on the inner peripheral surface of the through hole formed in the glass plate.

[0018] In addition, the laminate of the present invention is preferably used for a multilayer wiring board.

Embodiments for Carrying Out the Invention

[0019] The laminate of the present invention includes at least one or more glass plates and at least one or more resin layers. Thereby, with the glass plate serving as the core layer and further laminating the resin layer, high-density wiring of the multilayer wiring board becomes possible. The glass plate is suitable as the core layer of the multilayer wiring board, and when provided with the glass plate, the following effects can be obtained. Since the thermal expansion coefficient of the glass plate is lower than that of the resin, the difference in thermal expansion coefficient between the glass plate and silicon, which is the material of the semiconductor chip, can be reduced. Thereby, the stress on the connection part during chip mounting is reduced, and the connection reliability can be improved. In addition, since the glass plate has higher flatness than the resin, it is advantageous for forming fine wiring. Furthermore, the glass plate has less expansion and contraction due to heat and moisture absorption than the resin and is excellent in dimensional stability. Thereby, the pattern misalignment during photolithography and via formation is reduced, which is advantageous for forming fine wiring.

[0020] The number of glass plates is one or more, preferably two or more, particularly three to twenty layers, and the number of resin layers is one or more, preferably three or more, particularly five to thirty layers. The higher the number of layers, the higher the density of the multilayer wiring board can be achieved.

[0021] In the laminate of the present invention, it is preferable that a metal layer is formed on the surface and / or inside of the glass plate. The metal layer can be used as wiring. Considering the low resistivity, cost, and ease of availability, the metal layer preferably contains any one or more of copper, silver, gold, aluminum, molybdenum, tungsten, nickel, tin, and alloys thereof, and particularly preferably contains copper or an alloy containing copper.

[0022] In the laminate of the present invention, the glass plate preferably contains, in mol%, 60 to 90% of SiO2, 1 to 15% of Al2O3, 5 to 30% of B2O3, 0 to 8% of MgO + CaO + SrO + BaO, 0 to 8% of MgO, and 0 to 8% of CaO as the glass composition. The reasons for limiting the content of each component as described above are shown below. In addition, the following % representation refers to mol% unless otherwise specified.

[0023] A suitable lower limit content of SiO2 is 60%, 61%, 62%, 63%, 64%, 65%, particularly 66%, and a suitable upper limit content is 90%, 85%, 80%, 75%, 73%, 71%, 70%, particularly 69%. If the content of SiO2 is too low, the relative permittivity, dielectric loss tangent, and density tend to increase. Also, the moisture resistance tends to decrease. On the other hand, if the content of SiO2 is too high, the high-temperature viscosity increases, the meltability decreases, and in addition, devitrification crystals such as cristobalite are likely to precipitate during molding.

[0024] Al2O3 is a component that increases the Young's modulus and suppresses phase separation, significantly enhancing the weather resistance. Therefore, a suitable lower limit content of Al2O3 is 1%, 2%, 2.5%, 3%, 3.5%, 4%, particularly 4.5%. On the other hand, if the content of Al2O3 is too high, the liquidus temperature increases, and the devitrification resistance tends to decrease. Therefore, a suitable upper limit content of Al2O3 is 15%, 13%, 12%, 11%, 10%, 9%, 8%, particularly 7%.

[0025] B2O3 is a component that reduces the relative permittivity and dielectric loss tangent, but also reduces the Young's modulus and density. It is also a component that reduces moisture resistance. However, if the content of B2O3 is too low, it becomes difficult to ensure low dielectric properties. In addition, its function as a flux becomes insufficient, resulting in high viscosity at high temperatures and a tendency for the bubble quality to deteriorate. Furthermore, it becomes difficult to achieve low density. Therefore, the preferred lower limit content of B2O3 is 5%, 10%, 15%, 18%, 20%, 21%, 22%, 23%, particularly 24%. On the other hand, if the content of B2O3 is too high, the heat resistance and chemical durability tend to decrease, or the moisture resistance tends to decrease due to phase separation. Therefore, the preferred upper limit content of the B2O3 content is 30%, 29%, 28%, 27%, particularly 26%.

[0026] The content of B2O3 - Al2O3 is preferably 14% or more, 15% or more, 16% or more, 17% or more, 18% or more, 19% or more, 20% or more, 21% or more, 22% or more, 23% or more, particularly 24% or more. If the content of B2O3 - Al2O3 is too low, it becomes difficult to ensure low dielectric properties. Note that "B2O3 - Al2O3" is the content of B2O3 minus the content of Al2O3.

[0027] Alkaline earth metal oxides are components that lower the liquidus temperature and make it difficult to generate devitrified crystals in the glass, and also components that enhance the meltability and formability. If the content of MgO + CaO + SrO + BaO is too low, not only does the devitrification resistance tend to decrease, but also its function as a flux cannot be fully exerted, and the meltability tends to decrease. On the other hand, if the content of MgO + CaO + SrO + BaO is too high, the relative permittivity and dielectric loss tangent increase, the density rises, making it difficult to achieve weight reduction of the glass. In addition, the thermal expansion coefficient becomes unduly high, and the thermal shock resistance tends to decrease. The preferred lower limit content of MgO + CaO + SrO + BaO is 0.1%, 0.5%, 1%, 1.5%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, particularly 3%, and the preferred upper limit content is 6%, 5.5%, 5%, 4.8%, 4.6%, 4.4%, 4.2%, particularly 4%.

[0028] MgO is a component that lowers the high-temperature viscosity and increases the fusibility without reducing the strain point, and among alkaline earth metal oxides, it is the component that is most difficult to increase the density. Also, among alkaline earth metals, it is a component that particularly enhances moisture resistance. However, if the content of MgO is too high, the liquidus temperature rises, and the devitrification resistance tends to decrease. Also, the glass is likely to phase-separate, and the transparency tends to decrease. The preferred lower limit content of MgO is 0%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, particularly 1%, and the preferred upper limit content is 8%, 5%, 4%, 3%, 2.5%, particularly 2%.

[0029] CaO is a component that lowers the high-temperature viscosity and significantly increases the fusibility without reducing the strain point, and in the glass composition system according to the present invention, it is a component that has a great effect of enhancing devitrification resistance. Also, among alkaline earth metals, it is a component that enhances moisture resistance. Therefore, the preferred lower limit content of CaO is 0%, 0.5%, 1%, 1.5%, 2%, particularly 2.5%, and the preferred upper limit content is 8%, 5%, 4.5%, 4%, 3.5%, particularly 3%.

[0030] SrO is a component that lowers the high-temperature viscosity and increases the fusibility without reducing the strain point, but if the content of SrO is too high, the liquid-phase viscosity tends to decrease. Therefore, the SrO content is preferably 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, particularly 0 to 0.1%.

[0031] BaO is a component that lowers the high-temperature viscosity and increases the fusibility without reducing the strain point, but if the content of BaO is too high, the liquid-phase viscosity tends to decrease. Therefore, the content of BaO is preferably 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, 0 to 1.5%, 0 to 1%, 0 to 0.5%, particularly less than 0 to 0.1%.

[0032] In addition to the above components, the following components may also be introduced into the glass composition.

[0033] Alkali metal oxides are components that enhance fusibility and formability. However, if their content is too high, the density will increase, the water resistance will decrease, the thermal expansion coefficient will become unduly high, the thermal shock resistance will decrease, and it will be difficult to match the thermal expansion coefficient of surrounding materials. Therefore, the total content of Li2O, Na2O, and K2O is 0 to 3%, preferably 0 to 2%, 0 to 1%, 0 to 0.5%, 0 to 0.2%, 0 to 0.1%, especially less than 0.001 to 0.05%. The content of each of Li2O, Na2O, and K2O is preferably 0 to 3%, 0 to 2%, 0 to 1%, 0 to 0.5%, 0 to 0.2%, 0 to 0.1%, especially less than 0.001 to 0.01%.

[0034] ZnO is a component that enhances fusibility. However, if it is contained in a large amount in the glass composition, the glass is likely to devitrify and the density is also likely to increase. Therefore, the content of ZnO is preferably 0 to 5%, 0 to 3%, 0 to 0.5%, 0 to 0.3%, especially 0 to 0.1%.

[0035] ZrO2 is a component that increases the Young's modulus. The content of ZrO2 is preferably 0 to 5%, 0 to 3%, 0 to 0.5%, 0 to 0.2%, 0 to 0.16%, 0 to 0.1%, especially 0 to 0.02%. If the content of ZrO2 is too high, the liquidus temperature will increase and devitrified crystals of zircon are likely to precipitate.

[0036] TiO2 is a component that lowers the high-temperature viscosity and enhances fusibility, and is also a component that suppresses solarization. However, if it is contained in a large amount in the glass composition, the glass will be colored and the transmittance is likely to decrease. Therefore, the content of TiO2 is preferably 0 to 5%, 0 to 3%, 0 to 1%, 0 to 0.1%, especially 0 to 0.02%.

[0037] P2O5 is a component that enhances devitrification resistance. However, if it is contained in a large amount in the glass composition, the glass is likely to phase-separate and become milky white, and there is also a risk that the water resistance will decrease significantly. Therefore, the content of P2O5 is preferably 0 to 5%, 0 to 1%, 0 to 0.5%, especially 0 to 0.1%.

[0038] Fe2O3 can be introduced as an impurity component or a fining agent component. However, if the content of Fe2O3 is too high, there is a risk of a decrease in the ultraviolet transmittance. Therefore, the content of Fe2O3 is preferably 0.05% or less, 0.03% or less, particularly 0.02% or less. Here, "Fe2O3" as used in the present invention includes divalent iron oxide and trivalent iron oxide, and the divalent iron oxide shall be handled as being converted to Fe2O3. Note that for other oxides as well, they shall be handled in the same manner based on the oxide notations.

[0039] SnO2 is a component having a good fining action in the high-temperature range and is also a component that reduces the high-temperature viscosity. The content of SnO2 is preferably 0 to 1%, 0.01 to 0.5%, particularly 0.05 to 0.2%. If the content of SnO2 is too high, devitrification crystals of SnO2 are likely to precipitate in the glass.

[0040] Although the addition of SnO2 is suitable as a fining agent, as long as the glass properties are not impaired, CeO2, SO3, C, and metal powders (such as Al, Si, etc.) may be added up to 1% as fining agents.

[0041] As2O3, Sb2O3, F, and Cl also act effectively as fining agents. In the present invention, the inclusion of these components is not excluded, but from an environmental perspective, the content of each of these components is preferably less than 0.1%, particularly less than 0.05%.

[0042] The glass plate according to the present invention preferably has the following characteristics.

[0043] The relative permittivity at 25°C and a frequency of 28 GHz is preferably 5 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, particularly 4.5 or less. If the relative permittivity at 25°C and a frequency of 28 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device is likely to increase.

[0044] The dielectric tangent at 25°C and a frequency of 28 GHz is preferably 0.01 or less, 0.009 or less, 0.008 or less, 0.007 or less, 0.006 or less, 0.005 or less, 0.004 or less, and particularly 0.003 or less. If the dielectric tangent at 25°C and a frequency of 28 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0045] The relative dielectric constant at 25°C and a frequency of 2.45 GHz is preferably 5 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, and particularly 4.5 or less. If the relative dielectric constant at 25°C and a frequency of 2.45 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0046] The dielectric tangent at 25°C and a frequency of 2.45 GHz is preferably 0.003 or less, 0.002 or less, 0.001 or less, 0.0009 or less, 0.0008 or less, and particularly 0.0007 or less. If the dielectric tangent at 25°C and a frequency of 2.45 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0047] The coefficient of thermal expansion in the temperature range of 30 to 380°C is preferably 20×10 -7 ~50×10 -7 / °C, 22×10 -7 ~48×10 -7 / °C, 23×10 -7 ~47×10 -7 / °C, 25×10 -7 ~46×10 -7 / °C, 28×10 -7 ~45×10 -7 / °C, 30×10 -7 ~43×10 -7 / °C, 32×10 -7 ~41×10 -7 / °C, and particularly 35×10 -7 ~39×10 -7It is in °C. When the coefficient of thermal expansion in the temperature range of 30 to 380 °C is outside the above range, the thermal expansion difference from silicon, which is the material of the semiconductor chip, becomes large. Therefore, the stress on the connection part during chip mounting increases, and the connection reliability tends to decrease.

[0048] The strain point is preferably 530 °C or higher, 540 °C or higher, 550 °C or higher, 560 °C or higher, 570 °C or higher, 580 °C or higher, particularly 590 °C or higher. If the strain point is too low, the glass plate tends to thermally contract during the heat treatment process in the production of the multilayer wiring board, so wiring defects are likely to occur during the production of the multilayer wiring board.

[0049] The liquid-phase viscosity is preferably 10 4.0 dPa·s or more, 10 4.2 dPa·s or more, 10 4.6 dPa·s or more, 10 4.8 dPa·s or more, 10 5.0 dPa·s or more, particularly 10 5.2 dPa·s or more. If the liquid-phase viscosity is too low, the glass is likely to devitrify during molding.

[0050] The Young's modulus is preferably 40 GPa or higher, 41 GPa or higher, 43 GPa or higher, 45 GPa or higher, 47 GPa or higher, 50 GPa or higher, 51 GPa or higher, 52 GPa or higher, 53 GPa or higher, 54 GPa or higher, particularly 55 GPa or higher. If the Young's modulus is too low, the glass plate is likely to bend, so wiring defects are likely to occur during the production of the multilayer wiring board.

[0051] The β-OH value is preferably 1.1 mm -1 or less, 0.6 mm -1 or less, 0.55 mm -1 or less, 0.5 mm -1 or less, 0.45 mm -1 or less, 0.4 mm -1 or less, 0.35 mm -1 or less, 0.3 mm -1 or less, 0.25 mm -1 or less, 0.2 mm -1 or less, 0.15 mm -1 or less, particularly 0.1 mm -1The following holds. If the β-OH value is too large, it becomes difficult to ensure low dielectric characteristics. The "β-OH value" is a value calculated by the following mathematical formula using FT-IR.

[0052] β-OH value = (1 / X)log(T1 / T2) X: Plate thickness (mm) T1: Transmittance (%) at a reference wavelength of 3846 cm -1 T2: Minimum transmittance (%) in the vicinity of the hydroxyl absorption wavelength of 3600 cm -1

[0053] The glass plate of the present invention preferably has through-holes formed in the plate thickness direction. Also, from the viewpoint of increasing the wiring density, the inner diameter of the through-holes is preferably 200 μm or less, 180 μm or less, 150 μm or less, 130 μm or less, 120 μm or less, 100 μm or less, 50 μm or less, particularly 30 μm or less. However, if the average inner diameter of the through-holes is too small, it becomes difficult to form a wiring structure for establishing conduction between both surfaces of the glass plate. Therefore, the inner diameter of the through-holes is preferably 1 μm or more, 3 μm or more, 5 μm or more, 7 μm or more, particularly 10 μm or more.

[0054] As a method for forming small through-holes in the glass plate, various methods can be adopted. From the viewpoint of efficiently forming small through-holes, a method of forming a modified portion on the glass plate with a laser and then etching the modified portion to form through-holes is preferable. A method of forming fine through-holes in the glass plate and then expanding the opening region of these through-holes by etching is also preferable.

[0055] The difference between the maximum value and the minimum value of the inner diameter of the through-holes is preferably 100 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, particularly 25 μm or less. If the difference between the maximum value and the minimum value of the inner diameter of the through-holes is too large, the length of the wiring for establishing conduction between both surfaces of the glass plate becomes unnecessarily long, making it difficult to reduce transmission loss.

[0056] In the glass plate according to the present invention, the plate thickness is preferably 0.5 mm or less, 1 to 100 μm, 5 to 50 μm, particularly 10 to 30 μm. If the plate thickness is too large, the distance between the ground and the signal line increases, and the effective relative dielectric constant increases. Furthermore, it becomes difficult to form through holes in the glass plate, making it difficult to achieve high-density wiring in a multilayer wiring board. In addition, if the plate thickness is too small, it becomes difficult to handle the glass plate.

[0057] The glass plate according to the present invention is preferably formed by the overflow down-draw method. In this way, a glass plate with good surface quality without polishing can be efficiently obtained. In addition to the overflow down-draw method, various forming methods can be adopted. For example, forming methods such as the slot down method, the float method, and the roll out method can be adopted.

[0058] From the perspective of achieving fine wiring, the arithmetic mean roughness Ra of the surface of the glass plate is preferably 10 nm or less, 5 nm or less, 2 nm or less, 1 nm or less, 0.5 nm or less, particularly 0.2 nm or less. If the arithmetic mean roughness Ra of the surface of the glass plate is too large, it becomes difficult to achieve fine wiring. In addition, since the arithmetic mean roughness Ra of the wiring formed on the surface of the glass plate increases, the so-called resistance loss due to the skin effect that occurs when an electric current flows through the wiring of a high-frequency device becomes excessive. Also, the strength of the glass plate decreases, making it easier to break. Note that the "arithmetic mean roughness Ra" can be measured by a stylus-type surface roughness meter or an atomic force microscope (AFM).

[0059] The resin layer is preferably a prepreg in which a glass cloth is impregnated with a resin. If it is a prepreg in which a glass cloth is impregnated with a resin, it becomes easier to adjust the stretchability, strength, heat resistance, low dielectric characteristics, etc. depending on the glass composition and weaving method of the glass cloth, and the composition and blending amount of the impregnated resin. Furthermore, when this prepreg is stacked above and below a metal layer such as a copper foil and further heated and pressed while being sandwiched between the metal layers, the semi-cured resin of the prepreg can be remelted to serve as an adhesive. Note that an epoxy resin is generally used as the resin impregnated into the glass cloth.

[0060] In the laminate of the present invention, the relative permittivity of the resin layer at 25°C and a frequency of 28 GHz is preferably 5 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, particularly 4.5 or less. If the relative permittivity at 25°C and a frequency of 28 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0061] In the laminate of the present invention, the dielectric tangent of the resin layer at 25°C and a frequency of 28 GHz is preferably 0.01 or less, 0.009 or less, 0.008 or less, 0.007 or less, 0.006 or less, 0.005 or less, 0.004 or less, particularly 0.003 or less. If the dielectric tangent at 25°C and a frequency of 28 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0062] In the laminate of the present invention, the relative permittivity of the resin layer at 25°C and a frequency of 2.45 GHz is preferably 5 or less, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, particularly 4.5 or less. If the relative permittivity at 25°C and a frequency of 2.45 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

[0063] In the laminate of the present invention, the dielectric tangent of the resin layer at 25°C and a frequency of 2.45 GHz is preferably 0.01 or less, 0.009 or less, 0.008 or less, 0.007 or less, 0.006 or less, 0.005 or less, 0.004 or less, 0.003 or less, 0.002 or less, 0.001 or less, 0.0009 or less, 0.0008 or less, particularly 0.0007 or less. If the dielectric tangent at 25°C and a frequency of 2.45 GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase.

Examples

[0064] Hereinafter, the present invention will be described in detail based on examples. Note that the following examples are merely illustrative, and the present invention is not limited to the following examples at all.

[0065] Tables 1 to 3 show the examples (Sample Nos. 1 to 22, 24 to 32) and comparative example (Sample No. 23) of the present invention.

[0066]

Table 1

[0067]

Table 2

[0068]

Table 3

[0069] Samples Nos. 1 to 32 were prepared as follows. First, glass raw materials prepared to have the glass compositions in the table were put into a platinum crucible, melted at 1600 °C for 24 hours, and then poured onto a carbon plate to be formed into a flat plate shape. Next, for each of the obtained samples, the relative permittivity at 25 °C and a frequency of 2.45 GHz, the dielectric loss tangent at 25 °C and a frequency of 2.45 GHz, the relative permittivity at 25 °C and a frequency of 28 GHz, the dielectric loss tangent at 25 °C and a frequency of 28 GHz, density, coefficient of thermal expansion, strain point, annealing point, softening point, temperature at 10 4.0 dPa·s, temperature at 10 3.0 dPa·s, temperature at 10 2.5 dPa·s, liquidus temperature, liquidus viscosity, Young's modulus, rigidity modulus, Poisson's ratio, and β-OH value were evaluated.

[0070] The relative permittivity and dielectric loss tangent at 25 °C and a frequency of 2.45 GHz and the relative permittivity and dielectric loss tangent at 25 °C and a frequency of 28 GHz refer to the values measured by the well-known cavity resonator method.

[0071] Density is the value measured by the well-known Archimedes method.

[0072] The coefficient of thermal expansion is the value measured by a dilatometer and is the average value in the temperature range of 30 to 380 °C.

[0073] The skew point, the softening point, and the melting point are the values measured based on the methods of ASTM C336 and C338.

[0074] 10 4.0 The temperature at 10 3.0 The temperature at 10 2.5 The temperature at 10 dPa·s is the value measured by the platinum ball pulling-up method.

[0075] The liquidus temperature is the value measured by putting glass powder that passes through a standard sieve of 30 mesh (500 μm) and remains on a 50 mesh (300 μm) into a platinum boat and holding it in a temperature gradient furnace for 24 hours to measure the temperature at which crystals precipitate.

[0076] The liquidus viscosity is the value measured by the platinum ball pulling-up method for the viscosity of the glass at the liquidus temperature.

[0077] The Young's modulus and the rigidity modulus are the values measured by the resonance method. The Poisson's ratio is the value calculated from the Young's modulus and the rigidity modulus.

[0078] The β-OH value is the value measured by the above method.

[0079] As can be seen from the table, Samples No. 1 to 22, 24 to 32 have low dielectric characteristics and are suitable for high-frequency devices, but Sample No. 23 does not have low dielectric characteristics and is not suitable for high-frequency devices.

Example

[0080] The glass batches having the glass compositions of Sample Nos. 1 to 22 and 24 to 32 described in Tables 1 to 3 were melted in a test melting furnace to obtain molten glass. After that, they were formed and cut by the overflow down-draw method to form glass plates each having a thickness of 50 μm. When forming the glass plates, the surface roughness of the glass plates was adjusted by appropriately adjusting the speed of the pulling roller, the speed of the cooling roller, the temperature distribution of the heating device, the temperature of the molten glass, the flow rate of the molten glass, the sheet-drawing speed, the rotation speed of the stirring stirrer, etc. When the arithmetic mean roughness Ra of the surface of the obtained glass plate was measured with an atomic force microscope (AFM), it was 0.2 nm. Next, a plurality of through-holes were formed in the glass plate. The through-holes were produced by irradiating the surface of the glass plate with a commercially available picosecond laser to form a modified layer and then removing the modified layer by etching. When the inner diameters of the through-holes related to Sample Nos. 7 and 14 described in the table were measured, the maximum value was 85 μm, the minimum value was 62 μm, and the difference between the maximum value and the minimum value of the inner diameter was 23 μm in each case.

[0081] Next, a conductor circuit layer was formed on the inner peripheral surface of the through-holes of the glass plates related to Sample Nos. 1 to 22 and 24 to 32 described in Tables 1 to 3 by the semi-additive method. Specifically, production of a seed metal layer by sputtering, formation of a metal layer by electroless plating, formation of a resist pattern, and formation of copper plating for wiring were sequentially performed to form a conductor circuit layer.

[0082] Subsequently, after placing prepregs in which glass cloth was impregnated with an epoxy resin on both surfaces of the glass plates related to Sample Nos. 1 to 22 and 24 to 32 via an adhesive layer, they were laminated and integrated by thermocompression bonding to produce laminated plates having a three-layer structure of a resin layer, a glass plate, and a resin layer. In the prepregs, wirings made of a copper metal layer are formed on the inner peripheral surfaces of a plurality of through holes, and after the inner layer and the outer layer are connected by plating the inner peripheral surfaces of the through holes and the surfaces of the resin layers, a surface pattern is formed on the outermost layer. Next, through holes were mechanically formed in the thickness direction of the laminated plate, wirings made of a copper metal layer were formed on the inner peripheral surfaces thereof, and after plating the surfaces, the inner layer and the outer layer were connected. Then, a solder resist layer was formed on the outermost layer. Finally, external connection terminal portions were exposed by photolithography, plated, and then solder balls were formed to obtain multilayer wiring boards respectively.

Industrial Applicability

[0083] The laminated plate of the present invention is suitable for high-frequency compatible multilayer wiring boards, but in addition, it is also suitable as high-frequency filters (diplexers) and high-density semiconductor package boards that require low dielectric characteristics.

Claims

1. comprising at least one or more glass plates and at least one or more resin layers, The glass plate has, as a glass composition, in mol%, SiO ２ 60 to 90%, Al ２ O ３ 1 to 15%, B ２ O ３ 5 to 30%, and contains 0 to 8% of MgO + CaO + SrO + BaO, the relative permittivity of the glass plate at 25 °C and a frequency of 2.45 GHz is 5 or less, and the dielectric loss tangent of the glass plate at 25 °C and a frequency of 2.45 GHz is 0.003 or less, a laminated plate in which through holes are formed in the thickness direction of the glass plate.

2. The laminated plate according to claim 1, wherein the resin layer is a prepreg obtained by impregnating a glass cloth with a resin.

3. The laminated plate according to claim 1 or 2, wherein the thickness of the glass plate is 5 to 50 μm.

4. The laminated plate according to any one of claims 1 to 3, wherein the glass plate contains 0 to 8% of MgO and 0 to 8% of CaO in mol%.

5. The laminated plate according to any one of claims 1 to 4, wherein the inner diameter of the through hole formed in the glass plate is 200 μm or less.

6. The laminated plate according to any one of claims 1 to 5, wherein the difference between the maximum value and the minimum value of the inner diameter of the through hole formed in the glass plate is 100 μm or less.

7. The laminated plate according to any one of claims 1 to 6, wherein a metal layer is formed on the inner peripheral surface of the through hole formed in the glass plate.

8. The laminated plate according to any one of claims 1 to 7, which is used for a multilayer wiring board.

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