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 multilayer wiring boards compatible with high-frequency communication. [Background technology]

[0002] Currently, development is underway to support the fifth-generation mobile communication system (5G), and technical studies are being conducted to increase system speed, transmission capacity, and latency. Multilayer printed circuit boards used in this application are also required to reduce transmission loss in high-frequency communications. [Disclosure of the Invention] [Problems that the invention aims to solve]

[0003] In recent years, with the increasing sophistication of electronic devices, the wiring in multilayer printed circuit boards has become finer. To accommodate this, multilayer printed circuit boards require a core layer with good surface flatness and excellent dimensional stability. However, current resin layers made by impregnating glass cloth with resin do not provide sufficient surface smoothness and dimensional stability.

[0004] The present invention has been made in view of the above circumstances, and its technical objective is to provide a laminate that has low dielectric properties and contributes to high-density wiring. [Means for solving the problem]

[0005] The present inventors, after conducting various experiments, have found that the above technical problems can be solved by laminating a glass plate having low dielectric properties with a resin layer, and propose this as the present invention. Specifically, the laminate of the present invention comprises at least one glass plate and at least one resin layer, and is characterized in that 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. This makes it possible to reduce transmission loss 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 the well-known cavity resonator method. The "dielectric loss tangent at 25°C and a frequency of 2.45 GHz" can be measured, for example, by the well-known cavity resonator method.

[0006] The laminate of the present invention comprises at least one glass plate. The glass plate is suitable as the core layer of a multilayer wiring board, and the inclusion of the glass plate provides the following effects: Since the thermal expansion coefficient of the glass plate is lower than that of the resin, the difference in thermal expansion coefficients between the glass plate and the silicon, which is the material of the semiconductor chip, can be reduced. This reduces stress on the connection part during chip mounting and improves connection reliability. In addition, since the glass plate has higher flatness than the resin, it is advantageous for forming fine wiring. Furthermore, the glass plate expands and contracts less due to heat and moisture absorption than the resin and has excellent dimensional stability. This reduces positional displacement of patterns during photolithography and via formation, which is advantageous for forming fine wiring.

[0007] The laminate of the present invention comprises at least one glass plate and at least one resin layer. This allows for high-density wiring of a multilayer wiring board by using the glass plate as a core layer and further laminating the resin layer.

[0008] In the laminate of the present invention, the relative permittivity of the glass plate at 25°C and a frequency of 2.45GHz is 5 or less, and the dielectric loss tangent of the glass plate at 25°C and a frequency of 2.45GHz is 0.003 or less. This makes it possible to reduce transmission loss 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, the thickness of the glass plate is preferably 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. Also, the propagation speed of an electrical signal is calculated by V = C / √ε, but the relative permittivity changes depending on the signal line width of the laminate and 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 a multilayer wiring board.

[0013] In addition, in the laminate of the present invention, the glass plate preferably 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 taking 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. This makes it easier to increase the density of the wiring structure for establishing conduction between both surfaces of the glass plate.

[0016] Further, 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. This can prevent the situation where the wiring for establishing conduction between both surfaces of the glass plate becomes unduly long, and thus the transmission loss can be reduced.

[0017] Moreover, 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] Furthermore, 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 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 achieved. 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 enhanced. 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.

[0020] The number of glass plates is one or more, preferably two or more, particularly 3 to 20 layers, and the number of resin layers is one or more, preferably three or more, particularly 5 to 30 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 the glass plate. The metal layer can be used as wiring. Considering low resistivity, cost, and availability, the metal layer preferably contains one or more of the following: copper, silver, gold, aluminum, molybdenum, tungsten, nickel, tin, and alloys thereof, and is particularly preferably copper or an alloy containing copper.

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

[0023] The preferred lower limit content of SiO2 is 60%, 61%, 62%, 63%, 64%, 65%, and especially 66%, while the preferred upper limit content is 90%, 85%, 80%, 75%, 73%, 71%, 70%, and especially 69%. If the SiO2 content is too low, the dielectric constant, dielectric loss tangent, and density tend to increase. Also, the moisture resistance tends to decrease. On the other hand, if the SiO2 content is too high, the high-temperature viscosity increases, reducing meltability, and devitrified crystals such as cristobalite tend to precipitate during molding.

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

[0025] B2O3 is a component that reduces the dielectric constant and dielectric loss tangent, but it also reduces Young's modulus and density. It is also a component that reduces moisture resistance. However, if the B2O3 content is too low, it becomes difficult to ensure low dielectric properties, and its function as a flux becomes insufficient, leading to high-temperature viscosity and a decrease in foam quality. Furthermore, it becomes difficult to achieve low density. Therefore, the suitable lower limit of B2O3 content is 5%, 10%, 15%, 18%, 20%, 21%, 22%, 23%, and especially 24%. On the other hand, if the B2O3 content is too high, heat resistance and chemical durability tend to decrease, and moisture resistance tends to decrease due to phase separation. Therefore, the suitable upper limit of B2O3 content is 30%, 29%, 28%, 27%, and especially 26%.

[0026] The B2O3-Al2O3 content 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, and especially 24% or more. If the B2O3-Al2O3 content is too low, it becomes difficult to ensure low dielectric properties. Note that "B2O3-Al2O3" is the B2O3 content minus the Al2O3 content.

[0027] Alkaline earth metal oxides are components that lower the liquidus temperature, making it difficult for devitrified crystals to form in glass, and also enhance meltability and moldability. If the content of MgO+CaO+SrO+BaO is too low, the devitrification resistance tends to decrease, and it cannot fully exert its function as a flux, leading to decreased meltability. On the other hand, if the content of MgO+CaO+SrO+BaO is too high, the dielectric constant and dielectric loss tangent increase, the density increases, making it difficult to lighten the glass, and the coefficient of thermal expansion becomes excessively high, leading to decreased thermal shock resistance. 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%, and especially 3%, while the preferred upper limit content is 6%, 5.5%, 5%, 4.8%, 4.6%, 4.4%, 4.2%, and especially 4%.

[0028] MgO is a component that lowers high-temperature viscosity and increases melting properties without lowering the strain point, and is also the component that least increases density among alkaline earth metal oxides. Furthermore, among alkaline earth metals, it is a component that particularly enhances moisture resistance. However, if the MgO content is too high, the liquidus temperature rises, and devitrification resistance tends to decrease. Also, the glass tends to split into phases, and transparency tends to decrease. The preferred lower limit of MgO content is 0%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and especially 1%, while the preferred upper limit is 8%, 5%, 4%, 3%, 2.5%, and especially 2%.

[0029] CaO is a component that significantly improves meltability by lowering high-temperature viscosity without reducing the strain point, and is also a component that greatly enhances devitrification resistance in the glass composition system according to the present invention. Furthermore, among alkaline earth metals, it is also a component that improves moisture resistance. Therefore, the preferred lower limit content of CaO is 0%, 0.5%, 1%, 1.5%, 2%, and especially 2.5%, and the preferred upper limit content is 8%, 5%, 4.5%, 4%, 3.5%, and especially 3%.

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

[0031] BaO is a component that lowers high-temperature viscosity and improves melting without lowering the strain point. However, if the BaO content is too high, the liquid phase viscosity tends to decrease. Therefore, the BaO content is preferably 0-5%, 0-4%, 0-3%, 0-2%, 0-1.5%, 0-1%, 0-0.5%, and especially less than 0-0.1%.

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

[0033] Alkali metal oxides are components that enhance melting and moldability, but if their content is too high, the density increases, water resistance decreases, the coefficient of thermal expansion becomes unreasonably high, thermal shock resistance decreases, and it becomes difficult to match the coefficient of thermal expansion of surrounding materials. Therefore, the combined amount of Li2O, Na2O, and K2O is 0-3%, preferably 0-2%, 0-1%, 0-0.5%, 0-0.2%, 0-0.1%, and particularly less than 0.001-0.05%. The individual contents of Li2O, Na2O, and K2O are preferably 0-3%, 0-2%, 0-1%, 0-0.5%, 0-0.2%, 0-0.1%, and particularly less than 0.001-0.01%.

[0034] ZnO is a component that enhances meltability, but if it is included in large quantities in the glass composition, the glass becomes more prone to devitrification and its density tends to increase. Therefore, the ZnO content is preferably 0-5%, 0-3%, 0-0.5%, 0-0.3%, and particularly 0-0.1%.

[0035] ZrO2 is a component that increases Young's modulus. The ZrO2 content is preferably 0-5%, 0-3%, 0-0.5%, 0-0.2%, 0-0.16%, 0-0.1%, and especially 0-0.02%. If the ZrO2 content is too high, the liquid phase temperature will rise, making it easier for devitrified zircon crystals to precipitate.

[0036] TiO2 is a component that lowers high-temperature viscosity and increases meltability, as well as suppressing solarization. However, if it is included in large quantities in the glass composition, the glass tends to become discolored and its transmittance decreases. Therefore, the TiO2 content is preferably 0-5%, 0-3%, 0-1%, 0-0.1%, and particularly 0-0.02%.

[0037] P2O5 is a component that enhances resistance to devitrification, but if it is included in large quantities in the glass composition, the glass may undergo phase separation, making it prone to milky whitening, and its water resistance may be significantly reduced. Therefore, the P2O5 content is preferably 0-5%, 0-1%, 0-0.5%, and particularly 0-0.1%.

[0038] Fe2O3 is a component that can be introduced as an impurity component or a clarifying agent component. However, if the Fe2O3 content is too high, the ultraviolet transmittance may decrease. Therefore, the Fe2O3 content is preferably 0.05% or less, 0.03% or less, and particularly 0.02% or less. Here, "Fe2O3" as used in this invention includes divalent iron oxide and trivalent iron oxide, and divalent iron oxide shall be treated as equivalent to Fe2O3. Other oxides shall also be treated in the same manner, based on the oxide indicated.

[0039] SnO2 is a component that exhibits good clarification properties in the high-temperature range, as well as a component that reduces high-temperature viscosity. The SnO2 content is preferably 0-1%, 0.01-0.5%, and particularly 0.05-0.2%. If the SnO2 content is too high, devitrified SnO2 crystals tend to precipitate in the glass.

[0040] As a clarifying agent, the addition of SnO2 is preferable, but as long as the glass properties are not impaired, CeO2, SO3, C, and metal powders (e.g., Al, Si, etc.) may be added in amounts up to 1%.

[0041] As2O3, Sb2O3, F, and Cl also act effectively as clarifying agents, and the present invention does not exclude the inclusion of these components. However, from an environmental standpoint, it is preferable that the content of each of these components be less than 0.1%, and 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 28GHz 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 permittivity at 25°C and 28GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends 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, 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 permittivity 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.

[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, 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 thermal expansion coefficient 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, particularly 35×10 -7 ~39×10 -7The coefficient of thermal expansion is / °C. If the coefficient of thermal expansion in the temperature range of 30 to 380°C falls outside this range, the difference in thermal expansion with silicon, the material of the semiconductor chip, becomes large. This increases the stress on the connection points during chip mounting, and 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, and particularly 590°C or higher. If the strain point is too low, the glass plate is more likely to shrink due to heat during the heat treatment process when manufacturing the multilayer printed circuit board, which makes wiring defects more likely to occur during the manufacturing of the multilayer printed circuit board.

[0049] The liquid phase viscosity is preferably 10 4.0 dPa·s or higher, 10 4.2 dPa·s or higher, 10 4.6 dPa·s or higher, 10 4.8 dPa·s or higher, 10 5.0 dPa·s or higher, especially 10 5.2 The viscosity should be dPa·s or higher. If the liquid-phase viscosity is too low, the glass is more 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, and especially 55 GPa or higher. If the Young's modulus is too low, the glass plate will bend easily, which increases the likelihood of wiring defects during the manufacturing of multilayer printed circuit boards.

[0051] The β-OH value is preferably 1.1 mm -1 Below, 0.6mm -1 Below, 0.55mm -1 Below, 0.5mm -1 Below, 0.45mm -1 Below, 0.4mm -1 Below, 0.35mm -1 Below, 0.3mm -1 Below, 0.25mm -1 Below, 0.2mm -1 Below, 0.15mm -1 The following, especially 0.1mm -1The following applies: If the β-OH value is too large, it becomes difficult to ensure low dielectric properties. Note that the "β-OH value" is a value calculated using FT-IR with the following formula.

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

[0053] The glass plate of the present invention preferably has through holes formed in the thickness direction. Furthermore, from the viewpoint of increasing 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, and 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 electrical conductivity between the two 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, and particularly 10 μm or more.

[0054] Various methods can be used to form small through-holes in a glass plate. However, from the viewpoint of efficiently forming small through-holes, a method is preferred in which a modified portion is formed in the glass plate with a laser, and then the modified portion is etched to form the through-hole. A method is also preferred in which fine through-holes are formed in the glass plate, and then the opening area of ​​these through-holes is enlarged by etching.

[0055] The difference between the maximum and minimum inner diameters 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, and especially 25 μm or less. If the difference between the maximum and minimum inner diameters of the through-holes is too large, the length of the wiring required to provide conductivity between the two 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, and 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 dielectric constant rises. Furthermore, it becomes difficult to form through holes in the glass plate, making high-density wiring of multilayer wiring boards difficult. If the plate thickness is too small, the glass plate becomes difficult to handle.

[0057] The glass plate according to the present invention is preferably formed by the overflow down-draw method. This method allows for the efficient production of glass plates with good surface quality without polishing. In addition to the overflow down-draw method, various other forming methods can be employed. For example, forming methods such as the slot-down method, float method, and roll-out method can be used.

[0058] From the perspective of achieving miniaturization of wiring, the arithmetic mean roughness Ra of the glass plate surface is preferably 10 nm or less, 5 nm or less, 2 nm or less, 1 nm or less, 0.5 nm or less, and particularly 0.2 nm or less. If the arithmetic mean roughness Ra of the glass plate surface is too large, it becomes difficult to achieve miniaturization of wiring. Also, because the arithmetic mean roughness Ra of the wiring formed on the surface of the glass plate is large, the resistance loss due to the so-called skin effect that occurs when current is passed through the wiring of a high-frequency device becomes excessive. In addition, the strength of the glass plate decreases and it becomes more prone to breakage. 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 made by impregnating glass cloth with resin. If a prepreg is made by impregnating glass cloth with resin, it becomes easier to adjust properties such as elasticity, strength, heat resistance, and low dielectric properties by controlling the glass composition and weaving method of the glass cloth, and the composition and amount of the impregnating resin. Furthermore, by layering this prepreg above and below a metal layer such as copper foil, and then heating and pressurizing it while sandwiched between the metal layers, the semi-cured resin in the prepreg remelts, allowing it to act as an adhesive. Epoxy resin is generally used as the resin impregnating 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 28GHz 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 permittivity at 25°C and a frequency of 28GHz 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 loss tangent of the resin layer at 25°C and a frequency of 28GHz 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 loss tangent at 25°C and a frequency of 28GHz 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, and 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 loss tangent of the resin layer at 25°C and a frequency of 2.45GHz 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, and particularly 0.0007 or less. If the dielectric loss tangent at 25°C and a frequency of 2.45GHz is too high, the transmission loss when an electrical signal is transmitted to a high-frequency device tends to increase. [Examples]

[0064] The present invention will be described in detail below based on the following examples. Note that the following examples are merely illustrative. The present invention is not limited in any way to the following examples.

[0065] Tables 1-3 show examples of the present invention (samples No. 1-22, 24-32) and comparative examples (sample No. 23).

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] Samples No. 1 to 32 were prepared as follows. First, glass raw materials, prepared to match the glass composition shown in the table, were placed in a platinum crucible and melted at 1600°C for 24 hours. After melting, the mixture was poured onto a carbon plate and formed into a flat plate. Next, for each obtained sample, the relative permittivity at 25°C and 2.45 GHz, dielectric loss tangent at 25°C and 2.45 GHz, relative permittivity at 25°C and 28 GHz, dielectric loss tangent at 25°C and 28 GHz, density, thermal expansion coefficient, strain point, annealing point, softening point, and 10 4.0 Temperature in dPa·s, 10 3.0 Temperature in dPa·s, 10 2.5 Temperature, liquidus temperature, liquidus viscosity, Young's modulus, shear modulus, Poisson's ratio, and β-OH value at dPa·s were evaluated.

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

[0071] The density was measured using the well-known Archimedes method.

[0072] The coefficient of thermal expansion is a value measured with a dilatometer and is an average value over a temperature range of 30 to 380°C.

[0073] The strain point, slow cooling point, and softening point were measured according to the ASTM C336 and C338 methods.

[0074] 10 4.0 Temperature in dPa·s, 10 3.0 Temperature and 10 in dPa·s 2.5 The temperature in dPa·s was measured using the platinum ball pulling method.

[0075] The liquidus temperature was measured by placing glass powder that passed through a standard 30-mesh (500 μm) sieve and remained in a 50-mesh (300 μm) sieve into a platinum boat and holding it in a temperature gradient furnace for 24 hours to determine the temperature at which crystals precipitated.

[0076] Liquid-phase viscosity is the viscosity of glass at liquid-phase temperature, measured using the platinum ball pulling method.

[0077] Young's modulus and shear modulus are values ​​measured using the resonance method. Poisson's ratio is a value calculated from Young's modulus and shear modulus.

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

[0079] As can be seen from the table, samples No. 1-22 and 24-32 have low dielectric properties and are suitable for high-frequency devices, but sample No. 23 does not have low dielectric properties and is unsuitable for high-frequency devices. [Examples]

[0080] Glass batches with the glass compositions of samples No. 1-22 and 24-32, as listed in Tables 1-3, were melted in a test melting furnace to obtain molten glass. This molten glass was then formed and cut using the overflow down-draw method to create glass plates with a thickness of 50 μm. During the formation of the glass plates, the surface roughness of the plates was adjusted by appropriately controlling the speed of the tension rollers, the speed of the cooling rollers, the temperature distribution of the heating device, the temperature of the molten glass, the flow rate of the molten glass, the plate drawing speed, and the rotation speed of the stirring stirrer. The arithmetic mean roughness Ra of the obtained glass plates was measured using an atomic force microscope (AFM) and found to be 0.2 nm. Next, multiple through-holes were formed in the glass plates. The through-holes were created by irradiating the surface of the glass plate with a commercially available picosecond laser to form a modified layer, and then removing this modified layer by etching. When the inner diameters of the through-holes in samples No. 7 and 14, as listed in the table, were measured, the maximum value was 85 μm, the minimum value was 62 μm, and the difference between the maximum and minimum inner diameters was 23 μm.

[0081] Next, a conductive circuit layer was formed on the inner circumferential surface of the through-holes in the glass plates corresponding to samples No. 1-22 and 24-32, as shown in Tables 1-3, using a semi-additive method. Specifically, the conductive circuit layer was formed by sequentially creating a seed metal layer by sputtering, forming a metal layer by electroless plating, forming a resist pattern, and forming copper plating for wiring.

[0082] Next, prepregs, which consisted of glass cloth impregnated with epoxy resin, were placed on both surfaces of the glass plates corresponding to samples No. 1-22 and 24-32 via an adhesive layer. These were then laminated and integrated by thermocompression bonding to create a three-layer laminate consisting of a resin layer, a glass plate, and another resin layer. In the prepreg, wiring made of copper metal layers was formed on the inner circumferential surface of multiple through holes. After the inner and outer layers were connected by plating on the inner circumferential surface of the through holes and the surface of the resin layer, a surface pattern was formed on the outermost layer. Next, through holes were mechanically drilled in the thickness direction of the laminate, wiring made of copper metal layers was formed on the inner circumferential surface, and the surface was plated to connect the inner and outer layers. After that, a solder resist layer was formed on the outermost layer. Finally, the external connection terminals were exposed by photolithography, plated, and then solder balls were formed to obtain multilayer wiring boards. [Industrial applicability]

[0083] The laminate of the present invention is suitable for high-frequency multilayer wiring boards, but is also suitable for high-frequency filters (diplexers) and high-density semiconductor package boards where low dielectric properties are required.

Claims

1. It includes at least one glass plate and at least one resin layer, The glass plate has a glass composition of SiO in mol%. ２ 60-75%, Al ２ O ３ 1-9%, B ２ O ３ It contains 20-27% B₂O₃-Al₂O₃, 18% or more 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 laminate according to claim 1, wherein the resin layer is a prepreg obtained by impregnating glass cloth with resin.

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

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

5. A laminate 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. A laminate according to any one of claims 1 to 5, wherein the difference between the maximum and minimum inner diameters of the through holes formed in the glass plate is 100 μm or less.

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

8. A laminate according to any one of claims 1 to 7, for use in a multilayer wiring board.

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