1. A core substrate,
comprising:
an electrically conductive core section having a pilot hole, through which a plated through-hole section is formed;
cable layers being respectively laminated on the both side faces of the core section;
a plated layer coating an inner face of the pilot hole; and
an insulating material filling a space between the plated layer and an outer circumferential face of the plated through-hole section.
2. The core substrate according to claim 1,
further comprising an insulating film coating the plated layer, which coats the inner face of the pilot hole.
3. The core substrate according to claim 1,
wherein the plated layer makes the inner face of the pilot hole smooth.
4. The core substrate according to claim 1,
wherein the plated layer encompasses electrically conductive accretions stuck on the inner face of the pilot hole.
5. The core substrate according to claim 1,
wherein the core section is composed of carbon fiber-reinforced plastic and formed into a flat plate by heating and pressurizing a plurality of prepregs including carbon fibers.
6. A method of producing a core substrate,
comprising the steps of:
forming a pilot hole in a substrate having an electrically conductive core section;
forming a plated layer on an inner face of the pilot hole;
filling the pilot hole, in which the plated layer has been formed, with an insulating material;
forming a through-hole in the pilot hole, which has been filled with the insulating material; and
forming a plated layer on an inner face of the through-hole so as to form a plated through-hole section.
7. The method according to claim 6,
wherein cable layers are integrally formed on the both side faces of the substrate after filling the pilot hole with the resin, and
the through-hole, which passes through the pilot hole, is formed in the substrate, on which the cable layers have been integrally formed.
8. The method according to claim 6,
wherein an insulating film is formed on the plated layer by an electrodeposition process, in which the plated layer is used as an electric power feeding layer, after forming the plated layer on the inner face of the through-hole by plating the substrate having the pilot hole.
9. The method according to claim 6,
wherein a plated layer, which makes the inner face of the pilot hole smooth, is formed when the substrate having the pilot hole is plated.
10. The method according to claim 6,
wherein a plated layer, which encompasses electrically conductive accretions stuck on the inner face of the pilot hole, is formed when the substrate having the pilot hole is plated.
11. The method according to claim 6,
wherein the core section is formed into a flat plate by the steps of: laminating a plurality of prepregs including carbon fibers; and heating and pressurizing the laminated prepregs.
12. A multi-layered circuit board,
comprising:
a core substrate including an electrically conductive core section having a pilot hole, through which a plated through-hole section is formed, cable layers being respectively laminated on the both side faces of the core section, a plated layer coating an inner face of the pilot hole, and an insulating material filling a space between the plated layer and an outer circumferential face of the plated through-hole section; and
a cable layer being laminated on the core substrate.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A boundary acoustic wave device comprising:
a piezoelectric substance;
a dielectric substance stacked on the piezoelectric substance; and
IDT electrodes arranged between the piezoelectric substance and the dielectric substance; wherein
the piezoelectric substance has a negative temperature coefficient of frequency;
the dielectric substance has a positive temperature coefficient of frequency;
each of the IDT electrodes includes:
a first conductive layer arranged on a side of the piezoelectric substance and composed of a metal with a relatively high density or an alloy primarily containing the metal;
a second conductive layer arranged on a side of the first conductive layer adjacent to the dielectric substance and composed of a metal with a relatively low density or an alloy primarily containing the metal; and
a third conductive layer arranged on a side of the second conductive layer adjacent to the dielectric substance and composed of a metal with a relatively high density or an alloy primarily containing the metal; wherein
if thicknesses of the first, second, and third conductive layers are H1, H2, and H3, and a period of the IDT electrodes is \u03bb, the following relationships are satisfied:
0.04\u03bb<H1+H3<0.12\u03bb
H1>0.009\u03bb, H3>0.022\u03bb
0.05\u03bb<H2<0.16\u03bb.
2. The boundary acoustic wave device according to claim 1, wherein the metal with a relatively high density or the alloy primarily containing the metal is one metal selected from Pt, Au, W, Ta, Cu, Ag, Ni, Fe, Cr, and Pd or an alloy primarily containing one metal among these metals, and the metal with a relatively low density or the alloy primarily containing the metal is one metal selected from Al, Mg, Ti, Cr, Ni, Cu, and Ag or an alloy primarily containing one metal among these metals, and wherein the metal with a relatively low density or the alloy primarily containing the metal is different from the metal with a relatively high density or the alloy primarily containing the metal.
3. The boundary acoustic wave device according to claim 1, wherein the first and third conductive layers are composed of Pt or an alloy primarily containing Pt, the second conductive layer is composed of Al or an alloy primarily containing Al, and the thicknesses H1 to H3 of the first to third conductive layers satisfy the following relationships:
0.04\u03bb<H1+H3<0.12\u03bb
H1>0.01\u03bb, H3>0.022\u03bb
0.05\u03bb<H2<0.15\u03bb.
4. The boundary acoustic wave device according to claim 1, wherein the first and third conductive layers are composed of Au or an alloy primarily containing Au, the second conductive layer is composed of Al or an alloy primarily containing Al, and the thicknesses H1 to H3 of the first to third conductive layers satisfy the following relationships:
0.04\u03bb<H1+H3<0.12\u03bb
H1>0.009\u03bb, H3>0.022\u03bb
0.05\u03bb<H2<0.15\u03bb.
5. The boundary acoustic wave device according to claim 1, wherein the first and third conductive layers are composed of Pt or an alloy primarily containing Pt, the second conductive layer is composed of Cu or an alloy primarily containing Cu, and the thicknesses H1 to H3 of the first to third conductive layers satisfy the following relationships:
0.06\u03bb<H1+H3<0.14\u03bb
H1>0.01\u03bb, H3>0.03\u03bb
0.07\u03bb<H2<0.16\u03bb.
6. The boundary acoustic wave device according to claim 1, wherein the first and third conductive layers are composed of Au or an alloy primarily containing Au, the second conductive layer is composed of Cu or an alloy primarily containing Cu, and the thicknesses H1 to H3 of the first to third conductive layers satisfy the following relationships:
0.04\u03bb<H1+H3<0.12\u03bb
H1>0.01\u03bb
H3>0.026\u03bb
0.05\u03bb<H2<0.14\u03bb.
7. The boundary acoustic wave device according to claim 1, wherein each of the IDT electrodes further includes an adhesive layer that has a higher adhesion to a target material than the adhesion of each of the first to third conductive layers to the target material, and wherein the adhesive layer is arranged at at least one selected from positions between the piezoelectric substance and the first conductive layer, between the dielectric substance and the third conductive layer, between the first and second conductive layers, and between the second and third conductive layers.
8. The boundary acoustic wave device according to claim 1, wherein each of the IDT electrodes further includes a diffusion barrier layer that prevents the diffusion of the metals or the alloys constituting the electrodes, and wherein the diffusion barrier layer is arranged at at least one of positions between the piezoelectric substance and the first conductive layer, between the third conductive layer and the dielectric substance, between the first and second conductive layers, and between the second and third conductive layers.
9. The boundary acoustic wave device according to claim 1, wherein the piezoelectric substance is LiNbO3 and has Euler angles (\u03c6, \u03b8, \u03c6) of (\u22125\xb0<\u03c6<5\xb0, 100\xb0<\u03b8<110\xb0, \u221230\xb0<\u03c6<30\xb0), and the dielectric substance is composed of silicon oxide.