Multilayer wiring board, and method for manufacturing multilayer wiring board
A multilayer wiring board has a central wiring layer disposed in the center of an odd number of wiring layers, insulating layers and wiring layers disposed above and below the central wiring layer, respectively, an interlayer connections having cross-sectionally trapezoidal shapes and penetrating the insulating layers to establish interlayer connection between the wiring layers. The interlayer connection is disposed to connect to a portion below the central wiring layer. The interlayer connection is disposed to connect to a portion above the central wiring layer. The directions of tapers of the cross-sectionally trapezoidal shapes of the interlayer connections are identical.
1. A multilayer wiring board comprising:
an odd number of wiring layers comprising:
a first wiring layer consisting essentially of a metal foil;
a first insulating layer disposed on the first wiring layer;
a central wiring layer disposed on the first insulating layer opposite the first wiring layer, the central wiring layer comprising:
a first side;
a second side opposite the first side;
a metal foil layer; and
a plating layer comprising a first interlayer connection, the first interlayer connection having a cross-sectionally trapezoidal shape comprising a taper penetrating the first insulating layer to establish interlayer connection between the central wiring layer and the first wiring layer,
wherein the metal foil layer of the central wiring layer is thinner than the first wiring layer;
a second insulating layer disposed on the central wiring layer opposite the first insulating layer;
a second wiring layer disposed on-the second insulating layer opposite the central wiring layer, the second wiring layer comprising:
a metal foil layer; and
a plating layer comprising a second interlayer connection, the second interlayer connection having a cross-sectionally trapezoidal shape comprising a taper penetrating the second insulating layer to establish interlayer connection between the central wiring layer and the second wiring layer,
wherein the first interlayer connection is disposed so as to connect to the first side of the central wiring layer and the second interlayer connection is disposed so as to connect to the second side of the central wiring layer, and direction of the tapers of the cross-sectionally trapezoidal shapes of the first and second interlayer connections are identical,
a third insulating layer disposed on the first wiring layer of the odd number of wiring layers opposite the first insulating layer of the odd number of wiring layers; and
a third wiring layer disposed on the third insulating layer opposite the first wiring layer of the odd number of wiring layers,
a third interlayer connection having a cross-sectionally trapezoidal shape comprising a taper penetrating the third insulating layer to establish interlayer connection between the first wiring layer of the odd number of wiring layers and the third wiring layer, wherein the third interlayer connection penetrates the third wiring layer,
wherein the direction of the taper of the cross-sectionally trapezoidal shapes of each of the first and second interlayer connections and a direction of the taper of the cross-sectionally trapezoidal shape of the third interlayer connection are opposite each other,
a fourth insulating layer disposed on the second wiring layer of the odd number of wiring layers opposite the second insulating layer; and
a fourth wiring layer disposed on the fourth insulating layer opposite the second wiring layer of the odd number of wiring layers, and
a fourth interlayer connection having a cross-sectionally trapezoidal shape comprising a taper penetrating the fourth insulating layer to establish interlayer connection between the second wiring layer of the odd number of wiring layers and the fourth wiring layer,
wherein the direction of the taper of the cross-sectionally trapezoidal shapes of each of the first and second interlayer connects and a direction of the taper of the cross-sectionally trapezoidal shape of the fourth interlayer connection are identical, and
wherein each outermost layer of the multilayer wiring board is a wiring layer including a circuit pattern.
2. The multilayer wiring board according to claim 1 , wherein the outermost layers are the third wiring layer and the fourth wiring layer.
3. The multilayer wiring board according to claim 1 , wherein the thickness of the first wiring layer is 1 μm to 9 μm.
4. The multilayer wiring board according to claim 1 , wherein the metal foil layer of the second wiring layer is thinner than the first wiring layer.
5. The multilayer wiring board according to claim 1 , wherein the first insulating layer includes a prepreg.
6. The multilayer wiring board according to claim 1 , wherein the second insulating layer includes a prepreg.
7. The multilayer wiring board according to claim 1 , wherein a metal foil layer of the third wiring layer is thinner than the first wiring layer.
8. The multilayer wiring board according to claim 1 , wherein a metal foil layer of the fourth wiring layer is thinner than the first wiring layer.
9. The multilayer wiring board according to claim 1 , wherein a thickness of the first wiring layer is more than double a thickness of the metal foil layer of the central wiring layer.
10. The multilayer wiring board according to claim 1 , wherein the metal foil layer of the second wiring layer is thinner than the first wiring layer, a metal foil layer of the third wiring layer is thinner than the first wiring layer, and a metal foil layer of the fourth wiring layer is thinner than the first wiring layer.