Multilayer circuit board, process of manufacturing same, board for multilayer circuitry, and electronic apparatus

A process of manufacturing a multilayer circuit board in which at least one insulating layer and a plurality of wiring layers separated from one another by the insulating layer are laminated, the process comprising the steps of:

• forming a wiring on the wiring layer in a composite material including the wiring layer and the insulating layer integrally formed on the wiring layer, the wiring layer including a second metal layer formed on one or both sides of a first metal layer,
• wherein the second metal layer has a larger coefficient of thermal expansion than the first metal layer;
• forming a blind via-hole in the insulating layer such that a bottom portion of the via-hole is formed by a surface of the second metal layer;
• forming a layer-to-layer interconnection portion on the surface of the insulating layer, and in the blind via-hole and the composite material and the wiring layers are in a layer-to-layer interconnection with one another through a layer-to-layer interconnection portion which is in contact with the second metal layer formed in the blind via-hole.

A process of manufacturing multilayer circuit board comprising an insulating layer in which at least one wiring layer is formed, the process comprising the steps of:

• forming a wiring on the wiring layer in a composite material including the wiring layer and the insulating layer integrally formed on the wiring layer, the wiring layer comprising a second metal layer formed on one or both sides of a first metal layer,
• wherein the second metal layer has a larger coefficient of thermal expansion than the first metal layer;
• forming a blind via-hole in each insulating layer on the opposite surface between which the wiring layer is inserted, the blind via-hole having a bottom portion formed by a surface of the second metal layer;
• and
• forming a layer-to-layer interconnection portion on the surface of the insulating layers in each blind via-hole and the composite material and wiring layers are in a layer-to-layer interconnection with one another through a layer-to-layer interconnection portion which is in contact with the second metal metal layer formed in the blind via-hole.

A process of manufacturing a multilayer circuit board comprising the steps of:

• preparing a wiring layer formed by a composite material including a first metal layer and a second metal layer formed on one or both sides of the first metal layer, the second metal layer having a higher electric conductivity and a greater coefficient of thermal expansion than the first metal layer;
• forming a substrate for multilayer circuitry by laminating the wiring layer on one or both sides of an insulating resin layer;
• forming a predetermined wiring on the wiring layer;
• covering the wiring formed in the wiring forming step with an insulating layer;
• forming a blind via-hole in the insulating layer, or the insulating layer and insulating resin layer, the blind via-hole having a bottom portion formed by a surface of the second metal layer;
• and forming a layer-to-layer interconnection portion on the surface of the insulating layer and in the blind via-hole and the composite material and wiring layers are in a layer-to-layer interconnection with one another through a layer-to-layer interconnection portion which is in contact with the second metal layer formed in the blind via-hole.

A process of manufacturing a multilayer circuit board comprising the steps of:

• preparing a wiring layer formed by a composite material comprising a first metal layer and a second metal layer formed on both sides of the first metal layer, the second metal layer having a higher electric conductivity and a greater coefficient of thermal expansion than the first metal layer;
• forming a substrate for multilayer circuitry by laminating the wiring layer on both sides of an insulating layer;
• forming a predetermined wiring on the wiring layer formed in the wiring preparing step;
• covering the wiring formed in the wiring forming step with an insulating layer;
• forming a blind via-hole in each insulating layer, or the insulating layer and insulating resin layer on the opposite surfaces between which the insulating layer is inserted, the blind via-hole having a bottom portion formed by a surface of the second metal layer;
• and
• forming a layer-to-layer interconnection portion on the surface of the insulating layer and in the blind via-hole and the composite material and wiring layers are in a layer-to-layer interconnection with one another through a layer-to-layer interconnection portion which is in contact with the second metal layer formed in the blind via-hole.