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US 8,476,536 B2Granted
Wiring substrate and method for manufacturing the same
AssigneeShinko Electric Industries Co., Ltd.
InventorsKentaro Kaneko, Kotaro Kodani, Junichi Nakamura, Kazuhiro Kobayashi
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Abstract
A wiring substrate has pads formed from a plurality of metal layers and vias connected to the pads. The plurality of metal layers have a metal layer exposed through the wiring substrate, and a first metal layer which is interposed between the metal layer and the vias and which prevents diffusion of metal included in the vias into the metal layer. A second metal layer which is less subject to oxidation than the first metal layer is provided between the vias and the first metal layer, and the vias are connected to the second metal layer.
Claims21
A wiring substrate comprising:
- an insulation layer;
- a pad including a plurality of metal layers, the pad disposed in the insulation layer;
- and
- a via connected to the pad,
- wherein the plurality of metal layers include a metal layer forming the lowermost layer of the pad exposed through the wiring substrate, a first metal layer which is interposed between the metal layer and the via and which prevents diffusion of metal included in the via into the metal layer, and a second metal layer which is less subject to oxidation than the first metal layer and which is provided between the via and the first metal layer,
- wherein the via is connected to the second metal layer,
- wherein an upper surface of the second metal layer at an interface with the via is a roughened surface that is rougher than an initial roughness of the upper surface so as to provide an improved electric contact and adhesion between the via and the second metal layer, an oxide film not being formed on the roughened surface of the second metal layer, and
- wherein the metal layer is made using any one of a Au layer, a Sn layer, and a SnAg layer.
5 more elements
A method for manufacturing a wiring substrate comprising:
- providing an insulation layer;
- a pad formation process for forming a pad including a plurality of metal layers in the insulation layer, the plurality of metal layers including a metal layer forming the lowermost layer of the pad exposed through the wiring substrate, a first metal layer which is provided on the metal layer and which prevents diffusion of metal included in a via into the metal layer, and a second metal layer which is provided on the first metal layer and which is less subject to oxidation than the first metal layer, the metal layer is made using any one of a Au layer, a Sn layer, and a SnAg layer;
- and
- a via and wiring formation process for forming integrally the via on the second metal layer and the wiring on a surface of the insulation layer,
- wherein the pad formation process further comprises,
- roughening a surface of the second metal layer at an interface for the via so that the surface is rougher than an initial roughness of the surface to provide an improved electric contact and adhesion between the via and the second metal layer, an oxide film not being formed on the roughened surface of the second metal layer,
- forming the pad on a supporting plate by forming the metal layer on the supporting plate, then the first metal layer on the metal layer, and then the second metal layer on the first metal layer by plating,
- wherein providing the insulation layer further comprises:
- forming the insulation layer over the supporting plate and the pad so that the insulation layer covers an upper surface of the second metal layer and a side surface of the pad, and
- forming an opening section in the insulation layer so that the upper surface of the second metal layer is exposed,
- wherein the via and wiring formation process further comprises forming the via in the opening section of the insulation layer so that the via connects to second metal layer,
- said method further comprising,
- removing the supporting plate so as to expose another surface of the insulation layer and a surface of the metal layer of the pad.
10 more elements
Dependencies are inferred from the claim text.