Circuit board and method of manufacturing circuit board
A circuit board includes a substrate, a first circuit layer, a second circuit layer, and a third circuit layer. The substrate includes a base layer, a first metal layer formed on the base layer, and a seed layer formed on the first metal layer. The first circuit layer is located on the substrate and includes the first metal layer and a signal layer formed on a surface of the first metal layer. The second circuit layer is coupled to the first circuit layer and includes the first metal layer, the seed layer, and a connection pillar formed on a surface of the first metal layer and the seed layer. The third circuit layer is coupled to the second circuit layer and includes the seed layer and a coil formed on a surface of the seed layer.
1. A circuit board comprising:
a substrate comprising a base layer, a first metal layer formed on the base layer, and a seed layer formed on the first metal layer;
a first circuit layer located on the substrate and comprising the first metal layer and a signal layer formed on a surface of the first metal layer;
a second circuit layer coupled to the first circuit layer and comprising the first metal layer, the seed layer, and a connection pillar formed on a surface of the first metal layer and the seed layer; and
a third circuit layer coupled to the second circuit layer and comprising the seed layer and a coil formed on a surface of the seed layer.
2. The circuit board of claim 1 , wherein:
the seed layer is formed on a surface of the first metal layer.
3. The circuit board of claim 1 , wherein:
a sheet resistance of the first metal layer is greater than a sheet resistance of the seed layer.
4. The circuit board of claim 1 , wherein:
the circuit board is folded at the first circuit layer to form a rectangular structure comprising four coils, the four coils facing each other in pairs.
5. The circuit board of claim 1 , wherein:
a material of the base layer is selected from at least one of polyimide, liquid crystal polymer, polyethylene terephthalate, and polyethylene naphthalate.
6. The circuit board of claim 1 , wherein:
a material of the first metal layer is a combination of Ni—P or NiCr oxide; and
a material of the second metal layer is Cu.