JingHongYi PCB (HK) Co., Limited
Printed Circuit Board,4 Layer PCB,4 Layer PCB Board,4 Layer Printed Circuit Board
4 layer PCB stackup include two inner layers, inner layer 1 and 2, are sandwiched between the top and bottom layers. From top to bottom, the 4-layer PCB stackup like below ,The top, i.e. the signal layer (0.0014 in. width) is followed by a prepreg layer with a thickness of 0.0091 in. and dielectric constant of 4.2. The top layer is copper material. The prepreg layer is followed by inner layer 1 (0.0014 in.), referred to as the plane. A core sublayer is part of inner layer 1, which has a width of 0.037 in. This is followed by inner layer 2, which is another plane layer made with 1 oz. copper and is 0.0014 in. thick. Another prepreg sublayer constituting two sheets that are 0.0091 in. thick forms part of inner layer 2. The final layer, the bottom layer, is also 0.0014 in. thick, and is a signal layer as well. Interconnects are soldered and placed on the top and bottom layers.
Cost of four layer PCB is higher than Double Sided PCB because of complexity of design and higher sensitivity. The better quality of signals, achieved by reducing distortion and propagation levels, is also a factor. Because of the higher levels of signal integrity and reduced interference levels, more manufacturers prefer four layer PCB.