SLP is short for substrate-like PCB. It is the next generation of rigid pcb board, which can shorten the line width / line spacing from 40 / 50 μ m of HDI to 20 / 35 μ m, that is to say, the minimum line width / line spacing will be shortened from 40 μ m of HDI PCB to less than 30 μ m of SLP. At present, SLP can achieve 25 μ M. From the process point of view, SLP is closer to the semiconductor IC package derivatives, but it has not yet reached the specification of IC package derivatives, and its purpose is to carry various active and passive components, so it still belongs to the category of PCB. SLP board for smart phones can carry twice as many electronic components as HDI in the same area.
Reducing the feature size of PCB for mobile phone is to make smart phone thinner and more powerful. As more and more functions need to be added, as well as larger and larger screens, power consumption becomes the key point. In smart phones, batteries take up most of the space. With the decrease of feature size on the circuit board, more integration needs to be realized in a fixed area. From iPhone 5S, compared with the total area of smart phones, the proportion of PCB area of Apple iPhone gradually decreased. Until the latest iPhone X series, the area share has been reduced by 3%, but the function has been increased, and the battery capacity has been increased. At the same time, iPhone x not only uses SLP, but also stacks up two SLPs to further increase integration within a fixed area.It is estimated that by 2022, the global SLP market will reach 27.4 billion RMB, accounting for 26.6% of the output value of mobile phone PCB.