The technological transformation and market trend in the PCB industry

As an important electronic connector, PCB is almost widely applied in all the electronics, which is considered as “the mother of the electronics”. Therefore, technological transformation and market research of the PCB industry has become the focus of many insiders.

There are two obvious trends in the present electronic products: one is being light and short while the other is being high-speed and high-frequency, which drives the downstream PCB to develop into a high-density, high-concentration, encapsulating, sophisticated and multi-layer ones and contributes to a rising demand for high-layer plates and HDI. Being short in length of wiring and with low circuit impedance, high-layer plates, with the advantages of work with high frequency, stable performance, however, have more complicated functions, which is an unavoidable trend for the electronics technology to develop into a high –frequency, high-speed, multi-function, high-capacity ones. Besides, the further application of large – scale integrated circuit will further drive the PCB to step into a stage of high precision and high layers. 

Currently, PCB lower than 8 layers are mainly applied in electronics, such as, home appliances, PC, desktop computer, while the high-end applications, such as, multifunctional servers with multi channels, aerospace, usually requires that PCB should have at least layers. Taking server as an example, the PCB plates applied in the single-channel and double-channel server range from 4 to 8 layers while the PCB plates applied in the motherboard of high-end server, such as, four channels or eight channels should have over 16 layers and those in backboard should have more than 20 layers.

The density of HDI wiring are obviously advantageous than the ordinary multi-layer plates, which has become the main choice for the mainstream mother board of smartphones at present. As the functions of the smartphone is becoming more and more complicated while its size of developing into smaller and lighter, the room available for mother board is getting less and less and the more boards are required to install more components and parts. Therefore, the ordinary multi-layer plate can no longer meet the needs.

HDI plates employ lamination method to produce the plate. Taking the ordinary multi-layer plate as the core one to accumulate layers, coupled with drilling and the procession of metallization inside the holes, circuits linking the layers can be connected more firmly. Compared with the ordinary multi-layer plate with through holes alone, HDI can reduce the number of through holes by setting the blind holes and buried holes in a more accurate way, which can greatly save the wiring area for PCB and increase the density of the electronics significantly. Therefore, they rapidly take the place of multi-layer plate in smartphones.

The distinctions between different HDI techniques lie in the added storey in that the more storeys there are, the more difficult the technique will be. Based on the number of storey, HDI can be classified into one- storey HDI, two- storey HDI, high- storey HDI, etc., which are marked by C+N+C, among which “C” stands for the number of storeys, “C” stands for the times for storey adding, namely the number of HID storeys. High-storey HDI requires higher density and more times of lamination as well, coupled with such technical difficulties in counterpointing, punching, copper plating, which all sets higher requirements for the manufacturers in terms of technology craft and processing ability. 

In recent years, arbitrary storey HDIs which are widely applied in high-end smartphones are usually the one with the highest storey, which requires that neighboring stories are connected with blind holes, which can save half of the volume compared with the ordinary HDI, so as to spare more space to hold parts such as batteries.