PCB Copper Demand
The basic characteristics of printed circuit board depends on the performance of the substrate board, that means to improve the technical performance of PCB boards must improve the PCB performance first. In order to meet the needs of the PCB development, a variety of new materials is being gradually developed and put into use.
In recent years, the concentration of PCB market has shifted from computer to communication, including base stations, servers, mobile terminals, etc. Mobile communication devices have driven PCBs to higher density, thinner and higher functionality. PCB board technology is inseparable from the substrate material, which also involves the PCB substrate technical requirements.
High-density and thin-line are more frequently designed on latest PCB boards, especially in a HDI board. The definition of HDI under the IPC ten years ago was the line width/ line spacing (L/S) is 0.1mm/0.1mm and below, and now the industry basically conventional L/S is 60μm, and the advanced one is L/S 40 μm. Japan's 2013 version of the installation technology roadmap data for HDI board is 50μm as a conventional L/S, 35μm as an advanced L/S, and of 20μm as a trial L/S.
The traditional formation way of PCB circuit pattern is to use subtraction method after copper foil substrate photographic imaging. This method of making fine lines is limited to a minimum of about 30 μm, and a thin copper foil (9-12 μm) substrate is required. Due to the high price of thin copper foil CCL, and thin copper foil lamination defects, more factories produce 18μm copper foil and then take the production of thinning copper layer. This method requires many steps, difficult thickness control, high cost, thus it is better to use thin copper foil.