Editing Printed circuit board (section)

=== Recent advances ===
Recent advances in [[3D printing]] have meant that there are several new techniques in PCB creation. 3D printed electronics (PEs) can be utilized to print items layer by layer and subsequently the item can be printed with a liquid ink that contains electronic functionalities.

HDI (High Density Interconnect) technology allows for a denser design on the PCB and thus potentially smaller PCBs with more traces and components in a given area. As a result, the paths between components can be shorter. HDIs use blind/buried vias, or a combination that includes microvias. With multi-layer HDI PCBs the interconnection of several vias stacked on top of each other (stacked vías, instead of one deep buried via) can be made stronger, thus enhancing reliability in all conditions. The most common applications for HDI technology are computer and mobile phone components as well as medical equipment and military communication equipment. A 4-layer HDI microvia PCB is equivalent in quality to an 8-layer through-hole PCB, so HDI technology can reduce costs. HDI PCBs are often made using build-up film such as ajinomoto build-up film, which is also used in the production of [[flip chip]] packages.<ref>{{cite book |chapter-url=https://ieeexplore.ieee.org/document/8546431 |title=2018 7th Electronic System-Integration Technology Conference (ESTC) |doi=10.1109/ESTC.2018.8546431 |s2cid=54214952 |chapter=High Density Interconnect Processes for Panel Level Packaging |date=2018 |last1=Ostmann |first1=Andreas |last2=Schein |first2=Friedrich-Leonhard |last3=Dietterle |first3=Michael |last4=Kunz |first4=Marc |last5=Lang |first5=Klaus-Dieter |pages=1–5 |isbn=978-1-5386-6814-6 }}</ref><ref>{{cite book |url=https://books.google.com/books?id=4DmIDQAAQBAJ&dq=build+up+film+substrate&pg=PA319 |isbn=978-3-319-45098-8 |title=Materials for Advanced Packaging |date=November 18, 2016 |publisher=Springer }}</ref> Some PCBs have optical waveguides, similar to optical fibers built on the PCB.<ref>{{cite web |url=https://www.laserfocusworld.com/optics/article/14040276/making-optical-printed-circuit-boards-on-an-industrial-scale |title=Advances in Optical Communications: Making optical printed circuit boards on an industrial scale |date=October 2019 }}</ref>