In 1997, the first HDI multilayer printed circuit boards were developed for mass production for the mobile phone market, which was in its infancy. The multilayer printed circuit boards made it possible to embed complex circuits within a small space. The high degree of miniaturisation, the short and rapid signal paths and the resulting reduction in energy consumption were exactly what mobile phone manufacturers needed at the time.
To achieve this, laser systems were used for the first time to create precise holes in the printed circuit board. This established the new practice of working with sequential build-up layers layers (SBU), which are pressed layer by layer into a compact circuit board. Ever since then, HDI printed circuit boards have been indispensable in the electronics industry ever since.