The need to have multiple functions in the same electronic device has made it essential to incorporate “more electronics” into printed circuit boards.
This trend has sped up miniaturisation of electronic components and promoted the development of multi-layer PCBs.
A greater quantity of copper layers means more interconnections are possible. Together with more complex electronics, this translates to additional functions.
Multi-layer PCBs accommodate a wide variety of needs which is why they are the most popular, along with double-sided printed circuit boards.