Vias for Dummies
In simple terms, a circuit board is but a composition of things designed to be connected and not. The number of layers and number of connections make no real difference as the geometry shapes the landscape. The via is but one tool that helps in building the wonder that is a printed circuit board, and in this column, we’ll discuss the via in relation to the variety of types available for use as well as some of the testing that can be performed on them to ensure their reliability.
A small—sometimes very small—yet important part of the circuit board landscape, the via, by definition, is simply the means by which layers of the board can be interconnected. What differentiates the via from a plated through-hole is simply the fact that nothing (i.e., a component lead) will get inserted and possibly soldered into the structure. Further, vias don’t have to extend from one side of the board to the other, although they certainly can as a through via.
Blind vias start at the surface on one side of the board but don’t extend to the other side, while buried vias (Figure 1) are completely encapsulated within the board with no end extending to either surface of the board.
To read this entire article, which appeared in the November 2016 issue of The PCB Magazine, click here.