4
\$\begingroup\$

Basically, I'm wondering if the size of a via pad and drill has any effect on my circuits. For example, let's look at two vias:

enter image description here

One via has a smaller drill and more copper around the edges, while the second has a larger drill and therefore less copper around the edges. Both vias take up the same amount of space on the board.

Which type of via is generally preferred, and why? Is there a difference if I choose to fill the vias with solder?

\$\endgroup\$
  • 1
    \$\begingroup\$ What do you mean by "performance"? \$\endgroup\$ – Leon Heller Aug 17 '14 at 15:40
  • \$\begingroup\$ I'm just designing a board and wondering how I should set my via drill and pad sizes. Maybe having a too large/small pad or drill could affect how electricity travels through the via... \$\endgroup\$ – bubbles Aug 17 '14 at 16:34
  • \$\begingroup\$ @d.free Please consider accepting my answer, if it helped you. \$\endgroup\$ – Armandas Jan 9 '16 at 11:26
6
\$\begingroup\$

The copper around your drill hole is called an "annular ring". Manufacturers normally specify a minimum value for the annular ring, since drill registration is not perfect. If you have insufficient amount of copper around the hole, you may get breaks in the via, as illustrated below. enter image description here

When choosing the drill size, you consider factors like available board space and required current capacity. Larger diameter vias will carry more current, but I personally prefer to place many smaller vias instead of a few big ones.

I haven't heard of vias being filled with solder [EDIT: looks like this can be done post-production]. There is a technique, however, to fill vias with conductive epoxy and then plate them over. This is normally done when you need to have a via-in-pad for use with high-density BGAs. See here for more info:

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.