5
\$\begingroup\$

On a PC board is the first dielectric layer looking into the board from the top or the bottom layer of copper always prepreg or can it be a core? Here "can" would mean conventional. If not then why?

I asked this leaving work for the weekend. This week I asked the board house this question and they said generally prepreg is always used under the outer layers. I didnt ask why though. If no one will do it then the why doesnt really matter.

\$\endgroup\$

1 Answer 1

Reset to default
7
\$\begingroup\$

It can be done either way, but conventionally the surface layers are copper foil over prepreg.

Here are two different ways to do a 6-layer board:

6lyr

The one on the right is the standard stackup style of every board house I've used.

\$\endgroup\$
3
  • \$\begingroup\$ You can also do PPCPP as well - I've used that in one design. \$\endgroup\$
    – Tom Carpenter
    Commented Aug 20, 2016 at 0:49
  • \$\begingroup\$ You've done the left one before? Is the right one mainly better to control the board thickness? Since prepreg is pressed the thickness can be controlled right? \$\endgroup\$
    – Jason
    Commented Aug 20, 2016 at 13:29
  • \$\begingroup\$ @Jason No, I haven't made the left one. After I wrote this answer, I asked a related question about why these would be done. Please take a look! \$\endgroup\$
    – bitsmack
    Commented Aug 22, 2016 at 21:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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