Filled vias

"Magnus Adelmor"  a écrit dans le message de groupe de discussion :

1819182079.8511317738586354.JavaMail.jive@flmspu-csapp-02.premierfarnell.com...

HI,

I am new to this and am only using eagle to design boards/substrates for

microeletronic packages. I would prefer to do it in 3D cad, but PCB

suppliers prefere to have gerber file...

1. How do I create a plugged/filled vias with a pad on both top and bottom?

2. Can I have different size and shape pads on top and bottom when creating

a via?

3. How do I create a substrate with a cavity?

Hello Magnus,

Conventional PCBs are pretty different from microelectronics technologies. I

am not aware of any manufacturer that offer plugged vias nor cavity, so you

will have to trick them.

For the cavity you could use a stack of three thin PCB. The issue will be to

interconnect them. Depending on the number of connection, you could use

through hole conenctors, or some bondings.

As you probably have a limited number of traces you could just draw them

with rectangles/lines on top & bottom layers directly, without using the

traces. This way you have perfect control on spacing and width.

Avoid Eagle vias and draw your pads with any shape. Just add a drill in the

middle.

Do you have a good reason for a filled vias ? Maybe you can use very narrow

drills instead ? Vias typically have similar thickness as the copper layers.

Jerome

"Magnus Adelmor"  a écrit dans le message de groupe de discussion :

1819182079.8511317738586354.JavaMail.jive@flmspu-csapp-02.premierfarnell.com...

HI,

I am new to this and am only using eagle to design boards/substrates for

microeletronic packages. I would prefer to do it in 3D cad, but PCB

suppliers prefere to have gerber file...

1. How do I create a plugged/filled vias with a pad on both top and bottom?

2. Can I have different size and shape pads on top and bottom when creating

a via?

3. How do I create a substrate with a cavity?

Hello Magnus,

Conventional PCBs are pretty different from microelectronics technologies. I

am not aware of any manufacturer that offer plugged vias nor cavity, so you

will have to trick them.

For the cavity you could use a stack of three thin PCB. The issue will be to

interconnect them. Depending on the number of connection, you could use

through hole conenctors, or some bondings.

As you probably have a limited number of traces you could just draw them

with rectangles/lines on top & bottom layers directly, without using the

traces. This way you have perfect control on spacing and width.

Avoid Eagle vias and draw your pads with any shape. Just add a drill in the

middle.

Do you have a good reason for a filled vias ? Maybe you can use very narrow

drills instead ? Vias typically have similar thickness as the copper layers.

Jerome

Hi Jerome,

Thanks for your help.

We have a substrate manufacturer who does plugged vias. We will perform ball bondning on the pad, therefore we need the via filled.

Your description on how to make cavities is what we would like to do. But how do I make make a cut-out in the top pcb in order to create a cavity? Can I design these three pcb's as a stacked design and only create a cut out in one of the pcb's?

If I do not use Eagle's via, how do I tell the manufacturer that the small hole should be a via, a filled via? Besides being new to Eagle, I have a lack of understanding regarding gerber files and drill files...

Mags