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

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

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

1917509919.1291317844606551.JavaMail.jive@flmspu-csapp-02.premierfarnell.com...

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

Hello Magnus,

As long as your manufacturer can do it, everything should be ok. I suggest

you give them a call to make sure they understand your needs.

Then it's all about commenting your drawings (text and arrow) to show which

vias needs filling...

Usually the board outline is drawn by a fine line on the layer dimension

(20). Just draw another set of lines to define the inner rounting of your

cutout. Again, comment it.

You only need one cutout board on your stack.

The best place to comment is directly on the target layer. Write cutout on

the dimension layer. The manufacturer will remove the text before

processing.

Good luck,

Jerome

On 10/05/2011 03:56 PM, Magnus Adelmor wrote:

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?

I believe what you're looking for is called a "blind via", which is a

via that begins on one surface of the board, but does not penetrate

through to the other side - it stops on an inner layer.

Blind vias can be setup in eagle's DRC dialog box.  Since I have never

used blind vias, I can not purport to know how to set them up.  The

DRC->Layers tab provides an example with which you can start.

Enjoy,

    - Chuck

Chuck Huber <chuck.huber@dukepro.com> wrote:

On 10/05/2011 03:56 PM, Magnus Adelmor wrote:

>> 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?

 

I believe what you're looking for is called a "blind via", which is a

via that begins on one surface of the board, but does not penetrate

through to the other side - it stops on an inner layer.

 

Blind vias can be setup in eagle's DRC dialog box.  Since I have never

used blind vias, I can not purport to know how to set them up.  The

DRC->Layers tab provides an example with which you can start.

I believe he is talking about this technique:

http://blog.screamingcircuits.com/2010/06/how-to-fill-a-via.html

Eagle does not support that but the manufacturer should be able to do it

manually.