homemade multilayer PCB?

Just wondering if anyone has made their own multilayer PCBs and how
they did it. Can you buy thin blanks and laminate them somehow?

 

Yes, I make gerbers and send them to a PCB shop.
The "somehow" includes high temperatures and pressures for hours, and
is also an experience-based endeavor, there will be a lot of scrap at
first.

 

I haven't done it but I have thought about it.

For the most part it's just stacked individual pieces. You could just glue
several single layer pieces together(would tend to be thick though).

I thought also about laminating my own bu I imagine this might be more of a
challenge. would need a decent press and decent adhesive.

The only real challenge IMO would be dealing with the holes/vias. (except
for simple designs) Although this isn't a real technical challenge but would
be time consuming and tedius.

When you start to think about it the time/cost/headaches involved starts
approaching that of getting it done professionally. Of course if you have
the time/money/space and will make more than a handfull it could be
worthwhile.

Remember, if your etching it you would also have to add the photoresist.

If you just need double sided and one will be a ground plane without traces
then I imagine you can just drill holes and use some wire to form the vias.
This wouldn't be very difficult at all.

Another method, if you only have single sided, would be to etch on both
sides on the one side but cut the board and glue them together then add the
wire vias. (would be twice as thick of course)

 

Man, laylow.. I am really bad at doing things myself I should let
someone else do. It's part of my character flaw package. I
understand the "do it yourself" thing. But manufacturing MULTI-LAYER
boards are really...hmmm, let's say they are FAR more work than they
are worth, especially because of the incredibly savage market out
there for PCBs. You really need to get the design into a single layer
with wire vias, or even two layer glued with wire vias to do it
yourself... Good luck.

 

Not a technical challenge? How do you propose to make connections to inner
layers of a multilayer PCB?
--

 

Um, think about it and maybe it won't be so difficult? (how do you think
they do it in the first place? magic?)

You first drill all the holes.

You do layer 1 and layer 2 this forms a new layer. Then treat that as a
single layer and do the same as the first step with layer 3. Do this until
you run out of layers. There are no interdepence between more than two
layers unless you have a via that is connected to several layers. This is a
little more tricky but not by much.

 

Not necessarily. I very much prefer 1/32" (0.8 mm) stock for "regular"
single-sided home-brew boards. Easy to cut to size with scissors, easy
to drill, rigid/strong enough for small projects. A double-sided board
would just use a pair of these glued together and you'd end up with one
just a bit thicker than the standard 1/16" PCB thickness.

 

Wonderful. Now explain how you get the copper inside the drill hole,
you know, to connect all these inner layers...

 

Um, if you were paying attention... or at least didn't think you knew it all
then you might get it.

Did you think you can use copper wire? huh? wouldn't that work? You do
realize that a via is the same thing as a TH? Have you ever used a lead of a
TH component to connect two sides together?

Note your so called inner layers are not inner layers until you have added a
layer. You built up the layers one at a time like any reasonably intelligent
person would do. Maybe you guys should read up on how they actually
manufacture multi-layer pcb's because I'm relativelys ure they don't start
out with all the layers unetched and sandwhiched together then use some type
of magic to get the holes and etching through.

Man... the intelligence of people supprises me every day... more so is the
arrogance.

 

Forget it. Not a practical prayer in hell.....

 

And how, pray tell, would you now glue all this mess together without
shorts? Huh? Would that work?

How would you connect the inner layers this way? You'd only connect
the outer layers this way.

They use chemistry and drills. They etch the laminations one at a
time. Then they drill the whole mess. Then they use chemical etch to
de-smear the holes.
Then they plate the holes. It connects all the layers at the same
time.

You say "relativelys ure" about stuff you have no clue about. Who's
arrogant here?

 

Of course it isn't. You're assuming the holes are already plated. Try
it and let me know how it works. So the idea is you need multiple
layers because your 1mm holes eat up so much space? Absurd.

Take a look at the temperature needed for bonding boards. Let me know
the coefficient of expansion of solder vs. fr-4.

I agree with 50% of that. Guess which 50%.

 

Eh, won't stop some people in here. There are still people who want to
convert laptop screens into a stand-alone monitor!!!!

 

Ok, whatever... I've never tried explaining calculus to a rock but I get the
feeling it would be similar to explaining this to you... except the rock
isn't an arrogant fool.

 

Wow, a graduate of the Phil Allison School of Internet Asshattery,
summa cum laude!
Look, you're not making sense. You don't know what you're talking
about, and I bet you never even try anything you talk about.
You change subjects every other day.

Try it. Take pictures. Put a video on Youtube. Show me how it's done.

I'll wait, I'm patient. I'm even generous; do you need a camera, or
materials?

 

If I remember rightly, getting the copper inside the via's after drilling
involves
electroless plating to get a thin conducting layer of something - it might
be
palladium - over everything, which you them plate up with copper until
you've got your one ounce per square foot, then you put a layer of
photoresist on both sides of the board and etch off the coper that you don't
need.

I've never done it, and I wouldn't dream of doing it - I've got a Ph.D. in
chemistry and I can imagine how may ways there are of getting it wrong -
but somebody felt the need to tell me all about it a long time ago when I
was bitching about the price we were having to pay for a multilayer board.

We got the baord eventually, and I've been a fan of buried ground planes
ever since.

 

Well, I don't know why we have to insult each other. It makes usenet
a rather unpleasant place considering that it's already inundated with
meaningless spam and dreadful trolls.

Anyway, I am just a hobbyist. I don't get paid to design circuits. I
am not likely to spend $50 to have a board made for something that
only I will play with. Especially knowing that the board might not
work exactly like I want it to the first time. In other words, with
regards to hobbies, I have more time than money.

Making a multilayer pcb seemed like a fairly do-able project. I just
expected that others would have perfected a diy method by now. The
only reason I would need a third layer is for something that looked
better than a mess of jumper wires. I thought that maybe someone
might have made a special conformal coating that doubled as a heat
sensitive bonding agent or maybe a product that acted like a light
layer of some flux like adhesive. Maybe I shouldn't have said
laminate. It seems like it would be fairly easy to stack up to four
layers by soldering pins to the middle layers before sandwiching them
together. The boards wouldn't even necessarily need to touch.

I put more stock in experience than conjecture so I am intersted in
hearing about what people have tried. I also realize that many things
are easier said than done but the whole point of asking in the first
place was to try to reduce the learning curve.

Thanks for all your input.

 

Wow. When the picture first started loading I thought it was a joke,
but sure enough, there's a perf board under there.

 

My friend, go to a hobby store that specializes in stained glass. You
will a selection of adhesive copper foils.

All in all, I think you should stick to 2 layer technologies. Develop
skills to find ways to route everything in 2 layers.

Instead of building a monster PCB, find different chips that can help
you reduce parts count or allow better routing.

Don't take address/data bus signal names as gospel, mix and match to
ease layout.

Get familiar with a PCB package.

I've made many personal projects (back when I cared to do such
things), and I always found a way to make planes and connect most
signals with only 2 layers. Use resistors (1206 lets you route a trace
between pads, through-hole 0 ohm resistors are great too).

Adding layers to a PCB requires pressing, heat and chemical processes
to plate the barrel of the via. It's the only way I know how to
connect reliably to inner layers that doesn't require a monk. It's
just not easy to do.

The fact that you need to drill the via automatically implies that the
inner layer copper is flush with the hole. It's always gonna be
difficult.

And even if you could magically plate via barrels, you still need to
laminate two boards together, with all the registration and adhesive
issues that go with it.

Find a way to use on-line PCB shops like Alberta Printed Circuits and
you can be prototyping the next day.

It's like programming, do you compile your own code or do you use some
sort of software to do it for you?

 

I made a "graphics adapter" rats-nest for a 6502 with a ram bank
consisting, IIRC, of 16 2114 RAMS all piggybacked together.