Homebrew PCBs

----- Original Message ----- 
From: "Andrew" <andrewm1973@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, August 17, 2007 10:56 PM
Subject: [Homebrew_PCBs] Re: 0.5mm pitch breakout board?


>
> I agree with DJ - Do a panel of them to make sure you get a good one
> if you are not always doing stuff that small.
>
> I have just done a 0.45mm QFN package (ATMega48) and the resist came
> out good.  The etch is what I had a problem with.  I panelised 15
> boards to make sure I got a good one.
>
> Some tracks (6-8 thou) almost got etched completly away on one side
> of the panel before the other side was clear of copper.
>
> I guess it is dinfitly a case of some people have got bubble etchers
> that work well and mine is crap :D
>
> I think I am going to keep a tub of Ferric Chloride around just to do
> these fine ones and float etch them till I get a spray happening.

I've done one or two single-sided QFN boards for accelerometers, I find it 
best to make one at a time.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND and FT-857D transceivers
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller