This instructable shows how to create well done PCB's using Ultraviolet light. It took us about 40 boards before we perfected our PCB, so we will share what worked and what didn't work. All the supplies can be bought from Fry's Electronics, Ace Hardware, Goodwill, Radio Shack, and Ebay . Our PCB tested the Atmel 208 pin PQFP Integrated Circuit (it may not look like it from the poor image quality but there were no shorts between all 208 pins!
The materials needed are as follows. PCB:
-Transparencies (MG chemicals brand http://www.mgchemicals.com/products/416t.html
-UV Presensitized Copper Clad Boards (MG chemicals brand http://www.mgchemicals.com/products/600.html
-Laser printer (Brother HL-2070N)
-200 UV LEDs (Bought from Ebay - Asia Engineer, seller giorgio11185. 5mm size, 3.4~3.8 forward voltage, forward current 20 mA, wavelength (nm) 395-400-405, view angle about 25 degrees.)
-200 470 ohm resistors (included with Asia Engineer LEDs bought on ebay. I used 12V for each LED).
-4 Breadboards for LEDs (http://www.radioshack.com/product/index.jsp?productId=2102843
-PCB Standoffs (http://www.radioshack.com/product/index.jsp?productId=2102848
-Chest/box to house LEDs (Bought at Goodwill. 20 inch length x 12 inch width x 11 inch height)
-Picture frame transparent plastic (Bought at Goodwill) Chemicals:
-Muriatic Acid (http://www.acehardwaresuperstore.com/transchem-muratic-acid-for-use-in-etching-concrete-p-5243.html
-Hydrogen Peroxide (http://www.walgreens.com/store/product.jsp?CATID=302248&navAction=jump&navCount=0&nug=VPD&skuid=sku1375525&id=prod1375535
-Photoresist Developer (MG chemicals brand http://www.mgchemicals.com/products/418.html
-Baking Soda (local grocery store. Use if any acid is spilled on your skin)
-Acetone (Ace Hardware) Tools:
-Soldering Iron (any soldering iron will do, I used http://www.amazon.com/Weller-WESD51-Digital-Soldering-Station/dp/B000ARU9PO/ref=sr_1_1?ie=UTF8&s=hi&qid=1246827601&sr=1-1
-Solder (We originally bought Lead free solder. This type of solder did not work. Instead we used Sn63/Pb37, 2.2% Flux, 23 gauge MG Chemical brand)
-26 and 16 gauge wire
-Gloves (bought at Ace Hardware)
-Goggles (bought at Ace Hardware)
-Power Supply (wall wart or benchtop power supply will do. Make sure your power supply can handle the current the LEDs consume. As you can see from my photo, my voltage was 11.9V and 3.47 Amps were consumed).
-Q-Tips (local grocery store)
-Buckets for chemicals (Ace Hardware)