INSTRUCTION FOR THE USE OF THE PCB LITHOGRAPHY LABORATORY
Set on the “ON” position the switches on the general electrical panel:
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Turn on the extractor fan above the etching machine with the “INT4” switch located under the little window, on the right side, of the DEVELOPMENT-ETCHING workbench.
Turn on the ETCHING MACHINE. The switch “INT3” is on the DEVELOPMENT-ETCHING workbench.
Make sure the machine is turned on.
Turn on the extractor fan of the SAFETY CABINET.
The switch “INT1” is on the left side of the safety cabinet.
Take the PRINTED CIRCUITS COLLECTOR on the right side of the CONTACT PRINTER. Fill in the form (1 page) with the required data. Take note of the last user’s times for the development with CAUSTIC SODA and etching with FERRIC CHLORIDE (this is useful to get an idea of the time required to realize your PCB).
1 EXPOSURE TO THE CONTACT PRINTER
Turn on the CONTACT PRINTER with the red light switch “POWER”. Remove the adhesive protection on the Presensitized Board (1 adhesive for SINGLE-SIDED PCB, 2 adhesives for DOUBLE-SIDED PCB). Extract and open the contact printer compartment. Place the tracing paper on the Presensitized Board (for single-side boards place the tracing paper on the side without the adhesive protection, while for double-side boards place the Presensitized Board between the two tracing papers). Close the contact printer compartment. Press the red light switch “VACUUM” to create the vacuum that will make the tracing paper adhere to the Presensitized Board. If the Board and the tracing paper adheres perfectly you can reinsert the compartment under the contact printer. Leave the vacuum pump run and be sure that the analog vacuometer doesn’t exceed 40cmHg (during all the exposure process). Select 1 or 2 lamps with the red light switch “LAMPS” (1 lamp for single-side boards and 2 lamps for double-side boards). Turn on the UV LAMPS with the switch “ST” located in the lower right corner of the display (the default exposure time is 180 seconds but it is possible to turn off the lamps at any time by pressing the switch “ST”). After 180 seconds be sure that the lamps are turned off. Then, extract the contact printer compartment. Turn off the vacuum pump with the switch “VACUUM”. Open the tray and remove the Presensitized Board and the tracing paper. Finally, turn off the contact printer.
2 DEVELOPMENT WITH CAUSTIC SODA
Place the Presensitized Board into TRAY 4. Wear the lab coat. Wear the protection gloves and glasses that are located in TRAY 1 (Please note: In the laboratory, protection of eyes and hands is mandatory). Place the extractor fan above TRAY 4. Pour the caustic soda (located in the safety cabinet-door, BASES section) on the Presensitized Board. The time required for the development will be a little longer compared to the one measured by the user that made the last PCB (see the COLLECTOR). When the tracks are well defined the development phase is over. Keep the extractor fan above the etching machine.
3 CLEANING WITH WATER
Place TRAY 4 near the little sink located on the DEVELOPMENT-ETCHING workbench. Remove the board from TRAY 4, put it into the little sink and rinse with water. Leave the board in the little sink. Put the caustic soda back in the bottle located in the safety cabinet. Put TRAY 4 in the big sink. Wash and dry the tray with paper towel (TRAY 2). Put TRAY 4 back in its place. Dry the board (which was left dripping) with the ELECTRIC TOWEL (in this way we do not dilute the FERRIC CHLORIDE present in the ETCHING MACHINE).
4 ETCHING WITH FERRIC CHLORIDE
Having turned on before both the EXTRACTOR FAN and the ETCHING MACHINE, the FERRIC CHLORIDE is at the temperature of about 30°C. Take one of the clamps from TRAY 5 or use a PRINTED CIRCUITS HOLDER (TRAY 6) if you have a standard size board. Put the Presensitized Board in the ETCHING MACHINE. The time required for etching will be a bit longer compared to the one measured by the last user. Put the circuit in TRAY 7 when the etching phase is over. Clean immediately with paper towel (TRAY 2) if some ferric chloride spilled on the etching machine or on the workbench.
Turn off the ETCHING MACHINE (INT3) and the EXTRACTOR FAN (INT4).
5 CLEANING WITH WATER AND ALCOHOL
Place TRAY 7 near the LITTLE SINK on the DEVELOPMENT-ETCHING workbench. Remove the board form TRAY 7, put it into the little sink and rinse with water. Leave the BOARD in the LITTLE SINK. Put TRAY 7 in the BIG SINK and clean and dry it with paper towel (TRAY 2). Put TRAY 7 back in its place. Take the board from the little sink, put it in TRAY 7 and wash it with alcohol (lowest shelf of the safety cabinet’s door, BASES section).
Remove all the photoresist by rubbing vigorously and dry with paper towel (it is possible to use steel wool to make the soldering process easier). Wash and dry TRAY 7.
Take off gloves and glasses.
Take note on your own form about the development and etching times. Check if all the machines are turned off and everything is clean and in order.
Also check if the form in the PRINTED CIRCUITS BINDER for making the printed circuit board is filled out.
Turn off the extractor fan safety cabinet (the switch “INT1” is on the left side of the DEVELOPMENT-ETCHING workbench).
Take off the lab coat.
Put on the “OFF” position the switches
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If you have done all the above steps the next user will find all cleaned and in order and this will make him very happy. Thank you.
6 TRIMMING WITH THE CUTTER
If you want to trim the PCB, it is possible to use the CUTTER located in the
Electronic Teaching Laboratory - Classroom B3.
7 PCB DRILLING
The drill is located in the Electronic Teaching Laboratory- Room B3.
Wear the protective glasses. Drill the PCB. Take off the protective glasses
THE END