HOW TO PRODUCE PCB
Instructions of making PCB by
using Negative Film Resist
By: FYP @ PCB Fabrication Lab
Telecommunication Engineering Department.
FKEKK, UTeM
STEP 1 : PRINT THE ARTWORK
• FINALIZE THE CIRCUIT TO BE PRINTOUT. PRINT ONLY THE TOP
@BOTTOM LAYER WITHOUT TOP@BOTTOM SILK MASK
• NAME SHOULD BE MIRRORED
• PRINT THE ARTWORK ON THE TRASPERANCY SHEET
• THE ARTWORT SHOULD BE PRINT IN THE NEGATIVE IMAGE
(WHITE CIRCUIT WITH BLACK BACKGROUND)
• IT IS IMPORTANT TO PRINT IN HIGH RESOLUTION
OTHERWISE PRINT THE ARTWORK IN TWO COPIES AND
COMPLIES TOGETHER TO GET THE BLACK AREA IN HIGH
BLACK RESOLUTION.
• PRINTING MAY BE FROM LASERJET OR BUBBLE JET. BUT THE
BEST IS BY USING A LASER JET PRINTER.
PRINT THE NEGATIVE ARTWORK
STEP 2 : CLEAN THE BOARD
• Choose the copper board and clean with very
fine grade of sand paper. For best results, clean
the board using fine steel wool or similar
abrasive pad. After cleans rinse the copper
board with water. This will remove dirt, oils,
and other contamination on the top of the
copper board.
• The board must be absolutely clean and dry
prior to applying film. (Note: After rinse, the
board should be dried quickly to avoid
oxidization.)
CLEANING THE SURFACE OF THE BOARD
Copper board before cleaning with
fine steel wool/sand paper
Copper board after clean with fine
steel wool/sand paper
Step 2: CUT THE DRY FILM FOTORESIST
•Work in a safe light environment when
handling the film – any exposure to UV light
will expose the film. Safe light refers to any
incandescent bulb less than 40 watts.
Step 2: CUT THE DRY FILM FOTORESIST
• Sharp scissors @ knife work best for cutting
this film. The amount of film required
depends on the size of the board being
laminated. A 1 cm border should be left on all
sides of the board due to shrinkage from heat.
(See diagram 2b)
Step 2: CUT THE DRY FILM FOTORESIST
• For double sided boards, cut the film big
enough (one piece) to sandwich the board in
the middle. (See diagram 3c) For a doublesided board, you will only have the 1 cm
border on 3 sides. No border is required for
the side where the film meets the board.
Diagram 2b
Diagram 3c
STEP 3 : REMOVE THE PROTECTIVE
LAYER AND APPLY THE FILM
• First peel off the protective coating (on the
side with the sticker - the soft hazzy side).
Apply the film face down with the side that
just had the film removed. Fold back the film
on the side that will be fed into the laminator.
(See diagram 3b) It is important that the film
is wrinkle free.
For a double-sided board, no folding is
required as the board is already sandwiched
between the film. (See diagram 3c)
Diagram 3b
Diagram 3c
STEP 4 : LAMINATE THE DRY FILM
FOTORESIST
• Turn on the laminator. Set the temp to 120C.
Wait until the laminator ‘ready’ indicator is
on. Feed the board with the film side facing up
into the laminator. Feed the side of the board
with the excess border folded back.
• Once the board finishes laminating, put it
through the laminator for a second time
immediately after the first run (if required).
The process is the same for the double-sided
board.
LAMINATING THE DRY FILM
FOTORESIST
LAMINATING THE DRY FILM
FOTORESIST ON THE TOP OF THE
COPPER SURFACE
LAMINATED DRY FILM RESISIT ON THE
COPPER BOARD
TOP PROTECTIVE LAYER
DRY FILM RESIST
COPPER LAYER
STEP 5 : EXPOSING THE BOARD
• EXPOSING THE DRY FILM RESIST PROCESS IS TO TRANSFER THE
ARTWORK CIRCUIT AT THE TOP OF THE BOARD.
• THIS PROCESS REQUIRES UV LIGHT WITH 375nm WAVELENGTH @ UV
EXPOSING UNIT
• THE PRINTOUT WILL BE ACT AS A MASK.
• THE RESIST AREA WHICH THE UV LIGHT GO THRU WILL BECAME DARKER
AND VICE VERSE.
• POSITION THE ARTWORK IN CONTACT WITH THE RESIST SIDE OF THE
COPPER BOARD AND PLACE DOWN BOTH IN THE UV EXPOSURE UNIT.
• HAVING CLOSE THE LID , SET THE TIME TO 30 SEC OF THE EXPOSING TIME
FOR THE DRY FILM.
• THE ARTWORK CAN BE SEEN LIGHTLY AT THE TOP OF THE BOARD AFTER
EXPOSING PROCESS.
IMPORTANT TO CONCERN!
• PIN 1 OF THE IC (INTEGRATED CIRCUIT) AT THE
RIGHT TOP SIDE
• WIPE THE TOP GLASS WITH DRY CLOTH TO MAKE
SURE THEY ARE CLEAN FROM DUST.
• CLOSE THE UV EXPOSING UNIT LID SECURELY
BEFORE BEGINNING THE EXPOSURE.
• DO NOT OPEN THE LID DURING THE EXPOSURING
PROCESS. DIRECT UV LIGHT EXPOSE TO YOUR EYE
WILL SLIGHTLY DAMAGE THE EYE CORNEA
COPPER BOARD DURING UV EXPOSE
PROCESS
CIRCUIT PRINTOUT (MASK)
TOP PROTECTIVE LAYER
DRY FILM RESIST
COPPER LAYER
COPPER BOARD AFTER UV EXPOSE
PROCESS COMPLETE
TOP PROTECTIVE LAYER
DRY FILM RESIST
COPPER LAYER
STEP 6 : DEVELOPING THE IMAGE
• AFTER THE BOARD HAS BEEN EXPOSED, PEEL OFF THE PROTECTIVE
LAYER ON THE TOP OF THE RESIST BEFORE GOES TO DEVELOPING
PROCESS.
• DRY FILM RESIST DEVELOPER ACT AS SOLVENT AGENT TO DISSOLVES THE
UNEXPOSED PART OF THE DRY FILM RESISIT.
• THE PART WHICH THE ULTRAVIOLET RAYS LASHED DOSEN’T DISSOLVES IN
THE DEVELOPER.
• THE PART WHICH THE ULTRAVIOLET RAYS DIDN'T LASH DISSOLVE IN THE
DEVELOPER AND THE COPPER FOIL APPEARS. THE EXPOSED RESIST LEFT
AS THE MASK PATTERN ON THE TOP OF THE COPPER BOARD.
• THIS MASK PATTERN DOESN'T DISSOLVE IN THE ETCHANT.
• THE BOARD SHOULD BE FULLY DEVELOPED IN 120 SECONDS.
• THE DEVELOP TIME, ARE CHANGES WITH THE SIZE OF THE PRINTED
BOARD, THE AREA WHICH DISSOLVES THE RESIST.
• RINSE WITH CLEAN WATER TO REMOVES REMAINING DRY FILM RESIST.
STEP 6 : DEVELOPING PROCESS
• PLACE THE BOARD TO BE DEVELOPED IN PA TANK BOARD
HOLDER AND IMMERSE IN THE DEVELOPING TANK
• WHEN DEVELOPING, REMOVE AND WASH AFTER 15—30
SECONDS. IF THE BOARD NEEDS A LITTLE MORE
DEVELOPMENT, THEN IMMERSE INTO THE DEVELOPER FOR A
FEW MORE SECONDS AND THEN WASH IMMEDIATELY
AGAIN.
• IT IS VERY IMPORTANT TO ENSURE THE BOARD IS NOT OVERDEVELOPED. THE DEVELOPED IMAGE CAN LOOK GOOD, BUT
OVER-DEVELOPING CAN CAUSE A REDUCTION IN THE
THICKNESS OF THE RESIST, WHICH COULD THEN BREAK
DOWN AT THE ETCHING STAGE
DEVELOPING PROCESS
RESIST COPPER BOARD AFTER
DEELOPING AND CLEAN WASH
EXPOSED DRY FILM RESIST
COPPER LAYER
DEVELOPING
PROCESS
EQUIPMENT
STEP 7 : ETCHING THE BOARD
• FERRIC CHLORIDE IS THE MOST WIDELY USED ETCHANT, BECAUSE IT IS
CHEAP, HAS LONG TANK LIFE AND ETCHES QUICKLY AND EFFICIENTLY. ITS
ONE DRAWBACK IS THAT IT IS MESSY AND STAINS, HOWEVER IF YOU
WEAR PROTECTIVE CLOTHING (RUBBER GLOVES) LAB JACKET AND
ENSURE ANY SPILLAGE IS WIPED AWAY IMMEDIATELY WITH A DAMP
CLOTH.
• JUST PLACE THE BOARD THROUGH THE ETCHING CONVEYORISED TANK.
PLACE AT THE TOP OF THE ROLLER.
• THE ETCHING TEMPERATURE IS SET TO 45C AND THE ETCHING PROCESS
SHOULD TAKE APPROXIMATELY 5 MINUTES.
• FOR VERY FINE DETAIL THE BOARD SHOULD BE RETURN TROUGH THE
ROLLER FOR THE ETCHING CYCLE. MAKE SURE THAT THE BOARD ALWAYS
WASH THRU CLEAN WATER BY PRESSING THE WASH BUTTON .
• WHEN ETCHING IS COMPLETETED, SPRAY WASH TO CLEAN THE FERRIC
CHLORIDE.
STEP 7 : ETCHING THE BOARD
ETCHING PROCESS
BOARD AFTER COMPLETE ETCHING
DRY FILM RESIST
COPPER
AFTER ETCHING BOARD
STEP 8 : STRIPPING THE DRY FILM
RESIST LAYER
• THE PCB WILL NOW CONSISIT OF AN ETCHED CIRCUIT STILL COVERED IN
THE DRY FILM PHOTORESIST LAYER. THIS LAYER CAN BE REMOVED WITH
THE DRY FILM RESIST STRIP APPLICATOR.
• PUT THE BOARD INSIDE THE BOARD HOLDER IN THE WASH TANK
CONTAINING THE RESIST STRIPPER. SET THE TEMP TO 45C-50C.
• AS BEFORE THE LID/BOARD HOLDER IS RAISED AT ANY TIME TO
EXAMINE THE BOARD.
• THE PHOTORESIST SHOULD BE STRIPPED OFF IN APPROXIMATELY 3-5
MINUTES.
• ONCE THE PHOTORESIST LAYER HAS BEEN STRIPPED FROM THE CIRCUIT
THE BOARD ARE THEN RINSE WITH CLEAN WATER.
• DRY THE BOARD WITH CLEAN TISSUE. THE BOARD NOW CAN BE DRILL
FOR COMPONENT PLACING.
STEP 9 : DRILLING HOLE FOR
COMPONENT
• PLEASE PUT ON THE SAFETY GLASS BEFORE YOU STARTED
DRILLING HOLE IN THE BOARD.
• CHECK THE CONDITION OF THE DRILL STATION AND THE
DRILL BITS. MAKE SURE THEY ARE NOT BROKEN. DO NOT
USE BROKEN BITS FOR DRILL HOLE.
• DON’T PUT YOUR HAND AT THE DRILL BITS WHEN IT’S IN
THE MOTION.
• PLEASE TIDY UP YOUR DRILL STATION AFTER YOUR FINISH
DRILL THE HOLES
• SWITCH OFF THE DRILL STATION AFTER YOU ARE FINISH
DRILLING.
• THE BOARD NOW CAN BE PREPARED FOR COMPONENT
SOLDERING.
THANK YOU