PCB Etching Methods: A Step-by-Step Guide (PDF)

METHODS 6.53 OF PCB ETCHING CT 9 Q3 OBJECTIVE Determine Acceptable Methods in transferring PCB layout to copper-cladded board 7/1/20XX Pitch deck title 2 WHAT ARE THESE? FeCl3 CuCl2 HCl H2O2 H2O 7/1/20XX Pitch deck title 3 ACIDIC ALKAL...

METHODS 6.53 OF PCB ETCHING CT 9 Q3 OBJECTIVE Determine Acceptable Methods in transferring PCB layout to copper-cladded board 7/1/20XX Pitch deck title 2 WHAT ARE THESE? FeCl3 CuCl2 HCl H2O2 H2O 7/1/20XX Pitch deck title 3 ACIDIC ALKALINE FeCl3 HCl CuCl2 H2O2 H2O 7/1/20XX Pitch deck title 4  PCB ETCHING a process of removal of unwanted copper (Cu) from the circuit board non-circuit copper is removed from the board as per the PCB design 7/1/20XX Pitch deck title 5  PCB ETCHING METHODS TONER TRANSFER w/ HEAT ACIDIC ETCHING ALKALINE ETCHING TONER TRANSFER w/o HEAT 7/1/20XX Pitch deck title 6  PCB MANUFACTURING HOUSES VS MAKING PCB AT HOME good idea if you are developing commercial products is a good idea if your design is simple (usually a single layered board) 7/1/20XX Pitch deck title 7  TONER TRANSFER METHOD 7/1/20XX Pitch deck title 8  TONER TRANSFER METHOD MATERIALS WITH HEAT WITHOUT HEAT PRINTER (LASER) PRINTER (LASER) HEAT TRANSFER MAGAZINE MACHINE HAND DRILL HAND DRILL COPPER CLAD COPPER CLAD LAMINATE LAMINATE TRANSFER PAPER ACETONE ACETONE ETCHING SOLUTION ETCHING SOLUTION SANDPAPER/SCRUB SANDPAPER/SCRUB PAPER TAPE PAPER TAPE 7/1/20XX Pitch deck title 9 1. PRINTING THE PCB LAYOUT ON A PAPER FIRST, PRINT THE LAYOUT ON THE PAPER OR MAGAZINE. HERE, WE HAVE MADE MULTIPLE COPIES OF THE LAYOUT JUST TO DEMONSTRATE THAT WE CAN MAKE MULTIPLE BOARDS WITH A SINGLE PAPER. 7/1/20XX Pitch deck title 10 1. PRINTING THE PCB LAYOUT ON A PAPER IN THIS METHOD, WE WILL TAKE A PRINT OF THE PCB LAYOUT ON A PIECE OF SPECIAL PAPER USING LASER PRINTER AND TRANSFER THE TONER FROM THE PAPER ON TO THE PCB BOARD USING HEAT TRANSFER (IRON BOX). 7/1/20XX Pitch deck title 11 2. GETTING THE BOARD READY FOR TONER TRANSFER NOW, CUT THE PIECE OF PAPER WITH LAYOUT PRINTED ON IT. SELECT THE SIZE OF THE PAPER A LITTLE BIT LARGER THAN THE FINAL SIZE OF THE BOARD SO THAT YOU CAN WRAP THE PAPER AROUND THE BOARD. 7/1/20XX Pitch deck title 12 2. GETTING THE BOARD READY FOR TONER TRANSFER TAKE A COPPER CLAD PCB BOARD AND MARK THE SIZE OF THE BOARD ON ONE CORNER. IN OUR CASE, IT WAS A RECTANGLE OF SIZE 4CM X 3CM. 7/1/20XX Pitch deck title 13 2. GETTING THE BOARD READY FOR TONER TRANSFER CUT THE SMALL BOARD USING A SAW. BEFORE CUTTING THE BOARD WITH SAW, USE A SHARP TOOL LIKE A BOX CUTTER AND MAKE FINE GROVES ON THE SURFACE. THIS WILL ALLOW YOU TO EASILY CUT THE BOARD USING THE SAW. 7/1/20XX Pitch deck title 14 2. GETTING THE BOARD READY FOR TONER TRANSFER NOW, THE SURFACE OF THE BOARD (THE ONE WE JUST CUT) IS NOT CLEAN WITH DEPOSITS OF FINGERPRINTS AND DIRT. SO, IN ORDER TO CLEAN THE SURFACE, USE A MILD EMERY PAPER, SAND PAPER OR SCRUB AND A clean board with the surface dirt removed will RUB IT ON THE COPPER look very shiny SIDE OF THE BOARD. 7/1/20XX Pitch deck title 15 2. GETTING THE BOARD READY FOR TONER TRANSFER NOW, CLEAN THE COPPER SIDE OF THE BOARD WITH ALCOHOL. IF YOU DO NOT HAVE ALCOHOL, YOU CAN USE ACETONE (ALSO AVAILABLE AS NAIL PAINT REMOVER). THIS STEP WILL COMPLETELY REMOVE THE SMALL DEPOSITS OF COPPER POWDER (CAUSED BY RUBBING WITH SAND PAPER) AND DIRT FROM THE SURFACE OF THE BOARD. 7/1/20XX Pitch deck title 16 2. GETTING THE BOARD READY FOR TONER TRANSFER NOW, TAKE THE COPPER BOARD AND PLACE IT ON THE PAPER WITH THE LAYER PRINT FACING THE COPPER SIDE. WRAP THE BOARD WITH THE EXTRA PAPER WE HAVE AND SEAL IT TIGHTLY WITH GLUE OR ADHESIVE TAPE. 7/1/20XX Pitch deck title 17 2. GETTING THE BOARD READY FOR TONER TRANSFER FOR MAGAZINE, TAKE THE COPPER BOARD AND PLACE IT ON THE MAGAZINE WITH THE LAYER PRINT FACING THE COPPER SIDE. WRAP THE BOARD WITH THE EXTRA PAPER WE HAVE AND SEAL IT TIGHTLY WITH GLUE OR ADHESIVE TAPE. 7/1/20XX Pitch deck title 18 3. TRANSFERRING THE TONER FROM PAPER TO PCB TRANSFER THE TONER FROM THE PAPER ON TO THE COPPER SIDE OF THE BOARD USING AN IRON BOX/LAMINATING MACHINE 7/1/20XX Pitch deck title 19 3. TRANSFERRING THE TONER FROM PAPER TO PCB FOR THE MAGAZINE, DAMP THE MAGAZINE PAPER WITH POLISH REMOVER TO TRANSFER THE IMAGE. USE A SPONGE TO REMOVE EXCESS PAPER (WHITE AREA) 7/1/20XX Pitch deck title 20 3. TRANSFERRING THE TONER FROM PAPER TO PCB PLACE THE BOARD (WITH PAPER STILL WRAPPED AROUND IT) IN A BOWL OF WATER. BE CAREFUL WHEN TOUCHING THE BOARD AS IT MIGHT BE VERY HOT. USE THE WATER FROM THE BOWL AND RUB OFF THE PAPER FROM THE BOARD. DO NOT APPLY TOO MUCH PRESSURE WHILE REMOVING THE PAPER. 7/1/20XX Pitch deck title 21 3. TRANSFERRING THE TONER FROM PAPER TO PCB WHEN THE PAPER IS COMPLETELY REMOVED, YOU CAN SEE A CLEAN TRANSFER OF THE TONER ON THE COPPER CLAD BOARD. 7/1/20XX Pitch deck title 22  4. ETCHING THE COPPER FROM BOARD REMOVE ALL THE UNNECESSARY COPPER FROM THE PCB BOARD. TAKE A SPOON OR TWO OF FERRIC CHLORIDE POWDER AND PUT IT IN A THICK PLASTIC OR STEEL CONTAINER. POUR SOME HOT WATER IN THE CONTAINER. 7/1/20XX Pitch deck title 23  4. ETCHING THE COPPER FROM BOARD DROP THE PCB IN THE CONTAINER AND STIR THE WATER FOR 10 TO 15 MINUTES (OR UNTIL THE COPPER IS COMPLETELY ETCHED). 7/1/20XX Pitch deck title 24  4. ETCHING THE COPPER FROM BOARD DISPOSE OF THE WATER CAREFULLY AND ADD FRESH WATER IN THE CONTAINER. NOW, PLACE THE PCB IN THE WATER TO CLEAN OF THE SURFACE FROM CHEMICAL DEPOSITS. 7/1/20XX Pitch deck title 25  4. ETCHING THE COPPER FROM BOARD TAKE ANOTHER PIECE OF MILD EMERY PAPER AND SLOWLY CLEAN THE TONER FROM THE PCB. YOUR PCB IS READY! 7/1/20XX Pitch deck title 26  5. DRILLING HOLES ON THE PCB NEXT STEP IS TO DRILL HOLES ON THE PCB TO MOUNT THE COMPONENTS. WE USED A SMALL HAND DRILL (MOTORIZED DRILL) TO MAKE THE HOLES. ONCE ALL THE HOLES ARE DRILLED, YOUR PCB IS READY FOR ASSEMBLY. 7/1/20XX Pitch deck title 27  6. PCB ASSEMBLY COLLECT ALL THE COMPONENTS REQUIRED FOR ASSEMBLING ON THE PCB. PLACE ALL THE COMPONENTS IN THEIR RESPECTIVE POSITIONS AND CHECK IF ALL THE HOLES, TRACKS AND PADS ARE AS EXPECTED OR NOT. 7/1/20XX Pitch deck title 28  6. PCB ASSEMBLY START SOLDERING THE COMPONENTS ON THE PCB. ONCE DONE, THE BOTTOM OF THE BOARD LOOKS SOMETHING LIKE THIS. AND THIS IS THE FINAL PCB WITH ALL THE COMPONENTS ASSEMBLED. 7/1/20XX Pitch deck title 29 WET PCB ETCHING USING ACIDIC AND ALKALINE METHODS  1. ACIDIC ETCHING used to etch off the inner layers in a rigid PCB. ). involves chemical solvents like Ferric chloride (FeCl3) OR Cupric Chloride (CuCl2). The acidic method is more precise and cheaper but time-consuming, compared to the alkaline method. implemented for the inner layers because the acid doesn’t react with the photoresist and doesn’t damage the required part. 7/1/20XX Pitch deck title 31  1A. CUPRIC CHLORIDE ETCHING most widely used etchant since it accurately etches off smaller features provides a constant etch rate and continuous regeneration, comparatively at a lower cost this type of etching is used to etch fine line inner layers 7/1/20XX Pitch deck title 32  1B. FERRIC CHLORIDE ETCHING has limited usage in the industry because of the costly disposal of the copper-containing etchant an attractive spray etchant because of its ease of use, holding capacity for copper, and the ability to be used in infrequent batch applications can be used with screen ink, photoresist, and gold patterns, but it cannot be used with tin or tin/lead resists. 7/1/20XX Pitch deck title 33  2. ALKALINE ETCHING PROCESS used to etch off the outer layers in a PCB chemicals utilized are chloride copper (CuCl2, 2H2O) + hydrochloride (HCl) + hydrogen peroxide (H2O2) + water (H2O) composition a fast process and is a bit expensive as well whole process is implemented in a conveyorized, high-pressure spray chamber where the PCB is exposed to a refreshed spray of etchant 7/1/20XX Pitch deck title 34  2. ALKALINE ETCHING PROCESS During the etching process, the point at which the etching of the unwanted copper is complete is called the breakpoint. The parameters for this process must be diligently followed since the solvent can damage the board if it is in contact for a longer period. The process must be well controlled. 7/1/20XX Pitch deck title 35  2. ALKALINE ETCHING PROCESS ALKALINE ETCHING MACHINE 7/1/20XX Pitch deck title 36  SUMMARY Methods of PCB Etching 1. Printing the PCB Layout on a Paper 2. Getting the Board Ready for Toner Transfer 3. Transferring the Toner from Paper to PCB 4.. Etching the Copper from Board 5. Drilling Holes on the PCB 6. PCB Assembly 7/1/20XX Pitch deck title 37  THANK YOU 7/1/20XX Pitch deck title 38