Etching the PCB - Revision history

Aplstudent: /* Etching with the Aggregation Tank */

2019-04-16T23:39:33Z

‎Etching with the Aggregation Tank

Aplstudent: /* After Etching */

2019-03-12T19:30:46Z

‎After Etching

Aplstudent: /* After Etching */

2019-03-11T20:22:55Z

‎After Etching

Aplstudent at 20:48, 9 March 2019

2019-03-09T20:48:33Z

Aplstudent at 20:48, 9 March 2019

2019-03-09T20:48:13Z

Aplstudent at 20:39, 9 March 2019

2019-03-09T20:39:08Z

Aplstudent at 20:38, 9 March 2019

2019-03-09T20:38:55Z

Aplstudent at 20:37, 9 March 2019

2019-03-09T20:37:53Z

Aplstudent: /* After Etching */

2019-03-09T20:22:49Z

‎After Etching

Aplstudent: /* Etching with the Aggregation Tank */

2019-03-09T20:15:05Z

‎Etching with the Aggregation Tank

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 ===Etching with the Aggregation Tank===
-Before you start the etching process you will want to set up the thermometer in the aggregation tank, turn on the heating pillar by plugging it in, start the bubbler by plugging it in, and set up a tray of water/sodium bicarbonate mix (this mix should contain very roughly 1 tablespoon of sodium bicarbonate and 500 mL of water). The sodium bicarbonate will be used to neutralize the HCl in the CuCl2 and halt the etching process after you are finished. While increasing the temperature increases etching speed, it also boils off more HCl (which has a very low boiling point). I recommend bringing the CuCl2 solution up to 32 degrees Celsius and then unplugging the heater. The solution should roughly maintain this temperature for the duration of the etching process without being plugged back in.
+Before you start the etching process you will want to set up the thermometer in the aggregation tank (this thermometer can fall into the tank and is difficult to remove so use the attached wire to prevent this), turn on the heating pillar by plugging it in, start the bubbler by plugging it in, and set up a tray of water/sodium bicarbonate mix (this mix should contain very roughly 1 tablespoon of sodium bicarbonate and 500 mL of water). The sodium bicarbonate will be used to neutralize the HCl in the CuCl2 and halt the etching process after you are finished. While increasing the temperature increases etching speed, it also boils off more HCl (which has a very low boiling point). I recommend bringing the CuCl2 solution up to 32 degrees Celsius and then unplugging the heater. The solution should roughly maintain this temperature for the duration of the etching process without being plugged back in.
 The aggregator with the CuCl2 should look like this when set up, but make sure this is done under a fume hood (the HCl fumes are toxic and cause rust). Also make sure you have your sodium bircarbonate solution set up near by.

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 Once the acetone washes away the green photoresist, the board should look like this, with copper traces exposed on the layer of substrate:
 [[File:]]
 ====Etchant Warning====

← Older revision		Revision as of 20:22, 11 March 2019
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	Once the board is clean, we want to remove the remaining photoresist from the copper traces. Pour a very small amount of acetone over the board and you should see the green layer disappear to reveal your copper traces. This step is necessary so you will be able to solder components to the copper of the board.		Once the board is clean, we want to remove the remaining photoresist from the copper traces. Pour a very small amount of acetone over the board and you should see the green layer disappear to reveal your copper traces. This step is necessary so you will be able to solder components to the copper of the board.
		+
		+	Once the acetone washes away the green photoresist, the board should look like this, with copper traces exposed on the layer of substrate:
		+
		+	[[File:]]

	====Etchant Warning====		====Etchant Warning====

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 Hydrochloric acid (HCl) is very acidic and should not touch your skin and copper chloride is extremely harmful to water treatment plants, so DO NOT pout this solution down the drain (see the warning in the [[Etching the PCB#After Etching|After Etching]] section). Fortunately, there should be no need to dispose of any etchant because the etchant is reusable after the etching process (see how in the [[Etching the PCB#Technical Information| Technical Information]] section).
-Also note that the fumes from the etchant are dangerous, thus the etchant should only be opened an used under a fume hood (Dr.Boggs has access to one in CAMCOR).
+Also note that the fumes from the etchant are dangerous, thus the etchant should only be opened and used under a fume hood (Dr.Boggs has access to one in CAMCOR).
 ==Testing the CuCl2==

← Older revision		Revision as of 20:48, 9 March 2019
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	Hydrochloric acid (HCl) is very acidic and should not touch your skin and copper chloride is extremely harmful to water treatment plants, so DO NOT pout this solution down the drain (see the warning in the [[Etching the PCB#After Etching\|After Etching]] section). Fortunately, there should be no need to dispose of any etchant because the etchant is reusable after the etching process (see how in the [[Etching the PCB#Technical Information\| Technical Information]] section).		Hydrochloric acid (HCl) is very acidic and should not touch your skin and copper chloride is extremely harmful to water treatment plants, so DO NOT pout this solution down the drain (see the warning in the [[Etching the PCB#After Etching\|After Etching]] section). Fortunately, there should be no need to dispose of any etchant because the etchant is reusable after the etching process (see how in the [[Etching the PCB#Technical Information\| Technical Information]] section).
		+
		+	Also note that the fumes from the etchant are dangerous, thus the etchant should only be opened an used under a fume hood (Dr.Boggs has access to one in CAMCOR).

	==Testing the CuCl2==		==Testing the CuCl2==

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 The APL has a container of etchant, copper chloride (CuCl2) mixed with hydrochloric acid (HCl), that should be used for etching the PCB. These chemicals are dangerous and should be handled with care.
-Hydrochloric acid (HCl) is very acidic and should not touch your skin and copper chloride is extremely harmful to water treatment plants, so DO NOT pout this solution down the drain (see the warning in the [[Etching the PCB#After Etching|After Etching]] section). Fortunately, there should be no need to dispose of any etchant because the etchant is reusable after the etching process (see why in the [[Etching the PCB#Technical Information| Technical Information]] section).
+Hydrochloric acid (HCl) is very acidic and should not touch your skin and copper chloride is extremely harmful to water treatment plants, so DO NOT pout this solution down the drain (see the warning in the [[Etching the PCB#After Etching|After Etching]] section). Fortunately, there should be no need to dispose of any etchant because the etchant is reusable after the etching process (see how in the [[Etching the PCB#Technical Information| Technical Information]] section).
 ==Testing the CuCl2==

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 ===After Etching===
-Once etching is complete, remove the board from the etchant. Try to shake as much etchant as possible back off into the tank before putting the board into a prepared small tray of sodium bicarbonate solution. This will immediately halt the etch action, and remove all remaining copper ions from the etchant solution that remained to the board. This is important because putting copper ions down the drain is very illegal:
+Once etching is complete, remove the board from the etchant with a gloved hand. Try to shake as much etchant as possible back off into the tank before putting the board into a prepared small tray of sodium bicarbonate solution. This will immediately halt the etch action, and remove all remaining copper ions from the etchant solution that remained to the board. You will see light blue particles form in the sodium bicarbonate solution when it contacts the etchant.Gentle brushing will take any copper bicarbonate (the light blue particles) off the board.
 https://nature.nps.gov/water/ecencyclopedia/assets/contaminant-pdfs/copper.pdf
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 Under no circumstances allow any amount of green etchant solution to go down the drain! If any does, dump the sodium bicarbonate in immediately, chase it with a torrent of water, and pour additional bicarbonate in the sink straight from the box to 'kill it' before it enters the wastewater stream. If substantial spillage (more than a thimble full) occurs, get Dr. Boggs and call EHS immediately. A large release of copper ions down the drain threatens the entire city's wastewater treatment plant.'''
 ===Technical Information===