Acid Hood
If you are etching III-Vs the only hood you are allowed to use is E02. Do not use a different hood for III-Vs (or Rico may cite you). The acid hood training is pretty easy and takes about an hour. Acids are no joke and we don't want any injuries.
When you are using the hoods, remember that a pirahna etch will eat through plastic, but an HF etch will eat through glass. For III-Vs, we don't normally use either etch but you may need them on occasion.
Some additional tips for using the Acid Hoods
PPE
- When putting on your PPE, start with the acid gown. You are looking for three things. First, make sure that the neck strap is solid and not fraying. Second, verify that the cuff elastics are tight. Third, look for any dried white crystals around the gown - this could be dried HF. If any of these issues are present, throw the gown away and get a new one. You should always try to use a gown that fits you well.
- Then put on the face shield. Rico likes to keep the knobs loose enough that he can flip the shield down by jerking his head forward. This minimizes the amount you have to actually use your hands to manipulate the shield.
- Then put on your gloves. Before putting them on, test them for pinholes. You can do this by closing off the end and compressing the glove, to see if it puffs up. If it doesn't, there is likely a leak, and the glove can be replaced. This step can also be done using the airgun at the hood.
Prior to pouring chemicals
Check that the aspirator is working by spraying some water into the sink and aspirating it.
If any of the alarms go off on the hood when you first turn it on, mute them.
When working with acids, nobody should ever approach you to talk to you or distract you. If they do, ignore them.
Do not walk around the cleanroom in acid hood garb. One exception is if you are walking straight to a chemical cabinet to retrieve a chemical bottle, and then walking immediately back to where you were working. Another possible exception is if you are walking back to triple rinse an empty bottle.
In general, follow the steps of the recipe/procedure you are using. Make sure you know the procedure before you start your work!
When pouring chemicals, pour slowly, and not from high above the container. Never put your gloved hands into chemicals that are sitting in a container - always grab it around the outside.
If you are etching III-Vs or metals, DO NOT aspirate the etchant. Instead, carefully carry over the etchant disposal bottle to your bench with a funnel. Carefully pour your etchant waste into that bottle. Then you can triple rinse the etchant container.
Always triple rinse your containers before and after use.