WAFER CLEANING AND WET ETCHING MODULE

General Policies

Purpose: to give the new user information about the lab policies regarding the transportation, handling, disposing and changing of chemicals at the wetbenches.

General Policies for the Use of Chemicals:

Do not attempt to handle or transport chemicals unless you have been properly trained and qualified. See a staff member if you need training.

You must have completed the Safety Module, read the MSDS for the chemicals you wish to use and know where the safety showers/eye washes are before you move or use chemicals.

When transporting or handling chemicals never work alone. You should be within shouting distance of another person.

Always use slow deliberate movements. Think about what you intend to do before you start.

Transportation of Chemicals:

Passthrough carts are stocked daily with commonly used chemicals.

If you need to use a non-standard chemical please see Tony Souza.

Chemicals may only be moved from the passthrough cart by using the transport cart or a bottle basket.

You must be wearing the appropriate protective apparel; apron, chemical goggles or face shield and black neoprene gloves.

Carefully examine the bottles you wish to use for drips, loose caps or other problems. If you are uncertain as to the status of a bottle contact a staff member.

Roll the cart slowly to the wetbench you intend to use. Avoid bumping into equipment, doors, etc...

Return the bottles to the properly marked slots. Be aware of storage compatibility of the chemicals you use. Make sure the chemicals are stored with chemicals of the same type.

Chemical Handling:

Wear the appropriate safety apparel; apron, chemical goggles or face shield and neoprene gloves with a flexiglove over them (for particulate control). Change flexigloves often when working in a critical area, i.e., the diffusion wetbench.

Always Add Acid to water (AAA) when pouring chemicals.

Do not mix solvents and acids. This may cause a violent reaction. You may use solvents only at a solvent bench.

Always work with acids or solvents in an exhausted hood. Be sure you open the bottle up far enough back in the wetbench or workstation so that the exhaust draws off the fumes.

Place the cap of the bottle upside down on the deck of the wetbench to prevent contamination from getting around the cap's edge and into the bottle when the cap is replaced on the bottle.

Do not touch the inside of the bottle cap or the area around the mouth of the bottle with your gloves, as you will contaminate the bottle.

If you suspect that you have contaminated the bottle cap, the bottle or it contents contact a staff member.

If any chemicals get on the outside of the bottle be sure to rinse and dry the bottle before replacing it to the proper slot in the passthrough cart.

Return the bottles to the properly marked slots. Be aware of storage compatibility of the chemicals you use. Make sure the chemicals are stored with chemicals of the same type.

Disposing and Changing of Chemical Baths:

Most of the wetbenches come with individual aspirators which are connected directly to the acid neutralization system.

HF may not be poured down the drain or aspirated. All the drains are connected to the neutralization system and it is illegal to dump HF or mixtures containing heavy metals into the system. There is a special HF drain which is connected to a holding tank. This tank is pumped out as needed.

Other chemicals which cannot be allowed into the acid neutraization system are; chrome solutions, solvents, photoresist, and fluorinated solutions. This is not a complete list. Ask a staff member if you are in doubt.

Several wetbenches are not connected to the acid neutralization system. The chemicals used at these wetbenches are collected in a carboy which is fitted to the bench. The equipment has an interlock which will not allow the enabling of the equipment if the carboy needs replacing. A staff member will label and remove the waste material.

If you have a chemical which you have determined to be waste (it's usuable life is over) contact a staff member to properly contain and label the chemical. After the waste is labled it is stored in a waste accumulation area (WAA) until Environmental Health and Safety picks it up to dispose of it.

Make sure that when you aspirate a chemical bath you fill out the form on top of the wetbench. Regulations require that we keep a record of chemical discharges into the acid neutralization system. It also allows us to record the chemical changes in order to keep fresh baths available throughout the lab.