How to clean a sample prior to lithography

Cleaning of substrates / samples should always be done in the fume cupboard. Lab coat, goggles and gloves should be worn at all times.

Use clean glassware, the ultrasonic bath should be ~half full of water, top up with ultrapure water or distilled if required and samples should be placed in clean glassware, just covered in solvent in the bath.

The nitrogen should be on at the bottle and the N2 gun line should be set to 1 bar.

(1) 8 minutes in ethyl lactate (yellow bottle) in the ultrasonic bath.

Dry with the nitrogen gun.

(2) 8 minutes in acetone in the ultrasonic bath.

Do not dry with the nitrogen gun as actetone fumes are to be avoided.

(3) Rinse with methanol then 8 minutes in the ultrasonic bath.

Dry with the nitrogen gun.

(4) 8 minutes in isopropanol (blue bottle) in the ultrasonic bath.

Finally dry the samples and put into a clean beaker. The samples are now clean and ready to use.

Between the stages the beakers should be cleaned. to do this, wash out the beaker with the same chemicals in order as above and place upside down at the back of the fume cupboard on a tissue to dry. Once dry they can be used again or put into the glassware cupboard.

If the wash bottles get low/empty, they can be refilled by topping up from the main store bottles in the chemical cupboard. bottles should be topped up in the fume cupboard and any spillage wiped off the main bottle before being put back into the cupboard.

When finished turn off the nitrogen both at the main bottle and at the fume cupboard.