Best practices for handling chips

Silicon wafers and quartz wafers are cut into square pieces called “chips” or “dies” or “coupons”. Each chip is used as a table top for an experiment. All experimental physicists working in this field need to learn best practices for handling chips.

First, you should have your own pair of tweezers. Good tweezers cost about $30 a pair. They become an extension of your body. If they are dropped on the delicate end, they are ruined. Look after your tweezers well - they should last for five years.

Rounded-tip tweezers work well for handling chips.

Like your hands, your tweezers should always be clean. Typically, a researcher will wash their tweezers at the start of each day by sonicating in acetone for 60 seconds, then spraying with IPA and DI water and then blow drying with the N2 gun.

When you pick up a chip, don't let the tweezers go more than 2 mm past the edge

When you wash a chip, the spray from the bottle should be hit the chip and flow towards your tweezers. Don't put the tweezers upstream of the chip. This is easier said than done because liquid will tend to flow down the tweezers onto your gloves. Experiment with a dummy chip. Transition between acetone and IPA quickly, never let the acetone evaporate before you have a chance to rinse it off with IPA. Similarly, transition between IPA and DI water quickly.
Blow drying a chip can be tricky. Too much power and the chip flies out of your tweezers. Too little drying time and liquid remains under the tweezers. I like to support the chip on a cleanroom wipe while I blow off most of the liquid (be careful, the cleanroom wipe will flap around if you are not careful). Then I put down the chip and blow off the tweezers. Then I pick up the chip in a different spot and get any remaining liquid.

QR Code
QR Code best_practices_for_handling_chips (generated for current page)