On average there are 300 - 400 steps to make a silicon wafer full of semi-conductor chips. Generally, one third of the steps are chemical steps done using "wet benches". Wet Becnches clean, remove particles, remove photomask, condition the surface and more.
15-20 years ago, 20 2-3" silicon wafers may have been put in a rack and lowered into a tank by hand or using a small robotic arm. There was a timer for how long to leave it in the chemical. These "manual" benches had one or more tanks per bench. There are still some in use today.
Modern wet benches are completely automated. They can receive a rack of 12" wafers automatically from the previous equipment, and automatically move the rack through 6-8 tanks. Each rack of wafers may need different times in the tanks. These "automated" benches know when they can hold back one rack to process another one so they can juggle 3-4 racks with different recipes at the same time.
Think about this. If there are 500-600 state-of-the-art PC chips on each wafer and 30 wafers in a rack, how much do you think that rack of wafers is worth when it's done.
Subscribe to:
Post Comments (Atom)
1 comment:
Wow Bob, brings back memories. In my "past life" I worked for Hewlett Packard automating semiconductor manufacturing plants. We just starting to use robots then - full automation was only a dream - lol. Great article. Lori On Maui
Post a Comment