Lab IB: Photoresist Application and Ashing
Your team will be divided into two groups for this experiment. One group will be
applying photresist with the spinner and the other will be
ashing it away using the plasma etcher. Resist thickness will
be measured by ellipsometry and profilmetry.
- Using pieces of silicon provided apply photoresist as instructed in the photolithography procedure. Investigate the influence of spin speed
on resist thickness and uniformity in the range of 2000 - 5000 rpm. * IMPORTANT* You will
not be exposing wafers in this experiment. Instead of performing the softbake for 45
seconds. Extend the time to 90 seconds. At this point the wafer is ready for
characterization and stripping.
- Attemp to characterize the resist thickness using ellipsometry.
- Ash the photresist using an oxygen plasma. Use the plasma etcher in manual mode as
described in the etching procedures. Investigate the influence
of plasma power between 200 - 600 W on etch rate and uniformity. Oxygen will be the
only gas used and it will be supplied through Gas Line #2 To give us the most
complete picture each group will use a pressure:
Group 1: P = 700 mTorr;
Flow = 100%
Group 2: P = 550 mTorr; Flow = 80%
Group 3: P = 400 mTorr; Flow = 60%
- During some of your etches cover 1/2 the sample with a glass slide. Characterize the
step height using the profilometer.