Instructions for Amtetcher Oxide Etch Process Qualification
Purpose: to provide verification and trend of the oxide
program including etch rates of poly and photoresist, selectivity of those
materials, and wafer-to-wafer and within-a-wafer uniformity of etch.
of the test: to be completed after
major maintenance such as cleaning or gas line replacement or on a set schedule
to be determined or as needed based on user feedback.
of results: to be posted on the log
sheet located in the assigned book at the tool, posted in the equipment archive
for amtetcher on the SNF website and in a file or webpage available to users in
data or chart format.
- Use wafers with at least 900A thermal oxide, no
pattern. Patterned wafers may be
used to measure photoresist etch rates, too.
- Season the chamber for 10 minutes using Program
3. Be sure to check the program
parameters before starting.
- Measure oxide and photoresist thickness using one of
the Nanospecs. Be sure to use
reference wafer before testing to calibrate the tool. Take readings for the Center, Top,
Flat, Right and Left positions of the wafer. Readings should be taken about 15mm from the edge. See Fig. 2.
- Place two wafers into tray #1 in positions 2 and
3. See Fig. 1.
- Etch for 2 minutes.
Monitor gas flows, RF power and bias and record on Monitor Log
- Measure oxide and photoresist thickness using the
same Nanospec. Be sure to use
reference wafer before testing to calibrate the tool. Take readings for the Center, Top, Flat,
Right and Left positions of the wafer.
Readings should be taken in roughly the same place as the first
measurements. See Fig. 2.
- Record results on the Monitor Log. Record results in data file to get
wafer-to-wafer and within-a-wafer
- Subtract the second average reading from the first
average reading for oxide and for photoresist to get total material
- To get the etch rate per minute divide the average
total material etched measurements by 2.
- To get the selectivity for oxide vs photoresist
divide the oxide etch rate by the photoresist etch rate
Figure 1: Tray #1 with wafers
Figure 2: Reading
placement. Note that the “flat” is