Cascade Microtech P800-S - Manual (Page 6)

PN 151-853-A www.cascademicrotech.com Pyramid Probe Card: P800-S Online Cleaning• 6
Procedure: Determining Cleaning Parameters
Use the following procedure to determine cleaning parameters (cleaning interval, touchdowns per clean, and cleaning
overtravel).
1. Ensure that the proper cleaning medium is installed on the cleaning chuck or wafer.
2. Verify that the prober is set for the correct height offset or will detect the height of the cleaning surface optically. MIPOX
International’s WA6000-SWE film thickness varies from 470 to 500 µm.
3. Before installing the card in the prober, examine the probe tips under a microscope. Magnification levels of 500 to 1000x
and bright-field lighting are optimal. Typical probe-tip dimensions are:
• 18 µm nominal for fine-pitch solder balls
• 25 µm nominal for wide-pitch solder balls
4. Verify the prober cleaning settings.
• Cleaning Type set to Z-only
• The XY increment between cleaning touchdowns is at least 2 times the tip diameter
5. Choose initial cleaning overtravel in the range of 35 to 75 µm. 50 µm is the recommended.
6. Determine the cleaning interval.
a. Probe until a yield drop occurs.
b. Clean the probe tips very well with 150-200 cleaning cycles.
c. Repeat steps a and b enough times until you can predict the number of die probed before a yield drop.
d. Set the cleaning interval to be about 75 or 80% of the average number of touchdowns before yield drops.
7. Determine the number of touchdowns per cleaning cycle.
a. Choose an initial value. Traditionally, this has been a small number like 10 to 20. Recent experiments show that
more cleaning touchdowns may increase the number of die between cleaning. Consider starting with 150 to 200
cleaning touchdowns, especially for solder ball probing.
b. Probe several cleaning cycles to validate a stable process.
c. Reduce the number of cleaning touchdowns by about 20%.
d. Repeat steps b and c until the yield can not be maintained for the entire probing cycle.
e. Increase the number of cleaning touchdowns to the previous, larger, number.
8. Remove the probe card and examine the probe tips under a microscope for signs of contamination buildup. See
Contaminants on page 1 for information on contamination type, if any, building up on the probe tips.
N OTE
Cleaning parameters quoted here are guidelines only. Optimized cleaning parameters for
the best yield and lifetime must be developed in your unique probing environment.
C AUTION
Difficulty auto-focusing on the probe tips can cause actual and programmed overtravel to be
different. This can lead to poor cleaning performance.
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Online Cleaning Instructions