Frequently Asked Questions

Q: Who is using the Focus Monitor Reticle?

The PSFM reticle is employed by both lithography tool manufacturers and end users. Major chipmakers throughout the world use the PSFM reticle in a variety of applications.

The PSFM Reticle is compatible with all brands of scanner and stepper-lithography equipment; data has been collected on ASML, Nikon, Canon, Ultratech Stepper and other older system brands such as SVGL and GCA.

Q: How much time can be saved using the Reticle?

When the PSFM reticle is used to determine and regularly monitor best focus, substantial savings in time can be realized vs. the on-board focus methods. Since focus monitoring can be achieved by running a single wafer lot, productive lithography tool uptime is minimally affected. On-board methods generally require clearing and restarting of the integrated wafer track, which can result in hours of lost productivity. All metrology for PSFM wafers can be done using overlay tools outside of the litho cell.

Q: Which lithography systems is the PSFM reticle compatible with?

The PSFM reticle is presently used on every brand of stepper-lithography tool (Both step-and-repeat and step-and-scan systems) available, including:

• ASML

• Nikon

• Canon

• Ultratech

• SVGL

• GCA/ISI

Customer-gathered data is available for most of these systems, and a list of technical papers can be found in our Tools & Resources section.

Q: Which overlay measurement tools is the PSFM Reticle compatible with?

The PSFM reticle allows data to be automatically collected and analyzed by several overlay measurement tools, including those brands from KLA-Tencor, NanoMetrics, Biorad, and IVS.

Standard software available on these systems can be used for rapid evaluation of the focus data collected, and other software solutions can be used (go to PSFM DATA!^TM Focus Analysis Software for more information).

For information on whether your metrology tool is compatible with the PSFM reticle, contact us.

Q: Can I use the same Focus Monitor Reticle to evaluate focus on several systems?

This depends on a variety of factors:

• The number of lithography systems to be supported

• The glass substrate size

• The wavelength of these steppers

• The field size

• The reduction factor (1X, 4X, 5X or 10X)

Contact us for further information.