• Bulk Chemical Supplies
Changes in chemical quality can occur during in-house handling and storage. PR-23-MS activates
an alarm if the chemical is not within pre-set specifi cations and prevents wrong chemicals or
wrong concentrations from entering the process.
• Photoresist Development
The photoresist developer concentration has a significant influence on the photoresist
development step. An appropriate concentration of the developer should be maintained
to comprise both the fabricating throughput and the pattern resolution. PR-23-MS can be
used for real-time developer concentration monitoring instead of the traditional wafer-to-wafer
or run-to-run methods.
• Photoresist Stripping
As stripping of most photoresists is an acid/base neutralization process, the speed and quality
of photoresist stripping can be optimized by PR-23-MS when the strength of overall alkalinity is
• Wet Ethching
As temperature and concentration of the etching solution have major impact on the wet etch
rates, various etching processes can be optimized and etch end points determined when the
chemical concentration is known. For instance, the KOH etch process can be optimized when
the composition of heated KOH/H2O solution is continuously monitored with PR-23-MS.
• Post Etch Wafer Cleaning
PR-23-MS measures the concentration of expensive cleaning chemicals and polymer removals,
such as EKC-265 in the post etch wafer cleaning. This provides a real-time indication of the
bath and assists in increasing the bath lifetime and wafer pass in, and in reducing the chemical
• Chemical Mechanical Planarization
PR-23-MS provides a method for concentration monitoring of acids and chemicals, such as HF
or HCl in the CMP abrasive slurries. This information can be used to determine the end point
and to achieve a better uniformity of the planarization process.