Cleaning processes account for over 25% of processing in microelectronic manufacturing , suggesting electronics to be one of the most chemical intensive markets in commerce. Industry roadmaps exist to reduce chemical exposure, usage, and waste . Companies are encouraged to create a safer working environment, or green factory, and ultimately become certified similar to LEED in the building industry . A significant step in this direction is the integration of aqueous-based photoresist (PR) strippers which eliminate regulatory risks and cut costs by over 50%. One of the largest organic solvent usages is based upon thick PR removal during bumping processes [4-6]. Using market projections and the benefits of recycling, it is estimated that over 1,000 metric tons (mt) of residuals originating from bumping processes are incinerated or sent to a landfill. Aqueous-based stripping would eliminate this disposal while also reducing the daily risks to workers and added permitting costs. Positive-tone PR dissolves in aqueous strippers while negative-tone systems are lifted-off from the substrate, bumps, pillars, and redistribution layers (RDL). While the wafers are further processed and rinsed, the lifted-off PR is pumped from the tank, collected onto a filter, and periodically back-flushed to the trash. The PR solids become a non-hazardous plastic waste while the liquids are mixed with the developer stream, neutralized, filtered, and in most cases, disposed to the sewer. Regardless of PR thickness, removal processes may be tuned to perform in <15min, performing at rates nearly 10X faster than solvents with higher bath lives. A balanced formula is safe for metals, dielectrics, and may be customized to any fab.
As the semiconductor industry continues to implement the ITRS (International Technology Roadmap for
Semiconductors) node targets that go beyond 45nm , the need for improved cleanliness between repeated process
steps continues to grow. Wafer cleaning challenges cover many applications such as Cu/low-K integration, where
trade-offs must be made between dielectric damage and residue by plasma etching and CMP or moisture uptake by
aqueous cleaning products. [2-5] Some surface sensitive processes use the Marangoni tool design  where a
conventional solvent such as IPA (isopropanol), combines with water to provide improved physical properties such as
reduced contact angle and surface tension. This paper introduces the use of alternative solvents and their mixtures
compared to pure IPA in removing ionics, moisture, and particles using immersion bench-chemistry models of various
processes. A novel Eastman proprietary solvent, Eastman methyl acetate is observed to provide improvement in ionic,
moisture capture, and particle removal, as compared to conventional IPA.  These benefits may be improved relative
to pure IPA, simply by the addition of various additives. Some physical properties of the mixtures were found to be
relatively unchanged even as measured performance improved. This report presents our attempts to cite and optimize
these benefits through the use of laboratory models.