What we're looking for

We are looking for a novel photosensitive insulating material or a new method to induce photosensitivity to resin materials that goes beyond those currently used in industrial applications, specifically for semiconductor back-end processes. While polyimide is preferred, other resin types may also be acceptable. The ideal material should ensure semiconductor package reliability and minimize transmission loss by exhibiting low water absorption, high adhesion, low dielectric constant (Dk), and low dielectric loss (Df).

Solutions of interest include:

• Next-generation photosensitive polyimides
• New methods for imparting photosensitivity to polyimides
• Novel photosensitive high-heat-resistant resins beyond polyimides
• Advanced methods for imparting photosensitivity to high-heat-resistant resins

Our must-have requirements are:

• Photosensitive to i-line exposure wavelengths
• Enables patterning of line/space below 5 μm (L/S<10 μm acceptable) and via below 5 μm using i-line exposure

Our nice-to-have's are:

• Compatibility with semiconductor back-end processes, i.e., withstands soldering temperatures between 250 and 290°C with a resin glass transition temperature above 250°C
• Offers warpage control by achieving a low coefficient of thermal expansion (<40 ppm/K) and/or low modulus (<3 GPa)
• Aqueous developer is desirable; compatibility with an alkaline aqueous developer (e.g., TMAH aq.) is preferred, but organic developers (e.g., PGMEA and PEGME) are also acceptable

What's out of scope:

• Photoresist materials
• Processes or materials requiring hydrophobic solvents such as alkanes
• Solutions that require the use of hazardous solvents such as NMP and DMAc
• Restricted materials that do not comply with RoHS and REACH regulations
• Photosensitive systems with significant patent constraints used in existing redistribution layer (RDL) materials (e.g., negative-tone polyimide (PI) using a photo-acid generator (PAG) and acid crosslinking mechanism, unless it is differentiated from existing materials)