Development of ArF immersion exposure tool

Advances in Patterning Materials for 193 nm Immersion Lithography

“…Most significantly, the refractive index of water is 1.437 at 193.4 nm and its absorption coefficient is 0.036 cm −1 ; , however, the measured absorbance of water at 193 nm is very sensitive to trace amounts of extrinsic contaminants. To meet the stringent property and stability requirements required for immersion lithography, water polishing systems are commonly installed to improve the fab deionized (DI) water stream before it enters the water conditioning systems of the scanner. , Water treatment systems remove dissolved gases, particles, soluble organic and inorganic compounds, bacteria, and other contaminants from water and provide the immersion tool with a high flow rate (up to 3 L/min) of water at a stable temperature (within a few mK). , …”

Immersion-Specific Defects of High-Receding-Angle Topcoat

“…These defect types originate in the bubbles on the TC surface based on the observation of the local magnification and/or demagnification of line features (generally, they are called swelling and slimming, respectively). 5,6) The embedded bubble refracts the exposure light and results in the pattern-pitch-changed circular defect. It is considered that the number of bubble defects increases with high-speed scanning exposure.…”