Cleaning process for EUV optical substrates
AssigneeThe Regents of the University of California
InventorsFrank J. Weber, Eberhard A. Spiller
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Abstract
A cleaning process for surfaces with very demanding cleanliness requirements, such as extreme-ultraviolet (EUV) optical substrates. Proper cleaning of optical substrates prior to applying reflective coatings thereon is very critical in the fabrication of the reflective optics used in EUV lithographic systems, for example. The cleaning process involves ultrasonic cleaning in acetone, methanol, and a pH neutral soap, such as FL-70, followed by rinsing in de-ionized water and drying with dry filtered nitrogen in conjunction with a spin-rinse.
Claims24
A process for cleaning optical surfaces, comprising:
- sequential ultrasonic cleaning in acetone, methanol, and a pH neutral soap solution,
- rinsing in de-ionized water,
- spin-rinsing, and
- blow-drying.
A process for cleaning surfaces having very demanding cleanliness requirements, comprising:
- sequentially immersing and ultrasonically cleaning in acetone, methanol, and a pH neutral soap solution,
- rinsing in de-ionized water and
- spin-rinsing with de-ionized water, immediately followed by blow-drying with dry filtered nitrogen while spinning.
Dependencies are inferred from the claim text.