Molecular layer deposition of functional thin films for advanced lithographic patterning

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Photoresist materials are critical for lithography, enabling the miniaturization of electronic devices.
• Current photoresists face challenges in meeting the demands of shrinking device sizes.
• Developing advanced photoresists is essential for continued progress in semiconductor technology.

Purpose of the Study:

• To introduce molecular layer deposition (MLD) for creating photoresist materials with precisely controlled functional group placement.
• To demonstrate the synthesis and characterization of novel polyurea-based photoresists.
• To showcase the utility of these MLD-fabricated resists in UV patterning.

Main Methods:

• Utilized molecular layer deposition (MLD) for layer-by-layer synthesis of polyurea films.
• Employed urea coupling reactions between 1,4-phenylene diisocyanate (PDIC) and diamine monomers (ED or PDDE).
• Incorporated acid-labile groups at defined positions within the polyurea backbone.
• Characterized film morphology and composition using atomic force microscopy (AFM).

Main Results:

• Achieved linear growth and stoichiometric composition in MLD-deposited polyurea films.
• Demonstrated controllable incorporation of acid-labile groups within the resist structure.
• Confirmed acid-catalyzed cleavage of the polyurea backbone at specific sites.
• Successfully utilized the polyurea films as photoresists for UV patterning after PAG treatment.

Conclusions:

• Molecular layer deposition (MLD) offers a novel route for fabricating molecularly designed photoresist films.
• This approach provides precise control over resist chemistry and structure for advanced lithography.
• The developed polyurea resists show promise for next-generation electronic device fabrication.