Fifteen Nanometer Resolved Patterns in Selective Area Atomic Layer Deposition-Defectivity Reduction by Monolayer...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Selective area atomic layer deposition (SA-ALD) is crucial for advanced semiconductor fabrication, offering a potential replacement for lithography.
• Self-assembled monolayers (SAMs) are investigated as potential blocking layers to control SA-ALD.
• Understanding SAM barrier properties and failure mechanisms is key to enabling defect-free SA-ALD.

Purpose of the Study:

• To synthesize and explore structure-property relationships of SAM derivatives for SA-ALD.
• To evaluate the effectiveness of different SAM functionalities as barriers in ALD processes.
• To develop a material enabling high-resolution SA-ALD and demonstrating its use as an etch mask.

Main Methods:

• Synthesis of various SAM derivatives with different side group functionalities.
• Evaluation of SAMs as blocking layers during the deposition of a sacrificial etch mask via ALD.
• Characterization of defectivity in selectively deposited ALD films at various feature sizes.
• Assessment of the selectively deposited film as an etch mask for selective metal removal.

Main Results:

• Weakly interacting SAMs (van der Waals) enabled selective deposition but showed defects below 100 nm.
• Stronger noncovalent interactions (hydrogen bonding, pi-pi) did not improve barrier performance.
• Reactive SAMs that polymerized on the surface provided effective barriers, drastically reducing defects.
• Polymerized SAMs enabled selective ALD with critical dimensions as low as 15 nm.
• The selectively deposited film served as an effective etch mask for selective metal removal.

Conclusions:

• Polymerizable SAMs are highly effective barriers for SA-ALD, enabling defect reduction.
• This approach allows for high-resolution patterning (down to 15 nm) crucial for next-generation semiconductor devices.
• The developed SA-ALD process and materials facilitate the use of selectively deposited films as etch masks, removable under mild conditions.