Effect of Multilayer versus Monolayer Dodecanethiol on Selectivity and Pattern Integrity in Area-Selective Atomic...

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Area-selective atomic layer deposition (AS-ALD) is crucial for fabricating advanced microelectronic devices.
• Controlling surface chemistry with self-assembled monolayers (SAMs) is key to achieving selective growth.
• Dodecanethiols (DDT) on copper surfaces are investigated for their potential in AS-ALD.

Purpose of the Study:

• To compare the effectiveness of monolayer and multilayer DDT in blocking atomic layer deposition (ALD) on copper surfaces.
• To investigate the interfacial effects at Cu/SiO2 patterns during area-selective ALD (AS-ALD).
• To understand the influence of DDT layer structure and ALD precursor chemistry on AS-ALD performance.

Main Methods:

• Vapor phase assembly of monolayer and multilayer dodecanethiols (DDT) on copper surfaces.
• Atomic layer deposition (ALD) of ZnO and Al2O3 using different precursors (diethylzinc, trimethylaluminum, water).
• Characterization of interfacial effects and growth behavior on Cu/SiO2 patterns using scanning electron microscopy and other surface analysis techniques.

Main Results:

• Multilayer DDT is approximately 7 times more effective at blocking ZnO ALD than monolayer DDT.
• Monolayer DDT is more effective than multilayer DDT in blocking Al2O3 ALD.
• Interfacial effects, including gaps and nucleation delays, were observed for ZnO ALD on multilayer DDT-coated patterns, dependent on pitch size and ALD chemistry.
• Al2O3 ALD grew on the TaN diffusion barrier, while ZnO ALD did not, highlighting the dependence on ALD chemistry.

Conclusions:

• The structure of the DDT layer (monolayer vs. multilayer) significantly impacts its ability to block different ALD processes.
• ALD precursor chemistry plays a critical role in the success of AS-ALD, influencing growth on both the target surface and diffusion barriers.
• Tailoring both the self-assembled layer structure and ALD chemistry is essential for optimizing AS-ALD for microelectronic fabrication.