An embedded neutral layer for advanced surface affinity control in grapho-epitaxy directed self-assembly

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Manufacturing

Background:

• Directed self-assembly (DSA) is a key technique for advanced semiconductor patterning.
• Grapho-epitaxy relies on topographical guiding structures to direct DSA.
• Controlling surface affinity within these structures is critical for reliable patterning.

Purpose of the Study:

• To achieve independent surface affinity control in grapho-epitaxy guiding structures.
• To evaluate and optimize a novel integration method for DSA grapho-epitaxy.
• To improve the reliability and uniformity of DSA-based semiconductor patterning.

Main Methods:

• Embedding an ultrathin layer with tunable surface properties within the guiding template stack.
• Utilizing a thin protective layer to preserve embedded layer properties during etching.
• Characterization using critical dimension scanning electron microscopy (CD-SEM) and focused ion beam-scanning transmission electron microscopy (FIB-STEM).
• Evaluation of DSA performance on 300 mm wafers using 193 nm immersion lithography.

Main Results:

• Independent control of surface affinity on the bottom and sidewalls of guiding structures was achieved.
• A protective layer successfully preserved the embedded layer's surface properties during etching.
• Controlled polymer residual thickness (few nanometers) and uniformity (inferior to 1 nm) at the guiding template bottom.
• Demonstrated high success rates and critical dimension uniformity for shrunk contacts.

Conclusions:

• The novel integration method provides advanced surface affinity control for grapho-epitaxy DSA.
• This approach enhances the reliability and uniformity of semiconductor patterning processes.
• The controlled polymer residual thickness facilitates subsequent DSA pattern transfer, advancing semiconductor manufacturing.