Selective Ru ALD as a Catalyst for Sub-Seven-Nanometer Bottom-Up Metal Interconnects

Area of Science:

• Microelectronics Engineering
• Materials Science
• Surface Chemistry

Background:

• Area-selective atomic layer deposition (AS-ALD) is crucial for advanced microelectronics.
• Existing methods like self-assembled monolayers face limitations in defectivity and downscaling.
• Understanding surface modification is key to unlocking AS-ALD's potential.

Purpose of the Study:

• To develop a scalable surface modification process for AS-ALD.
• To demonstrate selective inhibition of ALD nucleation on specific materials.
• To enable novel bottom-up fabrication routes for 3D nanostructures.

Main Methods:

• Utilized hydrogen (H2) plasma treatment to modify amorphous carbon surfaces.
• Investigated the nucleation and growth of ruthenium (Ru) ALD on modified and unmodified surfaces.
• Applied AS-ALD for bottom-up electroless metal deposition in a dual damascene scheme.

Main Results:

• Achieved selective inhibition of Ru ALD nucleation on amorphous carbon using H2 plasma.
• Demonstrated instantaneous nucleation and linear growth on Si-containing materials.
• Enabled etch-damage-free, low-k replacement for fabricating ultrafine 3D nanostructures.

Conclusions:

• H2 plasma surface modification offers a viable and scalable strategy for AS-ALD.
• This approach overcomes limitations of previous methods, facilitating microelectronics fabrication.
• AS-ALD provides a pathway to complex 3D nanostructures without subtractive patterning or CMP.