Area-selective atomic layer deposition of platinum using photosensitive polyimide

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Area-selective atomic layer deposition (AS-ALD) is crucial for fabricating nanoscale electronic devices.
• Platinum (Pt) deposition requires precise patterning for advanced applications.
• Existing masking materials like poly(methyl-methacrylate) (PMMA) have limitations in thermal stability and pattern resolution.

Purpose of the Study:

• To investigate the use of photosensitive polyimide as a masking layer for area-selective atomic layer deposition of platinum.
• To evaluate the performance of polyimide in AS-ALD of Pt compared to traditional masking materials.
• To demonstrate the capability of polyimide for achieving high-resolution Pt patterning at elevated temperatures.

Main Methods:

• Spin-coating and photolithography were used to prepare and pattern photosensitive polyimide films.
• Area-selective atomic layer deposition (AS-ALD) of platinum was performed using the polyimide as a mask.
• Polyimide removal was achieved using hydrogen plasma post-deposition.
• Poly(methyl-methacrylate) (PMMA) was used as a reference masking layer for comparison.

Main Results:

• Polyimide exhibited excellent selectivity for Pt deposition, with less than a monolayer deposited after 1000 ALD cycles.
• Polyimide demonstrated superior temperature stability compared to PMMA, leading to improved uniformity and pattern definition.
• The absence of reflow contamination with polyimide significantly shortened the nucleation phase during Pt ALD.
• Pt patterns down to 3.5 μm were achieved at 300 °C, a tenfold improvement over PMMA.

Conclusions:

• Photosensitive polyimide is a highly effective masking material for area-selective atomic layer deposition of platinum.
• The polyimide process offers significant advantages in terms of selectivity, thermal stability, pattern resolution, and nucleation efficiency.
• This technique shows great promise for nanoscale patterning of platinum, with potential for features down to 100 nm.