Ludovic Godet

A process for topographically selective deposition on 3D nanostructures by ion implantation

Area-selective atomic layer deposition (AS-ALD) is attracting increasing interest because of its ability to enable both continued dimensional scaling and accurate pattern placement for next-generation nanoelectronics. Here we report a strategy for depositing material onto three-dimensional (3D) nanostructures with topographic selectivity using an ALD process with the aid of an ultrathin hydrophobic surface layer. Using ion implantation of fluorocarbons (CFx), a hydrophobic interfacial layer is formed, which in turn causes significant retardation of nucleation during ALD. We demonstrate the process for Pt ALD on both blanket and 2D patterned substrates. We extend the process to 3D structures, demonstrating that this method can achieve selective anisotropic deposition, selectively inhibiting Pt deposition on deactivated horizontal regions while ensuring that only vertical surfaces are decorated during ALD. The efficacy of the approach for metal oxide ALD also shows promise, though further optimization of the implantation conditions is required. The present work advances practical applications that require area-selective coating of surfaces in a variety of 3D nanostructures according to their topographical orientation.

Post-Litho Line Edge/Width Roughness Smoothing by Ion Implantations

Solving the issue of line edge/width roughness (LER/LWR) in chip manufacturing is becoming increasingly urgent as the feature size continues to decrease. Several post-lithography processing techniques have been investigated by the semiconductor industry, but they were often proved to be inadequate in one area or another. In this study, a near isotropic ion implantation process, called Plasma Ribbon Beam Technology, was tuned for photoresist treatment and used to reduce LER/LWR by >30% while minimizing loss in the critical dimension (CD). Different implantation chemistries were evaluated and process parameters including energy, angle, beam current, and dose, were optimized. The LER/LWR measurement was performed on an SEM system designed for CD metrology. SEM images with resist lines of 3μm long were taken to capture more low frequency data. The results showed that, with Ar implantation on 193/193i photoresists, a 27-37% before-etch reduction in LER/LWR was achieved on 65nm and 45nm half-pitch lines whereas the CD change was controlled under ±1%. Preliminary test results on EUV photoresists have demonstrated similar trend. Compared to untreated photoresist, the LER/LWR power spectral density (PSD) data showed more than a half decade improvement in both the mid-frequency and low-frequency range. The significant low-frequency improvement affords this technique a unique advantage over other competing approaches. Pattern transfer of the LER/LWR improvements has been successfully demonstrated on 193/193i resists using both inorganic and organic ARC (anti-reflective coating).