Richard D. Kaplan

Conducting polyanilines: Discharge layers for electron‐beam lithography

This paper describes the use of electrically conducting polyanilines as discharge layers for electron‐beam (e‐beam) lithography. The emeraldine oxidation state polyaniline is a soluble material which can be doped by various cationic reagents, most commonly protonic acids, to afford conductivity on the order of 10° Ω−1 cm−1. The conducting polyanilines are incorporated as thin interlayers (2000 A) in a multilayer resist system consisting of a planarizing underlayer (2.8 μm) and the imaging resist (1.2 μm) on top. We find that various acid‐treated polyanilines eliminate charging during e‐beam patterning of the resist, i.e., zero pattern displacements are observed as compared to the case where a conducting interlayer is not incorporated into the resist system. In the latter case placement errors greater than 5 μm are observed as a result of charging. A minimum conductivity of 10−4 Ω−1 cm−1 is required for the polyaniline interlayers in order to observe zero pattern displacement. In addition, we have simplifi...

In-Situ Radiation Induced Doping

Abstract In this paper we describe a novel method of inducing conductivity in polyaniline photochemically or by electron-beam exposure. This is accomplished with the use of onium salts which are a class of materials that decompose upon irradiation generating protonic acids. We find that the onium salt may be blended with the polyaniline and upon irradiation, the generated acid acts as an in situ dopant for the polymer. Conductivity on the order of ⋍0.1 S/cm has been attained. This system has significant applications in lithography since it allows patterns of conducting lines to be generated. The polyaniline/onium system represents the first electrically conducting photo and electron-beam resist. In addition, we find that this radiation induced doping technique is applicable to polythiophene systems as well.

Diffusion and Defect Structure in Nitrogen Implanted Silicon

Nitrogen diffusion and defect structure were investigated after medium to high dose nitrogen implantation and anneal. 11 keV N 2 + was implanted into silicon at doses ranging from 2×10 14 to 2×10 15 cm −2 . The samples were annealed with an RTA system from 750°C to 900°C in a nitrogen atmosphere or at 1000°C in an oxidizing ambient. Nitrogen profiles were obtained by SIMS, and cross-section TEM was done on selected samples. TOF-SIMS was carried out in the oxidized samples. For lower doses, most of the nitrogen diffuses out of silicon into the silicon/oxide interface as expected. For the highest dose, a significant portion of the nitrogen still remains in silicon even after the highest thermal budget. This is attributed to the finite capacity of the silicon/oxide interface to trap nitrogen. When the interface gets saturated by nitrogen atoms, nitrogen in silicon can not escape into the interface. Implant doses above 7×10 14 create continuous amorphous layers from the surface. For the 2×10 15 case, there is residual amorphous silicon at the surface even after a 750°C 2 min anneal. After the 900°C 2 min anneal, the silicon fully recrystallizes leaving behind stacking faults at the surface and residual end of range damage.

Integration of Photo-Patternable Low-κ Material into Advanced Cu Back-End-Of-The-Line

We report herein the demonstration of a simple, low-cost Cu back-end-of-the-line (BEOL) dual-damascene integration using a novel photo-patternable low-κ dielectric material concept that dramatically reduces Cu BEOL integration complexity. This κ=2.7 photo-patternable low-κ material is based on the SiCOH-based material platform and has sub-200 nm resolution capability with 248 nm optical lithography. Cu/photo-patternable low-κ dual-damascene integration at 45 nm node BEOL fatwire levels has been demonstrated with very high electrical yields using the current manufacturing infrastructure. The photo-patternable low-κ concept is, therefore, a promising technology for highly efficient semiconductor Cu BEOL manufacturing.