Removal of Ar⁺ beam‐induced damaged layers from polyimide surfaces with argon gas cluster ion beams

Abstract

a An Ar Gas Cluster Ion Beam (GCIB) has been shown to remove previous Ar + ion beam-induced surface damage to a bulk polyimide (PI) film. After removal of the damaged layer with a GCIB sputter source, XPS measurements show minor changes to the carbon, nitrogen and oxygen atomic concentrations relative to the original elemental bulk concentrations. The GCIB sputter depth profiles showed that there is a linear relationship between the Ar + ion beam voltage within the range from 0.5 to 4.0 keV and the dose of argon cluster ions required to remove the damaged layer. The rate of recovery of the original PI atomic composition as a function of GCIB sputtering is similar for carbon, nitrogen and oxygen, indicating that there was no preferential sputtering for these elements. The XPS chemical state analysis of the N 1s spectra after GCIB sputtering revealed a 17% damage ratio of altered nitrogen chemical state species. Further optimization of the GCIB sputtering conditions should lead to lower nitrogen damage ratios with the elemental concentrations closer to those of bulk PI.

Argon Cluster Sputtering Source for ToF-SIMS Depth Profiling of Insulating Materials: High Sputter Rate and Accurate Interfacial Information

“…+ and 6 Li + signals were observed. More seriously, a sudden anomalous drop of Li + signals was observed at a depth of~2500 nm as shown in Figure 2.…”

“…Coupons (~10 × 10 × 1 mm 3 ) were cut from the bars and both sides of the coupons were polished. To study the diffusion behavior of Li, the SON68 coupons (natural isotopic abundance for all elements) were submerged in a solution of a dimethyl sulfoxide (DMSO) with dissolved LiCl ( 6 Li enriched, 6 Li: 7 Li = 95:5). The coupons were in contact with the solution at 150°C for 10 d. When the coupons were removed from the vessel, they were rinsed with clean DMSO, water, then ethanol, and dried in an oven.…”

“…Since argon cluster (Ar n + ) ion sources were implemented in SIMS [4,5] and subsequently used in X-ray photoelectron spectroscopy (XPS) [6] and ultraviolet photoelectron spectroscopy (UPS) [7], it has been widely applied for the molecular depth profiling of polymers, biological molecules, and other organic materials because they can retain molecular information during the erosion process. In addition, they can provide high sputtering rate, allowing the fast depth profiling of above soft materials [8][9][10][11][12][13][14][15].…”

Surface Analysis of Organic Materials with Polyatomic Primary Ion Sources

“…Finally, cluster ion beams can be utilized to recover molecular signal from previously ion beam-damaged regions. 24,48,49 This ability has particular implications for analysis of focused ion beam (FIB) cross sections that are created by a high energy Ga ion beam for subsequent analysis of buried structures within a sample. FIB sectioning is commonly used for secondary electron microscopy (SEM) and transmission electron microscopy (TEM) imaging.…”

Applications of Ar Gas Cluster Ion Beam to Oxide Thin Films

“…C 60 ion sputtering has been used for low damage surface cleaning and depth profiling of many organic materials, but the depth profiling of organic has not been successful because of a composition change due to preferential sputtering as well as degradation of chemical states of C 1s, N 1s, and O1s [3]. Recently, Ar GCIB has attracted a lot of attention as a promising method for depth profiling of organic thin films due to extremely low degradation of surface during depth profiling [4,5]. The effects of an Ar GCIB sputtering process on the structural and chemical properties of an organic material as well as the energy level alignment at the interface between the organic semiconductor and the electrode were studied.…”