Paper AS-ThP2
Measuring the Damage Depth and Recovery of PEMA Thin Films using Multiple Technique Analysis

Thursday, October 25, 2018, 6:00 pm, Room Hall B

Sputtering polymer surfaces with monatomic Ar ions is known to induce changes in the polymer chemistry. PEMA in particular, is a "self-sealing" polymer type which means during Ar⁺ sputtering cross-linking occurs. The advantage of using Ar cluster ions is that such chemical changes are not induced. It has also been demonstrated that Ar⁺_n ions can be used to remove the damage layer produced by Ar⁺ ions, thus recovering the surface chemistry. In this investigation this ability to recover the polymer surface is used to measure the relative thickness of the damage layer produced by Ar⁺ ions. To facilitate this other techniques were used for film thickness measurement and calibration. AFM was used to accurately measure the thickness of the PEMA film, this data was then used to calibrate a separate scale that was used to estimate the thickness based on the colour of the surface. As the colour of the surface is dependent only on the refractive index of the material, the angle of incidence of the incoming light and the thickness of the film, the measurements can produce a high accuracy thickness estimate to within ± 10 nm. The estimate of the original film thickness, made using the film colour, ~ 400 nm was in good agreement with the average thickness measured using AFM 398 nm.