Heterogeneous polymer coatings, such as those used in organic electronics and medical devices, are of increasing industrial importance. In order to advance the development of these types of systems, analytical techniques are required which are able to determine the elemental and molecular spatial distributions, on a nanometer scale, with very high detection efficiency and sensitivity. The goal of this study was to investigate the suitability of laser postionization secondary neutral mass spectrometry (Laser-SNMS) with a 157 nm postionization laser beam to image structured polymer mixtures and compare the results with time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements using Bi primary ions. The results showed that Laser-SNMS is better suited than ToF-SIMS for unambiguous detection and submicrometer imaging of the wide range of polymers investigated. The data also showed that Laser-SNMS has the advantage of being much more sensitive (in general higher by more than an order of magnitude and peaking at up to 3 orders of magnitude) than ToF-SIMS while also showing superior performance on topographically complex structured insulating surfaces, due to significantly reduced field effects and a higher dynamic range as compared to ToF-SIMS. It is concluded that Laser-SNMS is a powerful complementary technique to ToF-SIMS for the analysis of heterogeneous polymers and other complex structured organic mixtures, providing submicrometer resolution and high sensitivity.

In this study, tendencies of ionization and cleavage processes of time-of-flight (TOF)-SIMS were examined using MS/MS, which enables an easy qualitative analysis of organic matters, to clarify the fragment ions showing structures of the organic materials. In this paper, a result of reviewing fragment ions in TOF-SIMS spectra for polystyrene (PS) as the representative material is shown. Samples were measured with collision induced dissociation (CID)-MS/MS of 1200 L (Varian Inc., USA) and TOF-SIMS J105 (Ionoptika Ltd, UK) for the examination of fragment ions of the PS in TOF-SIMS spectra. The use of CID MS/MS with a wide range of energy distribution is effective for the study of the ionization and cleavage process of TOF-SIMS. As a result, the fragment ions representing the PS structure were clarified, which is useful for the material definition. The qualitative analysis was also applied to the fragment ions particularly obtained in this examination. It is suggested that the examination of the fragmentation process using MS/MS is useful for the mass spectra analysis of organic materials in TOF-SIMS.

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The damage of polymer surfaces caused by the high energy primary ion beams of TOF-SIMS was examined using Ar cluster ions. Polymer damage, the damage of secondary ions detected from the polystyrene surface and the damage layer formed by the Bi 3 primary ion beam have previously been studied. In this study, the damage observed in the secondary ions was studied by using Ar cluster primary ions. The secondary ions were mainly classified into two types, ions reflecting the polystyrene structure and cyclized ions, generated by excessive energy, which are not useful for qualitative analysis. The layer damaged by irradiation of the Bi 3 primary ion regarding PS samples was confirmed using Ar cluster sputtering beams. The depth of the layer that has chemical damage in the PS main chain caused by 30 kV Bi 3 ++ (ion dose: 5 × 10 12 ions/cm 2 ) irradiation was approximately 50-60 nm. The Ar cluster ion sputter rate in PS decreases with the Bi 3 ion irradiation. Micro PS particles that are not able to be detected by a conventional TOF-SIMS measurement can be effectively analyzed by accumulating the secondary ions over the static limit using Ar cluster sputtering.

A bucket-type ion source for ion milling applications has been investigated. Experiments showed that uniformity of the ion beam profile is subject to the cusp field. In order to extract uniform and well-collimated ion beams, operating conditions were optimized for 500 eV argon beam extraction. Current density (0.55 mA/cm) was constant within ±5% over the center of an 8 cm diam in a 10 cm acceleration system. Uniformity of milling rate for Cr–Cu–Cr film (520 Å/min) was constant within ±6% over a 7.6 cm wafer without substrate rotation. Micrographs of the etched patterns were studied. It was concluded that a bucket-type ion source is suitable for ion milling applications, especially large-area ion milling systems.