Moore's Law compliance necessitates the use of high dielectric constant (k) (e.g. Hf, Ti, Zr, Ta) and low-k (e.g. silane chemistries) material thin films in place of traditional Si/SiO2 films. Chemical precursors of these films require characterization of trace-level impurities to avoid device failure. The reporting limits listed on precursor Certificates of Analysis require analytical methods such as inductively coupled plasma - mass spectrometry (ICP-MS) ion chromatography (IC) and gas chromatography - mass spectrometry (GC-MS), for determination of trace elements, chloride and precursor purity, respectively. Analytical challenges associated with characterizing these materials include precursor volatility, air and moisture sensitivity, parent element ICP-MS matrix effects and ICP-MS elemental and molecular interferences. In addition, sample preparation methods preceding the analyses must decompose the sample yet preserve the integrity and quantity of the analytes present in the original samples. This paper will describe analytical methods designed to meet these analytical challenges.
Logic boards were failing at Enhanced Mac Minus One (EMMO) test or Integrated Circuit Test (ICT) after printed circuit board (PCB) rework. The failure to boot was originally traced to a suspected bad microcontroller chip. Replacing this chip, or an oscillator tied to the microcontroller circuit, did not consistently solve the boot problem. With further testing, it was found the microcontroller circuit was very sensitive to resistance and was essentially shorted.A resistor in the microcontroller circuit was identified on the flip side of the PCB. Several areas on the board, including the resistor R161, were seen to have a slight white haze/ low gloss appearance on the surface of the PCB. To test if the residue was electrically conductive, five boards were selected whose sole failure was R161. The resistance of the individual resistors was measured with a digital multimeter (DMM). The resistor was then cleaned with isopropyl alcohol and a cotton swab. Each board was retested at ICT and the individual resistors measured again with a DMM. Cleaning the area surrounding the resistor with isopropyl alcohol, corrected the failure four of the times.
A flow injection inductively coupled plasma magnetic sector mass spectrometry (FI-ICP-MS) method was developed for the analysis of Cd, Cu, Ni, Zn, and Mn in estuarine waters. The method uses just greater than 3 ml sample, and employs an automated on-line preconcentration step using a metal chelating resin (Toyopearl AF-Chelate 650 M). Acidified samples for the analysis of Cd, Cu, Ni, and Zn were buffered on-line to pH of 5.6 ± 0.2 with ammonia acetate just prior to loading onto the chelating resin, while samples for Mn analysis were adjusted to pH of 9.0 ± 0.2 prior to concentration. Limits of detection were: Cd = 1.4 ng l −1 (0.013 nM), Cu = 17 ng l −1 (0.27 nM), Ni = 28 ng l −1 (0.48 nM), Zn = 46 ng l −1 (0.70 nM), and Mn = 86 ng l −1 (1.6 nM). The blank concentrations were less than 1.5% of the SLEW-2 concentrations for each element analyzed, except Ni, which had a significant, but very constant blank from the Ni cones used. The detection limits were less than 5% of the concentrations observed in the San Francisco Bay estuarine samples, with the exception of Zn where the detection limit was 10% of the concentration of lowest San Francisco Bay sample analyzed. Using the FI preconcentration technique, we conducted medium resolution scans of potential isobaric interferences (mass units 55-66) using a magnetic sector ICP-MS to identify a number of interferent complications with evaluating certain isotopes, especially, 59 Co, and 60 Ni. Investigations of potential interferents illustrate the importance of appropriate isotope selection and, in some instances, the need to perform blank corrections with both an instrumental and a matrix blank. The method was verified by the analysis of an estuarine water standard reference materials (SLEW-2), and San Francisco Bay samples with previously reported values. Six estuarine samples run in triplicate generated the following average precision (presented as % R.S.D.); Cd = 4.2%, Cu = 3.2%, Ni = 3.3%, Zn = 4.4%, and Mn = 2.2%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.