Atmospheric Pressure Ionization Mass Spectrometry and Its Application in the Analysis of Ultra High Purity Gases: A Review
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摘要:
超高纯气体在工业生产中有非常重要的地位, 如半导体工业中电子气的质量直接影响半导体器件的性能, 百万分之几的微量杂质气体便可导致集成电路中元件存储信息量的减少。越来越高的气体纯度要求对分析方法及仪器的灵敏度提出了很大的挑战。大气压电离质谱(APIMS)由于可以在大气压条件下对杂质进行电离, 并伴随高效的电离方式, 因此具有极高的灵敏度, 成为超高纯气体杂质分析中极为有效的技术手段, 特别适合检测10-9 mol/mol甚至10-12 mol/mol浓度量级的气体杂质。APIMS采用电晕放电及63Ni两种电离源, 通常以电晕放电电离源为主, 质量分析器常采用四极杆, 同时为适应超高纯气体分析, APIMS配备了气体进样系统及可将标准气体稀释产生校正气体的稀释系统。APIMS对杂质检测的灵敏度与杂质的电离方式密切相关, 电荷传递是杂质电离最主要的一种方式, 适用于电离能相差较大的底气与杂质, 常见的N2、Ar由于电离能较高, 其中的大部分杂质均可依靠该方式测定; 质子转移反应的应用通常与H2有关, 常用于H2中杂质的测定, 也可以通过添加H2的方法促进对Ar中N2杂质的检测; 运用形成团簇离子的反应尽管较少, 但亦有报道, 通过监测团簇离子O2+·H2O, 可提高O2中杂质H2O的检测灵敏度。依据不同的电离反应, 可以设计对不同杂质的测定方式, 实现对痕量、超痕量杂质的检测。APIMS检测灵敏度通常比电子轰击电离质谱(EI/MS)高104~106倍, 因此目前依然是超高纯气体分析中不可替代的仪器方法, 但在某些方面如对有腐蚀性电子特气的分析, 方法灵敏度有待提高。
Abstract:Ultra high purity (UHP) gases are very important in the manufacturing industry. As an example, in the semiconductor industry, the quality of electron gas directly affects the performance of semiconductor devices; a few parts per million of trace impurities in gases can reduce component store information in integrated circuits. Thus, challenges to the sensitivity of the analytical instruments and the analysis methods arise for detection of ultra-trace impurities. Atmospheric Pressure Ionization Mass Spectrometry (APIMS), which could ionize impurities under the atmospheric pressure conditions with high efficiency of ionization and sensitivity, becomes the most important instrument for the purity analysis of the UHP gases. APIMS is especially suitable for the analysis of trace impurities with a concentration below 10-9 mol/mol or even 10-12 mol/mol. Two ionization sources based on corona discharge and 63Ni have been developed for APIMS, where the former is more commonly equipped. Quadruple rod is usually used as the mass filter. A sampling and dilution system, in which the components in standard gas can be diluted to far lower concentrations for calibration, is utilized in APIMS for analysis of UHP gases. The detection sensitivity of impurities of APIMS is quite suitable to the ionization modes. One of the main modes is charge transfer reaction, which is applicable to matrix and impurities with large different ionization energy. For example, most impurities in Ar and N2 can be determined by this mode due to the high ionization energy of Ar and N2. And by adding H2, APIMS is also used for detecting N2 in Ar. The third mode is the reaction of forming cluster ions, for which few applications have been reported. The mode could enhance the detection sensitivity of H2O in matrix O2 by detecting the ion of O2+·H2O. Based on these ionization modes, various detecting methods for different impurities can be designed to effectively detect trace or ultra-trace impurities. The sensitivity of APIMS is usually 104-106 times higher than Electron Impact-Mass Spectrometry. As a result, APIMS is still irreplaceable in UHP gas analysis however, methods such as those required for the analysis of corrosive electronic special gases, should see an improvement in the sensitivity.
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[1] [2] Caroll D I, Wernlund R F, Cohen M J. Apparatus and methods employing ion-molecule reactions in batch analysis of volatile materials: United States, 3639757 [P/OL]. 1972.
[3] doi: 10.1021/ac200918u
[4] [5] doi: 10.1039/c1ja10158g
[6] [7] [8] [9] [10] [11] doi: 10.1021/ac102687u
[12] [13] Bossard P, Mettes J, Gornick F, Breziner L. Novel sensor for measuring trace impurities in ultra pure hydrogen; proceedings of the 2012 AIChE Annual Meeting, Pittsburgh, PA, F, 2012 [C].
[14] [15] [16] [17] Juneja H S. Removal of Adsorbed Moisture and Organics from Surfaces and Nanostructures in Semiconductor Manufacturing [D]. Tucson: The University of Arizona, 2008.
[18] doi: 10.1021/ac00254a016
[19] doi: 10.1021/ac50059a027
[20] doi: 10.1021/ac60328a035
[21] doi: 10.1021/ac60342a009
[22] doi: 10.1021/ac50006a035
[23] doi: 10.1021/ac00178a014
[24] Siefering K, Berger H. Improved apims methods. 1. Analysis of nonstandard contaminants in nitrogen and argon[J]. Journal of The Electrochemical Society, 1992, 139(5): 1442-1445.
[25] [26] Bandy A R, Ridgeway R G, Mitchell G M. Negative ion atmospheric pressure ionization and selected ion mass spectrometry using a 63ni electron source, US 6, 956, 206 B2 [P/OL]. 2005.
[27] doi: 10.1021/ac971273o
[28] [29] doi: 10.1021/ac50010a023
[30] [31] doi: 10.1149/1.2055146
[32] doi: 10.1143/JJAP.34.4991
[33] doi: 10.1143/JJAP.34.359
[34] [35] [36] [37] doi: 10.1143/JJAP.32.2886
[38] doi: 10.1265/ehpm.2000.97
[39] [40] -
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