Trace anion determination in concentrated hydrofluoric acid solutions by two-dimensional ion chromatography I. Matrix elimination by ion-exclusion chromatography

Since years, ion exclusion chromatography (ICE) has been the standard method to separate strong acid analyte anions from concentrated weak acid matrices such as hydrofluoric acid (HF). In this work, the commercially available IonPac ICE-AS 1 column was used to separate trace levels of chloride, nitrate, sulfate and phosphate from HF solutions at 20% (w/w). The efficiency of the separation was studied in more detail using techniques such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS). For 20% (w/w) HF solutions and at a water carrier flow-rate of 0.50 ml/min, the cut window was set from 8.5 to 14.5 min. Under these conditions, analyte recoveries of better than 90% were obtained for chloride, nitrate and sulfate, but only about 75% for phosphate. The HF rejection efficiency was better than 99.9%. It was found that the ICP techniques, measuring total element levels and not species, yielded significantly higher recoveries for phosphorus and sulfur compared to IC. Evidence will be given that part of the added phosphorus (approximately 15% for an addition of 10 mg PO4/kg) is present as mono-fluorophosphoric acid (H2FPO3). In the case of sulfate, the difference between IC and ICP-MS could be attributed to an important matrix effect from the residual HF concentration.     

Trace anion determination in concentrated hydrofluoric acid solutions by two-dimensional ion chromatography II. Method performance study with a hydroxide eluent and a low noise suppressor

The two-dimensional ion exclusion chromatography/ion chromatography (ICE-IC) approach is considered to be the method of choice for the determination of trace anions in concentrated hydrofluoric acid (48-50%, w/w). In order to achieve lower detection limits, this method was for the first time used with electrolytically generated and purified hydroxide eluents in combination with a low noise electrochemical suppressor. Compared to carbonate based eluents, the achieved gain in peak height sensitivity for chloride, sulfate, nitrate and phosphate is a factor of 6, 7, 16 and 13, respectively. The instrumental detection limits, based on the background noise, are 2, 0.2, 0.4 and 1.4 microg/kg HF 50% (w/w) for the same anions. Their method detection limits, calculated according to SEMI, are all within the 6-10microg/kg HF 50% (w/w) range and thus at least 10 times lower than the current Tier C grade requirements. The chromatographic run time could be shortened with some 10 min by the use of a relatively fast high-capacity hydroxide selective anion exchange column.     

基于SEMI标准的集成电路制造装备控制系统设计

随着集成电路制造装备的复杂度越来越高,设计一个符合SEMI标准的集成电路制造装置控制系统显得尤为重要。针对SEMI标准的要求,提出了一种控制系统的结构设计方法。设计的系统定义了SEMI标准中规定的控制模型与状态模型及其他操作,能够满足实际控制需要与SEMI标准的要求。     

大角度离子注入机控制系统软件设计

大角度离子注入机的控制系统具有控制部件和控制算法复杂、支持SEMI自动化软件标准等特点,通过优化软件结构和关键控制算法,成功实现控制系统设计和GEM标准组件设计,测试证明软件自动化程度高、稳定、可靠。     

SEMI与春天相约盛会与激情干杯

进入2004年的中国半导体产业以其高速发展的成就,再次成为全球半导体产业的亮点,SEMICON China 2004 在上海顺利召开。为了向半导体行业全程报道此次盛会,也为了展示中国半导体产业蓬勃发展的良好趋势,作为SEMICONChina 2004合作宣传媒体的《半导体技术》杂志,再次隆重推出“SEMI观察”栏目。让业界了解SEMICON China,沟通信息创造商机。     

半导体及IC设备不锈钢表面技术研究

介绍了半导体及IC产业设备之关键不锈钢零部件的表面处理工艺方法,重点叙述了国外200 mm(8英寸)以上半导体及IC工艺设备为了避免特殊环境的腐蚀和颗粒的产生而采用的最为先进的表面处理EP工艺技术,诠释了半导体及IC产业设备零部件超高纯(UHP)技术指标要素,另外对我国目前半导体及IC行业的表面处理现状进行了研究和分析,并提出了努力方向。     

Systematic Investigations of Plastic Vials Concerning Their Suitability for Ultratrace Anion Analysis in High-Purity Industrial Applications

Ultratrace anion analysis in high-purity industrial applications is done using commercially available plastic vials to store the eluted liquid samples. Plastic vials are manufactured with materials containing several additives. Such additives might potentially release anionic contaminants, thus degrading the blank quality and determination limits (DL). The durability and thermal stability of several materials was found to be a function of anionic species. Fluorinated materials showed the best results for the majority of anions with the exception of fluoride. For the selective analysis of fluoride, polypropylene was found to be the best vial material, together with glass. Cold water extraction showed better results compared to hot water extraction. Over a long observation period, hot water extraction did not at all improve the performance, indicating that this type of supposedly efficient cleaning of the plastic containers to render them less prone to contaminant release does not hold true.     

控制信号传输的高可靠性设计

在我们平常使用或设计的电子电路中,或多或少都会受到电磁干扰的影响。