化学过滤器在半导体洁净室新风净化中的应用

在半导体行业,空气中的悬浮气态分子污染物对于制程的潜在危害越来越受到人们的重视。目前,在通风系统中使用化学过滤器是去除AMC的主要方法之一。结合工程实例,介绍了半导体行业在新风处理单元中加装化学过滤器的实际效果。     

空调用化学过滤器概述

本文介绍应用于系统的化学过滤器，包括化学过滤一般知识，控制室内环境化学污染的相关指标，现场检测方法和典型过滤器产品。     

晶片CMP后表面纳米颗粒的去除研究

对晶片化学机械抛光(CMP)后表面吸附的纳米颗粒去除进行了研究,分析了晶片表面吸附物的种类及吸附机理。由于晶片表面吸附的有机物多为大分子物质,它在晶片表面的吸附除了容易处理的物理吸附外,还会和晶片表面构成化学键,形成难以处理的化学吸附。对清洗过程中颗粒的去除有严重的影响,提出利用电化学清洗,结合表面活性剂和兆声波清洗的方法去除晶片表面的纳米颗粒。经金相显微镜观察和原子力显微镜检测,晶片表面纳米颗粒能得到很好地去除,效果明显优于单纯的兆声波清洗方法。     

一种CO2吸附剂胶体颗粒的研制

为去除密闭空间人员新陈代谢所产生的CO2,研制了一种化学吸附剂,通过对吸附剂配方和成型工艺的调整,观察了吸附性能的变化规律,实验结果表明:用19%的氢氧化锂,1.25%的聚乙烯醇,3.87%的羧甲基纤维素钠与200克水溶解烘干所制得的吸收剂,对CO2的化学吸附稳定、吸附时间长、最佳吸收效率可高达90%,适用于地下工程、潜艇等高密闭环境空间的空气净化。     

对氨基苯甲酸分子的化学吸附动力学研究

以表面增强喇曼散射做为实验手段,提出了研究固体表面化学吸附动力学的理论模型和实验方法。计算了对氨基苯甲酸在银表面的化学吸附动力学参数;多相因子,吸附以及脱附速率常数Ka和Ka,发现对氨基苯甲酸的吸附是多相的(m≈0.4),讨论了描述化学吸附时多相往性概念的的意义。结合SERS光谱分析结果,我们认为PABA化学吸附的多相性表示吸附分子在表面上存在不止一种吸附形式。     

多层铜布线表面CMP后颗粒去除研究

针对目前清洗技术存在的问题进行了详细分析,研究了微电子材料表面污染物的来源及其危害,并介绍了表面活性剂在颗粒去除方面的作用。研究了化学机械抛光(CMP)后Cu布线片表面的颗粒吸附状态,分析了铜片表面颗粒的吸附机理。采用非离子表面活性剂润湿擦洗方法,使Cu表面的颗粒处于易清洗的物理吸附状态。利用金相显微镜和原子力显微镜(AFM)在清洗前后进行对比分析,实验采用聚乙烯醇(PVA)刷子分别对铜片和铜布线片进行清洗,发现非离子界面活性剂能够有效去除化学机械抛光后表面吸附的杂质,达到了较好的清洗效果。     

多层Cu布线化学机械抛光后颗粒的去除问题

针对多层Cu布线化学机械抛光后去除表面吸附颗粒时难以解决的氧化腐蚀问题,分析了颗粒在抛光后Cu表面上存在的两种吸附状态即物理吸附和化学吸附。采用在清洗剂中加入非离子表面活性剂的方法,使Cu表面的颗粒处于易清洗的物理吸附状态;为解决由于Cu在停止化学机械抛光后,具有高能的新加工表面被残留抛光液继续氧化和腐蚀,影响清洗效果的问题,采用在清洗剂中添加防蚀剂BTA的方法在Cu表面形成Cu-BTA单分子致密膜,有效控制了表面氧化和腐蚀。利用光学显微镜对采用不同清洗剂清洗过的Cu表面进行观察分析,发现在清洗剂中添加表面活性剂和防蚀剂BTA,不仅有效去除了表面沾污的颗粒,又保证了清洗后表面的完美与平整。     

CMP过程中纳米级颗粒在芯片表面吸附状态控制

化学机械全局平面化过程中各种颗粒的污染十分严重.随着时间增长,吸附状态由物理吸附转变为化学吸附最终形成键合.文章提出了一种优先吸附模型,是表面活性剂分子优先吸附在硅片表面,降低能量达到稳定不但可以有效控制颗粒在硅片表面的吸附状态,对已经吸附的颗粒可以起到解吸的作用.实验证明用表面活性剂对硅片进行处理,可以有效控制颗粒的吸附状态,对CMP清洗有重要作用.     

一种有效去除CMP后表面吸附杂质的新方法

CMP后大量颗粒吸附在芯片表面,根据颗粒在芯片表面的吸附状态,确立优先吸附模型.利用特选的表面活性剂优先吸附在芯片表面可以有效控制杂质的吸附状态,使之处于易于清洗的物理吸附.实验表明,特选的非离子界面活性剂能够有效去除CMP后表面吸附的杂质,达到较好的清洗效果.     

碱性多羟多胺螯合剂对Cu CMP后BTA去除作用及机理

苯并三唑(BTA)在微电子领域常被用于铜抛光液中的抗蚀剂,抛光后的BTA残留需要通过化学机械抛光(CMP)后清洗工序从晶圆表面去除,否则会影响器件的性能.通过实验研究了碱性多羟多胺类螯合剂对抛光后晶圆表面残留BTA的去除效果及机理.首先通过傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)研究了BTA在铜表面的吸附状态,发现铜表面的氧化程度会影响BTA在晶圆表面的吸附状态;然后采用体积分数为0.02％、pH值为10.3的碱性多羟多胺螯合剂去除铜表面BTA薄膜.FTIR和XPS测试结果显示,碱性多羟多胺螯合剂可以有效去除铜表面BTA薄膜;最后,通过实验数据研究了碱性多羟多胺螯合剂去除BTA的机理.     

The removal of airborne molecular contamination in cleanroom using PTFE and chemical filters

Cleanroom contamination and its impact on the performance of devices are beginning to be investigated due to the increasing sensitivity of the semiconductor manufacturing process to airborne molecular contamination (AMC). A clean bench was equipped with different filter modules and then most AMC in the cleanroom and in the clean bench was detected through air-sampling and wafer-sampling experiments. Additionally, the effect of AMC on device performance was examined by electrical characterization. A combination of the NEUROFINE PTFE filter and chemical filters was found to control metal, organic, and inorganic contamination. We believe that the new combination of filters can be used to improve the manufacturing environment of devices, which are being continuously shrunk to the nanometer scale.     

洁净室气态分子污染物的监测技术

随着微电子工业工序复杂性的增加和产品尺寸的不断缩小,气态分子污染物(AMC)对产品的影响成为洁净室环境控制中重点关注的问题。文章介绍了洁净室中AMC的定义,重点阐述了AMC的监测技术。     

Synthesis of new artificial magnetic conductors for wideband applications

The use of an artificial magnetic conductor (AMC) has proved very effective to simultaneously enhance gain and reduce the thickness of planar antennas. Owing to the strong resonant nature of such metamaterials, low profile antennas based on periodic AMC exhibit poor performances in terms of bandwidth. Demonstrated is the use of a nonintuitive and automatic CAD tool to synthesise a thin partially reflected surface based on AMC (PRS-AMC) operating in a wide frequency band. The process of optimisation is carried out using a micro genetic algorithm (mGA) coupled to a `home made? 3D-TLM electromagnetic software implemented on a parallel computer.     

AMC-Based Transmission of Resource Allocation Messages for Short-Sized Packet Services

We introduce a scheme that applies adaptive modulation and coding (AMC) to the transmission of resource allocation messages, and show that the AMC transmission of control messages reduces control overhead and is particularly effective for services with small-sized packets, such as VoIP.     

多速率调制无线信道服务过程及信道建模

 现代无线网络中,为克服复杂无线信道对系统服务质量影响,自适应调制编码是采用于物理层的有效技术手段之一。该文采用队列技术分析无线信道服务过程与业务流过程和物理层自适应调制编码技术关系,对自适应调制编码无线信道服务过程建模;并提出一种基于服务过程突发特性等效的自适应调制编码无线信道建模方法。该文采用数值方法分析自适应调制编码无线信道服务过程所表现的突发性,验证了所提出无线信道建模方法的可行性和有效性。     

手持设备电源芯片的自动测试方案设计

为提高手持设备电源芯片的选型效率,提出了适合电源芯片的自动测试方案.通过分析手持设备各路电压的负载需求,筛选出电源芯片的测试项目;在分析传统电源芯片测试电路后,给出了软件和硬件电路的示意设计.基于LabVIEW平台,提出了同步数据采集、触发和存储功能的实现方案.AMC3100芯片的测试数据表明,既保证测试精度,测试效率又大幅提高.     

A software‐defined radio testbed for deep learning‐based automatic modulation classification

Automatic modulation classification (AMC) is the demodulation process on the receiver side, which is a crucial protocol for current and next‐generation intelligent communication systems. This method becomes complicated, in the presence of channel noise, to identify the modulation of the transmitted signal, that is, the transmitter and receiver with its ambiguous parameters like timing information, signal strength, phase offset, and carrier frequency. Two fundamental approaches are used for the AMC, namely, the signal statistical feature‐based approach and the maximum likelihood approach. Current Feature‐Based AMC approaches typically built for a limited set of modulation; a comprehensive AMC approach utilizing convolutional neural networks (CNN) is suggested in this article to overcome this obstacle. Altogether, 11 different types of modulations considered. In this method, without an extraction function, the transmitted signal can be identified directly. Also, the features of the received signal are known directly by using this method. The classification accuracy using CNN seems to be remarkable, especially for low SNRs. In this article, a realistic AMC framework that can be quickly applied to provide reliable efficiency in numerous commercial real‐time scenarios has developed and tested. Therefore, to prove the functional viability of our proposed model, it was applied to the software‐defined radio test‐bed.     

An enhanced channel-quality indication (CQI) reporting scheme for HSDPA systems

A major evolution of UMTS standard is the high speed downlink packet access (HSDPA). One of key techniques supporting HSDPA is the adaptive modulation and coding (AMC) in which the modulation scheme and the coding rate are adaptively changed according to the downlink channel quality reported by the user equipment (UE). Therefore, the channel quality indication (CQI) reporting scheme is directly related to the accuracy of AMC and the performance of HSDPA. This letter proposes an enhanced CQI reporting scheme that can be used when a proportional fair scheduling algorithm (PFA) is used as a packet scheduling algorithm. The proposed scheme uses a dynamic threshold to filter off redundant CQI reports. With the proposed scheme, the battery capacity of UK can be conserved, maintaining the performance of traditional CQI reporting scheme.     

空气传播分子污染物、源头及监控系统的研究

通过研究某半导体制造工厂应用AMC控制程序的案例,探讨关于AMC控制的具体内容,了解AMC并掌握如何制定正确的AMC评估战略、描述与建立AMC控制原则和规范、理解AMC控制系统的设计理念。     

基于DBN 的频率与相位编码信号快速调制识别方法

为提升低信噪比条件下雷达/ 通信频率、相位编码信号调制识别性能,降低特征提取复杂度,提出了基于深度信念网络DBN(Deep Belief Network, DBN)以及快速特征提取的调制识别方法。结合快速傅里叶累加算法FAM(FFT Accumulation Method)算法,提出了将循环谱估计图像转化为有效可识别特征向量的提取算法;设计了用于编码信号调制识别的DBN 网络训练与识别框架。仿真结果表明,文中方法较传统方法具有更低的特征提取与预处理复杂度,提取的特征在几种典型编码调制模式信号中具有明显区分,DBN 训练识别框架对雷达/ 通信编码信号调制识别均具有可行性与有效性,在低信噪比条件下对无线电编码信号有更高的识别正确率。