CVD法制备铝化物涂层装置沉积室内前驱体流场仿真设计研究

为了制备均匀的CVD铝化物涂层,应保证沉积室内前驱气体的流场分布的均匀性.采用计算流体力学方法对沉积室内的前驱流体流场进行了仿真研究,对比了装备A、B、C型3种布风装置的CVD沉积室内流场的变化;对比了将初始进气口平均流速v经验提升至其1.5,2.0,2.5,5.0倍后沉积室内流场的变化.结果 表明:选择B型布风装置能令前驱气体均匀地从进气口流向沉积室内部,且被充分加热;前驱体的最大流速vmax在2.0v经验≤vmax＜2.5v经验时可保证气流分布、温度分布的均匀性.利用此结果,指导设计了CVD沉积室的布风装置,同时探讨了提升前驱体流速对气体流场均匀性的影响.     

动态流量法校准系统的蒙特卡罗分析

动态流量法校准系统的理论分析,对于提高真空规的校准精度、实际结构最佳参数的选择都具有十分重要的意义。通过对动态流量法校准系统中各误差因素的分析,指出蒙特卡罗法是目前一种比较全面的分析力法;并运用此法跟踪了大量气体分子的运动过程,比较真实地模拟了校准室球内分子流场的分布状况。从定量的角度,选择了真空规的校准区域,建立了校准室校准区域上的压力理论值与实际值之间的修正公式,为全面综合地进行误差分析奠定了基础。     

真空计量标准的研制与应用

兰州物理研究所研制了一系列真空标准装置,可用于真空规、方向规、分压力质谱计、真空漏孔和正压漏孔的校准.其静态膨胀法真空标准装置、动态流量法真空标准装置及超高/极高真空校准装置是用于真空规校准的三套基础标准,覆盖的校准范围为(10-10～105)Pa;程控式真空规校准装置适用于工业部门,其校准范围为(10-4～105)Pa;为实现质谱计的校准,研制了一台具有三路相同独立进样系统的分压力质谱计校准装置,标准分压力通过磁悬浮转子规以两种不同的方法进行测量,该校准装置可实现(10-7～10-1)Pa范围内的分压力校准;为实现真空漏孔的校准,研制了恒压式气体微流量标准装置和固定流导法气体微流量标准装置.恒压式气体微流量标准装置的校准范围为(10-8>～10-2)Pa·m3/s,同定流导法气体微流量标准装置的校准范围为(10-10～10-5)Pa·m3/s,漏孔漏率的校准通过比较被校漏孔和标准气体微流量计在一台四极质谱计上引起示漏气体离子流的大小计算得到;为实现正压漏孔的校准,研制了一台正压漏孔校准装置,采用定容法和定量气体动态比较法对正压漏孔进行校准,校准范围为(5 × 10-5～10-1)Pa·m3/s;研制了一台定向流真空校准装置,实现对方向规的校准和非平衡态分子流的研究,装置的校准范围为(10-7～10-1)Pa.     

用视角系数法计算球形比对容器中的分子流分布

本文介绍利用视角系数法对我们所建造的相对比对真空校准系统内的分子流场的分析计算过程;研究了系统内气流分布状态和限流膜孔大小的关系;定量考察了非均匀因素造成的影响;探讨了该系统作为精确真空规比对校准系统的条件。此外,还解决了两种特殊类型的视角系数的求解方法。     

基于临界流喷嘴动态气体稀释装置校准方法研究

介绍了临界流喷嘴动态气体稀释装置结构组成和工作原理。为解决其溯源要求,搭建了以气体活塞标准器为核心的校准系统,分别对稀释装置的组分通道和载气通道喷嘴(喷嘴组)流量值进行了校准,计算出稀释装置的稀释比并与原厂数据进行了对比。通过对流量校准结果的不确定度分析,最后给出了稀释装置稀释比的不确定度。     

恒流装置校准活塞气体流量计的方法研究

针对干活塞气体流量计连续测量瞬时流量采用的间断工作方式会造成较大的流场阻力波动,为消除阻力波动对干活塞气体流量计准确校准的影响,研究两种恒流法(体积管气体流量标准装置配合调压阀、皂膜气体流量标准装置传递恒流泵)的校准方法,得到满意的干活塞气体流量计校准结果。恒流泵传递比较法把皂膜气体流量标准装置和干活塞气体流量计在量值溯源图上联系起来,是对气体小流量量值溯源体系的有效补充。     

动态真空系统中气流状态的评价参数

在动态真空系统中,气体状态具有非均匀性及各向异性,此时若仍用压力等平衡态概念来描述气体状态,显然是不准确的。根据视角系数法的基本理论和计算结果,定义了真空系统中抽气性能评价多数,以及空间环模设备模拟宇宙空间分子沉的能力评价参数.通过对同心球系统中分子流场的具体分析,闸述了两个参数的物理意义。并用两个实例对α和β参数的应用作了更进一步的说明。     

一种(10~5～10~(-8))Pa真空计校准装置的设计

针对(10~5～10~(-8))Pa复合型真空计的一次性校准需求,设计出相应的校准装置。装置主要由校准室、真空测量模块、抽气与供气模块、标准气体流量计、烘烤模块等部分组成。设计的校准室为球形容器,通过串联分子泵组和离子泵抽气,在校准室中获得10~(-9) Pa量级的极限真空度。真空计的校准通过静态比较法、动态比较法及标准流量法实现,静态比较法采用电容薄膜真空计作为参考标准实现(10~5～10~(-1))Pa的校准范围;动态比较法用磁悬浮转子真空计作为参考标准实现(10~(-1)～10~(-4))Pa的校准范围;标准气体流量法采用(10~(-5)～10~(-9))Pa·m~3/s的标准气体流量计提供标准气体流量,实现(10~(-4)～10~(-8))Pa的校准范围。本文设计的校准装置范围为(10~5～10~(-8))Pa,合成标准不确定度估计为0.9%～2.3%,解决了对宽量程真空计的一次性校准技术问题。     

气体微流量标准装置的研制

气体微流量标准是校准气体微流量的一种装置，可用于传递型和应用型参考漏孔及气体微流量计的校准。它由恒压式微流量计、流量校准系统、待校流量引入系统和测量与控制系统四部分组成。恒压式微流量计的变容室采用了活塞液压驱动波纹管结构，活塞的平动由恒力矩测速电机驱动导轨平动机构完成，活塞的位移用精密光栅尺测量。在流量测量过程中，测量与控制系统将变容室和参考室之间的压力差控制在工作压力值的0．01％之内。该标准装置可采用直接测量法和比较测量法对气体微流量进行校准，其量程为1．71～1．22×10－5PaL／S，不确定度＜2％。     

动态气流下真空腔室内的压强分布及压差测量

集成电路(IC)装备工艺腔室内流场的均匀性是影响镀膜质量的关键因素。本文通过控制真空腔室入口处N_2流量(140,230,320 mL/min(标准状态))和出气口处压强值(36,45,55 Pa)来设置实验,采用压力管法测量低压腔室内任一点的压强值和薄膜规直接测量腔壁、出气口的压强值来实现腔室内压强分布的研究和压差的测量。讨论了腔壁与出气口之间的压差对压力管法的测量误差的影响;选择了二级匀气装置对进入腔室内的气体进行布气,通过比较腔室内同一水平面上各点与出气口之间的压差是否恒定来分析二级匀气盘的匀气效果。试验研究发现:在距离腔室中心150 mm的范围内,二级匀气装置的布气效果明显;本文采用的压力管法测量腔室内压强的误差与腔室进气量和腔室内流速存在内在联系。研究结果对IC装备设计及工艺控制有一定的指导意义。     

固定流导法校准真空漏孔方法研究

固定流导法采用的是分压力测量技术,对质谱分析室的漏放气率的指标要求不高.通过实验得到四极质谱计的非线性引起的测量误差可达38%,在具体校准过程中能够很好调节稳压室中的气体压力,使通过小孔的气体流量与待校真空漏孔漏率非常接近,从而避免了四极质谱计的非线性影响.稳压室中的气体压力比较大,所以稳压室不需要特别严格的材料处理工艺,具体校准过程中也不需要彻底的烘烤出气就能得到纯净的单一气体.固定流导法校准真空漏孔的不确定度的评定值为2.6%,可以通过精确校准电容薄膜规和控制温度来进一步降低漏孔校准的不确定度.     

Dynamic extension - A new principle for a vacuum primary standard for UHV-range (10-10 Pa) calibration of hot cathode ionisation gauges

The main obstacle in the construction of primary vacuum standards for very low pressures - ultra-high vacuum (UHV) - is outgassing from the walls of the apparatus. Thus, principles utilising a higher pumping rate in the calibration chamber, e.g., the pressure ratio technique, seem to be more useful for this range. However, a serious problem is inherent in this method, namely, that the gas in the calibration chamber is not in equilibrium and thus cannot be characterised by a single scalar pressure value, although such a value is then used to evaluate the measurement. This discrepancy can be overcome by using a hot cathode ionisation gauge as a transfer standard calibrated by the dynamic extension method.The dynamic extension method is explained and compared with the pressure ratio technique. The basic conditions for achieving acceptable uncertainty values are considered.     

The gas flux distribution in the XHV chamber of the vacuum primary standard developed by PTB

The ultimate pressure in the XHV calibration chamber of the PTB primary standard CE3, whose operation is based on the continuous expansion of gas, has been reduced by the use of a relatively large orifice area. Thus, the gas density and flux distributions cannot be taken as uniform in the calibration chamber. To eliminate this drawback we examined the gas flux distribution by Direct Simulation using the Monte Carlo method. This paper describes the gas flux distribution over the chamber walls, which was simulated, recorded and related to the idealized conditions. This allows determining the gauge position correction factor K_gi for each of the gauge ports. Using these factors, it is possible to eliminate the systematic deviation of the gas flow parameters from those under the idealized Maxwellian conditions and to improve the uncertainty budget.     

Digitaler Gasdosierer im Grobvakuumbereich

Digital gas dosing device for rough vacuum Vacuum gauges are calibrated by comparing the gauge under calibration with a reference gauge. Both gauges are mounted at a vacuum chamber. Different pressures are generated in sequence, and at each pressure the readings of both gauges are recorded. In the coarse vacuum range, the pressures are usually generated by successive injection of gas into the chamber via a manually operated dosing valve. This procedure requires some time and also fatigues the operator's hand. Therefore, a digital gas dosing device based on electromagnetic valves was developed, which allows a faster und more precise pressure generation than the analogue dosing valve and which is also friendly to the operators hand. Dosing device and its usage are described.     

双通道医用输液泵自动校准系统开发

针对医用输液泵人工校准过程中存在的工作效率低、检测精度低、温度偏差与数据无法批量处理等问题,提出了一个基于间接式流量法的输液泵自动校准方案。通过实验标定特定玻璃管段的体积获得累计流量体积,对输液泵进行自动校准时通过测量注满所标定体积的时间得到累计时间,两者的比值即输液泵的平均流量。由此设计了一套双通道医用输液泵自动校准系统,可以对测量结果进行误差和重复性分析及不确定度评定并给出校准报告。验证实验表明,自动校准系统的相对误差可达到2%以内,满足相关规范5%的要求。该系统可重复测量同一输液泵在不同流量时的准确度,也可利用双通道同时对多个输液泵进行流量校准测试,以及校准输液泵的阻塞报警情况。     

Theoretical design of calibration beams for strain gauge factor measuring apparatus

By starting with theoretical analysis and combining with the needs of practical applications, this article carries out a preliminary theoretical investigation of optimum design of the cross sectional shape and dimensions of calibration beams for strain gauge factor measuring apparatus. A new formula is derived in this paper that shows the quantitative relationship among strains on the beam surfaces, the strain non-uniformity within a certain range of the beam and beam thickness, which provides a theoretical basis for the accuracy improvement of the measuring apparatus and for correct application of the calibration beams, and also for drawing up and improving items concerning with calibration beams in strain gauge standards internationally. It is proven through experiments that the neutral axis of the bent calibration beam of rectangular cross section under pure bending moments is actually not circular but parabolic.     

The extension of the calibration of a mass spectrometer into the ultrahigh vacuum region

This paper describes how a mass spectrometer head and ion current amplifier system which has been calibrated as a partial pressure gauge in the high vacuum region, may have that calibration extended so that it can be used in the ultrahigh vacuum region. The technique is based on the measurement of the isotope ratio of the calibration gas. The paper also reports on the application of this technique to a particular instrument.     

The effect of ambient temperature on the sensitivity of hot-cathode ionization gauges

We measured the sensitivities of five hot-cathode ionization gauges for ambient laboratory temperatures between 23 and 31 °C. All of the ionization gauges exhibited very similar behavior, and the sensitivity could be adequately modeled with a linear function of temperature. The slopes of the fits were smaller than one would expect due to changes in the calibration chamber number density. The thermal transpiration effect, due to local heating of the gauge structures, can account for this, and a characteristic gauge tube temperature can be inferred from the temperature dependence of the sensitivity. A recent comparison of the high vacuum standards of several National Metrology Institutes (NMIs) was performed over the range of 10⁻⁶-10⁻³ Pa using hot-cathode and spinning rotor gauges as transfer standards. Among the participants, laboratory temperatures varied by as much as 5 °C. It is necessary to know how laboratory temperature affects the sensitivity of the hot-cathode transfer standards (spinning rotor gauges explicitly account for the gas temperature) so that individual laboratory results can be corrected to a common temperature.     

湿膜厚度规校准装置研究

分析了湿膜厚度规在建筑、喷涂等行业的应用技术要求,提出了一套实用并满足技术要求的校准装置设计方案,最后给出了误差源分析和校准结果的不确定度估算.     

一种臭氧老化试验箱内臭氧气体浓度校准方法的研究

提出了一种臭氧老化试验箱臭氧气体浓度的校准方法,并对臭氧浓度示值误差进行了不确定度评定。通过实验验证了被校臭氧老化箱内臭氧浓度示值误差小于±10%,臭氧浓度位置偏差小于20%,臭氧浓度波动度小于±10%。有效解决了臭氧老化试验箱内臭氧浓度的量值溯源问题,提高了该设备试验的准确性。