Bulk etch rates of CR-39 at high etchant concentrations:diffusionlimited etching

Systematic CR-39 bulk etching experiments were conducted over a wide range of concentrations(2–30 N)of NaOH-based etchant.Critical analysis and a deep discussion of the results are presented.A comprehensive nuclear track chemical etching data bank was developed.Three regimes of CR-39 bulk etching were identified.Regime I spans etchant concentrations from 2 to 12 N.Regime II spans concentrations from 12 to 25 N.We call this the dynamic bulk etching regime.Regime III is for concentrations greater than 25 N.In this regime,the bulk etch rate is saturated with respect to the etchant concentration.This classification is discussed and explained.The role of ethanol in NaOH-based etchants is explored and discussed.A parameter called the “reduced bulk etch rate” is defined here,which helps in analyzing the dependence of bulk etching on the amount of ethanol in the etchant.The bulk etch rate shows a natural logarithmic dependence on the density of ethanol in the etchant.

Bulk Etch Rate of LR 115 Polymeric Radon Detector

In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.

Measure the Bulk Etch Rate Using the Time-Diameter Method

The present work measured the bulk etch rate (VB?) of solid state nuclear track detector by taking the diameter time measurement of alpha particle in CR-39 detector. The values of the track diameter have been found by using TRACK-TEST program from Yu et al. function and Brun et al. function with different energies of alpha particles. The results showed that the time-diameter (t-d) method gave good results of the bulk etch rate (VB?) and these values were (1.705 and 1.72) μm·hr-1. They showed good agreement with the values measured by using the other methods, and it was a simple method because it required getting diameters of the tracks in the detector with the etching time.

背腔刻蚀型横向激励薄膜体声波谐振器制备技术研究

随着移动通信技术的快速发展,薄膜体声波滤波器逐渐向高频和大带宽方向发展。该文研究了POI(LiNbO_(3)/SiO_(2)/Si)基片上背腔刻蚀型横向激励薄膜体声波谐振器制作工艺,通过研究POI基IDT光刻、背腔硅刻蚀等工艺,确定了IDT层曝光量和背腔刻蚀等关键工艺参数。研制出的背腔刻蚀型横向激励薄膜体声波谐振器,其谐振频率为4565 MHz,反谐振频率为5035 MHz,机电耦合系数为20.86%。此制备工艺对研究高频、大带宽薄膜体声波滤波器具有重要的参考意义。

薄膜体声波滤波器的离子束刻蚀修频工艺

薄膜体声波滤波器因设计模型与器件性能存在匹配度问题及制造过程中各工序的累计误差导致频率一致性差,严重影响了产品良率,因此实现晶圆级别的频率修整十分必要。介绍了离子束刻蚀工艺的原理、技术特点与优势,研究了刻蚀电压、刻蚀电流、刻蚀距离、Ar气体体积流量及单次刻蚀量对刻蚀效果的影响,表征了离子束刻蚀工艺对AlN钝化层厚度均一性、刻蚀精度及粗糙度的影响。探究了离子束刻蚀工艺在薄膜体声波滤波器频率修整上的应用,表征了离子束刻蚀工艺对钝化层的表面形貌及晶圆应力的影响。研究结果表明,刻蚀电压为1500 V、刻蚀电流为18 mA、刻蚀气体体积流量为4 cm^(3)/min、刻蚀距离为80 mm时,刻蚀精度高,具有一定借鉴意义;通过3轮电性能测试分析和离子束刻蚀工艺,频率标准差仅为1.23 MHz,大幅提升了薄膜体声波滤波器的频率一致性。

Micro-track structure analysis for 100 MeV Si ions in CR-39 by using atomic force microscopy

To analyze the micro-track structure of heavy ions in a polymer material, parameters including bulk etch rate, track etch rate, etch rate ratio, and track core size were measured. The pieces of CR-39 were exposed to 100 MeV Si ions with normal incidence and were etched in 6.25N NaOH solution at 70 ℃. Bulk etch rate was read out by a profilemeter after several hours of etching. The other parameters were obtained by using an atomic force microscope （AFM） after a short time of etching. We have measured the second etch pits and minute etch pits to obtain the track growth curve and three dimension track structures to track the core size and etch rate measurements. The local dose of the track core was calculated by the δ-ray theory. In our study, we figure out that the bulk etch rate Vb=（1.58±0.022） μm/h, the track etch rate Vt=（2.90±0.529） μ/h, the etch rate ratio V=1.84±0.031, and the track core radii r≈4.65 nm. In the meantime, we find that the micro-track development violates the traditional track-growth model. For this reason, a scenario is carried out to provide an explanation.

聚丙烯核孔膜化学蚀刻工艺研究

探讨了蚀刻剂中重铬酸钾浓度、硫酸浓度及蚀刻温度、蚀刻时间等因素对聚丙烯膜基体蚀刻速率的影响 ;建立了基体蚀刻速率与重铬酸钾浓度、硫酸浓度、蚀刻温度的数学关联式 ;并选择一定的蚀刻条件对辐照过的聚丙烯膜进行蚀刻 ,得到了预期孔径的聚丙烯核孔膜。

PET核孔膜蚀刻速率影响因素的研究

核孔膜是通过重离子照射薄膜后进行化学蚀刻所得到的高性能过滤材料,蚀刻速率是影响高质量核孔膜制备的重要因素。本文探讨了不同蚀刻液浓度、温度以及重离子辐照能量对蚀刻速率的影响。利用140 MeV的32S离子在室温和真空条件下对4层堆叠的PET(polyethylene terephthalate)薄膜进行了辐照。在对辐照样品进行化学蚀刻期间采用电导法确定了径迹蚀刻速率Vt。结果表明:蚀刻速率与蚀刻温度呈指数相关,随蚀刻液浓度增加而线性增大;径迹蚀刻速率随能量损失率(离子能损)增大。研究确定,在入射32S能量为1.6 MeV·u-1时,NaOH浓度为1mol·L-1、蚀刻温度为85°C时最有利于形成圆柱形微孔。

高锰酸钾溶液对核径迹敏化新现象的研究

利用电导法研究高锰酸钾溶液预处理对聚对苯二甲酸乙二酯膜(PET)蚀刻速率的影响,用不同浓度的高锰酸钾溶液预处理1 h、2 h、3 h、4 h、5 h、6 h,径迹蚀刻速率在2 h时达到峰值,之后随预处理时间的增长而下降,基体蚀刻速率随预处理时间的增长而变小,半锥角随预处理时间增长而减小。在0.1 mol·L-1高锰酸钾溶液中分别加入5%、15%、25%、35%的2 mol·L-1硫酸溶液,实验结果表明,酸性高锰酸钾对径迹蚀刻速率影响较小,基体蚀刻速率随硫酸量的增加而变大,半锥角也相应地增大。另外,电导法中所用的直流电压大小对径迹蚀刻速率也有影响。

Energy calibration of a CR-39 nuclear-track detector irradiated by charged particles

Charged particle diagnosis is an important aspect of laser–plasma experiments conducted at super-intense laser facilities. In recent years, Columbia Resin #39 (CR- 39) detectors have been widely employed for detecting charged particles in laser–plasma experiments. This is because the CR-39 polymer does not respond to electromagnetic pulses or X-rays. This study presents a method for calibrating the relationship between particle energy and track diameter in a CR-39 detector (TasTrak■) using 3-8 MeV protons, 6-30 MeV carbon ions, and 1–5 MeV alpha particles. The particle tracks were compared under the manufacturer’s recommended etching conditions of 6.25 mol/l NaOH at 98℃ and under the widely adopted experimental conditions of 6.25 mol/l NaOH at 70℃. The results show that if the NaOH solution concentration is 6.25 mol/l, then the temperature of 70℃is more suitable for etching proton tracks than 98℃ and employing a temperature of 98 ℃ to etch alpha-particle and carbon-ion tracks can significantly reduce the etching time. Moreover, this result implies that C3+ ion or alpha-particle tracks can be distinguished from proton tracks with energy above 3 MeV by controlling the etching time. This calibration method for the CR-39 detector can be applied to the diagnosis of reaction products in laser–plasma experiments.

薄膜体声波滤波器AlN压电薄膜的ICP刻蚀研究

随着5G通信技术的发展,通信频段不断提高,以氮化铝(AlN)为压电薄膜材料的薄膜体声波滤波器作为目前唯一可集成的射频前段滤波器成为研究热点之一。本文开展AlN材料刻蚀工艺的实验研究,实验中采用光刻胶作为刻蚀掩膜,Cl2/BCl3作为刻蚀工艺气体,通过一系列工艺影响参数调整及相应刻蚀结果分析,获得了ICP源功率、RF偏压功率、腔体压强和BCl3气体流量对AlN材料和光刻胶掩膜刻蚀速率、刻蚀形貌的影响规律。通过综合优化工艺参数,最终得到了侧壁平坦、表面光滑的空气隙型薄膜体声波滤波器三明治结构。