【作者】 刘霖；

【导师】 叶玉堂；

【作者基本信息】 电子科技大学 ， 光学工程， 2009， 博士

【摘要】 激光诱导液相腐蚀是利用激光在单色性、方向性、高亮度上的独特优势,以激光对材料的光子效应和热效应为基础,辅助材料的液相腐蚀进程,从而满足材料的刻蚀需要。激光诱导液相腐蚀与普通化学腐蚀相比,可以有效地消除晶体取向影响,制作出更加多样化的腐蚀图形；与激光诱导气相腐蚀相比,其工艺条件更加容易实现,操作更加简单；与干法离子刻蚀相比,对基片无离子损伤,过度腐蚀容易控制,成本低。正因如此,激光诱导液相腐蚀技术逐渐成为国内外学者研究的热点之一。因影响半导体激光诱导液相腐蚀效果的因素很多,要得到理想的腐蚀图样以及监控腐蚀进程有着很大的技术难度,至今没有得到有效解决。本文的工作就是围绕激光诱导液相腐蚀技术而开展的,主要的研究结果与创新之处如下：1)以激光诱导液相腐蚀技术为主线,以实现其应用为最终目的,深入开展基本原理、实时监测、加工工艺和器件应用四个层面的研究,搭建有效的激光诱导液相腐蚀研究体系。激光诱导液相腐蚀是典型的交叉学科技术,它以激光技术为基础,涉及到包括化学、材料等众多领域,知识背景复杂,使得现阶段激光诱导液相腐蚀的基本原理、加工工艺水平、实时监控以及实际应用等方面均存在急待解决的问题。因各个层面之间互相关联,独立研究很难达到推动实际应用的目的,本论文选择以搭建激光诱导液相腐蚀体系为切入点,开展广泛而深入的研究,成为本论文的主要特色之一。2)提出了利用红外热像实时监测,系统研究了激光诱导液相腐蚀进程中的腐蚀溶液的热环境分布、变化等特征,使温度这一影响激光诱导液相腐蚀的重要因素得以有效表征。温度是影响化学反应进程的重要因素之一。在激光诱导液相腐蚀的进程中,激光、化学反应热等因素均对反应的实际温度有很大的影响,加之热对流、热传导、热辐射等因素的存在,使得深入了解激光诱导液相腐蚀的热环境、分布特征成为难题。本论文提出利用红外热像实时监测,将温度差异引起的热辐射能转化为相应的红外可见图像,记录、储存并进行处理分析,获得需要的监测结果,并积极探索腐蚀进程、腐蚀速率、粗糙度等与红外热图像之间的内在联系。3)提出了获得材料反应启动时长(刻蚀材料与腐蚀溶液从开始接触到腐蚀开始的时间间隔)的测量方法,并对不同材料、不同腐蚀液浓度下的化学反应启动时长进行了实验研究,获得了有价值的实验结果。不断提高刻蚀速率,被普遍认为是湿法刻蚀技术持续发展的根本所在,因为,与干法刻蚀技术相比,只有不断提高刻蚀速率,才能克服横向腐蚀等缺陷,进一步突出其应用面广、成本低、选择腐蚀性能好等优势。随着刻蚀速率的不断提高,对时间的控制精度要求也越来越高,化学反应启动时长的存在,对快速刻蚀的时间控制而言,有着较大影响,已经不容忽视。但至今仍缺乏有效的技术手段对反应启动时长进行测定,往往对其进行大致估计或完全忽略,这一缺失,将最终制约快速刻蚀技术的进一步发展。本论文从化学反应过程伴随热生成这一现象,在对材料表面腐蚀液滴及腐蚀液膜红外辐射特性深入研究的基础上,利用红外热像实时监测系统,对竖直材料表面滑动液滴残留线形液膜进行红外灰度实时采集,从中成功获得了反应启动时长的相关信息。4)提出了包括抗蚀膜掩蔽法、次序选择腐蚀法、电极腐蚀法和两步腐蚀法在内的激光辅助液相腐蚀系列方法,并通过对加工方法的选择,实现了在不同材料刻蚀上的成功应用,取得了较理想的刻蚀效果。工艺技术研究是决定激光诱导液相腐蚀实际应用效果的关键环节之一。本论文以大量的实验研究为基础,并结合理论分析,最终建立了以抗蚀膜掩蔽法、次序选择腐蚀法、电极腐蚀法和两步腐蚀法为主的激光辅助液相腐蚀系列方法。抗蚀膜掩蔽法是在基片表面不需要腐蚀的区域用抗蚀膜覆盖,激光照射在无抗蚀膜区域,对基片进行腐蚀；电极腐蚀法是通过外加电压在溶液中形成腐蚀电流,促使中间离子产物脱离基片表面；次序选择腐蚀法是针对混合溶剂的使用先后顺序进行选择；两步腐蚀法是利用材料不同方向上刻蚀速度的差异,延长或缩短相应的刻蚀时间。在实际的刻蚀工艺中,可根据不同的需求,确定一种或多种工艺方法,本论文为阐述需要,对各种工艺进行独立分析。经理论分析和实验验证,以四种工艺为基础的系列方法,可以满足绝大多数刻蚀需要并取得较理想的刻蚀效果。5)以半导体激光诱导液相腐蚀技术为工艺基础,提出并设计了一种满足全方位自对准的圆孔型探测器；同样,以高温超导薄膜的激光诱导液相腐蚀工艺为基础,提出、设计、制作并测试了一种光控高温超导衰减器。激光诱导液相腐蚀在器件制作上的应用及其性能研究有着重要意义。本论文结合器件实际应用背景的需要,发挥激光诱导液相腐蚀技术的优势,提出了一种满足全方位自对准的圆孔型探测器,以及一种实现精确信号衰减的光控高温超导衰减器。据我所知,在国内、外文献中,均未见有关材料反应启动时长红外测量方法、液层下材料表面粗糙度表征、圆孔型探测器、激光腐蚀系统工艺方法、光控高温超导衰减器、激光化学腐蚀热环境监测等内容的报道。更多还原

【Abstract】 The unique superiority of laser such as monochromaticity, directivity and high brightness are used in Laser assisted wet chemical etching (LAWE). Taken the laser to the material photon effect and the thermal reaction as the foundation, this technology can assist in the material aqueous etching process,thus satisfies the need of material etching. There are the following advantages with LAWE technology. First, compared with general chemical etching, the influence of crystal orientation can be eliminated effectively and the diverser etched figure is manufactured by LAWE. Secondly, it’s much easier to realize the process conditions and simpler to operate than Laser introduced gaseous etching. Furthermore, compared with Dry ion etching, there is no ion damage to the substrate, the excessive etching is easier to control and the cost is low. So LAWE technology has become one of the world study focuses gradually. Because of many factors that influence the effect of the semiconductor Laser Aqueous Etching, it’s very difficult to obtain the ideal etched figure and monitor the etching process.So far these problems have not been solved.This dissertation focuses on the Laser induced aqueous etching technology. The main research results and important contributions are as follows:1)Mainly based on the LAWE technology, to realize its application, the principle, the process real-time monitoring,processing and device application are researched. The LAWE study system is established effectively.Based on laser technology, LAWE is a typical interdisciplinary. Its content ranges from chemistry to material and many other fields. With the complex background, many problems related to the practical application(involving principle,processing level and process monitoring) press for solution. Because every aspect mentioned above correlates.The establishment of LAWE system is an important starting point in the dissertation. The extensive and in-depth research covering a wide range and requiring strong innovative capacity is conducted.2) The infrared thermal imaging method is used in real-time monitoring. The thermal environment distribution of the etching solvent in the LAWE process is studied systematically. So the important factor temperature which affects LAWE is characterized.The temperature is an important consideration in the chemical reaction. In the LAWE process, laser, chemical reaction heat and other factors all have a great influence on practical temperature. Additionally, thermal convection, heat conduction and thermal radiation are also taken into account. Using infrared thermal imaging for the real-time monitoring is proposed by the article. Thermal radiation caused by the temperature difference is converted into infrared visible image. With recording and processing, required monitoring results are obtained. The interrelationships between the process, rate and the surface roughness of etching process and infrared thermal image are explored.3)The measuring method to obtain the material reaction starting time length(it takes a certain period time to react between the material and etching solution from contact to etching)is put forward. Focused on different materials and etching solution concentrations, the chemical reaction starting time lengths are researched and valuable experiment results are obtained.Constantly increasing the etching rate is generally considered as the foundation for the sustainable development of the wet-etching technology. Because compared with dry-etching technology, the defects including lateral etching can be overcome only by continuous acceleration of etching rate. Thus the advantages of wet etching:wide application scope, low cost and excellent selective etching property stand out. With the continuous improvment of etching rate, the high control accuracy of time is required. The chemical reaction starting time length has great impact on controlling the fast etching time. So far the effective technology to measure the reaction starting time length is lacked. A rough estimate or complete neglect are in most cases. So the further development of fast etching is slowed down. From the phenomenon that the heat generation in the chemical reaction, this thesis has made thorough research to the etching droplet on the surface of the material and infrared radiation character of the etching liquid membrane. The infrared thermal real-time monitoring system is used to collect the infrared grey image real-timely of the linearis liquid membrane caused by the sliding droplets on the vertical material surface. The information about the reaction starting time length is acquired successfully. 4) As one of the critical steps, study on processing technology determines the practical application results of LAWE.The laser-assisted aqueous etching processing system is proposed in this thesis including etch-resistant film masking method, oder-selective etching method, electrode etching method and two-step etching method. According to the selection of methods, the etching on the different materials are realized successfully. Ideal etching results are obtained.Etch-resistant film masking method:cover the substrate surface on which etching is not required with etch-resistant film. And laser irradiates to etch the region without the film.Electrode etching method:etching electric current is formed in the solution by applying electric voltage and causes the intermediate ion product to separate from the substrate surface. Oder-selective etching method focused on the using order of the mixed solvents. Two-step etching method takes advantages of the etching rate differences in the different direction of the materials to prolong or shorten the etching span.In the practical etching processing, one or more processing methods can be adopted for different demands. Various processing methods are analysed separately by this thesis. According to the theoretical analysis and experimental verification, the above four methods building the basic processing system can meet most etching need and gain ideal etching results.5) LAWE has the vital significance for the application of the device fabrication and its property’s research. Based on LAWE technology as the processing foundation, an omnidirectional self-aligned circular detector is designed and an optically controlled high-temperature superconducting attenuator(it can realize the accurate signal attenuation) is fabricated.As far as I know, It is first reported both in domestic and abroad such as measuring method to obtain the material reaction starting time length, the surface roughness of etching process, self-aligned circular detector, laser-assisted aqueous etching processing system, optically controlled high-temperature superconducting attenuator and thermal environment distribution monitoring of the etching solvent in the LAWE process更多还原