激光背面湿式刻蚀蓝宝石过程的数值模拟与实验研究

发布时间：2018-05-22 20:31

本文选题：激光背面湿式刻蚀 + 蓝宝石　；参考：《广东工业大学》2015年硕士论文

【摘要】：蓝宝石具有高耐磨性、高硬度、高脆性和化学性能稳定等特点,广泛的应用在工业及国防领域,其作为蓝光LED (Light-Emitting Diode)最主要产业化衬底、智能手机的面板、耐磨轴承材料和窗口材料。由于蓝宝石的这些物理特性,使得传统的金刚石加工方法难以加工,并存在崩边、破裂和刀具磨损等问题。相比而言,激光背面湿式刻蚀是一种具有很大发展前景的加工方法,尤其是对加工透明材料如蓝宝石、石英、玻璃等。激光背面湿式刻蚀过程是一个复杂的物理过程,涉及相变,对流换热等,同时激光加工过程是个瞬态过程,实验很难进行检测,而数值模型方法为这种瞬态过程提供解决方法。本文实验选用CuSO4为工作液体,采用1064nm激光背面湿式刻蚀蓝宝石基片。首先,总结了激光背面湿式刻蚀技术的研究意义和国内外的研究现状；其次,理论分析激光诱导液体相沉积机理,研究激光背面湿式刻蚀过程中热效应,并结合实验分析沉积层形成机理,研究蓝宝石材料去除机理以及刻槽形成的过程；再次,采用有限元方法对激光背面湿式刻蚀蓝宝石材料去除过程进行数值模拟,分析激光脉冲作用下温度场的瞬态分布以及激光参数(扫描次数、扫描速度和能量密度)对刻蚀尺寸(刻槽深度和宽度)的影响,并进行实验验证,主要研究方法和结论如下：1.首先通过使用CuSO4为工作液体进行激光背面湿式刻蚀蓝宝石基片实验,在蓝宝石基片的背面沿着激光的扫描方向会形成沉积层,厚度约为2μm；采用XPS、俄歇分析方法得到沉积层的主要成分为氧化亚铜和氧化铜,结合激光诱导液相沉积机理,推导出沉积层产生的光化学反应方程式。2.激光背面湿式刻蚀蓝宝石基片过程中发现：激光背面湿式刻蚀蓝宝石基片,并不是扫描一次就能发生刻蚀。刻蚀初期,需要多次在同一位置重复扫描,材料表面改性后,刻蚀阈值降低后才能产生稳定刻蚀。分析刻槽表面的微观形貌认为：整个刻槽的形成过程存在点蚀--连续刻蚀的变化过程,点蚀现象导致蓝宝石基片背面变得更为粗糙,有利于沉积层在蓝宝石基片背面附着和后续去除材料。3.根据实验测定的沉积层的几何尺寸和沉积层的成分,基于三维热传导方程建立了激光与蓝宝石--沉积层--液层的多介质层相互作用物理模型,采用ANSYS对多介质层模型进行数值模拟分析,得到激光辐照作用蓝宝石的温度场分布,研究刻槽轮廓尺寸与激光刻蚀工艺参数(激光能量密度、扫描速度和扫描次数)之间的关系。模拟结果发现：整个温度云图依赖光斑能量密度变化呈高斯分布；随着激光脉冲数的增加,蓝宝石材料背面达到的最高温度也增加；热传导速度从高到低依次是沉积层、蓝宝石基片、溶液层；随着能量密度和扫描速度的降低,蓝宝石基片的刻蚀深度、宽度逐渐增加；在刻槽截面可以看到,沿着激光的扫描方向,刻槽的底部出现等间距的波纹起伏,扫描速度的越小,这种现象越明显。4.为了验证理论模型的合理性和可靠性,进行了激光背面湿式刻蚀工艺实验,结果发现：当激光能量密度达到26.5J/cm2,蓝宝石材料发生熔化刻蚀；随着激光能量密度的增加,刻蚀深度和宽度均增加；随着扫描速度的减小,刻蚀深度和宽度增加；随着扫描次数的增加,刻蚀深度和宽度均增加。这些变化规律与数值模拟结果相符合。刻槽的断面轮廓图与数值模拟的刻槽的截面的基本形状和尺寸(深度和宽度)基本一致；在刻槽底部出现波浪起伏特征与实验结果一致,说明建立的激光湿式刻蚀的多介质层模型的一定有效性和可靠性。
[Abstract]:The laser back wet etching is a complicated physical process , especially for processing transparent materials such as sapphire , quartz , glass and so on . In contrast , the laser back wet etching is a complicated physical process , which involves phase change , convection heat transfer and so on . In contrast , the laser back wet etching is a complicated physical process , which involves phase change , convection heat transfer and so on .
Secondly , the mechanism of laser induced liquid phase deposition is analyzed , and the thermal effect of laser back wet etching is studied .
The effects of laser parameters ( scanning times , scanning speed and energy density ) on etching size ( groove depth and width ) were analyzed by means of finite element method . The effects of laser parameters ( scanning times , scanning speed and energy density ) on etching size ( groove depth and width ) were analyzed .
On the basis of three - dimensional heat conduction equation , the physical model of multi - media layer interaction of laser and sapphire - sedimentary layer - liquid layer is established by using the XPS and Auger analysis methods .
As the number of laser pulses increases , the highest temperature on the back of the sapphire material increases .
the heat conduction speed is from high to low , in turn , a deposition layer , a sapphire substrate and a solution layer ;
With the decrease of energy density and scanning speed , the etching depth and width of sapphire substrate gradually increase ;
In order to verify the rationality and reliability of the theoretical model , the laser back wet etching technology experiment was carried out to verify the rationality and reliability of the theoretical model .
With the increase of laser energy density , the etching depth and width increase ;
the etching depth and the width increase as the scanning speed is reduced ;
As the number of scans increases , the depth and width of the etching increase . These changes are in agreement with the results of numerical simulation . The profile of the notch is basically consistent with the basic shape and dimension ( depth and width ) of the groove of the numerical simulation .
The wave fluctuation characteristics at the bottom of the groove are consistent with the experimental results , which indicates the validity and reliability of the multi - media layer model of laser wet etching .
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN249;TN305.7

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