YAG激光参量对刻蚀微坑形貌的影响

为了增加单次激光脉冲刻蚀微坑的深度,提高加工效率,利用双声光调制技术,通过对比不同能量密度的脉冲激光刻蚀微坑深度,及对比两种激光器输出的激光脉冲刻蚀微坑形貌,研究了激光参量对刻蚀微坑形貌的影响。结果表明,脉冲能量密度为20.21J/cm2时,刻蚀微坑深度达到最大值,继续增加能量密度时,微坑深度将随之减小;相比于单腔激光器,双腔激光器刻蚀微坑深度从5μm增加至10μm,微坑直径从161μm降至134μm。     

基于157nm深紫外激光的蓝宝石基片微加工

为了探索157nm深紫外激光对蓝宝石材料的微加工技术,采用157nm激光微加工系统,对蓝宝石基片进行了扫描刻蚀和打孔加工,以研究激光工艺参量与刻蚀深度、表面形貌的关系,分析了157nm深紫外激光对蓝宝石材料的作用机理,并利用扫描刻蚀法在蓝宝石基片上加工了一个2维图形。由实验结果可知,157nm深紫外激光作用于蓝宝石材料是一个光化学作用与光热作用并存的加工过程,适合扫描刻蚀的加工参量为能量密度3.2J/cm2,重复频率10Hz～20Hz,扫描速率0.15mm/min;在能量密度2.5J/cm2下的刻蚀率为0.039μm/pulse。结果表明,通过对激光重复频率和扫描速度的控制可实现蓝宝石材料的精细微加工。     

355nm紫外激光抛光Al2O3陶瓷工艺的研究

紫外激光抛光Al2O3陶瓷可以有效地降低加工中的热影响区、防止微裂纹的产生。为了得到不同激光工艺参量（激光能量密度、扫描速率、扫描间隔）对Al2O3陶瓷抛光表面粗糙度的影响规律,采用单因素实验方法进行了355nm紫外激光抛光Al2O3陶瓷的工艺实验,获得了最优的工艺参量范围。结果表明,当激光能量密度为6J/cm2、扫描间隔为2μm、扫描速率为60mm/s时,抛光后分别获得了较小的表面粗糙度值。这一结果对获得的低粗糙度、高质量的Al2O3陶瓷抛光表面具有指导意义。     

激光去除光纤涂敷层的实验研究

采用波长为10. 6μm的TEA CO2 红外激光和波长为248nm的KrF准分子激光去除SMF28光纤涂敷层,研究了激光脉冲能量密度和脉冲数与涂敷层去除效果之间的关系。实验 证明,涂敷层去除厚度随激光脉冲能量密度的增加呈对数增长,随红外激光脉冲数的增加呈对数变化,随紫外激光脉冲数的增加呈线性变化,且去除效果在红外激光8.15J / cm2、20个脉冲和紫外激光452mJ / cm2、800个脉冲下达到最佳。     

纳秒光纤激光诱导等离子体沉积铜的研究

为了实现玻璃表面的金属化，运用激光诱导等离子体沉积技术，选用廉价易维护且波长为1064nm的红外纳秒光纤激光和T2铜靶材，在透明材料普通硅酸盐玻璃表面直接沉积出了金属铜，并对其进行了光学显微镜和扫描电镜表征。结果表明，在一定的激光能量密度范围内（沉积阈值能量密度12.50J/cm2~激光器所能达到的最大能量密度27.13J/cm2），随着激光能量密度的增加，沉积在玻璃表面的铜颗粒数量增加；而在激光能量密度一定（27.13J/cm2）的条件下，若保持激光光斑的横向和纵向搭接率一致，当光斑搭接率不小于50%时，由于玻璃对激光的强烈吸收，导致铜沉积失败；当光斑搭接率在-20%~50%变化时，沉积在玻璃表面的铜颗粒数量呈现先增加后减小的变化趋势。激光诱导等离子体沉积技术是一种可实现透明衬底材料表面金属化的便捷技术。     

激光诱导化学反应刻蚀石英玻璃的实验研究

针对目前常用的超短脉冲激光加工、激光诱导等离子加工、纳秒紫外激光加工石英玻璃刻蚀率低下的问题,提出一种能够大范围、高刻蚀率、低裂损刻蚀石英玻璃的新方法,即利用1064nm红外激光诱导Ba(OH)2化学反应刻蚀。本文主要从不同能量密度激光诱导化学反应刻蚀机理进行分析,实验表明,当激光能量密度超过16 J/cm2时,石英玻璃被刻蚀;当激光能量密度在16~24 J/cm2之间时,仅物理作用去蚀石英玻璃,故刻蚀率随激光能量变化较小;当激光能量密度在24~42 J/cm2之间时,刻蚀率随激光能量密度变化较大,该阶段Ba(OH)2以及其分解生成的BaO在高温条件下都与石英玻璃主要成分SiO2发生化学反应并生成BaSiO3,故刻蚀率较高;激光能量密度在42~46 J/cm2时,化学反应速率趋于饱和,故该阶段刻蚀率随激光能量密度变化较小。     

激光清洗2A12铝合金复合漆层的技术研究

采用脉冲激光器对2A12铝合金基体表面涂覆的环氧树脂底漆与丙烯酸聚氨酯面漆进行激光清洗试验,针对激光清洗表面的形貌、粗糙度及元素含量进行分析。结果表明：在激光能量密度和激光扫描速度分别为4.45 J/cm²和8 mm/s时,能完全去除面漆且底漆保留完好,并获得了最接近底漆层原始厚度的残余漆层;在此激光能量密度下,当激光扫描速度为5.5 mm/s时,能完全去除复合漆层,且此时阳极氧化膜层的微观形貌完好,氧元素质量分数约为40%,清洗表面的粗糙度R_a=1.138μm。当参数组合为3.56 J/cm²和6 mm/s时,也能完全去除面漆且底漆保留较好;当激光能量密度为4 J/cm²和激光扫描速度为5 mm/s时,能完全去除复合漆层,此时阳极氧化膜表面上氧元素的质量分数约为34%。本研究证明了通过选择合适的激光工艺参数组合能够调控激光清洗质量,验证了激光分层清洗的可行性。     

激光对羟基磷酸铜的还原机理研究

为了研究激光选区金属化技术中，激光与尖晶石型化合物的相互作用机理，选用质优价廉、具有尖晶石结构的可见光和近红外光敏催化物质羟基磷酸铜(Cu₂(OH)PO₄)作为研究对象，利用X射线光电子能谱技术，探讨了波长为1064nm纳秒脉冲光纤激光、连续光纤激光和波长为355nm的纳秒脉冲紫外激光与羟基磷酸铜的相互作用机理。结果表明，3种激光都能将羟基磷酸铜中的+2价铜元素(Cu2+)还原为+1价铜元素(Cu+)，但还原过程随激光功率(0.13W~3.89W)或激光能量密度(2.76J/cm2~25.48J/cm2)的变化呈现不同的规律; 结合羟基磷酸铜的热性能分析和紫外可见光吸收光谱分析，初步判断，在上述还原过程中，可能同时存在光热反应和光化学反应。该研究为羟基磷酸铜作为一种新型的激光活性物质提供了理论基础。     

飞秒激光烧蚀齿面表层构态分析及其控制研究

为了分析飞秒激光烧蚀面齿轮齿面表层构成及其形态影响,本文针对面齿轮材料18Cr2Ni4WA,通过建立双温传热模型,模型采用向后有限差分法进行飞秒激光烧蚀数值模拟,研究飞秒激光烧蚀齿面的加工过程,分析能量密度对重铸层和热影响层的影响规律。结果显示:能量密度由173J/cm2增加至433J/cm2,重铸层厚度从068μm增加到102μm,热影响层厚度从096μm增加到135μm。针对重铸层的控制,本文实施了对面齿轮齿面的二次加工,实验结果表明:采用能量密度173J/cm2对齿面进行二次加工,加工后的齿面几乎没有重铸物残留,齿面平均粗糙度由0365μm降到了0185μm,有效地改善了面齿轮的加工质量,为提高飞秒激光精微烧蚀面齿轮精度提供了有益参考。     

组织表面附着水膜层对脉冲CO_2激光骨硬组织消融的影响

评估组织表面附着水膜层对激光骨硬组织消融效果的影响。以新鲜离体牛胫骨组织为实验样品,置于速度为12 mm/s的一维电动平移台上,分别在有附着和无附着水膜层情况下使用脉冲CO2激光进行垂直照射,来回扫描5次。激光波长10.64μm,脉冲频率60 Hz,能量密度范围18~84 J/cm2,光斑直径400μm,水膜层厚度0.4 mm。辐照后,利用体视显微镜和扫描电镜(SEM)观察消融凹槽表面形貌改变和微结构变化,利用光学相干层析成像(OCT)技术测量消融凹槽深度。结果表明,组织表面附着水膜层可减少激光骨消融过程产生的碳化和热损伤,有利于清洁消融凹槽,且辐射曝光量为50 J/cm2和70 J/cm2时附着水膜层可提高消融速率。     

Process development and adhesion behavior of electroless copper on liquid crystal polymer (LCP) for electronic packaging application

Liquid crystal polymer (LCP) has potentially a very wide application as substrate material in electronic packaging applications because of its unique advantages. The work in this paper was performed to realize the metallization of LCP for the purpose of board fabrication, and to study the adhesion between deposited copper and LCP. A homogenous electroless plated copper layer on LCP with 4 to 5 /spl mu/m thickness was achieved, while it increased up to 40 /spl mu/m with the subsequent electroplating. The timescale of etching, deposit ion rate, and pH value were gradually changing during the plating process and the influences on copper layer quality were investigated. The adhesion force of the copper-LCP layer system was measured by a shear-off-method. Scanning electron microscopy (SEM) was used to check the surface morphology after etching and the interface after shearing on both the backside of the copper layer and the LCP side. The relationship between the shear-off adhesion of copper and the time of chemical etching before plating was examined, and the optimal etching time is discussed. Heat treatment after plating was used, and it was shown that this significantly improved the adhesion strength.     

Effects of nodule treatment of rolled copper on the mechanical properties of the flexible copper-clad laminate

Rolled copper foil of 18 μm thickness underwent nodule treatment via electro plating in a solution containing dissolved CuSO₄ and NiSO₄. The product formed on the surface of the copper foil varied from copper oxides to nickel compounds of the sphere type with increasing current density and plating time. The highest surface roughness and maximum peel strength of 680 gf/cm were obtained with the formation of nickel compounds at a current density of 1.5 A/dm² and plating time of 30 s. In addition, the fracture location varied according to the plating parameters and occurred at the interface between the polyimide film and adhesive layer at the condition of the maximum adhesion strength.     

MEMS THz滤波器的制作工艺

基于MEMS技术制作了太赫兹(THz)滤波器样品,研究了制作滤波器的工艺流程方案,其关键工艺技术包括硅深槽刻蚀技术、深槽结构的表面金属化技术、阳极键合和金-硅共晶键合技术。采用4μm的热氧化硅层作刻蚀掩膜,成功完成了800μm的深槽硅干法刻蚀;采用基片倾斜放置、多次离子束溅射和电镀加厚的方法完成了深槽结构的表面金属化,内部金属层厚度为3~5μm;用硅-玻璃阳极键合技术和金-硅共晶键合技术实现了三层结构、四面封闭的波导滤波器样品加工。测试结果表明,研制的滤波器样品中心频率138GHz,带宽15GHz,插损小于3dB。     

Effect of Surface Preparation on Mechanical Properties of Ni Contacts on Polycrystalline (Bi1?x Sb x )2(Te1?y Se y )3 Alloys

We present a comparison of different surface preparation techniques for hot-extruded (Bi_1?x Sb _x )₂(Te_1?y Se _y )₃ alloys prior to Ni plating and their consequences on adhesion. The surface preparation is carried out by a relatively fast and well-controlled electrochemical etching procedure that provides morphologies with homogeneous flat surfaces on a scale of tens of micrometers. This procedure is not optimal for Ni metallization since it does not ensure enough roughness on the surface. Applying wet chemical etching with hypochlorite and nitric acid after the electrochemical etching changes the morphology, and the surface roughness increases, as evidenced by scanning electron microscopy and atomic force microscopy. Tensile tests carried out on n-type and p-type 1-mm-thick specimens, covered with a 12-??m Ni layer followed by Sn-Pb soldered joints, confirm a significant improvement in the ultimate adhesion strength, with fracture occurring within the thermoelectric material. Use of this two-step surface treatment, after slicing and prior to metallization, leads to maximum adhesion strength of around 38?MPa for either type of thermoelectric material. These results are consistent with the morphological changes observed by scanning electron microscopy on the surface after chemical etching.     

玻璃基板上的微细图形形成技术

概述了平滑玻璃基板上的微细图形形成技术以及纳米多孔ZnO膜,弱酸性铅催化液和弱酸性乙酸铜镀铜液的开发,可以在玻璃/ZnO中间层化学镀铜层/乙酸铜镀铜层/硫酸铜镀铜层上采用减成法形成L/S=100μm/100μm的微细铜电路图形。