固结磨料研磨蓝宝石晶片的工艺优化

为了满足蓝宝石晶片高效低损伤的加工要求,采用亲水性固结磨料研磨垫研磨蓝宝石晶片的工艺,研究基体中碳化硅粒度尺寸、基体类型、金刚石粒度尺寸及研磨液中磨料4个因素对材料去除率和表面粗糙度的影响,并综合优化获得高加工效率和优表面质量的工艺参数。实验结果表明:基体中碳化硅粒度尺寸为10 μm、基体类型为Ⅱ、研磨垫采用F公司粒度尺寸为35~45 μm的金刚石、研磨液中磨料的粒度尺寸为5 μm的碳化硅为最优工艺组合,亲水性固结磨料研磨蓝宝石的材料去除率为431.2 nm/min,表面粗糙度值为R_a 0.140 2 μm。      

蓝宝石晶片纳米级超光滑表面加工技术研究

本文提出以蓝宝石塑性磨削和化学机械抛光为主要手段，以原子力显微镜为主要检测工具，来制备满足光电子领域要求的纳米级超光滑蓝宝石晶片的新方法。在高刚性磨床上，用W7的金刚石砂轮以f=1μm／r进给量，实现了蓝宝石晶片的浅损伤塑性域磨削。配制了以SiO2溶胶为抛光料的监宝石晶片专用抛光液，稳定地获得了无损伤层的RMS小于0.2nm的超光滑蓝宝石晶片表面。GaN外延生长所需蓝宝石晶片的合理抛光参数是：SiO2的粒子直径为7nm、浓度为3％、pH=11、压力P=200Pa。     

单晶蓝宝石高效超精密加工技术研究

针对光电子器件、集成电路等应用领域对单晶蓝宝石高质量的表面需求,而单晶蓝宝石自身的硬度和良好的化学稳定性给抛光带来较大的困难。文章在分析、对比直接采用2μm金刚石磨料化学机械抛光蓝宝石基片效果的基础上,提出机械研磨与化学机械抛光相结合的工艺抛光蓝宝石。结果表明,采用10μm的碳化硼磨料机械研磨蓝宝石,材料去除率为8.03μm/h,表面粗糙度Ra由1.18μm迅速降至22.326 nm;采用粒径为2μm和0.5μm的金刚石磨料化学机械抛光蓝宝石晶片,有效的去除机械抛光带来的损伤,最后表面粗糙度Ra可达0.55 nm。此抛光工艺能满足蓝宝石晶体高效、超光滑、低损伤的抛光要求。     

碳化硅晶体电化学机械抛光工艺研究

针对碳化硅晶体抛光效率低的问题,研究碳化硅晶体的电化学机械抛光工艺,对比NaOH、NaNO₃、H₃PO₄ 3种电解液电化学氧化碳化硅晶体的效果。选用0.6 mol/L的NaNO₃作为电化学机械抛光过程的电解液,使用金刚石–氧化铝混合磨粒,通过正交试验研究载荷、转速、电压、磨粒粒径对电化学机械抛光碳化硅晶体的表面质量和材料去除率的影响。采用优选的试验参数进行抛光试验,结果表明:在粗抛阶段可实现20.259 μm/h的高效材料去除,在精密抛光阶段可获得碳化硅表面粗糙度S_a为0.408 nm的光滑表面。      

陶瓷磨削的材料去除机理

磨削是目前工程陶瓷的主要加工方法,为了开发新的高效、低成本、低损伤加工陶瓷的方法,需要更深入地揭示其加工机理。本文介绍了陶瓷磨削的材料去除机理方法的研究进展,就其进行了一定的讨论,并得出相关的结论。     

双端面磨削磁钢用φ750毫米金刚石砂轮的应用试验

磁钢的磨削加工一直采用碳化硅砂轮在车磨床上单片、单面进行磨削,效率低、劳动强度大。采用M7675A磨床,用φ750毫米金刚石砂轮可同时磨削两个平面,工件精度、光洁度、磨削效率都得到较大提高,成本降低,实现了磁钢的高效率半自动磨削加工。     

紫外光催化辅助Ga面GaN化学机械抛光试验研究

目的 探究在紫外光催化辅助抛光过程中,相关因素对氮化镓晶片Ga面去除率(MRR)及表面粗糙度(Ra)的影响规律,提高单晶氮化镓高效率低损伤的超光滑表面质量。方法 通过结合紫外光与化学机械进行抛光,采用单因素试验方案,对GaN晶片的Ga面进行紫外光催化辅助化学机械抛光试验,比较在无光照、光照抛光盘、光照抛光液3种抛光方式和不同TiO₂浓度、pH值、H₂O₂含量、抛光压力、抛光盘转速和抛光液流条件下的抛光效果。最后通过正交试验进行抛光工艺参数优化,通过测量不同条件下紫外光催化辅助化学机械抛光过程中的MRR值和Ra值,探究GaN晶片Ga面抛光效果。结果在紫外光催化辅助抛光条件下,通过对单因素试验和正交试验的抛光参数进行分析和优化,GaN晶片材料去除率可以达到698.864nm/h,通过白光干涉仪观测可以获得表面粗糙度Ra值为0.430nm的亚纳米级超光滑GaN晶体表面。结论 基于紫外光催化辅助GaN晶片Ga面化学机械抛光试验,紫外光辅助化学机械的复合抛光方式能够促进GaN表面生成物Ga₂O₃     

YT2M-4826双面研磨机气动控制系统的设计

针对手机、平板电脑玻璃显示屏及太阳能电池晶片、红宝石等需求急增,迫切要求大量的高工艺、高精度、高效率的研磨抛光设备。根据传统产品存在精度差和效率低的缺陷,采用先进的压力传感器、PLC和气缸的控制技术,同时采用数字PID控制方法,实现轻压、自重、重压3种工艺的研磨抛光方式,解决了加工工件时易造成工件的破碎和难加工的问题。该方法运用在 YT2M-4826双面研磨机上,实现了研磨机的精密、平稳的研磨和抛光功能,更实现了研磨抛光工件的高精度和高效率加工。经深圳富士康公司使用,反映很好,完全达到设计和加工要求。     

纳米硬质合金磨削温度及热量分配比例试验研究

为了对纳米硬质合金磨削温度及热量分配比例进行深入研究,同时探讨不同粒度硬质合金间的差异,为多种粒度硬质合金的磨削加工及质量控制提供参考,选择以纳米硬质合金GU092为主的3种硬质合金进行磨削试验。结果表明：相比普通硬质合金,纳米硬质合金的磨削温度较低,热量分配比例较高,在2.5%～11.8%之间;磨削温度随晶粒度变细而降低,且细粒度材料表面的塑性变形小,磨削时消耗的能量更少;热量分配比例随着晶粒度的变细而增加,细粒度硬质合金的物理机械性能更强,导热性能更好。在考虑加工效率的前提下,适当降低磨削深度、增大进给速度,有助于降低温度、提高质量。     

微复制金刚石研磨片对玻璃加工质量的影响

利用固结式微复制金刚石研磨片(Trizact Diamond Tile,TDT)对不同玻璃进行减薄研磨,确定不同粒度金刚石TDT的磨削去除率;研究了研磨后的玻璃加工质量,测量了玻璃表面粗糙度及玻璃亚表面损伤层的状态。同时用9μm粒度碳化硅浆料做对比研磨试验。结果表明,同样粒度的金刚石TDT与传统的碳化硅浆料研磨相比可以得到更高的磨削去除率,减少玻璃亚表面损伤层,降低粗糙度。对于康宁玻璃,9μm粒度的TDT可以达到95μm/min的磨削去除率,是同粒度碳化硅浆料研磨的2倍多;Ra可以达到0.37μm,明显好于碳化硅浆料研磨;亚表面损伤也减轻很多。采用2μm粒度的TDT研磨后可获得Ra0.09μm、接近透明的表面。     

Relaxation of residual stresses in SiC wafers by annealing

Residual stresses in SiC wafers, which were introduced during production processes including sawing, lapping, mechanical polishing （MP）, and chemical-mechanical polishing （CMP）, were evaluated in terms of changes in radius of curvature and high-resolution X-ray diffractometer （HRXRD） measurements. It was found that annealing was an effective method to reduce stress fields and to improve the wafer flatness. Lapping process generated more residual stresses than other machining processes, and these stresses could be relaxed by thermal treatment. The results showed that annealing was an essential procedure following lapping in the whole production process. The molten KOH etching results accounted for the correlation between the relaxation of stresses and the creation of basal screw dislocations.     

Damage mechanisms during lapping and mechanical polishing CdZnTe wafers

CdZnTe wafers were machined by lapping and mechanical polishing processes, and their surface and subsurface damages were investigated.The surface damages are mainly induced by three-body abrasive wear and embedded abrasive wear during lapping process. A new damage type, which is induced by the indentation of embedded abrasives, is found in the subsurface. When a floss pad is used to replace the lapping plate during machining, the surface damage is mainly induced by two-body abrasive and three-body abrasive wear, and the effect of embed-ded abrasives on the surface is greatly weakened. Moreover, this new damage type nearly disappears on the subsurface.     

Ultra-thinning Processing of Dielectric Substrates by Precision Abrasive Machining

The ultra-thin dielectric substrate was obtained by precision grinding and lapping/polishing. In the precision grinding, the substrate was thinned until 50 μm in thickness using fine-grained diamond wheels and a polishing pad. The substrates in the lapping and polishing were thinned to 17 μm in thickness with good flatness. The good flatness was produced by hard polishing pad made of polyvinyl chloride resin owing to their mechanical properties of high fixed grain density. These were confirmed by detailed AFM observations. Finally, the substrates were segmentalized to produce five thousand small tips (2 mm × 0.4 mm) by a precision dicing device.     

合金薄膜铜衬底抛光质量对薄膜表面结构的影响

合金薄膜具有良好的导电性、抗磨损性质,已成为半导体产业的技术热点.铜做为合金薄膜衬底材料时,要求其有完美的表面.本文采用氧化铝微粉和金刚石抛光膏对合金薄膜铜衬底进行了机械研磨和抛光的实验研究,采用接触式粗糙度仪、AFM、台阶仪和光学显微镜对比分析了铜衬底表面粗糙度、表面均匀性和平面度的变化规律.初步探讨了铜衬底表面对Pd-Ni-P合金薄膜表面结构的影响,研究结果表明采用1 μm平面度,Ra小于3 nm且抛光均匀性好的光滑铜衬底可以获得良好的合金薄膜.     

定偏心和不定偏心平面研磨均匀性的研究

对修正环形抛光机定偏心和不定偏心平面研磨进行了运动分析,给出了研磨盘上一点相对于工件的速度矢量与轨迹方程,讨论了研磨盘上不同位置的点的相对轨迹。在Preston方程基础上,建立了材料去除函数和研磨均匀性函数。实验结果与理论分析表明通过设置选择适当的转速比组合,可使工件获得均匀研磨,有利于工件平面度的提高。     

超声振动辅助研磨单晶碳化硅晶片工艺研究

针对传统研磨方法加工单晶碳化硅晶片存在的材料去除率低、磨料易团聚等问题,本文提出超声振动辅助研磨方法,并探究不同工艺参数（转速、磨料质量分数、抛光压力、磨料粒径）对单晶碳化硅晶片研磨效率和表面质量的影响规律。试验结果和理论分析表明:超声振动有效提高了单晶碳化硅晶片研磨的材料去除率;在研磨盘转速为50 r/min,磨料质量分数为2.5%,压力为0.015 MPa,磨料粒径为0.5 μm时超声振动对材料去除率的提升效果最明显,分别提升23.4%,33.8%,72.3%,184.2%。同时,通过对研磨过程中表面粗糙度的追踪检测,能确定不同粒径磨料超声振动辅助研磨的最佳时间。      

Defect-free Fabrication for Single Crystal Silicon Substrate by Chemo-Mechanical Grinding

IC chips are built on Si substrates which must have a high degree of crystalline perfection. The single crystal Si ingot is first sawn into wafers, each of which then undergoes lapping, etching and several steps of polishing to remove the mechanical imperfection and to achieve mirror surfaces. An alternative process has been newly developed by effective use of solid-state reaction between the CeO₂ abrasives and Si. Si is removed in a form of amorphous Ce-O-Si at a dry condition. The fabricated ?300 mm Si wafers are examined on both surface and subsurface. The results show that 1) the surface is generated by fixed abrasives following grinding dynamics, 2) no defect or mechanical (structural) imperfection is introduced during fabrication and 3) far better quality is achieved than that by CMP.     

长余辉发光粒子与光催化剂在SiC晶圆化学机械抛光中的协同作用

目的 获得一种可改善单晶SiC晶圆化学机械抛光(CMP)效率的复合增效技术，实现单晶SiC晶圆高效率和低成本的加工要求，并对其增效机理进行深入研究。方法 通过抛光实验和原子力显微镜测试，探究长余辉发光粒子(LPPs)与不同光催化剂的协同作用对SiC–CMP的材料去除速率和表面粗糙度的影响。结合扫描电子显微镜(SEM)、紫外–可见漫反射光谱仪(UV–vis)、光致发光光谱仪(PL)和X射线光电子能谱仪(XPS)等仪器的测试结果，研究LPPs与光催化剂的协同增效机理。结果 与传统CMP的条件相比，在光催化条件下采用LPPs(质量分数0.5%)+TiO2(质量分数0.5%)+ H2O2(质量分数1.5%)+Al2O3(质量分数2%)的抛光液时，SiC的材料去除速率(MRR)由294 nm/h提高到605 nm/h，同时获得的晶圆表面粗糙度(Ra)为0.477 nm。然而，采用含有LPPs和ZrO2的抛光液抛光SiC时，其材料去除速率和表面粗糙度都未得到明显改善。XPS测试结果表明，LPPs与光催化剂的协同作用增强了抛光液对SiC的氧化作用。UV–vis和PL测试结果显示，LPPs与不同光催化剂协同效果的差异主要与其光学性能有关。结论 在光催化条件下，LPPs和TiO2对单晶SiC–CMP具有协同增效的作用，然而LPPs和ZrO2没有展现出协同增效的作用，即LPPs与光催化剂的协同作用可以改善SiC–CMP的性能，但是光催化剂的选择需要考虑LPPs的发光特性。     

A comparison of techniques for the metallographic preparation of thermal sprayed samples

Metallographic preparation of thermal spray coated samples is often difficult because hard and soft materials, which normally require different polishing techniques, are commonly present in a single spraycoated sample. In addition, the microstructures of many spray- deposited materials make them prone to pull-out damage during cutting, grinding, and polishing operations. This study compares alternative metallographic techniques to prepare three common types of thermal sprayed coatings: (1) a plasma sprayed alumina-titania wear coating, (2) a plasma sprayed zirconia thermal barrier coating, and (3) a high-velocity oxy-fuel (HVOF) sprayed tungsten- carbide/cobalt (WC/Co) hard coating. Each coating was deposited onto a steel substrate and was prepared with metallographic protocols based on silicon carbide (SiC) papers, bonded diamond platens, and diamond slurries. Polishing with SiC papers generally produced edge rounding and significant pull- out, which increased the apparent porosity of the coatings. Polishing with bonded diamond platens produced less edge rounding, but some pull- out was still observed. Preparation by diamond slurry lapping consistently produced the best overall results. Porosity artifacts produced by polishing with SiC papers and bonded diamond platens also resulted in spuriously low hardness values for the WC/Co samples; however, hardness results for the two ceramic coatings were not affected by the polishing method.     

6H-SiC单晶紫外光催化抛光中光照方式和磨料的影响

研究紫外光辅助催化抛光6H-SiC单晶。用分光光度法定性检测不同光催化反应时间下甲基橙颜色变化和羟基自由基(·OH)浓度,研究无光照、光照抛光盘、光照抛光液3种光照方式及金刚石、碳化硅、二氧化硅、二氧化钛、硅溶胶5种磨料对6H-SiC单晶抛光的影响。结果表明:随着光照时间增加,·OH浓度增加;在3种光照方式下,不同磨料的材料去除率(MRR)均呈现光照抛光液>光照抛光盘>无光照的规律,且光照抛光液时的MRR比无光照时的MRR提升了18%～58%。随磨料硬度降低,光催化辅助作用对MRR的提高幅度升高,即紫外光催化辅助作用越明显;金刚石、碳化硅、二氧化硅、硅溶胶4种磨料抛光后的表面粗糙度都随MRR的增大而减小,但二氧化钛磨料的则相反,原因是二氧化钛磨料同时兼作光催化剂,增强了SiC表面的化学反应速率,使其化学反应速率大于机械去除速率。