Evaluation on residual stresses of silicon-doped CVD diamond films using X-ray diffraction and Raman spectroscopy

The effect of silicon doping on the residual stress of CVD diamond films is examined using both X-ray diffraction (XRD) analysis and Raman spectroscopy measurements. The examined Si-doped diamond films are deposited on WC-Co substrates in a home-made bias-enhanced HFCVD apparatus. Ethyl silicate (Si(OC2H5)4) is dissolved in acetone to obtain various Si/C mole ratio ranging from 0.1% to 1.4% in the reaction gas. Characterizations with SEM and XRD indicate increasing silicon concentration may result in grain size decreasing and diamond [110] texture becoming dominant. The residual stress values of as-deposited Si-doped diamond films are evaluated by both sin2ψ method, which measures the (220) diamond Bragg diffraction peaks using XRD, with ψ-values ranging from 0° to 45°, and Raman spectroscopy, which detects the diamond Raman peak shift from the natural diamond line at 1332 cm-1. The residual stress evolution on the silicon doping level estimated from the above two methods presents rather good agreements, exhibiting that all deposited Si-doped diamond films present compressive stress and the sample with Si/C mole ratio of 0.1% possesses the largest residual stress of ~1.75 GPa (Raman) or ~2.3 GPa (XRD). As the silicon doping level is up further, the residual stress reduces to a relative stable value around 1.3 GPa.

Residual stress analysis on silicon wafer surface layers induced by ultraprecision grinding

Grinding residual stresses of silicon wafers affect the performance of IC circuits. Based on the wafer rotation ultra-precision grinding ma-chine, the residual stress distribution along grinding marks and ground surface layer depth of the ground wafers are investigated using Raman microspectroscopy. The results show that the ground wafer surfaces mainly present compressive stress. The vicinity of pile-ups between two grinding marks presents higher a compressive stress. The stress value of the rough ground wafer is the least because the material is removed by the brittle fracture mode. The stress of the semi-fine ground wafer is the largest because the wafer surface presents stronger phase trans-formations and elastic-plastic deformation. The stress of the fine ground wafer is between the above two. The strained layer depths for the rough, semi-fine, and fine ground wafers are about 7.6 m, 2.6 m, and 1.1 m, respectively. The main reasons for generation of residual stresses are phase transformations and elastic-plastic deformation.

Experimental Research on Residual Stress in Surface of Silicon Nitride Ceramic Balls

The influence of the residual stress in surface of ceramic balls on the fatigue life is large, because the life of silicon nitride ball bearings is more sensitive to the load acted on the bearings than the life of all-steel ball bearings. In this paper, the influence of thermal stress produced in sintering and mechanical stress formed in lapping process on residual stress in surface of silicon nitride ceramic balls was discussed. The residual compress stress will be formed in the surface of silicon nitride ceramic balls after sintering. The residual tensile stress will be formed in surface of silicon nitride ceramic balls in lapping process, and the size of abrasive particle is smaller, such trend is stronger. In this paper the residual stress was measured by the xylometric measurement in which the material in surface was peeled with lapping. The distribution of residual stress in surface can be calculated with the variation in specific volume. The technological parameter with which the material was peeled by lapping was given, for minimizing the extra influence of the residual stress forming in peeling on the original residual stress in surface, the abrasive particle size would not be too small and the load impressed would not be too large. Some experimental researches on residual stress in surface of silicon nitride ceramic balls were made. The surface of silicon nitride ceramic balls presented residual compressive stress after sintering and the influence of the ball size on the residual stress is feeble. It is expected that the size of ball blank is same for achieving the same residual compressive stress in surface on balls after final machining. In lapping process, the surface of silicon nitride ceramic balls presented residual tensile stress, the larger the load which is impressed on single ball, the larger the amplitude of residual tensile stress is; the smaller the abrasive particle, the stronger the trend of plastic deformation is and the larger the amplitude of residual tensile stress is.

基于分子动力学的硅晶圆均匀减薄磨削研究

超精密减薄磨削加工是半导体硅晶圆制造的关键工艺环节之一。然而,亚表面裂纹、残余应力和微结构的晶格畸变是减薄磨削产生的主要损伤缺陷。通过硅晶圆的减薄磨削,研究等效应变和残余应力的分布,评价磨削损伤。首先,分别建立球形和三棱锥单颗粒金刚石磨削硅晶圆的分子动力学模拟模型,应用Lammps模拟软件,设计硅晶圆转速、砂轮转速、磨削量为工艺参数,模拟硅晶圆减薄磨削。其次,获得硅晶圆表面的应变、等效应变分布数据。将磨削时硅晶格上原子发生形变相对位移值作为损伤评价目标,计算损伤值。在此基础上,在φ300 mm硅晶圆磨削后样品上的7个位置上,分别进行10 mm×10 mm×0.3 mm的取样,应用Roman光谱仪,测试、获得每个取样点处的平均残余应力。进一步,通过硅晶圆磨削的模拟和试验测试,获得了不同位置各X、Y、Z方向应变、等效应变和残余应力的分布,结果显示硅晶圆表面的等效应变相差8.1%,残余应力相差9%。最终,表明该磨削的等效应变、残余应力分布均匀,工艺参数合理、可行,可为硅晶圆的超精密、高效减薄磨削加工提供理论依据。

惰性碳源对两步反应烧结碳化硅陶瓷组织和性能的影响

两步反应烧结可以降低反应烧结碳化硅中的残余硅含量,采用纳米炭黑为活性碳源,过量碳微球和金刚石分别为惰性碳源,通过两步反应烧结制备了碳化硅陶瓷,分析比较了两种惰性碳源的反应率,以及对碳化硅陶瓷力学性能和热学性能的影响。结果表明,在碳密度和烧结工艺条件相同的情况下,金刚石的反应率低于碳微球,制备的烧结体中残余硅较多。在1550℃保温6 h条件下,使用高硬度的金刚石为惰性碳源制备的碳化硅的显微硬度达(2488±133)HV,高于使用碳微球制备的碳化硅。但是由于使用金刚石为惰性碳源制备的烧结体中低导热的残余硅较多,导致使用金刚石制备碳化硅的导热系数较低,在1550℃保温6 h条件下为115 W·m-1·K-1,低于碳微球使用的碳微球。

面向超薄硅晶圆精密磨削工艺的内部残余应力分析

目的硅基集成电路的超薄化(通常厚度≤50µm)是高性能集成器件实现柔性化的关键,同时也满足了器件先进封装的需求。背面精密磨削是低成本、大规模制造超薄硅基集成电路的重要技术路径。然而,随着厚度的降低,本征硬脆的硅基器件的机械强度急剧下降,磨削的难度也极大增加。此外,当器件的厚度接近甚至低于有源层厚度(约为15μm)时,磨削过程中产生的缺陷和内部残余应力将严重影响超薄器件的性能和良品率。因此,控制磨削过程的缺陷和内部残余应力是突破超薄柔性硅基集成电路制备技术的关键,非常有必要深入分析超薄硅晶圆精密磨削产生的内部残余应力,建立起工艺参数与内部残余应力之间的定量关系。方法针对精密磨削工艺,基于磨轮与硅晶圆的几何运动学关系,将磨轮进给率对磨削过程的影响转变为对等效磨削深度的影响,建立了硅晶圆在单颗磨粒单次和多颗磨粒多次磨削下的有限元局部模型,探讨了工艺参数(磨轮转速、磨轮进给率、磨粒尺寸)、磨粒数量和磨削次数对磨削后的表面质量和内部残余应力的影响,开展了12英寸硅晶圆的自旋转精密磨削实验验证仿真。结果硅晶圆精密磨削后的内部残余应力主要集中于距离硅片表面约50 nm处,并沿深度方向快速减小。降低磨轮进给率和减小磨粒尺寸可以有效降低内部残余应力,提高表面质量。使硅片磨削后的表面及内部区域近似处于等双轴压缩应力状态,当磨轮进给率为0.5、0.35和0.2mm/s时,通过激光共聚焦显微拉曼光谱仪测得残余应力分别为(-185±33)、(-216±25)和(283±41)MPa,多颗磨粒多次磨削有限元仿真获得的残余应力分别为(-127±32)、(-171±43)和(-221±55)MPa,二者吻合较好。结论将磨轮进给率转变为等效磨削深度后,建立的多颗磨粒多次精密磨削有限元模型可以有效预测硅晶圆自旋转精密磨削的内部残余应力,为硅基集成电路薄化工艺的开发和优化提供了指导。

Measurement of residual stress in a multi-layer semiconductor heterostructure by micro-Raman spectroscopy

Si-based multilayer structures are widely used in current microelectronics. During their preparation, some inhomogeneous residual stress is induced, resulting in competition between interface mismatching and surface energy and even leading to structure failure. This work presents a methodological study on the measurement of residual stress in a multi-layer semiconductor heterostructure. Scanning electron microscopy（SEM）, micro-Raman spectroscopy（MRS）, and transmission electron microscopy（TEM） were applied to measure the geometric parameters of the multilayer structure. The relationship between the Raman spectrum and the stress/strain on the [100] and [110] crystal orientations was determined to enable surface and crosssection residual stress analyses, respectively. Based on the Raman mapping results, the distribution of residual stress along the depth of the multi-layer heterostructure was successfully obtained.

Dissection of QTLs for Hull Silicon Content on the Short Arm of Rice Chromosome 6

The QTL qHUS6 for hull silicon content in rice was previously located on the short arm of rice chromosome 6. By using an F2：3 population segregating in the RM587-RM19784 region harboring qHUS6 in an isogenic background, two QTLs for hull silicon content were detected, of which qHUS6-1 was located in the distal region and qHUS6.2 in the region proximal to the centromere. Three rice plants carrying small heterozygous segments in the target region were selected, of which two covered the qHUS6-1 region and the other covered the qHUS6-2 region. Three F2：3 populations were derived from the selfed seeds of the three plants, respectively. QTL mapping was performed using the two populations segregating in the qHUS6-1 region, and qHUS6-1 was delimited to a 147.0-kb region flanked by the markers RM510 and RM19417. Five groups of F3 lines with different genotypic compositions in the qHUS6-2 region were selected from the other F2-3 population. Two QTLs were separated with two-way ANOVA, of which qHUS6-2a was located in the interval defined by RM19706-RM19795 and qHUS6-2b in the interval RM314-RM19665.

Analysis of formation causes for "oil-burn" defects and control measures during cold rolling of silicon steel

It has been found through analysis of defect components and micrographs that ＂oil-burn＂ defects on non- oriented silicon steel surf＇aces, which of ten occur after cold rolling, are composed of Fe, O, Si and C. This study analyzed the fomation mechanism of ＇toil-burn＂ defects and the strategies to prevent them,and proposed, according to the equipment and process status in the production fields ,some relevant optimized control measures and process adjustment schemes from two perspectives of reducing the residual emulsion trod avoiding the specific temperature range. The results demonstrate that the application of the proposed optimization meastu＇es effectively inhibits the formation of ＂oil-bum＂ defects.

氟化钠提纯工艺研究

经过处理后的氟化钠原料中含有较多的硅酸钠杂质。为了去除其中的杂质,提高氟化钠的纯度,获得更高的工业价值。利用溶出硅胶与蒸发结晶操作过程相结合,设计了溶出硅胶-蒸发结晶提纯氟化钠工艺,提高了氟化钠的纯度,降低了硅的含量,并且改善了氟化钠产品的外观。在溶出硅胶实验中,考察了硫酸用量比、温度、时间、搅拌速率对脱硅过程的影响,并进行了正交试验。结果表明,在溶出硅胶实验中,综合效果最好的脱硅条件为硫酸的用量比(硫酸与氟化钠原料的质量比)为0.04、反应温度为25℃、反应时间为30 min、搅拌速率为300 r/min。在蒸发结晶实验中,当蒸发时间为60 min时,蒸发结晶提纯氟化钠的综合效果最好。在最佳的实验条件下,能得到纯度>98%,二氧化硅质量分数<0.5%的氟化钠产品。研究表明,硫酸与硅酸钠反应能溶出硅胶,再过滤分离能达到除硅的效果,而通过蒸发结晶,能进一步提高氟化钠的纯度。该研究可为提纯氟化钠、回收氟硅资源提供新思路。

基于硅橡胶薄膜的固相微萃取技术测定水中13种有机氯农药残留

为了有效监测环境水体中的有机氯农药(OCPs)残留,本研究开发了一种低消耗、弱基质效应、经济便捷的固相微萃取技术测定水中13种OCPs残留的方法。应用具有强选择性的硅橡胶(SR)薄膜为固相吸附材料,制备了简便易操作的固相萃取瓶,通过优化萃取方式、萃取时间、洗脱溶剂以及洗脱方式等条件,选择涡旋10 min进行SR薄膜对目标物的萃取,利用5 mL V_(正己烷):V_(乙酸乙酯)=1:1溶液洗脱SR薄膜上目标物,采用气相色谱仪进行检测。结果表明:方法检出限在0.001~0.132μg/L之间,定量限为0.2μg/L;决定系数(R^(2))>0.9973;在0.2、1、20μg/L 3个添加水平下,13种农药在水中OCPs的平均回收率在73%~109%之间,相对标准偏差在0.5%~13%之间(n=5)。利用该方法对巢湖、南淝河等合肥市内主要河流进行了13种OCPs残留的检测,结果发现13种OCPs的最高检出质量浓度为3.64μg/L。与已所报道的方法相比,该方法具有灵敏度高、操作简便、成本低等特点,在环境水体OCPs多残留痕量监测领域具有良好的应用前景。

基于超声冲击处理的多晶硅还原炉316L不锈钢焊缝消应力研究

电子级多晶硅生产设备有超洁净要求,使得超声冲击处理(Ultrasonic impact treatment,UIT)方法不适应于该类设备的消应力,因为处理导致的表面深坑、毛刺等缺陷可能挂污、藏水,降低产品纯度。鉴于此,研究UIT后打磨去除表面缺陷对引入的残余压应力的影响。结果表明,UIT能够有效将焊缝残余拉应力转变为压应力,高强度UIT和高覆盖率UIT在引入压应力上可达相近效果,打磨去除表面缺陷对残余压应力的影响不大。

有机硅高沸物及废触体资源化利用的研究进展

有机硅高沸物及废触体都是有机硅的副产物,前者Cl元素含量高、后者遇空气易自燃,其产量随有机硅行业的高速发展而急剧上升,环保压力不断增大。本文综述了近年来有机硅高沸物及废触体的资源化利用技术,分析了各种技术的优劣势。指出:未来有机硅高沸物及废触体的资源化利用技术可从梯级资源化利用、以废治废、物料循环利用、能量耦合等方面进行整合和升级。

无取向硅钢多工序残余应力的演化分析

针对无取向硅钢开卷应用时发生翘曲的现象,对某牌号无取向硅钢板在退火、精整、卷取三种工艺和自然时效前后的硅钢板进行了残余应力检测以及金相组织的观测,发现了不同工艺对硅钢板残余应力的影响。结果表明,轧硬板具有较高的残余应力水平且其横向残余应力要大于轧向残余应力,退火能有效的降低轧硬板的残余应力,残余应力的降低幅度最高可达50%。精整能有效的均衡硅钢板的残余应力,使差异较大的残余应力趋于一致。卷取可能会较大的增加钢卷内圈部分的残余应力。自然时效能有效的降低无取向硅钢卷的横向残余应力,而对轧向残余应力效果很小。

粉煤灰制备聚合氯化铝废渣资源化利用研究

为进一步提高粉煤灰综合利用率,以不同组成的聚合氯化铝废渣为原料,通过焙烧活化制备硅肥,研究原料中主要成分含量的变化对硅肥有效硅含量的影响,并确定硅肥主要物相及生态安全性。结果表明,以粉煤灰制备聚合氯化铝废渣为原料制备硅肥的技术路线可行;不同SiO_(2)含量的多种废渣在相同活化参数下制备的硅肥有效硅含量相近,均可达30%左右;硅肥的主要物相为偏硅酸钙(CaSiO_(3))和霞石相(NaAlSiO_(4)),当原料中铝含量较高时还会生成少量钙铝黄长石相(Ca_(2)Al_(2)SiO_(7));硅肥中砷、镉、铅、铬、汞5种重金属含量均远低于GB 38400-2019标准限值,满足生态指标。

甲基氯硅烷高沸物制备高沸硅油的折光率研究

对直接法合成二甲基二氯硅烷单体过程中副产的甲基氯硅烷高沸物进行水解、中和、水洗、相分离制得高沸硅油。研究了高沸物中三甲基三氯二硅烷及二甲基四氯二硅烷的共含量对I型高沸硅油产品质量的影响。结果表明,高沸硅油折光率与有机硅高沸物中三甲基三氯二硅烷及二甲基四氯二硅烷共含量呈正相关性,且在一定范围内呈线性关系。

甲基氯硅烷单体合成中浆渣物理形态与利用技术研究

针对有机硅甲基氯硅烷单体合成产物浆渣中含有大量游离态铜的问题,开展了关于浆渣的综合回收与利用技术的研究。通过对混合铜渣的矿物组成、元素赋存状态、嵌布特性等进行分析,确定了浆渣中铜的分选理论基础。基于此,为高效回收有机硅浆渣中的铜金属,设计了“低温煅烧+重选选矿”和“低温煅烧+浮选”的联合工艺。实验结果表明,低温煅烧和重选选矿联合工艺可以较好地回收废渣中的铜金属,同时也降低了污水处理等配套环保装置的处理难度及负荷,进而减轻对环境的污染。

金属离子及非硅稳定剂对化学机械浆漂白过程中过氧化氢稳定性的影响

本研究主要探讨了Ca^(2+)、Mg^(2+)、Fe^(3+)、Cu^(2+)、Mn^(2+)5种金属离子和6种非硅稳定剂对化学机械浆漂白过程中残余H_(2)O_(2)含量的影响。结果表明,Ca^(2+)、Mg^(2+)可以提高残余H_(2)O_(2)含量,Fe^(3+)、Cu^(2+)、Mn^(2+)降低了残余H2O2含量,且降幅明显。非硅稳定剂中羟基亚乙基二膦酸(HEDP)的钙铁螯合值最大,钙螯合值为434.0 mg/g,铁螯合值为243.6 mg/g。当Mn^(2+)质量浓度为1 mg/kg时,二乙烯三胺五亚甲基膦酸(DTPMP)在漂白过程中能够很好地抑制H_(2)O_(2)的无效分解,残余H_(2)O_(2)含量最高为4.0%,浆料白度最好为69.9%。

HL-2A装置硅化镀膜壁处理控制杂质行为研究

硅化壁处理能有效控制等离子体杂质和再循环水平,是HL-2A装置的常规壁处理手段。介绍了HL-2A装置的硅化壁处理系统以及硅化镀膜壁处理控制杂质行为的主要研究进展。HL-2A装置硅化壁处理系统包括离线硅化和在线硅化壁处理系统,分别采用辉光放电辅助沉积以及等离子体放电辅助沉积进行硅化镀膜壁处理。实验结果表明,离线硅化壁处理后氧杂质明显降低,但随着实验进行会逐渐增加,硅化镀膜寿命约150炮。为进一步开展研究,HL-2A采用了在线硅化壁处理技术,研究发现在线硅化壁处理过程中碳、氧、铁等杂质均有所减少。两种硅化方式下真空室内的H_(2)O、CO含量均明显降低,在线硅化壁处理耗气量远少于离线硅化。通过硅化壁处理,有效地提升了HL-2A等离子体性能,也为未来聚变装置稳态运行器壁的处理提供了重要技术参考。

硅衬底温度对电子束蒸发钛薄膜性能的影响

采用电子束蒸发法在硅衬底表面制备Ti薄膜。采用台阶仪、原子力显微镜、反射率测试仪、四探针电阻测试仪和应力测试仪分析了在不同衬底温度下所得Ti薄膜的厚度、表面粗糙度、镜面反射率、方块电阻和残余应力。结果表明,随着衬底温度从25℃升高到200℃,Ti薄膜的厚度、方块电阻和残余应力逐渐降低;表面粗糙度先减小后增大,镜面反射率则先升高后降低。