硅片研磨表面状态的改善和研磨液的改进

在硅片研磨过程中,由于应力的积累和剧烈的机械作用,硅片表面损伤严重,碎片率增加.介绍了一种改进的研磨液,不但把剧烈的机械作用转变为比较缓和的化学-机械作用,还能起到其他较好的辅助作用并对其各成分作用,进行了理论分析.硅片表面状态得到了一定程度的改善,提高了生产效率.     

硅-硅键合晶片在减薄过程中产生的应力及影响

硅-硅键合晶片在机械减薄过程中产生的应力使硅片产生弯曲变形,这种变形在其后的加工过程中会使图形发生扭曲或位移,导致硅片加工中途报废.经过应力消除处理后可以顺利完成加工.     

硅/硅直接键合的界面应力

硅/硅直接键合技术广泛应用于SOI,MEMS和电力电子器件等领域,键合应力对键合的成功和器件的性能产生很大的影响。键合过程引入的应力主要是室温下两硅片面贴合时表面的起伏引起的弹性应力;高温退火阶段由于两个硅片的热膨胀系数不同引起的热应力和由于界面的本征氧化层或与二氧化硅键合时二氧化硅发生粘滞流动引起的粘滞应力。另外,键合界面的气泡、微粒和带图形的硅片键合都会引入附加的应力。     

硅晶片氧化应力的红外光弹性测量及研究

本文利用红外激光光弹性仪,采用光测弹性力学中的Senarmont补偿法,解决了硅晶片小数级条纹值定量测量问题.在考虑硅晶体光弹性效应各向异性的基础上,实测了(111)、(100)单晶硅片的原始应力及氧化应力.对硅晶片原始应力的产生与消除、氧化应力在硅中的分布、氧化应力与氧化层厚度的关系、氧化应力随时间的变化等进行了研究.     

固化残余应力对倒装焊器件热–机械可靠性的影响

采用底充胶的与固化过程相关的粘弹性力学模型,通过有限元仿真的方法,模拟了底充胶的整个固化过程,计算出了热循环加载下硅片、底充胶/硅片界面、底充胶内部的应力分布及其幅值大小.结果表明:底充胶的固化过程及由此产生的固化残余应力不但使得硅片中的最大垂直开裂应力位置偏离中心线达1.6 mm之多,而且还劣化了热循环加载下底充胶中应力幅值约6.25%.最后得出了固化残余应力对倒装焊器件热–机械可靠性的影响是不可忽略的结论.     

大马士革镶嵌结构对Cu膜微结构及应力的影响

通过TEM、SEM、XRD和EBSD,观察了Cu互连线和平坦Cu膜的微观结构。采用薄膜应力测试分布仪和二维面探测器XRD,测量了平坦Cu膜和Cu互连线的应力,计算了Cu薄膜热应力的理论值。凹槽侧壁成为互连线新的形核区域,并且在平行于侧壁的方向形成较弱的(111)织构。与平坦膜相比,互连线晶粒尺寸明显变小(、111)织构较弱,且存在大量Σ3和Σ9晶界。平坦膜和互连线分别表现出压应力和张应力。降温过程产生的热应力为互连线的主要应力。     

背照式CMOS图像传感器的硅减薄湿法刻蚀工艺

针对背照式CMOS图像传感器制作工艺,提出了一种采用氢氧化四甲基铵液进行湿法刻蚀的背部硅片减薄工艺。分析了硅减薄工艺的整体流程,针对化学机械研磨后的湿法刻蚀工艺进行了实验。通过调整反应时间、硅片转速、喷嘴速度和摆幅,得到最优刻蚀参数,使厚度均值达到目标值,平整度控制在一定范围内。该湿法刻蚀工艺中,首先对硅片表面形貌进行修正,接着对硅片进行整体刻蚀,达到目标厚度,最后通过减薄得到BSI背部硅片。采用该硅片制作的图像传感器的成像质量得到提高。     

硅微机械陀螺仪封装应力研究

封装热应力会降低硅微机械陀螺仪性能,为了减小封装热应力,对封装热应力与封装材料之间的关系进行了研究.首先对封装的硅微机械陀螺仪结构进行了简化,建立了有限元模型,仿真并分析了在封装过程中陶瓷基底材料和粘接剂对热应力的影响.仿真结果表明,陶瓷基底和粘接剂的热膨胀系数与硅的热膨胀系数匹配,且粘接剂的杨氏模量较小时,热应力较小.粘接层厚度超过60μm,平面尺寸大于陀螺仪芯片尺寸时,热应力较小.     

高温高压微波化学反应器耦合窗的应力分析

一些高温高压微波化学反应器使用圆形陶瓷片作为介质耦合窗口。本文基于有限元的方法,对窗口在不同腔体内压和微波输入功率下的热应力和机械应力分布进行了计算,并且进行了分析比较。结果表明:介质耦合窗上的热应力和机械应力及其形变随着腔体内压和输入功率的变化而发生很大改变,并且在不同条件下介质耦合窗上主要作用应力也不同。主要作用应力对高温高压微波化学反应器窗口的结构设计具有很高的参考价值。     

硅晶闸管烧结应力的红外光弹性研究

参考热弹性理论和复合材料层间应力理论，研究了Ｓｉ片Ａｌ箔／Ｍｏ片烧结后的层间应力及硅片中的应力，热膨性能不同引起的热应力成硅片中的中间和边缘区域分布情况不一样，推导出适用于边级区域的应力计算表达式，用红外光弹测量获得晶闸管烧结工艺制备样品的应力分布光弹图，理论能较好地解释实验结果。     

太阳电池用Si片切割过程中浆料作用研究

Si片生产技术及工艺的进步使得太阳电池用Si片的切片厚度不断降低,而超薄的太阳电池用Si片必须通过多线切割机进行切割.基于Si片切割过程中砂浆性能对Si片表面质量、Si片成片率和切割线寿命的影响,分析了多线切割机中切削液的性能,并采用不同工艺参数多次进行试验,总结出了砂浆对太阳电池用Si片切割状态的影响因素.通过分析,得出了改善砂浆性能来提高多线切割机切片性能并获得更高的Si晶片表面质量的方法.     

Si单晶片切削液挂线性能的研究

Si片线切割过程中,切削液的挂线性能直接影响切片表面质量、切片速率、线锯寿命以及晶片成品率.为满足超大规模集成电路对Si衬底表面质量的要求,改进线切割液的性能,对影响线切割液性能的因素进行了分析,并通过实验对线切割液的挂线性能进行了研究,找到了比较适合Si片切割且挂线性能较好的切削液配比.     

Experiment study on electroplated diamond wire saw slicing single-crystal silicon

This paper conducted the slicing experiments of single-crystal silicon using a reciprocating electroplated diamond wire saw. The machined wafer topography and wire wear were observed by using scanning electron microscope (SEM). The influences of process parameters and cutting fluids on single-crystal silicon wafer surface roughness (SR), subsurface micro-crack damage (SSD) depth, total thickness variation (TTV) and warp were investigated. The bonded interface sectioning technique was used to examine the cut wafers SSD depth. Study results show that a higher wire speed and lower ingot feed speed can produce lower wafer SR and SSD; the lower warp of wafer needs lower wire speed and ingot feed speed; and low wafer TTV can be obtained by an appropriate matching relationship between wire speed and ingot feed speed. The synthetic cutting fluid has a better total effect to improve the wafer quality. The pulled-out of diamond abrasives is the main wear form of wire, which indicates that more research on improving the abrasives retaining strength on wire surface should be investigated in fixed-abrasive wire manufacturing process, in order to improve the wire life and wire saw machining process.     

Si片多线切割技术与设备的发展现状与趋势

介绍了Si片的多线切割宏观切割机理与微观切割机理,指出控制钢线张力减少钢线震动是切割工艺的重要指标。讨论了切割过程主要影响因素,钢线的外包Cu会造成Si片表面金属残留,钢线磨损影响Si片厚度,砂浆喷嘴和线网角度在形成水平薄膜层时能够获得好的表面质量。分析了钢线带动砂浆进行切割的核心工艺,给出了Si片切割工艺理论切片量的计算方法。并简要概括了目前多线切割技术及设备的国内外发展形势和未来发展趋势,指出未来多线切割技术将朝着提高加工精度与加工效率、降低成本、改良切割用钢线这几个方向迈进。     

Simultaneous in situ measurement of film thickness and temperatureby using multiple wavelengths pyrometric interferometry (MWPI)

Film thickness and temperature are two of the most important quantities in semiconductor manufacturing. They play a fundamental role in many standard production techniques like chemical vapor deposition (CVD, LPCVD, PECVD), thermal oxidation and diffusion. They are especially important for more recently developed technologies like molecular beam epitaxy (MBE), metal organic MBE (MOMBE), metal organic CVD (MOCVD), chemical beam epitaxy (CBE), etc. In this paper, an optical in situ method for simultaneous film thickness and temperature measurements-named multiple wavelengths pyrometric interferometry (MWPI)-is introduced, which is capable of high resolution (up to 0.1 nm for thickness and 0.025 K for temperature) and for real time data evaluation. It can be used for process control as well as in situ quality inspection without time delay or additional handling mechanisms and is suitable for monitoring single films as well as multilayer structures. MWPI is insensitive to vibration, rotation and misalignment of the wafer. Due to its optical basis it is also insensitive to hostile environments like high temperature and/or chemical reactive gases     

硅外延工艺与基座的相关性研究

硅外延使用包封SiC的石墨基座,基座的尺寸及基座上承载槽的形貌和硅外延片的滑移位错直接相关。为使高温下Si片内产生的应力不超过滑移位错产生的临界应力,必须使Si片处于均匀的温区。实际使用表明,基座边缘热辐射及热量被气流带走使基座两个边缘温度急剧下降,必须对边缘温区进行补偿及装片时避开基座边缘一定距离;高温时Si片通过基座获得热量并发生形变,基座上承载槽的形貌设计必须兼顾厚度匀匀性及Si片高温时形变的方向。研究表明,金属沾污尤其是重金属催化作用及过腐蚀是影响基座寿命的关键因素。     

叠层薄膜电容器精密切割技术

介绍了叠层薄膜电容器的生产工艺.以切割工序中直条母料切片机为例,讨论了提高切割精度的关键技术.通过保证母料送料精度和锯片切割精度,提高了切割精度.通过采用PPS润滑膜和对锯缝的合理设计,提高了切割端面质量.经过实际生产验证,达到了预期的目的.     

Stress distribution on [100] Si wafer mapped by novel I-V analysis of MOS tunneling diodes

The current-voltage (I-V) characteristics of metal-oxide-semiconductor tunneling diodes distributed over a 3-in Si wafer were analyzed to investigate the stress distribution on the wafer. Generally, the substrate injection saturation current (J/sub sat/) decreases as the gate injection leakage current (J/sub g/) increases, the latter being dominated by oxide thickness via a trap related mechanism. A universal curve to fit all analyzed data was found and it is suggested that devices with extremely high (low) J/sub sat/ at a given J/sub g/ should be located in areas of the silicon lattice with relatively high external compressive (tensile) stress because of the stress-induced bandgap variation effect. The mapped locations of the highly stressed devices on a 3-in [100] Si wafer correspond to the patterns of slips caused by thermal stress during rapid thermal processing, as described in previous reports.     

Study of thinned Si wafer warpage in 3D stacked wafers

3D (three-dimensional) wafer stacking technology has been developed extensively recently. One of the many technical challenges in 3D stacked wafers, and one of the most important, is wafer warpage. Wafer warpage is one of the root causes leading to process and product failures such as delamination, cracking, mechanical stresses, within wafer (WIW) uniformity and even electrical failure. In this study, the wafer warpage of thinned Si wafers in stacked wafers has been evaluated. Si wafer or glass was used as a thick substrate, and Cu or polyimide was used as the bonding material. The top Si wafer in the bonded stack was ground down to 20–100 μm, and wafer curvature was measured. Wafer curvature and how it relates to bonding material, substrate material of the stacked layers, and thickness of thinned Si wafer will be discussed.     

锗单晶切割工艺研究

多线切割机是一种将晶棒切割成晶片的设备,近年来得到大规模使用,其切割原理为利用高速运动的切割钢线将砂浆带入切割区,砂浆中的坚硬颗粒（主要为SiC）与晶棒进行磨削,进而起到切割作用。根据锗材料的特殊性,通过改变工艺参数（主轴平均转速,砂浆流量,砂浆供给方式等）与硅材料成熟切割工艺进行对比实验,进而稳定锗材料的切割工艺。