低k电介质及其设备

低k电介质、Cu互连和CMP已成为90/65/45nm芯片制造的标准工艺。90nm工艺要求k=3.0～2.9,65nm工艺要求k=2.8～2.7,45nm工艺要求k=2.6～2.5,大多采用2.5多孔的低k电介质,如TI、台积电。对于22nm工艺,可能采用碳纳米管(CNT)替代Cu互连。     

电介质与聚合物薄膜电子束诱导电导特性

电介质、聚合物薄膜的电子束诱导电导特性是其电子显微检测以及绝缘性能研究的重要手段。基于Rutherford模型模拟电子的散射过程,利用电流连续性方程计算电荷的输运过程,采用数值计算结合实验研究了SiO_2、PMMA薄膜的电子束诱导电导特性。结果表明,由于电子的输运,样品内部净电荷密度呈现近表面为正、内部为负的特性,空间电场推动电子向衬底输运,产生电子束诱导电导。电流增益随偏压的增大近似线性增大;由于电子迁移率较低,相同条件下PMMA薄膜的电流增益值远低于SiO_2薄膜的相应值。诱导电导随束流呈现近似线性特性,对于本文1μm厚度的薄膜样品,电流增益随束能变化在约20 keV处呈现极大值。     

金刚石/硅复合膜的导热特性研究

用金刚石粉,用不同时间在两片镜面抛光的(111)硅基片上分别打磨.两片硅基片打磨后都仍保持镜面特征.采用微波等离子体化学气相沉积系统,利用氢气、甲烷和氧气为前驱气体,在同样参数条件下,在基片上制备了直径5 cm的金刚石薄膜.用扫描电镜和X射线衍射分析两片薄膜结构.分析结果表明其表面形貌基本相同都为(111)择优取向的金刚石薄膜;但X射线衍射分析表明打磨时间较长的薄膜中含有一定量在非晶成分.用热导测试仪测试两薄膜和硅基片的热导率约为:241.7 W/mK,192.9 W/mK和169.3 W/mK.结合扫描电镜和X射线衍射分析结果我们讨论了基底处理对金刚石/硅复合膜的导热特性的影响.     

Submicron Mapping of Thermal Conductivity of Thermoelectric Thin Films

A tool for evaluating thin-film thermal conductivity to submicron spatial resolution has been developed. The micro-instrumentation utilizes the thermoreflectance (TR) technique to characterize thermal conductivity and material uniformity. The instrument consists of a heating element for creating temperature gradients and an Invar bar with in?situ temperature monitoring for heat flux measurements. The thin-film sample is sandwiched between the heater and Invar bar while a microscope is used to direct light onto a cross-section of the sample and reflected light is collected with a camera. By using this technique, we can achieve submicron spatial resolution for thermal conductivity and eliminate contributions from thermal contact resistance, thereby also eliminating the need for sample preparation other than cleaving. The method offers temperature resolution of 10?mK, spatial resolution of 200?nm, and thermal conductivity measurement with 0.01?±?0.001?W/mK resolution. The thermal conductivity of a 0.6% ErAs:InGaAlAs thermoelectric (TE) element, prepared by molecular beam epitaxy (MBE) growth, obtained with the new instrument is 2.3?W/mK, while the average thermal conductivity obtained with the 3-omega method is 2.5?W/mK. Energy-dispersive x-ray (EDX) spectroscopy is also used to prove that the elemental composition has uniformity consistent with the material variation observed by the TR technique. Moreover, a temperature profile across a 0.6% ErAs:InGaAlAs TE element on InP substrate is imaged. Two different slopes, corresponding to different thermal conductivities, have been observed, showing that the thermal conductivity of the TE element is lower than that of the InP substrate as expected.     

一种测试多层膜系热导率的方法

提出了一种测试多层薄膜热导率的结构.用ANSYS有限元分析软件对该结构进行了仿真,分析了加热功率以及悬梁长度和宽度等因素对测试结构温度分布的影响.仿真结果与理论相吻合,验证了该方法的可行性.微桥结构多层膜系的热导率是影响器件性能的关键参数之一.该测量方法无须在真空中实施,结构简单,操作方便.     

45 nm芯片铜互连结构低k介质层热应力分析

采用铜互连工艺的先进芯片在封装过程中,铜互连结构中比较脆弱的低介电常数(k)介质层,容易因受到较高的热机械应力而发生失效破坏,出现芯片封装交互作用(CPI)影响问题.采用有限元子模型的方法,整体模型中引入等效层简化微小结构,对45 nm工艺芯片进行三维热应力分析.用该方法研究了芯片在倒装回流焊过程中,聚酰亚胺(PI)开口、铜柱直径、焊料高度和Ni层厚度对芯片Cu/低κ互连结构低κ介质层应力的影响.分析结果显示,互连结构中间层中低κ介质受到的应力较大,易出现失效,与报道的实验结果一致;上述四个因素对芯片低κ介质中应力影响程度的排序为:焊料高度＞PI开口＞铜柱直径＞Ni层厚度.     

Thermal Properties of Ultrathin Hafnium Oxide Gate Dielectric Films

Thin-film $hbox{HfO}_{2}$ is a promising gate dielectric material that will influence thermal conduction in modern transistors. This letter reports the temperature dependence of the intrinsic thermal conductivity and interface resistances of 56–200- $hbox{rm{AA}}$-thick $ hbox{HfO}_{2}$ films. A picosecond pump–probe thermoreflectance technique yields room-temperature intrinsic thermal conductivity values between 0.49 and 0.95 $ hbox{W}/(hbox{m}cdot hbox{K})$. The intrinsic thermal conductivity and interface resistance depend strongly on the film-thickness-dependent microstructure.      

低介电常数(low-k)介质在ULSI中的应用前景

本文讨论了ULSI的发展对低介电常数(low-k)介质的需求,介绍了几种有实用价值的low-k介质的研究和发展现况,最后评述了low-k介质在ULSI中应用的前景.     

激光表面硬化效果的计算与实验

本文从求解高能激光束加热工件产生的温度场入手，给出由于温度场引起的金属结构变化的计算模型，并求出处理后的表层硬度。利用这些计算公式对不同含碳量钢的热处理进行计算，得出了最终处理硬度与激光功率，钢含碳量等参数之间的关系，计算结果与实验数据吻合。     

Thermal Conductivity Measurement Methods for SiGe Thermoelectric Materials

A new technique to measure the thermal conductivity of thermoelectric materials at the microscale has been developed. The structure allows the electrical conductivity, thermal conductivity, and Seebeck coefficient to be measured on a single device. The thermal conductivity is particularly difficult to measure since it requires precise estimation of the heat flux injected into the material. The new technique is based on a differential method where the parasitic contributions of the supporting beams of a Hall bar are removed. The thermal measurements with integrated platinum thermometers on the device are cross-checked using thermal atomic force microscopy and validated by finite-element analysis simulations.     

高反膜绝对反射率的精确测量

利用光学谐振腔的透射谱特性，通过测量其透射光谱的极大、极小值，求出高反射率膜片的绝对反射率，测量误差为１０＾－４量级。     

FIB参数对低介电常数介质TEM样品制备的影响

研究了使用聚焦离子束(FIB)方法制备低k介质的TEM样品时离子束参数对介质微观形貌的影响,发现低k介质的微观形貌与离子束参数具有较强的相关性。传统大离子束流、高加速电压的FIB参数将导致低k介质多孔性增加、致密度下降;且k值越低,离子束参数影响越大。对于亚65nm工艺中使用的k值为2.7的介质,当离子束流减小到50pA、加速电压降低到5kV时,FIB制样方法对介质致密度的影响基本可忽略,样品微观形貌得到了显著改善;而对于65nm工艺中使用的k值为3.0的介质,其微观形貌受离子束参数的影响则相对较小。     

Dielectric Relaxation and Alternating-Current Conductivity of Highly Crystalline Poly (ethylene-2,6-naphthalenedicarboxylate) Films

Journal of Electronic Materials - The dielectric relaxation and alternating-current (AC) conductivity behavior of poly(ethylene-2,6-naphthalenedicarboxylate) are found to be sensitive to its degree...     

ULSI中低k介质的化学机械全局平坦化分析研究

针对常见的低k介质材料分析了其化学机械全局平坦化的机理,并进一步探讨了低k介质化学机械抛光中包括压力、磨料、pH值和温度在内的几个因素对于抛光速率和表面状态等方面的影响。     

Polymer Films with Metal-Like Thermal Conductivity,Excellent Stability,and Flame Retardancy

Polymers often have thermal conductivities that are too low to be used directly in thermal management applications. In this study, a poly(p-phenylene-2,6-benzobisoxazole) (PBO) film is prepared through a sol–gel-film conversion and annealing method that utilizes PBO nanofibers as building blocks. The polymer film shows an in-plane thermal conductivity of 36.7 W mK⁻¹, which is two orders of magnitude higher than those of most polymers (<0.5 W mK⁻¹) and 2.4 times that of 304-stainless steel. The high thermal conductivity is attributed to the highly oriented 3D interconnected nanofiber network resulting from the fine-tuning sol-gel-film conversion, and the annealing that further enhances the ordering of the PBO chains and the interactions between the nanofibers. Moreover, the PBO films exhibit excellent mechanical strength, thermal/chemical stability, electrical insulation, flame retardance, and improved UV resistance. The lightweight, robust, and easily processed PBO film with a metal-like thermal conductivity has promising potential thermal management applications.     

在线检测多晶硅薄膜热导率测试结构的设计与模拟

提出了一种在线测试表面加工多晶硅薄膜热导率的结构,推导了热学模型,给出了测试方法,用ANSYS验证了热学模型.该方法避免了测试结构放置在真空中的缺点,有望在工艺线上得到应用.     

SIMOX硅片埋氧层垂直方向热导率的测量

提出了一种简单、有效而且准确的测量SOI硅片埋氧层垂直方向热导率的方法,并采用这种方法测量了用SIMOX工艺制作的SOI硅片的埋氧层垂直方向的热导率.测量结果显示至少在5 5nm以上的尺度上对于SIMOX硅片的埋氧层垂直方向经典的热导率定义仍然成立,且为一明显小于普通二氧化硅的热导率(1 4W/mK)的常数1 0 6W/mK .测量中发现硅/二氧化硅边界存在边界热阻,并测量了该数值.结果表明,边界热阻在SOI器件尤其是薄二氧化硅背栅的双栅器件热阻的计算中不可忽略.     

SIMOX硅片埋氧层垂直方向热导率的测量

提出了一种简单、有效而且准确的测量SOI硅片埋氧层垂直方向热导率的方法,并采用这种方法测量了用SIMOX工艺制作的SOI硅片的埋氧层垂直方向的热导率.测量结果显示至少在55nm以上的尺度上对于SIMOX硅片的埋氧层垂直方向经典的热导率定义仍然成立,且为一明显小于普通二氧化硅的热导率(1.4W/mK)的常数1.06W/mK.测量中发现硅/二氧化硅边界存在边界热阻,并测量了该数值.结果表明,边界热阻在SOI器件尤其是薄二氧化硅背栅的双栅器件热阻的计算中不可忽略.     

在线检测多晶硅薄膜热导率测试结构的设计与模拟

提出了一种在线测试表面加工多晶硅薄膜热导率的结构,推导了热学模型,给出了测试方法,用ANSYS验证了热学模型.该方法避免了测试结构放置在真空中的缺点,有望在工艺线上得到应用.