基于尺寸效应的Cu/CuNi薄膜热电偶灵敏度研究

采用磁控溅射法在镀有SiO2阻挡层的基底上制备了一系列的Cu/CuNi薄膜热电偶,其厚度分别为0.5,1.0,1.5和2.0 μm,测得四种Cu/CuNi薄膜热电偶的灵敏度,分别为46.47,45.23,44.32和43.98 μV/℃,通过实验和理论研究了薄膜热电偶灵敏度S与厚度δ之间的关系.结果表明:Cu/CuNi...     

T型薄膜热电偶灵敏度与薄膜电阻率的关系

在优化薄膜制备工艺的基础上,通过实验对Cu、CuNi薄膜的电阻率与T型薄膜热电偶(TFTC)灵敏度之间的关系进行了研究。首先,通过设计正交试验,以Cu、CuNi薄膜电阻率为考察指标,得到了影响电阻率的主次因素以及各工艺参数对薄膜电阻率的影响规律。然后根据实验结果确定工艺参数条件,制备出了薄膜电阻率不同的3个T型薄膜热电偶,并对其灵敏度进行了实验标定。标定结果表明:T型薄膜热电偶的薄膜电阻率越小,其灵敏度越大。     

金属基NiCr-NiSi薄膜热电偶的制备及性能研究

采用电子束蒸发和磁控溅射法在Ni基超合金基片上制备NiCr-NiSi薄膜热电偶,薄膜热电偶依次由Ni基超合金基片、NiCrAlY过渡层、Al2O3热氧化层、氧化铝绝缘层、NiCr-NiSi薄膜热电偶层以及氧化铝保护层构成。对此薄膜热电偶样品的静态标定结果表明,所制备的金属基NiCr-NiSi薄膜热电偶在25～600℃内具有良好的线性度,Seebeck(塞贝克)系数达到37.5μV/K,略低于K型标准热电偶的塞贝克系数40.0μV/K。     

磁控溅射工艺参数对Cu薄膜电阻率的影响

在确定Cu薄膜临界尺寸的基础上,选定基底温度、靶基距、溅射功率和工作气压为影响因素设计正交试验,研究了磁控溅射制备工艺对Cu薄膜电阻率的影响。研究结果表明:基底温度是影响薄膜电阻率的最主要因素,电阻率随着基底温度的升高而减小;在工艺条件为基底温度200℃、靶基距45 mm、溅射功率100 W、工作气压0.5 Pa时,所制薄膜的电阻率将会达到最小。最后,结合薄膜微观形貌对试验结论进行了分析,并对最佳工艺条件进行了实验验证。     

退火温度对Cr-Si压阻薄膜电性能的影响

采用射频磁控溅射法在氧化铝陶瓷基底上制备了Cr-Si-Ni-Ti压阻薄膜,研究了不同退火温度对薄膜电性能的影响.结果表明:在溅射态及退火温度低于600℃时,薄膜为非晶态.随着退火温度的升高,薄膜的电阻温度系数(TCR)逐渐增大,应变因子(GF)先增大后减小,室温电阻率(ρ)则逐渐降低.在退火温度为300℃时,Cr-Si...     

Al掺杂ZnO薄膜的XPS谱及电学性质研究

采用直流反应磁控溅射法在玻璃基底上用Zn(99.99%)掺杂Al(1.5%)靶制备出高质量的Al掺杂的ZnO(AZO)薄膜。用X射线光电子能谱仪对退火处理后的薄膜进行了成分和元素的价态分析,并用Van der Pauw方法对样品的电学特性进行了测量。实验结果表明,Zn和Al元素都以氧化态的形式存在,O元素主要是以晶格氧和吸附氧的形式存在。AZO薄膜的电学性质受退火温度和氧氩比的影响较大。随着退火温度的升高,电阻率减小,载流子浓度和迁移率增大。随着氧氩比的增大,电阻率增大,迁移率减小。因此可得到用直流反应磁控溅射法制备AZO薄膜的最佳氧氩比和退火温度分别为0.3/27和400℃,在此条件下制备出的薄膜电阻率可低至10-4Ω.cm,载流子浓度可达1020cm-3。     

退火温度对ZnO/PZT薄膜结构及电阻率的影响

采用射频反应磁控溅射法在Pb(Zr0.52Ti0.48)O3(PZT)/Pt/Ti/SiO2/Si基片上制备了ZnO薄膜,利用X线衍射仪(XRD)、原子力显微镜(AFM)、霍尔效应测试系统等对不同退火温度下制备薄膜的结构、形貌及电阻率等进行了分析表征。结果表明,退火温度600℃的ZnO薄膜(002)择优取向较好,晶粒大小均匀,表面平整致密。随着退火温度的增大,电阻率先下降后升高,600℃时ZnO薄膜电阻率达最小。     

A1掺杂ZnO薄膜的XPS谱及电学性质研究

采用直流反应磁控溅射法在玻璃基底上用Zn(99.99%)掺杂Al(1.5%)靶制备出高质量的Al掺杂的ZnO(AZO)薄膜.用X射线光电子能谱仪对退火处理后的薄膜进行了成分和元素的价态分析,并用Van der Pauw方法对样品的电学特性进行了测量.实验结果表明,Zn和Al元素都以氧化态的形式存在,O元素主要是以晶格氧和吸附氧的形式存在.AZO薄膜的电学性质受退火温度和氧氩比的影响较大.随着退火温度的升高,电阻率减小,载流子浓度和迁移率增大.随着氧氩比的增大,电阻率增大,迁移率减小.因此可得到用直流反应磁控溅射法制备AZO薄膜的最佳氧氩比和退火温度分别为0.3/27和400 ℃,在此条件下制备出的薄膜电阻率可低至10-4 Ω·cm,载流子浓度可达1020 cm-3.     

ULSI Cu互连CoSiN扩散阻挡薄膜的研究

CoSiN薄膜可以作为超大规模集成电路Cu布线互连材料使用。利用磁控溅射技术制备了CoSiN/Cu/CoSiN/SiO2/Si薄膜,利用四探针测试仪、薄膜测厚仪、原子力显微镜、X射线光电子能谱仪等来检测多层膜电阻率、薄膜厚度、表面形貌、元素含量及价态等。考察亚45 nm级工艺条件下CoSiN薄膜对Cu的扩散阻挡性能。实验结果表明,在氩气气氛条件下经500℃,30 min热退火处理后多层膜的电阻率和成分没有发生明显变化,CoSiN薄膜能够保持良好的铜扩散阻挡性能;经600℃,30 min热退火处理后,Cu大量出现在表面,CoSiN薄膜对Cu失去扩散阻挡性能。     

Ba0.6Sr0.4TiO3薄膜的耐压特性研究

采用射频磁控溅射法制备了Ba0.6Sr0.4TiO3(BST)薄膜,研究了基片、退火温度及膜厚对薄膜耐压特性的影响。结果显示,铝酸镧(LaAlO3)基片上制备的BST薄膜表面较平整,有较好的耐压;随着退火温度从750℃提高到850℃,BST薄膜晶粒长大,电击穿概率有所增加,750℃是一个较合理的退火温度。在优化的工艺条件下,BST薄膜耐压可达125V/μm。     

等温时效对SnSb4.5CuNi/Cu焊接接头力学性能的影响

SnSb4.5CuNi/Cu焊点在175℃进行等温时效,分析了不同时效时间的SnSb4.5CuNi/Cu焊点中金属间化合物(IMC)组织形貌演变,通过纳米压痕法测量SnSb4.5CuNi/Cu焊点界面IMC的硬度和弹性模量,对焊接接头进行拉伸强度和低周疲劳测试。结果表明,时效48 h的焊缝中Cu6Sn5呈曲率半径均匀的半圆扇贝状特征,IMC的弹性模量与铜基板很接近,在恒幅对称应变条件下焊点的抗低周疲劳的性能最佳,焊点的抗拉强度高;当时效时间大于48 h,焊接接口的抗疲劳性能和抗拉伸强度逐渐变差。     

Reactions of lead-free solders with CuNi metallizations

We have done experimental research on the dissolution rate and intermetallic growth on Cu, Ni, and CuNi-alloy substrates as a function of time and Cu/Ni ratio of the substrate. Reactions that occur when CuNi metallizations are soldered with lead-free solders were investigated. The experiments were performed using Sn-3.5Ag and Sn-3.8Ag-0.7Cu solders and different CuNi alloys. To determine the rate of dissolution of the substrate material into the solder, CuNi foils of different concentrations were immersed in Sn-3.5Ag and Sn-3.8Ag-0.7Cu solder baths for soldering times ranging from 15 sec to 5 min at 250°C. In addition, reflows of solder balls were made on top of bulk substrates to study the reaction when there is a practically infinite amount of CuNi available compared to the amount of solder. Thin film experiments were also done, where Ni containing under bump metallizations (UBMs) were fabricated and reflowed with eutectic SnAg solder balls. The nickel slows down the dissolution of the UBM into the solder and the formation of intermetallics during reflow compared to Cu metallizations. The solder/UBM interfaces were analyzed with SEM to find out how Ni concentration affects the reaction, and how much Ni is needed to obtain a sufficiently slow reaction rate.     

Cu diffusion in Ag-plated Cu leadframe packages

Cu diffusion onto an Ag-plated Cu leadframe surface was detected by Energy Dispersive X-ray (EDX) after de-capsulating the molded package. However, no Cu was detected by EDX on the Ag surfaces of bare leadframe, leadframe after die attachment including die attachment curing, or leadframe after wire bonding. Temperature simulation of molding and post-molding curing show that the temperature and its duration have some impact on the Cu diffusion, which is as expected. Interestingly, this study shows that the Cu diffusion onto the interface of the Ag-plated surface and mold compound is very much dependent on the type of mold compound used, which has never been reported in the literature so far. The Cu diffusion was detected by EDX only for certain types of mold compounds used. It is concluded that the mold compound is a major contributor to the Cu diffusion observed. This is possibly because S and O in the mold compound react with Cu and form copper sulfides and copper oxides, which accelerate the Cu diffusion from the Cu leadframe substrate onto the interface of the Ag surface and mold compound.     

Interfacial Reactions in Cu/Ga and Cu/Ga/Cu Couples

Cu-to-Cu bonding to connect through-silicon vias in three-dimensional integrated-circuit packaging is the most important interconnection technology in the next-generation semiconductor industry. Soldering is an economic and fast process in comparison with diffusion bonding methods. Ga has high solubility of up to 20 at.% in the Cu-rich face-centered cubic (FCC) phase and high mobility at moderate temperatures. In this work, an attempt has been made to evaluate Ga-based Cu-to-Cu interconnection by transient liquid-phase (TLP) bonding. The Cu/Ga interfacial reactions at temperatures ranging from 160°C to 300°C were examined. For reactions at temperatures lower than 240°C, the reaction path is Cu/γ ₃-Cu₉Ga₄/θ-CuGa₂/liquid, where the γ ₃-Cu₉Ga₄ and θ-CuGa₂ phases are thin planar and thick scalloped layers, respectively, while for the reactions at 280°C and 300°C, the scalloped γ ₃-Cu₉Ga₄ phase is the only reaction product. The phase transformation kinetics, reaction mechanisms, and microstructural evolution in the Cu/Ga couples are elaborated. In addition, reactions of Cu/Ga/Cu sandwich couples at 160°C were investigated. The original Cu/liquid/Cu couples isothermally transformed to Cu/γ ₃-Cu₉Ga₄/ θ-CuGa₂/γ ₃-Cu₉Ga₄/Cu couples as the reaction progressed. However, cracks were observed in the θ-CuGa₂ phase regions after metallographic processing. The brittle θ-CuGa₂ phase is undesirable for Ga-based TLP bonding.     

Cu/Nb微观复合线材中Cu沿径向的织构研究

本文利用电子背散射衍射(EBSD)技术,对含不同铌芯丝数的Cu/Nb微观复合线材中的Cu沿径向的织构进行了表征。结果表明:复合线材在拉拔过程中,各层织构存在差异,织构种类由表及里减少,且主要向平行于拉拔方向的<111>丝织构聚集;对于复合不同道次的样品,在相同部位,变形量大的线材内部织构更集中于<111>织构组分。     

A Comparative Study of Reactive Wetting of Lead and Lead-Free Solders on Cu and (Cu6Sn5/Cu3Sn)/Cu Substrates

Reactive wetting of solders on Cu and Cu₆Sn₅/Cu₃Sn/Cu substrates was investigated using both (1) the wetting balance, and (2) the hot-stage real time, in situ visualization of the triple-line movement. To understand the phenomenology of the spreading behavior better, comprehensive real-time in situ observations were performed. It was found that the wetting time during the wetting balance tests for both the lead solder (63SnPb) and lead-free solder systems (Sn0.7Cu and Sn3.5Ag) is shorter on Cu substrates than it is on Cu₆Sn₅/Cu₃Sn/Cu substrates. The wetting force was not remarkably different on these two substrates for the same solder system. The hot-stage tests indicate a more pronounced spreading of 63Sn-Pb on Cu₆Sn₅/Cu₃Sn/Cu substrates, along with a much larger spreading area. Spreading of lead-free solders in terms of the triple-line kinetics studied by using the hot-stage visualization shows no significant difference in the spreading evolution either over Cu or over Cu₆Sn₅/Cu₃Sn/Cu substrates.     

Cu/Nb微观复合线材中Cu沿径向的织构研究

本文利用电子背散射衍射(EBSD)技术,对含不同铌芯丝数的Cu/Nb微观复合线材中的Cu沿径向的织构进行了表征.结果表明:复合线材在拉拔过程中,各层织构存在差异,织构种类由表及里减少,且主要向平行于拉拔方向的〈111〉丝织构聚集;对于复合不同道次的样品,在相同部位,变形量大的线材内部织构更集中于〈111〉织构组分.     

Electromigration in Line-Type Cu/Sn-Bi/Cu Solder Joints

In this study, the different electromigration (EM) behaviors of eutectic Sn-Bi solder in the solid and molten states were clarified using line-type Cu/Sn-Bi/Cu solder joints. When the eutectic Sn-Bi solder was in the solid state during the EM test, a Bi-rich layer formed at the anode side while a Sn-rich band formed at the cathode side, and the intermetallic compound (IMC) at the cathode side was thicker than that at the anode side. The growth of the Bi-rich layer exhibited a linear dependence on the time of stressing. While the actual temperature of the solder joint increased to 140°C and the solder was in a molten state or partially molten state, two separate Bi-rich layers formed at the anode side and a great many Cu₆Sn₅ IMC precipitates formed between the two Bi-rich layers. Also, the IMC layer at the cathode side was thinner than that at the anode side. With a current-crowding-reduced structure, the products of diffusivity and effective charge number of Bi in the eutectic Cu/Sn-Bi/Cu solder joints stressed with current density of 5 × 10³ A/cm² at 35°C, 55°C, and 75°C were calculated.     

Cu—Invar—Cu印制板在功率SMT电路中的应用

本文介绍了Ｃｕ－Ｉｎｖａｒ－Ｃｕ（铜烟瓦）印制板的特点，及其在ＳＭＴ电路中的应用．