光电器件薄膜附着力评价方法的研究进展

薄膜与衬底的结合性能一直备受关注.在各种情况下,薄膜的性能都依赖于其与衬底的附着力大小.为了提高附着强度,需要深刻理解附着力的机理和开发合适的附着力测试技术.从基准附着力、热力学附着能和实际附着力三个不同角度提供了附着力评价途径.作为广泛使用的附着力粘接测试技术,拉脱法和压带剥落法等方法在大量样品测试方面具有独特优势,...     

两种离子束方法制备Cr膜的分析研究

在室温下,采用离子束溅射同时经100 keV Ar 离子轰击的动态离子束混合技术和采用离子束溅射技术这两种方法制备Cr膜,并用XPS,SEM及AES对薄膜的结构、表面形貌、薄膜与基体附着力的影响等进行分析对比。结果表明,与离子束溅射技术制备的Cr膜相比较,动态离子束混合技术制备的Cr膜表面平滑,膜致密呈无气隙的柱状结构,且薄膜元素与基体元素混合形成的组分过渡层较宽,因而有效地提高了Cr膜的附着力。     

脉冲激光沉积类金刚石膜技术

脉冲激光沉积(PLD)技术制备类金刚石(DLC)薄膜存在着金刚石相含量较低、石墨颗粒多、薄膜与衬底附着力差、膜内应力大等技术难题,为此,研究人员研究出了多种技术措施,如通过引入背景气体、超快激光、偏压、磁场以及加热等措施提高了薄膜金刚石相含量;采用金刚石或丙酮靶材、减小单脉冲能量等措施减少了石墨颗粒;采用间歇沉积、真空退火、超快激光等措施减少了膜内应力;合理没计过渡层改善了膜与衬底间的附着力等.这些技术有力地推动了脉冲激光沉积技术的发展.     

金刚石薄膜的人工合成及其结合力的评估

在硬质合金ＷＣ—Ｃｏ基体上，用热丝ＣＶＤ法，人工合成出金刚石薄膜。利用Ｘ衍射、激光拉曼光谱和扫描电镜对金刚石薄膜的结构进行了测定，结果是令人满意的。精确测量金刚石薄膜与基体间的结合力是很困难的。本文报导了金刚石薄膜涂层刀具的实际切削结果，并以此来评估该涂层与基体间的结合力。     

VO_2薄膜的制备及表征

综述了目前VO2薄膜主要的制备方法(sol-gel法,蒸发法,脉冲激光沉积,溅射法和CVD)及其优缺点;以及X射线技术、光电子能谱、光谱技术、显微技术等表征手段在VO2薄膜研究中的应用。如何方便地获得准确化学计量的VO2,获得结晶性好的薄膜结构以及与基体间具有良好结合力的制备方法,是今后关注的问题。     

金属膜固定电阻器的成膜材料及工艺

Ni-Cr系合金是一种应用非常广泛的金属膜电阻器的合金材科。它具有电阻率高、方电阻值大、电阻温度系数小、薄膜与基体附着牢固、熔点低、易于用真空蒸发法制成薄膜的特点。 国内生产金属膜电阻器习惯于粉料蒸发,而国外同时存在三种不同的成膜材料和两种成膜工艺。本文着重讨论了采用国产Cr20Ni80合金线,增加时效处理工艺制成的薄膜及其性能。     

Zr过渡层对Al膜微结构与性能的影响

为了增加高频声表面波器件用Al薄膜的功率承受力以及与基体的附着力，同时不增加薄膜在化学反应刻蚀中的难度。并精确地控制图形的尺寸。采用电子束蒸镀法研究了Zr过渡层和薄膜固化工艺对Al膜微结构、形貌、电性能及机械性能的影响。结果表明。适当厚度(5-30nm)的Zr过渡层增强了Al膜的(111)织构，增加了薄膜与LiNbO3基体的结合力，200℃固化后电阻率明显降低．拥有Zr过渡层的Al膜具有良好的工艺性能，通过反应离子刻蚀易获得精确的换能器图形．     

ZnS上金刚石膜的过渡层设计和附着力研究

CVD ZnS 是中长波前视红外窗口和整流罩的合适材料,文中从折射率、热应力、透射波段和附着力等方面考虑,由实验设计出HfO2/ 非晶膜双层结构作为ZnS与金刚石保护膜间的过渡层,采用射频反应磁控溅射技术在ZnS表面制备过渡膜层,并采用划痕法研究了薄膜的显微结构对其与衬底间附着力的影响。结果表明,金刚石能够在HfO2/ 非晶膜过渡层上形核、生长,得到优质的保护膜,同时过渡层也缓解了金刚石膜与ZnS衬底间由于热膨胀系数的较大差异而引起的膜层脱落问题,单面沉积过渡层的ZnS在2～12 μm范围具有增透膜的作用。与AlN/非晶膜组成的过渡层相比,HfO2/非晶膜组成的过渡层具有更小的残余应力。在典型实验条件下,该过渡层与ZnS衬底附着性良好,研究发现薄膜的显微结构对附着力的大小有重要影响,形成细小致密的柱状纤维结构,有利于提高附着力。     

采用等离子干燥工艺提高镀膜附着强度稳定性

镀膜工艺设计应能有效脱附物理和化学吸附,才能保证附着强度工艺稳定性。设备运行后腔室内表面沉积物增加,通过分析变化影响探索出一种等离子干燥工艺方法,应用后提高了生产效率,保证了薄膜电路金属叠层间附着强度生产稳定性,满足产品工程应用的可靠性要求。     

氮化铝薄膜的椭偏法研究

文章采用真空磁过滤电弧离子镀法在单晶Si(100)基片上成功制备了氮化铝(AlN)薄膜,并利用椭偏法对AlN膜进行了研究.根据沉积方法的特点,建立合适的膜系进行拟合,得到薄膜的折射率、消光系数和几何厚度;分析薄膜与基片之间的附着方式为简单附着,以及引起薄膜材料比块体材料折射率偏小的原因为:薄膜中含有空隙,Al/N不符合化学剂量比,薄膜表面形成了Al2O3钝化层.     

Oxidation of Lead Frame Copper Alloys with Different Compositions and Its Effect on Oxide Film Adhesion

Oxidation of four typical lead frame copper alloys was investigated. The oxidation rate and adhesion strength of oxide films to copper alloy substrates were studied by measuring the thickness and carrying out peel tests. The results show that, although copper alloys C5191 and C7025 have thinner oxide films, a lower adhesion strength and a higher proportion of CuO were obtained than in the other copper alloys EFTEC64T and C194. The adhesion strength is mainly influenced by the structure of the oxide film of the copper alloys, especially the CuO/Cu₂O ratio in the film. The highest adhesion strength is obtained for the copper oxide film with a basic structure of CuO/Cu₂O/Cu and a CuO/Cu₂O ratio of about 0.1. The segregation of additional elements in the copper alloy plays an important role in the oxide film structure.     

In situ measurement of mechanical properties of polyimide filmsusing micromachined resonant string structures

Two in situ measurement schemes, using micromachined resonant string structures, for the measurement of the polyimide residual stress and polyimide/metal adhesion durability have been developed. The residual stress of polyimide films, DuPont PI-2555 and PI-2611, have been measured using a bulk micromachined string structure. According to the Rayleigh's method, the resonant frequency of a polyimide string can be related to the film stress. By measuring the resonant frequency of these polyimide strings, the residual stresses have been calculated. The measurement results of various strings have been compared with conventional measurement results, which shows that they are in good agreement. Also, a noble scheme to quantize the adhesion durability between a polyimide film and a metal film has been developed. This scheme is based on a polyimide/metal bimorph string structures, fabricated using a surface micromachining technique, vibrating with an alternating potential. The change of resonance profile of this string structure can be related to the degradation of adhesion strength at the polyimide/metal interface. Various polyimide/gold string structures have been fabricated using a surface micromachining with Cu sacrificial layers, and the resonant qualities have been monitored. Notable changes of resonant Q-factor and resonant frequency, due to the degradation of adhesion between the metal and polyimide, have been observed after 10 ⁸ cycles (string vibration) for the polyimide/gold bimorph strings. The changes of resonant Q-factor and resonant frequency over a time period (vibration cycles) have been monitored     

氧等离子体处理对ITO薄膜表面性能的影响

利用原子力显微镜研究氧等离子体处理对ITO薄膜的微观表面形貌及表面润湿性能的影响。实验结果表明:经过氧等离子体处理,ITO薄膜的平均粗糙度和峰-谷粗糙度减小,薄膜的平整度提高;而且表面吸附力增大近一倍,表面能增大,接触角减小,使ITO薄膜表面的润湿性能和吸附性能得到改善。     

Role of residual stress on crack penetration and deflection at a bimaterial interface in a 4-point bend test

The four-point bend (4PB) test has emerged as a method of choice in the semiconductor industry for obtaining bimaterial interface adhesion data. When measuring the interface adhesion using 4PB test, it is essential to obtain a crack through the interface of interest. In our previous work the effect of finite flaw size, boundary conditions and film thickness on the crack deflection or penetration at a bimaterial interface was studied, and it was determined that prior work on semi-infinite media cannot be directly used in the case of 4PB test. In this paper, we briefly discuss the origins and development of residual stress, and will expand our previous work to include the role these residual stresses play on the competition between deflection and penetration energy release rates of a bimaterial interface and the extent of which the previous assumption of two semi-infinite media can be accepted.     

带胶剥离工艺粘附性实验研究

带胶剥离是微电子工艺的常见工艺步骤.文章通过对带胶剥离的样品进行退火实验,研究了电极蒸发金属和不同基底的粘附特性.实验表明,带胶剥离工艺制备的电极,其金属与衬底的粘附性差,退火过程产生气泡,严重影响了器件的特性.蒸发温度、蒸发室真空度,以及基片表面的清洁度与气泡产生有密切的关系.从这几点入手,提出了相应的改进方法.     

Laser soldering for chip-on-glass mounting in flat panel display application

Chip-on-glass (COG) mounting of area array electronic packages was attempted by heating the rear surfrace of a contact pad film deposited on a glass substrate. The pads consisted of an adhesion (i.e., Cr or Ti) and a top coating layer (i.e., Ni or Cu) was heated by an UV laser beam transmitted through the glass substrate. The laser energy absorbed on the pad raised the temperature of a solder ball which was in physical contact with the pad, forming a reflowed solder bump. The effects of the adhesion and top coating layer on the laser reflow soldering were studied by measuring the temperature profile of the ball during the laser heating process. The results were discussed based on the measurement of reflectivity of the adhesion layers. In addition, the microsctructures of solder bumps and their mechanical properties were examined.     

A comparative study on the measurement of toughness of stacks containing low-k dielectric films

Good adhesion strength of thin film stack is desirable for the integrated circuits (IC) manufacturing stage such as chemical mechanical planarisation (CMP). The scratch test and four-point bending test are two most commonly used methods to find the adhesion properties of thin film because of their simplicity and quantifiability. In this research, scratch test is used to find the practical adhesion energy (W_pa) of thin film stack and four-point bending test is used to find the critical strain energy release rate (G_c). The comparison of W_pa from scratch test and G_c from four-point bend test reveals that, for the same thin film stack, W_pa value is comparatively higher than G_c. The scratch test is semi-quantitative, in that the normal load at which a predefined failure event or delamination occurs is defined as a measure of adhesion. However, the four-point bending test is more quantitative in finding the adhesion properties. Thus, for practical application, such as CMP process, the G_c measurements from four-point bending test are recommended as references.     

Termination materials for thin film resistors

The resistance of a thin film resistor can be considered as consisting of three parts: 1) the resistance of the resistor material, 2) the resistance of the termination material, and 3) the interfacial resistance. The aging of the interfacial resistance can dominate the aging of low valued resistors, especially under corrosive conditions. The interfacial resistance using a distributed parameter analysis is treated and a figure of merit which can be used to describe the aging of the interface is defined. Also, a sensitive method of measuring this quantity is introduced and a sampling of data on several different termination material systems is presented. The best results were obtained with Ti-Pd-Au. The conclusions drawn from the figure of merit are corroborated by adhesion and thermocompression bond strength studies.     

基于容抗法的瞬时液膜厚度测量系统设计

设计了一种采用容抗法测量气液两相流瞬时液膜厚度的测量系统,通过测量气液两相流瞬时液膜厚度,来反映气液两相流截面持液率大小。对容抗法测量瞬时液膜厚度的原理进行了详细分析,建立了探针电容传感器的数学模型,完成了检测电路设计。根据此数学模型,确立了瞬时液膜厚度与输出电压的线性关系。在虚拟电子工作平台上,对该测量系统做了仿真实验分析,仿真数据表明该测量系统是切实可行的。