圆片测试中探针接触电阻的影响与改善方法

介绍了影响探针接触电阻的几个因素,探讨了在测试过程中探针表面的变化以及接触电阻变大的原因、接触电阻对测试的影响。提出了几种控制接触电阻的办法,从材料、探针卡制作方面控制接触电阻的产生,在测试生产过程中通过定期清针、吹氮气等方式减少针尖损耗并减小接触电阻,在测试技术上采用双针开尔文连接和其他一些优化方式避免接触电阻对电参数测试的影响。通过以上方式有效提高了测试准确性和测试过程的顺畅性。     

晶圆测试异常之烧针问题分析研究

在晶圆测试过程中,难免会出现一些异常问题,其中"探针(Probe needle)烧针现象"是个较严重的测试异常.由于探针针尖与电源PAD接触面积较小,数百毫安(mA)电流会将探针针尖氧化,这被称为烧针.该文通过案例分析,烧针现象和针尖清针的必然联系以及为了避免烧针,程序开发方面的一些注意事项.     

服务于IC产业的MEMS探卡

圆片级芯片测试在IC制造工艺中已经成为不可或缺的一部分,发挥着重要的作用,而测试探卡在圆片级芯片测试过程中起着关键的信号通路的作用。分析指出由于芯片管脚密度的不断增加以及在高频电路中应用的需要,传统的组装式探卡将不能适应未来的测试要求;和传统探卡的组装方法相比,MEMS技术显然更适应当今的IC技术。综述了针对MEMS探卡不同的应用前景所提出的多种技术方案,特别介绍了传感技术国家重点实验室为满足IC圆片级测试的要求,针对管脚线排布型待测器件的新型过孔互连式悬臂梁芯片和针对管脚面排布型待测器件的Ni探针阵列结构的设计和制造。     

用于功率放大器的随温度可调负压偏置电路

设计了一种应用于GaN功率放大器栅极调制的随温度可调负压偏置电路。电路由电压基准模块、温度传感器模块、比较器阵列以及误差放大器及其对应的功率管与反馈电阻等组成,通过基准电压与温度传感器输出电压的比较,输出数字控制信号到反馈电阻中的可变电阻模块,改变可变电阻阻值进而改变电路输出电压,实现芯片电压随温度可调。电路结构简单、易于实现、应用方便,同时电路中引入了修调电阻结构,极大提高了基准输出精度。电路芯片面积为1.10 mm×0.64 mm,采用0.5μm CMOS工艺进行了流片并完成了后期测试验证。结果表明,芯片可实现输出电压的随温度可调,有效解决了GaN功率放大器在相同的栅极偏置电压下输出功率随温度升高而减小的问题。     

微处理器在微区薄层电阻测试Mapping技术中的应用

本文利用微区薄层电阻测试的一种斜置四探针新方法，将扩散微区薄层电阻测试结果绘成全乍的灰度图，这种微区薄层电阻测试Ｍａｐｐｉｎｇ技术十分有利于评价材料的质量。在测试过程中应用微处理器，可立即数字显示相应的测量电压及微区的薄层电阻，加快了计算速度并有利于控制探针的合适位置。     

微处理器在微区薄层电阻测试Mapping技术中的应用

利用微区薄层电阻测试的一种斜置四探针新方法，将扩散微区薄层电阻测试结果绘成全片的灰度图，这种Ｍａｐｐｉｎｇ技术十分有利于评价材料的质量，在测试过程中应生处理器，可立即数字显示相应的测量电压及微区的薄层电阻，加快计算速度并有利于控制探针的合适位置。     

圆片级组装、测试一体化的后道工艺

<正> 为了在半导体后道制造工艺中有效地应用摩尔比例缩小定律,必须要有一体化的圆片级封装工艺,并且,它可以以圆片的形式进行测试、老化和其它操作。到目前为止,已有多种圆片级封装技术的报导,但几乎都没有涉及到圆片级的测试和老化问题。一种新的技术可以使圆片级 CSP(芯片尺寸封装)、圆片级测试和最终组装一体化。其核心技术是直接在圆片上制作微弹簧接触器。这类接触器已被25个以上半导体厂家和测试工厂广泛用于高平行度探针卡上。圆片上的接触器,在老化和测试中被用作柔性弹性接触接口,在组装中被用作一级互连——焊接或插接芯片到衬底上。     

基于ASL1000的Bandgap Trim设计及其算法研究

在芯片生产过程中,由于工艺的影响,带隙基准电压V_(BG)会存在偏差。在芯片测试阶段,需要对V_(BG)进行trim修调,使其满足芯片参数要求。简要分析了带隙基准电压误差的来源,提出了一种E-Fuse修调电路,通过程序中的代码控制修调电阻的大小,使V_(BG)满足要求。同时,在该修调电路的基础上,采用了一种新型算法,使得测试芯片V_(BG)的时间缩短了近558 ms,减少了测试时间,降低了测试成本。     

改变铝溅射材料解决电视机场功放电路中点电位漂移

集成电路芯片对器件参数的均匀性、稳定性要求很高。集成电路制造过程中由工艺异常引起的器件参数不均匀,直接影响着芯片性能和圆片良率。引起器件参数不均匀的原因千变万化,结合产品分析解决问题、保证芯片性能和工艺正常,是设计和产品工程师经常面对的问题。通过一个产品实例,从失效现象、原因分析、实验室分析佐证、设计改进方案到试验结果,介绍了通过改变铝溅射材料减小基区孔接触电阻、改善接触电阻均匀性,解决电视机场功放电路由于工艺问题导致的基区孔接触电阻不均匀、引起中点电位漂移的方法。     

参数测试问题?请在使用检修仪器之前检查探针接触电阻

参数测试仪广泛应用于半导体产品、工艺过程开发以及生产监控。当测试结果与预期不符合的时候,请首先检查信号路径以发现潜在的问题。参数测试系统将电流或电压输入被测器件(DUT),然后测量该器件对于此输入信号的响应。这些信号的路径为:从测试仪通过电缆束至测试头,再通过测试头至探针卡,然后通过探针至芯片上的焊点,到达被测器件,并最后沿原路径返回测试仪器。通常,测量仪器引进一些噪声或测量误差,更可能导致误差的原因是系统的其它部件。在对仪器进行检测前,最好先检查信号路径以发现潜在的问题。其中之一可能是接触电阻,它会受探针参…     

An Investigation of Wafer Probe Needles Mechanical Properties and Contact Resistance Changing Under Multiprobing Process

In the semiconductor industry, fabrication defects in integrated circuit chips are generally identified using a needle probe card. Ideally, the probe needles should have a high elastic modulus and should maintain a low contact resistance even following repeated surface contacts. Using a high-precision microforce tensile tester, this study commences by investigating the thermo-mechanical properties of tungsten (W), tungsten-rhenium (ReW), and beryllium-copper (BeCu) probe needles. The tensile tests are conducted at temperatures ranging from room temperature to 150 degC at a loading rate of approximately 4 mm/min. Stress-strain curves are constructed to examine the temperature dependence of the elastic modulus, yield stress, and fracture strain of each needle. The experimental data are then employed to develop an empirical formula to predict the stress-strain response of the three needles. Subsequently, a single-contact probing test is performed to investigate the effect of the overdrive displacement on the scrub mark length, contact force, and contact resistance for each type of needle. Finally, a multicontact probing test is performed to evaluate the effect on the contact resistance of surface particle accumulation on the probe tip following repeated surface contacts.     

Characterization of fritting phenomena on Al electrode for low contact force probe card

We have investigated the characteristics of fritting of thin oxide film on an aluminum electrode for application to a probe card with low contact force. The fritting is a kind of electric breakdown of oxide film on metal electrode. It can be utilized for making electric contacts between the test probe and the electrode on LSI chips without a large force. The voltage and the contact force needed to cause fritting on a sputtered Al film was measured using W, BeCu and Pd needle probes. The contact resistance was also measured. A fritting was occurred by applying a contact load of 1 mN and voltage of 5 V. The contact resistance decreases with increasing the maximum current that passes through the contact. A current of 500 mA is enough to obtain the contact resistance of 1 /spl Omega/, which is low enough in practical test of signal lines. No damages were found on the Al film by optical microscope and scanning electron microscope observation.     

Application of a Genetic Algorithm to the Design Optimization of a Multilayer Probe Card for Wafer-Level Testing

The number of input and output pads on high-performance IC devices has increased in recent years, and hence wafer-level testing is conventionally performed using a probe card with a multilayer needle layout. This paper employs ANSYS commercial software and a Genetic Algorithm (GA) to optimize the design parameters of a multilayer needle probe card such that the scrub marks produced by the different needle layers are of approximately equal length. A dummy probe card containing both a conventional multilayer needle layout and the optimized needle layout is then fabricated and used in a series of single-contact probing tests. The results reveal that the scrub marks produced by the optimized needle layout are both shorter and of a more uniform length that those produced by the conventional needle design. For both needle layouts, a lower and more stable contact resistance is obtained as the overdrive distance is increased. Finally, a multicontact probing test is performed to evaluate the effect on the contact resistance of probe tip contamination following repeated surface contacts. The results show that the needles in the optimized layout are less heavily contaminated than those in the conventional layout, and hence the contact resistance is both lower and more stable. As a consequence, the probe card requires cleaning less frequently and hence its service life is improved.     

关于LED单灯正向电压VF不良的探讨

文章基于LED芯片和LED单灯的工作原理和制程工艺,探讨了LED芯片封装以后正向电压K升高和降低的常见原因,并提出了改善措施。对于GaN基双电极芯片,由于芯片工艺制程或后续封装工艺因素,造成芯片表面镀层（ITO或Ni／Au）与P—GaN外延层之间的结合被破坏,欧姆接触电阻变大。对于GaAS基单电极芯片,由于封装材料和工艺因素,导致芯片背金（N—electrode）与银胶,或银胶与支架之间的接触电阻变大,从而LED正向电压VF升高。LED正向电压VF降低最常见的原因为芯片PN结被ESD或外界大电流损伤或软击穿,反向漏电过大,失去了二极管固有的I-V特性。     

Novel analysis model for investigation of contact force and scrub length for design of probe card

Fabrication defects in IC chips are generally identified using a multi-layer needle probe card. To prolong the life of the card, the needles in each layer should experience a similar contact force and should produce a scrub mark of minimal length. To facilitate the probe card design process, this paper proposes an analytical model for evaluating the contact force and scrub mark length of a single-needle probe as a function of the overdrive distance. The model is based on Castigliano’s displacement theorem and takes account of both the material and the geometric properties of the needle. The validity of the analytical model is confirmed by performing a series of finite-element simulations at overdrive distances ranging from 30 to 70 μm. In addition, experimental probe card tests are performed using a tungsten needle probe and an aluminum pad. A good agreement is found between the experimental and analytical results for overdrive distances in the range 50 ± 10 μm. Overall, the results presented in this study confirm that the proposed analytical model provides an accurate and convenient means of determining the optimal needle probe design given maximum permissible values of the contact force and scrub mark length, respectively.     

Low-Force Electric Contact Processes on Cu Electrodes

A contact process between large-scale integration (LSI) pads and test probes at low contact force is a key to developing a probe card with smaller pitch and higher pin count. In this paper, we report on the characteristics of low-force contact methods on Cu electrodes. One is the fritting process, in which an electric breakdown is utilized to break the surface oxide, and the other is the heating treatment in hydrogen gas aimed at deoxidizing the surface Cu oxide. Conventional tungsten needle probes were used as testing probes, and contact resistances at low contact force of 1-5 mN were measured. Contact resistances smaller than 1 Omega were obtained by the fritting processes, in which the voltage and the current were 10 V and 280-320 mA, respectively. A deoxidization process at over 260degC was found to be effective for decreasing the contact resistance. The X-ray photoelectron spectroscopy (XPS) was utilized to investigate the surface state of hydrogen-treated Cu, and the deoxidization of Cu₂O to Cu was observed in samples treated at 260degC, while no change was found in that at 150degC.     

An Experimental and Numerical Investigation Into Multilayer Probe Card Layout Design

This paper conducts experimental and numerical investigations into the microforce probing technique used to test the functionality of IC devices. The study commences by considering the case of a single tungsten needle probe and examines the relationship between the contact force and the scrub mark size on aluminum pads at various levels of overdrive and shooting angle. Subsequently, a three-dimensional computational model is developed to facilitate the design of an optimum multilayer needle card layout. The simulation results obtained for the profile and size of the scrub marks on the upper surface of the aluminum pads of an IC device are found to be in good agreement with the experimental observations. The validated model is then applied to analyze the effects of the tip length and beam length on the scrub mark profile and the stress distribution contours within the needle during a wafer level test. The results predicted by the finite-element model (FEM) for the scrub mark length under various beam lengths are used to specify a suitable design for a multilayer needle layout. Taking the case of DDR2 SDRAM of an aluminum pad of dimensions 70$mu$m$,times,$70$mu$m (length by width), the numerical results enable appropriate values to be assigned to the shooting angles, beam lengths, and tip lengths of the individual needles within a four-layer probe card.     

Geometric design for ultra-long needle probe card for digital light processing wafer testing

The probe card with ultra-long probing needles is specifically designed for probe testing of wafers that feature protruding housing for digital micromirror devices (DMD) for digital light processing (DLP) applications. Compared with a conventional short probing needle, an ultra-long probing needle leaves a smaller scrub mark on the pad during probe testing but it suffers the risk from buckling. In this work, three-dimensional finite element models were developed and validated by experiments for single conventional and ultra-long probing needles to analyze their mechanical responses during wafer-level probe testing. Following the Taguchi method, we conducted separate optimal geometric designs for an ultra-long probing needle with respect to the minimized scrub length and minimized buckling potential. It was found that a long beam length of the ultra-long probing needle is preferred in reducing both scrub length and buckling potential. A compromised design that considers minimizing scrub length and buckling potential conjointly but with different weightings was presented.     

Experimental method and FE simulation model for evaluation of wafer probing parameters

Wafer probing technology is a critical testing technology that is used in the semiconductor manufacturing and packaging process. A well-designed probing system must enable low and stable contact resistance when each needle-like probe makes contact with the IC chip-bonding pad. Mechanical contact using excessive probe force causes over-sized scrub marks that may damage the die pad and sizably deform the probe tip. In this paper, an experimental setup of a single tungsten needle probe making contact with an Al pad was employed to investigate the relationships between the overdrive, contact force, and scrub mark length. A three-dimensional computational probing simulation model was developed for analyzing dynamic deformations of the contact phenomena during wafer testing. The mechanical tensile strength of the tungsten needle was tested with a micro-tester to examine the tensile stress-strain relationship. The elastoplastic behaviors of the probe and die were taken into account in the simulation model. The resultant scrub lengths from the simulation were verified against the experimental data. Additional critical data, such as data of the scrub mark sinking on the die surface and the maximum Von-Mises stress level location at the probe tips, can be predicted. The experimental and numerical methods presented here can be used as useful performance evaluation tools to support the choice of suitable probe geometry and wafer probe testing parameters.     

厚膜电阻器短时过负载破坏性试验阻值变化趋势分析

该文介绍了厚膜片式电阻器短时过载试验时,按不同幅度施加高于规定的试验电压后,电阻阻值变化的情况。结果表明：电阻在过负载的情况下逐步施加不同倍数的额定电压,电阻值将逐渐变小;当施加的电压继续升高,电流开始向绝缘电阻减小的地方集中,所引起的热量将导致电阻体发生破坏,电阻值上升,直至开路。这对分析及预防电阻器在混合电路中发生阻值异常提供帮助。