汽车电子产品的零缺陷检测

汽车电子行业,由于高质量和可靠性要求,越来越多的客户追求零缺陷质量,零缺陷实现方法成为越来越多汽车电子制造商研究的课题。从产品设计实现、产品制造以及产品最终测试过程中,本文主要论述在产品测试检测以及数据分析中如何实现零缺陷,以及提升可靠性的老化筛选方法,有效地避免和筛选潜在失效产品的产生和流出,确保客户手中产品的零缺陷质量。     

An Efficient Contact Screening Method and its Application to High-Reliability Non-Volatile Memories

In modern automotive designs double contacts are mandatory to achieve high reliability products and avoid field returns due to contact issues during the lifetime of the product. Using double contacts in compact digital IPs like RAM, ROM or NVMs leads to a dramatic area penalty. High area efficient NVMs are using shared contacts to minimize the area needed to realize the NVM bit cells. Using double contacts would lead to an area increase of approximately 50 % of the NVM memory plane. The high quality standard defined for automotive applications can only be fulfilled with a sophisticated contact screening procedure. This work will present a contact screening procedure which is able to detect contacts with a resistivity outside the main contact resistivity distribution. Those outliers have a potential danger to fail during lifetime as shown in this paper.     

Model requirements for simulation of low-voltage MOSFET in automotive applications

This paper focuses on the modeling of low-voltage automotive power electronic circuits to obtain accurate system simulation, including estimation of losses. The aim is to compare several metal-oxide semiconductor field-effect transistor (MOSFET) models to find out which can be used for low-voltage, high-current automotive converter simulations. As these models are intended for system simulation, only analytical models are addressed as they may be implemented into any circuit simulator. The different modes of operation of the switches are described (commutation, synchronous rectification, avalanche...), and several models of the power MOSFET transistor, allowing for simulation in these modes, are presented. Special care is given to the parameter extraction methods and to the interconnection model of the commutation cell. The four test circuits used to identify the low-voltage power MOSFET model parameters are presented. Comparison between simulations and measurements obtained with a calorimeter are then detailed. This measurement method is accurate and offers a simple way to prove the quality of simulation results. It is shown that the parameter identification is of major concern to achieve high accuracy, as classical Spice models can give good results, providing the model parameters are correctly set.     

汽车电子封装趋势,考量及生产的特殊性

汽车电子是半导体行业成长较快的领域。安全、舒适、互联,和个性化是未来十年成长的主要动力。可靠性和性价比优势使支架封装仍占主导,而其它封装,如PBGA、堆叠式芯片尺寸封装(SCSP),和晶圆级封装(WLP)等,也正得到启用。MLF誖(QFN)应用广泛,具有很好的热电性能和设计灵活性。类似凹槽侧面可湿性焊点技术的创新,让MLF誖这种传统封装更具吸引力。更多传感器和MEMS用于汽车应用,封装形式主要为MLF誖,LGA和"凹槽MEMS"。资讯娱乐系统需要采用更多类型的封装形式。汽车电子封装生产所涉及的供应商管理、可靠性测试等因素必须与严格的汽车标准保持一致。     

Fast wafer level reliability monitoring as a tool to achieve automotive quality for a wafer process

This work describes and discusses fast wafer level reliability (fWLR) Monitoring as a supporting procedure on productive wafers to achieve stringent quality requirements of automotive, medical and/or aviation applications. Examples are given for the various reliability topics: dielectrics, devices, metallisation, plasma charging with respect to required test structures, stress methods and data analysis. Application areas of fWLR are highlighted and limitations considered. Further aspects such as relevant reliability parameters, sampling strategies and out of control action plans are discussed.     

Importance of multi-temp testing in automotive qualification and zero defects program

For automotive qualification of Integrated circuits (ICs), multi-temp testing is required by AEC-Q100. In this paper, we demonstrate the importance and necessity of this multi-temp testing in automotive qualification and zero defects program.During the qualification of one of our new products, we found that all samples could pass electrical testing at room temperature after high temperature operating life test, but a few of them failed at hot temperature. One transistor in the circuit was found to have large leakage current. Only at hot temperature, this leakage current was increased (>50 μA) and the fail was detected during hot electrical testing. Root cause was identified and design error is corrected before the release of the product. No failures are observed anymore.     

一种无人机视频信号的收发电路设计

为了提高无人机在恶劣环境下的工作能力,将从遥感系统中采集的视频信号转换为数字信号,设计了基于CPLD系统的FSK调制解调收发电路,用VHDL语言实现了FSK调制解调的设计;同时将CMOS反向器应用于接收电路,构成模拟放大器将信号放大。整个设计基于ALTERA公司的Quartus Ⅱ开发平台,使用MAXⅡ系列的CPLD芯片实现,并用OrCAD PSpice软件对放大电路进行仿真分析。实验结果表明无线收发电路能够保证图像传输质量,达到预期设计的无线传输要求。     

Automotive IC reliability: Elements of the battle towards zero defects

The battle towards zero defects consists of fast response to PPM signals, prevention of incidents and continuous improvement. In this paper elements of all three branches are treated. A PPM analysis tool called quality crawl charts is introduced that enables prediction of customer complaint levels based on an early set of warranty call rate data. The fact that the automotive industry is very cautious with process and product changes can be better understood better with a given practical example of a small change with (in the eyes of automotive) big consequences. Finally it is shown that continuous PPM reduction activities also have an effect on the number of EOS/ESD customer returns, and that this category of fails form a shared responsibility for both supplier and customer.     

Sensor development in the microcomputer age

The proliferating applications of LSI circuitry require inputs from sensors which are both high in performance and low in cost. The need for improved sensors is especially acute in microcomputer-based control systems, where sensor development is expected to pace system applications. This paper reviews the sensors needed for real-time automotive engine control and compares the present status of a number of competing approaches. The problems and potential of sensors using integrated-circuit processes technology age examined. Sensor comparisons must be viewed in the context of the total system, including the output data format and type of microcomputer interface required. For automotive applications, the time-analog format is shown to have advantages. Finally, the additional design freedom and changing emphasis in sensor design as the result of adding on-chip circuitry to silicon-based sensors is described.     

Characterization of the Evolution of IC Emissions After Accelerated Aging

With the evolving technological development of integrated circuits, ensuring electromagnetic compatibility (EMC) is becoming a serious challenge for electronic circuit and system manufacturers. Although electronic components must pass a set of EMC tests to ensure safe operations, the evolution of EMC over time is not characterized and cannot be accurately forecast. This paper presents an original study about the consequences of the aging of circuits on electromagnetic emissions. Different types of standard applicative and accelerated life tests are applied on a mixed power circuit dedicated to automotive applications. Its conducted emissions are measured before and after these tests, showing variations in EMC performance. Comparisons between each type of aging procedure show that the emission level of the circuit under test is differently affected.      

Fault-tolerant evolvable hardware using field-programmabletransistor arrays

The paper presents an evolutionary approach to the design of fault-tolerant VLSI (very large scale integrated) circuits using EHW (evolvable hardware). The EHW research area comprises a set of applications where GA (genetic algorithms) are used for the automatic synthesis and adaptation of electronic circuits. EHW is particularly suitable for applications requiring changes in task requirements and in the environment or faults, through its ability to reconfigure the hardware structure dynamically and autonomously. This capacity for adaptation is achieved via the use of GA search techniques, in our experiments, a fine-grained CMOS (complementary metal-oxide silicon) FPTA (field-programmable FPGA transistor array) architecture is used to synthesize electronic circuits. The FPTA is a reconfigurable architecture, programmable at the transistor level and specifically designed for EHW applications. The paper demonstrates the power of EA to design analog and digital fault-tolerant circuits. It compares two methods to achieve fault-tolerant design, one based on fitness definition and the other based on population. The fitness approach defines, explicitly, the faults that the component can encounter during its life, and evaluates the average behavior of the individuals. The population approach, on the other hand, uses the implicit information of the population statistics accumulated by the GA over many generations. The paper presents experiment results obtained using both approaches for the synthesis of a fault-tolerant digital circuit (XNOR) and a fault-tolerant analog circuit (multiplier)     

A 2.1-MHz crystal oscillator time base with a current consumptionunder 500 nA

A micropower crystal oscillator module for watch applications is presented. The integrated circuit is encapsulated with a 2.1-MHz crystal in a miniature vacuum package to reduce parasitic effects. The circuit comprises frequency tuning with a resolution of ±3 s/year [±0.1 parts per million (ppm)] and auxiliary circuits. A single output delivers a signal of 16 384 Hz with a frequency stability of ±2 ppm over the temperature range (-10 to 70°C). The oscillator core has two complementary active MOSFET's and amplitude stabilization in order to get both low power consumption and high stability. New coupling and biasing circuits between the oscillator and the dynamic frequency dividers allow to achieve a current consumption under 0.5 μA for a supply voltage between 1.8 and 3.5 V     

Electronic automotive clocks

Electronic clocks are rapidly becoming practical for automotive applications. These digital clocks promise not only superior timekeeping in automotive clocks, but they also could be used for a myriad of timing functions throughout the car. These range from turn signal flashers to top-speed limiting and safety-monitoring checks. Integrated circuits utilizing complementary metal oxide semiconductor devices (CMOS and silicon gate CMOS) make several system approaches feasible. This paper outlines some possible system approaches and summarizes considerations for CMOS IC's, quartz crystals, and electronic readout devices.     

Low-power operation using self-timed circuits and adaptive scalingof the supply voltage

Recent research has demonstrated that for certain types of applications like sampled audio systems, self-timed circuits can achieve very low power consumption, because unused circuit parts automatically turn into a stand-by mode. Additional savings may be obtained by combining the self-timed circuits with a mechanism that adaptively adjusts the supply voltage to the smallest possible, while maintaining the performance requirements. This paper describes such a mechanism, analyzes the possible power savings, and presents a demonstrator chip that has been fabricated and tested. The idea of voltage scaling has been used previously in synchronous circuits, and the contributions of the present paper are: 1) the combination of supply scaling and self-timed circuitry which has some unique advantages, and 2) the thorough analysis of the power savings that are possible using this technique     

Curvature-compensated BiCMOS bandgap with 1-V supply voltage

We present a bandgap circuit capable of generating a reference voltage of 0.53 V. The circuit, implemented In a submicron BiCMOS technology, operates with a supply voltage of 1 V, consuming 92 μW at room temperature. In the bandgap circuit proposed, we use a nonconventional operational amplifier which achieves virtually zero systematic offset, operating directly from the 1-V power supply. The bandgap architecture used allows a straightforward implementation of the curvature compensation method. The proposed circuit achieves 7.5 ppm/K of temperature coefficient and 212 ppm/V of supply voltage dependence, without requiring additional operational amplifiers or complex circuits for the curvature compensation     

Diplex Doppler radar for automotive obstacle detection

The usefulness of radar as an automotive obstacle detection system is currently being investigated. Possible applications of such a system presently are automatic braking and air bag actuation and eventually the totally automatic highway. One type of radar having possible potential for these short range applications is diplex Doppler radar. The microwave and electronic circuits basic to a diplex Doppler radar obstacle detection system are described in this paper. The system provides Analog outputs proportional to range, velocity, and time to impact relative to an obstacle, as well as indicating whether the velocity is opening or closing.     

七通道抗干扰GNSS接收机射频前端设计

针对目前全球卫星导航系统(Global Navigation Satellite System,GNSS)普遍存在的抗干扰能力弱的突出问题,研制了一款七通道抗干扰GNSS接收机,通过利用多模组合导航抗干扰技术及级联/组合空域、时域与频域等多重抗干扰技术来应对复杂电磁环境应用的需求。重点介绍了抗干扰GNSS接收机射频前端的设计方法,通过数理推导给出了产品设计需求与整个射频前端及各级电路的设计指标之间的定量关系,从而提供了在已知设计需求的条件下进行产品正向设计的设计准则与方法。通过产品投产和测试,测试结果与设计需求吻合,从而验证了该套设计方法有效可行,同时该套准则与方法具有很强的普适性。与同类产品比较以及整机试验表明,该产品的抗干扰能力(主要体现为最大可承受干信比)较同类产品提升20 dB以上,证明产品具有一定的先进性。     

Small geometry depleted base bipolar transistors (BSIT)—VLSI devices?

An essential characteristic of devices which are viable candidates for VLSI circuits is that they must have electrical characteristics which can tolerate process variations. Conventional bipolar junction transistors (BJT) are well known to be limited by punchthrough when vertical basewidths axe decreased; these devices are, however, relatively tolerant of linewidth variations. The depleted base bipolar transistor represents a limiting case when the metallurgical basewidth is allowed to shrink to zero. Such devices, also called bipolar static induction transistors (BSIT), have been proposed as candidates for VLSI logic circuits. This paper describes the basic device physics of depleted base transistors and presents experimental verification of the theoretical modeling. The two essential conclusions that are drawn are that such devices can only achieve performance (in terms of transconductance) comparable to BJT's when an electrical p-type base exists (n-p-n device) and secondly, that BSIT's have characteristics which are extremely sensitive to process variations (linewidths, junction depths, and doping profiles). As a consequence, we conclude that while pure bipolar transistors may play an important role in VLSI circuits, depleted base structures such as the BSlT, are unlikely candidates for such applications.     

汽车电磁仿真技术与应用

随着汽车智能化和网联化的发展,对汽车电磁兼容（electromagnetic compatibility,EMC）设计提出了更高的要求.在这一背景下,需要加快提升汽车EMC仿真预测的设计方法和手段,将电磁仿真预测融入整车开发过程中,减少后期整改的时间和成本,以适应新趋势所提出的EMC需求.本文主要介绍了汽车电磁仿真国内外的发展现状,对基于FEKO软件的汽车电磁仿真方法、仿真过程中发现的问题进行了阐述.     

转镜式激光照排机中的锁相电路

激光照排机是一种光机电相结合的产品 ,是计算机—激光编辑排版系统中的关键输出设备 ,由它输出的胶片的质量直接影响着印刷质量的好坏。而激光照排机中的锁相电路又是激光照排机电路部分的关键 ,成功锁相是实现照排机各项同步的基础。本文对转镜式激光照排机中的一种锁相电路进行讨论