浅谈高加速寿命试验和高加速应力筛选

本文简要介绍了高加速寿命试验(HALT)和高加速应力筛选(HASS)试验技术的产生、作用及应用对象，重点阐述了HALT／HASS试验技术基本原理和试验过程．     

加速极限试验方法综述

介绍了高加速极限试验(HALT)与传统的可靠性试验的差异性,以及HALT和高加速应力筛选(HASS)技术及其应用;并对HALT/HASS技术的实施方案,HALT/HASS试验中应注意的问题,以及如何正确地看待HALT/HASS技术在产品研发与生产中的作用等内容进行了综述。     

高加速寿命试验和高加速应力筛选试验技术综述

高加速寿命试验和高加速应力筛选试验技术是近几年不断发展起来的可靠性新技术。就HALT＆HASS技术与传统的可靠性试验进行比较,重点阐述HALT＆HASS的概念、特点以及测试步骤和注意事项。     

高加速寿命试验和高加速应力筛选技术综述

介绍高加速寿命试验和高加速应力筛师技术的概念、测试步骤,并举例说明HALT和HASS试验箱的性能指标和详细参数、HALT和HASS试验系统的校准方法及注意事项。     

高密度封装IC的高加速应力试验研究

采用在线监测技术对高密度封装IC样品进行温度步进试验、温度循环试验和振动步进试验等高加速应力试验,确定了产品的耐受应力极限,验证了本试验方案和试验监测技术的有效性和可行性。通过失效分析,确定了高加速应力下电路的失效模式和失效机理。结果表明:高密度塑封IC元件在高加速温循应力下比在随机振动应力下失效更为集中,温循试验在-65~165℃温度范围内,失效显著且集中在3个循环以内,主要包括塑封料和引线框架、基板的分层以及内键合点脱离,样品耐受随机振动量级超过50grms。研究结果可为器件级高加速应力试验研究提供参考。     

电子设备可靠性的加速试验

简要介绍了可靠性加速试验基本原理和一般流程,以及可靠性试验技术形成和发展。提出了可靠性加速试验的实施规划,并重点阐述了可靠性加速试验中的高加速寿命试验（HALT）和高加速应力筛选试验（HASS）的相关内容,详细介绍了两者的区别和实施方法。针对试验应力类型选择、试验层次和试验条件的确定等方面进行了说明,给出了基本应用原则...     

高加速应力试验(HALT&HASS)

阐述了高加速应力试验的本质是通过施加远超过产品设计规范规定的各种应力,快速地将产品内部的薄弱环节和缺陷激发出来,为改进设计和剔除早期故障提供信息.高加速应力试验的优点是可以得到高可靠的产品,且大大缩短产品研制进度和降低成本.这里列举了部分在IT、电子、机电等设备上成功应用HALTHASS取得效果的国际企业。     

高加速寿命试验(HALT)与高加速环境应力筛选(HASS)

将高加速寿命试验与高加速环境应力筛选引入产品的设计、研制和生产中，可在产品批量生产前消除设计缺陷，缩减开发时间和成本，快速提高产品的可靠性并增强市场竞争力。     

高加速寿命试验和高加速应力筛选技术

文中简单介绍高加速寿命试验和高加速应力筛选（HALT＆HASS）技术,重点从其原理、试验方法阐述该技术如何缩减研发时间与成本,达到提高产品可靠性和增强市场竞争力的目的。     

高加速应力筛选(HASS)概述

高加速应力筛选（HASS）是一种新兴的试验技术，用于产品的生产阶段。在暴露和剔除产品的制造和工艺缺陷，提高可靠性，降低野外失败和返修率等方面非常有效。从研究开发HASS的背景出发，介绍了HASS的目的及作用，重点探讨了高加速的基本原理，典型的HASS过程。     

Compound semiconductor activation energy in humidity

Product reliability investigations typically include accelerated humidity testing. Originally, the “standard” test was a biased 85 °C/85% relative humidity (RH) lifetest for 1000 h. Recently, a substitute accelerated version of this test has been used. The accelerated version is called highly accelerated stress test (HAST). The HAST conditions are also biased, at 130 °C, 85%RH, and approximately 18 PSI overpressure. The duration of the HAST test is normally 96–100 h – to be equivalent to the 85/85 test. This study is intended to investigate thermal acceleration and show that equivalent HAST tests on compound semiconductors are more highly accelerated and could be conducted with much shorter durations.     

The appropriateness of plastic encapsulated microcircuits in aspecific wooden-round application

Improvements in design, materials, and processes of plastic encapsulated microcircuits (PEM) have increased their reliability dramatically, to the point where PEM can achieve the `20-year lifetime in unpowered storage' required by certain wooden-round applications. PEM are now the parts of choice from cost, market-availability, performance, and reliability viewpoints. Nevertheless, PEM require appropriate vendor selection, verification by highly accelerated stress test (HAST), and manufacturing precautions. The potential failure mechanisms of package damage, internal part corrosion, and intermetallic growth, due to high temperature and humidity exposure, have been largely eliminated by improvements in the plastic and in the assembly process, and by the addition of die passivation. Models and test methodologies for accelerating (and thereby identifying) these physical phenomena have been developed, proven by testing, and generally accepted within the industry. After thoroughly defining the application temperature/humidity environments, the models are used to define a test program to qualify candidate PEM. This program consists of a high temperature life test, a humidity/temperature HAST and a completely assembled board-level HAST. To insure that subsequent manufacturing processes at Textron DS (including higher assemblies) do not damage qualified PEM, the manufacturing flow has been modified to minimize human contact with components, to eliminate any potentially corrosive chemical interaction with PEM, and to minimize exposure to moisture     

A review on discoloration and high accelerated testing of optical materials in LED based-products

Reduction of intensity of light output is one of the most common degradation modes in light-emitting diode (LED) systems. It starts from the failure of the various components in the system, including the chip, the driver, and optical components (i.e. phosphorous layer). The kinetics of degradation in real life applications is relatively slow and in most cases it takes several years to see an obvious deterioration of optical properties. Highly Accelerated Stress Testing (HAST) set-up and a methodology to extrapolate the results to real time applications are therefore needed to test the reliability of LED packages and lens materials. Using HAST concept in LED industry is inevitable due to the necessity of assessing the reliability of new products in a short period of time. This paper aims at briefly clarifying the degradation mechanisms of optical components in LED packages and explaining how they contribute to the depreciation of light output of the LED systems. The concept of HAST and the way the reliability of LED packages can be evaluated will also be discussed.     

Virtual qualification of moisture induced failures of advanced packages

This paper presents a combined numerical and experimental methodology for predicting and preventing moisture induced failures in encapsulated packages. Prevention of such failures will enable efficient and optimal pre-selection of materials, their interfaces and geometric design with respect to the desired resistance to moisture. This virtual qualification methodology is illustrated for a specific BGA package which showed 50% failures (broken stitch-bonds) during HAST testing due to excessive warpage and/or delamination of different interfaces. For three different material combinations the moisture diffusion during the HAST test is predicted and subsequently thermo-mechanical-moisture simulations are performed where the effects of hygro-swelling, vapor pressure, thermal expansion and delamination on the failure mechanisms are predicted. The comparison of the simulation results of the different molding compounds with the observations of HAST testing indicates that the developed methods and models can predict the observed trends. Application of the presented methodology will result in shorter time-to-market and significant cost reduction due to reduced trial-and-error design cycles and effective material usage.     

Accelerated life test of high power white light emitting diodes based on package failure mechanisms

Accelerated life tests of high-power white light emitting diodes (LEDs) were conducted under an unbiased highly accelerated temperature and humidity test (HAST) and a normal aging test. The conditions in the unbiased HAST were 110 °C-85% RH, 130 °C-85% RH without bias. During the aging, the degradation mechanisms of optical power reduction and degradation of 455 mm blue wavelengths that were better than phosphors related yellow emission bands were observed. The microscopy analysis showed that this effect could be ascribed to the bubbling and discoloration of the silicone encapsulating material of the package. It is thought that these features are also responsible for the optical power reduction and thermal resistance increase.     

Qualification of plastic encapsulated microcircuits (PEM) for avionicsBased on ``Plastic Encapsulated Microcircuits (PEM) Qualification Testing'''', by J. A. Scalise, which appeared in the Proceedings of the 46th Electronic Components and Technology Conference, Orlando, FL, U.S.A., 28–31 May 1996, pp. 392–397. © 1996 IEEE.

Microcircuit package qualification testing is used to establish the reliability of integrated circuit processes and devices as they relate to part packaging. This paper presents the results of package qualification tests conducted on plastic encapsulated microcircuits (PEMs) and plastic discrete devices (diodes, transistors) used in avionics applications. Highly accelerated stress test (HAST) and temperature cycle (TC) test results, including part failure mechanisms and associated failure rates, are provided. A variety of plastic package styles and integrated circuit functions have been tested. Examples of package styles tested include small outline (SO), plastic leaded chip carrier (PLCC), thin small outline package (TSOP), plastic quad flat package (PQFP) and plastic dual-in-line (PDIP).Manufacturers' devices have been evaluated and various plastic compounds have been compared to determine which provide optimum reliability. The testing showed that package qualification performance of PEMs is affected by type of compound, passivation (including die coat) and die size. HAST failures are caused by moisture penetration of the package while temperature cycle failures result from coefficient of thermal expansion (CTE) mismatch effects.     

评定封装可靠性水平的MSL试验

随着塑料封装集成电路在众多领域中的广泛应用,封装的质量和可靠性水平越来越受到广大用户的关注。作为评定和考核封装可靠性水平的重要特征参数,除通常采用的环境试验如Autoclave(PCT)、HASTBias、THBias外,MSL(MoistureSensitivityLevel)试验已成为其中最重要的试验项目之一。     

智能手机用薄印制电路板技术与可靠性考虑

下一代智能手机为进一步减少其产品厚度,将需要非常薄的多层印制板。文章叙述了薄的任意层积层HDI板之三种不同的制造方法,对用这三种不同方法制造的测试样板进行相关可靠性测试,以确认制造高端智能手机用PCB技术的有效性。三种试验板均为八层积层板,整体厚度小于0.5mm。进行了再流焊试验、高低温循环试验、高加速应力试验,比较它们的可靠性优劣。     

热膨胀系数不匹配导致的塑封器件失效

塑封器件使用过程中由于塑封材料和芯片之间热膨胀系数的不匹配,导致在外界温度变化时的应力释放对芯片造成损伤。文中通过VLSI失效分析,对这种应力造成的芯片损伤进行了研究,并提出利用环境应力试验和可靠性分析的方法暴露热膨胀系数不匹配导致芯片损伤的技术。     

Lifetime acceleration model for HAST tests of a pHEMT process

We report the results of DC biased life tests performed on gallium arsenide pseudomorphic high electron mobility transistor (GaAs pHEMT) switches under elevated temperature and humidity conditions. The goal of this work was to determine whether the acceleration factors typically reported for silicon technologies are also appropriate for GaAs technologies. Toward that end we performed tests at three different temperatures and two different humidity conditions. Failure distributions were generated for each life test, and the results applied to an acceleration model commonly used for HAST. We determined the activation energy for the failures observed during these tests to be 0.81 eV; similar to values commonly reported for HAST tests of silicon technologies. In contrast, our results show significantly stronger stress acceleration due to relative humidity (RH^−10.7) than is typically reported for silicon (RH^−3.0). Examples of typical visual and electrical device failure signatures are shown.