The Center for Advanced Life Cycle Engineering (CALCE) is recognized as a founder and driving force behind the development and implementation of physics-of-failure (PoF) approaches to reliability, as well as a world leader in accelerated testing, electronic parts selection and management, and supply-chain management. CALCE is at the forefront of international standards development for critical electronic systems having chaired the development of several reliability and part selection standards. CALCE is staffed by over 100 faculty, staff and students, and in 1999 became the first academic research facility in the world to be ISO 9001 certified. Collectively, CALCE researchers have authored over 25 internationally acclaimed textbooks and well over
To develop scientifically based innovative methodologies that decrease life cycle risks for the next generation of electronic products and systems, and to provide an educational and technology transfer infrastructure for their rapid dissemination and utilization.
CALCE Center for Advanced Life Cycle Engineering Postings
Dec 05, 2022 | Haiyu Qi , Sanka Ganesan, Michael Pecht
This paper reviews the possible causes and effects for no-fault-found observations and intermittent fail- ures in electronic products and summarizes them into cause and effect diagrams. Several types of inter- mittent hardware failures of electronic assemblies are investigated, and their characteristics and mechanisms are explored. One solder joint intermittent failure case study is presented. The paper then discusses when no-fault-found observations should be considered as failures. Guidelines for assessment of intermittent failures are then provided in the discussion and conclusions....
Oct 31, 2022 | Anupam Choubey, Michael Osterman, and Michael Pecht
The global transition to lead-free (Pb-free) electronics has led component and equipment manufacturers to transform their tin–lead (SnPb) processes to Pb-free. At the same time, Pb-free legislation has granted exemptions for some products whose applications require high long-term reliability. However, due to a reduction in the availability of SnPb components, compatibility concerns can arise if Pb-free components have to be utilized in a SnPb assembly. This compatibility situation of attaching a Pb-free component in a SnPb assembly is generally termed "backward compatibility." This paper presents the results of microstructural analysis of mixed solder joints which are formed by attaching Pb-free solder balls (SnAgCu) of a ball-grid-array component using SnPb paste. The experiment evaluates the Pb phase coarsening in bulk solder microstructure and the study of intermetallic compounds formed at the interface between the solder and the copper pad....
Jan 26, 2022 | Kenny Mahan, Yong Sun, Bongtae Han1, Sungwon Han, Mike Osterman
Reliability of conformal coatings used to mitigate tin whisker growth depends on their ability to contain tin whiskers. Two key material properties required to assess the reliability of a polyurethane coating are documented experimentally: adhesion strength and puncture strength. A modified blister test using a predefined blister area is employed to assess the adhesion strength and a puncture test is employed to evaluate the puncture strength of the coating. After measuring the properties at time zero, the coatings are subjected to accelerated testing conditions (high temperature/humidity storage and temperature cycling) and the degradations of the coating properties are documented....
Dec 21, 2021 | Dr. Kourosh Kalayeh, Dr. Nathan Blattau
This paper cover the following points: - Objective 01: Preprocessing, - Introduction, - Objective 02: Automated FE Scripting, - Objective 03: Postprocessing, Reliability Analysis of PTHs, - Objective 03: Postprocessing, Manufacturability of Microvias...
Dec 16, 2021 | Vikram Srinivas, Michael Osterman, Robert Farrell
Package on Packages (PoP) find use in applications that require high performance with increased memory density. One of the greatest benefits of PoP technology is the elimination of the expensive and challenging task of routing high-speed memory lines from under the processor chip out to memory chip in separate packages. Instead, the memory sits on top of the processor and the connections are automatically made during assembly. For this reason PoP technology has gained wide acceptance in cell phones and other mobile applications. PoP technology can be assembled using one-pass and two-pass assembly processes. In the one-pass technique the processor is first mounted to the board, the memory is mounted to the processor and the finished board is then run through the reflow oven in a single pass. The two-pass technique has an intermediate step in which the memory is first mounted onto the processor....
Sep 08, 2021 | Michael Osterman
While the presence of silver in SAC solder provided excellent temperature cycling durability, the silver in high silver SAC alloy also made the solders susceptible to failures under drop/shock loading. To improve the drop/shock reliability, the silver content in SAC alloys was reduced from three percent, to as low as no silver. Solder dopants, also known as microalloy additions, are elements (typically 0.1% or lower) other than the main constituents of the alloy that have been shown to improve solder performance. Commonly used microalloy additions include nickel (Ni), bismuth (Bi), manganese (Mn), and antimony (Sb)....
May 01, 2019 | Bhanu Sood, Michael Pecht
Moisture can accelerate various failure mechanisms in printed circuit board assemblies. Moisture can be initially present in the epoxy glass prepreg, absorbed during the wet processes in printed circuit board manufacturing, or diffuse into the printed circuit board during storage. Moisture can reside in the resin, resin/glass interfaces, and micro-cracks or voids due to defects. Higher reflow temperatures associated with lead-free processing increase the vapor pressure, which can lead to higher amounts of moisture uptake compared to eutectic tin-lead reflow processes. In addition to cohesive or adhesive failures within the printed circuit board that lead to cracking and delamination, moisture can also lead to the creation of low impedance paths due to metal migration, interfacial degradation resulting in conductive filament formation, and changes in dimensional stability. Studies have shown that moisture can also reduce the glass-transition temperature and increase the dielectric constant, leading to a reduction in circuit switching speeds and an increase in propagation delay times.
This paper provides an overview of printed circuit board fabrication, followed by a brief discussion of moisture diffusion processes, governing models, and dependent variables. We then present guidelines for printed circuit board handling and storage during various stages of production and fabrication so as to mitigate moisture-induced failures....
Oct 20, 2016 | Carlos Morillo, Yan Ning, Michael H. Azarian, Julie Silk, Michael Pecht.
Pad cratering failure has emerged due to the transition from traditional SnPb to SnAgCu alloys in soldering of printed circuit assemblies. Pb-free-compatible laminate materials in the printed circuit board tend to fracture under ball grid array pads when subjected to high strain mechanical loads. In this study, two Pb-free-compatible laminates were tested, plus one dicycure non-Pb-free-compatible as control. One set of these samples were as-received and another was subjected to five reflows. It is assumed that mechanical properties of different materials have an influence on the susceptibility of laminates to fracture. However, the pad cratering phenomenon occurs at the layer of resin between the exterior copper and the first glass in the weave. Bulk mechanical properties have not been a good indicator of pad crater susceptibility.
In this study, mechanical characterization of hardness and Young’s modulus was carried out in the critical area where pad cratering occurs using nano-indentation at the surface and in a cross-section. The measurements show higher modulus and hardness in the Pb-free compatible laminates than in the dicy-cured laminate. Few changes are seen after reflow – which is known to have an effect -- indicating that these properties do not provide a complete prediction. Measurements of the copper pad showed significant material property changes after reflow....
May 12, 2016 | Yan Ning, Michael H. Azarian, Michael Pecht
Advances in miniaturized electronic devices have led to the evolution of microvias in high density interconnect (HDI) circuit boards from single-level to stacked structures that intersect multiple HDI layers. Stacked microvias are usually filled with electroplated copper. Challenges for fabricating reliable microvias include creating strong interface between the base of the microvia and the target pad, and generating no voids in the electrodeposited copper structures. Interface delamination is the most common microvia failure due to inferior quality of electroless copper, while microvia fatigue life can be reduced by over 90% as a result of large voids, according to the authors’ finite element analysis and fatigue life prediction. This paper addresses the influence of voids on reliability of microvias, as well as the interface delamination issue. ...
May 21, 2015 | Mohammed A. Alam, Michael H. Azarian, Michael Osterman and Michael Pecht
In this work the reliability of an embedded planar capacitor laminate under temperature and voltage stress is investigated. The capacitor laminate consisted of an epoxy-BaTiO3 composite sandwiched between two layers of copper. The test vehicle with the embedded capacitors was subjected to a temperature of 125oC and a voltage bias of 200 V for 1000 hours. Capacitance, dissipation factor, and insulation resistance were monitored in-situ. Failed capacitors exhibited a sharp drop in insulation resistance, indicating avalanche breakdown. The decrease in the capacitance after 1000 hours was no more than 8% for any of the devices monitored. The decrease in the capacitance was attributed to delamination in the embedded capacitor laminate and an increase in the spacing between the copper layers....
Dec 19, 2011 | "National Seminar on Physics and Technology of Sensors" (NSPTS) is a continued activity ever since it was conceptualized and organized first in 1994 by the Department of Electronic Science, University of Pune. Since then, the activity has grown into a well-attended national event in India, adored and awaited by the Sensors and Actuators community across the country.
Sep 01, 2011 | SMTA and CALCE at the University of Maryland are pleased to announce the west coast venue for the Symposium on Counterfeit Electronic Parts and Electronic Supply Chain
Aug 04, 2010 | SMTA and CALCE @ University of Maryland are pleased to announce the east coast venue for the Symposium on Counterfeit Electronic Parts and Electronic Supply Chain. The program will be held November 30 – December 2 at the University of Maryland in College Park, MD. Don’t miss this opportunity to network with government agencies and peers who are addressing the counterfeit problem.
Apr 09, 2010 | Through research and project development, the CALCE Prognostics and Health Management (PHM) Group demonstrates the value of prognostics and health management to the electronics industry. The CALCE PHM group continued its mission to educate the electronics community on the value of PHM at its 2010 Spring Technical Review meeting, held on March 18 at the University of Maryland, College Park.
Apr 09, 2010 | Each year, CALCE celebrates the achievements of exemplary research assistants at its semi-annual technical reviews. The Best Research Assistant Presentation Award honors the research assistant who demonstrates poise, confidence, and sound technical knowledge when presenting their research on sponsored projects. Awards are based on compiled totals of votes supplied by Technical Review attendees.
Apr 09, 2010 | Continuing its efforts to provide the electronics industry with the most current and relevant research on life cycle engineering, CALCE holds semi-annual technical reviews to apprise Electronics Products and Systems Consortium members on CALCE research and project development.
Mar 22, 2010 | SMTA and CALCE at the University of Maryland are pleased to announce a west coast venue for the Symposium on Avoiding, Detecting, and Preventing Counterfeit Electronic Parts.
Feb 23, 2010 | The Center of Advanced Life Cycle Engineering at the University of Maryland in collaboration with The Institute of Scientific and Industrial Research (ISIR) at Osaka University is pleased to announce the call for participation for the Fourth International Symposium on Tin Whiskers.
Oct 16, 2009 | The 2009 edition of China's Electronics Industry analyses the current status and development of China's key high tech industry in the context of the unique political, economic and science and technology forces in China today.
Mar 04, 2009 | In collaboration with CALCE, City University (CityU), Hong Kong, is opening a Prognostics and Health Management (PHM) Center of Excellence in ShenZhen, China. A large number of companies in China, particularly electronics companies in the greater GuangDong area, which includes ShenZhen, have shown great interest in PHM. Avionics, aerospace, computer, telecommunications and power companies are expected to become members of the new Center.