In response to the ever-changing needs of the electronics industry, CALCE has recently made additions to its already extensive facilities and services. These acquisitions will enable CALCE to provide our customers with a wider range of leading-edge research, characterization, and analysis services.
Process Control. As boards and assemblies evolve towards higher-density designs, the issue of product cleanliness has risen to the forefront, especially in the telecommunications industry. True root-cause analysis of migration failures due to contamination, which requires identification of ion type and concentration, is now available at CALCE through the use of the Dionex Ion Chromatograph. The Dionex allows for characterization of ion contamination, with sensitivities in the sub-ppm range, and is an important tool for benchmarking and quality tracking of production processes and contract manufacturers. Contact Dr. Michael Osterman for more information at osterman@calce.umd.edu.
High-power Electronics. To augment current capabilities in the characterization of high-power devices and systems, CALCE has recently purchased a Tektronix 371A High Power Programmable Curve Tracer. This allows parametric characterization of current gain, breakdown voltages, and impedance on high-power semiconductor components, such as those being developed in the ONR-sponsored Advanced Electrical Power Systems Program. Testing can be performed at voltages up to 3000 volts, current up to 400 amps, and power up to 3000 watts. The 371A provides a direct readout of the base/gate voltage or current and can display power curves without excessive heating of the device. For more information, contact Dr. Patrick McCluskey at mcclupa@calce.umd.edu.
Materials Characterization. One of CALCE's latest acquisitions is Digi Test, a computer-controlled hardness tester that enables hardness measurements of very soft rubbers/elastomers, especially polyolefins, fluoropolymers, vinyls, and silicones. Using the Digi Test, it is also possible to observe stress relaxation characteristics, providing information about the elasticity of the material, and hence its sealing capabilities. Since the hardness of an epoxy is higher for completely cured samples, hardness testing can be used to determine optimum curing parameters for each type of epoxy by comparing hardness readings for different settings. The effect of humidity changes during the curing process can also be investigated. For more information, contact Keith Rogers at dilcia@calce.umd.edu.
EMI/EMC. As part of its electromagnetic compatibility and interference (EMC/EMI) laboratory, CALCE has recently purchased two ultra-high frequency test and measurement devices. The Agilent E7405A EMC Analyzer is designed to evaluate, diagnose, and document the EMI performance of electronic products over a frequency range of 30 Hz to 26.5 GHz. It can be used in both radiated and conducted emission measurements. This equipment will be used in conjunction with an Agilent 83712B Synthesized Continuous Wave (CW) Generator, which operates in the microwave frequencies of 10MHz to 20GHz, allowing for a broad range of EMI/EMC test capabilities.
back to top
The past decade has witnessed a significant increase in computer processor speed. In fact, present processor development is approaching the 2GHz mark, with fundamental harmonics reaching well beyond 10GHz. While these advances are highly welcomed, their silent negative consequences are that electromagnetic (EM) radiation increases with processor speed. EM radiation, if unchecked, can interfere with the operation of nearby electronic devices and can pose a risk hazard to nearby biological organisms.
Moreover, the drive towards low-cost electronic packaging using non-metallic fixtures is creating unintended internal and external spurious radiation that can significantly alter the timing of electronic circuitry, leading to device incompatibility and hard-to-detect operation failures.
Increased internal and external electromagnetic pollution has made the efficient and optimal containment or shielding of EM radiation a major factor in the overall design of electronic packages. In fact, the Federal Communication Commission (FCC) and the European Community (EC) have reacted aggressively by imposing strict regulations on the amount of radiation allowed from each class of devices.
The significance of EM radiation in the package design process has led to the emergence of a separate discipline within engineering studies, referred to as electromagnetic interference (EMI) and electromagnetic compatibility (EMC).
The 'old way' of applying design rules, then fixing the EMI/EMC problems after the product is built is not acceptable in today's highly competitive development environment, when designs must pass regulatory requirements the first time through the design cycle.
For some time, CALCE has been using its expertise in electromagnetic interference and electromagnetic compatibility to address radiation and shielding problems. Recently, this research effort has been expanded with the addition of Dr. Omar Ramahi at our center. Dr. Ramahi joined CALCE as a faculty member in August of 2000. Prior to joining CALCE, he had worked at Compaq Computer Corporation for seven years, where he was part of the Alpha Servers Development Group.
Dr. Ramahi is currently constructing an advanced EMI/EMC characterization, testing, and measurements laboratory with the capability of investigating and testing novel designs that produce lower levels of radiation. He is also establishing a computational electromagnetic laboratory that will help identify effective designs. These capabilities will help establish appropriate design methods and testing procedures for EMI/EMC, and the results obtained will be used to characterize and quantify shielding reliability.
back to top
In October 2000, the CALCE Consortium initiated a large-scale research effort to study the consequences of replacing the current tin-lead eutectic solder in electronics. Following is a description of the research projects in progress:
Constitutive Properties of Lead-free Solder: Solder alloys perform at relatively high temperatures (compared to their melt temperatures) in typical use environments. Consequently, their mechanical behavior is highly nonlinear, and displays strong dependence on loading history and environmental conditions. Quantification of this constitutive behavior is important for accurate stress analysis, the results of which are then used to quantify damage accumulation due to life-cycle stresses. Since typical solder interconnects in modern electronics are extremely small (<100 mm), measuring the mechanical behavior is a significant engineering challenge. Test systems must be capable of delivering very small forces and displacements. A micro-mechanical tester and optical methods will be employed to determine constitutive properties and to verify them under actual operating conditions.
Durability Properties Characterization: Cyclic deformations in solder interconnects occur due to mechanical vibration or thermal expansion mismatches during cyclic variations in environmental temperatures or through power cycling. The resulting creep-fatigue failures in solder give rise to durability concerns that are explored in this study through the use of a thermo-mechanical-microstructural (TMM) test system. Developed during past projects, the TMM test has been used to characterize the fatigue durability of SnPb eutectic and Sn/Pb/Ag solder systems. The load frame was designed specifically for miniature specimens similar in scale to typical in-service solder joints. A solid-state piezoelectric linear actuator delivers displacements with a resolution of ?0 nanometers. In addition, the capability exists to study the solder material at a microscopic level in order to gain a more fundamental understanding of the nature of damage and failure in these highly complex materials. Durability is quantified by relating the measured cycles-to-failure to either the cyclic energy or the cyclic strain (determined through a hybrid experimental simulation technique) at the failure site.
Interfacial Strength and Cohesion: Solder interconnects fail not only due to fatigue of the solder material, but also due to imperfect bonding between the solder and the plating system used on the PWB bond pad or on the component metallization. Good surface wetting properties of SnPb eutectic and most lead-free solders come from an abundance of tin, which easily adheres to the plating metal by forming a thin layer of intermetallic. However, it is this same tendency of tin to form intermetallics that raises a long-term reliability concern in solders with high tin content. The intermetallics continue to grow, particularly at high temperature, resulting in the eventual formation of a thick layer of a very brittle material. This brittle intermetallic is prone to fracture, especially in the presence of voids created by asymmetric interdiffusion between the two source metals. Fracture of the intermetallic can lead to a catastrophic loss of adhesion at the interface. The interfacial strengths of lead-free solder alloys with standard surface plating systems are being explored using pull tests on aged specimens.
Compatibility of Electronic Components with Lead-free Soldering: The suggested lead-free alloys raise the solder melting point by as much as 40°C. A reflow profile recommended for use by component manufacturers has a peak temperature of 260°C, with a time above the melting point of up to ninety seconds for the full range of temperatures likely to be encountered during manufacturing. This profile is going to require much development work to qualify current and emerging components to these temperatures. In addition, new materials also need to be introduced to safeguard against moisture intake in component packages that will be subjected to the higher reflow temperature.
CALCE will evaluate the compatibility of current and emerging electronic components with a strict lead-free soldering environment. Test vehicles will go through preconditioning testing with a simulated lead-free reflow soldering process. An experimental setup developed at CALCE that simulates the reflow profile and measures the mechanical deformation during the simulation will be used for this test. Temperature cycling (TC) and highly accelerated stress testing (HAST) will be carried out to further investigate the impact of lead-free solder reflow on electronic component integrity. Failure analysis techniques will be used throughout the evaluation to detect failure sites and failure mechanisms. The work will also include an industrial information database on the modifications made by major packaging houses to ensure compatibility of components with lead-free soldering. Practices in Japanese electronics manufacturers and their part suppliers who have already migrated to lead-free solders will be reported.
Tracking of Lead-free Mandates: In this project, we assess selected electronic products types and establish which steps in their design, manufacturing, use, and disposal processes will be affected by the new legislation and directives, as well as by issues raised by consumer and non-governmental organizations. A report on these concerns in the US, Japan, EU, and other countries covering environmentally friendly electronics issues will be provided. This report will cover the health issues concerned with the use of toxic materials in electronics, manufacture, use, and disposal. The status of the "green electronics" movement will be discussed based on company roadmaps. The major focus of this movement at this point is on the elimination of lead from electronic products.
Contact Properties of Lead-free Coatings: Elimination of solder goes beyond permanent interconnects. Solders are also used as a non-noble finish for some connectors. It is expected that lead-free solders will also be used for separable connections. Determining the electrical characteristics of the lead-free solders is crucial. We will examine the contact resistance versus contact force characteristics for selected lead-free solders by using the CALCE Contact Resistance Probe. An appropriate aging exposure for the selected solders will be determined and the contact resistance versus contact force characteristics for the aged samples will be investigated. Fretting behavior will also be investigated and compared to the currently used tin and tin alloy systems.
For more information on the lead-free initiatives at CALCE contact our research team: Drs. Abhijit Dasgupta, Bongtae Han, Patrick McCluskey and Diganta Das at (301) 405-5323.
back to top
The Telecommunications Working Group (TWG) established within the CALCE Consortium met for the first time on December 7, 2000. The group consists of Avici Systems, Celestica, Ciena, Corvis, Ericsson, Lucent, Nokia, Nortel Networks, Philips, and Teradyne.
Participants met to discuss issues and projects of interest to the telecommunications industry. Topics included reliability of optoelectronic devices, migration in alternative finishes, radiation-induced failure mechanisms, inappropriate industry specifications, parts selection of passive optical devices, environmental sustainability of new technologies, and failure predictions that take into account non-functionality due to minute changes in resistance.
The output of this meeting was a list of candidate consortium projects that address needs of the telecom industry that have not been addressed in past or current Consortium projects. The candidate consortium projects will be modified and narrowed based on communication between the TWG and CALCE.
The next meeting of TWG is scheduled to occur during the CALCE Consortium Technical Review Meeting in March 2001. Companies interested in obtaining further information or getting involved should contact Dr. Michael Osterman at osterman@calce.umd.edu or (301) 405-8023.
back to top
The National Aeronautics and Space Administration (NASA) Electronic Parts and Packaging Program (NEPP) and CALCE have formed a collaborative partnership to conduct research and develop strategies and methodologies for selecting and evaluating electronic parts and packaging technologies on future NASA projects and missions. The NEPP/NASA program will focus on making CALCE research and software available to NASA engineers through the NEPP Information Management and Dissemination program (or 'virtual' merging of CALCE research and software with NEPP Information Management and Dissemination resources). Selected NASA engineers will undergo training at CALCE on the use and application of CALCE tools and on several strategies for improving the quality of parts selection and qualification processes and procedures.
NASA NEPP is an organization that provides a single common structure for the generation of electronic parts and packaging technology information that is broadly applicable across several NASA missions. One of its critical missions is to manage and disseminate NEPP information and supplier data to NASA engineers and scientists. NEPP initiated the Information Management and Dissemination (IMD) database to serve as a central location for the collection and dissemination of NEPP information.
For more information on the NASA/CALCE collaboration, contact Dr. Michael Osterman at osterman@calce.umd.edu or (301) 405-8023.
back to top
Texas Instruments (TI) scan test devices with 18-bit universal bus transceivers are required for the Electronic Kill Vehicle (EKV) missile made by Raytheon Systems Company. TI supplies the devices in plastic and ceramic quad flat pecks. However, these commercially available packages cannot meet the specific application requirements (e.g., weight and size) and hence Raytheon decided to custom manufacture a chip-scale PBGA package. The new package, made with wafers from TI, is being assembled by Chip Supply Inc. and tested by Amkor Test Services (formerly Integra Technologies). Raytheon turned to CALCE to qualify the part for their application. This qualification process involved determining the life-cycle environment for the part and developing a set of application-specific tests.
It has been found that contrary to common perception, the life-cycle thermal and humidity environments of the missile are benign. The application-specific qualification of electronic components ensures that all relevant failure mechanisms are addressed. What made the qualification effort for Raytheon unique is that the electrical parameter variations were tracked and qualified before and after environmental exposure.
For more information regarding chip-scale package qualification performed at CALCE and this project, contact Dr. Diganta Das at digudas@calce.umd.edu or (301) 405-5323.
back to top
Models developed by CALCE for the Advanced Embedded Passives Technology (AEPT) Consortium (NIST ATP contract) will be used as the basis for economic predictions in the National Electronics Manufacturing Initiative (NEMI) 2000 roadmap that will be released in early 2001. The model allows an application-specific economic analysis of the conversion of discrete passive components (resistors and capacitors) to integral passives that are embedded within a printed circuit board. The model performs three basic analyses: (1) board size analysis, which is used to determine board sizes, layer counts, and the number of boards that can be fabricated on a panel; (2) panel fabrication cost modeling, including a cost-of-ownership model used to determine the impact of throughput changes associated with fabricating integral passive panels; and (3) assembly modeling used to determine the cost of assembling all discrete components and their associated inspection and rework. The combination of these three analyses is used to evaluate size/cost tradeoffs for several example systems, including the NEMI hand-held emulator, a picocell board, and a fiber channel card.
For more information on CALCE embedded passive models, contact Dr. Peter Sandborn at sandborn@calce.umd.edu or (301) 405-3167. To access the members only website with a complete description of the CALCE embedded passive models go to (project C01-11).
back to top
CALCE and the Center for Energy and Environmental Resources at the University of Texas (Austin) have won a grant from the IEEE and National Science Foundation Packaging Research Center at Georgia Tech to develop web-based educational materials that address the economic impact of electronic packaging technology, specifically the process of predicting the manufacturing and life-cycle cost of electronic systems during their design and development process. A one-semester course on cost analysis for electronic systems has already been developed and taught at CALCE. The IEEE/NSF support will enable two key activities that significantly broaden the impact of this course: (1) the development and dissemination of multimedia web-based instructional materials based on the existing course for use in cost analysis courses and as supplemental materials for a broad cross-section of other courses in the electronics and electronic packaging areas; and (2) the expansion of the elements within the course that address life-cycle costs, particularly the concepts of life-cycle assessment (LCA) and design for environment (DFE).
Six Internet-based modules are being developed in the areas of process flow analysis, test economics, life-cycle concepts, quality and yield, end of life, and product sustainment.
For more information contact Dr. Peter Sandborn at
(301) 405-3167 or sandborn@calce.umd.edu.
back to top
CALCE hosted the Avionics Roadmap 2000 Conference on August 8-9, 2000. Approximately fifty-five people attended, representing a wide cross-section of the end user, airframer, and avionics communities. Companies and organizations such as Boeing, Airbus, FAA, DoD, USAF, General Dynamics, Honeywell, Rockwell, Texas Instruments, NEMI, SIA and CALCE faculty gave twenty presentations. The conference brought together senior representatives of civil and military aircraft end-users, aircraft manufacturers and suppliers, regulators and standards-setters, and component roadmappers to learn about the CALCE Avionics Roadmap. The conference addressed the urgent need of avionics companies to develop methods for using commercial technology in their products while phasing out reliance on the traditional military supply chain, which is rapidly disappearing. The topics covered included developments in systems architecture, air traffic management, open systems, supportability, semiconductor technology, and risk assessment.
The presentation materials are available to CALCE Consortium members at here. For further information on the Avionics Roadmap project, contact Chris Wilkinson at chrisw@calce.umd.edu or (301) 405-4563.
back to top
Contract outsourcing involves the transfer of specific assembly activities related to a product or process from an OEM (original equipment manufacturer) to a CA (contract assembler). This website presents industry outsourcing data from the top OEMs and CAs, step-by-step procedures for performing benchmarking, management of the CA, the economics of outsourcing, and case studies of large OEMs that have successfully performed outsourcing of electronics assembly activities.
Prior to the initiation of outsourcing, the OEM has to benchmark the available CAs and rank them for suitability based on the specific products or processes that are to be outsourced. Sources of data for benchmarking, the types of benchmarking, and the benefits of benchmarking are discussed. A detailed step-by-step procedure to carry out the benchmarking process has been developed based on interviews with leading OEMs. The economics of outsourcing is presented, along with the two primary methods of cost accounting used in the OEM industry: traditional cost accounting and activity-based costing.
Once the outsourcing decision is made, the OEM has to manage the CA in order to ensure a mutually beneficial relationship. The management of the contract assembler comprises corporate issues like maintenance of the OEM-CA relationship, corporate culture, strategic partnerships, and information technology to improve efficiency. Case studies of leading OEMs are included, based on information obtained through interviews with management at these companies and from supplemental information available in literature. Supplemental data tables and case studies of customer service and accelerated change methodology are also provided.
For more information contact Dr. Peter Sandborn at (301) 405-3167 or sandborn@calce.umd.ed. To access the members only website go to (Project C00-35).
back to top
As part of the effort to be an important resource base for the electronics and photonics industry, CALCE hosted a workshop August 22, 2000 on new strategies for ensuring reliability of printed circuit assemblies. The workshop began with an introductory presentation that reviewed the physics of failure behind the most commonly found failures in printed circuit assemblies. Later, speakers from CALCE and industry presented talks on new strategies for addressing these potential failure mechanisms, including best practices for managing supply chains, contactless in-circuit testing (ICT), fault identification using SQUID microscopy, and process improvement through the use of X-ray laminography.
Companies interested in receiving more information about this workshop or interested in attending similar events in the future should contact Dr. Michael Osterman at osterman@calce.umd.edu or (301) 405-8023.
back to top