Thermal analysis automation system for semiconductor package

A physical model is presented that describes mechanisms for operating-equipment junction-to-ambient thermal resistance in excess of a typical component manufacturer's data-sheet value by as much as a factor of four under constant cooling conditions. The model accounts for the discrepancy between system thermal performance of a package and data-sheet thermal resistance value which are not accompanied by qualifying data in the form of junction-to-header thermal resistance, board temperature rise over ambient, convection coefficient, mounting sensitivity, and power dissipation. The eight constants used to predict inherent increases in package thermal resistance when going from the data-sheet-specified operating conditions to the excess-value conditions are described. These constants and procedures for obtaining them are given for dual in-line packages (DIPs), pin-grid arrays (PGAs), small-outline transistors (SOTs), and plastic leaded chip carriers (PLCCs). >

Software Engineering: A Methodical Approach (Second Edition) provides a comprehensive, but concise introduction to software engineering. It adopts a methodical approach to solving software engineering problems, proven over several years of teaching, with outstanding results. The book covers concepts, principles, design, construction, implementation, and management issues of software engineering. Each chapter is organized systematically into brief, reader-friendly sections, with itemization of the important points to be remembered. Diagrams and illustrations also sum up the salient points to enhance learning. Additionally, the book includes the author’s original methodologies that add clarity and creativity to the software engineering experience. New in the Second Edition are chapters on software engineering projects, management support systems, software engineering frameworks and patterns as a significant building block for the design and construction of contemporary software systems, and emerging software engineering frontiers. The text starts with an introduction of software engineering and the role of the software engineer. The following chapters examine in-depth software analysis, design, development, implementation, and management. Covering object-oriented methodologies and the principles of object-oriented information engineering, the book reinforces an object-oriented approach to the early phases of the software development life cycle. It covers various diagramming techniques and emphasizes object classification and object behavior. The text features comprehensive treatments of: Project management aids that are commonly used in software engineering An overview of the software design phase, including a discussion of the software design process, design strategies, architectural design, interface design, database design, and design and development standards User interface design Operations design Design considerations including system catalog, product documentation, user message management, design for real-time software, design for reuse, system security, and the agile effect Human resource management from a software engineering perspective Software economics Software implementation issues that range from operating environments to the marketing of software Software maintenance, legacy systems, and re-engineering This textbook can be used as a one-semester or two-semester course in software engineering, augmented with an appropriate CASE or RAD tool. It emphasizes a practical, methodical approach to software engineering, avoiding an overkill of theoretical calculations where possible. The primary objective is to help students gain a solid grasp of the activities in the software development life cycle to be confident about taking on new software engineering projects.

When a surface-mounted ceramic chip carrier is subjected to thermal cycling, complex stresses and strains are generated in the solder joints. Using strain gauges along with some simple assumptions, we can indirectly measure the shear strain and shear force during these cycles. The force, the strain, and the temperature are related by a Simple linear equation with calculable coefficients. At any temperature, the solder simultaneously undergoes creep and relaxation in a process We call stress reduction.'' The rate of reduction is controlled by the conventional constitutive relation in which the rate of change of shear strain at a given temperature is proportional to the shear raised to a constant power. The constitutive relation is used to develop an equation for as a function of time during isothermal stress, reduction. Experiments confirm this equation over the ,range of -28 tO 97°C. The measured time to half-stress depends on the initial stress. For typical values it was measured as 10 min to 1 h at 97°C, one month at 33°c, and (by extrapolation) 30 Years at - 28°C. Almost all methods for interpreting metal fatigue involve the strain amplitude during cycling. In temperature cycling the shear strain amplitude can be expressed as (BS/ H) \triang \alpha T, where S is the in-plane distance from the center of the carrier to the solder joint, H is the height of the solder joint, \triang \alpha is the expansivity difference and AT is the temperature amplitude. The parameter B is a solder Compliance factor. For small temperature amplitudes, B approaches unity at high temperatures and is 0.8 at 100°C, · but it is only 0.08 at 0°C Thus the ratio between the strain amplitude and temperature amplitude depends on the temperature, and this must be factored into any theory Which is used to explain thermal cycle, fatigue in solder joints of surface-mounted leadless chip carriers.

The Software design process involves a high degree of human interaction and design artifacts creation by software engineers. Software designers use their experience to make assumptions and decisions. Therefore, the software design is prone to errors that lead to a bad quality software. Software engineering literature focuses on software errors and failures. This research relates the concept of human and organizational errors to the errors committed by software engineers during the software design phase to improve software quality. The authors performed a systematic literature review (SLR) of the software engineering to identify software design errors and later classify them. The outcome is a software design errors taxonomy that provides errors and a way to classify those errors based on their similarities and origin. This research proposes a guide to comprehend common software design errors. The guide will allow software engineers to focus and create robust software design. The guide also provides a structured approach to detect software design errors upfront during the software design inspection process. Software development organizations can use this awareness to develop countermeasures to help with error prevention, thereby improving the overall software quality.

The problems associated with the direct attachment of leadless ceramic chip carriers (LCCCs) to conventional PWB structures subjected to ambient thermal and power (on/off) cycling are now widely documented. The reliability of LCCCs mounted on various novel substrate materials has been assessed here during ambient thermal cycling from −55° to 125°C and −20° to +70°C and during power heat cycling. Polyimide Kevlar material was rejected on the basis that microcracks, formed in the laminate during thermal cycling, propagated to the surface and resulted in copper track breakages. A flexible laminate interconnection structure for strain relief was found to be too cumbersome for most applications and gave only a small reliability improvement. Polyimide quartz and copper‐invar‐copper cored materials were both found to give a high degree of reliability in thermal cycling. The metal cored laminate is preferred because it is also a more rigid structure with the better thermal conductance needed for many high performance and reliability applications. An elastomer coated FR4 material also performed well during lower temperature thermal and power cycling tests and represents a reduced cost option for less severe environments.

Automation is in most cases done through the use of hardware and software. Software-related costs account for a growing share of total development costs for automation systems. In the automation field, containment of software costs can be done either through the use of model-based tools (e.g., Matlab) or through a higher level of reuse. This chapter argues that both technologies have their place. The first strategy can be used for the design of software for a large number of identical installations or for the implementation of only part of the software (i.e., the control algorithms). The second strategy is advantageous in the case of industrial automation systems targeting niche markets where systems tend to be one-of-a-kind and where they can be organized in families of related applications. In many applications, a combination of the two approaches will produce the best results. Both approaches are treated in the paper. The main focus of the chapter is on developing software for automation. As such software will often be implemented for slightly different processes, it is highly appropriate that the production process is at least partly automated. As space is limited, this chapter can not cover all aspects of the design and implementation of software for automation, but we claim that the methods discussed here integrate very well with traditional methods of software and systems engineering. Experience from contributions to various research projects recently performed at Swiss Federal Technical university (ETH) are also summarized.

In the current work, we have extended our past studies on Flip Chip Ceramic Ball Grid Array (FC-BGA) microprocessor packaging configurations to investigate in-situ die stress variation during thermal and power cycling. The utilized (111) silicon sensor rosettes were able to measure the complete three-dimensional stress state (all 6 stress components) at each sensor site being monitored by the data acquisition hardware. The test chips had dimensions of 20 × 20 mm, and 3600 lead free solder interconnects (full area array) were used to connect the chips to high CTE ceramic chip carriers. A unique package carrier was developed to allow measurement of the die stresses in the FC-CBGA components under thermal and power cycling loads without inducing any additional mechanical loadings. Initial experiments consisted of measuring the die stress levels while the components were subjected to a slow (quasi-static) temperature changes from 0 to 100 C. In later testing, long term thermal cycling of selected parts was performed from 0 to 100 C (40 minute cycle, 10 minute ramps and dwells). After various durations of cycling, the sensor resistances at critical locations on the die device surface (e.g. die center and die corners) were recorded. From the resistance data, the stresses at each site were calculated and plotted versus time. Finally, thermal and power cycling of selected parts was performed, and in-situ measurements of the transient die stress variations were performed. Power cycling was implemented by exciting the on-chip heaters on the test chips with various power levels. During the thermal/power cycling, sensor resistances at critical locations on the die device surface (e.g. die center and die corners) were recorded continuously. From the resistance data, the stresses at each site were calculated and plotted versus time.

The article describes an approach to the creation of an experience base for a software design organization, which is focused on its application in the development of software-intensive automated systems (AS). The use of the proposed experience base extends the potential of the OwnWIQA tool-modeling environment in the workplace of a member of the software design team. The specificity of the toolkit includes the design of a reusable model (precedent model) in the process of work execution on the design of an AS, which is included in the experience base for the purpose of its further use in the development of AS or the creation of a new AS from the same family. The article describes the knowledge base model of software projects, tools for finding use cases, implemented in the OwnWIQA environment. Experimental studies are described that reveal the parameters of precision and recall for a precedent search in the knowledge base. The factors influencing these indicators for different users of the system are given. The article may be of interest to specialists in the field of building knowledge and experience bases.

In this paper, the thermal performance analysis and optimization of the package of a specific multi-heat source power device is carried out. Firstly, the finite element analysis software ANSYS Icepak is used as a tool to build a simplified model of the array type multi-power device package module. Secondly, the impact of five variable parameters on thermal performance of multi-heat source power devices is analyzed. These parameters are chip size, chip power consumption, die attach material, packaging material, package size. Finally, through the orthogonal test analysis method, the junction temperature and thermal resistance of the package are selected as the test indexes, and five parameters are selected as the orthogonal test factors to analyze the influence of the five parameters on the thermal performance. The results show that the thermal conductivity of the die attach material is most significant regardless of the package junction temperature or thermal resistance. By summarizing the influence of various factors on the thermal performance of power devices, the suggestions for optimizing the thermal performance of multi-heat source power devices are proposed. The results obtained have important guiding significance for the thermal performance optimization of power devices.

There is a critical need for timely and usable curriculum development materials for teaching user interface development to software engineering and computer science students. An updated version of the Software Engineering Institute's curriculum module on User Interface Development has been released. This paper provides an overview of the module, its history, and how it has been used.At the Software Engineering Institute (SEI) at Carnegie-Mellon University there is a Curriculum Development Project as part of the Education Program (Gibbs, 1989). A major goal of the curriculum development project is to devise model curricula and support-materials for teaching all topics in software engineering. For topics such as unit testing, software design, requirements analysis, and so on, there are curriculum modules to help teachers prepare courses. I have written, and recently revised, a module on User Interface Development (Perlman, 1989b), described in detail below. It has proven to be useful to all people interested in the teaching of user interface development to software engineers. Some of my experiences with the module are summarized in Perlman (1988).The module is not a book nor a course, but contains information to help others prepare short- or full-term courses on user interface development.

Putting Requirements and Quality at the Core of Global Service Delivery: Current Efforts and Future Plans at Pace University

This proposal is about a study we recently published in the IEEE Transaction of Software Engineering journal [4]. Context: Collaborative software engineering (CoSE) deals with methods, processes and tools for enhancing collaboration, communication, and co-ordination (3C) among team members [5]. CoSE can be employed to conceive different kinds of artifacts during the development and evolution of software systems. For instance, when focusing on software design, multiple stakeholders with different expertise and responsibility collaborate on the system design. Model-Driven Software Engineering (MDSE) provides suitable techniques and tools for specifying, manipulating, and analyzing modeling artifacts including metamodels, models, and transformations [1]. Collaborative MDSE consists of methods or techniques in which multiple stakeholders manage, collaborate, and are aware of each others' work on a set of shared models. A collaborative MDSE approach is composed of three main complementary dimensions: (i) a model management infrastructure for managing the life cycle of the models, (ii) a set of collaboration means for allowing involved stakeholders to work on the modelling artifacts collaboratively, and (iii) a set of communication means for allowing involved stakeholders to exchange, share, and communicate information within the team. Collaborative MDSE is attracting several research efforts from different research areas (e.g., model-driven engineering, global software engineering, etc.), resulting in a variegated scientific body of knowledge on the topic. Objective: In this study we aim at identifying, classifying, and understanding existing collaborative MDSE approaches. More specifically, our goal is to assess (i) the key characteristics of collaborative MDSE approaches (e.g., model editing environments, model versioning mechanisms, model repositories, support for communication and decision making), (ii) their faced challenges and limitations, and (iii) the interest of researchers in collaborative MDSE approaches over time and their focus on the three dimensions of collaborative MDSE. Method: In order to achieve this, we designed and conducted a systematic mapping study [6] on collaborative MDSE. Starting from over 3,000 potentially relevant studies, we applied a rigorous selection procedure [3] resulting in 106 selected papers, further clustered into 48 primary studies, along a time span of nineteen years. A suitable classification framework has been empirically defined and rigorously applied for extracting key information from each selected study. We collated, summarized, and analyzed extracted data by applying scientifically sound data synthesis techniques. Results: In addition to a number of specific insights, our analysis revealed the following key findings: (i) there is a growing scientific interest on collaborative MDSE in the last years; (ii) multi-view modeling, validation support, reuse, and branching are more rarely covered with respect to other aspects about collaborative MDSE; (iii) different primary studies focus differently on individual dimensions of collaborative MDSE (i.e., model management, collaboration, and communication); (iv) most approaches are language-specific, with a prominence of UML-based approaches; (v) few approaches support the interplay between synchronous and asynchronous collaboration. Conclusion: This study gives a solid foundation for a thorough identification and comparison of existing and future approaches for collaborative MDSE [2]. Those results can be used by both researchers and practitioners for identifying existing research/technical gaps to attack, better scoping their own contributions to the field, or better understanding or refining existing ones.

Software engineering (SE) educators are challenged to balance the scope and depth in their courses to train students in skills which will fulfill the ever-evolving industry needs. Capstone courses are a tool for educators to transfer hands-on experience into practical knowledge and skills of SE students. This paper describes the design of a Casptone course, at Lappeenranta University of Technology. The designed course is human-centric SE capstone, infusing design thinking methods and agile practices into the project life-cycle knowhow. The capstone was offered in spring of 2017 as a 16-week course for 29 students. Design thinking was effective to perform requirement elicitation, software design and testing. Also, the applied approach allowed students to be self-directed which increased their motivation, as a result there was zero dropout rate. Design thinking is a powerful mean of problem solving and effectively supports SE education in bringing a more hands-on and minds-on, problem-based curriculum.

Modern systems are critically dependent on software for their design and operation. The next generation of developers must be facile in the specification, design and implementation of dependable software using rigorous developmental processes. To help prepare this generation we have developed a teaching approach and materials that serve a two-fold purpose: promote an understanding and appreciation of the discrete mathematical structures (DM) that are the foundation of software engineering (SE) theory; and provide motivation and training of modern software development and analysis tools. Our teaching approach and materials form a two-course sequence establishing mastery of important SE areas: DM underlying modern SE theory (e.g., static analysis and proof); formal languages and their use (e.g., software specification languages); application of DM to SE (e.g., composition of theory and application for artifact development); and mathematics for advanced SE engineering needs (e.g., finite state machines and graph theory)

Advances in software engineering and their relations to pattern recognition and image processing