Materials for high-density electronic packaging and interconnection

Electronic packaging and interconnections are the elements that today limit the ultimate performance of advanced electronic systems. Materials in use today and those becoming available are critically examined to ascertain what actions are needed for U.S. industry to compete favorably in the world market for advanced electronics. Materials and processes are discussed in terms of the final properties achievable and systems design compatibility. Weak points in the domestic industrial capability, including technical, industrial philosophy, and political, are identified. Recommendations are presented for actions that could help U.S. industry regain its former leadership position in advanced semiconductor systems production

Design automation and analysis of three-dimensional integrated circuits

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 165-176).This dissertation concerns the design of circuits and systems for an emerging technology known as three-dimensional integration. By stacking individual components, dice, or whole wafers using a high-density electromechanical interconnect, three-dimensional integration can achieve scalability and performance exceeding that of conventional fabrication technologies. There are two main contributions of this thesis. The first is a computer-aided design flow for the digital components of a three-dimensional integrated circuit (3-D IC). This flow primarily consists of two software tools: PR3D, a placement and routing tool for custom 3-D ICs based on standard cells, and 3-D Magic, a tool for designing, editing, and testing physical layout characteristics of 3-D ICs. The second contribution of this thesis is a performance analysis of the digital components of 3-D ICs. We use the above tools to determine the extent to which 3-D integration can improve timing, energy, and thermal performance. In doing so, we verify the estimates of stochastic computational models for 3-D IC interconnects and find that the models predict the optimal 3-D wire length to within 20% accuracy. We expand upon this analysis by examining how 3-D technology factors affect the optimal wire length that can be obtained. Our ultimate analysis extends this work by directly considering timing and energy in 3-D ICs. In all cases we find that significant performance improvements are possible. In contrast, thermal performance is expected to worsen with the use of 3-D integration. We examine precisely how thermal behavior scales in 3-D integration and determine quantitatively how the temperature may be controlled during the circuit placement process. We also show how advanced packaging(cont.) technologies may be leveraged to maintain acceptable die temperatures in 3-D ICs. Finally, we explore two issues for the future of 3-D integration. We determine how technology scaling impacts the effect of 3-D integration on circuit performance. We also consider how to improve the performance of digital components in a mixed-signal 3-D integrated circuit. We conclude with a look towards future 3-D IC design tools.by Shamik Das.Ph.D

Parallel Computers and Complex Systems

We present an overview of the state of the art and future trends in high performance parallel and distributed computing, and discuss techniques for using such computers in the simulation of complex problems in computational science. The use of high performance parallel computers can help improve our understanding of complex systems, and the converse is also true --- we can apply techniques used for the study of complex systems to improve our understanding of parallel computing. We consider parallel computing as the mapping of one complex system --- typically a model of the world --- into another complex system --- the parallel computer. We study static, dynamic, spatial and temporal properties of both the complex systems and the map between them. The result is a better understanding of which computer architectures are good for which problems, and of software structure, automatic partitioning of data, and the performance of parallel machines

Optimal digital system design in deep submicron technology

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 165-174).The optimization of a digital system in deep submicron technology should be done with two basic principles: energy waste reduction and energy-delay tradeoff. Increased energy resources obtained through energy waste reduction are utilized through energy-delay tradeoffs. The previous practice of obliviously pursuing performance has led to the rapid increase in energy consumption. While energy waste due to unnecessary switching could be reduced with small increases in logic complexity, leakage energy waste still remains as a major design challenge. We find that fine-grain dynamic leakage reduction (FG-DLR), turning off small subblocks for short idle intervals, is the key for successful leakage energy saving. We introduce an FG-DLR circuit technique, Leakage Biasing, which uses leakage currents themselves to bias the circuit into the minimum leakage state, and apply it to primary SRAM arrays for bitline leakage reduction (Leakage-Biased Bitlines) and to domino logic (Leakage-Biased Domino). We also introduce another FG-DLR circuit technique, Dynamic Resizing, which dynamically downsizes transistors on idle paths while maintaining the performance along active critical paths, and apply it to static CMOS circuits.(cont.) We show that significant energy reduction can be achieved at the same computation throughput and communication bandwidth by pipelining logic gates and wires. We find that energy saved by pipelining datapaths is eventually limited by latch energy overhead, leading to a power-optimal pipelining. Structuring global wires into on-chip networks provides a better environment for pipelining and leakage energy saving. We show that the energy-efficiency increase through replacement with dynamically packet-routed networks is bounded by router energy overhead. Finally, we provide a way of relaxing the peak power constraint. We evaluate the use of Activity Migration (AM) for hot spot removal. AM spreads heat by transporting computation to a different location on the die. We show that AM can be used either to increase the power that can be dissipated by a given package, or to lower the operating temperature and hence the operating energy.by Seongmoo Heo.Ph.D

A low ground bounce CMOS off-chip driver design

With the advancement of technology, submicron CMOSonly process is available now for Application Specific Integrated Circuits (ASICs). The high integration leads to the need for high pin counts. However voltage supply and ground bounce due to many output drivers switching at the same time is becoming a major problem. In this thesis, a CMOS offchip buffer design which generates ECL logic levels with lower ground bounce noise is described and demonstrated. The technique used in designing this buffer to reduce voltage noise differs from conventional design techniques. Traditionally there are two general methods to reduce ground bounce. One approach tries to reduce the instantaneous current change (di/dt) by increasing (prolonging) the rise and fall time of the signals. The other approach attempts to reduce the parasitic inductance attributed to packaging by using multiple supply pins. Our technique reduces the voltage noise by controlling the instantaneous current change through the reduction of current difference during switching time. Based on this approach, a novel circuit structure is designed. This circuit has a fully symmetrical configuration and is being selfbiased through negative feedback. A current injection technique is also used to increase the stability of the circuit. SPICE simulation of the proposed circuit is performed. Comparison and tradeoffs with other approaches are studied

A serial bus architecture for parallel processing systems.

One of the most serious deterrants to the development of multiple processor architectures has been the problem of providing adequate communication between the discrete processing elements. This paper examines two communications-based constraints. The first constraint is related to the physical structure of the VLSI chip. The wider the communication path the more pins are needed to effect the data transfer. As Integrated Circuits grow in computational power, more communication capacity is needed, pushing designs closer to the pin limitations of the packaging technology. The second constraint, somewhat related to the first, is the limited speed with which data can be transmitted via internal channels. Typical speeds one can achieve on a single wire are on the order of 1 Gbps. The recent development of an Optoelectronic Multiplexer may allow VLSI chips to communicate at rates up to 7 Gbps. An architecture for a parallel processing computer which takes advantage of this new capability is presented. The feasibility of a single-chip parallel-processor based on the Optoelectronic Multiplexer is examined by projecting current trends in processor speed, power, and transistor count into estimates of throughput for a multi-processor IC.http://hdl.handle.net/10945/22094http://archive.org/details/serialbusarchite00delaLieutenant, United States NavyApproved for public release; distribution is unlimited