On testing VLSI chips for the big Viterbi decoder

A general technique that can be used in testing very large scale integrated (VLSI) chips for the Big Viterbi Decoder (BVD) system is described. The test technique is divided into functional testing and fault-coverage testing. The purpose of functional testing is to verify that the design works functionally. Functional test vectors are converted from outputs of software simulations which simulate the BVD functionally. Fault-coverage testing is used to detect and, in some cases, to locate faulty components caused by bad fabrication. This type of testing is useful in screening out bad chips. Finally, design for testability, which is included in the BVD VLSI chip design, is described in considerable detail. Both the observability and controllability of a VLSI chip are greatly enhanced by including the design for the testability feature

Developing VLSI Curricula in Electrical and Computer Engineering Department

© ASEE 2010VLSI (Very Large Scale Integrated Circuits) technology has enabled the information technology revolution which greatly changed the life style of human society. Computers, internet, cellphones, digital cameras/camcorders and many other consumer electronic products are powered by VLSI technology. In the past decades, the VLSI industry was constantly driven by the miniaturization of transistors. As governed by Moore’s law, the number of transistors in the same chip area has been doubled every 12 to 18 months. Nowadays, a typical VLSI CPU chip can contain millions to billions of transistors. As a result, the design of VLSI system is becoming more and more complex. Various EDA tools must be used to help the design of modern VLSI chips. The semiconductor and VLSI industry remain strong needs for VLSI engineers each year. In this paper, efforts in developing systematic VLSI curricula in Electrical and Computer Engineering department have been proposed. The goal of the curricula is to prepare students to satisfy the growing demands of VLSI industry as well as the higher education/research institutions. Modern VLSI design needs a thorough understanding about VLSI in device, gate, module and system levels. We developed CPEG/EE 448D: Introduction to VLSI to give students a comprehensive introduction about digital VLSI design and analysis. In this course, various EDA tools (such as Mentor Graphics tools, Cadence PSPICE, Synopsys) are used in the course projects to help students practice the VLSI design. In addition, analog and mixed signal circuit design are becoming more and more important as MEMS (Microelectromechanical Systems) and Nano devices are integrated with VLSI into Systemon-Chip (SoC) design. We developed CPEG/EE 458: Analog VLSI to introduce the analog and mixed signal VLSI design. As portable electronics (e.g. laptops, cellphones, PDAs, digital cameras) becoming more and more popular, low power VLSI circuit design is becoming a hot field. We developed CPEG/EE 548: Low Power VLSI Circuit Design to introduce various low power techniques to reduce the power consumption of VLSI circuits. Nowadays the VLSI circuits can contain billions of transistors, the testing of such complex system becoming more and more challenging. We developed CPEG/EE 549: VLSI Testing to introduce various VLSI testing strategies for modern VLSI design. In addition to the design and testing, we also developed EE 448: Microelectronic Fabrication to introduce the fabrication processes of modern VLSI circuits. With such a series of VLSI related curricula, students have an opportunity to learn comprehensive knowledge and hands-on experience about VLSI circuit design, testing, fabrication and EDA tools. Students demonstrate tremendous interests in the VLSI field, and all the VLSI courses are generally oversubscripted by students in the early stage of enrollment. Many students are also doing the VLSI graduate research and published various papers/posters in the VLSI related journals/conferences

VLSI Testing and Test Power

This paper first reviews the basics of VLSI testing, focusing on test generation and design for testability. Then it discusses the impact of test power in scan testing, and highlights the need for low-power VLSI testing.2011 International Green Computing Conference and Workshops (IGCC 2011), July 25-28, 2011, Orlando, FL, US

Power-Aware Testing For Low-Power VLSI Circuits

Low-power VLSI circuits are indispensable for almost all types of modern electronic devices, from battery-driven mobile gadgets to harvested-energy-driven wireless sensor systems. However, the testing of such low-power VLSI circuits has become a big challenge, especially due to the excessive power dissipation during scan testing. This paper will highlight three major test-power-induced problems (namely heat, false failures, clock stretch) and describe how to mitigate them with power-aware VLSI testing. Future research topics in this field will also be discussed.13th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT-2016), 25-28 October 2016, Hangzhou, Chin

Programmable latching probe microstructures for wafer testing applications

The objective of this thesis is to design a programmable wafer testing array on a single chip based on micro electromechanical systems (MEMS) and VLSI. The wafer-scale integration in this thesis is a programmable array of test probes that are used for engineering test of VLSI and ULSI silicon integrated circuits at the wafer level. This consists of two subsystems (1) the VLSI address circuits used for addressing and controlling the MEMS on the chip and (2) the latching probe MEMS microstructure array that actuates into position for testing VLSI wafers. Each of the subsystems have been designed, analyzed and simulated separately. These structures were then integrated into a demonstration 4x4 array forming a programmable probe card. A 3-micrometer critical dimension is used for both the VLSI CMOS and the MEMS physical design layouts. The fabrication technique for the MEMS microstructure is detailed. A standard 12-mask CMOS technology is used for the fabrication of the address circuits

Quiescent current testing of CMOS data converters

Power supply quiescent current (IDDQ) testing has been very effective in VLSI circuits designed in CMOS processes detecting physical defects such as open and shorts and bridging defects. However, in sub-micron VLSI circuits, IDDQ is masked by the increased subthreshold (leakage) current of MOSFETs affecting the efficiency of I¬DDQ testing. In this work, an attempt has been made to perform robust IDDQ testing in presence of increased leakage current by suitably modifying some of the test methods normally used in industry. Digital CMOS integrated circuits have been tested successfully using IDDQ and IDDQ methods for physical defects. However, testing of analog circuits is still a problem due to variation in design from one specific application to other. The increased leakage current further complicates not only the design but also testing. Mixed-signal integrated circuits such as the data converters are even more difficult to test because both analog and digital functions are built on the same substrate. We have re-examined both IDDQ and IDDQ methods of testing digital CMOS VLSI circuits and added features to minimize the influence of leakage current. We have designed built-in current sensors (BICS) for on-chip testing of analog and mixed-signal integrated circuits. We have also combined quiescent current testing with oscillation and transient current test techniques to map large number of manufacturing defects on a chip. In testing, we have used a simple method of injecting faults simulating manufacturing defects invented in our VLSI research group. We present design and testing of analog and mixed-signal integrated circuits with on-chip BICS such as an operational amplifier, 12-bit charge scaling architecture based digital-to-analog converter (DAC), 12-bit recycling architecture based analog-to-digital converter (ADC) and operational amplifier with floating gate inputs. The designed circuits are fabricated in 0.5 μm and 1.5 μm n-well CMOS processes and tested. Experimentally observed results of the fabricated devices are compared with simulations from SPICE using MOS level 3 and BSIM3.1 model parameters for 1.5 μm and 0.5 μm n-well CMOS technologies, respectively. We have also explored the possibility of using noise in VLSI circuits for testing defects and present the method we have developed

The Fifth NASA Symposium on VLSI Design

The fifth annual NASA Symposium on VLSI Design had 13 sessions including Radiation Effects, Architectures, Mixed Signal, Design Techniques, Fault Testing, Synthesis, Signal Processing, and other Featured Presentations. The symposium provides insights into developments in VLSI and digital systems which can be used to increase data systems performance. The presentations share insights into next generation advances that will serve as a basis for future VLSI design

Particle Swarm Optimization Framework for Low Power Testing of VLSI Circuits

Power dissipation in sequential circuits is due to increased toggling count of Circuit under Test, which depends upon test vectors applied. If successive test vectors sequences have more toggling nature then it is sure that toggling rate of flip flops is higher. Higher toggling for flip flops results more power dissipation. To overcome this problem, one method is to use GA to have test vectors of high fault coverage in short interval, followed by Hamming distance management on test patterns. This approach is time consuming and needs more efforts. Another method which is purposed in this paper is a PSO based Frame Work to optimize power dissipation. Here target is to set the entire test vector in a frame for time period 'T', so that the frame consists of all those vectors strings which not only provide high fault coverage but also arrange vectors in frame to produce minimum toggling