VLSI Test Principles and Architectures: Design for Testability (Systems on Silicon)

This book is a comprehensive guide to new DFT methods that will show the readers how to design a testable and quality product, drive down test cost, improve product quality and yield, and speed up time-to-market and time-to-volume.

· Most up-to-date coverage of design for testability. 
· Coverage of industry practices commonly found in commercial DFT tools but not discussed in other books. 
· Numerous, practical examples in each chapter illustrating basic VLSI test principles and DFT architectures.
· Lecture slides and exercise solutions for all chapters are now available.
· Instructors are also eligible for downloading PPT slide files and MSWORD solutions files from the manual website.

Table of Contents

Chapter 1 - Introduction
Chapter 2 - Design for Testability
Chapter 3 - Logic and Fault Simulation 
Chapter 4 - Test Generation 
Chapter 5 - Logic Built-In Self-Test
Chapter 6 - Test Compression
Chapter 7 - Logic Diagnosis
Chapter 8 - Memory Testing and Built-In Self-Test
Chapter 9 - Memory Diagnosis and Built-In Self-Repair
Chapter 10 - Boundary Scan and Core-Based Testing
Chapter 11 - Analog and Mixed-Signal Testing
Chapter 12 - Test Technology Trends in the Nanometer Age

VLSI Test Principles and Architectures: Design for Testability

Parametric resonance has been well established in many areas of science, including the stability of ships, the forced motion of a swing and Faraday surface wave patterns on water. We have previously investigated a linear parametrically driven torsional oscillator and along with other groups have mentioned applications including mass sensing, parametric amplification, and others. Here, we thoroughly investigate the design of a highly sensitive mass sensor. The device we use to carry out this study is an in-plane parametrically resonant oscillator. We show that in this configuration, the nonlinearities (electrostatic and mechanical) have a large impact on the dynamic response of the structure. This result is not unique to this oscillator—many MEMS oscillators display nonlinearities of equal importance (including the very common parallel plate actuator). We report the effects of nonlinearity on the behavior of parametric resonance of a micro-machined oscillator. A nonlinear Mathieu equation is used to model this problem. Analytical results show that nonlinearity significantly changes the stability characteristics of parametric resonance. Experimental frequency response around the first parametric resonance is well validated by theoretical analysis. Unlike parametric resonance in the linear case, the jumps (very critical for mass sensor application) from large response to zero happen at additional frequencies other than at the boundary of instability area. The instability area of the first parametric resonance is experimentally mapped. Some important parameters, such as damping co-efficient, cubic stiffness and linear electrostatic stiffness are extracted from the nonlinear response of parametric resonance and agree very well with normal methods.

Effect of cubic nonlinearity on auto-parametrically amplified resonant MEMS mass sensor

This paper reports a high-sensitivity low-noise capacitive accelerometer system with one micro-g//spl radic/Hz resolution. The accelerometer and interface electronics together operate as a second-order electromechanical sigma-delta modulator. A detailed noise analysis of electromechanical sigma-delta capacitive accelerometers with a final goal of achieving sub-/spl mu/g resolution is also presented. The analysis and test results have shown that amplifier thermal and sensor charging reference voltage noises are dominant in open-loop mode of operation. For closed-loop mode of operation, mass-residual motion is the dominant noise source at low sampling frequencies. By increasing the sampling frequency, both open-loop and closed-loop overall noise can be reduced significantly. The interface circuit has more than 120 dB dynamic range and can resolve better than 10 aF. The complete module operates from a single 5-V supply and has a measured sensitivity of 960 mV/g with a noise floor of 1.08 /spl mu/g//spl radic/Hz in open-loop. This system can resolve better than 10 /spl mu/g//spl radic/Hz in closed-loop.

Noise analysis and characterization of a sigma-delta capacitive microaccelerometer

This paper is a review of the remarkable progress that has been made during the past few decades in design, modeling, and fabrication of micromachined resonators. Although micro-resonators have come a long way since their early days of development, they are yet to fulfill the rightful vision of their pervasive use across a wide variety of applications. This is partially due to the complexities associated with the physics that limit their performance, the intricacies involved in the processes that are used in their manufacturing, and the trade-offs in using different transduction mechanisms for their implementation. This work is intended to offer a brief introduction to all such details with references to the most influential contributions in the field for those interested in a deeper understanding of the material.

Micromachined Resonators: A Review

A new resonant accelerometer is presented consisting of a doubly clamped beam coupled to a seismic mass. The beam is thermally excited by an implanted resistor and its vibration is sensed piezoresistively. An acceleration which deflects the seismic mass leads to characteristic strains inside the resonator, shifting its resonance frequency. We studied the oscillation characteristics of the resonant beam. The non-linearity at high excitation amplitudes is treated theoretically and experimentally. Further, it is shown that the electrical and thermal cross-talk can be eliminated. The resonant sensing principle ensures a quasi-digital output signal, high sensitivity and a mechanical integrity test. Advanced automotive safety systems and x-by wire applications require a high reliability of the employed sensors. The sensor presented here allows an on-going self-test without any constructive changes of the sensor element. The self-test concept, we developed also finds applications in other sensors with resonant structures.

Resonant accelerometer with self-test

The measurement of angular rate and linear acceleration are widely used in automotive systems [1,2]. In all present applications and even more in future „x-by-wire” steering systems sensor errors or undetected sensor failures may have serious consequences. In order to achieve a higher degree of sensor safety we developed a new self-test concept for resonant structure sensors [3]. It is expected to fulfil the following conditions: no influence of the self-test on the measurement, measuring signal and test signal are simultaneous and time-continuous, a certain calibration of the sensor is possible, the self-test covers the whole measurement and dynamic range of the sensor, the self-test signal couples to the mechanical structure of the sensor and no constructive changes of the sensor element are necessary. We present properties of this self-test applied to a tuning fork angular rate sensor [4,5] and a resonant accelerometer [6]. A self-test circuit generates a special test-signature, which is applied to the actuating elements in order to generate an additional vibration on the read-out structure of the sensor. This produces an effect both equivalent to and separable from the physical quantity to be measured. This effect of the test signature on the sensor is measured and compared with the initial test signature. An intolerable deviation from the expected behaviour activates the sensor-failure-signal.

Self-Test for Resonant Structure Sensors Applied to a Tuning Fork Gyro and a Resonant Accelerometer

In this contribution an overview concerning the design, fabrication and performance of a new generation of micromachined silicon accelerometers will be given.

A New Generation of Micromachined Accelerometers For Airbag Applications

The sensor has a selection oscillator (24) with tines (21a, 21b) that are arranged at a distance and connected with each other by a base (22). A bar (13) connects an excitation oscillator (11) with the base of the oscillator (24), and piezoelectric films (12a, 12b) are provided. The excitation (11) moves around a bar axis (15) during torsion oscillation, so that the base oscillates around the axis such that the tines are moved in a direction radial to the axis based on coriolis force. A direct voltage is applied to the oscillator (11) that is provided with electrodes.

Angular rate sensor for vehicle, has selection oscillator with tines that are arranged at distance and are connected with each other by base, where direct voltage is applied to excitation oscillator that is provided with electrodes

Inertial Measurement Units (IMU) for upcoming automotive chassis control systems require sensor clusters with multi-axial sensors for acceleration and angular rate. In this paper, we present a low-g accelerometer that fits the IMU requirements for advanced automotive applications and is capable of monolithic multiple-axes integration. For the target application a high offset stability and an over-critical damping of the sensing element are required. With simple design changes the squeezed-film damping of the sensor can be adjusted within a wide range (5 Hz to 400 Hz) using atmospheric pressure inside the cavity. Due to its symmetrical design and the differential readout principle, an offset drift of less than 50mg over the full temperature range (-40°C … 120°C) was achieved. The sensor principle presented in this paper can be utilized to realize a sensitivity axis parallel to the wafer surface as well as perpendicular to the surface. Furthermore, monolithic integration into a two-axis (x/z) or a three-axis (x/y/z) sensing element is possible. The tri-axial element exhibits a four-mass design providing redundancy and thus an ongoing self-test capability. Inertial Measurement Units (IMU) for upcoming automotive chassis control systems require sensor clusters with multi-axial sensors for acceleration and angular rate. In this paper, we present a low-g accelerometer that fits the IMU requirements for advanced automotive applications and is capable of monolithic multiple-axes integration. For the target application a high offset stability and an over-critical damping of the sensing element are required. With simple design changes the squeezed-film damping of the sensor can be adjusted within a wide range (5 Hz to 400 Hz) using atmospheric pressure inside the cavity. Due to its symmetrical design and the differential readout principle, an offset drift of less than 50mg over the full temperature range (-40°C … 120°C) was achieved. The sensor principle presented in this paper can be utilized to realize a sensitivity axis parallel to the wafer surface as well as perpendicular to the surface. Furthermore, monolithic integration into a two-axis (x/z) or a three-axis (x/y/z) sensing element is possible. The tri-axial element exhibits a four-mass design providing redundancy and thus an ongoing self-test capability.

M. Aikele

Papers

Resonant accelerometer with self-test

Self-Test for Resonant Structure Sensors Applied to a Tuning Fork Gyro and a Resonant Accelerometer

A New Generation of Micromachined Accelerometers For Airbag Applications

Angular rate sensor for vehicle, has selection oscillator with tines that are arranged at distance and are connected with each other by base, where direct voltage is applied to excitation oscillator that is provided with electrodes

A Low-g Accelerometer for Inertial Measurement Units A Low-g Accelerometer for Inertial Measurement Units