1,720,968 research outputs found
The Resistance Decay after Electromigration as the Effect of Mechanical Stress Relaxation
No full textResistance decay after electromigration as the effect of mechanical stress relaxation
No full textResistance decay has been observed in Aluminum narrow lines when the high stressing current in electromigration tests is turned off. It has been interpreted as the consequence of the relaxation of eleetromigration-induced mechanical strese
Activation energy in the early stage of electromigration in Al-1% Si/TiN/Ti bamboo lines
No full textThe activation energy of electromigration in 'bamboo'-type, passivated Al-I%SMNfri lines was determined by means of high resolution resistance measurements at wafer level. Both the veiy early stages, with a nonlinear behaviour of the resistance, and the subsequent stages, characterized by an approximate!y constant rate of resistance change, were analysed with an existing model that correlates electromigration and mechanical stress evolution. An activation energy could be extracted only in the phase of linear resistance increase, where a value of 0.95 eV was found. Diffusion at the interface between AlSi and the barrier metal or the passivation could be responsible for this value of the activation energy
Activation Energy of the Early Stages of Electromigration in Al-1%Si/TiN/Ti Bamboo Lines
No full textThe activation energy of electromigration
in "bamboo" type, passivated Al-1\%Si/TiN/Ti lines was determined by means of high-resolution resistance measurements at wafer level. Both very early stages, with a non linear behaviour of the resistance, and following stages, characterized by an approximately constant rate of resistance change, were analyzed with an existing model that correlates electromigration and mechanical stress evolution. An activation energy could be extracted only in the phase of linear resistance increase, where a value of 0.95eV was found. Diffusion at the interface between Al-Si and the barrier metal or the passivation could be responsible for this value of the activation energy
The Evaluation of the True Test Temperature During Wafer-Level Electromigration Tests
No full textThe correct evaluation of the test temperature is an extremely important task when performing electromigration (EM) experiments on metal lines. In fact, reliable values of activation energy for the EM mechanism can be obtained from experimental data if and only if the true value of the temperature of each test structure during the tests is known. On the other hand true temperature measurements involve more than one practical and theoretical difficulties, ranging from heating due to Joule effect to bad thermal coupling between the test devices and the temperature sensors.
In this work a method is presented for true temperature evaluation of the test stripes during electromigration median-time-to-failure tests performed at the wafer level. In particular the problem of the thermal coupling between two or more samples tested at the same time is examined.
The experimental setup for simultaneous wafer-level testing of more than one stripe, requiring a probe-card and a switching matrix, is described, along with the development of a procedure for the calculation of the true temperature of each stripe, which takes into account Joule self-heating and mutual heating of the samples. Results obtained on Al-Si and Al-Si/TiN/Ti metallizations are shown and design guidelines to avoid thermal coupling of the samples, thus allowing more reliable temperature measurements, are provided
Limitations in NIST Test Structures when Used for Electromigration Tests of Bamboo Metal Lines
No full textDrawbacks to using NIST electromigration test-structures to test bamboo metal lines
No full textIn this work the applicability of NIST electromigration
test patterns when used to test “bamboo” metal lines is discussed. Wafer level tests on passivated and nonpassivated samples employing the AI-1 %Si/TiN/Ti metallization scheme were performed. Straight metal lines 1000 pm long and 0.9 um or 1.4 um wide were tested at two different current densities, j = 3 MA/cm2 and j = 4.5 MA/cm2, keeping the stress temperature at T = 230°C. The failures occurred mainly in the end segment areas and hindered the evaluation of the electromigration resistance of the test lines. In order to avoid this problems, completely different test patterns containing a number of geometrical variations should be defined
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
