M Corp (United States)

Voids in copper lines are a common failure mechanism in the back end of line (BEOL) of integrated circuits manufacturing, affecting chip yield and reliability. As subsequent process nodes continue to shrink metal line dimensions, monitoring and control of these voids gain more and more importance [1]. Currently, there is no quantitative in-line metrology technique that allows voids to be identified and measured. This work aims to develop a new method to do so, by combining scatterometry (also referred to as Optical Critical Dimension or Optical CD) and low-energy x-ray fluorescence (LE-XRF), as well as machine learning techniques. By combining the inputs from these tools in the form of hybrid metrology, as well as with the incorporation of machine learning methods, we create a new metric, referred to as <i>V_xo</i>, to characterize the quantity of void. Additionally, the results are compared with inline electrical test data, as higher amounts of voids were expected to increase the measured resistivity. This was not found to be the case, as the impact of the voids was much less of a factor than variation in the cross-sectional area of the lines.

This article describes the psychometric properties of the Emotional Metric Outcomes (EMO) questionnaire and the System Usability Scale (SUS) using data collected as part of a large-sample unmoderated usability study (n = 471). The EMO is a concise multifactor standardized questionnaire that provides an assessment of transaction-driven personal and relationship emotional outcomes, both positive and negative. The SUS is a well-known standardized usability questionnaire designed to assess perceived usability. In previous research, psychometric evaluation using data from a series of online surveys showed that the EMO and its component scales had high reliability and concurrent validity with loyalty and overall experience metrics but did not find the expected four-factor structure. Previous structural analyses of the SUS have had mixed results. Analysis of the EMO data from the usability study revealed the expected four-factor structure. The factor structure of the SUS appeared to be driven by item tone. The estimated reliability of the SUS (.90) was consistent with previous estimates. The EMO and its subscales were also quite reliable, with the estimates of reliability for the various EMO scales ranging from .86 to .96. Regression analysis using SUS, EMO, and Effort as predictors revealed different key drivers for the outcome metrics of Satisfaction and Likelihood-to-Recommend. The key recommendations are to include the EMO as part of the battery of poststudy standardized questionnaires, along with the SUS (or similar questionnaire), but to be cautious in reporting SUS subscales such as Usable and Learnable.

TheCtparameter has proven very useful in correlations of creep crack growth behaviour under both transient and steady state creep conditions. In this paper, we investigate the implications of adopting a different definition of the creep zone based on an absolute measure of creep strain rather than a measure that is relative to the elastic strain. The analytical equations for small‐scale creep and transition times from small‐scale creep to extensive creep conditions are derived for theCtparameter using this alternative definition, considering both primary and secondary creep strain. It is shown that this alternative definition gives a reasonable starting point for the theory, approximately in accordance with the transient evolution of theCtparameter based on the more conventional definition of the creep zone, and removes the somewhat artificial limit of applicability imparted by the classical creep zone definition used in creep fracture mechanics. Accordingly, diffusional creep processes with a power law exponentn ≤ 3 are admitted in theCtdescription.

Most commercially available FUR instruments operate in the rapid-scan mode. In the rapid-scan mode, the moving mirror of the interferometer is scanned repeatedly at a constant velocity, thus every wavelength present is modulated at its own Fourier frequency. The sum of the sinusoids for all wavelengths in the bandwidth of the instrument is the recorded interferogram. Repeated interferograms are usually coadded before transformation in order to achieve the desired SNR. However, the rapid scan mode is difficult to apply to dynamic systems, especially when the relaxation time of the system is in the range of the commonly used Fourier modulation periods.1 This convolution of the temporal aspects of the experiment with the spectral multiplexing is avoided, and most of the advantages of (rapid-scan) FT interferometry are retained, by proper application of step-scan techniques of data acquisition. In the step-scan mode the moving mirror is stopped at, or vibrated about, each data collection point and data can be collected either in the impulse/response mode at discrete intervals of time following the impulse or in the synchronous modulation mode as in-phase and quadrature components of the signal with respect to the modulation. This modulation can be imposed either on the IR beam, or the sample&apos;s absorption, reflection or emission can be modulated by exciting the sample itself. For dynamic IR spectroscopy, the step-scan FUR mode simplifies data collection and allows relatively simple retrieval of the signal phase separate from the instrument phase. Applications illustrating how these advantages are realized in classical time-resolved spectroscopy and in phase-resolved two dimensional IR spectroscopy are illustrated below. The design principles of the step-scan interferometer used for the experiments described in this paper are covered in the paper by Manning, Palmer and Chao, in this volume (see also reference 2). In brief, the instrument is a modified IBM-IR-44; stepping is controlled by the application of a synchronous modulation to the moving mirror position and use of lock-in feedback loops to monitor the resulting modulation of the HeNe laser interference pattern. The mirror position is electronically and viscously damped. Data are collected at intervals corresponding to integral multiples of &lambda;/4HeNe; depending on the desired free spectral range, at stepping paces as slow as desired and up to 10 Hz. The design is adapted from that originally published by Debarre, Boccara and Fournier.3

Summary form only given. Signals arising from realistic collections environments may contain unwanted multipath components resulting in overlapping wavelets. Such signal components introduce extra sinusoidal transient signals into the data record, and robust spectral estimation algorithms are required. It is reported that an L/sub 1/ solution to a set of linear prediction equations provides a spectral estimate of sinusoid location with less bias and no line splitting as compared to a least-squares solution. Furthermore, computing the kurtosis of the residual vector results in an effective hypothesis test for determining whether a multipath component is present in the collected signal. Thus, the added computational expense of computing a non-least-squares solution is incurred only if required. It has been found that, in the presence of a multipath component, the L/sub 1/ solution to a set of FBLP equations provides sinusoidal frequency location with less bias and no line splitting in the test cases tried so far. >

Theory of mass removal by pulsed lasersM. SparksThe BDM Corporation 5155 West Rosecrans Avenue, Hawthorne, California 90250Growing-absorption-site theories of the coupling of pulsed- laser energy into transparent targets are based on the absorption of the laser energy by microsites in the target and on laser- induced growth of these sites. The theories provide for the first time plausible explanations of the absorption mechanism and diverse experimental results, including the cutoff of the transmitted irradiance during the pulse, three absorption depths in different experiments, rep-pulse surface temperature, plasma generation, and shock generation.

Laser-feedback noise in a GaAIAs laser was investigated as a function of optical-path length and modulation frequency.