A Statistical Approach to Improve Wafer Fabrication Yield

Author(s):  
Nael Barakat ◽  
Hesham Enshasy

In spite of the recent advancements in wafer fabrication techniques, devices are still being individually checked and modified. This is due to the fact that the general manufacturing processes involved in wafer production have their inherent inconsistencies. As a consequence, individual devices show differences in characteristics that would render a big group of them operating out of the range of the pre-set spec limits. Therefore they would require types of modifications specific to the individual device. Knowing that the resources spent on checking and eliminating out-of-spec devices before they reach the customer are very significant, the manufacturing operation becomes hardly profitable. These wafers normally carry devices in the range of a thousand or so, making a statistical approach very attractive. In this paper, an actual industrial problem in wafer fabrication to the desired specifications is presented. The problem shows in passive filters built using Surface Acoustic Wave (SAW) theory. A solution considering a statistical process control approach to the population of devices on the wafer is proposed. The results of applying this solution are realized in significant product yield increase, huge cost cutting, and automation promotion and application.

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 537
Author(s):  
Alain Gil Del Val ◽  
Fernando Veiga ◽  
Mariluz Penalva ◽  
Miguel Arizmendi

Automotive, railway and aerospace sectors require a high level of quality on the thread profiles in their manufacturing systems knowing that the tapping process is a complex manufacturing process and the last operation in a manufacturing cell. Therefore, a multivariate statistical process control chart, for each tap, is presented based on the principal components of the torque signal directly measured from spindle motor drive to diagnosis the thread profile quality. This on-line multivariate control chart has implemented an alarm to avoid defected screw threads (oversized). Therefore, it could work automatically without any operator intervention assessing the thread quality and the safety is guaranteed during the tapping process.


2021 ◽  
pp. 019459982110133
Author(s):  
Ellen S. Deutsch ◽  
Sonya Malekzadeh ◽  
Cecelia E. Schmalbach

Simulation training has taken a prominent role in otolaryngology–head and neck surgery (OTO-HNS) as a means to ensure patient safety and quality improvement (PS/QI). While it is often equated to resident training, this tool has value in lifelong learning and extends beyond the individual otolaryngologists to include simulation-based learning for teams and health systems processes. Part III of this PS/QI primer provides an overview of simulation in medicine and specific applications within the field of OTO-HNS. The impact of simulation on PS/QI will be presented in an evidence-based fashion to include the use of run and statistical process control charts to assess the impact of simulation-guided initiatives. Last, steps in developing a simulation program focused on PS/QI will be outlined with future opportunities for OTO-HNS simulation.


2013 ◽  
Vol 59 (4) ◽  
pp. 485-505 ◽  
Author(s):  
Jon E. Brommer

Abstract Individual-based studies allow quantification of phenotypic plasticity in behavioural, life-history and other labile traits. The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically significant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild populations, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that ‘scale up’ to population level processes and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10975
Author(s):  
Nicos Haralabidis ◽  
Gil Serrancolí ◽  
Steffi Colyer ◽  
Ian Bezodis ◽  
Aki Salo ◽  
...  

Biomechanical simulation and modelling approaches have the possibility to make a meaningful impact within applied sports settings, such as sprinting. However, for this to be realised, such approaches must first undergo a thorough quantitative evaluation against experimental data. We developed a musculoskeletal modelling and simulation framework for sprinting, with the objective to evaluate its ability to reproduce experimental kinematics and kinetics data for different sprinting phases. This was achieved by performing a series of data-tracking calibration (individual and simultaneous) and validation simulations, that also featured the generation of dynamically consistent simulated outputs and the determination of foot-ground contact model parameters. The simulated values from the calibration simulations were found to be in close agreement with the corresponding experimental data, particularly for the kinematics (average root mean squared differences (RMSDs) less than 1.0° and 0.2 cm for the rotational and translational kinematics, respectively) and ground reaction force (highest average percentage RMSD of 8.1%). Minimal differences in tracking performance were observed when concurrently determining the foot-ground contact model parameters from each of the individual or simultaneous calibration simulations. The validation simulation yielded results that were comparable (RMSDs less than 1.0° and 0.3 cm for the rotational and translational kinematics, respectively) to those obtained from the calibration simulations. This study demonstrated the suitability of the proposed framework for performing future predictive simulations of sprinting, and gives confidence in its use to assess the cause-effect relationships of technique modification in relation to performance. Furthermore, this is the first study to provide dynamically consistent three-dimensional muscle-driven simulations of sprinting across different phases.


2021 ◽  
Vol 33 (1) ◽  
pp. 47-70
Author(s):  
Santhoshkumar Srinivasan ◽  
Dhinesh Babu L. D.

Online social networks (OSNs) are used to connect people and propagate information around the globe. Along with information propagation, rumors also penetrate across the OSNs in a massive order. Controlling the rumor propagation is utmost important to reduce the damage it causes to society. Educating the individual participants of OSNs is one of the effective ways to control the rumor faster. To educate people in OSNs, this paper proposes a defensive rumor control approach that spreads anti-rumors by the inspiration from the immunization strategies of social insects. In this approach, a new information propagation model is defined to study the defensive nature of true information against rumors. Then, an anti-rumor propagation method with a set of influential spreaders is employed to defend against the rumor. The proposed approach is compared with the existing rumor containment approaches and the results indicate that the proposed approach works well in controlling the rumors.


Author(s):  
Lee J. Wells ◽  
Jaime A. Camelio ◽  
Giovannina Zapata

Statistical process monitoring and control has been popularized throughout the manufacturing industry as well as various other industries interested in improving product quality and reducing costs. Advances in this field have focused primarily on more efficient ways for diagnosing faults, reducing variation, developing robust design techniques, and increasing sensor capabilities. System level advances are largely dependent on the introduction of new techniques in the listed areas. A unique system level quality control approach is introduced in this paper as a means to integrate rapidly advancing computing technology and analysis methods in manufacturing systems. Inspired by biological systems, the developed framework utilizes immunological principles as a means of developing self-healing algorithms and techniques for manufacturing assembly systems. The principles and techniques attained through this bio-mimicking approach will be used for autonomous monitoring, detection, diagnosis, prognosis, and control of station and system level faults, contrary to traditional systems that largely rely on final product measurements and expert analysis to eliminate process faults.


Author(s):  
Neelakantan Mani ◽  
Jami J. Shah ◽  
Joseph K. Davidson

The choice of fitting algorithm in CMM metrology has often been based on mathematical convenience rather than the fundamental GD&T principles dictated by the ASME Y14.5 standard. Algorithms based on the least squares technique are mostly used for GD&T inspection and this wrong choice of fitting algorithm results in errors that are often overlooked and leads to deficiency in the inspection process. The efforts by organizations such as NIST and NPL and many other researchers to evaluate commercial CMM software were concerned with the mathematical correctness of the algorithms and developing efficient and intelligent methods to overcome the inherent difficulties associated with the mathematics of these algorithms. None of these works evaluate the ramifications of the choice of a particular fitting algorithm for a particular tolerance type. To illustrate the errors that can arise out of a wrong choice of fitting algorithm, a case study was done on a simple prismatic part with intentional variations and the algorithms that were employed in the software were reverse engineered. Based on the results of the experiments, a standardization of fitting algorithms is proposed in light of the definition provided in the standard and an interpretation of manual inspection methods. The standardized fitting algorithms developed for substitute feature fitting are then used to develop Inspection maps (i-Maps) for size, orientation and form tolerances that apply to planar feature types. A methodology for Statistical Process Control (SPC) using these i-Maps is developed by fitting the i-Maps for a batch of parts into the parent Tolerance Maps (T-Maps). Different methods of computing the i-Maps for a batch are explored such as the mean, standard deviations, computing the convex hull and doing a principal component analysis of the distribution of the individual parts. The control limits for the process and the SPC and process capability metrics are computed from inspection samples and the resulting i-Maps. Thus, a framework for statistical control of the manufacturing process is developed.


2011 ◽  
Vol 4 (1/2) ◽  
pp. 37 ◽  
Author(s):  
Katerina Dimaki ◽  
Vasilis Angelis ◽  
Stelios Psarakis ◽  
Ilias Virras ◽  
Vasilis A. Angelis

Lituanistica ◽  
2020 ◽  
Vol 66 (3) ◽  
Author(s):  
Olga Mastianica-Stankevič

The magazine Aušrinė was intended for the young generation of the Lithuanian intelligentsia and as it was created by the representatives of this generation it allowed understanding of the collective thinking of this group of society. In the first half of the twentieth century, the young generation of the Lithuanian intelligentsia defined the intelligentsia not so much by formal characteristics as by its cultural, and, more precisely, by its national role. The collaborators of Aušrinė were convinced that the future of the Lithuanian national movement and the Lithuanian nation depended on the intelligentsia and its role. However, unlike other periodicals of the time, the editors of this magazine mostly focused not on the dissemination of ideas of Lithuanian nationalism, but looked for ways to strengthen social activism of the intellectuals, their relations with the homeland and with other sections of society. It was the environment of Aušrinė that tied student summer holidays to learning about regions, history, and culture of Lithuania, encouraged students to actively participate in the activities of farming societies, enlightenment societies, and to bring together local youth societies. In parallel, this magazine addressed the issue of the harmonisation of the individual needs of the intelligentsia and the community needs. Among other things, the collaborators of Aušrinė claimed that the Lithuanian intellectuals would not be able to properly perform their social functions unless they cared more about the nurturing of individuality: moral self-development and intellectual education. By introducing the column “Educational Affairs”, the editors of this magazine provided a list of literature recommended to the students, knowing that it would help the young generation of the Lithuanian intelligentsia “to seriously, consciously, and consistently develop a worldview, to accurately determine the path of an active life”. The discussion in the magazine Aušrinė shows that in the vision of the nation’s future, the young generation of the Lithuanian intelligentsia encouraged regarding women not only as wives and mothers in order to implement projects of the national intelligent family, but as partners in social activities. The editors of the magazine emphasized the need for women’s participation in the process of building a national intelligentsia and encouraged them to be socially active.


Sign in / Sign up

Export Citation Format

Share Document