Тестирование скрытых дефектов в соединениях

Electronic instrumentation has a constant growth density layout and functionality. This entails an increase in the density of interconnection elements by increasing their number and reducing the size of it. The growing cost of interconnection structures (printed circuit boards, printing and wired mounting) associated with their complexity and increase of their reliability requirements, result in the search of new and improved non-destructive diagnostic methods and means of control. However, the existing methods do not allow control interconnects with sufficient certainty to identify a significant number of hidden defects. This class of defects can be diagnosed by means of non-destructive testing of interconnections, based on the detection of controlled circuit reaction to a current. The paper describes the principles for calculating the current to exercise that control.Электронное приборостроение находится в состоянии постоянного роста плотности компоновки и функциональности. Это влечет за собой рост плотности элементов межсоединений за счет увеличения их количества и уменьшения размеров. Возрастание стоимости конструкций межсоединений (печатных плат, печатного и проводного монтажа), связанное с их усложнением и возрастанием требований к надежности, обуславливает поиск новых и совершенствование существующих неразрушающих диагностических методов и средств контроля. Однако, существующие методы контроля межсоединений не позволяют с достаточной достоверностью выявить значительную часть скрытых дефектов. Такие дефекты могут быть диагностированы при помощи неразрушающего контроля соединений, основанного на регистрации реакции контролируемых цепей на воздействие импульса тока. В статье описываются принципы расчета параметров импульса тока и способ реализации такого контроля

Эпоксидно-стеклянные композиционные материалы для подложек печатных плат гигабитной электроники

The development of printed circuit board technology is a subject to the general trend of electronics development, an increase in functionality and performance. This requires printed circuit boards to increase the assembly density of electronic components and interconnections and reduction of constructive delays in transmission lines of information. Seemingly, this will require the use of high frequency materials such as polytetrafluorethylenes (PTPE) or radiofrequency ceramics. However, this would require a multi-billion dollar restructuring of the industry of printed circuit boards. The article shows that under certain conditions it is possible to do without the restructuring of the industry, remaining on traditional foil epoxy-glass composite dielectrics. But for this purpose, it is necessary to take into account their characteristics and properties of their components.El desarrollo de la tecnología de placa de circuito impreso sigue la tendencia general del desarrollo de la electrónica: se busca producir un aumento tanto en la funcionalidad como en el rendimiento. Esto requiere placas de circuito impreso para aumentar la densidad de ensamblaje de componentes electrónicos e interconexiones y reducir los retrasos constructivos en las líneas de transmisión de información. Aparentemente, esto requeriría el uso de materiales de alta frecuencia como tereftalato de polietileno o cerámica de radiofrecuencia. Sin embargo, ello conllevaría una reestructuración multimillonaria de la industria de placas de circuito impreso. El presente artículo muestra que, cumpliéndose ciertas condiciones, es posible prescindir de la reestructuración de la industria, permaneciendo el uso de dieléctricos compuestos de lámina de vidrio epoxi tradicionales. Sin embargo, para lograr este propósito es necesario tener en cuenta las características y propiedades de sus componentes.Развитие технологии печатных плат зависит от общей тенденции развития электроники - увеличения функциональности и производительности. Это требует от печатных плат увеличение плотности компоновки электронных компонентов и соответствующего увеличения плотности межсоединений и их длины для уменьшения конструктивных задержек в линиях передачи информации. По-видимому, это потребует использования высокочастотных материалов, таких как политетрафторэтилен или радиочастотная керамика. Однако это потребует многомиллиардной реструктуризации индустрии печатных плат. В статье показано, что при определенных условиях можно обойтись без перестройки отрасли, оставаясь на традиционных фольгированных стекло-эпоксидных композитных диэлектриках. Но для этого необходимо учитывать их характеристики и свойства составляющих

Analytical Model for Evaluating the Reliability of Vias and Plated Through-Hole Pads on PCBs

Currently, there is a need to increase the density of interconnections on printed circuit boards (PCBs). Does this mean that the only option for quality PCB manufacturing is to proportionally increase precision of equipment, or is there another way? One of the main constraints on increasing the density of PCB interconnections is posed by the transition holes. As the number of conductive layers increases, the number of vias increases and they cover a significant space on the PCB. On the other hand, reducing the size of the vias is limited by the capability of spatial alignment of the PCB stack during manufacturing. There are standards that set limits for the design of contact pads on a PCB (IPC-A-600G, IPC-6012B). However, depending on the precision of production, the contact pads may be of poor quality. This raises the issue of determining the reliability of a contact pad with defined parameters at the design stage, taking into account manufacturing capabilities. This research proposes an analytical method for evaluation of reliability of a via or plated through-hole based on calculation of its probability of production in accordance with the current standards. On the basis of the method, a model was developed both for the case of a contact pad without any conductors connected to it (nonfunctional contact pad) and for the real case with a connected conductor. The model estimates the probability of making an acceptable via for a given reliability class depending on parameters such as the conductor width (minimum permissible and usable), drilled hole diameter, and pad diameter, as well as the accuracy of the drilling operation. The analysis of the modeling results showed that for the real case, a reduction in the reliability class would insignificantly affect the probability of making an acceptable via due to the tight limitation on the connection place of the conductor and the contact pad. In conclusion, we propose an algorithm for determining the optimal parameters of teardrops to minimize the negative impact of the conductor on the reliability of the vias

Development of the Digital Site for Chemical Processes in the Manufacturing of Printed Circuit Boards

The article defines digital methods for controlling the quality of chemical processes. An architecture of a digital production line, which ensures the distribution of the computational load between the system components, is proposed. We considered the process of developing a prototype of a digital production site for servicing the etching operation during which controllable process parameters are determined; both hardware and software structures of the digital site are proposed. Studying the site operability, we determined the relationships between the process parameters, which made it possible to determine the boundaries of the designed system

Engineering and Analytical Method for Estimating the Parametric Reliability of Products by a Low Number of Tests

The paper provides an overview of methods for determining reliability indicators and, on the basis of the analysis, proposes a new method for assessing the parametric reliability of products based on a small number of tests. The determination of the parameters and double logistic distribution based on the test results is considered, a statistical experiment was carried out, which was based on the method of statistical modeling of Monte Carlo. An example of evaluating parametric reliability by a new method is also given, on the basis of which an engineering technique is proposed. In the conclusion, remarks are made regarding the advantages of the novel method

Engineering and Analytical Method for Estimating the Parametric Reliability of Products by a Low Number of Tests

The paper provides an overview of methods for determining reliability indicators and, on the basis of the analysis, proposes a new method for assessing the parametric reliability of products based on a small number of tests. The determination of the parameters and double logistic distribution based on the test results is considered, a statistical experiment was carried out, which was based on the method of statistical modeling of Monte Carlo. An example of evaluating parametric reliability by a new method is also given, on the basis of which an engineering technique is proposed. In the conclusion, remarks are made regarding the advantages of the novel method

Influence of Substituents in a Six-Membered Chelate Ring of HG-Type Complexes Containing an N→Ru Bond on Their Stability and Catalytic Activity

An efficient approach to the synthesis of olefin metathesis HG-type catalysts containing an N→Ru bond in a six-membered chelate ring was proposed. For the most part, these ruthenium chelates can be prepared easily and in high yields based on the interaction between 2-vinylbenzylamines and Ind II (the common precursor for Ru-complex synthesis). It was demonstrated that the increase of the steric volume of substituents attached to the nitrogen atom and in the α-position of the benzylidene fragment leads to a dramatic decrease in the stability of the target ruthenium complexes. The bulkiest iPr substituent bonded to the nitrogen atom or to the α-position does not allow the closing of the chelate cycle. N,N-Diethyl-1-(2-vinylphenyl)propan-1-amine is a limiting case; its interaction with Ind II makes it possible to isolate the corresponding ruthenium chelate in a low yield (5%). Catalytic activity of the synthesized complexes was tested in RCM reactions and compared with α-unsubstituted catalysts obtained previously. The structural peculiarities of the final ruthenium complexes were thoroughly investigated using XRD and NMR analysis, which allowed making a reliable correlation between the structure of the complexes and their catalytic properties