The 43rd Annual Symposium of the European Circuit Technology Research Institute was held in the Black area in central England in May. The theme of this workshop is design and its impact on PCB manufacturability and reliability.
Dr. Andy Cobley, President of ICT, warmly welcomed the PCB professionals attending the meeting. They are very much appreciate the session of the seminar, but also very happy to be together to communicate with their peers.
Martin Cotton, director of OEM technology at Ventec, tells of his career and life for the past 50 years. He also talked about his current mission is to use their knowledge and experience to guide OEM customers to select their substrate materials, while optimizing product performance and functionality while also having the best manufacturability and cost-effectiveness.
Speaking of today's design challenges, Cotton focuses on a new generation of high-speed materials and explores how it can help designers avoid over-narrowing of controlled impedance lines as well as how to mitigate the " Resistance and the indirect effect of the insertion loss.
Michael Ford, senior market development manager at Mentor Graphics, analyzes the important roles that DFM plays in the introduction of new products, through the problems that arise during the transition from "Industrial 3.0" to "Industrial 4.0" Point to the topic, including process automation, the computerization of human decision-making and optimization based on the prevailing environmental conditions, as well as the importance of these issues in the lean context.
Ford explains that traditional electronic product ecosystems are a cycle of market analysis and finally market analysis: creating opportunities, designing products, PCB design layouts, PCB manufacturing, acquisition components, assembly, testing, transportation and distribution. The highest cost stage in the value chain is the distribution phase; compared to the cost of assembly is relatively insignificant. For example, if you make a smartphone in Germany, then the cost of manufacturing will be higher but the cost of distribution will be lower. But PCB design is the most critical step in this cycle, because it will have an impact on each subsequent step, and will eventually lead to missed market opportunities, lost confidence in the product. While a simple design rule check can detect places that do not meet the requirements, it will also ignore a lot of problems that will become apparent in later processes (production, testing, or worst case - failure after putting into the market). Therefore, it is critical to use more intelligent design analysis tools to support NPI processes.
The rapid development of PCB interconnect technology is not common, from NextGIn Technology's Joan Tourné about their views on VeCS. VeCS is an effective alternative to Z-axis interconnects, attracting a large number of OEM designers. He explains that the main limitation of current HDI technology is the density of vertical interconnections, which need to be processed multiple times by sequential lamination (very expensive solutions). "Why do you have to keep things smaller - why do not you make things easier?" In the VeCS method, the metalized holes are replaced by vertical or semi-cylinders, making the vertical connections within the unit area More, can also be more wiring area. Further, it is also possible to connect the vertical conductor to the plurality of inner layers as required. In addition, the method can also enhance signal integrity and eliminate CAF paths.
In the case of the same interconnection density, reducing the number of layers can save costs. If necessary, VeCS can be partially integrated into other conventional layouts to solve a variety of problems, such as fan-out problems under micro-spacing array packaging. One of the advantages of VeCS is that it can reduce the interference of the inner layer and enhance the signal integrity.
Market analyst Francesca Stern explained the global PCB industry and electronics industry profile, so far in 2017 the British PCB production showed moderate growth, but she believes that now is the peak of growth, its value will appear in the second half of this year and 2018 Down. Britain's PCB market growth is slow, to 2018 will remain stable, no longer grow, but it is still a net importer. Her statistical results do not calculate the cost of materials due to exchange rate fluctuations and supply chain problems. She predicts that PCB production in Europe will peak in 2017, followed by a slight negative growth in 2018; PCB production in the United States will not increase in 2017, but we hope to see some growth trends in 2018. If the statistical results of flexible products and rigid products, China, including Taiwan, the growth trend is very good, but a large number of growth is actually appear in the flexible products. In addition, she predicted that the recent PCB production in Japan will not grow.
Back to the design theme, especially in high-speed design, Signal Integrity, Polar Instruments Signal Integrity Product Manager Neil Chamberlain tells the actual effect of copper surface roughness on the insertion loss and how it is quantified as a transmission line field solution Mathematical parameters.
He explained that although the DC current will flow evenly across the conductor cross-section, but 10 MHz and above the frequency of alternating current mainly through the outer layer of the conductor. As the conductor becomes smaller and smaller, the skin effect becomes more and more serious, more and more easily occur at lower frequencies. "What is the correlation between frequency and impedance? There is virtually no association! But at high frequencies, dielectric loss is a big problem."
The copper foil used in the PCB production is intentionally roughened by electrolytic or chemical means, through which the adhesion of the copper foil to the laminated resin is enhanced. Although the "thin" and "ultra-thin" copper foil has been listed, but they still have a certain surface roughness, which has a serious impact on the skin effect, which also has a serious impact on the loss of the plug.
PCB designers and pre-production engineers use field-solving tools to accurately model the frequency-related PCB transmission lines, which helps to select the appropriate design rules and material parameters. "All the models are wrong, but some of them are useful." This sentence is widely circulated in the field of high-speed design. Chamberlain emphasizes that effective modeling depends on whether the input data is meaningful, so the method used to calculate the loss of the insertion must incorporate the surface roughness into the consideration. But how does this measure and specify a value?
The previously used method is based on the mechanical measurement of the equivalent number and the depth of the conductor surface, but these methods are now limited in their role and are only effective at low frequencies. Huray's approach is to show the shape of the conductor surface in a pyramid form of snowballs and to calculate the energy consumption of the skin depth and the number and distribution of snowballs per unit area. The method uses a different snowball radius to simulate and uses a single effective sphere radius to simplify the formula in practical applications.
Dennis Price interprets the manufacturability design from the perspective of a PCB manufacturer, listing a number of issues that Michael Ford raised in his previous speech.
He explores the relative costs and yield factors associated with a range of HDI structures, the type of laminate specified, and whether it is the best choice for performance, reliability, availability and cost-effectiveness. He also introduced the decisions made in determining the multilayer stacks for impedance control designs and the importance of making meaningful drawings. So much information - this does not include the PCB layout data test! He explained that the PCB designer would run a DFM test to determine its manufacturability before giving the design to the PCB manufacturer, regardless of which software tools to use, and to remove any design before leaving the design Conform to the normative or ambiguous place.
Which designs lead to manufacturability problems and potential reductions in production? Price shows a number of examples: components and planes are elongated, uneven copper distribution, uniformity of coating, flatness and dimensional stability of the impact of poor positioning holes, through-hole pad problem, the pad Of the components of the logo, automatic wiring errors and no terminal wiring, copper and cross problems, do not meet the same net spacing and other issues. The vast majority of the problems can be found and corrected at the design stage using the DF600 tool introduced by Michael Ford.
Bill Wilkie came to power again for this delightful and informative annual seminar, and he thanked the conference sponsor Ventec for his invitation and invited Martin Cotton to come to an end. Cotton gave a philosophical example, and he thought that Einstein's theory of "knowledge circle" was equally applicable to the design and manufacture of printed circuits in reality. In the circle is known, outside the circle is unknown, and the interface between the two is the human curiosity. The larger the circle, the greater the interface between known and unknown. The more knowledge you know, the more unknown the knowledge will increase, the more you get the answer, the more questions you need to ask. In the words of Cotton, "ignorance is a blessing: if a person does not know anything, then he has nothing to learn!"
Source: I-Connect007
