Technical Library | 2021-01-28 01:55:00.0
Printed circuit board surface finishes are a topic of constant discussion as environmental influences, such as the Restriction of Hazardous Substances (RoHS) Directive or technology challenges, such as flip chip and 01005 passive components, initiate technology changes. These factors drive the need for greater control of processing characteristics like coplanarity and solderability, which influence the selection of surface finishes and impact costs as well as process robustness and integrity. The ideal printed circuit board finish would have good solderability, long shelf life, ease of fabrication/processing, robust environmental performance and provide dual soldering/wirebonding capabilities; unfortunately no single industry surface finish possesses all of these traits. The selection of a printed circuit board surface finish is ultimately a series of compromises for a given application.
Technical Library | 2016-06-16 15:29:31.0
Embedding components within the PC board structure is not a new concept. Until recently, however, most embedded component PC board applications adapted only passive elements. The early component forming processes relied on resistive inks and films to enable embedding of resistor and capacitors elements. Although these forming methods remain viable, many companies are choosing to place very thin discrete passive components and semiconductor die elements within the PC board layering structure. In addition to improving the products performance, companies have found that by reducing the component population on the PC board's surface, board level assembly is less complex and the PC board can be made smaller, The smaller substrate, even when more complex, often results in lower cost. Although size and cost reductions are significant attributes, the closer coupling of key elements can also contribute to improving functional performance.This paper focuses on six basic embedded component structure designs described in IPC-7092.
Technical Library | 2013-12-05 17:09:03.0
The functionality of electronic devices continues to increase at an extraordinary rate. Simultaneously consumers are expecting even more and in ever smaller packages. One enabler for shrinking electronics has been the flexible circuit board that allows the circuit board to fit a wide variety of shapes. Flexible printed circuits (FPC) have the capability to be very thin and can have unpackaged components directly attached using surface mount technology (SMT) and flip chip on flex technologies. Bare die can also be thinned and attached very close to the circuit board. However one caveat of high density flexible circuit boards with thin die is that they can be very fragile. The use of back side films and underfill can protect the die making circuits more robust. For underfill to work well it requires good adhesion to the circuit board which can mean that flux residues under the die normally must be removed prior to underfilling.
Technical Library | 1999-05-06 14:48:20.0
This paper describes manufacturing operations design and analysis at Intel. The complexities and forces of both the market and the manufacturing process combine to make the development of improved semiconductor fabrication manufacturing strategies (like lot dispatching, micro and macro scheduling policies, labor utilization, layout, etc.) particularly important...
Technical Library | 2021-12-21 23:15:44.0
High Density Interconnect (HDI) technologies are being used widely in Asia and Europe in consumer electronics for portable wireless communication and computing, digital imaging, and chip packaging. Although North America lags behind in developing process capability for this technology, HDI will become a significant business segment for North America. For this to happen, the printed circuit board shops will have to become process capable in fabricating fine lines and spaces, and also be capable in forming and plating microvias.
Technical Library | 2018-07-03 12:27:02.0
It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach
Technical Library | 2016-09-15 17:10:40.0
This paper describes the purpose, methodology, and results to date of thermal endurance testing performed at the company. The intent of this thermal aging testing is to establish long term reliability data for printed wiring board (PWB) materials for use in applications that require 20+ years (100,000+ hours) of operational life under different thermal conditions. Underwriters Laboratory (UL) testing only addresses unclad laminate (resin and glass) and not a fabricated PWB that undergoes many processing steps, includes copper and plated through holes, and has a complex mechanical structure. UL testing is based on a 5000 hour expected operation life of the electronic product. Therefore, there is a need to determine the dielectric breakdown / degradation of the composite printed circuit board material and mechanical structure over time and temperature for mission critical applications.
Technical Library | 2019-05-01 23:18:27.0
Moisture can accelerate various failure mechanisms in printed circuit board assemblies. Moisture can be initially present in the epoxy glass prepreg, absorbed during the wet processes in printed circuit board manufacturing, or diffuse into the printed circuit board during storage. Moisture can reside in the resin, resin/glass interfaces, and micro-cracks or voids due to defects. Higher reflow temperatures associated with lead-free processing increase the vapor pressure, which can lead to higher amounts of moisture uptake compared to eutectic tin-lead reflow processes. In addition to cohesive or adhesive failures within the printed circuit board that lead to cracking and delamination, moisture can also lead to the creation of low impedance paths due to metal migration, interfacial degradation resulting in conductive filament formation, and changes in dimensional stability. Studies have shown that moisture can also reduce the glass-transition temperature and increase the dielectric constant, leading to a reduction in circuit switching speeds and an increase in propagation delay times. This paper provides an overview of printed circuit board fabrication, followed by a brief discussion of moisture diffusion processes, governing models, and dependent variables. We then present guidelines for printed circuit board handling and storage during various stages of production and fabrication so as to mitigate moisture-induced failures.
Technical Library | 2021-02-17 22:13:39.0
The development of various biosensors has revolutionized the healthcare industry by providing rapid and reliable detection capability. Printed circuit board (PCB) technology has a well-established industry widely available around the world. In addition to electronics, this technology has been utilized to fabricate electrical parts, including electrodes for different biological and chemical sensors. High reproducibility achieved through long-lasting standard processes and low-cost resulting from an abundance of competitive manufacturing services makes this fabrication method a prime candidate for patterning electrodes and electrical parts of biosensors. The adoption of this approach in the fabrication of sensing platforms facilitates the integration of electronics and microfluidics with biosensors. In this review paper, the underlying principles and advances of printed board circuit technology are discussed. In addition, an overview of recent advancements in the development of PCB-based biosensors is provided. Finally, the challenges and outlook of PCB-based sensors are elaborated. doi:10.3390/bios10110159
Technical Library | 1999-05-06 13:38:45.0
This paper traces the key steps that led to the invention of the integrated circuit (IC). The first part of this paper reviews the steady improvements in the performance and fabrication of single transistors in the decade after the Bell Labs breakthrough work in 1947. It sketches the various developments needed to produce a practical IC. In addition, the more advanced processes such as diffusion, oxide masking, photolithography, and epitaxy, which culminated in the planar process, are summarized.
