Electronics Manufacturing Technical Articles

Factors Affecting the Adhesion of Thin Film Copper on Polyimide

Nov 22, 2017 | David Ciufo, Hsin-Yi Tsai and Michael J. Carmody

The use of copper foils laminated to polyimide (PI) as flexible printed circuit board precursor is a standard practice in the PCB industry. We have previously described[1] an approach to very thin copper laminates of coating uniform layers of nano copper inks and converting them into conductive foils via photonic sintering with a multibulb conveyor system, which is consistent with roll-to-roll manufacturing. The copper thickness of these foils can be augmented by electroplating. Very thin copper layers enable etching fine lines in the flexible circuit. These films must adhere tenaciously to the polyimide substrate.

In this paper, we investigate the factors which improve and inhibit adhesion. It was found that the ink composition, photonic sintering conditions, substrate pretreatment, and the inclusion of layers (metal and organic) intermediate between the copper and the polyimide are important....

Publisher: Intrinsiq Materials Inc.

Controlling Voiding Mechanisms in the Reflow Soldering Process

Nov 15, 2017 | Keith Sweatman, Takatoshi Nishimura, Kenichiro Sugimoto, Akira Kita

While a significant level of voiding can be tolerated in solder joints where electrical conductivity is the main requirement, voiding at any level severely compromises thermal conductivity. For example, in LED lighting modules effective conduction of heat through the 1st level die attach to the substrate and then through the 2nd level attach to the heat sink is critical to performance so that voiding in the solder joints at both levels must be minimized. (...) In this paper, the authors will review the factors that influence the incidence of voids in small and large area solder joints that simulate, respectively, the 1st and 2nd level joints in LED modules and discuss mitigation strategies appropriate to each level. They will also report the results of a study on the effect on the incidence of voids of flux medium formulation and the optimization of the thermal profile to ensure that most of the volatiles are released early in the reflow process....

Publisher: Nihon Superior Co., Ltd.

Why Design PCB Assemblies with Testing in Mind?

Nov 14, 2017 | Tuan Tran

Can you put a product that hasn't been fully tested on the market? When it comes to Printed Circuit Board (PCB) assembly and manufacturing, most firms’ answer is neither a strict yes or no. ...

Publisher: Power Design Services

Soldering fume in electronics manufacturing - damaging effects and solutions for removal

Nov 10, 2017 | ULT AG

Modern electronics manufacturing is made up by a multiplicity of different separation and joining processes, with the later surely taking the vast majority of production technology. Alongside gluing, welding and laser processes, soldering still holds a primary position in electronic assemblies. However, soldering does not always equal soldering, because there are quite a lot of different soldering technologies. Accordingly, you have to distinguish between automated and manual soldering procedures. No matter which soldering process you analyse, all of them have one aspect in common: they produce airborne pollutants, which may have a negative impact on employees, plants and products as well....

Publisher: ULT Canada Sales Incorporated

Void Reduction in Reflow Soldering Processes by Sweep Stimulation of PCB Substrate

Nov 08, 2017 | Viktoria Rawinski

Due to the ongoing trend towards miniaturization of power components, the need for increased thermal conductivity of solder joints in SMT processes gains more and more importance. Therefore, the role of void free solder joints in power electronics becomes more central. Voids developed during soldering reduce the actual thermal transfer and can cause thermal damage of the power components up to their failure. For this reason, the company has developed a new technique to minimize the formation of these voids during the soldering process....

Publisher: kurtz ersa Corporation

Solder Paste Printing – the Most Critical Part of Building a Quality PCB Explained

Nov 03, 2017 | Tuan Tran

If someone were to ask what the most important part of their favorite electronic device is, they are likely to point to the printed circuit board (PCB) responsible for making the device work before moving on to other components. From large motherboards to tiny chips, most of the technology that retail consumers take for granted comes down to a properly installed and calibrated PCB. ...

Publisher: Power Design Services

Just‐In‐Time Material Management for the PCB Industry

Nov 03, 2017 | Tuan Tran

As with any production industry, businesses in the PCB industry need to maintain a healthy balance between the components they keep in stock and those they use for meet client orders. Ordering too many components comes with serious disadvantages, as does not ordering enough, and PCB manufacturers need to stay as close as possible to a happy medium between the two....

Publisher: Power Design Services

21st Century PCB FAB Factory Design Which Eliminates Regional Cost Advantages

Nov 01, 2017 | Alexander Stepinski

Over fifteen years has passed since North America and Europe ceased being the center of worldwide PCB fabrication, and were supplanted by a Far East market with low cost labor, more relaxed environmental requirements, and strong government support. In just a few short years, the superior cost advantages of this new dynamic put volume PCB production in the West out of business, aside for the military and specialty technology applications contained in the few shops that continue to exist today.

Recently, however, the conditions which created the current equilibrium appear to be shifting again. In this new dynamic, automation, innovative green wastewater technologies, and next generation process equipment innovations have combined to make new factories capable of achieving rapid ROI for PCB fabrication almost anywhere. This paper means to illustrate this new dynamic, and provide case study examples from the new greenfield installation at the company captive facility in New Hampshire....

Publisher: Whelen Engineering

Can Nano-Coatings Really Improve Stencil Performance?

Oct 26, 2017 | Tony Lentz

Nano-coatings have been introduced by various manufacturers, with the promise of addressing some of the challenges relative to solder paste printing. Stated benefits include: Reduced underside cleaning, reduced bridging, improved solder paste release and improvements in yield. With several nano technologies already on the market and more likely to be introduced, how can the performance be quantified? How robust are these coatings? How can an assembler approach the ROI of these coatings? What hidden benefits or negative impacts should be considered?

This paper will present a rigorous method for evaluating the performance and economic benefits of solder paste stencil nano-coatings....

Publisher: FCT ASSEMBLY, INC.

To Quantify a Wetting Balance Curve

Oct 19, 2017 | Frank Xu Ph.D., Robert Farrell, Rita Mohanty Ph.D.

Wetting balance testing has been an industry standard for evaluating the solderability of surface finishes on printed circuit boards (PCB) for many years. A Wetting Balance Curve showing Force as a function of Time, along with the individual data outputs "Time to Zero" T(0), "Time to Two-Thirds Maximum Force" T(2/3), and "Maximum Force" F(max) are usually used to evaluate the solderability performance of various surface finishes. While a visual interpretation of the full curve is a quick way to compare various test results, this method is subjective and does not lend itself readily to a rigorous statistical evaluation. Therefore, very often, when a statistical evaluation is desired for comparing the solderability between different surface finishes or different test conditions, one of the individual parameters is chosen for convenience. However, focusing on a single output usually doesn't provide a complete picture of the solderability of the surface finish being evaluated.

In this paper, various models here-in labeled as "point" and "area" models are generated using the three most commonly evaluated individual outputs T(0), T(2/3), and F(max). These models have been studied to quantify how well each describes the full wetting balance curve. The solderability score (S-Score) with ranking from 0 to 10 were given to quantify the wetting balance curve as the result of the model study, which corresponds well with experimental results....

Publisher: Enthone