Technical Library | 2020-06-19 19:08:14.0
The designs of electronic devices and systems are being continuously improved by becoming smaller in size and faster in communication speed. The potential risk associated with these specific design improvements will be an increase in power density and, consequently, a greater risk of thermal problems and failures. At the same time, the prevailing use of circuit boards integrated with power devices such as motor controllers and drivers, light-emitting diode (LED) lighting modules, power supplies, and amplifiers, and regulators for TV, etc., drive to the use of a proper thermal management system while designing these kinds of printed circuit board (PCB).
Technical Library | 2022-09-25 20:18:33.0
Printed circuit board (PCB) bending and/or flexing is an unavoidable phenomenon that is known to exist and is easily encountered during electronic board assembly processes. PCB bending and/or flexing is the fundamental source of tensile stress induced on the electronic components on the board assembly. For more brittle components, like ceramic-based electronic components, micro-cracks can be induced, which can eventually lead to a fatal failure of the components. For this reason, many standards organizations throughout the world specify the methods under which electronic board assemblies must be tested to ensure their robustness, sometimes as a pre-condition to more rigorous environmental tests such as thermal cycling or thermal shock.
Technical Library | 2010-05-06 18:46:29.0
Stencil printing technology has come a long way since the early 80’s when SMT process gained importance in the electronics packaging industry. In those early days, components were fairly large, making the board design and printing process relatively simple. The current trend in product miniaturization has led to smaller and more complex board designs. This has resulted into designs with maximum area utilization of the board space. It is not uncommon, especially for hand held devices, to find components only a few millimeters from the edge of the board. The board clamping systems used in the printing process have become a significant area of concern based on the current board design trend.
Technical Library | 2016-05-12 16:29:40.0
Advances in miniaturized electronic devices have led to the evolution of microvias in high density interconnect (HDI) circuit boards from single-level to stacked structures that intersect multiple HDI layers. Stacked microvias are usually filled with electroplated copper. Challenges for fabricating reliable microvias include creating strong interface between the base of the microvia and the target pad, and generating no voids in the electrodeposited copper structures. Interface delamination is the most common microvia failure due to inferior quality of electroless copper, while microvia fatigue life can be reduced by over 90% as a result of large voids, according to the authors’ finite element analysis and fatigue life prediction. This paper addresses the influence of voids on reliability of microvias, as well as the interface delamination issue.
Technical Library | 2020-07-15 18:29:34.0
In the early 2000s the first fine-pitch ball grid array devices became popular with designers looking to pack as much horsepower into as small a space as possible. "Smaller is better" became the rule and with that the mechanical drilling world became severely impacted by available drill bit sizes, aspect ratios, and plating methodologies. First of all, the diameter of the drill needed to be in the 0.006" or smaller range due to the reduction of pad size and spacing pitch. Secondly, the aspect ratio (depth to diameter) became limited by drill flute length, positional accuracy, rigidity of the tools (to prevent breakage), and the throwing power of acid copper plating systems. And lastly, the plating needed to close up the hole as much as possible, which led to problems with voiding, incomplete fill, and gas/solution entrapment.
Technical Library | 2015-07-16 17:24:23.0
Qualification of electronic hardware from a corrosion resistance standpoint has traditionally relied on stressing the hardware in a variety of environments. Before the development of tests based on mixed flowing gas (MFG), hardware was typically exposed to temperature-humidity cycling. In the pre-1980s era, component feature sizes were relatively large. Corrosion, while it did occur, did not in general degrade reliability. There were rare instances of the data center environments releasing corrosive gases and corroding hardware. One that got a lot of publicity was the corrosion by sulfur-bearing gases given off by data center carpeting. More often, corrosion was due to corrosive flux residues left on as-manufactured printed circuit boards (PCBs) that led to ion migration induced electrical shorting. Ion migration induced failures also occurred inside the PCBs due to poor laminate quality and moisture trapped in the laminate layers.
Technical Library | 2015-08-18 18:39:13.0
Jetting Valve Technology Superior to Needle Dispensing Compared to traditional needle dispensing technology, jetting valve technology is the most effective method for quick and accurate fluid dispensing. Injection technology has many advantages, it provides a combination of high-speed, high quality and low cost production for fluid dispensing processes. Instead of putting focus on getting the application done, jet dispense technology focuses on performance, providing applications like underfill, potting and encapsulation with more precision than ever before. Improved Fluid Dispensing Speed and Accuracy Non-contact jetting valves offer a significant advantage over traditional needle dispense valves. Jetting Valve Dispenser precision reaches to 200µm with dot diameter or line width as small as 250µm and volumetric dispensing down to .0036µl. Minimum space between lines is 180µm and maximum fluid dispense speed is 200 dots/second. The following video illustrates quick, accurate fluid dispensing for an LED packaging application.
Technical Library | 2019-07-17 17:56:34.0
The increased demand for electronic devices in recent years has led to an extensive research in the field to meet the requirements of the industry. Electrolytic copper has been an important technology in the fabrication of PCBs and semiconductors. Aqueous sulfuric acid baths are explored for filling or building up with copper structures like blind micro vias (BMV), trenches, through holes (TH), and pillar bumps. As circuit miniaturization continues, developing a process that simultaneously fills vias and plates TH with various sizes and aspect ratios, while minimizing the surface copper thickness is critical. Filling BMV and plating TH at the same time, presents great difficulties for the PCB manufactures. The conventional copper plating processes that provide good via fill and leveling of the deposit tend to worsen the throwing power (TP) of the electroplating bath. TP is defined as the ratio of the deposit copper thickness in the center of the through hole to its thickness at the surface. In this paper an optimization of recently developed innovative, one step acid copper plating technology for filling vias with a minimal surface thickness and plating through holes is presented.
Technical Library | 2021-04-08 00:30:49.0
As the electronic industry moves to lead-free assembly and finer-pitch circuits, widely used printed wiring board (PWB) finish, SnPb HASL, has been replaced with lead-free and coplanar PWB finishes such as OSP, ImAg, ENIG, and ImSn. While SnPb HASL offers excellent corrosion protection of the underlying copper due to its thick coating and inherent corrosion resistance, the lead-free board finishes provide reduced corrosion protection to the underlying copper due to their very thin coating. For ImAg, the coating material itself can also corrode in more aggressive environments. This is an issue for products deployed in environments with high levels of sulfur containing pollutants encountered in the current global market. In those corrosive environments, creep corrosion has been observed and led to product failures in very short service life (1-5 years). Creep corrosion failures within one year of product deployment have also been reported. This has prompted an industry-wide effort to understand creep corrosion
Technical Library | 2021-05-20 13:55:14.0
Quality Control is essential in production processes. In the PCB Assembly process there are several Quality Control steps or options. The most popular tests are the electrical (In-Circuit or ICT) and the function (functional or FCT/FVT) test. ICT test fixtures are standardized and there are several major test platforms available which are industry standards. For FCT applications there are many more variations possible due to the vast number of testers and interface approaches unique to each customer; also due to an endless list of applications which fall under the category of Functional Test (RF, High Current, LED test, Leak test etc.) Test Probes are a very important part in ICT as well as in FCT applications. If the wrong test probe (type, spring force, tip style etc.) is used, the test fixture will not work as intended. In addition the test probe must be installed correctly in order to work properly. This presentation will show general information and some guidelines for a proper Test Fixture design to assure the most efficient production.
