Electronics Manufacturing Technical Articles

Papers and articles related to SMT, PCB & EMS industry.

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1757 SMT / PCB Assembly Related Technical Articles

Reworking ALD Coatings

Sep 02, 2020 | ACI Technologies, Inc.

Atomic layer deposition (ALD) is a process of creating coatings on a molecular layer by layer basis. Using an iterated sequence of self-saturating deposition cycles that are self-terminating, a single layer can be deposited at a time, allowing for highly uniform films with complete conformality. The composition of the film typically used for coating printed wiring boards (PWBs) is a high alumina (Al2O3) sequential deposition of alumina and titania capped with a corrosion protective titanium aluminate layer, most notably ALD-Cap from Sundew Technologies, LLC. Rework is a process of restoring an electronics assembly to full functionality to prolong equipment life and reduce the amount of scrap. The process typically involves:...

Publisher: ACI Technologies, Inc.

ACI Technologies, Inc.

ACI, an authorized IPC Training Center operating the National Electronics Manufacturing Center of Excellence providing analytical testing, manufacturing and repair services to the electronics industry.

Philadelphia, Pennsylvania, USA

Consultant / Service Provider, Standards Setting / Certification, Training Provider

Approaches to Overcome Nodules and Scratches on Wire Bondable Plating on PCBs

Aug 27, 2020 | Young K. Song and Vanja Bukva and Ryan Wong

Initially adopted internal specifications for acceptance of printed circuit boards (PCBs) used for wire bonding was that there were no nodules or scratches allowed on the wirebond pads when inspected under 20X magnification. The nodules and scratches were not defined by measurable dimensions and were considered to be unacceptable if there was any sign of a visual blemish on wire-bondable features. Analysis of the yield at a PCB manufacturer monitored monthly for over two years indicated that the target yield could not be achieved, and the main reasons for yield loss were due to nodules and scratches on the wirebonding pads. The PCB manufacturer attempted to eliminate nodules and scratches. First, a light-scrubbing step was added after electroless copper plating to remove any co-deposited fine particles that acted as a seed for nodules at the time of copper plating. Then, the electrolytic copper plating tank was emptied, fully cleaned, and filtered to eliminate the possibility of co-deposited particles in the electroplating process. Both actions greatly reduced the density of the nodules but did not fully eliminate them. Even though there was only one nodule on any wire-bonding pad, the board was still considered a reject. To reduce scratches on wirebonding pads, the PCB manufacturer utilized foam trays after routing the boards so that they did not make direct contact with other boards. This action significantly reduced the scratches on wire-bonding pads, even though some isolated scratches still appeared from time to time, which caused the boards to be rejected. Even with these significant improvements, the target yield remained unachievable. Another approach was then taken to consider if wire bonding could be successfully performed over nodules and scratches and if there was a dimensional threshold where wire bonding could be successful. A gold ball bonding process called either stand-off-stitch bonding (SSB) or ball-stitch-on-ball bonding (BSOB) was used to determine the effects of nodules and scratches on wire bonds. The dimension of nodules, including height, and the size of scratches, including width, were measured before wire bonding. Wire bonding was then performed directly on various sizes of nodules and scratches on the bonding pad, and the evaluation of wire bonds was conducted using wire pull tests before and after reliability testing. Based on the results of the wire-bonding evaluation, the internal specification for nodules and scratches for wirebondable PCBs was modified to allow nodules and scratches with a certain height and a width limitation compared to initially adopted internal specifications of no nodules and no scratches. Such an approach resulted in improved yield at the PCB manufacturer....

Publisher: Teledyne DALSA

Teledyne DALSA

Established in 1980 and acquired by Teledyne Technologies in 2011, Teledyne DALSA designs, develops, manufactures, and markets digital imaging products and solutions, in addition to providing semiconductor products and services.

Waterloo, Ontario, Canada

Other

An Automatic Surface Defect Inspection System for Automobiles Using Machine Vision Methods

Aug 27, 2020 | Qinbang Zhou , Renwen Chen, Bin Huang, Chuan Liu, Jie Yu and Xiaoqing Yu

Automobile surface defects like scratches or dents occur during the process of manufacturing and cross-border transportation. This will affect consumers' first impression and the service life of the car itself. In most worldwide automobile industries, the inspection process is mainly performed by human vision, which is unstable and insufficient. The combination of artificial intelligence and the automobile industry shows promise nowadays. However, it is a challenge to inspect such defects in a computer system because of imbalanced illumination, specular highlight reflection, various reflection modes and limited defect features. This paper presents the design and implementation of a novel automatic inspection system (AIS) for automobile surface defects which are the located in or close to style lines, edges and handles. The system consists of image acquisition and image processing devices, operating in a closed environment and noncontact way with four LED light sources. Specifically, we use five plane-array Charge Coupled Device (CCD) cameras to collect images of the five sides of the automobile synchronously. Then the AIS extracts candidate defect regions from the vehicle body image by a multi-scale Hessian matrix fusion method. Finally, candidate defect regions are classified into pseudo-defects, dents and scratches by feature extraction (shape, size, statistics and divergence features) and a support vector machine algorithm. Experimental results demonstrate that automatic inspection system can effectively reduce false detection of pseudo-defects produced by image noise and achieve accuracies of 95.6% in dent defects and 97.1% in scratch defects, which is suitable for customs inspection of imported vehicles....

Publisher: Nanjing University

Nanjing University

Located in the ancient capital of Nanjing, Nanjing University and its predecessors have taken responsibility for the country and the nation during its development of over 100 years. Committed to the prosperity of the nation ...

Nanjing, Jiangsu, China

Research Institute / Laboratory / School

All-in-One, Wireless, Stretchable Hybrid Electronics for Smart, Connected, and Ambulatory Physiological Monitoring

Aug 19, 2020 | Yun-Soung Kim, Musa Mahmood, Yongkuk Lee, Nam Kyun Kim, Shinjae Kwon, Robert Herbert, Donghyun Kim, Hee Cheol Cho,* and Woon-Hong Yeo*

Commercially available health monitors rely on rigid electronic housing coupled with aggressive adhesives and conductive gels, causing discomfort and inducing skin damage. Also, research-level skin-wearable devices, while excelling in some aspects, fall short as concept-only presentations due to the fundamental challenges of active wireless communication and integration as a single device platform. Here, an all-in-one, wireless, stretchable hybrid electronics with key capabilities for real-time physiological monitoring, automatic detection of signal abnormality via deep-learning, and a long-range wireless connectivity (up to 15 m) is introduced. The strategic integration of thin-film electronic layers with hyperelastic elastomers allows the overall device to adhere and deform naturally with the human body while maintaining the functionalities of the on-board electronics. The stretchable electrodes with optimized structures for intimate skin contact are capable of generating clinical-grade electrocardiograms and accurate analysis of heart and respiratory rates while the motion sensor assesses physical activities. Implementation of convolutional neural networks for real-time physiological classifications demonstrates the feasibility of multifaceted analysis with a high clinical relevance. Finally, in vivo demonstrations with animals and human subjects in various scenarios reveal the versatility of the device as both a health monitor and a viable research tool....

Publisher: Georgia Institute of Technology

Georgia Institute of Technology

Center for Board Assembly Research CBAR- advanced research on board assembly processes and systems

Atlanta, Georgia, USA

Research Institute / Laboratory / School

An Engineer's Guide to Testing and Evaluating The Performance of Desiccant Bags for the Protection of Critical Moisture Sensitive Devices

Aug 16, 2020 | Dan Jenkins

Not all desiccant bags are created or perform equally. Performance measures include: a) How long does desiccant last? b) How much are can be desiccated in a given area? c) How much moisture is retained, and or released back into the atmosphere? This article walks engineers through various test they can perform to determine efficacy. Additionally, the article highlight between adsorption vs adsorption....

Publisher: Steel Camel

Steel Camel

Super powerful expanding desiccant to keep boards & microelectronics moisture free.... Much different than Silica Sand Beads. Also supplier of corrosion prevention treatments that are alternatives to Conformal coatings.

Tampa, Florida, USA

Other

Best Practices in Selecting Coatings and Pottings for Solar Panel Systems; Junction Boxes and Inverters

Aug 13, 2020 | Greg Caswell [DfR], Matt Perry [H.B. Fuller], Haichuan Zhao [H.B. Fuller], Ralph Velazquez [H.B. Fuller]

The solar industry has driven solutions that result in electronics systems that are required to perform in outside environments for over 25 years. This industry expectation has resulted in solutions to protect the electronics from failure that can result from interaction with moisture, and various chemicals leading to corrosion and shorting of the systems. Potting and encapsulation compounds can impart the very high level of protection from environmental, thermal, chemical, mechanical, and electrical conditions that the solar applications demand....

Publisher: DfR Solutions (acquired by ANSYS Inc)

DfR Solutions (acquired by ANSYS Inc)

DfR Solutions has world-renowned expertise in applying the science of Reliability Physics to electrical and electronics technologies, and is a leading provider of quality, reliability, and durability (QRD) research and consulting

College Park,

Consultant / Service Provider

Additive Manufacturing for Next Generation Microwave Electronics and Antennas

Aug 13, 2020 | Xuanke He, Bijan K. Tehrani, Ryan A. Bahr, Manos Tentzeris

The paper will discuss the integration of 3D printing and inkjet printing fabrication technologies for microwave and millimeter-wave applications. With the recent advancements in 3D and inkjet printing technology, achieving resolution down to 50 um, it is feasible to fabricate electronic components and antennas operating in the millimeter-wave regime. The nature of additive manufacturing allows designers to create custom components and devices for specialized applications and provides an excellent and inexpensive way of prototyping electronic designs. The combination of multiple printable materials enables the vertical integration of conductive, dielectric, and semi-conductive materials which are the fundamental components of passive and active circuit elements such as inductors, capacitors, diodes, and transistors. Also, the on-demand manner of printing can eliminate the use of subtractive fabrication processes, which are necessary for conventional microfabrication processes such as photolithography, and drastically reduce the cost and material waste of fabrication....

Publisher: Georgia Institute of Technology

Georgia Institute of Technology

Center for Board Assembly Research CBAR- advanced research on board assembly processes and systems

Atlanta, Georgia, USA

Research Institute / Laboratory / School

RELIABLE NICKEL-FREE SURFACE FINISH SOLUTION FOR HIGHFREQUENCY-HDI PCB APPLICATIONS

Aug 05, 2020 | Kunal Shah, Ph.D.

The evolution of internet-enabled mobile devices has driven innovation in the manufacturing and design of technology capable of high-frequency electronic signal transfer. Among the primary factors affecting the integrity of high-frequency signals is the surface finish applied on PCB copper pads – a need commonly met through the electroless nickel immersion gold process, ENIG. However, there are well-documented limitations of ENIG due to the presence of nickel, the properties of which result in an overall reduced performance in high-frequency data transfer rate for ENIG-applied electronics, compared to bare copper. An innovation over traditional ENIG is a nickel-less approach involving a special nano-engineered barrier designed to coat copper contacts, finished with an outermost gold layer. In this paper, assemblies involving this nickel-less novel surface finish have been subjected to extended thermal exposure, then intermetallics analyses, contact/sheet resistance comparison after every reflow cycle (up to 6 reflow cycles) to assess the prevention of copper atoms diffusion into gold layer, solder ball pull and shear tests to evaluate the aging and long-term reliability of solder joints, and insertion loss testing to gauge whether this surface finish can be used for high-frequency, high density interconnect (HDI) applications....

Publisher: LiloTree

LiloTree

LiloTree is an advanced materials technology company, providing next-generation technology solutions through chemistry and materials innovations. Based in Seattle, Washington, we're an NSF funded company, manufacturer & distrib...

Redmond, Washington, USA

Manufacturer

Selection of PCB Materials for 5G

Aug 05, 2020 | John Coonrod

With the first 5G NR standard recently approved by the 3GPP at the end of 2017, many companies are racing to design 5G radio products that will demand wider bandwidths, higher frequencies, enhanced carrier aggregation and support of massive MIMO. AT&T and Samsung plan to launch 5G mobile services and Verizon plans to launch 5G Fixed Wireless Access in the US this year while South Korea will be demonstrating 5G at the upcoming Winter Olympics....

Publisher: Rogers Corporation

Rogers Corporation

Rogers' high performance laminates and bondplies are engineered to meet stringent customer requirements for 5G wireless communication, wired infrastructure, automotive radar sensors, aerospace, satellites and more.

Chandler, Arizona, USA

Manufacturer

ALD of Alumina Ceramic Films for Hermetic Protection

Aug 05, 2020 | ACI Technologies, Inc.

A primary issue in electronics reliability for military applications is the ability to ensure long term operability in harsh, extreme environments. This requires more rigid standards, such as the MIL-STD-883 (Department of Defense Test Method Standard for Microcircuits), which commercial grade electronics typically do not satisfy. A solution commonly employed is to package the critical electronic components in hermetically sealed metal or ceramic enclosures which are costly and labor intensive. Not only are the components more expensive, but the assembly process is more difficult to automate, resulting in a substantial cost premium for military grade electronics....

Publisher: ACI Technologies, Inc.

ACI Technologies, Inc.

Philadelphia, Pennsylvania, USA

Consultant / Service Provider, Standards Setting / Certification, Training Provider

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