Electronics Manufacturing Technical Articles

3D Printing Electronic Components And Circuits With Conductive Thermoplastic Filament

Jun 02, 2023 | Patrick F. Flowers, Christopher Reyes, Shengrong Ye, Myung Jun Kim, Benjamin J. Wiley

This work examines the use of dual-material fused filament fabrication for 3D printing electronic components
and circuits with conductive thermoplastic filaments. The resistivity of traces printed from
conductive thermoplastic filaments made with carbon-black, graphene, and copper as conductive fillers
was found to be 12, 0.78, and 0.014 ohm cm, respectively, enabling the creation of resistors with values
spanning 3 orders of magnitude. The carbon black and graphene filaments were brittle and fractured
easily, but the copper-based filament could be bent at least 500 times with little change in its resistance.
Impedance measurements made on the thermoplastic filaments demonstrate that the copper-based filament
had an impedance similar to a copper PCB trace at frequencies greater than 1 MHz. Dual material
3D printing was used to fabricate a variety of inductors and capacitors with properties that could be
predictably tuned by modifying either the geometry of the components, or the materials used to fabricate
the components. These resistors, capacitors, and inductors were combined to create a fully 3D
printed high-pass filter with properties comparable to its conventional counterparts. The relatively low
impedance of the copper-based filament enabled its use for 3D printing of a receiver coil for wireless
power transfer. We also demonstrate the ability to embed and connect surface mounted components in
3D printed objects with a low-cost ($1000 in parts), open source dual-material 3D printer. This work thus
demonstrates the potential for FFF 3D printing to create complex, three-dimensional circuits composed
of either embedded or fully-printed electronic components.

Publisher: Duke University

Preparation and Properties of Graphite/Epoxy Resin Conductive Composites

May 30, 2023 | Shan-Shan Yao, Di Jiang, Qi-Zhong Zhang, Xin-Xin Wang

Graphite / epoxy resin conductive composites were prepared by mixing and molding process, using graphite and epoxy resin as raw materials, filling carbon fiber cloth and mixing a small amount of metal powder. We investigated effects on the different ratio of graphite raw materials and the amount of carbon fiber cloth and different metal powder on the resistance and bending strength of graphite / epoxy resin conductive composites. The optimum ratio of raw materials was determined by the experiment. The results showed that the electrical and mechanical properties of the composites were good when the ratio of the two kinds of graphite was 1:1, filling two layers of carbon fiber cloth and the content of aluminum powder was 1%. The resistivity was up to 0.0800 ohm cm, and the bending strength was up to 47.32MPa.

Publisher: Jilin Institute of Chemical Technology

Improvement of the Electrical-Mechanical Performance of Epoxy/Graphite Composites Based on the Effects of Particle Size and Curing Conditions

May 30, 2023 | Hendra Suherman , Radwan Dweiri, Abu Bakar Sulong, Mohd Yusuf Zakaria and Yovial Mahyoedin

This study aims to improve the electrical-mechanical performance of traditional epoxy/graphite composites for engineering applications. The improvement in the properties of these composites depended on the incorporation of different sizes of graphite particles of the same type and controlling their curing process conditions. The thermal properties andmicrostructural changeswere also characterized. A maximum in-plane electrical conductivity value of approximately 23 S/cm was reported for composites containing 80 wt.% G with a particle size of 150 _m. The effect of combining large and small G particles increased this value to approximately 32 S/cm by replacing the large particle size with 10 wt.% smaller particles (75 _m). A further increase in the electrical conductivity to approximately 50 S/cmwas achieved due to the increase in curing temperature and time. Increasing the curing temperature or time also had a crucial role in improving the tensile strength of the composites and a tensile strength of ~19MPa was reported using a system of multiple filler particle sizes processed at the highest curing temperature and time compared to ~9 MPa for epoxy/G150 at 80 wt.%. TGA analysis showed that the composites are thermally stable, and stability was improved by the addition of filler to the resin. A slight difference in the degraded weights and the glass transition temperatures between composites of different multiple filler particle sizes was also observed from the TGA and DSC results.

Publisher: Universitas Bung Hatta

Improved Heat-Spreading Properties Of Fluorinated Graphite/ Epoxy Film

May 30, 2023 | Kyung Hoon Kim, Jeong-In Han, Da-Hee Kang, and Young-Seak Lee

The use of electronic devices has rapidly increased, and such devices are required to be smaller, thinner, lighter, and with higher energy densities than ever before. These requirements can result in the generation of additional heat during device operation, and this heat has detrimental effects on performance, stability, running rate, and lifespan. For instance, if the temperature of an electronic device increases by 2oC when the operating temperature is higher than the stable operating temperature, the stability of the device will be reduced by 10% [1-3]. Thus, the additional heat that such devices generate must be spread to the surrounding environment via heat sinks, coatings, or films with high thermal conductivity.

The use of coatings and films is an appropriate approach for improving the heat spread in electronic devices, particularly as these devices become lighter, smaller, and thinner. Such coatings and films are typically based on polymers such as epoxy, acryl, and polyurethane. Due to the low thermal conductivity of these polymers, it is difficult to use this approach to achieve effective heat spreading. To solve this problem, a great deal of research has addressed the addition of fillers with high thermal conductivity, such as aluminum nitride [4,5], silica (SiO2), alumina (Al2O3), boron nitride [1,6,7], graphite [8], expanded graphite (EG) [9-11], carbon nanotubes (CNTs) [11-13], graphene [9,14,15], and graphene oxide (GO) to polymer-based coatings. Recently, carbon-based materials such as graphite, EG, CNTs, graphene, and GO have been widely investigated because of their low density and high thermal conductivity. However, CNTs and graphene are not appropriate for large-scale applications due to their high production cost and complex processing. In addition, fillers with poor dispersive stability aggregate in coatings form voids, resulting in the degradation of thermal conductivity [16,17]. In this study, anionic fluorine functional groups are introduced into a graphite surface via direct fluorination to increase dispersive stability by generating electrostatic repulsion. We expect the enhanced dispersive stability of the modified graphite to lead to the formation of fewer voids, resulting in improved thermal conductivity of the prepared heat-spreading film.

Publisher: Chungnam National University

Electro-Conductive Resins Filled With Graphite For Casting Applications

May 30, 2023 | Igor Novak, Igor Krupa

Electro-conductive resins, convenient for casting and coating applications were investigated in this paper. Electrical conductivity of epoxy and polyurethane resins, filled with two different grades of synthetic graphite (different average size) was studied. It was found that all the investigated composites became electro-conductive when filled with 22-vol% of the filler. The impact strength of epoxy and polyurethane resins filled with graphite was also investigated. A decrease in impact strength with an increase in filler content was observed in all cases. The highest values of impact strength were found for polyurethane/graphite KS 6 composites. The strength of adhesion of the filled resins to aluminum was also determined. A decrease in the strength of adhesive joints to aluminum foils with an increase in filler content was observed in all cases. The strongest adhesive joints were found for the epoxy/graphite KS 6 composites.

Publisher: Slovak Academy of Sciences

Recent Progress On Thermal Conductivity Of Graphene Filled Epoxy Composites

May 30, 2023 | Ruicong Lv, Yanjuan Ren, Haichang Guo, Shulin Bai

With the rapid development of the electronic industry, the requirements for packaging materials with high thermal conductivity (TC) are getting higher and higher. Epoxy is widely used as package material for electronic package applications. But it's intrinsic TC can't meets the increasing demands. Adding high TC graphene into epoxy matrix is a proper way to reinforce epoxy composites. This review focuses on the filler modification, preparation process and thermal properties of graphene-filled epoxy resin composites. Different ways of covalent and non-covalent modification methods are discussed. The various kinds of graphene coating layer are also summarized. Then we analysis the hybrid filler system in epoxy composite. We hope this review will provide guidance for the development and application of graphene-filled epoxy resin composites.

Publisher: Peking University

在DPC陶瓷基板上如何做碳油厚膜电阻

May 23, 2023 | 斯利通

在DPC陶瓷基板上如何做碳油厚膜电阻...

Publisher: Folysky Technology(Wuhan)Co.,Ltd

QUANTIFYING THE IMPROVEMENTS IN THE SOLDER PASTE PRINTING PROCESS FROM STENCIL NANOCOATINGS AND ENGINEERED UNDER WIPE SOLVENTS

May 22, 2023 | Chrys Shea, Mike Bixenman, T.C. Loy, Debbie Carboni, Brook Sandy-Smith, Greg Wade, Ray Whittier, Joe Perault, Eric Hanson

Over the past several years, much research has been performed and published on the benefits of stencil nano-coatings and solvent under wipes. The process improvements are evident and well-documented in terms of higher print and end-of-line yields, in improved print volume repeatability, in extended under wipe intervals, and in photographs of the stencil's PCB-seating surface under both white and UV light. But quantifying the benefits using automated Solder Paste Inspection (SPI) methods has been elusive at best. SPI results using these process enhancements typically reveal slightly lower paste transfer efficiencies and less variation in print volumes to indicate crisper print definition. However, the improvements in volume data do not fully account for the overall improvements noted elsewhere in both research and in production....

Publisher: KYZEN Corporation

Nanocoating and SMT Stencils

May 22, 2023 | Tecan

With a thickness of no more than 1-100 nanometers, nanocoatings are ultra-thin layers or chemical structures that are applied to surfaces by a variety of methods and applied to a wide range of substrates and chemically bond with non-porous surfaces. To put this in perspective, consider the thickness of paint used in the automotive industry of which is typically 125 microns or 125,000 nanometers.
While they can be one molecule thick, multiple molecular layers can be built up to deliver a particular chemical or physical property to a surface such as water-resistance (hydrophobic) and oil-resistance (oleophobic).

Publisher: tecan

Nanocoatings Webinar & NanoClear® Stencil Treatment

May 22, 2023 | Edward Hughes, ChrysShea

Agenda Overview Independent Testing & Studies-Print studies -Understencil Wipe studies-Durability Testing-Ongoing Studies NanoClear Product Information NanocoatingsComparison Summary Questions...

Publisher: Aculon

NanoClear Coated Stencils

May 22, 2023 | DEK Engineered Products

Our customers' issues • Apertures are getting smaller • Paste does not release as well • Contaminates the bottom of the stencil • Increases defects / reduces yield  Insufficient solder  Bridging  Solder balls on surface of PCB  Flux residue • Requires more frequent cleaning • Reduced efficiency (wasted time) • Increased use of consumables (cost)  USC fabric (use "cheap" fabric to reduce cost)  Lint creates more defects  Cleaning chemistries (use IPA to reduce cost)  IPA breaks down flux and can create more defects...

Publisher: ASM Assembly Systems (DEK)

CHANGING THE RULES OF STENCIL DESIGN

May 22, 2023 | Tony Lentz

Nano-coatings are applied to solder paste stencils with the intent of improving the solder paste printing process. Do they really make a noticeable improvement? The effect of Nano-coatings on solder paste print performance was investigated. Transfer efficiencies were studied across aperture sizes ranging from 0.30 to 0.80 area ratio. Also investigated were the effects of Nano-coatings on transfer efficiencies of tin-lead, lead-free, water soluble, no-clean, and type 3, 4, and 5 solder pastes. Solder paste print performance for each Nano-coating was summarized with respect to all of these variables....

Publisher: FCT ASSEMBLY, INC.

Several ceramic materials are commonly used for the ceramic PCB

May 10, 2023 | 斯利通

Several ceramic materials are commonly used for the ceramic PCB...

Publisher: Folysky Technology(Wuhan)Co.,Ltd

Several ceramic materials are commonly used for the ceramic PCB

May 10, 2023 | 斯利通

Several ceramic materials are commonly used for the ceramic PCB...

Publisher: Folysky Technology(Wuhan)Co.,Ltd

Zirconia ceramic PCB, for applications in the field of microwave communication

May 10, 2023 | 斯利通

Zirconia ceramic PCB, for applications in the field of microwave communication...

Publisher: Folysky Technology(Wuhan)Co.,Ltd

The role that sapphire ceramic PCB play in MEMSdevices

May 10, 2023 | 斯利通

DPC (DirectPlatingCopper) thin film process is a method of prepare copper film using magnetron sputtering technology. This process is a process in which the copper target with the target material is placed in a true cavity chamber, and plasma is generated on the copper target surface by magnetron sputtering technology. The ions in the plasma are bombarded on the surface of the target, which is sputtered into fine particles and deposited on the substrate to form a copper film....

Publisher: Folysky Technology(Wuhan)Co.,Ltd

Electronic Assembly Misprint Cleaning Advancements

May 07, 2023 | Mike Bixenman, Dirk Ellis, Jody Saultz, Eric Becker, Greg Calvo & Jim Morris

Misprint Circuit Assemblies ■ Cleaning misprints is a production gap ■ Commonly cleaned in stencil cleaning equipment ■ Stencil Cleaning equipment allows for the collection and filtration of wet solder paste ■ Stencil Cleaning equipment short comings + Inability to clean B-Side misprints + Poor rinse quality...

Publisher: ITW EAE

First Post - Tell me about your company!

May 05, 2023 | RW

ETC is an OEM manufacturer out of the US.  Our SMT department is high mix, low volume.  We utilize Mycronic mahcines and have production five lines currently; some single machines, others in sequence.  Our maturity with this manufacturing process is about 20 years.  Our products are populated with my100's, 200's, and 300's.

• ~1 million PCAs
  • ~100 million components
    • 700+ unique materials
      • 2,500+ unique smt components

Publisher: ETC, INC.

IMPACT OF 0201 COMPONENTS ON CURRENT MANUFACTURING SYSTEMS

May 02, 2023 | Andrew Butterfield, Mark Guilford, Kevin Pieper

The use of 0201 components in consumer products offers a major competitive advantage over other products since they allow significant design miniaturization. This leads to either smaller products or allows more features integrated into the same package size. One of the critical aspects of having the capability of placing 0201 components in any product is the ability of the manufacturing equipment to handle such small components. Many process studies have been completed by manufacturers and equipment suppliers and have shown that tight process windows are required. The current process control for 0402 components is CpK > 1.5 with a 150μm specification window. For 0201 components, the minimum requirement is CpK > 2.0 with a 100μm specification window. The spec window may need to be reduced down to 75μm if the controls for high volume manufacturing are insufficient. Also directly impacting the placement quality is the ability to apply sufficient solder consistently to the board. The goal is to maintain current printing practices, but the effect of powder size will be examined. This paper will evaluate the impact of placement accuracy and solder powder size on 0201 manufacturing quality....

Publisher: Motorola Mobility LLC.

Board Design and Assembly Process Evaluation for 0201 Components on PCBs

May 02, 2023 | Mei Wang, Dr. Dongkai Shangguan, David Geiger, Kazu Nakajima, CC. Ho, and Sammy Yi

As 0402 has become a common package for printed circuit board (PCB) assembly, research and development on mounting 0201 components is emerging as an important topic in the field of surface mount technology for PWB miniaturization. In this study, a test vehicle for 0201 packages was designed to investigate board design and assembly issues. Design of Experiment (DOE) was utilized, using the test vehicle, to explore the influence of key parameters in pad design, printing, pick-andplace, and reflow on the assembly process. These key parameters include printing parameters, mounting height or placement pressure, reflow ramping rate, soak time and peak temperature. The pad designs consist of rectangular pad shape, round pad shape and home-based pad shape. For each pad design, several different aperture openings on the stencil were included. The performance parameters from this experiment include solder paste height, solder paste volume and the number of post-reflow defects. By analyzing the DOE results, optimized pad designs and assembly process parameters were determined....

Publisher: Flextronics International

PCB Design Optimization of 0201 Packages for Assembly Processes

May 02, 2023 | Mei Wang, Dr. Dongkai Shangguan, David Geiger, Fredrik Mattsson and Sammy Yi

The demand for 0201 components in consumer products will increase sharply over the next few years due to the need for miniaturization. It is predicted that over 20 billion 0201 components will be used in more than one billion cell phones worldwide by the year 2003. Therefore, research and development on 0201 assembly is becoming a very hot topic. The first step to achieve a successful assembly process is to obtain a good PCB design for 0201 packages. This paper presents the data and criteria of PCB design for 0201 packages, including the pad design for 0201 components, and the minimum pad spacing or component clearance between 0201 components or between 0201 and other components. A systematic study on pad design and pad spacing was undertaken, using two test vehicles and three Design of Experiments (DOEs). In the first DOE, 2 out of 18 types of 0201 pad designs were selected based on process yield. The second DOE was focused on pad spacing, including 10mil, 8mil, 6mil and 4mil. The third experiment was final optimization, using two types of optimized pad designs with 10mil, 8mil and 6mil pad spacing. Through the above experiments, the design guideline for PCB layout for 0201 packages and the assembly process capability are identified....

Publisher: Flextronics International

RULES FOR WORKING WITH 0201s AND OTHER SMALL PARTS

May 02, 2023 | Advanced Assembly, LLC

Surface-mount PCB components are smaller than their lead-based counterparts and provide a radically higher component density. They are available in a variety of shapes and sizes designated by a series of standardized codes curated by the electronics industry. Of these PCB components, the 0201-sized are the smallest, measuring 0.024 x 0.012 in. (0.6 x 0.3 mm) – that's 70% smaller than the previous 0402 level! The 0201 components are designed to improve reliability in space-constrained applications such as portable electronics like smartphones, tablets, robotics and digital cameras, but require delicate handling during the assembly process....

Publisher: Advanced Assembly, LLC.

RULES FOR WORKING WITH 0201s AND OTHER SMALL PARTS

May 02, 2023 | Advanced Assembly, LLC

Surface-mount PCB components are smaller than their lead-based counterparts and provide a radically higher component density. They are available in a variety of shapes and sizes designated by a series of standardized codes curated by the electronics industry. Of these PCB components, the 0201-sized are the smallest, measuring 0.024 x 0.012 in. (0.6 x 0.3 mm) – that's 70% smaller than the previous 0402 level! The 0201 components are designed to improve reliability in space-constrained applications such as portable electronics like smartphones, tablets, robotics and digital cameras, but require delicate handling during the assembly process. Given the miniaturized dimensions of an 0201 package, it is crucial that the mounting process abide by a series of guidelines regarding the design of the PCB mounting pads and solderable metallization, PCB circuit trace width, solder paste selection, package placement and overages, solder paste reflow, solder stencil screening, and final inspection. It's advisable that one review this information when procuring the services of a PCB assembler....

Publisher: Advanced Assembly, LLC.

Neo Station: Revolutionize PCB assembly

Apr 29, 2023 | Neotel Technology

The world of electronics is continuously evolving, and the need for faster, more efficient, and more precise assembly of printed circuit boards (PCBs) has become paramount. Neotel Technology's latest innovation, the Neo Station, offers a comprehensive solution for PCB assembly that combines state-of-the-art features with unparalleled ease of use. This document outlines the key features and benefits of the Neo Station, a groundbreaking tool that is set to revolutionize the electronics industry....

Publisher: Neotel Technology Co., Ltd

PWB Contamination & Reliability DOE

Apr 25, 2023 | Michael R. Weekes

This report hopes to achieve several goals: 1. Determine the link between bare PWB contamination, soldered assembly contamination and long-term product reliability. 2. Establish measurable limits for bare PWB cleanliness as well as process control limits for both an aqueous as well as a water-soluble soldering process. 3. Determine whether there is any correlation between common, industry-accepted rose/modified rose (omegameter/ionograph type) testing and long term product reliability. 4. Determine the effect PWB plating finish (HASL, Immersion Silver and Cu OSP) has on both bare PWB contamination as well as soldered assembly in a no clean and water soluble process. 5. Determine whether there is a link between percentage of saponifier used to wash soldered assemblies and long-term reliability. 6. Establish a more cost-effective test for manufacturers to use as a process-monitoring tool.

Publisher: John Deere Electronic Solutions

WHY test for Ionic Contamination?

Apr 17, 2023 | Specialty Coating Systems

Ionic contamination is a leading cause in the degradation and corrosion of electronic assemblies, leading to lifetime limitation and field failure (Fig. 1). Ionic residue comes from a variety of sources shown in Fig. 2 opposite: Examples of ionic contaminants: * Anions * Cations * Weak Organic Acid...

Publisher: Specialty Coating Systems

The Relationship Between Cleanliness and Reliability/Durability

Apr 17, 2023 | Debbie Carboni

Outline/Agenda * Introduction of Ionics and ROSE * Evolution in technology * Rev H in the IPC-J-STD-001 * Real World Case Study * Conclusions...

Publisher: KYZEN Corporation

Comparison of ROSE, C3/IC, and SIR as an effective cleanliness verification test for post soldered PCBA

Apr 17, 2023 | Kong Hui Lee, Rob Jukna, Jim Altpeter, Kantesh Doss

The purpose of this paper is to evaluate and compare the effectiveness and sensitivity of different cleanliness verification tests for post soldered printed circuit board assemblies (PCBAs) to provide an understanding of current industry practice for ionic contamination detection limits. Design/methodology/approach – PCBAs were subjected to different flux residue cleaning dwell times and cleanliness levels were verified with resistivity of solvent extract, critical cleanliness control (C3) test, and ion chromatography analyses to provide results capable of differentiating different sensitivity levels for each test. Findings – This study provides an understanding of current industry practice for ionic contamination detection using verification tests with different detection sensitivity levels. Some of the available cleanliness monitoring systems, particularly at critical areas of circuitry that are prone to product failure and residue entrapment, may have been overlooked. Research limitations/implications – Only Sn/Pb, clean type flux residue was evaluated. Thus, the current study was not an all encompassing project that is representative of other chemistry-based flux residues. Practical implications – The paper provides a reference that can be used to determine the most suitable and effective verification test for the detection of ionic contamination on PCBAs. Originality/value – Flux residue-related problems have long existed in the industry. The findings presented in this paper give a basic understanding to PCBA manufacturers when they are trying to choose the most suitable and effective verification test for the detection of ionic contamination on their products. Hence, the negative impact of flux residue on the respective product's long-term reliability and performance can be minimized and monitored effectively....

Publisher: Jabil Circuit, Inc.

Evaluation of No-Clean Flux Residues Remaining After Secondary Process Operations

Apr 17, 2023 | Phil Isaacs, Jennifer Bennett, Terry Munson

In an ideal world, manufacturing devices would work all of the time, however, every company receives customer returns for a variety of reasons. If these returned parts contributed to a fail, most companies will perform failure analysis (FA) on the returned parts to determine the root cause of the failure. Failure can occur for a multitude of reasons, for example: wear out, fatigue, design issues, manufacturing flaw or defect. This information is then used to improve the overall quality of the product and prevent reoccurrence. If no defect is found, it is possible that in fact the product has no defect. On the other hand, the defect could be elusive and the FA techniques insufficient to detect said deficiency. No-clean flux residues can cause intermittent or elusive, hard to find defects. In an attempt to understand the effects of no-clean flux residues from the secondary soldering and cleaning processes, a matrix of varying process and cleaning operation was investigated. Of special interest, traveling flux residues and entrapped residues were examined, as well as localized and batch cleaning processes. Various techniques were employed to test the remaining residues in order to assess their propensity to cause a latent failure. These techniques include Surface Insulation Resistance1 (SIR) testing at 40⁰C/90% RH, 5 VDC bias along with C32 testing and Ion Exchange Chromatography (IC). These techniques facilitate the assessment of the capillary effect the tight spacing these component structures have when flux residues are present. It is expected that dendritic shorting and measurable current leakage will occur, indicating a failing SIR test. However, since the residue resides under the discrete components, there will be no visual evidence of dendritic growth or metal migration....

Publisher: Foresite Inc.

Characterizing of Emissions from Open Burning of Electronic Waste using TG-GC-MS System

Mar 27, 2023 | Jun Wang

Electronic waste (e-waste) is currently the fastest growing hazardous waste stream that continues to be a challenging concern for the global environment and public health. The average useful life of electronic products has continued to decline, and obsolete products are being stored or discarded with increasing frequency. E-waste is hazardous, complex and expensive to treat in an environmentally sound manner. As a result, new challenges related to the management of e-waste have become apparent. Most electronic products contain a combination of hazardous materials, toxic materials, and valuable elements such as precious metals and rare earth elements. There are risks to human health associated with the disposal of E-waste in landfills, or treatment by incineration. Americans discard 400+ million electronic items per year recycling less than 20 percent in safe and sustainable manner. E-waste is exported from developed countries and processed informally using unsafe conditions in many regions of developing countries. A mixture of pollutants is released from these informal rudimentary operations. Exposure to e-waste recycling includes the dismantling of used electronics and the use of hydrometallurgical and pyrometallurgical processes, which emit toxic chemicals, to retrieve valuable components. Thermal analysis integrated with chromatographic and spectroscopic techniques are used to determine dangerous chemicals emitted during the burning of e-waste. The information is used to assess the risk of exposure of workers at these semi-formal recycling centers....

Publisher: PerkinElmer Optoelectronics

Material & Process Influences on Conductive Anodic Filamentation (CAF)

Mar 16, 2023 | Alun Morgan and Doug Trobough

HISTORY: * In the late 1970s an abrupt unpredictable loss of insulation resistance was observed in PCBs, which were subject to hostile climatic conditions of high relative humidity and temperature while having an applied voltage. * The loss of resistance, even leading to a short circuit was observed to be due to the growth of a subsurface filament from the anode to the cathode. * The term "Conductive Anodic Filamentation" (CAF) was coined....

Publisher: Isola Group

Conductive Anodic Filament (CAF) Formation: A Potential Reliability Problem for Fine-Line Circuits

Mar 16, 2023 | Laura J. Turbini, W. Jud Ready & Brian A. Smith

Outline * Introduction & Background * Factors Affecting CAF Formation * CAF Formation ** Catastrophic Field Failure of Military Hardware ** Laboratory Experiments * Conclusion...

Publisher: Georgia Institute of Technology

Conductive Anodic Filament Failure: A Materials Perspective

Mar 16, 2023 | Laura J. Turbini and W. Jud Ready

Conductive anodic filament (CAF) formation was first reported in 1976.1 This electrochemical failure mode of electronic substrates involves the growth of a copper containing filament subsurface along the epoxy-glass interface, from anode to cathode. Despite the projected lifetime reduction due to CAF, field failures were not identified in the 1980s. Recently, however, field failures of critical equipment have been reported.2 A thorough understanding of the nature of CAF is needed in order to prevent this catastrophic failure from affecting electronic assemblies in the future. Such an understanding requires a comprehensive evaluation of the factors that enhance CAF formation. These factors can be grouped into two types: (1) internal variables and (2) external influences. Internal variables include the composition of the circuit board material, and the conductor metallization and configuration (i.e. via to via, via to surface conductor or surface conductors to surface conductors). External influences can be due to (1) production and (2) storage and use. During production, the flux or hot air solder leveling (HASL) fluid choice, number and severity of temperature cycles, and the method of cleaning may influence CAF resistance. During storage and use, the principal concern is moisture uptake resulting from the ambient humidity. This paper will report on the relationship between these various factors and the formation of CAF. Specifically, we will explore the influences of printed wiring board (PWB) substrate choice as well as the influence of the soldering flux and HASL fluid choices. Due to the ever-increasing circuit density of electronic assemblies, CAF field failures are expected to increase unless careful attention is focused on material and processing choices....

Publisher: Georgia Institute of Technology

Paper Substrates and Inks for Printed Electronics

Mar 13, 2023 | Laura K. Wood†, Erika Hrehorova, Thomas W. Joyce†, Paul D. Fleming, Margaret Joyce†, Alexandra Pekarovicova and Valery Bliznyuk

The present work explores the effects of paper properties on conventional silver-based conducting inks. The effects of smoothness, relative humidity, porosity, permeability and wettability on electrical properties of silver inks on different paper substrates were studied. Another objective of this work was to prepare and study polyaniline synthesized in the presence of different lignosulfonates....

Publisher: Western Michigan University

Printed Electronics: Manufacturing Technologies and Applications

Mar 13, 2023 | Chuck Zhang

Translational Research in Additive Manufacturing at GTMI * Additive manufacturing/3D printing process and equipment development (e.g., metal, polymer and composites part manufacturing) * Computational modeling and simulation of additive manufacturing/printed electronics processes * Advanced materials development for additive manufacturing/printed electronics * Application development and demonstration of additive manufacturing/printed electronics...

Publisher: Georgia Institute of Technology

Modeling Resistance Increase In A Composite Ink Under Cyclic Loading

Mar 13, 2023 | Q Li, E Chung, A Antoniou and O Pierron

The electrical performance of stretchable electronic inks degrades as they undergo cyclic deformation during use, posing a major challenge to their reliability. The experimental characterization of ink fatigue behavior can be a time-consuming process, and models allowing accurate resistance evolution and life estimates are needed. Here, a model is proposed for determining the electrical resistance evolution during cyclic loading of a screen-printed composite conductive ink. The model relies on two input specimen-characteristic curves, assumes a constant rate of normalized resistance increase for a given strain amplitude, and incorporates the effects of both mean strain and strain amplitude. The model predicts the normalized resistance evolution of a cyclic test with reasonable accuracy. The mean strain effects are secondary compared to strain amplitude, except for large strain amplitudes (>10%) and mean strains (>30%). A trace width effect is found for the fatigue behavior of 1 mm vs 2 mm wide specimens. The input specimen-characteristic curves are trace-width dependent, and the model predicts a decrease in Nf by a factor of up to 2 for the narrower trace width, in agreement with the experimental results. Two different methods are investigated to generate the rate of normalized resistance increase curves: uninterrupted fatigue tests (requiring ∼6–7 cyclic tests), and a single interrupted cyclic test (requiring only one specimen tested at progressively higher strain amplitude values). The results suggest that the initial decrease in normalized resistance rate only occurs for specimens with no prior loading. The minimum-rate curve is therefore recommended for more accurate fatigue estimates....

Publisher: Georgia Institute of Technology

An Introduction To The Process Of Printed Electronics

Mar 13, 2023 | S.G.R. Avuthu, Ph.D., M. Gill, N Ghalib, M. Sussman, G. Wable, J. Richstein, Ph.D.

Printed electronics (PE) is impacting almost every branch of manufacturing. The printing of electronics on mechanically flexible substrates such as plastic, paper and textile, using traditional printing techniques, provides novel applications for wearable and stretchable electronics. Government sponsored consortiums, universities, contract printers, startups and global manufacturers are developing processes to bring this technology to market faster, more costeffectively and at scale. By increasing the speed of technology adoption while following industrialization best practices, industry researchers aim to create processes that ramp up the scale of production for simple circuits and integrated conductive structures....

Publisher: Jabil Circuit, Inc.

Printable Electronics: Towards Materials Development And Device Fabrication

Mar 13, 2023 | Rabindra N. Das, How T. Lin, John M. Lauffer and Voya R. Markovich

Purpose – There has been increasing interest in the development of printable electronics to meet the growing demand for low-cost, large-area, miniaturized, flexible and lightweight devices. The purpose of this paper is to discuss the electronic application of novel printable materials. Design/methodology/approach – The paper addresses the utilization of polymer nanocomposites as it relates to printable and flexible technology for electronic packaging. Printable technology such as screen-printing, ink-jet printing, and microcontact printing provides a fully additive, non-contacting deposition method that is suitable for flexible production....

Publisher: i3 Electronics

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Mar 04, 2023 | Management representative

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Publisher: Hiflo Solders Private Limited

PCB terminology you must know

Feb 28, 2023 | FS PCBA

With the popularization of electronic products, more and more people know the importance of printed circuit board (PCB), but it is a very complicated and huge knowledge system. In this article, we will discuss some terms about the PCB industry so that you can better understand the circuit board. Printed circuit board professional noun Array: Usually we also refer to it as panelized, stepped or palletized PCB, which refers to the combination of multiple copies of the PCB into a connected matrix of circuit boards. Usually we refer to the PCB as the bare board of the circuit board, that is, the part that does not contain components, it is not working, and the electronics manufacturer needs to find a suitable PCBA processing plant to complete the assembly after completing the PCB manufacturing. Through the above-mentioned assembly method, PCBA company can complete the assembly work faster. https://www.fs-pcba.com/ Board Aspect Ratio: It is the ratio between board thickness and minimum via diameter, which is very important. We know that a circuit board is an electronic product that contains circuit images, and the circuit diagrams are formed during production through methods such as SUV exposure. In order to ensure the accuracy of circuit images and assembly work, designers need to ensure a lower aspect ratio to reduce potential risks that may arise. Cable: It is used for the transmission of electric current just like the wires in our daily life. There are various wires in electronic products, these wires connect different components, and they are electrically connected to each other to operate. https://www.fs-pcba.com/manufacturing-pcb/ Main body: As mentioned above, the PCB board cannot operate alone, but the components are mounted on the surface of the bare board through PCB assembly. These components are very small, but when they are installed, there are many extra parts such as: pins, leads and accessories. In order to accurately express their views, designers usually use the main body of the component to represent the central part of the electronic component. https://www.fs-pcba.com/assembly-pcb/ More Interesting Board Articles The PCB industry involves a lot of content. In order to complete a complete PCBA board, we need to go through multiple links, such as design, manufacturing, assembly, testing, etc., and there are more categories under each link. If you want to know more about this industry, it will be helpful for you to read more about PCB....

Publisher: FS Technology

Printed Circuit Board (PCB) Micro-Sectioning For Quality Control

Feb 27, 2023 | Nanu Vahora

Quality control in Printed Circuit Board (PCB) manufacturing is very important, including but not limited to drilling hole quality, Desmearing of drilled hole, plating thickness of various metals and integrating of the final production board. During the manufacture of printed circuit boards, test coupons are introduced in each production panel. This allows each panel to be tested without wasting actual production board. The coupon is separated from the panel to confirm product specifications have been met.

Publisher: Buehler, a division of Illinois Tool Works Inc.

ALD Atomic Layer Deposition for space applications

Feb 19, 2023 | Marko Pudas

ALD – Atomic Layer Deposition

- Is a batch coating process with surface chemistry
- Wide range of material, e.g. Al2O3, TiO2, M-, M-C,M-N
- Typical; 100 nm up to ~0,5 μm
- True 3D down to nanopores, no pinholes
- Vacuum deposition process
-- Substrates are degassed & heated (degas analyzed)
-- ~40 C – 125C – 400 C
- Mature IC manufacturing process
- Extremely repeatable in thickness & quality over time
- Chemically adhesion; will not peal off/flak
-- Dense,
-- Pinhole- and defect-free films
-- Digitally repeatable process

Publisher: Picosun Oy

Atomic Layer Deposition (ALD) to Mitigate Tin Whisker Growth and Corrosion Issues on Printed Circuit Board Assemblies

Feb 19, 2023 | TERHO KUTILAINEN, MARKO PUDAS, MARK A. ASHWORTH , TERO LEHTO, LIANG WU, GEOFFREY D. WILCOX, JING WANG, PAUL COLLANDER, and JUSSI HOKKA

This paper presents the results of a research program set up to evaluate atomic layer deposition (ALD) conformal coatings as a method of mitigating the growth of tin whiskers from printed circuit board assemblies. The effect of ALD coating process variables on the ability of the coating to mitigate whisker growth were evaluated. Scanning electron microscopy and optical microscopy were used to evaluate both the size and distribution of tin whiskers and the coating/whisker interactions. Results show that the ALD process can achieve significant reductions in whisker growth and thus offers considerable potential as a reworkable whisker mitigation strategy. The effect of ALD layer thickness on whisker formation was also investigated. Studies indicate that thermal exposure during ALD processing may contribute significantly to the observed whisker mitigation....

Publisher: Poltronic Inc

Investigation of the Atomic Layer Deposition of the Titanium Dioxide (TiO2) Film as pH Sensor Using a Switched Capacitor Amplifier

Feb 19, 2023 | Mozhdeh Nematzadeh , Ola Nilsen , Philipp Dominik Häfliger and Veronica Anne-Line Kathrine Killi

The electrical and chemical properties of the titanium dioxide (TiO2) coated spirals grown by the atomic layer deposition (ALD) technique in two different temperatures of 150 °C and 300 °C are studied. The thickness of the TiO2 layers studied are 20, 40, and 80 nm. A switched capacitor amplifier is used to investigate the pH response and the capacitance of the samples. It is found that the performance of the TiO2 samples depends on either the thickness or the deposition temperature due to the differences in the physical properties of the oxide layer such as surface roughness and film density. The high temperature samples are more crystalline, whereas the low temperature samples are more amorphous. Since there is a low pass filter effect in the electrolyte–sample interface, the TiO2 coated samples show the better response to the pH change for the high temperature samples as the sensor surface area for binding the hydrogen ions is larger and the charge transfer resistance is smaller. Furthermore, more roughness on the surface can be obtained by increasing the thickness, which reduces the charge transfer resistance. In this study, the 80 nm sample deposited at 300 °C gives the best pH response of 40 mV/pH.

Publisher: University of Oslo

Atomic Layer Deposition for Encapsulation and Hermetic Sealing of RF and Power Electronics

Feb 19, 2023 | Forge Nano

Radio frequency (RF) and power electronics are vital to an array of industries, from telecom and consumer electronics to transportation and energy distribution. As energy diversification and the prevalence of high-speed electronics continue to grow, RF and power electronics are expected to reach a global market of $36.6 billion by 2027.1 Extreme environments such as high temperatures, ultra-violet radiation, oxygen, salinity and moisture are all threats that degrade and corrode active components causing early failure. Atomic layer deposition (ALD) has created substantial improvements to the reliability and performance of RF and power electronics. Using ALD as an encapsulation layer at the wafer level or as a final hermetic seal at the chip/module/PCB level has been shown to substantially improve electronic performance and lifetime.2,3 ALD layers enable longer lifetimes, higher performance and lower cost without adding the considerable mass gain and high temperature processing associated with conventional hermetic coatings.

Publisher: Forge Nano

Potting-optimized component design

Feb 15, 2023 | Scheugenpflug

With regard to potting, the design of electronic assemblies and components has a significant impact on economical and sustainable production. Key aspects in this respect are pottability, material use, cycle times, quality and the process technology needed. Optimized, bubble-free potting contributes greatly to the function and longevity of products. It is best practice during the design and development phases therefore to follow the potting tips contained in this White Paper....

Publisher: Scheugenpflug Inc.

Generation of Sn Whiskers During Electrodeposition

Feb 13, 2023 | M. Saitou

Sn whiskers generated during electrodeposition on a Cu plate within a range of the deposition temperature from 273 to 303 K were investigated using scanning electron microscopy and X-ray diffraction. The critical film thickness for the formation of Sn whiskers on a Sn thin film was determined (1.9 um). The critical film thickness was found to be independent of the deposition temperature. At the film thicknesses more than 5 um, the (220) dominant crystallographic plane transformed the (112) plane parallel to the Cu plate. This can be attributed to the morphological change (coarse to dense Sn whiskers). This suggests that the Sn whiskers with the (220) plane acted as crystal seeds to generate the Sn whiskers with the (112) plane. The fine string-like Sn whiskers generated at 303 K during the electrodeposition showed an anomalous growth rate of 45 nm s-1 at least.

Publisher: University of the Ryukyus

Effects of Tin Whisker Formation on Nanocrystalline Copper

Feb 13, 2023 | David M. Lee, Lesly A. Piñol

Spontaneously forming tin whiskers, which emerge unpredictably from pure tin surfaces, have regained prevalence as a topic within the electronics research community. This has resulted from the ROHS-driven conversion to "lead-free" solderable finish processes. Intrinsic stresses (and/or gradients) in plated films are considered to be a primary driving force behind the growth of tin whiskers. This paper compares the formation of tin whiskers on nanocrystalline and conventional polycrystalline copper deposits. Nanocrystalline copper under-metal deposits were investigated, in terms of their ability to mitigate whisker formation, because of their fine grain size and reduced film stress. Pure tin films were deposited using matte and bright electroplating, electroless plating, and electron beam evaporation. The samples were then subjected to thermal cycling conditions in order to expedite whisker growth. The resultant surface morphologies and whisker formations were evaluated....

Publisher: Johns Hopkins Applied Physics Laboratory

DoD/EPA/DOE SERDP WP-2213: Novel Whisker Mitigating Composite Conformal Coat Assessment

Feb 13, 2023 | Dr. Stephan Meschter, Dr. Polina Snugovsky, Dr. Abdullah Ekin, Dale Starkey,Dr. Junghyun Cho

Technology Focus: Develop and evaluate nanoparticle filled conformal coatings designed to provide long term whisker penetration resistance and coverage on tin rich metal surfaces prone to whisker growth in commercial lead-free electronics used in modern DoD systems. Research Objectives: Identify the fundamental mechanisms by which conformal coatings provide long-term tin whisker penetration resistance and inhibit nucleation/growth. Correlate mechanical properties and coverage thickness to whisker penetration resistance. Project Progress and Results: Functionalized nanosilica and non-functional nanoalumina enhanced polyurethane conformal coatings have shown improved spray coating coverage characteristics and crack resistance during thermal cycling fatigue testing. Lead-free assembly whisker mitigation validation testing is in process. Technology Transition: Current project partners provide coating materials to industry. SERDP test data will be considered during updates to the DoD adopted IPC standards for coating materials and coverage....

Publisher: BAE SYSTEMS

Strategies To Mitigate The Tin Whisker Phenomenon

Feb 13, 2023 | Patrick Laver

The tin whisker phenomenon is a failure mode associated with all electronic devices that use a number of low melting point elements (e.g., Sn, Cd, In) in operations such as soldering. Recognized many years ago, the problem was minimized by adding lead, now identified as a hazardous substance and banned...

Publisher: Vicor Corporation