Electronics Manufacturing Technical Articles

Reliable Young's Modulus Value of High Flexible, Treated Rolled Copper Foils Measured by Resonance Method

Aug 15, 2018 | Kazuki Kammuri, Atsushi Miki, Hiroki Takeuchi

Smartphones and tablets require very high flexibility and severe bending performance ability of the flexible printed circuits (FPCs) to fit into their thinner and smaller body designs. In these FPCs, the extraordinary highly flexible, treated rolled-annealed (RA) copper foils have recently used instead of regular RA foil and electro deposited foils. It is very important to measure the Young's moduli of these foils predicting the mechanical properties of FPCs such as capabilities of fatigue endurance, folding, and so on. Even though the manufacturers use IPC TM-650 2.4.18.3 test method for measuring Young's modulus of copper foils over many years, where Young's modulus is calculated from the stress–strain (S–S) curve, it is quite difficult to obtain the accurate Young's modulus of metal foils by this test method....

Publisher: JX Nippon Mining & Metals

New Phosphorus-based Curing Agents for PWB

Aug 08, 2018 | A. Piotrowski, M. Zhang, S. Levchik - ICL-IP, Y. Zilberman, Eran Gluz - IMI

As a result of the continuous industrial trend towards high density packaging there is a growing demand for highly thermally-stable laminate materials. Although the epoxy resin defines the thermal stability, often the flame retardant used becomes the limiting factor in achieving a higher stability. Recognizing this industrial need, the company has developed a new flame-retardant curing agent, Material A. This is a phosphorus-based polymer which cures epoxy via a very specific mechanism. Common Novolac epoxy resins cured with Material A and a phenol-formaldehyde resin show a Tg >180 °C and Td >400 °C. In addition to a high thermal stability, Material A also shows a dielectric loss factor lower than commercial phosphorus-based flame retardants....

Publisher: ICL-IP

Best Practices for Improving the PCB Supply Chain: Performing the Process Audit

Aug 03, 2018 | Greg Caswell, Dr. Craig Hillman

In the electronics industry, the quality and reliability of any product is highly dependent upon the capabilities of the manufacturing suppliers. Manufacturing defects are one of the top reasons why companies fail to meet warranty expectations. These problems can result in severe financial pain and eventual loss of market share. What a surprising number of engineers and managers fail to realize is that focusing on processes addresses only part of the issue. Supplier selection also plays a critical role in the success or failure of the final product....

Publisher: DfR Solutions (acquired by ANSYS Inc)

Early Design Review of Boundary Scan in Enhancing Testability and Optimization of Test Strategy

Aug 01, 2018 | Sivakumar Vijayakumar

With complexities of PCB design scaling and manufacturing processes adopting to environmentally friendly practices raise challenges in ensuring structural quality of PCBs. This makes it essential to have a good 'Design for Test' (DFT) to ensure a robust structural test. (...)

During the course of the DFT review, can we realize a good test strategy for the PCBA. How can the test strategy of the PCBA be partitioned as to what portions of the design can be covered structurally and what is covered functionally, in a way that provides best diagnostics to discover faults...

Publisher: Keysight Technologies

Expanding IEEE Std 1149.1 Boundary-Scan Architecture Beyond Manufacturing Test of Printed Circuit Board Assembly

Jul 25, 2018 | Jun Balangue

This paper will discuss the expanded use of boundary-scan testing beyond the typical manufacturing test to capture structural defects on a component/devices in a printed circuit board assembly (PCBA). The following topics will be discussed to demonstrate the capability of boundary-scan test system on how we can extend beyond typical manufacturing test: Boundary-scan as a complete manufacturing test system, Boundary-scan implementation during PCBA design stage, Implementation of boundary-scan beyond typical structural testing...

Publisher: Keysight Technologies

Improve SMT Assembly Yields Using Root Cause Analysis in Stencil Design

Jul 18, 2018 | Greg Smith

Reduction of first pass defects in the SMT assembly process minimizes cost, assembly time and improves reliability. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining a successful and profitable assembly process. It is commonly accepted that the solder paste printing process causes the highest percentage of yield challenges in the SMT assembly process. As form factor continues to get smaller, the challenge to obtain 100% yield becomes more difficult.

This paper will identify defects affecting SMT yields in the printing process and discuss their Root Cause. Outer layer copper weight and surface treatment will also be addressed as to their effect on printability. Experiments using leadless and emerging components will be studied and root cause analysis will be presented...

Publisher: FCT ASSEMBLY, INC.

Improving Thermal Cycle and Mechanical Drop Impact Resistance of a Lead-free Tin-Silver-Bismuth-Indium Solder Alloy with Minor Doping of Copper Additive

Jul 11, 2018 | Takehiro Wada, Seiji Tsuchiya, Shantanu Joshi, Roberto Garcia, Kimiaki Mori, Takeshi Shirai

For a demanding automotive electronics assembly, a highly thermal fatigue resistant solder alloy is required, which makes the lead-free Sn-Ag-Cu type solder alloy unusable. Sn-Ag-Bi-In solder alloy is considered as a high reliability solder alloy due to significant improvement in thermal fatigue resistance as compared to a standard Sn-Ag-Cu alloy. The alloy has not only good thermal fatigue properties but it also has superior ductility and tensile strength by appropriate addition of In; however, initial results indicated a sub-par performance in joint reliability when it is soldered on a printed circuit board (PCB) with Electroless Nickel Immersion Gold (ENIG) surface finish. Numerous experiments were performed to find out appropriate alloying element which would help improve the performance on ENIG PCBs. Sn-Ag-Bi-In solder alloys with and without Cu additions were prepared and then tests were carried out to see the performance in a thermal fatigue test and a drop resistance test.to investigate the impact of Cu addition towards the improvement of joint reliability on ENIG finish PCB. Also, the mechanism of such improvement is documented....

Publisher: Koki Company LTD

Inkjet-Printed and Paper-Based Electrochemical Sensors

Jul 03, 2018 | Ryan P. Tortorich, Hamed Shamkhalichenar, Jin-Woo Choi

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...

Publisher: Louisiana State University

Flexible Hybrid Circuit Fully Inkjet-Printed: Surface Mount Devices Assembled By Silver Nanoparticles-Based Inkjet Ink

Jun 27, 2018 | J. Arrese, G. Vescio, E. Xuriguera, B. Medina-Rodriguez, A. Cornet, and A. Cirera

Nowadays, inkjet-printed devices such as transistors are still unstable in air and have poor performances. Moreover, the present electronics applications require a high degree of reliability and quality of their properties. In order to accomplish these application requirements, hybrid electronics is fulfilled by combining the advantages of the printing technologies with the surface-mount technology.

In this work, silver nanoparticle-based inkjet ink (AgNP ink) is used as a novel approach to connect surface-mount devices (SMDs) onto inkjet-printed pads, conducted by inkjet printing technology...

Publisher: Universitat de Barcelona

Design for Testability (DFT) to Overcome Functional Board Test Complexities in Manufacturing Test

Jun 20, 2018 | Louis Y. Ungar

Manufacturers test to ensure that the product is built correctly. Shorts, opens, wrong or incorrectly inserted components, even catastrophically faulty components need to be flagged, found and repaired. When all such faults are removed, however, functional faults may still exist at normal operating speed, or even at lower speeds. Functional board test (FBT) is still required, a process that still relies on test engineers’ understanding of circuit functionality and manually developed test procedures. While functional automatic test equipment (ATE) has been reduced considerably in price, FBT test costs have not been arrested. In fact, FBT is a huge undertaking that can take several weeks or months of test engineering development, unacceptably stretching time to market. The alternative, of selling products that have not undergone comprehensive FBT is equally, if not more, intolerable....

Publisher: A.T.E. Solutions, Inc.