Electronics Manufacturing Technical Articles

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

Whisker Formation Induced by Component and Assembly Ionic Contamination

Feb 13, 2023 | POLINA SNUGOVSKY, STEPHAN MESCHTER, ZOHREH BAGHERI, EVA KOSIBA, MARIANNE ROMANSKY, and JEFFREY KENNEDY

This paper describes the results of an intensive whisker formation study on Pb-free assemblies with different levels of cleanliness. Thirteen types of as-received surface-mount and pin-through-hole components were cleaned and intentionally contaminated with solutions containing chloride, sulfate, bromide, and nitrate. Then the parts were assembled on double-sided boards that were also cleaned or intentionally contaminated with three fluxes having different halide contents. The assemblies were subjected to high-temperature/high-humidity testing (85_C/85% RH). Periodic examination found that contamination triggered whisker formation on both exposed tin and solder fillets. Whisker occurrence and parameters depending on the type and level of contamination are discussed. Cross-sections were used to assess the metallurgical aspects of whisker formation and the microstructural changes occurring during corrosion....

Publisher: Celestica Corporation

Via Hole Filling Technology for High Density, High Aspect Ratio Printed Wiring Boards Using a High Tg, low CTE Plugging Paste

Feb 06, 2023 | Michael Carano

The continued fast pace towards miniaturization is leading circuit board designers to push the envelope on integration density. This trend is driving fabricators to closely look at methods and processes that will enable the move towards sequential lamination and blind and buried via technology. Circuit board fabricators particularly in North America are adopting techniques such as via filling capability with nonconductive, high Tg, low CTE plugging pastes. This paper describes the implementation of the via filling process in a highly effective and reliable fashion for high density, high aspect ratio printed wiring boards. Close attention is paid to use of these via filling materials under high temperature assembly conditions. In addition, via plugging material requirements, equipment considerations and process limitations will be presented. Further, the pros and cons of different filling techniques are discussed. Finally, desmear and metallization techniques to insure adhesion of the plating to the filled via are presented in the context of “Best Practices.”

Publisher: Omg Electrochemicals / Macdermid Alpha

PCB Quality Metrics that Drive Reliability

Jan 23, 2023 | Bhanu Sood, Ph.D.

PDC Outline Section 0: Intro Section 1: What is reliability and root cause? Section 2: Overview of failure mechanisms Section 3: Failure analysis techniques – Non-destructive analysis techniques – Destructive analysis – Materials characterization Section 4: Summary and closure...

Publisher: NASA Office Of Safety And Mission Assurance

The Inline X-Ray Component Counter: The Next Step in SMT Inventory Automation

Jan 22, 2023 | Neotel Technology

The inline X-ray component counter, Neo Counter X800, can receive materials from an automated guided vehicle (AGV) or manually loaded by a trolley. The materials are picked up by a robotic arm and sent to the counter for counting. After the counting process, the software records the results and automatically prints a label with the correct quantity. This label is then attached to the surface of the reel. A stacker stacks the materials before being unloaded by the AGV or trolley. This process ensures accurate counting, efficient labelling, and streamlined material handling, making it a convenient way of managing electronic component inventory....

Publisher: Neotel Technology Co., Ltd

Introducing Closed-loop Nitrogen Control To Solder Reflow

Jan 17, 2023 | David Heller

To achieve higher levels of consistency in PCB output, process engineers are able to maintain tighter controls and reduce process-related defects by using closed-loop process controls. At every stage of assembly, from screen printing through placement to reflow, closed-loop systems help control the variable factors that can have adverse effects on the process....

Publisher: Heller Industries Inc.

How Challenging Conventional Wisdom Can Optimize Solder Reflow

Jan 17, 2023 | Marc Peo

As a manufacturing technology, SMT has acquired a "heritage" of widely accepted assumptions about its processes. However, yesterday'spractices are continually confronted by the shifting paradigms of today's production line....

Publisher: Heller Industries Inc.

The User Benefits of a Supplier Partnership

Jan 17, 2023 | Bjorn Dahle, Marc Peo

EQUIPMENT SUPPLIERS HAVE BECOME A RESOURCE FOR PROCESS CONTROL EXPERTISE, EVEN IN THE REFLOW OPERATION....

Publisher: Heller Industries Inc.

Vacuum Fluxless Reflow Technology for Fine Pitch First Level Interconnect Bumping Applications

Jan 17, 2023 | Yue Deng, Xike Zhao, Liang He, David Wright, Hossein Madanipour, Bret Halbe, Jung Kyu, Fred Tarazi, Gang Duan, Dror Trifon, Rahul Manepalli, David Heller

Heterogeneous integration has become an important performance enabler as high-performance computing (HPC) demands continue to rise. The focus to enable heterogeneous integration scaling is to push interconnect density limit with increased bandwidth and improved power efficiency. Many different advanced packaging architectures have been deployed to increase I/O wire / area density for higher data bandwidth requirements, and to enable more effective die disaggregation. Embedded Multi-die Interconnect Bridge (EMIB) technology is an advanced, cost-effective approach to in-package high density interconnect of heterogeneous chips, providing high density I/O, and controlled electrical interconnect paths between multiple dice in a package. In emerging architectures, it is required to scale down the EMIB die bump pitch in order to further increase the die-to-die (D2D) communication bandwidth. Aa a result, bump pitch scaling poses significant challenges in the plated solder bump reflow process, e.g., bump height / coplanarity control, solder wicking control, and bump void control. It's crucial to ensure a high-quality solder bump reflow process to meet the final product reliability requirements. In this paper, a combined formic acid based fluxless and vacuum assisted reflow process is developed for fine pitch plated solder bumping application. A high-volume production (HVM) ready tool has been developed for this process....

Publisher: Heller Industries Inc.

Flux Management

Jan 17, 2023 | Heller Industries

This paper describes the new flux management systems that Heller Industries introduced in 1999....

Publisher: Heller Industries Inc.

Function and Operational Theory of Condenser Tube Flux Collection System

Jan 17, 2023 | Heller Industries

Heller's new Condenser Tube Flux Recovery System is designed to provide more efficient flux collection than earlier Heller flux collection systems; while providing minimal down time for inspection and cleaning. The entire system easily fits within the rear of the top shell of an 1800-EXL oven. The system utilizes a different set of top shell caps specially designed to provide the best serviceability of both the flux collection system and maintenance of the heater zone blower motors....

Publisher: Heller Industries Inc.

Repeatability of the Temperature Profile under Load Variation

Jan 17, 2023 | Prepared by: John Poling

Repeatability of the Temperature Profile under Load Variation...

Publisher: Heller Industries Inc.

Are You Ready for Lead Free

Jan 17, 2023 | Marc Peo & Don DeAngelo

Various international market trends drive electronics manufacturers and their mate- rials and equipment suppliers to develop new assembly techniques to reduce the industry's environmental impact. Two pri- mary forces in this drive are the movements to lead-free assembly and ISO 14000 cer- tification. In response to these factors, reflow technology advances are enabling manufacturers to meet or anticipate the new environmental mandates....

Publisher: Heller Industries Inc.

The Greening of the Reflow Process

Jan 17, 2023 | Atsushi Kikuchi

After years of concentration on resolving productivity- related concerns such as increasing speed, consistency and throughput while reducing costs, many of the world's leading electronics manufacturers have added a new mandate to their agendas. They are seeking to minimize the environmental impacts of their assembly processes and final products without sacrificing the high levels of productivity and quality that have been achieved through decades of effort....

Publisher: Heller Industries Inc.

Let's Get the Lead Out

Jan 17, 2023 | Marc Peo

Let's Get the Lead Out...

Publisher: Heller Industries Inc.

A Practical Investigation into the Use of No Lead Solders for SMT Reflow

Jan 17, 2023 | Heller Industries and Soldering Technology David Heller and Jim Raby

A Practical Investigation into the Use of No Lead Solders for SMT Reflow...

Publisher: Heller Industries Inc.

Effect of Reflow Profile on SnPb and SnAgCu Solder Joint Shear Force

Jan 17, 2023 | Jianbiao Pan , Brian J. Toleno , Tzu-Chien Chou , Wesley J. Dee

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The degree of wetting, the microstructure (in particular the intermetallic layer), and the inherent strength of the solder all factor into the reliability of the solder joint. This paper presents experimental results on the effect of reflow profile on both 63%Sn 37%Pb (SnPb) and 96.5%Sn 3.0%Ag 0.5%Cu (SAC 305) solder joint shear force. Specifically, the effect of the reflow peak temperature and time above solder liquidus temperature are studied. Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb have been developed with three levels of peak temperature (230 o C, 240 o C, and 250 o C for SAC 305; and 195 o C, 205 o C, and 215 o C for SnPb) and three levels of time above solder liquidus temperature (30 sec., 60 sec., and 90 sec.). The shear force data of four different sizes of chip resistors (1206, 0805, 0603, and 0402) are compared across the different profiles. The shear force of the resistors is measured at time 0 (right after assembly). The fracture surfaces have been studied using a scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS)...

Publisher: Heller Industries Inc.

Reflow Techniques for Void Reduction

Jan 17, 2023 | David Heller

BTC Void Reduction For Yield and Performance Enhancement...

Publisher: Heller Industries Inc.

THE LAST WILL AND TESTAMENT OF THE BGA VOID

Jan 17, 2023 | David Hillman, Dave Adams, Tim Pearson, Brad Williams, Brittany Petrick, and Ross Wilcoxon Rockwell Collins. David Bernard, Ph.D., John Travis, Evstatin Krastev, Ph.D., and Vineeth Bastin Nordson DAGE

The impact of voiding on the solder joint integrity of ball grid arrays (BGAs)/chip scale packages (CSPs) can be a topic of lengthy and energetic discussion. Detailed industry investigations have shown that voids have little effect on solder joint integrity unless they fall into specific location/geometry configurations. These investigations have focused on thermal cycle testing at 0°C-100°C, which is typically used to evaluate commercial electronic products. This paper documents an investigation to determine the impact of voids in BGA and CSP components using thermal cycle testing (-55°C to +125°C) in accordance with the IPC- 9701 specification for tin/lead solder alloys. This temperature range is more typical of military and other high performance product use environments. A proposed BGA void requirement revision for the IPC-JSTD-001 specification will be extracted from the results analysis....

Publisher: Heller Industries Inc.

THE EFFECT OF VACUUM REFLOW PROCESSING ON SOLDER JOINT VOIDING AND THERMAL FATIGUE RELIABILITY

Jan 17, 2023 | Richard Coyle, Dave Hillman, Michael Barnes, David Heller, Charmaine Johnson, Richard Popowich, Richard Parker, Keith Howell, Joerg Trodler, Adam Murling

A test program was developed to evaluate the effectiveness of vacuum reflow processing on solder joint voiding and subsequent thermal cycling performance. Area array package test vehicles were assembled using conventional reflow processing and a solder paste that generated substantial void content in the solder joints. Half of the population of test vehicles then were re-processed (reflowed) using vacuum reflow. Transmission x-ray inspection showed a significant reduction in solder voiding after vacuum processing. The solder attachment reliability of the conventional and vacuum reflowed test vehicles was characterized and compared using two different accelerated thermal cycling profiles. The thermal cycling results are discussed in terms of the general impact of voiding on solder thermal fatigue reliability, results from the open literature, and the evolving industry standards for solder voiding. Recommendations are made for further work based on other void reduction methods and additional reliability studies....

Publisher: Heller Industries Inc.

Optimizing Reflowed Solder TIM (sTIMs) Processes for Emerging Heterogeneous Integrated Packages

Jan 17, 2023 | 2022 IEEE 72nd Electronic Components and Technology Conference (ECTC)

Reflowed indium metal has for decades been the standard for solder thermal interface materials (solder TIMs or sTIMs) in most high-performance computing (HPC) TIM1 applications. The IEEE Heterogeneous Integration Thermal roadmap states that new thermal interface materials solutions must provide a path to the successful application of increased total-package die areas up to 100cm2. While GPU architectures are relatively isothermal during usage, CPU hotspots in complex heterogeneously-integrated modules will need to be able to handle heat flux hotspots up to 1000W/cm2 within the next two years. Indium and its alloys are used as reflowed solder thermal interface materials in both CPU and GPU "die to lid/heat spreader" (TIM1) applications. Their high bulk thermal conductivity and proven long-term reliability suit them well for extreme thermomechanical stresses. Voiding is the most important failure mode and has been studied by x-ray. The effects of surface pretreatment, pressure during reflow, solder flux type/fluxless processing, and preform design parameters, such as alloy type, are also examined. The paper includes data on both vacuum and pressure (autoclave) reflow of sTIMs, which is becoming necessary to meet upcoming requirements for ultralow voiding in some instances....

Publisher: Heller Industries Inc.

New Laser-Based PCB Depaneling Method from Coherent Increases Process Utilization

Jan 16, 2023 | Coherent, Inc.

Technological changes in the materials, thickness, and composition of PCBs are motivating a move away from traditional mechanical cutting and depaneling methods towards laser-based processes. But not all lasers for PCB depaneling are created equal. There are significant differences amongst various lasers in cut characteristics and quality, specifically in terms of heat affected zone (HAZ). This, in turn, affects process utilization since it determines how closely circuits can be placed on a PCB, and can also impact circuit functionality and downstream processes like waterproofing or EMI shielding. This document presents a new nanosecond laser and associated cutting process developed at Coherent Inc. which enables laser PCB depaneling with substantially reduced HAZ compared to other currently available products.

Publisher: Coherent, Inc.

LaserFactory: A Laser Cutter-based Electromechanical Assembly and Fabrication Platform to Make Functional Devices & Robots

Jan 16, 2023 | Martin Nisser, Christina Liao, YuChen Chai et al

LaserFactory is an integrated fabrication process that augments a commercially available fabrication machine to support the manufacture of fully functioning devices without human intervention. In addition to creating 2D and 3D mechanical structures, LaserFactory creates conductive circuit traces with arbitrary geometries, picks-and-places electronic and electromechanical components, and solders them in place. To enable this functionality, we make four contributions. First, we build a hardware add-on to the laser cutter head that can deposit silver circuit traces and assemble components. Second, we develop a new method to cure dispensed silver using a CO2 laser. Third, we build a motion-based signaling method that allows our system to be readily integrated with commercial laser cutters. Finally, we provide a design and visualization tool for making functional devices with LaserFactory. Having described the LaserFactory system, we demonstrate how it is used to fabricate devices such as a fully functioning quadcopter and a sensor-equipped wristband. Our evaluation shows that LaserFactory can assemble a variety of differently sized components (up to 65g), that these can be connected by narrow traces (down to 0.75mm) that become highly conductive after laser soldering (3.2Ω/m), and that our accelerationbased sensing scheme works reliably (to 99.5% accuracy).

Publisher: Massachusetts Institute of Technology

Advanced Laser Microfabrication in High Volume Manufacturing

Jan 16, 2023 | John Bickley

There is increased interest in the laser microfabrication of variable shape and size features for a wide variety of materials. Quality and throughput requirements continue to increase, with tighter tolerances regarding dimensional and positional specifications. Consequently, improved laser sources and manufacturing techniques, with advanced system integration and process control need to be developed to be able to address ever increasing industry requirements.

This paper discusses recent advances enabled by a new generation of IPG Photonics fiber lasers that are resulting in systems having greater flexibility, greater reliability and lower operating cost of ownership than their predecessors, and that are producing machining processing rates up to an order of magnitude faster. Examples are given of using high brightness, high pulse energy, pulsed fiber lasers known as quasi continuous wave (QCW) fiber lasers operating in the near infra red (1070 nm) with pulse durations in the micro to millisecond regime, as well as using green (532 nm) fiber lasers in the nanosecond regime. Applications include high speed drilling of ceramics such as alumina and AlN with sub-50um diameter holes machined at 3000, 750 and 300 holes per second in 100, 381 and 635 microns thick substrates, respectively; high speed cutting and scribing of alumina in 381 and 635 microns substrates, high quality cutting of up to 3 mm thick sapphire substrates, as well as high quality cutting & drilling of polymers from PEEK, to silicone, epoxy, and FR4 are presented. Laser machining techniques and their implementation in a new high-volume manufacturing platform are discussed.

Publisher: IPG Photonics World Headquarters

High Phosphorus ENIG – highest resistance against corrosive environment

Jan 10, 2023 | Sven Lamprecht and Petra Backus

Over the past years there has been consistent growth in the use of electroless nickel / immersion gold (ENIG) as a final finish. The finish is now frequently being used for PBGA, CSP, QFP and COB and more recently gathered considerable interest as a low cost under-bump metallization for flip chip bumping application. One of the largest users for this finish has been the telecommunication industry, were millions of square meters of PCBs with ENIG have been successfully used. The nickel layer offers advantages such as multiple soldering cycles and hand reworks without copper dissolution being a factor. The nickel also acts as a reinforcement to improve through-hole and blind micro via thermal integrity. In addition the nickel layer offers advantages such as co-planarity, Al-wire bondability and the use as contact surface for keypads or contact switching. Especially those pads, which are not covered by solder need a protective coating in corrosive environment – such as high humidity or pollutant gas....

Publisher: Atotech

Eliminating Ni Corrosion in ENIG/ENEPIG Using Reduction-Assisted Immersion Gold in Place of Standard Immersion Gold

Jan 10, 2023 | George Milad, Jon Bengston and Albin Gruenwald

Nickel corrosion in ENIG and ENEPIG is occasionally reported; when encountered at assembly it manifests as soldering failures in ENIG and wire bond lifts in ENEPIG. Although not common, it can be highly disruptive, resulting in missed deliver schedules, supply chain disruption, failure analysis investigations, and liability - all very costly....

Publisher: Uyemura International Corporation

EFFECTS OF ENIG NICKEL CORROSION ON WETTING BALANCE TEST RESULTS AND INTERMETALLIC FORMATION

Jan 10, 2023 | Donald Gudeczauskas, George Milad

Since the IPC-4552 rev A for ENIG was introduced there have been many requests for clarification of acceptable and unacceptable levels of nickel corrosion. This paper attempts to further clarify the effects of nickel corrosion on solder wetting balance test results and the resultant intermetallic formed. The study will attempt to produce level 1, level 2, and level 3 corrosion as denoted by IPC-4552 rev A and tabulate wetting balance results and congruity of intermetallic formed....

Publisher: Uyemura International Corporation

BLACKPAD REVISITED

Jan 09, 2023 | M. Simard-Normandin, C. Banks

Since the implementation of lead-free soldering, solderability issues appear to have become more common. The higher soldering temperature releases volatiles creating solder voids. The higher temperature also increases board and component flexing. Surface mount components fall off boards and BGA (Ball Grid Array) balls crack cleanly at the intermetallic interface creating open circuits. Black pad is often found as the root cause of these issues. However, black pad is a catch-all expression used to describe a variety of problems. As common as it is, black pad is not always recognised. What does it look like? How can one differentiate black pad from other soldering defects? We present high resolution optical and SEM (Scanning Electron Microscopy) images of real-life soldering problems, demonstrating the difference between black pad issues, flexing issues and component issues, pointing at specific features identifying the syndrome.

Publisher: MuAnalysis

PCB/Substrate Finishing Overview

Jan 06, 2023 | John Swanson

PCB/Substrate Finishing Overview - iNEMI - PCB Surface Finish Overview. Surface Finish deployment ranked by surface area. OSP greatest. Imm Tin. ENIG. Silver. ENEPIG....

Publisher: MacDermid, Inc.

ACHIEVING A SUCCESSFUL ENIG FINISHED PCB UNDER REVISION A OF IPC 4552 MACDERMID ENTHONE

Jan 06, 2023 | Martin Bunce, Lenora Clark, John Swanson

The 4-14 IPC Standards Committee recently created a revision to the IPC4552 specification for Electroless Nickel/Immersion Gold (ENIG) finished Printed Circuit Boards (PCB). Revision A brings a more comprehensive evaluation of metal layer thicknesses measurement, composition and introduces, for the first time, a quality aspect for nickel corrosion which has been historically connected to a defect called black line nickel or black pad....

Publisher: MacDermid, Inc.

Hidden Head-In-Pillow soldering failures

Dec 23, 2022 | Bart Vandevelde , Geert Willems , Bart Allaert

One of the upcoming reliability issues which is related to the lead-free solder introduction, are the headin-pillow solderability problems, mainly for BGA packages. These problems are due to excessive package warpage at reflow temperature. Both convex and concave warpage at reflow temperature can lead to the head-in-pillow problem where the solder paste and solder ball are in mechanical contact but not forming one uniform joint. With the thermo-Moiré profile measurements, this paper explains for two flex BGA packages the head-in-pillow. Both local and global height differences higher than 100 µm have been measured at solder reflow temperature. This can be sufficient to have no contact between the molten solder ball and solder paste. Finally, the impact of package drying is measured...

Publisher: IMEC

Characterize and Understand Functional Performance Of Cleaning QFN Packages on PCB Assemblies

Dec 19, 2022 | Mike Bixenman (Team Leader), KYZEN Corporation; Eric Camden, Foresite; Johnny CH Chen, Wistron; Qin Chen, Suzhou Eunow Company; Janet Cross, U.S. Army; Jeff Kautzer, GE Medical; Jason Keeping, Celestica; Milos Lazic, Indium Corporation; David Lober, KYZEN

Material and Process Characterization studies can be used to quantify the harmful effects that might arise from solder flux and other process residues left on external surfaces after soldering. Residues present on an electronic assembly can cause unwanted electrochemical reactions leading to intermittent performance and total failure. Components with terminations that extend underneath the package can trap flux residue. These bottom terminated components are flush with the bottom of the device and can have small solderable terminations located along the perimeter sides of the package. The clearance between power and ground render high electrical forces, which can propagate electrochemical interactions when exposed to atmospheric moisture (harsh environments). The purpose of this research is to predict and understand the functional performance of residues present under single row QFN component packages. The objective of the research study is to develop and collect a set of guidelines for understanding the relationship between ionic contamination and electrical performance of a BTC component when exposed to atmospheric moisture and the trade-offs between electrical, ionic contamination levels, and cleanliness. Utilizing the knowledge gained from undertaking the testing of QFN components and associated DOE, the team will establish a reference Test Suite and Test Spec for cleanliness....

Publisher: iNEMI (International Electronics Manufacturing Initiative)

Approach to detecting latent defects of the printed circuit boards thin-filmed coatings

Dec 05, 2022 | Alexey Balastov, Boris Kovrigin, and Valery Lavrinovich

One of the main reasons for the space vehicles (SV) power supply systems failure is a secondary arc. In the statistics of fatal failures that can lead to the SV loss, the failure rate of the power supply systems is 9%, but despite this, there are no standard methods for diagnosing the onboard equipment for the arc stability, due to the relative novelty of the problem. The problem we encountered is associated with the need to switch power supply systems to the voltage levels that are much higher than the arc voltage in the space vacuum. From the point of view of the defects downing that can lead to arcing, the most vulnerable are the insulation coatings.Therefore, a significant part of the problem solution is concentrated in the development of the specific methods for these coatings diagnostics. In space technology, such diagnostics significance is increased due to the inability to provide necessary repairs or services in the outer space....

Publisher: Tomsk State University

Latent heat induced deformation of PCB substrate: Measurement and simulation

Dec 05, 2022 | Denis Froˇs *, Petr Veselý, Jan Zemen, Karel Duˇsek

The work evaluates the impact of latent heat (LH) absorbed or released by a solder alloy during melting or solidification, respectively, on changes of dimensions of materials surrounding of the solder alloy. Our sample comprises a small printed circuit board (PCB) with a blind via filled with lead-free alloy SAC305. Differential scanning calorimetry (DSC) was employed to obtain the amount of LH per mass and a thermomechanical analyzer was used to measure the thermally induced deformation. A plateau during melting and a peak during solidification were detected during the course of dimension change. The peak height reached 1.6 μm in the place of the heat source and 0.3 μm in the distance of 3 mm from the source. The data measured during solidification was compared to a numerical model based on the finite element method. An excellent quantitative agreement was observed which confirms that the transient expansion of PCB during cooling can be explained by the release of LH from the solder alloy during solidification. Our results have important implications for the design of PCB assemblies where the contribution of recalescence to thermal stress can lead to solder joint failure....

Publisher: Czech Technical University in Prague

No-fault-found and intermittent failures in electronic products

Dec 05, 2022 | Haiyu Qi , Sanka Ganesan, Michael Pecht

This paper reviews the possible causes and effects for no-fault-found observations and intermittent fail- ures in electronic products and summarizes them into cause and effect diagrams. Several types of inter- mittent hardware failures of electronic assemblies are investigated, and their characteristics and mechanisms are explored. One solder joint intermittent failure case study is presented. The paper then discusses when no-fault-found observations should be considered as failures. Guidelines for assessment of intermittent failures are then provided in the discussion and conclusions....

Publisher: CALCE Center for Advanced Life Cycle Engineering

Windows Remote Arduino

Dec 01, 2022 | FS PCBA

PCB components or supplies that need to be prepared in advance Arduino Uno Rev3 The Arduino Uno is a rigid PCB microcontroller board based on the ATmega328P (datasheet). It has 14 digital input/output pins (6 of which can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header and a reset button. It includes everything needed to support the microcontroller; just connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery and you're ready to go. You can tinker with the Uno without worrying about doing something wrong, worst case you can replace the chips for a few bucks and start over. "Uno," which means "Uno" in Italian, was used to mark the release of Arduino software (IDE) 1.0. The Uno board and Arduino software (IDE) version 1.0 is the reference version of the Arduino and has now evolved to newer versions. The Uno board is the first in a series of USB Arduino boards and is the reference model for the Arduino platform; see the Arduino Board Index for an exhaustive list of current, past, or obsolete boards. Arduino Uno Rev3 SparkFun Bluetooth PCB Modem - BlueSMiRF Silver BlueSMiRF Silver is the latest Bluetooth PCB wireless serial cable replacement! This version of the popular BlueSMiRF uses the RN-42 module, which has a somewhat smaller range than the RN-41 module used in BlueSMiRF Gold. These modems are used as serial (RX/TX) pipes. Any serial stream from 2400 to 115200bps is seamlessly passed from your computer to your target. The remote unit can be powered from 3.3V to 6V for easy battery connection. All signal pins on the remote unit are 3V-6V tolerant. No level translation is required. Do not connect this device directly to a serial port. If you need to connect it to a computer, you will need an RS232 to TTL converter circuit. MCL053MD MCL053MD is a 5mm HE red circular LED PCB component with red diffuser lens, through hole mount, round lens, 15mcd luminous intensity, 625nm peak wavelength, 45° viewing angle. This LED light is made with GaAsP on GaP. 85mW power consumption -40 to +85°C operating temperature range Multicomp Pro products are rated 4.6 out of 5 stars 12 Month Limited Warranty *See terms and conditions for details 96% of customers would recommend to a friend 14N9416-40.jpg (320×193) Male/Male Jumper Wires Manufacturer: ADAFRUIT Manufacturer Part No: 758 Newark Part No.: 88W2570 Technical Datasheet: 758 Datasheet 88W2570-40.jpg (200×200) RCC120610K0FKEA MFG_RCC1206.jpg (640×640) The start of a Windows remote Arduino PCBA project Program the Arduino First, let's program the Arduino. Download and install the Arduino software from the official Arduino website. Connect your Arduino device to your computer using USB. Start the Arduino application. Verify you have the correct Arduino board selected under Tools > Boards Verify you have the correct COM port selected under Tools > Ports In the Arduino IDE, navigate to File > Examples > Firmata > StandardFirmata Confirm that StandardFirmata will use the correct baud rate for your connection. (see note on baud rates below) Press "Upload" to deploy the StandardFirmata sketch to the Arduino device. Baud Rate StandardFirmata communicates with Bluetooth devices using a serial line or via USB. By default it uses a baud rate of 57,600 bps. Depending on the configuration of your Bluetooth device, you may need to modify this rate. It can be found in the setup method and looks like this: Firmata.begin(57600); Change the value to the correct baud rate. For USB, this value is configurable in the device and Windows Remote Arduino connection parameters. If you are using a bluetooth PCBA, the baud rate depends on the device you are using. Hardware Set Up You can always start with a USB, WiFi or Ethernet connection, but let's cover the simple connection of a Bluetooth PCBA device and LED, we will use the Windows Remote Arduino library to turn the LED on and off via Bluetooth! Connect the power and ground rails on the rigid PCB to the 5V and GND pins on the Arduino respectively. Power connections are easily tracked using color-coded wires (red and black). power and ground rails Plug the Bluetooth device onto the rigid PCB and connect the VCC and GND pins to the power and ground rails on the rigid PCB respectively. Plug the Bluetooth device onto the rigid PCB Connect the TX-0 pin on the Bluetooth device to the RX pin on the Arduino. Likewise, connect the RX-1 pin on the Bluetooth device to the TX pin on the Arduino. The TX-0 pin is interconnected with the Arduino's RX pin. Note that the yellow wire in the picture goes from the Bluetooth device's transmit pin to the Arduino's receive pin, and the orange wire does the opposite. This step is critical to establishing serial communication between the Bluetooth device and the Arduino, allowing messages transmitted from one device to be received by the other. The yellow wire is connected to the bluetooth PCB Establish serial communication between Bluetooth device and Arduino Before making this connection, make sure your code is uploaded to the Arduino. The Arduino Uno uses the same serial (TX and RX) pins to flash the device, this prevents any code being uploaded to it while another device is connected to those serial pins. Add an LED to the rigid PCBA. Note that the longer (or bent) leg is the anode (positive) and the shorter leg is the cathode (negative). Add an LED to the rigid PCBA. Connect the cathode of the LED to the ground rail of the rigid PCB using a 330Ω resistor. A 330Ω resistor is striped orange, orange, brown, gold as shown. 330Ω resistor connected to rigid PCB Connect the anode of the LED to any digital I/O pin on the Arduino. We use pin 13 in our example. The anode of the LED is connected to the Arduino Your FS PCBA setup is now ready! It should look similar to the setup shown in the image below. FS PCBA FS PCBA Project Code Arduino sketching Install Arduio Firmata Library: Step 1.PNG (589×298) Step 2.PNG (838×373) Go to Sketch Menu/Include Libraries/Manage Libraries and search for "Firmata" and install the latest version of the library. Now open and upload the "StandardFirmata" example from File/Examples/Firmata/StandardFirmata. It is done on the Arduino side. Now we will see the application for Windows Universal Platform. Windows Universal Platform App Download the example repository here. If you'd rather create your own electronics PCB fabrication project, follow the project setup guide here. Now that we're all set, let's get into some code! Create your project I set up a project called FS PCBA RemoteBlinky following the steps in the setup guide. In the screenshot below, you'll see the code-behind file, MainPage.xaml.cs, which simply creates a Bluetooth connection object and passes it to the RemoteDevice class in the constructor. You'll see that I specified my device name in this example. You can also enumerate available devices by calling the static .listAvailableDevicesAsync() function on the BluetoothSerial (and USBSerial) class before constructing the object. project00.png (1012×657) Notes for USB flex PCBA: USBSerial has many options for specifying your device. In the constructor, you can provide the device's VID and PID, just the VID, or a DeviceInformation object (obtained from the listAvailableDevicesAsync function above). Likewise, BluetoothSerial allows you to provide a device ID (as a string), a device name (also a string), or a DeviceInformation object. You can get the VID and PID combination of a USB device by following these steps: Open Device Manager from Control Panel or by pressing the Windows + Pause keys together and selecting the Device Manager link on the left. Expand the Ports (COM and LPT) menu Right click on your Arduino device and select properties On the Details tab, select Hardware ID from the drop-down menu. You may see multiple entries in the Value box, but any entry will have a matching PID and VID. These entries have the format "USB\VID_****&PID_****", where **** is the numeric ID value. USBSerial usb = new USBSerial( "VID_2341", "PID_0043" ); Guaranteed to work only with the following hardware devices: vidpid.png (408×455) Next, I'll add a callback function to the RemoteDevice object's DeviceReady event. This function is automatically called when the Bluetooth Flex PCB device is connected and all necessary settings have been initialized. You'll notice that I haven't implemented anything in that function at this point. Finally, call .begin() on the connection object to tell it to connect. Flex USB PCBA code considerations: The parameters of the .begin() function don't matter for bluetooth flex PCBA, but you have to use the same baud rate on Arduino and UsbSerial object (first parameter). Also, the second parameter must be "SerialConfig.8N1". The rest of the example works exactly the same no matter which connection type you use. project01.png (1003×651) Jump to the MainPage.xaml file and create a few buttons that turn the LEDs on and off. You'll notice that I've added the button callback to the Click event and set the IsEnabled property to false, FS Tech will explain why below! project02.png (1017×366) I implemented three functions in this step. First, the OnDeviceReady function now enables the button on the UI thread! This ensures that the button is only enabled when the Bluetooth connection is ready, as this usually takes a few seconds to happen. I also set up .digitalWrite() calls in the button callbacks OnButton_Click and OffButton_Click project04.png (1141×730) Flex PCBA Build and Deploy! Once connected, your button will be enabled and you can turn the LED on and off at will! Here's a screenshot of this basic example running on Windows Phone 10. screenshot.png (480×854) I really hope you enjoy duplicating this project and using it as a baseline for an incredible new set of PCBA projects! You can quickly go from PCB to PCBA with PCB assembly to get it done in no time. https://www.fs-pcba.com/...

Publisher: FS Technology

Effect of Multiple Reflow Cycles on Intermetallic Compound Creation

Nov 29, 2022 | Václav Wirth, Karel Rendl, and František Steiner

This paper deals with the effect of the solder profile and multiple reflow cycles on intermetallic compound (IMC) creation. Soldered joints between PCB and 1206 size chip resistors were made from SAC 305 or SnBi solder alloy. Samples were reflowed one to six times with one of the two different soldering profiles for each soldering alloys. The thickness and composition of IMC layers were measured and observed with a scanning electron microscope. The growing of IMC layers thickness was observed. The results are presented depending on greater value of heating factor and number of reflow cycles. The shear forces for the components were measured and the fracture interfaces were inspected.

Publisher: University of West Bohemia

The Effect Of Vacuum Reflow Processing On Solder Joint Voiding And Thermal Fatigue Reliability

Nov 07, 2022 | Richard Coyle, Dave Hillman, Michael Barnes, David Heller, Charmaine Johnson, Richard Popowich, Richard Parker, Keith Howell, Joerg Trodler, Adam Murling

A test program was developed to evaluate the effectiveness of vacuum reflow processing on solder joint voiding and subsequent thermal cycling performance. Area array package test vehicles were assembled using conventional reflow processing and a solder paste that generated substantial void content in the solder joints. Half of the population of test vehicles then were re-processed (reflowed) using vacuum reflow. Transmission x-ray inspection showed a significant reduction in solder voiding after vacuum processing. The solder attachment reliability of the conventional and vacuum reflowed test vehicles was characterized and compared using two different accelerated thermal cycling profiles. The thermal cycling results are discussed in terms of the general impact of voiding on solder thermal fatigue reliability, results from the open literature, and the evolving industry standards for solder voiding. Recommendations are made for further work based on other void reduction methods and additional reliability studies....

Publisher: Nokia Bell Labs

Effect Of Vacuum Reflow On Solder Joint Voiding In Bumped Components

Oct 31, 2022 | Arvind Srinivasan Karthikeyan, Sa'd Hamasha, Michael Meilunas, and Fred Dimock

Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness. Due to the various advantages they offer, the use of Ball Grid Array packages is common across all industry sectors. They are also prone to process voiding issues. This study was performed to determine if vacuum assisted reflow process can help alleviate the voids in area array solder joints. Test parameters in this study largely focused on vacuum pressure level and vacuum dwell time....

Publisher: Auburn University

Lead-Free and Mixed Assembly Solder Joint Reliability Trends

Oct 31, 2022 | Jean-Paul Clech, Ph.D.

This paper presents a quantitative analysis of solder joint reliability data for lead-free Sn-Ag-Cu (SAC) and mixed assembly (SnPb + SAC) circuit boards based on an extensive, but non-exhaustive, collection of thermal cycling test results. The assembled database covers life test results under multiple test conditions and for a variety of components: conventional SMT (LCCCs, resistors), Ball Grid Arrays, Chip Scale Packages (CSPs), wafer-level CSPs, and flip-chip assemblies with and without underfill. First-order life correlations are developed for SAC assemblies under thermal cycling conditions. The results of this analysis are put in perspective with the correlation of life test results for SnPb control assemblies. Fatigue life correlations show different slopes for SAC versus SnPb assemblies, suggesting opposite reliability trends under low or high stress conditions. The paper also presents an analysis of the effect of Pb contamination and board finish on lead-free solder joint reliability. Last, test data are presented to compare the life of mixed solder assemblies to that of standard SnPb assemblies for a wide variety of area-array components. The trend analysis compares the life of area-array assemblies with: 1) SAC balls and SAC or SnPb paste; 2) SnPb balls assembled with SAC or SnPb paste....

Publisher: EPSI Inc.

Surfaces of mixed formulation solder alloys at melting

Oct 31, 2022 | M. J. Bozack, J. C. Suhling, Y. Zhang, Z. Cai, and P. Lall

Mixed formulation solder alloys refer to specific combinations of Sn-37Pb and SAC305 (96.5Sn–3.0Ag–0.5Cu). They present a solution for the interim period before Pb-free electronic assemblies are universally accepted. In this work, the surfaces of mixed formulation solder alloys have been studied by in situ and real-time Auger electron spectroscopy as a function of temperature as the alloys are raised above the melting point. With increasing temperature, there is a growing fraction of low-level, bulk contaminants that segregate to the alloy surfaces. In particular, the amount of surface C is nearly _50–60 at. % C at the melting point. The segregating impurities inhibit solderability by providing a blocking layer to reaction between the alloy and substrate. A similar phenomenon has been observed over a wide range of (SAC and non-SAC) alloys synthesized by a variety of techniques. That solder alloy surfaces at melting have a radically different composition from the bulk uncovers a key variable that helps to explain the wide variability in contact angles reported in previous studies of wetting and adhesion. VC 2011 American Vacuum Society. [DOI: 10.1116/1.3584821]...

Publisher: Auburn University

Microstructure and Intermetallic Formation in SnAgCu BGA Components Attached With SnPb Solder Under Isothermal Aging

Oct 31, 2022 | Anupam Choubey, Michael Osterman, and Michael Pecht

The global transition to lead-free (Pb-free) electronics has led component and equipment manufacturers to transform their tin–lead (SnPb) processes to Pb-free. At the same time, Pb-free legislation has granted exemptions for some products whose applications require high long-term reliability. However, due to a reduction in the availability of SnPb components, compatibility concerns can arise if Pb-free components have to be utilized in a SnPb assembly. This compatibility situation of attaching a Pb-free component in a SnPb assembly is generally termed "backward compatibility." This paper presents the results of microstructural analysis of mixed solder joints which are formed by attaching Pb-free solder balls (SnAgCu) of a ball-grid-array component using SnPb paste. The experiment evaluates the Pb phase coarsening in bulk solder microstructure and the study of intermetallic compounds formed at the interface between the solder and the copper pad....

Publisher: CALCE Center for Advanced Life Cycle Engineering

00338005-01 SMT Spare Parts Snap Switch Changer S 826B For Siemens Pick And Place Machine

Oct 31, 2022 | Germany

Model: IENENS PL EA Servo Motor Usage: Siemens Pick And Place Machine Description: Drive Module SERVO Wight: 2kg Packing: Paper Case Product Description: Motor High Light: 00338005-01 SMT Spare Parts, Snap Switch Changer SMT Spare Parts, SIEMENS Spare Parts Snap Switch Changer...

Publisher: Shenzhen Zhongrun Hi-Tech Technology Co., Ltd.

0032254403 A700 Vacuum Nozzle Type 418 SIEMENS AG Pip 418 Komplett Vectra

Oct 31, 2022 | Germany

Minimum Order Quantity: 1/pcs Price: Negotiable,EXW Price Packaging Details: High quality carton packaging Delivery Time: 1-2 work days Payment Terms: L/C, D/A, D/P, T/T, Western Union, MoneyGram Supply Ability: 1000pcs monthly, delivery time 1-2 days...

Publisher: Shenzhen Zhongrun Hi-Tech Technology Co., Ltd.

00341941S01 SMT Spare Parts Oben Stripping Device Plate 12*16mm Feeder

Oct 31, 2022 | Germany

Model: STRIPPING DEVICE PLATE Type: High-speed Chip Mounter Brand: SIEMENS SIPLACE ASM QUALITY: 100% Tested Usage: SIPLACE SMT Placement Machine HIGH LIGHT: Surface Mount Components, Smt Machine Part High Light: 00341941S01 SMT Spare Parts, 12*16mm SMT Spare Parts, 00341941S01...

Publisher: Shenzhen Zhongrun Hi-Tech Technology Co., Ltd.

00343010-01 SMT Spare Parts SIEMENS PL EA MCH Filter G1/2 Modulair 112

Oct 31, 2022 | Germany

Type: Filter Cup Model: Siemens Placement Machine Certification: CE，ROHS Trademark: Siemens Brief Description: Feeder Fixing Screws Wight: 1kg High Light: 00343010-01 SMT Spare Parts, ROHS SMT Spare Parts, SIEMENS PL EA MCH Filter...

Publisher: Shenzhen Zhongrun Hi-Tech Technology Co., Ltd.

00344065-03 KST-75-UP Siemens PCB Camera ALLIED Vision Technologies GmbH M60S

Oct 31, 2022 | Germany

Product Name: ALLIED Vision Technologies GmbH M60S Processing Customization: No Quality: 100% Tested Automatic Manual: Automatic Brand: Siemens AG Custom Processing: Yes High Light: 00344065-03, 00344065-03 Siemens PCB Camera, KST-75-UP Siemens PCB Camera...

Publisher: Shenzhen Zhongrun Hi-Tech Technology Co., Ltd.