Electronics Manufacturing Technical Articles

Feb 28, 2013

Keith Sweatman, Tetsuro Nishimura, Stuart D. McDonald, Kazuhiro Nogita

While it has long been known that the Cu6Sn5 intermetallic that plays a critical role in the reliability of solder joints made with tin-containing alloys on copper substrates exists in two different crystal forms over the temperature range to which electronics circuitry is exposed during assembly and service, it has only recently been recognized that the change from one form to the other has implications for solder joint reliability. (..) In this paper the authors report a study of the effect of cooling rates on Cu6Sn5 crystals. Cooling rates from 200°C ranged from 10°C/minute to 100°C/minute and the effect of isothermal ageing at intermediate temperatures was also studied. The extent of the phase transformation after each regime was determined using synchrotron X-ray diffraction. The findings have important implications for the manufacture of solder joints and their in-service performance... First published in the 2012 IPC APEX EXPO technical conference proceedings.......

Feb 22, 2013

LPKF

Day to day, year over year, businesses are forced to make critical R.O.I.—related decisions that impact the future and the bottom line—some of them reactionary, some forecasted. For a growing number of electronics manufacturers, many of those decisions revolve around whether a function should be performed by an outside contractor or kept in-house. But for many companies in the RF/microwave industry, this decision is often concerned with continuing to employ an outside PCB fabricator for prototype PCBs, or to make a $10,000 to $100,000 investment in an inhouse, rapid PCB prototyping machine that may represent a key competitive advantage....

Feb 14, 2013

Christopher Cain

Boundary-scan (1149.1) technology was originally developed to provide a far easier method to perform digital DC testing to detect intra-IC interconnect assembly faults, such as solder shorts and opens. Today's advanced IC technology now includes high-speed differential interfaces that include AC or DC coupling components loaded on the printed circuit assembly. Simple stuck-at-high/low test methods are not sufficient to detect all assembly fault conditions, which includes shorts, opens and missing components. Improved diagnostics requires detailed circuit analysis, predictive assembly fault simulation and more complex testing to isolate and accurately detect all possible assembly faults... First published in the 2012 IPC APEX EXPO technical conference proceedings...

Feb 08, 2013

Richard Lathrop

Solder voiding is present in the majority solder joints and is generally accepted when the voids are small and the total void content is minimal. X-ray methods are the predominate method for solder void analysis but this method can be quite subjective for non grid array components due to the two dimensional aspects of X-ray images and software limitations. A novel method of making a copper "sandwich" to simulate under lead and under component environs during reflow has been developed and is discussed in detail. This method has enabled quantitative solder paste void analysis for lead free and specialty paste development and process refinement. Profile and paste storage effects on voiding are discussed. Additionally an optimal design and material selection from a solder void standpoint for a heat spreader on a BCC (Bumpered Chip Carrier) has been developed and is discussed....

Feb 07, 2013

John Meyer and Carlyn A. Smith, Ph.D.

Silicone contamination is known to have a negative impact on assembly processes such as soldering, adhesive bonding, coating, and wire bonding. In particular, silicone is known to cause de-wetting of materials from surfaces and can result in adhesive failures. There are many sources for silicone contamination with common sources being mold releases or lubricants on manufacturing tools, offgassing during cure of silicone paste adhesives, and residue from pressure sensitive tape. This effort addresses silicone contamination by quantifying adhesive effects under known silicone contaminations. The first step in this effort identified an FT-IR spectroscopic detection limit for surface silicone utilizing the area under the 1263 cm-1 (Si-CH3) absorbance peak as a function of concentration (µg/cm2). The next step was to pre-contaminate surfaces with known concentrations of silicone oil and assess the effects on surface wetting and adhesion. This information will be used to establish guidelines for silicone contamination in different manufacturing areas within Harris Corporation... First published in the 2012 IPC APEX EXPO technical conference proceedings....

Jan 31, 2013

Joe Thomas

There are three key industry trends that are driving the need for temperature-dependent warpage measurement: the trend toward finer-pitch devices, the emergence of lead-free processing, and changes in device form factors. Warpage measurement has become a key measurement for analysis; prevention and prediction of interconnect defects and has been employed in failure analysis labs and production sites worldwide. First published in the 2012 IPC APEX EXPO technical conference proceedings...

Jan 30, 2013

Pete Doyon, VP of Product Management

Many OEM’s require that individual wires and cables used in their products be clearly identified with a mark or label. For some, such as in the military and aerospace markets, wire and cable identification (or “wire ID”) is mandatory and the process is governed by stringent specifications, such as SAE AS50881 (formerly MIL5088L). For others, the decision to use wire ID is a voluntary one. This article will describe what type of information is typically identified on wire and cables, concepts for improved productivity, what types of systems are available and the pros and cons of each....

Jan 29, 2013

Pete Doyon, VP Product Management

Choosing a new wire Cutting and Stripping (C&S) machine can be like shopping for a new car. With so many choices, where does one start? A nice, little sports car might be fun to have, but how often will it just sit there because it can’t carry a car load of kids or some odd-sized goods from the local home improvement store? You just might be better off with a midsize SUV that does a pretty good job at doing everything you need it to do....

Jan 24, 2013

Roland Girouard

Being found in the search engines for a wide variety of terms directly related to my business would be my 1st priority......

Jan 24, 2013

Jasbir Bath, Manabu Itoh, Gordon Clark, Hajime Takahashi, Kyosuke Yokota, Kentaro Asai, Atsushi Irisawa, Kimiaki Mori, David Rund, Roberto Garcia

The electronics industry has mainly adopted the higher melting point Sn3Ag0.5Cu solder alloys for lead-free reflow soldering applications. For applications where temperature sensitive components and boards are used this has created a need to develop low melting point lead-free alloy solder pastes. Tin-bismuth and tin-bismuth-silver containing alloys were used to address the temperature issue with development done on Sn58Bi, Sn57.6Bi0.4Ag, Sn57Bi1Ag lead-free solder alloy pastes. Investigations included paste printing studies, reflow and wetting analysis on different substrates and board surface finishes and head-in-pillow paste performance in addition to paste-in-hole reflow tests. Voiding was also investigated on tin-bismuth and tin-bismuth-silver versus Sn3Ag0.5Cu soldered QFN/MLF/BTC components. Mechanical bond strength testing was also done comparing Sn58Bi, Sn37Pb and Sn3Ag0.5Cu soldered components. The results of the work are reported....