Concentration Monitoring & Closed Loop Control – Phase 2

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Historically,the determination of the concentration of cleaning agent in high precision electronic cleaning baths has depended on any one of several possible measurable parameters. Refractive Index (RI) is by far the most common. RI methods are excellent tools for use in simple systems where a single solute dominates the signal. In these situations,it is possible to characterize and calibrate how that solute affects the signal. However,the introduction of flux residues during the wash bath lifetime complicates the bath chemistry/physics to such an extent that RI signals no longer provide the same insight.
The introduction of flux residue has an enormous influence on the Refractive Index. Alternative means of measuring cleaning agent are necessary if cleaning agent concentration is to be known throughout the life of the bath. With a means to accurately measure bath cleaning agent,closed loop automated process control on the cleaning bath is possible; automating this labor intensive step in the production of electronic boards. We have found that acoustic measurements of cleaning bath solution are relatively independent of pH,conductivity,and dissolved solids in some of the most flux loaded baths. Utilizing acoustic sensing technology,field data was gathered from two beta site locations assessing the accuracy of the technology in fresh as well as contaminated wash baths.

Author(s)
Umut Tosun,Axel Vargas,Bryan Kim
Resource Type
Technical Paper
Event
IPC APEX EXPO 2014

HCFC-225 Phaseout—What Now?

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On January 1,2015,nine months from APEX 2014,the production and use restrictions on HCFC-225 will be in effect throughout the United States. This phase out is encompassing in scope. This phase out will have significant technical,performance,and economic implications for the electronics industry. The regulatory situation remains fluid. A number of alternative solvents have been or are in the process of being developed. We discuss the options for assemblers and component manufacturers.

Author(s)
Ed Kanegsberg
Resource Type
Technical Paper
Event
IPC APEX EXPO 2014

An Alternative Solvent with Low Global Warming Potential

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In the past 20 yrs the solvent industry has gone through a great deal of change. In the early 1990s,CFC-113 and 1,1,1-trichloroethane were the workhorses of the industry. The Montreal Protocol to phase-out substances that deplete the Earth’s protective Ozone Layer was implemented in the mid 1990s to reduce chemicals with ozone depletion potential. After phase-out of the CFC solvents,the solvent industry fragmented to a variety of cleaning solutions. The electronics industry was a large user of CFC solvents and many of these applications changed to aqueous based cleaners. Some of the industries moved to chlorinated and brominated solvents such as trichloroethylene and n-propyl bromide. Other industries changed to no-clean fluxes. But those alternatives are now facing various problems: e.g. aqueous based cleaners use a lot of energy,require long drying times,use equipment that requires frequent maintenance,and require a large footprint; no-clean fluxes leave flux residues; and trichloroethylene and n-propyl bromide have toxicity issues. In response to these serious issues newer solvents and blends are being introduced in the marketplace.
In this pursuit the company developed a new low global warming potential fluorinated solvent for precision cleaning. This solvent has a mosaic of properties that make it a good solution in the solvent domain. It is non-flammable,has low toxicity,environmentally friendly,low surface tension,rapid drying,excellent solvency and a number of other favorable properties. In this paper we will review the properties and performance of the new solvent.

Author(s)
R. Basu,R. Hulse
Resource Type
Technical Paper
Event
IPC APEX EXPO 2014

Potential Global Warming Contribution from a Typical Electronics

Examination of historical data for a defunct electronics manufacturing plant in Ontario,Canada has allowed the
determination of the potential global warming contribution by the plant for the years 1971 to 1995,inclusive. The
biggest contributors were determined to be consumed electrical power produced by burning fossil fuels,natural gas
usage,employee travel to and from work and discharge of gaseous chlorofluorocarbons (CFCs),while they were
being used. The latter dwarfed all other contributors.

Author(s)
Bev Christian,Tracey Forrest
Resource Type
Technical Paper
Event
IPC APEX EXPO 2013

Qualification of Solder Beading and Tombstoning in Passive Devices using Designed Experiments

Solder beading and tombstoning are observed increasingly with chip components as their size decreases. This is
even more crucial in today’s packaging,due to the high ratio of passive components in comparison to active
components. The increasing number of passive components affects the Defects Per Million Opportunities (DPMO),
which inturn affects the overall yield of the assembly line. Hence,it is vital to understand the various causes within
the assembly process,which influence the occurrence of these defects. This paper will discuss the results of a
process characterization study to understand the effects of solder paste,stencil thickness,board support,reflow
profile and the component size on the formation of solder beads and tombstones. A Resolution-V DOE analysis was
performed to determine the effect of these factors on the defect occurrence. The response variable for the study was
% defects,the ratio of number of defect occurrences to the total number of available defect opportunities.

Author(s)
Vijaykumar Ganeshan,Karthik Thenalur,S. Manian Ramkumar
Resource Type
Technical Paper
Event
IPC APEX EXPO 2013

New High-Performance Organophosphorus Flame Retardant

A new non-halogen flame retardant has been developed and is useful for a variety of high performance applications. This
non-reactive phosphorus-based material satisfies fire safety needs for a broad range of resins including epoxy,polyolefin,and
polyamide. The combination of excellent flame retardant efficiency,high thermal stability and exceptional electrical
properties is unique to this organophosphorus flame retardant and makes it a breakthrough technology for high speed,high
frequency use in fast growing wireless and wired infrastructures. Resin performance data,including formulations with
synergists,are presented in this paper.

Author(s)
Kimberly M. White,Daniel De Schryver,Randy Chaya
Resource Type
Technical Paper
Event
IPC APEX EXPO 2013

Evaluating Corrosion Resistance of Ceramic Resistors: Mixed Flowing Gas versus Flower of Sulfur Tests

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Multi-layer organic laminates which make up over 90% of the present types of interconnecting substrates in today’s electronics can develop a loss of insulation resistance between two biased conductors due to a failure mechanism known as conductive filament formation. The probability of CFF is a function of temperature,moisture content,the voltage bias,manufacturing quality and processes,materials and other environmental conditions and physical factors. Filament formation typically appears to arise in two steps: a degradation of the resin/glass fiber bond followed by an electrochemical reaction. Bond degradation provides a path along which electro-deposition may occur due to electrochemical reaction. The path may result from poor glass treatment,from the hydrolysis of the silane glass finish and from mechanical stresses. Microscopic examinations of failure sites have shown that conductive filaments can be formed along de-bonded or delaminated fiber glass/epoxy resin interfaces,due to breaking of the silane bonds. The bi-functional silane molecules act as a link between the glass fiber and resin by forming a chemical bond with the glass surface through a siloxane bridge,whereas its organo-functional group bonds to the polymeric resin. The organosilane bonds are known to chemically degrade by hydrolysis. This paper will characterize the degradation of the interfacial bonds between the glass fibers and organic resin. Analytical technical techniques such as Nano-indentation are used to characterize the quality of the interface and follow the change in this interface as a function of absorbed moisture into the PCB.

Author(s)
Bhanu Sood,Michael Osterman
Resource Type
Slide Show
Event
IPC APEX EXPO 2013

Mobile Electronics,How to Protect Internal Circuitry from A Harsh Environment

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The portable electronics market has driven steep-slope growth for over a decade and continues to deliver amazing handheld electronic devices; manufacturers of these products are facing challenges they thought would be in the distant future: denser electronic substrates,more power demand and more heat to dissipate,stringent use conditions,and more importantly,demand for lower production cost.
Lowering production cost is critical to remaining competitive; hence the objectives become high “first pass quality” and low “returns for failed units.” There is high demand for manufacturing tools and processes that attain these goals.
Conformal coating is a cost effective process used to maintain the functionality of the electronic components inside a mobile device in harsh environmental conditions. This paper discusses recent developments in conformal coating that help enable the manufacturing process to meet the criteria for increased reliability at a lower cost,especially important for high production volume devices that command above average selling price.

Author(s)
Hector Pulido
Resource Type
Technical Paper
Event
IPC APEX EXPO 2013