As printed circuit board assembly (PCBA) becomes more complex,Automatic Optical Inspection (AOI) and Automatic Xray Inspection (AXI) systems are becoming more widely used in electronics manufacturing. AXI has good defect detection capabilities,but its TaKT time becomes a concern when compared to other machines (screen printer,pick-and-place,reflow,and wave soldering) on the SMT line. How can these two testing machines be used effectively to test production? This translates into: (1) how can we reduce AXI test time by supplementing it with AOI? And (2) how can we use the AOI and
AXI test results to improve the overall manufacturing process and thereby increase production yields? Some studies were reported in the past with only AXI1-3. We have been doing this project with AOI and AXI test data analysis to improve assembly test yields.
With the Flextronics Manufacturing System (FMS) approach,we focus on Lean Manufacturing. Lean is a manufacturing philosophy that recognizes WASTE as the primary driver of cycle time,and employs techniques to continually drive out
waste in the various processes. Waste elimination is the most effective means to achieve cycle time reduction. We develop new processes to deal with three types of waste: (1) Over process (2) Defect waste,& (3) Inventory accumulation. We used the key elements of Six Sigma DMAIC (Define,Measure,Analyze,Improve,& Control) and statistical tools for the project. In this study we first started with one customer’s product,which previously had 100% components covered with AOI and >95% covered by AXI. We studied AOI,AXI,ICT,and Functional Test data for six months,and reduced AXI test coverage for some non-critical components. As a result of the reduction of AXI coverage,we were able to reduce AXI test time from above 4 minutes to below 3 minutes. In the meantime we also focused on process issues and improvements using daily AOI
and AXI test results. Test and process engineers worked together on this project and used the AOI/AXI test results to adjust the machine settings for solder paste printing,pick and place,and wave soldering machines; solving the process and material issues and making very good progress. An example of one product: We reduced AXI test time by only testing BGA,Fine Pitch ICs,RNs,and some “Critical to Function” parts. Therefore AXI component and pin coverage changed from 98.4%,and 98.9% to 13.6%,50.1% respectively. AXI test time was reduced from 4.1 minutes to 2 minutes. Meanwhile,the yields of AOI (top),AOI (bottom),AXI,ICT,and FT increased from 98.9%,97.3%,88.4%,98.9%,and 100% to 99.6%,99.0%,96.2%,98.9%,and 100% respectively. The cost saving results will be discussed in the paper.

The hidden cost of optical inspection systems is often in the programming time. In this paper we discuss a new AOI programming and inspection paradigm reduces the need for human intervention and improves program stability and quality. This paradigm is based on the principles of adaptability of the human brain. Our understanding of these principles has helped to facilitate the development of easy-to- program automated optical inspection machines that need little human intervention and yet exhibit a consistently high level of performance over extended periods.

An important development in high reliability electronics is the convergence of circuit board and advanced packaging technologies. This combination enhances the best attributes of each technology to achieve higher performing devices. These emerging technologies drive the need for critical cleaning,which requires continued innovation to meet cleanliness requirements. Additionally,the move to Pb-free alloys creates new demands from a cleaning process perspective. To meet
the reliability standards for smaller,lighter,and highly dense electronic assemblies,cleaning process integration between mechanical and chemical driving forces require consideration. Research studies suggest that removal of flux residue from under die packaging technologies reduces voiding and improves reliability. The purpose of this research investigates new
mechanical impingement designs and reports the correlation of Pb-free flux removal efficacy using design of experiment testing.

boards in the in-line aqueous cleaning process. As lead-free circuit boards become more complex and component spacing
decreases,the effectiveness of direct blow-off drying is greatly diminished. Adding blower power or slowing process speed will improve drying performance,but increase operating cost,and may decrease throughput.
This paper describes a new approach to drying circuit board assemblies that significantly reduces the cost of ownership of an aqueous cleaning system. Drying performance is increased through a hybrid drying process that reduces energy input,exhaust requirements and sound levels. The combination of high temperature blow-off and convection brings the flexibility to tailor drying performance to fit the product’s drying requirements

To improve the design efficiency of a micro drill bit,a method on the basis of the combination of theoretical analysis,numerical simulation and experimental verifications is presented. As examples,the theoretical analyses of drill bit stress
and rigidity conditions are investigated with emphasis. To perform such analyses,the finite element analysis (FEA) is recommended. To examine the accuracy of the theoretical analysis result and the performance of designed micro drill bit,
experimental verification is conducted. Two design examples using the presented design method,namely one design of micro drill bit for flexible PCB (FP type) and the other for high Tg PCB (HT type) are discussed.

Society today relies on electronic devices that influence every aspect of our lives,such as communication,transportation,computing,home appliances,and recreation. The reliability of any electronic device depends on the design and quality of the printed circuit board (PCB) assembly. The origin of the PCB begins with a design concept followed by its verification for the desired output. The development of a manufacturing process subsequently occurs with the production of a small volume of prototype PCBs,and scale up to full production takes place once the manufacturing process is established. At each
manufacturing scale up,it is advisable to evaluate and verify the quality of PCBs to appropriate material and/or performance specifications. The first part of this paper describes how we use both types of specifications to perform investigations at first article unpopulated and populated PCBs with the intent of assisting our customer’s selection of a board manufacturing process,and possibly a board manufacturer. A similar methodology is applicable to raw components and geometrical design changes to characterize product process control and/or identify soldering issues. The second part of this paper covers some studies of solder connection reliability,such as Black Pad,and a developing methodology for analysis and control.

The continuous temperature resistance of electrically insulating materials can be judged by examining the effect of thermal stress loads on the electrical properties,such as moisture and insulating resistance,tracking resistance,etc.
Which effects on the electrical insulating properties of solder masks are to be expected,in particular under subsequent climatic stress? This paper will present and discuss the results of moisture and insulating resistance tests in different climates as well as further electrical properties from both continuous storage tests at 150°C for 2,000 hours and thermal cycling tests over 1,000 cycles,-40°C/+150°C. The load at the high cycle temperatures shall be compared with those from the continuous temperature storage tests. Furthermore,the theoretical base of this methodology shall be discussed.
In order to consider any potential "pre-damage" caused by the various surface finishes,tests have also been performed with a "preliminary stress load" comparable to that of the printed circuit board and electronic assembly. The influences of processing with various surface finishes such as Nickel/Gold finish (ENIG),chemical tin finish (CSN) and HAL (Hot-Air Levelling) on the thermal cycling resistance have also been examined. The paper shall go on to discuss investigations into the moisture and insulation resistance in different climates as well as the influence of the base material and layout as well as precleaning and solder mask thickness on the thermal cycling resistance.
In addition,comparisons shall be made between aqueous-alkaline and polyalcohol developable materials.

The European Union passed two directives in 2003 addressing the increasing amount of waste from electric and electronic equipment: (1) Directives 2002/96/ECi – Waste Electrical and Electronic Equipment (WEEE) and (2) Directive 2002/95/ECii – Restriction on the use of certain Hazardous Substances in electrical and electronic equipment (RoHS).
The RoHS Directive focuses on restricting the proliferation of six hazardous substances in any product which plugs into an electrical outlet or uses a battery. Member States shall ensure that,from 1 July 2006,new electrical and electronic equipment put on the market does not contain lead,mercury,cadmium,hexavalent chromium,polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE).iii The cost of not complying with the RoHS directive,or any environmental directive,is enormous. The value/cost ratio of proper
documentation is immeasurable.
There are several papers,articles,and other publications on how to make the product compliant or on the steps needed to set-up a compliance team. Companies will sell you their component compliance database; hold your hand through a consulting session on how to create the compliance team; talk to you about how to make the products in the company compliant. These are all
great first steps to meeting the directive. But what happens when a product is selected for market analysis,and is actually audited for the six banned substances?
This paper provides direction on documenting the product’s readiness to meet the RoHS directive as part of a self-declaration strategy.

Tetrabromobisphenol-A (TBBPA) is a commercial flame retardant used in rigid FR-4 printed wiring boards (PWB). It is the single largest volume brominated flame retardant in the world. In this application,the TBBPA is fully reacted into the epoxy resins that form the base material of the PWB. TBBPA’s leadership position in the rigid printed wiring board market is due to several factors,including reliable performance over time.
This paper will look at the benefits of TBBPA as a flame retardant in epoxy resin PWB. It will also address the current regulatory status of TBBPA and PWB recycle. An update on the status of the EU Risk Assessment on TBBPA and other industry assessments that compare TBBPA to alternative flame retardants for PWB will be included.

The IPC's Lead Free program addresses one of the 6 Hazardous Substances regulated by the RoHS directive. Certification to the QC 080000,the IECQ HSPM Specification,addresses the other 5 Hazardous Substances called out by RoHS thus addressing all 6 of the restricted substances. The synergy of applying both systems allows a company to accomplish total due diligence.
Directive 2002/95/EC of the European Parliament and of the Council was published on 27 January 2003. Restriction of the use of certain Hazardous Substances in electrical and electronic equipment (commonly known and referred
to as RoHS) went into effect July 1,2006. The RoHS directive was established by the European Union in order to reduce waste harmfulness,and restrict certain types of hazardous substances from being imported into the EU. The directive bans the following six substances,above the noted concentration levels,in electrical and electronic equipment:
Substance
Lead – Pb
Mercury – Hg
Cadmium – Cd
Hexavalent Chromium – Cr(VI)
Polybrominated biphenyls – PBB
Polybrominated diphenyl ethers - PBDE
In May 2006,the European Union published a guidance document intended to assist companies as they attempt to comply with the EU RoHS directive. Key issues addressed within the Guidance include the establishment of a Compliance
Assurance System (CAS) and establishment of the underlying principles that might be used to guide member states that make up the European Union in RoHS enforcement. Also addressed by the guidance document are the type of documentation that ‘producers’ (within the specific definition given in Article 3 of the Directive) might be advised to keep,the ways in which Member State enforcement authorities might use such documentation to check for RoHS compliance,the ways in which sample preparation,and analytical testing might be employed to avoid inconsistent enforcement decisions between Member
States.