Root cause failure analysis of printed circuit board. Identifying root causes is the key to preventing similar occurrences in the future. Surface mount package removal application note colin martin sc quality, central reliability abstract this application note will provide guidelines for how to remove a surface mount smt package from a printed circuit board pcb without damaging the smt. While a normal solder joint is usually bright and shiny, a cold solder joint is an abnormally dull, nonreflective, rough surface on the solder joint. Vanden heuvel oot cause analysis rca is a process designed for use in investigating and categorizing the root causes of events with safety, health, environmental, quality, reliability and production impacts.
Pareto analysis figure 4 showed that volume defect is the most frequent type. Surface mount package removal application note rev. Small ceramic capacitor failures 3ddr is an instrumentation data recorder seven units were tested to failure in order to understand dominant failure modes root cause of failure was determined for all the failure mode for 4 out of the 7 was a small ceramic capacitor failure. Soldering considerations for surface mount packages. Second, every individual brings their own knowledge, and biases, to the problem solving process. Unclassified unlimited release unclassified unlimited release 3ddr. February 21, 2007 introduction failure analysis of bga devices can be both expensive and daunting. Root cause analysis is about digging beneath the surface of a problem. Kaoru ishikawa, a japanese quality pioneer, introduced a very visual fishbone diagram that helps a whole team focus on. The high number of io is also what makes the failure analysis task so complex.
Realitycharting was created, so there is no reference to it there. When using the cause mapping method, the word root in root cause analysis refers. Improve smt assembly yields using root cause analysis in stencil. It is used so we can correct or eliminate the cause, and prevent the problem from recurring. It is a focused threeday class, which provides students with the opportunity to learn and understand the processes, tools, and materials used in. For purposes of this guide, the following definition suffices. Brc026 issue 1 understanding root cause analysis released 62012 page 4 of 20 find different tools work better for different types situations, for example based on the size or complexity of the incident or the typesource of data. Yield boils down to those three areas cost, delivery, and reliability, and its a key element for efficient, profitable assembly. Root cause analysis rca is the formal search for an individual or group of interacting true causes of a problem. Yield boils down to those three areas cost, delivery, and reliability. How to prevent solder joint voiding and cold solder defects. Improve smt assembly yields using root cause analysis in stencil design. Lotequipment analysis which allows extracting a set of suspected equipment, and the waferchamber analysis which reduces the size of the suspected set to single equipment.
Root cause analysis tools and techniques quality digest. Achieving improved reliability with failure analysis bhanu sood. The soundness of the approach is verified on a real smt manufacturing line. Guidance for performing root cause analysis rca with pips. Pdf in this paper we show how hybrid control and modeling techniques can. In social and behavior change communication sbcc, a root cause analysis is used to examine why there is a difference between the desired state of a health or social issue vision and what is happening now current situation. Use the analysis process to identify contributing factors. Large visible cracks and the insidious micro crack are usually blamed on the soldering. Design and implement changes to eliminate the root causes the team determines how best to change processes and systems to reduce the likelihood of another similar event. It is customary to refer to the root cause in singular form, but one or several factors may in fact constitute the root causes of.
Whichever method of root cause analysis is used it. Head and pillow, failure mode, non wet, reflow soldering, oxidation, warpage, misplacement. Its a great teambuilder because the group buysin to the real problems as they surface during the process. Improve smt assembly yields using root cause analysis in stencil design greg smith fct assembly, inc. Improve smt assembly yields using root cause analysis in. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining. Defect minimization methods for a noclean smt process. Root cause analysis root cause analysis is an investigative tool used to understand why an incident has occurred. An analysis of smt solder paste printing defects in smt pcb production, solder paste printing is a critical step. Com april 20 root cause failure analysis of printed circuit board assemblies through analysis of product and. Dmaic methodology to solder paste printing process in printed. The documentation must identify why something went or may go wrong and what has been done to make sure it does not happen again.
Set theory for root cause determination in semiconductor. Rootcause analysis is often used in proactive management to identify the root cause of a problem, that is, the factor that was the main cause of that problem. Pdf modeling and control of smt manufacturing lines using. Analysis of factors that affect yield in smt assembly. Brainstorm possible causes from these first immediate causes. Improve smt assembly yields using root cause analysis in stencil design reduction of first pass defects in the smt assembly process minimizes cost, assembly time and improves reliability. However, instead of looking for a singular root cause, we shift your problemsolving paradigm to reveal a system of causes.
Root cause analysis to improve solder paste release. A technique used to identify the conditions that initiate the occurrence of an undesired activity or state. The trust has adopted the root cause analysis tool for the investigation of claims. It is generally agreed that the purpose of root cause analysis is to find. Simply ask why 5 times starting with the effect of the problem. Reduction of first pass defects in the smt assembly process. In summary, the 0805 and 1206 devices all passed at ict, the frequency of defects per board. The purpose of determining the root cause s is to fix the problem at its most basic source so it doesnt occur again, even in other products, as opposed to merely fixing a failure symptom. Root cause analysis is different from troubleshooting troubleshooting is generally employed to eliminate a symptom in a given product, or to identify a failed component in order to effect a repair. There are many different approaches, methods, and techniques for conducting root cause analysis in other fields and disciplines. How to conduct a root cause analysis the compass for sbc. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining a successful and profitable assembly process. Cracks in ceramic surface mount technology smt components limit assembly reliability and yields. Root causes of these challenges will be identified and practical stencil design recommendations will be made with the intent of eliminating defects and improving.
Electronics failure analysis fa nts electronics failure analysis capabilities can be utilized to improve yield, determine root cause of failure, extrapolate life expectancy and improve reliability, and increase performance on integrated circuits ics, printed circuit boards pcbs, and passive surface mount devices as well as materials and assemblies. Rca emphasises the critical exploration of underlying and contributory factors. Root cause analysis is an important part of the investigation process when there is an incident or hazardin your workplace. General motors technical problem solving group drives. Root cause analysis is dedicated to finding the fundamental reason why the problem occurred in the first place, to prevent future failures. It is customary to refer to the root cause in singular form, but one or several factors may in fact constitute the root cause s of the problem under study. Greeley, co abstract reduction of first pass defects in the smt assembly process minimizes cost, assembly time and improves reliability. Solder bridging issues during assembly solder paste, solder. Assess the risk associated with the identified failure modes, effects and causes, and prioritize issues for. Root cause analysis methods distribution statement a this material has been approved for public release and unlimited distribution. The term event is used to generically identify occurrences that. Failure mode and effects analysis fmea is a method designed to. These cracks manifest themselves as electrical defects.
Pdf diagnosis of electronic systems in smt technological line. Smt assembly boot camp course electronics assembly. Root cause analysis rca is a method that is used to address a problem or nonconformance, in order to get to the root cause of the problem. By reducing first pass defects, manufacturers save money and time, as well as improving their products reliability. Identify and fully understand potential failure modes and their causes, and the effects of failure on the system or end users, for a given product or process. Root cause analysis is often used in proactive management to identify the root cause of a problem, that is, the factor that was the main cause of that problem. Smt troubleshooting typical smt problems for additional process solutions, please refer to the. Does the size of the pwb smt land pad affect solder paste release. The electronics industry is trending toward environmentally friendly manufacturing, smaller and. When using the cause mapping method, the word root in root cause analysis refers to causes that are beneath the surface. Identify the root causes a thorough analysis of contributing factors leads to identification of the underlying process and system issues root causes of the event. An analysis of smt solder paste printing defects bittele. Whichever method of root cause analysis is used it is usually necessary to commence with.
Electronics failure analysis national technical systems. Freescale tm and the freescale logo are trademarks of freescale semiconductor, inc. Root cause the deepest underlying cause, or causes, of positive or negative symptoms. Ipls root cause analysis identified the two possible event scenarios large service large service large service ug 621 ug 631 ug 651 large service ug 661 south bay middlesouth bay middlenorth bay north bay ipls action plan addresses both possible event scenarios 26 s meridian street 480volt spot network vault 15. Delayed reflow across smt components tombstone components ball in socket area array component. Root cause failure analysis of printed circuit board assemblies through analysis of product and tooling design. Us government accountability office gao the process of problem solving used to identify the underlying or initiating source of a nonconformance. The trick is to use the right tool to identify the root cause of a problem and not just the symptoms of a problem. Configuration of a smt technological line with diagnosis equipment.
Improve smt assembly yields using root cause analysis. Free download root cause analysis template pdf editor software. If we are to properly evaluate the many socalled root cause analysis methods and tools, we need a standard to which they can be compared. Root cause analysis, yield improvement, smt defects, stencil, solder paste release, reflow. A summary of recommended design parameters is found in. The process of creating a root cause analysis report is quite complex, but at first you need to start with the introduction, as this will allow you to understand what happened during the failure event, how that happened and, of course, what caused that particular issue with root cause analysis tools and effective root cause analysis methods. Since the solder paste is used to directly form the soldering joint, the quality of solder paste printing affects the performance and reliability of the surface mount assembly. American association of veterinary diagnosticians aavld. A root cause analysis is a process used to identify the primary source of a problem. What is a root cause the root cause is the most basic causal factor or factors that, if corrected or removed, will prevent the recurrence of the situation. The general form of a probabilistic network for an smt line is shown in figure 1. The root cause of this is unequal soldering forces. Kaoru ishikawa, a japanese quality pioneer, introduced a very visual fishbone diagram that helps a whole team focus on this and get rapidly to consensus.