Defect minimization methods for a noclean smt process. Pdf modeling and control of smt manufacturing lines using. 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. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining. Yield boils down to those three areas cost, delivery, and reliability, and its a key element for efficient, profitable assembly.
However, instead of looking for a singular root cause, we shift your problemsolving paradigm to reveal a system of causes. A technique used to identify the conditions that initiate the occurrence of an undesired activity or state. Dmaic methodology to solder paste printing process in printed. Use the analysis process to identify contributing factors. By reducing first pass defects, manufacturers save money and time, as well as improving their products reliability. Pareto analysis figure 4 showed that volume defect is the most frequent type. Root cause the deepest underlying cause, or causes, of positive or negative symptoms. Set theory for root cause determination in semiconductor. Second, every individual brings their own knowledge, and biases, to the problem solving process. Root cause analysis, yield improvement, smt defects, stencil, solder paste release, reflow. 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 rca is the formal search for an individual or group of interacting true causes of a problem. A summary of recommended design parameters is found in. There are many different approaches, methods, and techniques for conducting root cause analysis in other fields and disciplines.
Identifying root causes is the key to preventing similar occurrences in the future. Analysis of factors that affect yield in smt assembly. Com april 20 root cause failure analysis of printed circuit board assemblies through analysis of product and. 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.
In summary, the 0805 and 1206 devices all passed at ict, the frequency of defects per board. The trust has adopted the root cause analysis tool for the investigation of claims. Configuration of a smt technological line with diagnosis equipment. 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. Freescale tm and the freescale logo are trademarks of freescale semiconductor, inc. Root cause failure analysis of printed circuit board.
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. Rca emphasises the critical exploration of underlying and contributory factors. Improve smt assembly yields using root cause analysis in stencil design. For purposes of this guide, the following definition suffices. Large visible cracks and the insidious micro crack are usually blamed on the soldering. Root cause analysis tools and techniques quality digest. Free download root cause analysis template pdf editor software. 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. The term event is used to generically identify occurrences that. These cracks manifest themselves as electrical defects. An analysis of smt solder paste printing defects bittele. An analysis of smt solder paste printing defects in smt pcb production, solder paste printing is a critical step. The root cause of this is unequal soldering forces. The documentation must identify why something went or may go wrong and what has been done to make sure it does not happen again.
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. It is generally agreed that the purpose of root cause analysis is to find. How to conduct a root cause analysis the compass for sbc. 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. Root cause analysis root cause analysis is an investigative tool used to understand why an incident has occurred. Realitycharting was created, so there is no reference to it there. Cracks in ceramic surface mount technology smt components limit assembly reliability and yields. Electronics failure analysis national technical systems. Root cause analysis methods distribution statement a this material has been approved for public release and unlimited distribution. Does the size of the pwb smt land pad affect solder paste release. Delayed reflow across smt components tombstone components ball in socket area array component. 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.
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. Root cause analysis is an important part of the investigation process when there is an incident or hazardin your workplace. It is a focused threeday class, which provides students with the opportunity to learn and understand the processes, tools, and materials used in. When using the cause mapping method, the word root in root cause analysis refers. 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. Whichever method of root cause analysis is used it. 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. Kaoru ishikawa, a japanese quality pioneer, introduced a very visual fishbone diagram that helps a whole team focus on. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining a successful and profitable assembly process. Whichever method of root cause analysis is used it is usually necessary to commence with. 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. The high number of io is also what makes the failure analysis task so complex.
Soldering considerations for surface mount packages. Us government accountability office gao the process of problem solving used to identify the underlying or initiating source of a nonconformance. Pdf in this paper we show how hybrid control and modeling techniques can. Improve smt assembly yields using root cause analysis in stencil. Root cause analysis is about digging beneath the surface of a problem. The electronics industry is trending toward environmentally friendly manufacturing, smaller and. 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. 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.
Achieving improved reliability with failure analysis bhanu sood. Root cause failure analysis of printed circuit board assemblies through analysis of product and tooling design. Simply ask why 5 times starting with the effect of the problem. Surface mount package removal application note rev. 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. Root cause analysis to improve solder paste release. Solder bridging issues during assembly solder paste, solder.
The soundness of the approach is verified on a real smt manufacturing line. Improve smt assembly yields using root cause analysis in stencil design greg smith fct assembly, inc. Brainstorm possible causes from these first immediate causes. February 21, 2007 introduction failure analysis of bga devices can be both expensive and daunting. Root causes of these challenges will be identified and practical stencil design recommendations will be made with the intent of eliminating defects and improving. How to prevent solder joint voiding and cold solder defects. Malware root cause analysis in action how to use the compromise rca model during analysis you organize informationartifacts artifacts are discovered through analyzing the data objective is to identify. Assess the risk associated with the identified failure modes, effects and causes, and prioritize issues for. When using the cause mapping method, the word root in root cause analysis refers to causes that are beneath the surface. Analysis of root causes the preheat time is too long and too high, preventing the flux from activating. Greeley, co abstract reduction of first pass defects in the smt assembly process minimizes cost, assembly time and improves reliability. 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. 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.
Smt troubleshooting typical smt problems for additional process solutions, please refer to the. General motors technical problem solving group drives. 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. It is used so we can correct or eliminate the cause, and prevent the problem from recurring. 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. Pdf diagnosis of electronic systems in smt technological line. It can be used on its own or in conjunction with the fishbone diagram analysis in moving from the chosen root cause to the true root cause. Yield boils down to those three areas cost, delivery, and reliability.
Head and pillow, failure mode, non wet, reflow soldering, oxidation, warpage, misplacement. 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. Failure mode and effects analysis fmea is a method designed to. Unclassified unlimited release unclassified unlimited release 3ddr. The trick is to use the right tool to identify the root cause of a problem and not just the symptoms of a problem.
Its a great teambuilder because the group buysin to the real problems as they surface during the process. Smt assembly boot camp course electronics assembly. Root cause analysis is dedicated to finding the fundamental reason why the problem occurred in the first place, to prevent future failures. Reduction of first pass defects in the smt assembly process. American association of veterinary diagnosticians aavld. Improve smt assembly yields using root cause analysis. 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. Improve smt assembly yields using root cause analysis in. The general form of a probabilistic network for an smt line is shown in figure 1. 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.
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