一份非常好非常经典实用的SMT工艺.doc

Page 1 27 CONFIDENTIAL MES NMP SMD Process SpecificationCopyright Nokia Mobile Phones CONTENTS SHIPPING STORAGE and PRODUCTION ENVIRONMENT 2 1 1General shipping and storage conditions 2 1 2Storage and handling conditions for solder paste 3 1 3Storage and handling conditions for printed wiring boards PWBs 3 1 4Storage conditions for underfill epoxy materials 4 1 5Shelf life time for different component categories 5 1 5 1Expired material handling 5 1 5 2Moisture sensitivity levels 5 1 6Drying baking moisture sensitive devices 6 1 6 1Drying baking restrictions 6 1 7DRY STORAGE CONDITIONS 7 1 8PASTE SPECIFICATIONS 7 2 STENCIL PRINTING PROCESS SPECIFICATIONS 8 2 1Squeegee 8 2 2Stencil 8 2 3Support tables 9 2 4Printing process parameters stencil printing 10 2 5Print result validation 11 3 AUTOMATED OPTICAL INSPECTION AOI 12 3 1Location of the machine in the production line 12 3 2Utilization of inspection results 12 3 3Component and paste alarm limits 12 4 PLACEMENT PROCESS SPECIFICATIONS 13 4 1Nozzles 13 4 2Feeders 13 4 3NC Programs 13 4 4Part Data Vision processing 14 4 5Placement process management data compatibility table 14 5 Reflow soldering profile measurement 15 5 1Profile measurement equipment 15 5 2Reflow profile measurement method 15 6 Standard lead containing soldering process 16 6 1 1Recommended reflow oven settings 17 7 Lead free soldering process 18 7 1Reflow profile definition for Pb free process 18 7 2General Pb free reflow soldering profile specification 19 7 3Basic profile specification for standard calibration board in Pb free process 20 7 4Start up settings for Pb free process 21 7 5Reflow profile measurement on product PWBs 22 8 UnderfiLl process 24 8 1General 24 8 2Dispensing pattern for CSP components 26 9 MANUAL SOLDERING PROCESS AND WORKMANSHIP CRITERIA 27 10 Specifications for visual inspection error criteria faults classification and training material 27 11 Related Documents 27 Page 2 27 CONFIDENTIAL MES NMP SMD Process SpecificationCopyright Nokia Mobile Phones SHIPPING STORAGE AND PRODUCTION ENVIRONMENT Nokia Real Estate dry storage time should be included Dry storage specification Temperature25 5 C Humidity15 min if more than 50 of paste volume is refilled or after paste collection together outside squeegee area paste should be kneeded Page 8 27 CONFIDENTIAL MES NMP SMD Process SpecificationCopyright Nokia Mobile Phones 2 STENCIL PRINTING PROCESS SPECIFICATIONS 2 1 Squeegee PropertySpecification Squeegee blade material Ni or Titanium plated stainless steel with adequate stiffness for high speed printing Thickness 275 10 m Bare stainless steel not recommended Squeegee holder angle critical parameter 60 2 5 Squeegee width for DEK positive displacement pump type valve is recommended Automatic dispenser Asymtek M 600 or Cam alot 3700 Needle Gage 18 or 21 or long needle Preheat of PWB Underfill materials require 70 100 C PWB surface temperatures for better capillary flow and fill Temperature of PWB and underfill PWB 70 100 C Note Too high temperature might cause gelling Underfill 20 40 C Note If the temperature too high the viscosity inside syringe starts to rise too fast Post heat of PWB PWB temperature 70 100 C Note Post heat is not required if PWB goes directly to curing oven after dispensing process Flow rate 9 75mg sec depending on dispensing pattern Dispensing speed Max 25mm sec Fiducials Two fiducial marks from PWB need to be used Height sense At least one measurement need to be done to make sure that the needle is on right height Measurements need to be done from first and third blocks If the tooling is not straight enough the height sense needs to be done from all four blocks Needle height Typically 0 5mm from the PWB surface for 0 8mm pitch CSP s 0 5 mm bumps 0 3 mm from the PWB surface for 0 5 mm pitch CSP s 0 3 mm bumps Note If some 0402 or 0201 components are closer that 1 1mm from the CSP Page 25 27 CONFIDENTIAL MES NMP SMD Process SpecificationCopyright Nokia Mobile Phones component the needle height must be 0 7mm to clear the components Right fillIf underfill can be seen from all four sides MAD 52 54mg Note Variation between different PWB s causes variation to required amount of underfill Curing150 C 5min alternatively 165 C 3min Note Time is minimum time Must not be less otherwise insufficient cure PWB surface temperature must not exeed 165 C Acceptance criteriaMin Underfill epoxy should cover outermost solder balls Max Underfill epoxy is not allowed to flow through hole to opposite side of PWB If adjacent component is covered with underfill epoxy and it need rework assembly should be scraped Otherwise underfill epoxy can touch other components on small area if the gap between CSPs and PWB is totally filled Incomplete underfill is allowed to be reworked manually in well controlled work places if noticed before curing Adding underfill material after curing is denied Rejected Rejected if rework needed Page 26 27 CONFIDENTIAL MES NMP SMD Process SpecificationCopyright Nokia Mobile Phones 8 2 Dispensing pattern for CSP components From process cycle time point of view it is recommended to use L patterns To avoid voids the pattern needs to start and end 1 3mm from the corner picture 3 This way the risk of voids is little and the dispensing speed is as fast as possible Picture 3 L pattern for dispensing underfill 1 3 mm 1 3 mm Dispensing pattern Page 27 27 CONFIDENTIAL MES NMP SMD Process SpecificationCopyright Nokia Mobile Phones 9 MANUAL SOLDERING PROCESS AND WORKMANSHIP CRITERIA All rework issues are moved from SMD Process Specification to separate document MES00265 SMD Rework Specification for Manufacturing It can be found from Operation Global DocMan R4 Lotus Notes database Link to that below Notes Link 10 SPECIFICATIONS FOR VISUAL INSPECTION ERROR CRITERIA FAULTS CLASSIFICATION AND TRAINING MATERIAL Visual inspection criteria applied at NMP is defined in document MES00055 SMD Workmanship Standard This standard in mainly based on ANSI IPC A 610B class 2 telecommunications Same criteria are used also for assemblies manufactured by subcontractors Applicable international standard ANSI IPC A 610B class