DFM知识点培训教材课件

《DFM知识点培训教材课件》由会员分享，可在线阅读，更多相关《DFM知识点培训教材课件（68页珍藏版）》请在装配图网上搜索。

1、整 体 概 述THE FIRST PART OF THE OVERALL OVERVIEW,P L E A S E S U M M A R I Z E T H E C O N T E N T第一部分DFM 101Part 1DFM 101 Part1|Dec 2008 Celestica ConfidentialObjective:Provide basic training on performing manual DFMIncluded:Relevant guidelines from the DFx guidelines document Identify which checklist

2、 items can be evaluated using Valor Examples of DFM violations Some hands-on DFM exercisesNot included:DFT and DFA DFM using Valor Impact assessment of violationsDFM 101 OutlineDFM 101 Part1|Dec 2008 Celestica ConfidentialAfter the session,attendees should be able to:DFM 101 OutlinelManually identif

3、y DFM violations in a customers design,using the DFM checklist and the PCA DFx GuidelCreate a DFM report for the customer using the standard templateDFM 101 Part1|Dec 2008 ConfidentialDFM Review ProcessDFM 101 Part1|Dec 2008 Celestica Confidential No single“best”way to approach a DFM review,find you

4、r own preferred method through experience.One possible approach:start at a high level,and progressively“zoom in”Background information define context for the reviewHigh level design define basic manufacturing processDetailed design identify specific violations&general priorityImpact assessment quant

5、ify impact,in order of priorityInvestigate alternatives specific suggestions for changesDFM Review ProcessDFM 101 Part1|Dec 2008 Celestica ConfidentialBackgroundDefine context for the review Service level&product“context”:What is expected by the customer?e.g.turnaround time for the review,level of d

6、etail,etc.What type of product is it?e.g.low volume/high mix,high volume/low margin,high reliability,consumer,etc.What are the customers“hot buttons”?e.g.cost,quality,schedule,product functionality/performance,reliability,etc.Data review:what design information is available to include in the reviews

7、?History:what past information is available?e.g.production data,previous DFM reportsDFM Review ProcessDFM 101 Part1|Dec 2008 ConfidentialHigh Level Design Define basic manufacturing process Typically use BOM,assembly drawing&/or outer layers(lands)Look for parts/issues that may influence the basic p

8、rocess flow:PTH partsComplex connectorsTopside vs.backside Define a preliminary assembly process flow,to ensure that correct guidelines are applied during later detailed reviewPTH parts:selective wave,full wave,paste in hole,press fit,selective solder(softbeam,Ersa),etc.Test/inspect strategy Define

9、a preliminary panelization concept,to optimize Master Panel utilization&meet assembly panel requirementsDFM Review ProcessDFM 101 Part1|Dec 2008 Celestica ConfidentialDetailed Design Identify specific violations&general priority Use previous DFM reports,BOM,design file&/or gerber files,assembly draw

10、ing,PCB fabrication drawing,mechanical assembly drawing Work through Checklist,referring to DFM Guidelines as required Transfer items found to DFM Report,identify as hot/warm/cool focus designers limited time on the most critical itemsprioritize any additional detailed work required,e.g.impact asses

11、sment&alternativeskeep customers priorities in mind:cost,quality,schedule,etc.Request clarification or additional information from designer&/or suppliers if requiredDFM Review ProcessDFM 101 Part1|Dec 2008 ConfidentialImpact AssessmentQuantify impact,in order of priority Time consuming,not many tool

12、s available yet to assist with this Business office needs to support providing this feedback to the customer&incorporating it into product quoting/pricing Need an overall DFx business model in place:who pays for the service?who benefits from improvements implemented in the design?etc.Could provide f

13、or all items,or only on items that may not be fixedDFM Review ProcessDFM 101 Part1|Dec 2008 Celestica ConfidentialInvestigate AlternativesSpecific suggestions for changes Very time consuming,should only be performed if appropriate&as time permits Start with highest impact issues,or ones most likely

14、to have an alternative that we can suggestDFM Review ProcessDFM 101 Part1|Dec 2008 Celestica ConfidentialDFM ChecklistDFM 101 Part1|Dec 2008 Celestica Confidential Data&History Components Process Flow PTH Assembly SMT Assembly Layout&Spacing Land Patterns Silkscreen Board Outline PCB Fabrication Dra

15、wing Mechanical Assembly(not covered in this session)DFM Checklist TopicsDFM 101 Part1|Dec 2008 Celestica ConfidentialDFM ChecklistThe DFM Checklist is used to ensure that a comprehensive review is done,covering all important areasEach item on the DFM Checklist should be verified on the design being

16、 reviewed,either using Valor automated analysis or by manual checkingThe DFM Checklist is a tool to use during the review,it should NOT be included in the DFM Report given to the customerDFM 101 Part1|Dec 2008 ConfidentialHigher priority items are shown in bold text.If time is limited and a full rev

17、iew cannot be performed,the higher priority items should be covered first.Refer to the CLS DFx Guide for detailed guidelines.Items covered by Valor automated analysis will list the name of the check,e.g.c2toep.Items not covered by Valor are marked M and must be checked manually.Note:the priority of

18、a line item on the checklist does not necessarily correspond to a“hot/warm/cool”severity level of a particular issue(severity level depends on the specific issue found).DFM ChecklistDFM 101 Part1|Dec 2008 ConfidentialCheck off each item as it is reviewed,to ensure all items are covered during the re

19、view.Notes can be made during the review,to gather information for writing the DFM Report for the customer.The Checklist can be filled in softcopy or hardcopy(printed),whichever is more convenient.Issues found that are not covered in the DFM Checklist should also be noted and included in the DFM Rep

20、ort for the customer.DFM ChecklistDFM 101 Part1|Dec 2008 ConfidentialPutting an X in these boxes will automatically X the items covered by Valor analysis.DFM ChecklistDFM 101 Part1|Dec 2008 ConfidentialData&HistoryDFM 101 Part1|Dec 2008 ConfidentialData&HistoryDFM 101 Part1|Dec 2008 ConfidentialCAD

21、data(intelligent and appropriate for input to Valor)AVL BOM with RefDesAssembly drawings PCB fabrication drawing,including outline dimensions,hole sizes/tolerances,surface finishComponent drawings of complex or unique componentsCustom component informationDFx Guide:10.1 Data Package for DFMManual ch

22、eckData Adequate for DFM ReviewDFM 101 Part1|Dec 2008 ConfidentialThis will be covered in more details in the CLS Valor DFM training session.Data Adequate for DFM ReviewDFM 101 Part1|Dec 2008 ConfidentialIf any DFM reviews have previously been performed on the board,they should be reviewed again for

23、 the new design.If these still exist in the new design,they should be included in the new DFM report.Items that were not implemented previously may be candidates to address in the new design.Previous DFMDFM 101 Part1|Dec 2008 ConfidentialReview any existing production problems to determine if any ar

24、e design-related:Quality problems,major yield detractorsOperation time adders,e.g.manual operations,inefficient process flowSupply chain problems,ponent quality,single/sole source parts,delivery problemsEtc.Design-Related Production IssuesDFM 101 Part1|Dec 2008 ConfidentialRoHS=Restriction of Hazard

25、ous Substances A European Union Directive,effective from July 2006Bans 6 materials,including lead and certain brominated flame retardantsApplies to a broad range of electrical products-some exemptions applyCovers products both manufactured in or imported into EuropeSimilar legislation covering other

26、 regions being implemented or under developmentWhat is RoHS?RoHS/Pb-free ComplianceDFM 101 Part1|Dec 2008 ConfidentialComponents:Must not contain any of the 6 materials prohibited by RoHSMust meet requirements for high-yield Pb-free assembly,including:compatible surface finish,higher temperature res

27、istance with minimal warping,adequate MSL ratings at Pb-free reflow temperatures,adequate reliability after Pb-free assemblyAll components must be clearly identified as Pb-free,RoHS compliant,or RoHS exempt.If a component cannot be clearly identified,then it cannot be used in RoHS compliant products

28、.PCBs:Must not contain any of the 6 materials prohibited by RoHSMust be compatible with Pb-free assembly,including:compatible surface finish,higher temperature resistance with minimal warping,adequate reliability after Pb-free assemblyRoHS/Pb-free ComplianceDFM 101 Part1|Dec 2008 ConfidentialThe cus

29、tomer must clearly define the product requirements:RoHS compliant or not?Assemble with SnPb or Pb-free solder?The customer must verify that the BOM&PCB are compliant and compatible with the chosen assemblyMany components intended for Sn/Pb assembly are not Forward Compatible,i.e.able to be attached

30、to a PCB using Pb-free assembly.Not all components intended for Pb-free assembly are Backward Compatible,i.e.able to be attached to a PCB using SnPb assembly.For example:Pb-Free(SAC)BGAs are not drop-in compatible with standard SnPb assembly.They can produce satisfactory solder joints if the reflow

31、Tmax is greater than 227C,but this may cause other components on the board to be overheated.CLS Green Services can assist the customer by providing BOM analysis to verify compliance&compatibility RoHS/Pb-free ComplianceDFM 101 Part1|Dec 2008 ConfidentialComponentsDFM 101 Part1|Dec 2008 ConfidentialC

32、omponentsDFM 101 Part1|Dec 2008 ConfidentialExamples of new component packages:New advanced packages(BGAs,CSPs)New connectors New oddform parts,e.g.RF components Leadless componentsNew PackagesDFx Guide:N/AManual check DFM 101 Part1|Dec 2008 ConfidentialIn production at target site?In production at

33、another site?(3)Perform Process/Technology Transfer(1)(2)Create&Execute Development/Qualification Plan(2)(3)(4)Development/Qualification required?(3)YNYNOKYOKN(1)Consult documents CELQ-001-PROC-1293 Global Product Transfer Process for guidance(2)Consult document CELQ-001-SPEC-16 New Technology Devel

34、opment and Qualification for guidance(3)Contact Corporate Process Development for assistance(Thilo Sack&Alex Chen(Americas),None(Europe),Teng Hoon Ng&Daniel Tan(Asia)(4)Should be performed by the Manufacturing Engineer responsible for the product.Prior to starting execution,proposed Plan should be a

35、pproved by the appropriate Engineering Manager and by the Customer.Program Manager or Operations Manager should address how the work will be funded,and obtain Customer approval for any charges.New PackagesDFM 101 Part1|Dec 2008 ConfidentialProcess Development&Assembly Qualification considerations:Pr

36、ocess set-up&optimizationTooling(e.g.stencil design,placement nozzle/gripper,reflow nozzle)Process parameters(e.g.screening parameters,wave solder parameters,press fit force parameters,profiles for assembly and rework)Assembly reliabilityMechanical integrity of the interconnection between the compon

37、ent and the PCB(e.g.solder joints,press fit connection)is usually the focusNew PackagesDFM 101 Part1|Dec 2008 ConfidentialSources for land pattern design information:PCA DFx Guidelines document,Chapter 6 Component Library Creation(standard component package types)Other sites already using the same o

38、r similar part Component suppliers recommended land pattern,from spec sheet IPC land pattern calculator website http:/www.ipc.orgIPC-7351(replacement for IPC-SM-782)DFx Technical Forum database on Lotus Notes:New PackagesDFM 101 Part1|Dec 2008 Confidential Components that are washable are preferred

39、over those that are not.This provides maximum process flexibility.Components must be able to withstand the manufacturing process and temperature profiles.The required processing temperatures are typically higher for Pb-free assembly.Washable and ReflowableDFx Guide Section:2.1.6 Process Compatibilit

40、y RequirementsManual CheckDFM 101 Part1|Dec 2008 ConfidentialNote:1.Components should be specified to J-STD-020,which states a maximum temperature of 220C for SnPb and 260C for Pb-free(unless otherwise specified by manufacturer).2.SnPb moisture sensitive parts are acceptable at 220C3.Pb-free moistur

41、e sensitive parts are acceptable at 260CComponent Temperature RequirementsWashable and ReflowableDFM 101 Part1|Dec 2008 ConfidentialShipment PackagingDFx Guide Section:2.1.13 Component Supply/Packaging FormatsManual CheckDFM 101 Part1|Dec 2008 Confidential Remove any non-production parts prior to fi

42、nal BOM release Parts which may be candidates for removal:Header pins used only for debug of the design,e.g.grounding of oscilloscope probesSockets,e.g.to enable frequent upgrade of microcode during design debugDiagnostic connectors,e.g.to logic analyzersSmall headers/connectors spread across the bo

43、ard,e.g.for measurement of signal integrity or power distribution and noise Ask the designer if any parts are not required for productionDFx Guide Section:2.4.5Manual CheckPart Removal from BOMDFM 101 Part1|Dec 2008ConfidentialDFx Guide:2.5.1 Wave Solder PTH ComponentsValor check:c_pitch(Component A

44、nalysis)Correct pin protrusion and use of solder thieves are critical for fine pitch wave solder Solder thieves are currently required for all PTH components for Pb-free soldering(needs more study)Defect rate for fine pitch typically 10X the rate for standard pitch(SnPb data)Fine Pitch ComponentsFin

45、e Pitch PTH ComponentsDFM 101 Part1|Dec 2008 ConfidentialDFx Guide:2.1.9 Non-Preferred Components,2.2.1 Package SelectionValor check:c_pitch(Component Analysis)SMT peripheral leaded components(gullwings,leadless):Minimum recommended pitch is 0.5mm Pitches down to 0.4mm can be assembled,but with lowe

46、r yieldsArea array components:Pitches of 1.0mm and above are recommended,as they can be assembled with very low defect rates Pitches below 1.0mm can be used with caution:May have lower assembly yieldsDifficult to mix with high paste volume parts,e.g.CBGA(step stencil)Land pattern design is more chal

47、lengingMay require advanced PCB technology,e.g.micro-via,high capability solder mask(web width®istration)Pitches of 0.5mm and below are not recommended,as they are challenging to assemble with high yieldsFine Pitch ComponentsFine Pitch SMT ComponentsDFM 101 Part1|Dec 2008 ConfidentialQFP Assembly

48、 Defects by PitchFine Pitch ComponentsDFM 101 Part1|Dec 2008 ConfidentialDFx Guide Section:2.5.2 Paste-in-Hole Components,2.6.4 SMT ConnectorsManual CheckPick-up method for placement in the SMT line,in order of preference:Auto-placeable parts with a flat surface on the top of the part for vacuum pic

49、k-up(minimum diameter 7.5mm(0.3”).Some parts have a removable pick-up cap to provide a pick-up area.Flat surface on the side for side vacuum Special gripper designed for the part,or manual placement Note that a metal pick-up cap will interfere with TestJet or Opens Express(capacitive)testing at ICT.

50、SMT connector with removable pick-up capAuto placementDFM 101 Part1|Dec 2008 ConfidentialComponentsDFM 101 Part1|Dec 2008 Confidential Complex connectors may significantly impact:NRE(assembly&/or repair),e.g.custom tooling,process development or optimization,operator training for customized operatio

51、nOperation time(assembly and/or repair)Yield Often very little opportunity to change connectors,as they can be an integral part of the system mechanical design.However,feedback should still be provided on their impact to manufacturing.DFx Guide Section:2.6.4 SMT Connectors,2.6.5 PTH ConnectorsManual

52、 CheckComplex ConnectorsDFM 101 Part1|Dec 2008 Confidential Fine pitch SMT connector with rivet mechanical retention Connector must be riveted in place prior to reflow due to the lead configuration-if not riveted,it would not sit flat on the PCB surface.Riveting must therefore be done with all compo

53、nents placed in wet paste.Example:SMT MicropaxTM Leads are not flat on the componentLeads must be pressed into a flat position when mounted on the PCARivet location Leads extend underneath the connector body,making visual inspection and touch-up of solder bridges very difficult.Complex ConnectorsDFM

54、 101 Part1|Dec 2008 Confidential Panda connectorFour rows of interlaced“butt joint”connections(pinned SMT joints).Visual inspection and touch-up of inner 2 rows is almost impossible due to pitch and interlacing on pinsMetal clamp must be placed around the connector to keep it from bowing from the ca

55、rd and producing opens during reflow.Clamp acts as a heat sink making it more difficult to get the connector leads to reflowComplex Connector ExamplesComplex ConnectorsDFM 101 Part1|Dec 2008 ConfidentialConnector Mechanical RetentionDFM 101 Part1|Dec 2008 ConfidentialOther considerations:For paste i

56、n hole attach:avoid using snap-in legs unless required,as they may push solder out of the hole Kinked PTH leads may be cheaper than adding a separate hold-down feature Screws,rivscrews,&rivets may require additional assembly time,e.g.to invert the assembly,install the hardware,apply masking for wave

57、 Screws may need to be re-torque after wave solder Avoid rivets due to rework difficulty;try rivscrews instead If using screws,use captive nuts or pem nuts to reduce assembly timeConnector Mechanical RetentionDFM 101 Part1|Dec 2008 ConfidentialOther considerations:Snap-in mechanisms should accommoda

58、te the PCB thickness and tolerance(typically+/-10%)If the PCB is too thick,the part may not engage properlyIf the PCB is too thin,the part may float during soldering Install retention hardware before the part is soldered,to avoid inducing stress in the solder joints that could lead to early failure

59、Pegs that must be deformed after insertion should be avoided as they require additional assembly time and may require special equipment,e.g.ultrasonic bonder Alignment pins should have a taper and should be longer than the functional pins,so that they engage firstConnector Mechanical RetentionAlignm

60、ent PinDFM 101 Part1|Dec 2008 ConfidentialOther considerations:Retention mechanisms should be low force,so that any functional PTH pins bent during insertion can be detected To reduce incidence of bent PTH pins,the maximum installation force should be applied only after the tips of the functional pi

61、ns are inside the barrels of the PCB Mechanical retention for SMT connectors is challenging:Absence of mechanical retention,or installation of mechanical retention after soldering can both lead to early solder joint failureInstallation of mechanical retention prior to reflow risks smearing of solder

62、 paste and incurring defects in other placed components on the PCBSome preferred methods are soldered PTH pins(without latches or barbs)or SMT tabs.To facilitate rework,PTH pins should not be connected to planes,or at a minimum must have thermal reliefs.Connector Mechanical RetentionDFM 101 Part1|De

63、c 2008 ConfidentialCeramic:Parts larger than 1210 size may need additional analysis of CTE mismatch and stress cracking susceptibility to understand potential reliability effects.Avoid using high voltage surface mount ceramic capacitors.They require special processes(encapsulation)to prevent voltage

64、 flashover.Not all ceramic capacitors are wave solderable.Refer to the manufacturers specifications.Film:Not recommended due to poor solderability and rework issues.Close attention should be given to specified soldering conditions.Moisture sensitive-the manufacturers storage requirements should be f

65、ollowed.Often not suitable for wave soldering.DFx Guide Section:2.4.6 Capacitor SelectionManual CheckCapacitorsDFM 101 Part1|Dec 2008 ConfidentialTantalum:Molded parts are recommended over conformally coated parts.For lower voltage values(0.38mm(0.015)required on PTH parts to raise the part off the

66、PCB during wash.DFx Guide Section:2.4.6 Capacitor SelectionManual CheckCapacitorsDFM 101 Part1|Dec 2008 ConfidentialDFx Guide Section:2.1.9 Non-Preferred ComponentsManual checkAvoid the unnecessary use of discrete component sizes below 0603.Small Chip DiscreteDFM 101 Part1|Dec 2008 ConfidentialDFx Guide Section:2.1.8 Component Count ReductionManual CheckAdded Placement Time for Discretes vs.RpacksUse resistor packs rather than individual resistors where a number of the same value of resistor exi