SMT Process Guideline and Checklist - IPC

1 IPC-S-816 SMT Process Guidelineand ChecklistASSOCIATION CONNECTINGELECTRONICS INDUSTRIES2215 Sanders Road, Northbrook, IL 60062-6135 Tel. Fax standard developed by IPCO riginal PublicationJuly 1993 Table of , Safety, and IndustrialHygiene Considerations .. Documents .. Discharge (ESD) Concerns .. Leads .. Handling .. INSPECTION OF MATERIALSAND .. PASTE Printing .. Printing .. Condition: Wrong ComponentOrientation .. Condition: Wrong componentplaced on board .. Condition: Missing Component .. Condition: ComponentMisalignment .. Condition: Condition: No Reflow .. Condition: Solder Balls .. Condition: Charring of Board/Components .. Condition: DamagedComponents .. Condition: Cracked Joints.

2 Condition: Insufficient Condition: Bridging .. Condition: Voids .. Condition: Opens .. Condition: Spatter .. Condition: ComponentAlignment .. Condition: Delamination .. Condition: Condition: Disturbed Joints .. Condition: PHASE REFLOW .. Condition: Solder Condition: Solder Bridges .. Condition: Unfilled Via Condition: Solder WaveOverflooding Board .. Condition: Grainy orDisturbed Joints .. Condition: Cold Joints .. Condition: Solder Ballson Assembly .. Condition: Cracked ChipComponents or Plastic-Bodied LeadedComponents .. Condition: Visible Residue .. Condition: Failure of and guidelines .. Heating Methods .. and Auxiliary Systems and Component Placement .. Optimum Method of.

3 Condition: Insufficient solderreflow to affect SMD removal .. Condition: Component notremovable after solder reflow or lifted landsupon attempted removal .. Condition: Lands being lifted ordamaged during removal of old Condition: Insufficient or pooradhesion of solder on lands duringpretinning operation .. 32 July Condition: Misalignment ofcomponent to land pattern during Condition: Dispersion orsolderballing of solder paste during reflow .. Condition: Blistering or measlingof substrate, or lifted lands during SMDinstallation or removal .. 32 IPC-S-816 July 1993vSMT Process Guideline and SCOPEThis document is intended to provide guidelines and assis-tance in performing and troubleshooting the steps involvedin the Process of producing printed wiring assembliesincorporating surface mounting attachment of section contains a list of problems often observedduring a specific part of the surface mount assembly pro-cess.

4 The list of observed symptoms is matched by adescription of causes often associated with the for correction are also included. These solu-tions may be related to the equipment, materials, or , some of these corrective measures cannot beimplemented on the shop Environmental, Safety, and Industrial Hygiene Con-siderationsThe use of some of the materials referencedin this document may be hazardous. Precautions should betaken to safeguard personnel and the environment, as out-lined in the appropriate data supplied with the materialsused. In addition, equipment and procedures should adhereto applicable local and federal Applicable DocumentsThe following documents, ofthe issue currently in effect, are applicable to the extentspecified IPC1 IPC-CH-65 guidelines for Cleaning of Printed Boards andAssembliesIPC-OI-645 Standard for Visual Optical Inspection AidsIPC-R-700 Suggested guidelines for Modification,Rework, and Repair of Printed Boards and AssembliesIPC-SM-782 Surface Mount Land Patterns (configurationsand Design Rules)IPC-SM-786 Recommended Procedures for handling ofMoisture Sensitive Plastic IC PackagesIPC-SM-840 Qualification and Performance of PermanentPolymer Coating (Solder Mask)

5 For Printed Joint Industry Standards1J-STD-002 Solderability Test for Component Leads, Ter-mination, Lugs, Terminals and WiresJ-STD-003 Solderability Tests for Printed BoardsJ-STD-004 Requirements for Soldering FluxesJ-STD-005 General Requirements and Test Methods forElectronic Grade Solder HANDLINGH andling is one topic that is not confined to a specific areaof the manufacturing operation. Handling problems are a cradle to grave issue for which no one will claimresponsibility; yet the impact on the surface mount processyield is substantial. Every major step covered in this guide-line, from adhesive application to cleaning of surfacemount assemblies, relies on a comprehensive componentand assembly handling strategy.

6 Handling can t be the con-cern of a single group in the manufacturing environmentand must be an integral part of each Process step in thesurface mount assembly line. Although the general formatof this document is problem-cause-corrective action, thefollowing handling items need to be considered throughoutthe entire surface mount assembly Electrostatic Discharge (ESD) ConcernsThe fol-lowing are ESD concerns:1) Has Process machinery been properly grounded?2) Have work stations and storage areas been properlygrounded?3) Are other environmental controls ( , ionizers, humidi-fiers, etc.) in place to reduce the occurrence of ESD?4) Have operators and all other employees who mayhandle components or surface mount assemblies beenproperly trained to use ESD precautions such as wriststraps or other similar preventative measures?

7 5) Have the component packaging and assembly contain-ers been reviewed for potential ESD problems?6) Have ESD sensitive parts been identified and suffi-ciently protected? Component LeadsThe following are concernsregarding component leads:1) Has component lead coplanarity been addressed follow-ing manual or automatic lead forming operations?2) Has component lead solderability concerns in relation tohandling been reviewed and precautions taken wheredeemed necessary? StorageThe following are concerns regarding stor-age:1. IPC, 2215 Sanders Road, Northbrook, IL 60062 June 1993 IPC-S-8161