Board Mounting Techniques

The survey is based on collection of data and information from these manufacturers:

Mounting related induced failures are the number one reason (over 55%) for the field application capacitor failure causes according to a EPCI end customer survey – see featured Fig.1.

The capacitor component failures itself represents “just” 33% of the root failure causes. Thus, a careful evaluation of mounting guidelines and follow up in real assembly processes per the component manufacturers’ recommendations shall be considered as a critical characteristic. This mounting guide survey report summarises recommendations, tip & tricks for the best mounting practice published by component manufacturers.

Board mounting soldering processes itself shall be adapted to contradictory requirements. On one hand, a certain minimum time in the molten solder to get a good wetting is needed and on the other hand, as short exposure to the molten solder as possible to minimize any risk of damage on component. The following items to be considered for selection of the proper mounting technique and its parameters:

• many times mounting process is „the worst electrical and mechanical stress in the component’s life“
• thermal stress may damage parts by excessive heat
• thermal stress may cause issues due to CTE mismatch
• degradation by thermally driven wear out mechanisms – diffusion, migration, increase of chemical activity …
• component history (packaging, transport) may play a key role
• strong absorbed humidity and oxidisation impact
• pre-tinning and re-soldering (SnPb solder dip) requirements
• rework option and conditions
• temperature exposure is directly proportional to the post reflow failures and ppm life failures
• PCB construction, number of layers, technology used, required volume and soldering process repeatability
• handling of components (manual/pick & place) and PCB (mechanical shock, vibration, rack/holder loading, supp

List of Standards

The following is a list of most common soldering and mounting standards used and referred by passive component manufacturers in their mounting guide specifications:

• EIA/IPC/JEDEC J-STD-002E – Solderability Tests for Component Leads, Terminations, Lugs, Terminals and Wires
• JESD22-B102E – Solderability
• IPC/JEDEC J-STD-020E – Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices
• IPC/JEDEC J-STD-033C– Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices
• ECIA/IPC/JEDEC J-STD-075 – Classification of Passive and Solid State Devices for Assembly Processes
• BS CECC 00802 – Harmonized system of quality assessment for electronic components. Guidance document: CECC Standard method for the specification of surface mounting components (SMDs) of assessed quality
• EN NF 61192 – Workmanship Requirements For Soldered Electronic Assemblies, AFNORM
• EN 61760-1:2006 – Surface mounting technology – Part 1: Standard method for the specification of surface mounting components (SMDs)
• IPC/JEDEC-EIA-625 – Requirements For Handling Electrostatic-Discharge-Sensitive (ESDS) Devices
• IPC-2221 – Generic Standard on Printed Board Design
• IPC-SM-782 – Surface Mount Design and Land Pattern Standard