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Design007-June2022

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JUNE 2022 I DESIGN007 MAGAZINE 89 Project phase Traditional Manufacturing Occam/SAFE Processing Design Interconnection Design Complex due to lack of fixed grid Simple Manhattan grid route Interconnection Layers Nominal ~30-50% less (standard grid) Design software Complex (multiple lead pitches) Simpler (standard grid route) Drill and pad size Varies Single option possible Component formats Numerous types (legacy carryover) Fewer when standard grid used Equivalent design size Greater and more layers required Smaller up to 50-70% smaller Component spacing Further apart (rework and cleaning) Closer (encapsulated assembly) Part to part shielding Post assembly Integral (designed in carrier) Stacked assembly Difficult Easier to plan and execute Procurement PCB (circuit) production Required None (direct component connect) Material options Limited Many (limited thermal exposure) Material cost Higher Lower (lower temperature processes) Time to market Longer Shorter (fewer steps in process) Supply Chain Longer Shorter—fewer materials required Infrastructure needed Greater Less (less special equipment) Conflict materials Requires verification None required Assembly issues Assembly complexity Greater—huge component variety Simpler due to more standardization Solder stencil maintenance Routine and required None Thermal excursions Several high temp soldering steps Fewer, lower temp steps Component storage Environmental control required Limited to no concern Solderability Important for components and PCB Unimportant Solder related problems Endemic Obviated Lead-free solder issues Yes None Inspection requirements Multiple places Fewer (reduced process steps) Test requirements Many Few (component burn in ) Post assembly cleaning Varied difficulty component dependent Easier (intrinsic/in process) Component/PCB warpage Solder temp related concern Limited Performance Thermal management More challenging Integral metal core ESD/EMI management Post assembly with formed metal shields Integral w/plated metal exterior) Hermeticity Box level or conformal coat Integral w/plated metal exterior) Signal integrity Challenging due to mixed grid pitch Easier Reliability Nominal (solder quality dependent) Better (fewer interconnections) CTE Control Nominal to challenging Better and easier CAF concern Nominal (worse at fine via pitch) Obviated by process and structure Microvia reliability Nominal (assume staggered vias) Better – stacked or staggered Strategic Design security Limited More secure (encapsulated BOM) Environmental impact Nominal to worse Lower Packaged chiplet amenable Varies Chiplet friendly—LEGO model Familiarity/experience Established Limited presently but logical Table 1: Occam/SAFE processing comparison with traditional PCBA manufacturing. Note: The value judgements cited above are subjective but based on decades of objective observations and analysis of industry technical literature which routinely describe the problems related to the manufacturing processes which can manifest defects and failures in PCB assemblies. Premise: Better to first do the right things right than to do the wrong things perfectly.

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