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An Alternative Method for An Alternative Method for Manufacturing Robust Manufacturing Robust Electronic Assemblies Electronic Assemblies
Without SolderWithout SolderJoseph Fjelstad
PresidentVerdant Electronics
Outline • Introduction• Background• The Occam Process • Benefits Analysis• Alternative Structures• Occam Roadmap• Summary and Conclusion
Introduction• Change is the defining element of evolution • In electronics most change has been voluntary to meet
customer needs and as well to control cost in order to make products more broadly available to benefit a broader base.
• Some change is mandated by legislation (e.g. RoHS) • The electronics industry is in the midst of trying to comply
with that mandate. • It has been neither easy nor 100% successful with many
questions and concerns still unaddressed. • In this environment a new approach has been conceived
and is rapidly heading into development.
• Electronics manufacturing presently comprises three basic manufacturing industries:
• Electronic component manufacturing industry – ICs, electronic modules, discrete devices, etc.
• Electronic interconnection manufacturing industry– PCBs, package substrates, sockets, connectors, cables, etc.)
• Electronic assembly industry– Soldering, testing, box build, etc.
• Vertically integrated companies of the past did it all.
Electronics Manufacturing Today
• Electronics have historically increased functionality of products while size, weight and cost have all decreased with each new generation of product
• The trend continues but it slope of the curve is flattening and becoming more asymptotic.
• Lead pitches are decreasing, this is impacting both design and manufacture of PCBs and assemblies
• Product life and reliability are also being impacted
• Supply chain is growing longer and less manageable
• Concerns over lead-free soldering are on the rise
Electronics Assembly Challenges
In the Recent News… • “RoHS remains a $30B problem”
– Design News July 31st 2007
• “EU ban increases worries over 'whiskers' “– San Jose Mercury News October 8th 2007
• “Peril: Tin ‘whiskers’ that ruin electronics”– Corvallis Gazette October 8th 2007
• “Lead Phase-out May Destroy Electronics”– LA Times October 9th 2007
• “'Tin whiskers' in electronics stoke anti-lead debate”– San Jose Mercury News October 15th 2007
The Value of Interconnections• Interconnection technologies have long
been undervalued but they are now gatekeepers of cost and performance
• Interconnection technologies are also often the limiting factor in product reliability
• Improved interconnection technologies are required to address future needs
Solder - Past and Present Issues• Tin-lead solder provided reliable electronic
interconnections, however lead-free solder is generating concerns in shock and vibration
• There are some intrinsic problems with solder but they are more easily addressed with tin-lead
• As lead contact pitch drops with every new component shrink, the problems with solder are becoming increasing apparent.
• Lead-free impact has been negative and expensive • Metals cost is rising (Tin has tripled since 2001)
The Occam Process
1. Position and bond various components on a temporary substrate or permanent carrier
2. Encapsulate the components in place
3. Remove from substrate, expose terminations.
4. Interconnect terminations by additive or semi-additive board fab methods or alternative direct interconnection methods.
Abbreviated Occam Concept
Sample Process
Sequence
Patents pending
CONVENTIONAL SMT ASSEMBLY
SCHEMATIC BOM
PWB DESIGN
ASSEMBLY DESIGN
SMT ASSEMBLY
PARTS ENGINEERING
PROCUREPARTS
SOLDER, PASTE, FLUX
INVENTORY, STORAGE
RELIABILITY ASSURANCE
PWB FAB, PROCURE
Storage & Inventory
VERDANT ELECTRONICS’ OCCAM PROCESS
THE OCCAM PROCESSSCHEMATIC
BOM
ASSEMBLY DESIGN
PARTS ENGINEERING
PROCUREPARTS
Storage &Inventory
CIRCUIT DESIGN
Supply Chain Compression
Components IC PackagesResistorsCapacitorsInductorsDiodes
Interconnections PCBsSocketsConnectorsCables
Assembly Stencil printingPick and placeReflowCleanBox build
Components IC PackagesResistorsCapacitorsInductorsDiodes
Verdant Assembly Pick and placeComponents & ConnectorsEncapsulateBuild up CircuitsBox build
The Occam Approach is Novel…but Not the Technologies
• Components are placed conventionally• Many suitable encapsulants available off the shelf
– Suitable CTE, low shrinkage, high thermal conductivity– Materials need not withstand soldering temperatures
• Vias can be made by laser or other methods– Photolithographic materials can work
• Additive fabrication process well established– All copper system should prevail– Plating to other finishes is unconventional (is it an issue?)
• Appropriate for all classes of products• Testing and rework... Philosophical questions?
– Use known good parts and robust processes– Repair is possible but there are issues
Benefits Analysis
• No PCB procurement• No PCB testing required• No spares required• No shelf life issues• No finish solderability concerns• No high temperature board warpage concerns• Low material use and near zero waste• All copper system possible• Edge card connections are still possible
Occam BenefitsNo PCB
• RoHS restricted material concerns eliminated• No solderability testing and finish concerns • Solder inspection required is not required • No high temperature damage to devices or PCB • Reduced energy use (no bakes, no reflow) • No post assembly cleaning concerns (e.g., SIR,
dendrites and fidelity at high frequency) • No solder shorts, opens or other solder related
assembly yield and reliability issues• Reduced steps and materials = reduced cost
Occam BenefitsNo Soldering
• No solderability or ROHS compliance checks• No component leads = No coplanarity issues• No thermal warping concerns• No MSL issues or popcorning concerns • Fewer component types needed (LGA & QFN)• Smaller component libraries possible (Pkgs) • Lower cost & higher yield on devices• No solder build up on tester/socket contacts • Improved routing for area array IC packages• Overlapping of components is possible
Occam Benefits Simpler Components
Overlapping Components
Patents pending
• Components can be placed closer together• Increased routing capability
Occam BenefitsCircuit Design Improvment
Alternative RoutingOffers Layer Reduction
QFP/QFN Routing Advantage
BGA Routing Advantage
Single Lead Pitch Potential
HDI - Price/Density ComparisonHDI - Price/Density Comparison
RCI: Rel price to 8LDEN: Ave pins/sq.inch
Source: Happy Holden
The Future of Electronics?
• Components can be placed closer together• Increased routing capability
Occam BenefitsCircuit Design Improvement
• “Dead” leads ignored for additional routing• Simpler and faster reconfiguration and ECOs• Improved design security with opaque encap• Integral heat spreader redefine placement rules• Completed assemblies can interconnected
Connecting Assemblies
Patents pending
Integral multi row edge connectors of various embodimentscan be directly interconnected to assembly as a component. Caps may be used to protect contact surfaces during assembly
Stackingand
InterconnectingOccam
ProcessedAssemblies
Patents pending
• Components can be placed closer together• Increased routing capability • Components can be placed closer together• Increased routing capability in less space • “Dead” leads ignored for additional routing• Simpler and faster reconfiguration and ECOs• Improved design security• Integral heat spreader redefine placement rules• Completed assemblies can interconnected• Adaptable to optoelectronics• Can be used for flexible circuits
Occam BenefitsCircuit Design Improvement
Occam Process for Flex Circuits
Tested and burned in com ponents are positioned fo r assem bly on a flexib le film
Occam Process for Flex Circuits
The com ponents are seal bonded on bottom and a t least partia lly encapsulated on filmThe com ponents are seal bonded on bottom and a t least partia lly encapsulated on filmO ptiona l support carrier can be used to facilita te processing, H ow ever com ponent s ide can be p la ted and sealed w ith m etal for ESD , EM I or heat spread ing if desired
Occam Process for Flex Circuits
H oles are drilled (e .g. U sing a laser) to access contacts on packages and com ponents
Occam Process for Flex Circuits
P lating and im aging processes create c ircu its and in terconnection to contacts. S tepsm ay be repeated to create additional c ircuit layers as needed
Occam Process for Flex Circuits
C over layer is applied to top final circu it layer to pro tect conductors
Occam Process for Flex Circuits
Carrier if used, is rem oved and the flex c ircu it can be bent into desired shape.
Patents Pending
EDA Support Emerging• Lack of integrated EDA tool flow creates gaps
between circuit design and manufacturing however, some EDA tool suppliers sense opportunity and are getting involved early
• Co-design of all elements needed for optimum system performance is easier with Occam– Electrical, mechanical and thermal analysis
• Signal integrity will increase in importance
• Verification and design accounting for multi-dimensional analysis for complex systems
Co-Design Compresses Time
IC Design Package Design PCB DesignIC Design Package Design PCB Design
Time to Market Reduction
• Simple structure with fewer elements• Lower temperature processing avoids thermal
damage caused by soldering • Components are fully encapsulated increasing
shock and vibration immunity• Hermetic structure possibilities with full metal
jacket protection • Total EMI protection possibilities• Integral heat spreader assemblies help to
extend life of IC devices
Occam Benefits Improved Reliability
• Testing is believed to be critical… but is it?• Testing implies defects are anticipated • Test finds faults of weak manufacturing
– Shorts and opens are accepted as facts of life– Lead-free assembly can damage components
• Stencil printing paste has physical limits• Simpler processes should yield higher • The ultimate test is assembly turn on• Can time and money for test be better spent?
What about Testing?
Cost Comparison
Model
Conventional SMT Line
Water Wash Machine$80K
Solder Paste Measurement Station $15K
Kitting, Feeder Setup
Solder Printer$75K
P&P Machine$200K
Reflow Oven$55K
Ionograph
$15K
X-ray$50K
Equipment with ~capital cost
Source: Richard Otte, Promex Industries
• Capital Cost 15+75+200+55+80 = $440K, 5yrs, 1 shift• Sq ft. 50 x 10 = 500@ $2.00/mo• Power, Kw 0.5+2+25+5 = 32.5 Kw @ $0.15/Kwh• Operators 1.5 persons @ $20/hr• Cost per hour = $80.72• Line will place 10,000 parts/hr• SAC305 costs 0.1 cent/part
or $10.00/hr @ 10,000 parts/hr.
Total Cost, ex-interconnect is:$90.72/hr
Conventional SMT Line Cost
Source: Richard Otte, Promex Industries
Occam Process Line
Water Wash Machine
Solder Paste Measurement Station
Kitting, Feeder Setup
Solder Printer P&P Machine$200K
Reflow Oven
Encapsulant Dispenser $75K
Encapsulant Cure Station $5K
X-ray
Ionograph
Interconnect deposition $?
Source: Richard Otte, Promex Industries
Occam Process Line Cost
• Capital Cost 200+75+5 = $280K• Sq ft. 20 x 10 = 200• Power, Kw 2+1+5 = 8 Kw• Operators 1.0 person• Cost per hour = $50.38• Line will place 10,000parts/hr• Encapsulant costs 2 cents/cc
or 0.4cents/cm2 @ 2 mm thickness or 0.1cents/pt. @4 parts/cc or $10.00/hr @ 10,000 pts/hr.
Total cost, ex-interconnect is:$60.38/hr, 33% less
Source: Richard Otte, Promex Industries
Alternative Structures
Alternative Solderless Structures
programmed
Patents Pending
Occam and Direct Write Technology
Occam Process - Direct Write
Direct print technology can be used to create insulation and circu its d irectly onto contacts after m old ing and re leasing the assem bly from a tem porary carrier. A m echanical or chem ical m echanical process can be used prior to processing to clean leads
Ink jet printer
Patents Pending
Occam Roadmap
The Occam Process Roadmap
• Proof of concept• Test vehicle identification and reliability testing• Standards development – for design and performance• Simple products first (like early SMT) • Increase complexity with captured experience• Explore alternative solderless assembly methods• Engage Material & Equipment Suppliers with new
product and process opportunities • Suitable materials identified and characterized• Process qualification and technology transfer
SummaryCurrent assembly technology problems continue
1. Regulatory imperatives for lead-free electronics.• Very high process temperatures with lead-free solder.• Increased whisker risk from extensive use of tin plating.
2. Process challenges continue • Solder paste deposition process is highly variable.• Mixed finishes are a concern and supply chain challenge• Thermal damage to PCBs increasingly common
3. Never ending drive to reduce size and cost.• Increased density = Reduced pitch = Increased problems
4. Global sourcing and supply-chain expansion.• PWB fabrication largely moved or moving off-shore.• Components with tin-lead finish are disappearing • Limited support for new technology development by EMS
companies with sunk costs in existing equipment
A Shared Opportunity• No one company can change the entire
industry. It requires a shared effort
• Only those who appreciate the opportunity will respond early… the others will follow
• Early adopters will share the risks but also reap greater rewards. OEMs know this well.
• Change will happen… it always does.
• Question: Will the industry drive for change or wait to be legislated to change again.
The Learning CurveNew Technology
Cos
t
TimeSource BPASource BPA
Incumbent Technology
• Change is constant and inevitable • Simpler solutions are generally better• More can be done with less• Evolution generally favors those who
are prepared and willing to accept and adapt to change
Final Thoughts…
“Whatever you can do or dream you can, begin it. Boldness has genius, power and magic in it.
Begin it now.” ~Johann Goethe~
Thank You