The Occam Process. An Energy-efficient efficient Approach to Electronic Assembly, Interconnection, and Data Transmission Management

Transcription

1 The Occam Process An Energy-efficient efficient Approach to Electronic Assembly, Interconnection, and Data Transmission Management Joseph Fjelstad President Verdant Electronics, Inc.

2 Introduction Electronic products are the engine that has propelled the exponential growth of global knowledge over the last half century A steady stream of new products from the computer to the cell phone allow us to connect seamlessly with nearly every place and potentially every one on the planet by a combination of land lines, wireless transmitters and satellites. This comes at a cost however both in terms or materials and energy, both of which have certain limits and there are other challenges that we presently face that create a greater sense of urgency. We cannot afford to turn off the engine but neither can we continue on the path we are presently on.

3 Comparison of Projected Electricity Use, All Scenarios, 2007 to 2011 Source: US EPA Report to Congress on Server and Data Center Energy Efficiency

4 Redefining Connection Paths can Help Reduce Power Requirements Inductance Impedance changes Capacitance Impedance changes Inductance Capacitance Signal reflections Dielectric & conductor loss Signal reflections Patented

5 20Gbps High Speed Copper Channel Technological Advantages... High speed flex based channel technology Low power, non-enhanced, link between packages over extended distance, with near zero skew at speeds to >20Gbps per channel. Increased design flexibility and customization for performance Chip interconnections and package can be a commodity item Interconnection architecture can be standardized All standard materials Compatible with existing packaging assembly technology Transmit energy conservation of up to 90%

6 Civil Engineering for Electronics High speed data channel between chips and connectors Patented Simple PCB for power ground and low speed

7 Manufacturing s s Challenge As we progress, energy conservation along with materials conservation will become ever more critical to meeting the business and social objectives of expanding the reach of technology into developing parts of the world. The challenge is multifaceted and includes a need to address the environmental impact of these objectives The European Union passed and enacted in July of 2006 its Restriction of Hazardous Substances (RoHS( RoHS) legislation which among other substances banned lead from electronic solders. The impact has been far reaching and has been fraught with technical and economic challenges In this environment, an alternative approach to the manufacture and interconnection electronic assemblies is now being developed

8 Current Manufacturing Paradigm 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. Historically vertically integrated companies did it all...

9 The Assembly Industry s s Challenge 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 an ongoing concern Lead-free shifts to more expensive metal alloys Tin whiskers are a wild card issue now in the public eye

10 Lead-free concerns in the 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 lead debate San Jose Mercury News October 15th 2007

11 The Value of Interconnections Interconnections have long been undervalued are now gatekeepers of cost and performance Interconnections are also commonly the limiting factor in product reliability Improved approaches to design and manufacture of electroinic interconnections are required to meet future requirements

12 Solder - Past and Present Issues Solder has long been an important technology for making electromechanical interconnections and has been reasonably trustworthy. There are some intrinsic problems with solder but tin- lead solders have met most challenges However component lead contact pitch continues to drop and the problems with solder are becoming increasing apparent. The list things to manage and control in the soldering process is long and involved.

13 Soldering Fishbone Diagram Source: Interphase Corporation

14 The Ongoing Challenge Solder

15 Where are we today?

16 Current Electronic Manufacturing Process PWB DESIGN PWB FABRICATION Engineering Laminate Drill Plate Image Etch Mask Route INVENTORY, STORAGE SMT ASSEMBLY Stencil paste Inspect Place parts SCHEMATIC BOM ASSEMBLY DESIGN RELIABILITY ASSURANCE SOLDER, PASTE, FLUX Inspect Reflow Clean PARTS ENGINEERING PROCURE PARTS Storage & Inventory Inspect Test

17 Basic PWB Manufacturing for Double Sided Boards

18 Select Appropriate Foil Clad Laminate

19 Drill Hole Pattern for Vias & Components

20 Make Through Holes Conductive

21 Coat Panel with Photoresist

22 Align Patterned Phototool to Hole Pattern

23 Expose to UV Light Source

24 Develop Unexposed Pattern

25 Plate Copper on to Exposed Pattern Area

26 Plate Finishing Metal(s) (Solder, Tin, Nickel, Palladium, Gold, etc. either Temporary or Permanent)

27 Strip Resist from Plated Circuit

28 Etch Background Copper Foil

29 Strip Etch Resist Metal

30 Coat with Solder Mask (Screen Printed or Photoimaged)

31 Coat Exposed Copper (solder, electroless Ni/Au or OSP)

32 Example of Build-up Board Manufacturing Process Steps

33 Prepare Innerlayers

34 Laminate Layers

35 Drill Through Holes

36 Seed Hole with Conductive Film

37 Coat with Photoresist

38 Image Resist Pattern

39 Plate Copper Traces

40 Plate Etch Resist Metal

41 Strip Resist Exposing Base Copper

42 Etch Background Copper

43 Strip Etch Resist Metal

44 Fill Holes with Resin

45 Coat with Photoimagable or Filled Polymer

46 Image and Develop or Laser Drill Holes in Polymer

47 Metallize Surfaces with Copper

48 Expose and Develop Photoresist

49 Pattern Plate Copper Circuit Image

50 Strip Resist & Expose Seed Layer

51 Etch Copper Seed Layer

52 Coat with Soldermask

53 Expose and Develop Soldermask

54 Apply Solderable Finish (e.g. PbSn)

55 Basic Process Steps for SMT Fixture Stencil solder paste and inspect Place components and inspect Reflow solder Clean Underfill critical components Depanelize Test and rework Ship

56 Abbreviated Occam Concept 1. Position and bond various tested components on a temporary substrate or permanent carrier 2. Encapsulate the tested 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.

57 Sample Process Sequence Patents pending

58 The Basic Occam Process ASSEMBLY DESIGN CIRCUIT DESIGN Place fully tested parts SCHEMATIC BOM RELIABILITY ASSURANCE Encapsulate parts Build up circuits Singulate PARTS ENGINEERING PROCURE PARTS Storage & Inventory Test

59 Supply Chain Compression Components IC Packages Resistors Capacitors Inductors Diodes Interconnections PCBs Sockets Connectors Cables Components IC Packages Resistors Capacitors Inductors Diodes Assembly Stencil printing Pick and place Reflow Clean Box build Occam A ssembly Pick and place Com ponents & Connectors Encapsulate Build up Circuits Box build

60 The Occam Approach is Novel but Not the Technologies but Not the Technologies Components can be placed conventionally Many suitable encapsulants available Suitable CTE, low shrinkage, high thermal conductivity Need not withstand soldering temperatures New low pressure molding techniques are available Many possible options for via creation Semi-additive fabrication process well established Improved process materials coming on line All copper system both possible and advantageous Appropriate for all classes of products Testing and rework... Philosophical questions? Why do parts fail? What are the causes of rejects?

61 Early Kitchen Prototypes

62 Occam Benefits Analysis

63 No Printed Circuit Required No PCB procurement No PCB testing required No spare PCB inventory or shelf life issues No Conductive Anodic Filament (CAF) concern No surface finish process durability problems No high temp component warp or PCB damage Lower overall material use (near zero waste) All copper circuits created in situ Novel integral connector structure possibilities

64 No Soldering Required Eliminates several manufacturing processes RoHS restricted material concerns obviated No solderability testing or surface finish concerns No high temperature damage to devices or PCB Energy use is reduced (no bakes or reflow) No solder shorts, opens, micro voids, copper dissolution and the host of other common solder related reliability issues and concerns Limited post assembly cleaning & testing issues

65 Reduced Component Concerns Only fully tested and protected components used No solder build up on tester/socket contacts No component leads = No coplanarity issues No surface finish solderability issues Fewer component types needed (LGA & QFN) Smaller component libraries possible (Pkgs( Pkgs) Lower cost (simpler) & higher yield on devices No MSL issues or popcorning concerns Improved routing for area array IC packages Overlapping of components is possible

66 Overlapping Components Patents pending

67 Package Under Package (PuP( PuP)

68 Copper Terminated MLC Thin and Thick Film Terminations 0805 Thin Film T Thin Film Thick Film Termination Thin Film Termination 2-4 mils (75 microns typ) >1 mil (20 microns typ) Clearance (space between the part and the board) 0805 Thick Film

69 Occam Benefits Circuit Design Simplification Components can be placed closer together Increased routing capability

70 QFP/QFN Routing Advantage Routing channel opportunities limited on substrate because of solder lands increasing layer count Routing channel opportunities increased on substrate as circuits can be routed over lands allowing for layer reduction

71 BGA Routing Advantage Routing channel opportunities limited on both substrate and package Routing channel opportunities increased on both substrate and packing allowing for layer reduction

72 The 80% Design Rule Challenge

73 Effect of Multiple Pitch and Ball Variation

74 Effect of Multiple Pitch and Ball Variation 80% Rule for Pitch with 60% Rule for Pad

75 A Simpler Alternative?

76 Simplifying Layout

77 Single Lead Pitch Advantage

78 Improved Routing = Layer Reduction Courtesy: Happy Holden

79 HDI - Price/Density Comparison Source: Happy Holden RCI: Rel price to 8L DEN: Ave pins/sq.inch

80 The Future of Electronics?

81 Occam Benefits Circuit Design Simplification Components can be placed closer together Increased routing capability Dead leads ignored for additional routing Simpler and faster reconfiguration and ECOs Improved design security potential Integral heat spreader redefines placement rules Completed assemblies can interconnected

82 Stacking Assemblies Connectors Vertical Via Grid Structure Heat sink Patents pending

83 Occam Benefits Circuit Design Simplification Components can be placed closer together Increased routing capability in less space Dead leads ignored for additional routing space Improved design security Integral heat spreader redefine placement rules Simpler and faster reconfiguration and ECOs Completed assemblies can interconnected Adaptable to optoelectronics Can be used for flexible circuits

84 Occam Benefits Reliability Improvement Simple structures with fewer elements Lower temperature processing avoids thermal damage caused by lead-free soldering Components are fully encapsulated increasing shock and vibration immunity Hermetic structure possibilities with full metal jacket protection Total EMI and ESD protection possibilities Integral heat spreader improves device life

85 Solderless Assembly Allows Thermal Concerns to Be Addressed Upfront Patents pending

86 Testing is believed to be critical Why? Most testing is predicated on the anticipation of manufacturing related defects and faults What about Testing? Shorts and opens are accepted as facts of life Lead-free assembly damage to assembly components Current assembly technology has limits Simpler processes should yield higher The ultimate test is assembly turn on Can time and money for test be better allocated?

87 What and Where are the Problems? Stig Oresjo Blending Test Strategies for Limited-Access Boards Circuits Assembly Aug 2002

88 Simple Cost Comparison Model

89 Conventional SMT Line Kitting, Feeder Setup X-ray $50K Solder Printer $75K P&P Machine $200K Reflow Oven $55K Water Wash Machine $80K Solder Paste Measurement Station $15K Ionograph $15K Equipment with ~capital cost Source: Richard Otte, Promex Industries

90 Conventional SMT Line Cost Capital Cost = $440K, 5yrs, 1 shift Sq ft. 50 x 10 = 500@ $2.00/mo Power, Kw = 32.5 $0.15/Kwh Operators 1.5 $20/hr Cost per hour = $80.72 Line will place 10,000 parts/hr SAC305 costs 0.1 cent/part or 10,000 parts/hr. Total Cost, ex-interconnect is: $90.72/hr Source: Richard Otte, Promex Industries

91 Occam Process Line Kitting, Feeder Setup X-ray Solder Printer P&P Machine $200K Reflow Oven Water Wash Machine Solder Paste Measurement Station Encapsulant Dispenser $75K Encapsulant Cure Station $5K Interconnect deposition $? Ionograph Source: Richard Otte, Promex Industries

92 Occam Process Line Cost Capital Cost = $280K Sq ft. 20 x 10 = 200 Power, Kw = 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/cm 2 mm thickness or parts/cc or 10,000 pts/hr. Total cost, ex-interconnect is: $60.38/hr, 33% less Source: Richard Otte, Promex Industries

93 Alternative Solderless Structures

94 Alternative Solderless Structures programmed Patents Pending

95 Direct Write Rapid prototyping potential is compelling Patents Pending

96 Co-Design to Compress Time IC Design Package Design PCB Design Time to Market Reduction

97 Proof of concept Occam Roadmap 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

98 Alternative Future?

99 A mind, once stretched by a new idea, never returns to its original dimensions. ~ Oliver Wendell Holmes ~ American Philosopher and Jurist Thank you