INEMI 2007 Roadmap Organic Substrates. Jack Fisher, Interconnect Technology Analysis, Inc. Celestica-iNEMI Technology Forum May 15, 2007

Transcription

1 INEMI 2007 Roadmap Organic Substrates Jack Fisher, Interconnect Technology Analysis, Inc. Celestica-iNEMI Technology Forum May 15, 2007

2 Introduction The interconnecting substrates functional role provides circuit signal matching, thermal management, and mechanical support, as well as electrical functionality. Organic printed boards account for over 90% of the present types of interconnecting structures. Meeting cost expectations (while trying to meet the design intent) for high volume production continues to be a major challenge faced by the industry. Standard organic substrate boards have been (and will continue to be) the work-horse of interconnection technology for surface mount and mixed technologies. The increased wiring density driven by area array components drives the need for very small vias on tight grids, as well as fine line wiring with equivalent spacing and on multiple levels. Higher performance systems are also demanding tighter impedance controls, and high-density applications are seeking integral inductive / resistive / capacitive layers. 1

3 Cost Ratio Single Sided 0.67 Double Sided 1 Four Layer Multilayer 1.75 Six Layer Multilayer 2.25 Eight Layer Multilayer 3.00 Ten Layer Multilayer 3.50 Twelve Layer Multilayer 4.25 Fourteen layer Multilayer

4 Semiconductor - PCB Gap Figure 1: Semiconductor and organic substrate gap needs to close 3

5 PCB Industry Model Continues to Evolve 70 s 80 s Printed Board industry was dominated by captive fabrication facilities. 90 s 2000 EMS (Electronics Manufacturing Services) giants acquiring printed board fabrication facilities. Early 2000 s Very large Taiwan independents dominating Today Giant Chinese shops 4

6 Product Sectors The product emulators show requirements for printed boards of the future to offer increased wiring density (more layers with improved build-up micro-via technology); better high frequency characteristics both better materials and improved impedance control; thinner dielectric layers and lower weight. Greater emphasis is also being placed on the circuit performance contribution of the organic substrate. Environmental issues are pushing to eliminate certain bromines as a flame retardant in laminates while the move to lead-free solders means higher soldering temperatures that the printed board must withstand. 5

7 Product Sectors In today's market, the so called standard FR-4, which represented 85% of the resin system used to produce copper clad laminate is gradually disappearing. The replacement is still an epoxy, resin based material, however, the fillers and proportions of other resin makes for a variety of choices. The characteristics of epoxy resin systems will continue to evolve. 6

8 Technology Passive components that are buried inside (integral to) the printed circuit board are needed for both wiring density increases and for electrical performance reasons. The CAD systems and the board fabrication infrastructure are not as ready as they need to be in order to have full implementation capability for using embedded passives. Optoelectronic substrates with embedded waveguides are still years from being in production. 7

9 R & D in PCB s New innovations in technology, use of materials, combinations of components and their interconnecting structures have been delegated to industry material and equipment suppliers. They must do the research and commercialize it to provide a new process, equipment, or a new set of tools to be used by the manufacturing industry. 8

10 Consortia of the Future Collaborative R&D is perhaps the most viable solution available. However, the model most likely will change slightly. The biggest change will be in membership criteria. Consortia need to find ways for smaller companies and even individuals to participate. If not as full members, then perhaps on specific projects where their knowledge and proficiency will benefit all participants. Small companies with specific know-how and even small design groups or individual designers have expertise needed in some projects or activities. Greater interaction among consortia, possibly even cooperative projects. This is happening already, but on a limited basis. Many OEMs are participating in consortia on a project by project basis and want to make sure that there is no duplication of effort by consortia and that the resources they invest are providing them with a payback. If they see an advantage in two consortia joining forces for more return they are pushing for that. Some sort of "clearinghouse" where consortia activities are listed and interested companies can see who is doing what in order to participate in those activities that are most relevant and will yield the greatest results. 9

11 Product Board Substrate Technology CONVENTIONAL Available from 85% of the industry fabricators LEADING-EDGE Available from 15% of the industry fabricators STATE OF THE ART Available from less than 1% of industry fabricators Rigid Board Microvia Rigid Board Microvia Rigid Board Microvia LW / LS 75/ 75um n/a 50/ 60um 40/45um 35/35um 30/30um PTH hole size (unplated) 300 um n/a 200 um 75 um 150 um 40 um Drill Capture Land 400 um n/a 300 um 175 um 280 um 70 um Buried passives No No Very limited Yes Yes Yes 10

12 Product Board Summary Mechanical drilling is alive and well, and general products are being produced with >75 m conductors and spaces. It is of interest to note that on some products the OEM s are not pushing for further line width reduction, they are reducing land diameters instead to gain the interconnection density. The mechanical drilling industry has also kept pace with the needs of manufacturers by providing drill bits in a bucket shape where the larger part of the bit creates an opening at the top of the via hole that allows robust plating techniques of the microvia. Using these drill bits requires step drilling from external layers to the first internal layer. 11

13 Packaging Substrate Technology CONVENTIONAL LEADING-EDGE STATE OF THE ART Available from 85% of the industry fabricators Available from 15% of the industry fabricators Available from less than 1% of industry fabricators FR-4 High Temp FR-4 High Tg Epoxy RoHS compliant with low loss LW / LS 75 / 75 um 50 / 50 um 40 /40 um PTH hole size (unplated) 150 um 120 um 75 um Drill Capture Land 350 um 240 um 150 um Buried passives N/A Yes Yes 12

14 Density The total number of components attached to a single assembly is growing, while the number of functions per device is increasing. With increased complexity and increased I/O count the component manufacturer has reduced the contact pitch. Packages will have even closer perimeter lead spacing such as 0.5 mm, 0.4 mm, 0.3 mm, and 0.25 mm. The technologies used for microvia formation in build-up constructions have matured significantly, with commensurate growth in infrastructure development. Laser via formation has taken hold in a number of manufacturing sites. 13

15 Micro via traversing down to layer 3 of a multilayer structure 14

16 Flexible Substrate Technology CONVENTIONAL LEADING-EDGE STATE OF THE ART Available from 85% of the industry fabricators Available from 15% of the industry fabricators Available from less than 1% of industry fabricators LW / LS um um um Conductive layer count >12 Dielectric thickness um um 12 um Adhesives Yes Adhesiveless Adhesiveless Controlled Impedance No Yes Yes 15

17 Flexible circuit materials The following needs have been identified for flexible printed boards. The growing demand for portability fuels the demand for flexible printed boards in notebook computers, cellular phones, pagers, etc. Narrower spacing between conductors and thinner dielectric layers require dielectrics with higher break-down voltage and CAF (conductive anodic filament) resistance. There is growing demand for flex circuits in high frequency, controlled impedance circuits, particularly for telecom switching stations. Growth in displays is driving the use of flex connections from the display panel to the display driver. Reduced product lifecycles demand shorter lead times and quick rampup and ramp-down. A substantially lower cost polyimide substrate or equivalent as a prerequisite to expand flex circuitry into the domain of lower cost rigid boards. A low cost, low Dk, process-friendly dielectric for high speed applications 16

18 Sample of Surface Finish Characteristics 17

19 Substrate embedded components So far the market for this technology has been small, however, with the advent of wireless technology and high speed circuits, the need for the infrastructure to evolve is paramount. It is no longer just saving assembly real estate, it is the performance of the electronic package, module or unit requiring that resistor and capacitor devices are closely to the power I/Os of the semiconductor. Design process. Some components are easy candidates for integrating into the multilayer structure. Others are more difficult to rationalize as to the added performance value compared with the extra processing steps needed to achieve the desired results. There is no doubt that the technology of including resistive material or capacitive structures in the substrate will become a way of increasing the performance of the product being designed, and at the moment the design tools are behind the curve. 18

20 Interconnection Substrate Materials The electronic package, module, or unit assembly is subjected to environments that are often benign, and at other times the environments are relatively severe.. A substrate s ability to withstand temperature and humidity changes, and its ability to transfer heat from the components to the mounting frames, are key factors in its overall performance capability. Glass epoxy is the most popular organic resin system of reinforcement used in today's environment. However, major strides are intended to provide better characteristics in dimensional consistency and thermal or mechanical properties. 19

21 Interconnection Substrate Materials Two significant things happening today in the organic substrate materials industry. One is Pb-free solder in the assembly process and the other is bromine-free laminates for the manufacture of printed boards. Bromine containing compounds that are outlawed by RoHS are those that remain as independent molecules within the polymeric matrix. These include: 1) poly biphenyl ethers or oxides (PBDE or PBBO) and 2) poly brominated biphenyls (PBB). 20

22 Materials Cost of Ownership 21

23 Business and Technology Issues The North American substrate industry is concerned with the continuing loss of market share to the Far East. Japan is clearly the leader in microvia technology and although the North American printed board fabricators are manufacturing a few microvia boards there is no indication they are investing in this technology. Today the feature size technology leader is arguably, Japan. The North American manufacturers today dominate the high performance printed board market, but they may not maintain that lead. The Chinese are investing heavily in PWB and PCB capacity and may have the tools in place to capture a large piece of this business, but it is still uncertain if they will have the necessary technical resource required. Some OEM s are forecasting a layer count reduction in their products in order to reduce cost. If the layer count reduction is real, it may mean that the North American fabricators will lose additional market share. Although there has been a significant change in the printed board industry with the EMS companies buying up large amounts of PWB and PCB manufacturing capacity there doesn t seem to be any noticeable change in the vision of the industry. 22

24 Forecast for Product Board Attributes Current Conv. Build - up Conv. Build - up Conv. Build - up Conv. Build - up Conv. Build - up LW / LS (um) 100 / / / / / / / / / / 18 Drilled PTH hole (um) 250 N/A 250 N/A 200 N/A 150 N/A 125 N/A Capture Pad (um) 300 over drill 110 M via 275 over drill 90 M via 250 over drill 75 M via 225 over drill 60 M via 200 over drill 50 M via Microvia diameter (um) Buried passives No Yes No Yes No Yes (+ actives) Yes Yes (+ actives) Yes Yes (+ actives) 23

25 Optical Interconnect Substrate Introduction The advent of increased data rates to support growing bandwidth requirements is certain to continue. Electrical transmission of signals will presumably soon run up against its limits. Telecommunications systems appear to be the primary driver of optoelectronic interconnect technology. The developed optical wide area (WAN) and local area networks (LAN) currently use fiber based optoelectronic technology for infrastructure and hybrid fiber / organic substrates in the supporting backplanes. Optical interconnect solutions are still promising, but cost and technology reliability will determine the breakpoint. 24

26 Cost-performance is the key driver; we need an industry metric to compare optical vs. Cu-based, e.g. $/(Gb/s/channel/m) Relative Cost Crossover zone: changeover will not be immediate, but will range depending on issues including cost sensitivity, reliability, and design limitations Copper PCB Optical PCB Bandwidth x Distance 25

27 Critical Issues Paradigm Shifts A number of potential paradigm shifts could occur as a result of efforts to reach interconnection density targets under the expected cost constraints. These paradigm shifts, if they occur, will require new materials and processes beyond those in today's industry, e.g. FR-4 replacements. Increased wiring density for high I/O devices has uncovered limitations in the traditional printed board design and manufacturing techniques. High wiring density can be accommodated by increasing layer count, or through densification using sequential manufacturing techniques (multilayer or double-sided) or fully additive. 26

28 Critical Issues Paradigm Shifts Other possible paradigm shifts include: Non-reinforced substrates Non-woven substrates. Imprint Patterned Circuits based on stamped technology employed in Laserdiscs / Compact Disc production Imprinted circuits require no drilling, no photo tools, have no registration issues and utilize reduced plating 27

29 Development Needs Microvia technology improvement Microvia metallization Continuous cycle time reduction for quick turn boards Flexible circuit quick turn facilities Improved design tools for emerging technologies like embedded passives and optoelectronic PCB s 28

30 Research Needs High-performance laminates that are competitively priced Low dielectric constant Low loss Integral materials for resistors / capacitors / inductors Self reinforced materials Liquid crystal polymer that can be introduced into a PCB shop manufacturing process New non-contact testing techniques and new cost effective electrical test methods Boards without surface finishes Improved dimensional stability materials Waveguide materials and manufacturing techniques 29

31 University Research Universities actively involved in interconnection substrate research: Georgia Technical Institute (Georgia Tech) Auburn University Binghamton University Pennsylvania State University University of Arkansas? 30

32 Gaps and Showstoppers The major showstopper affecting the interconnect industry is the loss of captive R&D. The precipitous decline in substrate R&D investment does not bode well for meeting the ambitious emulator density and cost targets. In addition, the following items must be addressed: Electrical test Dimensional consistency / stability. Understanding the true cost / performance relationship Two-way communication between designers / engineers and manufacturing personnel 31

33 contact: Jack Fisher 32