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9 Trillion Solder Joints--The Occam Razor Will Cut Them Away
September 10, 2007 |Estimated reading time: 5 minutes
In 14th Century <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />England, a philosopher Franciscan friar, William of Occam, argued for choosing the simplest hypothesis--"one should not multiply entities beyond necessity", translated from the Latin. The principle has resounded through history as "Occam's Razor".
In 21st Century America, an inventor, Joseph Fjelstad, has picked up that Razor to simplify the architecture of electronic interconnections, beginning with potentially eliminating 9 trillion solder joints. That's the number that will have been used in all electronic equipment manufactured globally in the year 2007. The number was derived by adding all integrated circuit leads plus all discrete semiconductor leads. Those production levels are reported to an arm of the Semiconductor Industry Association, and documented by them. Passive components reporting is more problematic, so we made a conservative estimate[1]. Our 9 trillion total solder joints is itself a conservative estimate. We neglected connectors, transformers, and many other component categories.
The Occam Process (OP)
Occam simplifies and rationalizes interconnection architecture.
More than 50 years ago, copper traces on printed circuit boards replaced wires to interconnect components using tin-lead solder. It became the mainstream architecture for manufacturing semiconductor-based circuits. Gene Weiner tells me that he worked on an Occam like project at MIT Lincoln Labs in 1958 to replace solder joints with plated electrical connections to exposed leads potted in a cordwood style package. GE, IBM, and Motorola had other packaging activities in the 80's and 90's that also eliminated Solder in some packages. Casio has a major program under way, today, in Japan with a similar goal in sight.
Today, most of the pieces to enable Occam replacement of today's architecture are ready to go--blind vias to access component pads, electroless, electrolytic, and direct plating to connect components and traces, buildup technologies and many alternatives to form the traces. Most of the needed capital equipment and processes are also ready to go, after reconfiguration. Of course, it will take work and the generation of new ideas, but that's typical of new paradigms.
Occam's key advance is separating components and wiring so the placement and routing of each may be optimized independently of the many constraints imposed by the other. The third dimension is fully utilized with blind vias to join the two worlds without either getting in the way of the other. 9 trillion solder joints will be replaced by 9 trillion blind vias. Plasma and photo via mass formation technologies, even mechanically controlled depth drilling, will again be on the table as contenders against million dollar serial lasers for such massive numbers. The via formation process will be much less critical. Because of the large amount of real estate freed from the component substrate by using 3D interconnects, 100 micron holes and up will work. There will be no glass nor composite to drill through, only homogeneous molding compound. Production speed will be gained--that equals faster cycle time. Additionally faster bus speeds and signal cycle times will be gained by shortening paths.
Occam is not a drop-in addition to electronic assembly. It is a full integration of printed circuit fabrication technologies with assembly, modifying, reconfiguring, and joining the present skills and capital equipment of each into a new, simpler whole, shortening the supply chain, shortening the manufacturing cycle. It is even possible that North America will be a player again in electronic manufacturing.
A little talked about model that works for American PCB companies has been assembly along with fabrication. The Fabfile Online database (below) shows seven of the U.S. companies that successfully offer their customers PCB fabrication and assembly combined. They could be samples of prospective Occam Technology Partners, working with their OEM customers.
A Partial List Of North American Fabricators With Assembly Capabilities
Diversified Systems Inc.
Eagle Circuits Inc.
Endicott Interconnect
Hughes Circuits
Hunter Technology Group
Mass Design
Triangle Circuits
Occam architecture will offer positive impacts on 3 major objectives--lower cost, higher reliability, and smaller ecological damage compared to the present, "old" solder interconnection architecture.
Replacement of solder joints is a good example, one of many, but particularly appropriate, considering cost, reliability, and environmental issues raised by lead-free solder. A well-known advocate of lead-free solder talks incessantly of the 120 million reliable cell phones made by company X. He neglects to mention that they tend to open circuit when dropped. Microsoft has admitted their thermal cycling related reliability problems, one billion dollars worth of potential repairs for the X-Box.
Solder and Tin--The Economics Of Their Elimination
The purpose of the following analysis is to gauge the impact of lead-free solder on the electronics assembly industry, although Occam would practically eliminate all solder as an assembly cost element.
Lead-free solder has brought the industry to a crisis with only 55% penetration so far. New supplies of tin and silver simply aren't there even at record high prices. By pushing so hard for lead-free, the tin industry may have killed their golden goose. Occam to the rescue!
Electronic solder accounts for 49.7% of total tin usage in 2007 (CRU-ITRI), up from 29% (Murchison AR) in 2001-- the increase is primarily due to growth in lead-free solder penetration to 55% of the world market (IPC).
World usage of tin in 2001 was about 200,000 tonnes . Using the 29% figure from that source, electronic solder used 58,000 tonnes (127.6 M pounds) of tin. In 2007, a conservative 10% increase over CRU/ITRI 2005 figure for tin in solder yields 180,000 tonnes (396 M pounds).
In the interest of simplicity, we'll compare values of only the tin content of all solder, 2001 and 2007, leaving out silver and overhead. In 2001, the LME price of tin was as low as $1.99/pound. On September3, 2007, LME price of tin was $6.95.
Comparing only market values of tin in solder, capturing 2 moments in its volatile price history : 2001--$254 M and 2007-- $1, 251M. The latter figure is only an indication of an enormous toll on electronics manufacturing primarily due to lead-free solder.
Summarizing Other Savings from Occam
The total energy consumed by 27,500 assembly reflow ovens at 26 KW average for lead-free solder is 6.3B KWh, according to Karl Tiefert, formerly at Agilent (assuming l-f for all ovens).
Occam will eliminate the need for 300 Diablo-size nuclear plants.
It's too early to fully analyze the importance of the Occam process to the global and especially to the beleaguered American electronics industry. Above are samples, but the main benefits may include
- reduction of cycle time
- reduction of process steps
- reduction of labor
That is the promise and the challenge as infancy is followed by maturing stages that adapt automation.
Occcam's adoption will increase reliability and open new vistas for electronics industry packaging. It cannot happen soon enough!
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[1] IC unit estimate for 2007: 144B x 50 average lead count using Electronic Trend Publication figures = 7.2 T
Discrete semi: 400B x 2 = 800B
Passive est.: 500B x 2 = 1T
TOTAL: 9 Trillion + solder joints