In pursuit of lowest cost/watt, module manufacture will be outsourced to EMS partners.

An economic crisis is not the best backdrop for any event, but as was clear at the World Future Energy Summit held in January in Abu Dhabi, the downturn has done little to dent the alternative energy industry’s optimism – or its potential. In his review of the event for Time, Bryan Walsh noted that developers of renewable energy “know they’ll win.” This is because once the downturn has ended, demand for energy will continue to rise and “no one – including oil giants of the Middle East – believes that fossil fuels alone will meet that [demand].”¹ The German Advisory Council on Global Change agrees, stating that, by 2100, 80% of energy must be generated from renewable sources.²

The world’s political heavyweights too are adding their support for cleaner energy. In Abu Dhabi, the UK’s former Prime Minister Tony Blair called for a new global deal that would set tough interim targets up to 2020, giving business a “clear, unequivocal signal to invest in a low-carbon future.”³ Last year, in launching his country’s National Mission on Solar Energy, India’s Prime Minister Dr. Manmohan Singh promised to “…pool all our scientific, technical and managerial talents with financial sources to develop solar energy […] to power our economy and transform the lives of our people.”⁴ But perhaps most significantly for the wider global context, President Barack Obama pledged in his inaugural speech to “harness the sun and the winds and the soil to fuel our cars and run our factories.” In January, he was quick to follow his promise with his proposal to launch his stimulus bill, a massive (and much-discussed) program designed to boost the economy with measures that include hefty support for alternative energy industries.

It is therefore clear the fundamentals driving the photovoltaics (PV) industry – the need for secure, sustainable, low-cost energy, as well as solid government backing – are as robust as ever. All of which points to an industry with a great future.

This makes PV manufacture an attractive proposition for electronics companies on the lookout for new revenue streams, especially as the technology used is well within the comfort zone of most SMT companies and Tier 1 EMS providers. For example, the wet chemistry, printing and post-print curing processes used to manufacture PV cells, even if they imply something of a learning curve, are nevertheless similar to those used for PCB assemblies. The challenge, if anything, is to produce quality, high-resolution solar cells repeatably and reliably at the PV industry’s considerably faster three-second beat rate, without damaging the extremely fragile, expensive silicon substrates. Thus processing and handling equipment must be chosen carefully for built-in high-speed precision, handling and resolution capabilities.

As electronics companies consider the PV manufacturing arena, it is natural to focus on the benefits it offers, but we should also remember this is a two-way street. Our company, for example, is applying known printing principles used in the advanced electronics manufacturing arena to extend their value in cost-effective production to parallel industries such as PV cell manufacture. Similarly, as New Venture Research Corp. concluded in a study conducted early last year, EMS providers will be key to the success of the solar panel manufacturing industry.5 This is because they have accrued an impressive raft of skills that range from technological know-how and Lean manufacturing to business acumen and resource management that will enable the PV industry to reduce costs and improve processes and efficiencies significantly. Key for a fast-growing industry that only recently has transitioned from niche status, EMS providers can also provide advanced logistics capabilities for improved supplier management and materials handling, as well as support for rapid ramping to volume production.

Many EMS providers also add the advantage of location – and even multiple locations. This, in combination with their other offerings, makes them ideal module assembly partners, setting arrays of solar cells into panels for companies whose capital-intensive solar cell fabrication plants may be based in lower-labor-cost countries such as China and India. In this way, they reduce the costs of manufacture while offering a route – and even distribution proper – into lucrative target markets.

One such example is Celestica, which commenced module assembly at its Valencia plant last year, and Jabil Circuit, which concluded an agreement in December to manufacture solar modules for Day4 Energy. As the PV industry chases lowest cost/watt, this business model is likely to catch on, and we can expect to see more cell producers outsourcing their module manufacture to EMS partners, just as we can expect to see growing and increasingly profitable synergies developing between the broader electronics and PV industries.

References

1. Bryan Walsh, “Will Green Enterprises Survive the Economic Crisis?” Time, Jan. 22, 2009.
2. World Energy Council, Survey of Energy Resources 2007.
3. Terry Macalister, “Tony Blair Insists Economic Downturn Must Not Hamper Green Energy Plans,” The Guardian UK, Jan. 21, 2009.
4. BBC News, India Unveils Climate Change Plan,” June 30, 2008.
5. New Venture Research Corp., “EMS Manufacturers Come to the Rescue of Solar,” January 2008.

Darren Brown is business development manager, alternative energies at DEK International (dek.com); dwbrown@dek.com. This column will run periodically.

The two processes don’t talk to each other. They should.

Not long ago, I was on a tour at a small contract manufacturer’s site that prides itself on quality. This EMS builds medical and aerospace products, among other things. In speaking about its quality plans and how it defines quality, there was a thorough review of the test and inspection plans that includes manual visual inspection (MVI), automated optical inspection, automated x-ray inspection, in-circuit test and rework. (We did not explore functional test.) Seeing the rework step included in its overall quality plan and part of the test and inspection discussion, I realized this is a very logical inclusion; one I previously had not entertained. I have written and read many papers mentioning rework and how by using AOI, AXI and ICT, a board assembler can reduce rework, impact rework costs, and so on. However, I had never educated myself on rework from the perspective that it could be included in the test and inspection suite.

I decided to invest some time in learning more about rework. I understood the standard definition of rework, which is the process of removing a faulty component from a PCB and then soldering a new component. I also would categorize the process steps associated with rework to include finding a failed component, removing it, residual solder removal and soldering a replacement component with appropriate reflow. However, when I envision a rework station in a production environment, I think of a workstation with an operator using a software interface from an upstream process (i.e., AOI, AXI, ICT) to determine where a fault is and take repair action. My idealistic view shows the inspection steps from the first-pass production communicating with the rework station in a tidy, closed-loop setup. After some investigation, I have determined this is not as likely as I thought.

I have some familiarity with hand-soldering and manual rework, and while it was not in a manufacturing environment, I feel I have a good understanding of that process. In reading about rework, I confirmed time and temperature are critical to the reflow profile associated with removing and replacing components. These factors can impact long-term product quality. Hand soldering seemed risky, as I envisioned critical parts (medical, military) being reworked. Therefore, as part of my research, I visited an advanced rework equipment facility and operated one of its semiautomated rework systems (Figure 1). I was surprised at how intuitive and easy it was to use. Because I primarily deal with “automated” systems in the automated inspection world, my first thought was, Why not completely automate this process? I quickly realized, if fully automated rework is needed, that would indicate a serious manufacturing or design problem to be revisited. The ability to properly heat/cool the board/components in a reliable fashion, and accurately place the component, are the most critical factors to consider. The semiautomated system I saw could reduce and eliminate variables associated with time and temperature, thus creating a reliable reworked product.

Continuous improvement at rework appears a little different than I would have thought. While a barcode scanner may be used to call up defects, it is often manual paper systems or Excel spreadsheets that initiate rework station actions. My idealistic view of a closed-loop software connection and shop-floor systems is reserved for but a few high-volume production sites. That said, some rework operators and engineers do revisit their rework data to identify a Pareto of consistently reworked defects, and therefore attempt to solve the up-the-line problems.

It is through this effort that I have come to agree with a quote I found: “The rework and repair of printed circuit boards has never been more critical to the success of contract electronics manufacturers and OEMs than it is now.”1 Rework is a necessity. Process improvement, test and inspection will continue to improve yields and quality, but we will never achieve 100% yields. Therefore, it is critical to ensure all the right rework processes and equipment are in place to dictate long-term success. There is a great opportunity that lies ahead for inspection and test companies to incorporate rework into the test and inspection suite. As automation intensifies with AOI, AXI and ICT, and software systems that talk to one another to close the loop become available, including the rework process should be a priority.

Au.: Thank you to Robert Avila and Adrienne Gerard of Finetech for hosting my visit and for direction and consult during the preparation of this column.

References

1. Howard Rupprecht, Step 10: Rework & Repair, SMT, January 2001.

Stacy Kalisz Johnson is Americas marketing development manager at Agilent (agilent.com); stacy_johnson@agilent.com. 

The dwell time, flux and temperatures are main culprits.

Insufficient solder topside fillet occurs where the joint has not formed a good topside fillet. Per IPC acceptability standards, a total maximum of 25% depression, including both the primary solder destination and the secondary solder source sides, is permitted.

When troubleshooting, the primary process setup areas to check include:

• Conveyor speed too slow
• Time over preheat too long, causing the flux to be burned off.
• Dwell time too long, causing flux to be destroyed before exiting the wave.
• Conveyor speed too fast
• Dwell time too short/topside board temp too low.
• Topside board temp too high for flux, causing it to burn off before the wave.
• Insufficient flux, or flux is not active enough.
• Solder temperature too low, and it cools in the barrel before it reaches the topside.
• Wave height too low in one or both waves, so solder does not contact the board properly.

Other things to look for in the process include:

• Solder temperature too high or too low.
• Preheat too high or too low.
• Excess or insufficient flux blow-off.
• Board not seated properly.
• Contaminated flux or solder.
• Board pallet too hot.
• Solder wave height low.
• Flux SP GR too low.
• Conveyor speed high.
• Solder wave uneven.
• Flux SP GR too high.
• Flux applied unevenly or not making contact.

Other things to look for with the assembly:

• Board oxidized, warped or contaminated.
• Mask in hole.
• Laminate moisture.
• Poor plating in the hole.
• Hole and pad misregistration.
• Mask misregistration.
• Component contamination.

Other things to look for with the board design:

• Poor pallet design.
• Internal ground plane.
• Pad size mismatched.
• Large ground plane on component site.
• Lead-to-hole ratio too large or too small.
• Large ground plane on solder side.

Paul Lotosky is global director - customer technical support at Cookson Electronics (cooksonelectronics.com; plotosky@cooksonelectronics.com.

MEMS, HDI, embedded passives and LEDs present a sea change in the way boards are designed and built, and could shift the market back to the West.

One result of outsourcing is a loss of ability to understand new technologies on a basic level because they are not on the factory floor. From understanding comes opportunity. In response to IP and product piracy and the hypercompetitive marketplace in technology, many smart companies now involve only their closest partners in research and development programs. Those not a part of the group may never see new enabling technologies. This is what has happened to North America and Europe to a dangerous degree.

Today, in many cases, management, government, the military and even the scientific community do not understand the enabling technologies that can help spur a new economic renaissance. While focusing on nanotechnology, biotech or energy on a micro scale, we have lost the ability to make it simpler, more efficient and lower cost. This mistake has been repeated to the point it almost has become a maxim. Whether televisions, VCRs or cellphones, the business model in many cases has been technology development in Europe or North America, followed by exporting of manufacturing to lower cost regions. The West needs a healthy manufacturing sector to survive, and the interconnect is at the center of that capability.

Interconnect technology is not standing still. Amazing developments will help create the future (Figure 1). But we have to understand these opportunities and commit to seeing them through. Today, only a few factories in North America and Europe build substantial numbers of high-density interconnects. In 2008, one of the major drilling machine manufacturers counted approximately 150 laser drills, a critical tool for HDI, in North America. Globally, its census of the installed base is 3,600-plus units, primarily in Asia. A number of Asian manufacturers have 150-plus units in a single factory.

Today, HDI is a mainstream product, but only a small percentage of the circuit boards are built in North America. Markets include handheld devices, HDTV control boards, iPods and MP3 players, Bluetooth devices, high-end notebooks, GPS systems, automotive engine controls, cameras, digital watches, hard drives, and many other products. HDI is an enabling technology for smaller, lighter and faster electronics for military, aerospace and medical applications (Figure 2). The technology drivers are miniaturization, packaging, high frequency, I/O density and, in most cases, cost. Almost every inkjet printer cartridge in the world contains HDI. HDI circuit boards are, in fact, an extremely cost-effective technology, and hundreds of millions of units are produced each year.

North American demand for bare board HDI technology is in the billions of dollars, but the vast majority is imported. Recent data indicate that North American production of HDI boards was approximately $200 million, while known orders from a limited range of customers willing to share their data totaled over $1.1 billion (Table 1). Imports of products containing HDI boards are in the many billions of dollars. Most of this is in high-volume products.

However, HDI has not yet made the transition to many applications where the North American interconnect fabrication base feels it can compete successfully. The scale and cost of some technologies can appear daunting. The infrastructure that existed in the 1990s is now smaller. Today, these solutions are available on the open market. The hard work has been done. One of the critical reasons for success in Asia was the entire interconnect supply chain worked together to achieve common goals. Designers, OEMs, fabricators and assemblers co-developed efficient and lower-cost solutions, and understand how to use the technology effectively.

Embedded components. Coupled with the explosion in HDI use is the potential for embedded component technology. Embedded capacitance and resistance within the printed circuit board has been available for years, but had limited acceptance in North America. A major change in OEM philosophy toward embedded components occurred several years ago when the handheld manufacturers began a major push to reduce costs and increase functionality in a very limited form factor. Prototypes were manufactured in North America, but production went almost immediately to Asia. Yields climbed rapidly as designs were optimized. In some cases, functionality was placed on the chip (Figure 3). However, the seeds of a new idea had been planted. Today, embedded component technology has been growing along a path similar to HDI at its outset.

Manufacturing boards containing embedded actives and passives requires a high level of precision and absolute quality control. Once embedded, components typically cannot be repaired. It has to be done right the first time. While initial efforts in North America emphasized design rules and special materials, the Japanese approach uses either modified SMT components or die-attach devices. Chipsets including a CPU and memory are attached to the organic substrate using copper posts, microvias and copper plating. Some processes for passive devices use thin-film resistors; others use low-profile 0402, 0603, and 1005 resistors and capacitors.

The technical benefits include reduced I/O count, reduced component count, significantly improved interconnect reliability, vibration resistance, improved high-frequency transmission, reduced footprint and simplified routing (Figure 4). Heat dissipation can be enhanced by direct mounting on copper lands. Panel thickness also can be reduced considerably. In most cases, it is simply a better product.

Current applications include stacked memory, memory cards, BGAs, modules, portable electronics, sensors, fuel cells and automotive devices. Use in military and aerospace applications is growing as well because of the combination of advantages offered. One of the highest volume applications to date has been watches used by runners, which include GPS, distance, speed and pace information. In automotive and energy transmission applications, supercapacitors capable of discharging 50A at 4V are a game changer. One inch square and 100 µm thick, these components have the advantage of being embedded in very high volume, further driving this opportunity.

For the OEM, one of the significant advantages in using embedded components is IP protection. Hardware can be concealed and key design elements protected. Reverse engineering becomes more difficult by orders of magnitude, and security or encryption devices eventually can be embedded as well. In a world that runs on time to market, this simple benefit could be measured in the millions of dollars.

For the assembler, this means radically fewer joints to solder, and fewer opportunities for field failures.

In the long run, the real advantage is that radically new designs can be envisioned and enabled. The US Army Land Warrior Project envisioned biometrics, communications, medical capabilities and weapons systems integrated into a whole that projected the capabilities of the individual soldier far beyond today into the realm of science fiction. Much of the requisite technology already exists, but must be miniaturized, simplified and made more cost-effective. Information gathering and telematics will require simplified and rugged packaging solutions, and the opportunities in medical electronics alone are amazing. As 3G and 4G wireless technologies roll out, HDI/embedded will be integral to enable new features and applications. Apple, RIM, Nokia, Motorola and others have shown what can be done when video, wireless and other features are integrated in new and amazing ways.

Meso-MEMS/microfluidics. The latest initiatives in interconnect technology incorporate functions previously placed on a chip in some cases or completely new architectures based on those technologies. Microelectromechanical Systems (MEMS) have been in volume use for a number of years, primarily at the semiconductor level. The applications today include accelerometers used in airbags, MEMS gyroscopes used to detect yaw, car tire pressure sensors and many other applications. The DLP chip used in flat-panel televisions and many other applications consists of hundreds of thousands of micro mirrors that switch on and off. Microfluidic MEMS, such as pumps, valves, heating elements and channels, enable technologies such as the inkjet printers, as well as the 100-plus million printer cartridges sold each year. SEMI calculated the global market for MEMS in 2006 at over $40 billion.

MEMS technology is rapidly migrating to the interconnect for a variety of reasons. Inkjet printer cartridges, one of the first MEMS applications, developed at Hewlett Packard in 1979, use both HDI and MEMS because the technical and economic advantages make the most sense in the application. It is very high tech, but must be manufactured at very low cost. Meso MEMS, or those used on printed circuit substrates, originated at Motorola in the early 2000s (Figure 5). The ability to place MEMS on silicon is proven, but the penalty in increased packaging real estate on the chip and hermetic packaging requirements required in many applications becomes cost-prohibitive. Printed circuit boards today have crossed the 0.001" geometry line that semiconductors crossed in 1960, and thus many MEMS applications can be migrated to Meso-MEMS at much lower cost. A Meso-MEMS switch might require 0.001" to 0.005" line/space capability, and offer the advantage of much higher current capacity. Other Meso-MEMS opportunities include laboratory-on-a-chip (LOC), RF switches, valves and pumps.

LOC applies single or multiple laboratory processes onto the silicon. This is especially useful for analytical and medical applications. They offer significant advantages in portability, lower chemical costs and better process control in chemical and biochemical reactions. Analytical integrity is also enhanced because of the integration of functionality, isolation of samples, and precise volumes and metrics. Point-of-care applications will blossom as costs are reduced. Meso-MEMS is one tool to do so.

LEDs. A last niche application for printed circuit substrates is lighting. LED technology has already had a significant impact, from traffic lights to automotive brake lights to display technology. Energy savings of 90% or more, and lifetimes that are orders of magnitude longer than conventional incandescent or fluorescent lighting, make LEDs attractive. With close to 20% of North American energy demand consumed by lighting, the energy and economic impact is considerable. Even now, printed circuit substrates are being integrated into LED arrays. The application will accelerate as the availability of printable electroluminescent materials and organic LED (OLED) materials and solid-state lighting opportunities grow. The printed circuit board is an ideal low-cost substrate in many applications.

The combination of these technologies results in an active interconnect that goes far beyond the limitations of today’s conventions. When combined with optoelectronic components, RF designs or other technologies, it is obvious the printed circuit board will undergo a complete redefinition. The interconnect has become the nexus and cortex of technology. The trend is toward high-mix/low-volume and flexible response. Implementing HDI/embedded requires significant investment and a change in the way the factory floor is run. The benefits, however, quickly will be seen in more stable business relationships, technology partnerships, and significantly improved margins and yields.

Matthew Holzmann is president of Christopher Associates (christopherweb.com); matt.holzmann@christopherweb.com.