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This article originally appeared on EECatalog.com.

By Venetia Espinoza, BrightVolt

Are the power solutions the IoT needs arriving quickly enough?

The massive game-changing potential of the Internet of Things (IoT) connected devices has been limited by a lack of effective power solutions. The solid-state thin film battery market is forecasted to reach $1.3 bil­lion worldwide by 2021 as published by Custom Market Insights. Fueling this growth is the rise of IoT—wear­ables, medical devices and sensors. Traditional battery technologies simply cannot provide the new features and designs that these new applications demand.

However, arriving on the market are thin-film, flexible batteries which are ultra-thin, flexible, rollable, stretch­able and can withstand high temperatures.

Many applications are still emerging, and their require­ments are evolving fast. Because target specs are also very diverse, each with unique requirements for power, thinness, cost, safety, shelf life, reliability, and flex­ibility, a customized power source makes sense.

BrightVolt is one company tackling the demand for small powered solutions.

Figure 1: Traditional battery technologies are giving way to new designs, which can reduce design complexity. (Courtesy BrightVolt)

Low power/long battery life—As IoT infrastructure becomes ubiquitous, many use-cases require designing and building low power and small form factor batteries, both primary and rechargeable. BrightVolt’s Flexion™ batteries have 3.0V, multiple capacity options such as 10, 14, 20, 25mAh and varied tab con­figurations such as extended tab, terminal support, terminal support with ACF. They also have attachment options such as ultrasonic welding, soldering, conductive epoxy and conductive film and a shelf life of 3-5+ years.

Customized—Battery designs are available that are as thin as 0.37mm. For example, BrightVolt Flexion batteries were designed to operate continuously over a wide temperature range (-10 ºC to +60 ºC). They utilize a patented solid polymer electrolyte and contain no volatile liquids or gelling agents. Self-connecting battery terminals using anisotropic conductive film. BrightVolt can custom-build the size, shape, power, capacity, tab configurations and attachment options that are needed for these diverse requirements.

Scalable Manufacturing—BrightVolt has already shipped millions of units. Scalability is our key differentiator. We can take a solution from prototype to full production and anything in between. Our enduring quality, durability, and built-in intelligence is what makes us the best choice for custom product designs.

Safe—It is now possible to find batteries that are non-toxic, non-corrosive and environ­mentally friendly. It’s also important to choose an Inherently safe design that reduces the need for additional battery safety circuitry. Polymer matrix electrolyte provides outstanding thermal stability with no volatile liquids or gels.

Medical Miracles and Thin Batteries

Nanotechnology itself dates back to the 1980s, when U.S. engineer Eric Drexler coined it. Today, nanotechnology and tiny batteries are changing the medical device industry.

Applicable medical uses include the ability to use small form batteries to power the circuitry associated wit skin-based monitoring devices that can detect the glucose levels, for example. Trans­dermal drug delivery and patches could change how injectable drugs are delivered in a more effective time-released manner through a battery-powered patch.

Additionally, the combination of a nanosensor used in conjunction with a smartphone could be used to track auto­immune diseases and cancer. It could also be an effective screening tool for rejection in patients with organ transplants.

Sensors, Smart Packaging and the IoT

It is anticipated that the temperature monitoring market will reach over $3.2 billion by 2020. Smart sensor labels answer the needs for numerous indus­tries, particularly perishable goods. These printed electronics devices and labeling enable the IoT to reduce waste and improve consumer safety.

This technology allows pharmaceutical companies to keep temperature-sensitive products safe and effective, while pre­venting the unnecessary ruin of usable products. Retailers who use temperature-monitoring labels during shipment of produce and other food products as well as cosmetics and off-the-shelf healthcare items will have immediate insight with regards to both shelf life and food safety.

Some of the most ubiquitous wearables are fitness trackers like FitBit and Jaw­bone that hit the market like wildfire in 2013. 1 in 5 Americans today wear this technology to track their activity levels, sleep and more. Wearables will continue to evolve in size, usability, form factors and diverse power needs.

Assisted living and eldercare is another compelling and demanding wearable technology market. Wearable sensors for this market pose massive potential in generating big data for IoT, with a great applicability to biomedicine and ‘ambient assisted living’ (AAL). ‘Ambient intelligence’ in eldercare is being sensi­tive and responsive to the presence of people. Recent advancements in several technological areas have helped the vision of AAL to become a reality. These tech­nologies include of course smart homes, assistive robotics, and, in small form: e-textile, mobile and wearable sensors.

Another significant advancement is detecting common medical issues such as sleep apnea, which used to require an uncomfortable in-clinic sleep study. No more. Today, a patient can wear a device overnight in the privacy of their own home and send the results off to their physician. Other exciting uses include trackers in clothing, interactive toys, games and more.

Embedding Security

Target’s $10 million 2013 class action data breach lawsuit and privacy issue hammered home just how devastating security fraud really is. Since that time, many credit cards are now embedded with an EMV chip but there’s an even better solution emerging. Not only will a small form battery the size of a postage stamp power these new cards, a com­puter chip randomizes the code number about every hour, adding to its security. This renders the card useless to anyone who has written down your card number, expiration date and code. This applica­tion will effectively eliminate ‘card not present’ fraud. Other ultra-thin battery uses in a credit card could allow for a tiny screen on your card itself that displays your balance.

When Apple launched its biometric ID fingerprint reader on its iPhone 5S, many people adjusted quickly to the convenience of the fingerprint password. Building on that same technology, travel documents including drivers’ licenses and passports, as well as vital health information, can be included in one ultra-thin battery-powered, pocket-sized card that fits in your wallet.

Conclusion

By assessing the considerations outlined in this article, a product designer can effectively achieve a small-form factor product able to reliably operate with the right battery. Custom batteries can eliminate design complexities and opti­mize battery use for many applications.

About the Author

Venetia Espinoza is in charge of market­ing at BrightVolt, a worldwide leader in the design, development and scale manufacturing of thin film batteries. She holds more than 25 years of marketing and product experience with premier technology companies. She also served as Vice President and General Manager of Softcard, a joint venture established by industry giants Verizon, AT&T and T-Mobile. She holds an MBA and BS de­gree in Industrial Engineering.

By David W. Price, Douglas G. Sutherland and Kara L. Sherman

Author’s Note: The Process Watch series explores key concepts about process control—defect inspection and metrology—for the semiconductor industry. Following the previous installments, which explored the 10 fundamental truths of process control, this new series of articles highlights additional trends in process control, including successful implementation strategies and the benefits for IC manufacturing. For this article, we are pleased to include insights from our guest author, Kara Sherman.

As we celebrate Earth Day 2016, we commend the efforts of companies who have found ways to reduce their environmental impact. In the semiconductor industry, fabs have been building Leadership in Energy and Environmental Design (LEED)-certified buildings [1] as part of new fab construction and are working with suppliers to directly reduce the resources used in fabs on a daily basis.

As IC manufacturers look for more creative ways to reduce environmental impact, they are turning to advanced process control solutions to reduce scrap and rework, thereby reducing fab resource consumption. Specifically, fabs are upgrading process control solutions to be more capable and adding additional process control steps; both actions reduce scrap and net resource consumption per good die out (Figure 1).

Figure 1. The basic equation for improving a fab’s environmental performance includes reducing resource use and increasing yield. Capable process control solutions help fabs do both by identifying process issues early thereby reducing scrap and rework.

Figure 1. The basic equation for improving a fab’s environmental performance includes reducing resource use and increasing yield. Capable process control solutions help fabs do both by identifying process issues early thereby reducing scrap and rework.

Improved process control performance

Process control is used to identify manufacturing excursions, providing the data necessary for IC engineers to make production wafer dispositioning decisions and to take the corrective actions required to fix process issues.

For example, if after-develop inspection (ADI) data indicate a high number of bridging defects on patterned wafers following a lithography patterning step, the lithography engineer can take several corrective actions. In addition to sending the affected wafers back through the litho cell for rework, the engineer will stop production through the litho cell to fix the underlying process issue causing the yield-critical bridging defects. This quick corrective action limits the amount of material impacted and potentially scrapped.

To be effective, however, the quality of the process control measurement is critical. If an inspection or metrology tool has a lower capture rate or higher total measurement uncertainty (TMU), it can erroneously flag an excursion (false alarm), sending wafers for unnecessary rework, causing additional consumption of energy and chemicals and production of additional waste. Alternatively, if the measurement fails to identify a true process excursion, the yield of the product is negatively impacted and more dies are scrapped—again, resulting in less desirable environmental performance.

The example shown in Figure 2 examines the environmental impact of the process control data produced by two different metrology tools in the lithography cell. By implementing a higher quality metrology tool, the quality of the process control data is improved and the lithography engineers are able to make better process decisions resulting in a 0.1 percent reduction in unnecessary rework in the litho cell. This reduced rework results in a savings of approximately 0.5 million kWh of power and 2.4 million liters of water for a 100k WSPM fab—and a proportional percentage reduction in the amount of resist and clean chemicals consumed.

Figure 2. Higher quality process control tools produce better process control data within the lithography cell, enabling a 0.1 percent reduction in unnecessary rework that results in better environmental performance.

Figure 2. Higher quality process control tools produce better process control data within the lithography cell, enabling a 0.1 percent reduction in unnecessary rework that results in better environmental performance.

As a result of obtaining increased yield and reduced scrap, many fabs have upgraded the capability of their process control systems. To drive further improvements in environmental performance, fabs can benefit from utilizing the data generated by these capable process control systems in new ways.

Traditionally, the data generated by metrology systems have been utilized in feedback loops. For example, advanced overlay metrology systems identify patterning errors and feed information back to the lithography module and scanner to improve the patterning of future lots. These feedback loops have been developed and optimized for many design nodes. However, it can also be useful to feed forward (Figure 3) the metrology data to one or more of the upcoming processing steps [2]. By adjusting the processing system to account for known variations of an upcoming lot, errors that could result in wafer scrap are reduced.

For example, patterned wafer geometry measurement systems can measure wafer shape after processes such as etch and CMP and the resulting data can be fed back to help improve these processes. But the resulting wafer shape data can also be fed forward to the scanner to improve patterning [3-5]. Likewise, reticle registration metrology data can be used to monitor the outgoing quality of reticles from the mask shop, but it can also be fed forward to the scanner to help reduce reticle-related sources of patterning errors. Utilizing an intelligent combination of feedforward and feedback control loops, in conjunction with fab-wide, comprehensive metrology measurements, can help fabs reduce variation and ultimately obtain better processing results, helping reduce rework and scrap.

Fig 3

Figure 3. Multiple data loops to help optimize fab-wide processes. Existing feedback loops (blue) have existed for several design nodes and detect and compensate for process variations. New, optimized feedback loops (green) provide earlier detection of process changes. Innovative feed forward loops (orange) utilize metrology systems to measure variations at the source, then feed that data forward to subsequent process steps.

Earlier excursion detection reduces waste

Fabs are also reducing process excursions by adding process control steps. Figure 4 shows two examples of deploying an inspection tool in a production fab. In the first case (left), inspection points are set such that a lot is inspected at the beginning and end of a module, with four process steps in between. If a process excursion that results in yield loss occurs immediately after the first inspection, the wafers will undergo multiple processing steps, and many lots will be mis-processed before the excursion is detected. In the second case (right), inspection points are set with just two process steps in between. The process excursion occurring after the first inspection point is detected two days sooner, resulting in much faster time-to-corrective action and significantly less yield loss and material wasted.

Furthermore, in Case 1, the process tools at four process steps must be taken off-line; in Case 2, only half as many process tools must be taken offline. This two-day delta in detection of a process excursion in a 100k WSPM fab with a 10 percent yield impact results in a savings of approximately 0.3 million kWh of power, 3.7K liters of water and 3500 kg of waste. While these environmental benefits were obtained by sampling more process steps, earlier excursion detection and improved environmental performance can also be obtained by sampling more sites on the wafer, sampling more wafers per lot, or sampling more lots. When a careful analysis of the risks and associated costs of yield loss is balanced with the costs of additional sampling, an optimal sampling strategy has been attained [6-7].

Figure 4. Adding an additional inspection point to the line will reduce the material at risk should an excursion occur after the first process step.

Figure 4. Adding an additional inspection point to the line will reduce the material at risk should an excursion occur after the first process step.

Conclusion

As semiconductor manufacturers focus more on their environmental performance, yield management serves as a critical tool to help reduce a fab’s environmental impact. Fabs can obtain several environmental benefits by implementing higher quality process control tools, combinations of feedback and feedforward control loops, optimal process control sampling, and faster cycles of learning. A comprehensive process control solution not only helps IC manufacturers improve yield, but also reduces scrap and rework, reducing the fab’s overall impact on the environment.

References

  1. Examples:
    1. https://newsroom.intel.com/news-releases/intels-arizona-campus-takes-the-leed/
    2. http://www.tsmc.com/english/csr/green_building.htm
    3. http://www.ti.com/corp/docs/manufacturing/RFABfactsheet.pdf
    4. http://www.globalfoundries.com/about/vision-mission-values/responsibility/environmental-sustainability-employee-health-and-safety
  1. Moyer, “Feed It Forward (And Back),” Electronic Engineering Journal, September 2014. http://www.eejournal.com/archives/articles/20140915-klat5d/
  2. Lee et al, “Improvement of Depth of Focus Control using Wafer Geometry,” Proc. of SPIE, Vol. 9424, 942428, 2015.
  3. Tran et al, “Process Induced Wafer Geometry Impact on Center and Edge Lithography Performance for Sub 2X nm Nodes,” 26th Annual SEMI Advanced Semiconductor Manufacturing Conference, 2015.
  4. Morgenfeld et al, “Monitoring process-induced focus errors using high resolution flatness metrology,” 26th Annual SEMI Advanced Semiconductor Manufacturing Conference, 2015.
  5. “Process Watch: Sampling Matters,” Semiconductor Manufacturing and Design, September 2014.
  6. “Process Watch: Fab Managers Don’t Like Surprises,” Solid State Technology, December 2014.
  7. “Reducing Environmental Impact with Yield Management,” Chip Design, July 2012.

About the Authors:

Dr. David W. Price, Dr. Douglas Sutherland, and Ms. Kara L. Sherman are Senior Director, Principal Scientist, and Director, respectively, at KLA-Tencor Corp. Over the last 10 years, this team has worked directly with more than 50 semiconductor IC manufacturers to help them optimize their overall inspection strategy to achieve the lowest total cost. This series of articles attempts to summarize some of the universal lessons they have observed through these engagements

Overall demand for optoelectronics, sensors, actuators, and discrete semiconductors softened in 2015 as the fragile global economy weakened, but these market segments are expected to stabilize in 2016 and gradually return to more normal growth rates in the second half of this decade, according to IC Insights’ new 2016 O-S-D Report—A Market Analysis and Forecast for Optoelectronics, Sensors/Actuators, and Discretes.  The 360-page report shows combined O-S-D sales growing 5% in 2016 to a new record-high $70.2 billion, after increasing just 3% in 2015 to the current annual peak of $66.6 billion.  O-S-D revenues accounted for nearly 19% of the semiconductor industry’s $353.7 billion sales total in 2015 versus about 81% coming from ICs (Figure 1), according to IC Insights’ newly released report.

osd market share

 

Total O-S-D revenues continued to outgrow the larger integrated circuit market, which dropped 1% last year to $291.5 billion, primarily because of the weak global economy and a 3% decline in memory IC sales.    O-S-D’s share of 2015 semiconductor sales was the highest it has been since 1988.  IC Insights expects the O-S-D marketplace to account for 20.0% of total semiconductor sales in 2020.

On the strength of optoelectronics and sensor products—including CMOS image sensors, high-brightness light-emitting diodes (LEDs), and devices built with microelectromechanical systems (MEMS) technology—total O-S-D sales have outpaced the compound annual growth rate (CAGR) of ICs since the mid-1990s.  IC Insights’ new report shows this trend continuing in the next five years.  The 2016 O-S-D Report says modest improvements in the global economy, steady increases in electronic systems production, and new end-use applications—such as wearable systems and connections to the Internet of Things (IoT)—are expected to collectively lift the three O-S-D market segments by a CAGR of 6.5% between 2015 and 2020 compared to a projected 4.9% annual growth rate for IC sales in the second half of this decade.

During 2015, the O-S-D marketplace was a mixed bag of double-digit growth in most optoelectronics products and sales declines in discretes and a number of large sensor categories.  Optoelectronics sales grew 11% to a record-high $35.2 billion in 2015 while the discretes market suffered its worst decline since the 2009 semiconductor downturn year, falling nearly 8% to $21.2 billion, says the new O-S-D Report.  The sensors/actuators market increased about 4% in 2015 to a record-high $10.2 billion, with steep price erosion in accelerometers, gyroscope devices, and magnetic-field sensors dragging down overall growth in this semiconductor segment, according to the report.  In 2016, optoelectronics sales are expected to increase 9% to $38.2 billion, while sensors/actuators revenues are forecast to rise again by 4% to $10.6 billion, and the commodity-filled discretes market is projected to grow just 1% this year.  Between 2015 and 2020, all three O-S-D market segments are forecast to expand by more normal annual dollar-sales growth rates—with optoelectronics rising by a CAGR of 8.3%, sensors/actuators increasing at a rate of 5.6%, and discretes being up by a CAGR of 3.5% (Figure 2).

osd return to normal

 

Since 2000, we have entered the age of sensing and interacting with the wide diffusion of MEMS and sensors that give us a better, safer perception of our environment. MEMS have grown in volume to be almost a 15 billion units market today. And analysts believe that this market will double to almost 30 billion by 2020, in less than 5 years, according to the Status of the MEMS Industry, Yole Développement, May 2015.

Claire Troadec, MEMS & Semiconductor Manufacturing Analyst from Yole Développement (Yole), the “More than Moore” market research and strategy consulting proposes you to learn more about the MEMS & sensors challenges and identify the related opportunities for the next decade. So what can we expect?

Since its early beginning, MEMS technology has been considered as a “transfer function” technology: taking existing products such as Hg tilt sensors, syringe, galvanometric mirror and transforming them in IMU , micro-needles, micro-mirrors. The interest of MEMS relies in the miniaturization and lower cost manufacturing brought by a semiconductor technology.

Today the MEMS & Sensors industry is transitioning towards 3 main hubs: the inertial hub (a closed package hub), the optical hub and the environmental hub (open package hubs)

Looking closely at the inertial hub, complete integration has been achieved at sensor level. The miniaturization race is still ongoing to lower the sensor cost and developments are focusing on advanced packaging technologies (e.g. TSV, WLP) and power consumption reduction. Major developments occur at software level to achieve sensor fusion and get precise data acquisition, precise tracking within the environment. Hence the inertial Bill of Materials within a smartphone today is around US$1.

This is nothing compared to the US$10 spent for the optical hub within the same smartphone: imaging is highly valued by the end customer. This is part of our “human” nature, where vision represent around 83% of our external world perception .

And what about the environmental hub? At Yole, we do believe that the environmental hub is an interesting way for the MEMS industry to gain value. Therefore, particles, gas detection are real market pull applications which would make sense to be integrated in a smartphone. Some more integration could also be achieved by combining pressure and microphone for example. Of course, this increased integration is not an easy task but represents real market opportunities. Today’s environmental sensors’ Bill of Materials in a smartphone is around US$0.70 and could represent US$1.50 tomorrow with this increased integration path.

The MEMS Market is observing a strong paradox today

Increasing volumes driven by the consumer wave (more and more smartphones sold and more and more sensors integrated in smartphone) leading to sensor die size reduction to answer the strong price pressure dictated by the consumer market. But this affect sensors margins, which shrink if the process is not re-tuned to gain on margin again. Overall resulting in a stable or declining market in terms of value!

Thus is the MEMS industry digging its own grave with this commoditization paradox? How to exit from this scenario?

mems virtuous cycle

Well, one might take a step back and look at what the CMOS Image sensor industry has achieved. Driven by the self-love or narcissism of human kind, the front cameras of our smartphones have increased in resolution for us to achieve better quality images of “selfies”: Hence the front camera resolution has been increased by a factor 4 in 4 years, thanks to increased number of pixels and thus sensor die size, leading inevitably to higher sensor prices!

What can we learn from this story and apply to the MEMS industry to gain value?
More complexity at system level: drive for better accuracy/precise tracking and features, meaning:
•  Sensor fusion
•  More integration: Pressure + microphone for example
•  Improved environment tracking: particles and gas sensing

MEMS markets challenges are thus evolving
Power consumption is becoming a major trend while mobiles, tablets, wearables have to survive for long periods on battery while interacting with the environment (voice calls, Wi-Fi, Bluetooth, GPS , sensors …).

Sensor fusion, software and added features are the current battleground of the hubs integration path.
Finally the user case is definitely mandatory! The idea is to start with applications, and work downwards to the chips needed to support them. This will be easier for a system maker than a pure sensor player who is further away on the supply chain and thus further away from his final end user needs!

In brief a new virtuous cycle is needed for the MEMS industry to gain value and stop being limited by shrinking prices and margins.

ILLUS_MEMSVirtuousCycle_YOLE_March2016_2

Yole’s analysts highlight the MEMS market evolution and technology trends within the report Status of the MEMS Industry, yearly updated (2015 edition available on i-micronews.com – 2016 version to be released soon). Moreover make sure you will meet our analysts and debate with them at

   •  MEMS Engineer Forum (May 11&12, 2016 – Tokyo, Japan), within the MEMS trends worldwide session. Yole’s presentation is entitled “MEMS & Sensors for Smart Cities” and takes place on May 11 at 11:00 AM. Speaker: Claire Troadec, Technology & Market Analyst, MEMS & Semiconductor Manufacturing, Yole Développement
•  2016 Sensors Expo & Conference (June 21 – 23, 2016 – McEnery Convention Center, San Jose, CA), Pre-Conference Symposium 3 entitled “IoT 2.0 – Sensor Innovation Moves From “Smart” to “Intelligent”” on June 21 from 9:00 AM to 5:00 PM. Speaker: Guillaume Girardin, Technology & Market Analysts, MEMS & Sensors, Yole Développement.

Luminaries from the micro-electromechanical systems (MEMS) industry are spurring entrepreneurship by hosting the first “MEMS Shark Pup Tank” at Hilton Head 2016 Workshop, an interactive science and technology conference on solid-state sensors, actuators and microsystems, June 5-9, 2016 in Hilton Head, SC.

“Bringing a new MEMS device to market can feel like a Herculean task as there are so many moving parts to the process,” said Jessica Gomez, founder and CEO of Rogue Valley Microdevices. “Given this reality, a highly accomplished group of MEMS industry experts aim to lower the barrier to entry for entrepreneurs who want to introduce MEMS-based products that could influence the global economy by 2025. MEMS Shark Pup Tank is the product of their combined vision, and we are thrilled to play a part by contributing foundry services to the event’s champion.”

The MEMS Shark Pup Tank Champion will receive:

  • Product development/strategy consulting and patent consulting time by industry experts:
  • $10,000 in MEMS foundry services from Rogue Valley Microdevices, a full-service precision MEMS foundry
  • 6 months license of MEMS Pro software from softMEMS, a leading developer of MEMS software design tools
  • One year membership in MEMS & Sensors Industry Group, the trade association advancing MEMS and sensors across global markets

The MEMS Shark Pup Tank runner-up will also receive an award package.

Submission Deadline: March 31, 2016

Teams must submit their business plan by March 31, 2016 by visiting: http://www.hiltonhead2016.org/events/shark.html

By Douglas G. Sutherland and David W. Price

Author’s Note: This is the last in a series of 10 installments that explore certain fundamental truths about process control—defect inspection and metrology—for the semiconductor industry. Each article introduces one of the 10 fundamental truths and highlights its implications. Within this article we will use the term inspection to imply either defect inspection or a parametric measurement such as film thickness or critical dimension (CD).

In the eighth installment1 in this series, “The Tyranny of Numbers,” we discussed the trend of increasing process steps—the number of steps is expected to double between the 20nm and 10nm nodes—and the impact that those additional steps will have on final yield. In addition to impacting yield, the increased complexity of the process flow will also increase production costs and cycle time. As these trends unfold, managing costs and cycle time will become increasingly important to fab operations.

The tenth fundamental truth of process control for the semiconductor IC industry is:

Adding Process Control Reduces Production Costs and Cycle Time

Instrumental to having an efficient, low-cost fab is the ability to collect meaningful information about the process in a timely fashion. Process control tools (metrology and inspection) are the eyes and ears of the fab in that they provide insight into what’s working and what’s not: they are an investment in “process information.” In a 2007 paper2 the National Institute of Standards and Technology (NIST) estimated that the average return on investment for metrology alone was 300 percent.

Previous articles in this series have illustrated how process control can reduce costs by reducing the scrap and raw material costs associated with lost yield and reliability3 failures. Similarly, improving yield reduces the environmental footprint of fab operations per good die out.4 In this article, we will examine two other elements of cost reduction and factory efficiency enabled by process control:

  1. Process equipment re-use from node-to-node
  2. Improved net cycle time

Equipment Re-Use

The single biggest component of cost in a modern fab is capital depreciation. It can vary from company to company, but typically wafer fab capital equipment is depreciated at 20 percent per year over the course of five years. If you can extend the life of a piece of equipment beyond the point where it is fully depreciated you are essentially getting that tool for free. If you can find a way to re-use an entire group of process tools (scanners, etchers, etc.) the savings could easily be measured in tens or even hundreds of millions of dollars.

Ultimately, a process tool must meet the technical specifications that are demanded by the manufacturing process in which it is used. However, in cases where the tool’s capability is marginal, its lifetime can be extended by closer monitoring—using existing metrology or inspection tools to keep the tool operating within the required process specifications. Performing more frequent process tool qualifications can help improve matching and ensure that a tool does not drift out of spec. For stable feed-back and feed-forward schemes, having more in-line inspections provides better averaging and allows for better control of the actual process. In these situations, process control is helping to extend the life of existing process tools—adding process control in this context can actually save money.

The Process Capability Index (Cpk) is a metric that measures how well the natural variation of a process fits within the spec limits. For a centered process with a symmetric distribution the Cpk is given by equation 1,

Cpk = (USL – LSL) / 6σ                             Eq. 1

where USL and LSL are the upper and lower spec limits respectively and s is the standard deviation of the process. If the Cpk value is greater than one, the process is considered capable. Cpk values less than one indicate that the process is not capable.

Consider an etch process step where the Cpk of the CD measurement is exactly equal to one (i.e., the step is marginally capable in that the upper and lower spec limits are both three standard deviations from the mean). The marginal capability could be the fault of the previous photo step, the etch step or both. Either way it is an expensive proposition to upgrade either tool set to improve the Cpk—the capability —of the process.

Often the capability of the process can be improved by implementing a data feed-forward scheme—using additional metrology to fully characterize the process at one step (e.g., photo) and then feeding that information forward to adjust parameters at etch to effectively customize the process conditions for each lot or wafer. Figure 1 below shows an example Statistical Process Control (SPC) chart of the after-etch CD with and without feed-forward.

Figure 1. Left: SPC Chart of etch CD without feed forward (Cpk=1.0). Right: SPC Chart of etch CD with feed forward (Cpk=1.3)

Figure 1. Left: SPC Chart of etch CD without feed forward (Cpk=1.0). Right: SPC Chart of etch CD with feed forward (Cpk=1.3)

Feed-back and feed-forward schemes can be used to extend the useful lifetime of process tools by effectively increasing the process window in which they operate. CD measurements that are slightly off target at photo can be brought back on target by using that information to adjust the etch bias at the etch process step. 

Cycle Time

Cycle time is another very important production metric. We will give a more detailed account of cycle time in an upcoming paper but would like to touch briefly on the counter-intuitive relationship between cycle time and process control.

Any source of variability that prevents lots from moving through the fab in lock-step fashion will increase the cycle time. Adding inspection steps will add cycle time to those lots that get inspected but due to sampling (not every lot gets inspected) it will have a much smaller impact on the average. When an excursion does occur, comparatively few process tools will have to be put down (because the inspection points are closer together) and the module owner will be able to isolate the problem much sooner. The total disruption to the fab (the variability) will be reduced and the cycle time of all lots will be improved. This counter-intuitive concept has been demonstrated by several fabs that have both added inspection steps and reduced cycle time simultaneously.

To summarize, adding process control steps contribute to fab efficiency on several levels (figure 2): increasing baseline yield, extending the useful life of existing process tools, limiting the duration of excursions, and reducing cycle time.

Figure 2. The cascading benefits of process control.

Figure 2. The cascading benefits of process control.

As we conclude this series on the 10 fundamental truths of process control1,3,5-11, we thank you for reading. We hope that these articles have provided deeper insight into the value of process control and the base knowledge for successful implementation of process control in IC fabrication. We look forward to exploring additional aspects of process control in future Process Watch articles throughout the coming months.

References:

About the authors:

Dr. David W. Price is a Senior Director at KLA-Tencor Corp. Dr. Douglas Sutherland is a Principal Scientist at KLA-Tencor Corp. Over the last 10 years, Drs. Price and Sutherland have worked directly with more than 50 semiconductor IC manufacturers to help them optimize their overall inspection strategy to achieve the lowest total cost. This series of articles attempts to summarize some of the universal lessons they have observed through these engagements.

Nanoelectronics research center, imec, and digital research and incubation center, iMinds, today announced that its respective board of directors have approved the intention to merge the research centers. Using the imec name, the combined entities intend to create a high-tech research center for the digital economy. The transaction is expected to be completed by the end of 2016, with the united organization staged to bring added value to existing partners while further strengthening Flanders’ authority as a technology epicenter and region focused on creating a sustainable digital future.

iMinds will be integrated as an additional business unit within imec, resulting in a new research center that will fuse the technology and systems expertise of more than 2,500 imec researchers worldwide with the digital competencies of some 1,000 iMinds researchers representing nearly 50 nationalities. The additions of iMinds’ flagship open innovation research model -ICON- (in which academic researchers and industry partners jointly develop solutions for specific market needs), iStart entrepreneurship program (supporting start-up businesses), and Living Labs will strengthen the unique capabilities and assets of imec as a research and development center.

Imec has been a global leader in the domain of nanoelectronics for more than 30 years, and has innovated applications in smart systems for the Internet of Things (IoT), Internet of Health, and Internet of Power. It has built an extensive and worldwide partner network, as well as in Flanders, and has generated successful spin-offs. iMinds’ activities span research domains such as the IoT, digital privacy and security, and the conversion of raw data into knowledge. Its software expertise is widely renowned and its entrepreneurship activities in Flanders are first-rate.

“The proliferation of the Internet of Everything has created a need for solutions that integrate both hardware and software. Such innovative products that optimally serve tomorrow’s digital economy can only be developed through intense interaction between both worlds. There are infinite opportunities in domains such as sustainable healthcare, smart cities, smart manufacturing, smart finances, smart mobility, smart grids, or in short, smart everything. Research centers such as imec, with its widely acclaimed hardware expertise, and iMinds, an expert in software and ICT applications, are uniquely positioned to bring these concepts to life,” stated Luc Van den hove, president and CEO of imec. “Furthermore, iMinds is widely recognized for its business incubation programs and open access to SMEs, and, this merger provides us with a unique opportunity to jointly reach out to the Flemish industry and further elevate Smart Flanders on the global map.”

“Flanders faces the enormous challenge of realizing a successful transition towards tomorrow’s digital society; a transition that must happen quickly, considering the urgency to reinforce Flanders’ industrial position,” commented Danny Goderis, CEO of iMinds. “The merger between imec and iMinds is Flanders’ answer to this rapidly accelerating digitization trend. We have a clear ambition to pair more than 3,500 top researchers across 70 countries with an ecosystem of Flemish companies and start-ups, thereby significantly increasing our economic and societal impact. Together, we can help Flanders boost its competitiveness and claim a strong international position.”

Now that the intention to merge has been approved, the merger protocol will be developed and the integration process of imec and iMinds will be initiated immediately. The current iMinds activities will constitute a third pillar next to imec’s units. iMinds will remain headquartered in Ghent with its researchers spread across the Flemish universities. The ambition is to operate as one organization by the end of 2016.

Flemish Minister of Innovation Philippe Muyters welcomes the fact that iMinds and imec join forces: “Thanks to their pioneering work in their respective fields, they have put themselves on the world map. When they were founded, the line between hardware and software was still very clear. Today, and especially in the future, this line is increasingly blurring – with technology, systems and applications being developed in close conjunction. The merger anticipates this trend and creates a high-tech research center for the digital economy that keeps Flanders on the world map. The gradual integration of both research centers, and the agreement to preserve their respective strengths and uniqueness, will make for a bright future.”

The popularity of Apple’s iPhone 6S and other products is boosting the microelectromechanical-systems (MEMS) microphones market to a compound annual growth rate (CAGR) of 11 percent from 2015 to 2019. The market is forecast to reach 5.8 billion units, with $1.3 billion in revenue, in 2019. Apple, which shifted from three MEMS microphones in the iPhone 6 line to four in the iPhone 6S line, will purchase more than one billion MEMS microphones in 2016 for the iPhone, according to IHS Inc. (NYSE: IHS).

“Prior to Apple, Microsoft and Motorola had already introduced some smartphones with four MEMS microphones, but in lower volumes,” said Marwan Boustany, senior analyst for MEMS and Sensors for IHS Technology. “Following Apple’s lead, additional manufacturers are expected to start including between two and four MEMS microphones in mobile handsets.”

Source: IHS

 

Apple is expected to purchase more MEMS microphones than Samsung Electronics, Xiaomi and Huawei combined in 2016. When counting the MEMS microphones used for the iPad, and for the earbuds sold with Apple’s iPhone, Apple Watch and Macbook notebooks, Apple accounted for a third of the total consumption of MEMS microphones in 2015.

The move to three or four microphones is currently driven by hands-free calling and voice commands for Siri, Google Now, Cortana and other apps, which are becoming an increasingly important means of interaction between consumers and their smartphones. Additional MEMS microphones are also added on the back of the phone for richer audio fidelity in video recording, noise cancellation and better call and recording performance.

“It will be harder for manufacturers to justify a move to five microphones in the coming years, unless clear and potentially popular use cases are identified,” Boustany said. “So far, Motorola’s Droid Turbo is the only handset with five MEMS microphones to become widely available.”

Knowles remains the market leader in MEMS microphone shipments and revenue, but the company’s share is eroding. Goertek, STMicroelectronics and AAC have recently made great gains in the market, selling to Apple and other companies, according to the IHS MEMS & Sensors for Consumer and Mobile Intelligence Service.

Along with the fast development of modern information technology, charge-based memories, such as DRAM and flash memory, are being aggressively scaled down to meet the current trend of small size devices. A memory device with high density, faster speed, and low power consumption is desired to satisfy Moore’s law in the next few decades. Among the candidates of next-generation memory devices, cross-bar-shaped non-volatile resistive memory (memristor) is one of the most attractive solutions for its non-volatility, faster access speed, ultra-high density and easier fabrication process.

Conventional memristors are usually fabricated through conventional optical, imprint, and e-beam lithographic approaches. However, to meet Moore’s law, the assembly of memristors comprised of 1-dimensional (1D) nanowires must be demonstrated to achieve cell dimensions beyond limit of state-of-art lithographic techniques, thus allowing one to fully exploit the scaling potential of high density memory array.

Prof. Tae-Woo Lee (Dept. of Materials Science and Engineering) and his research team have developed a rapid printing technology for high density and scalable memristor array composed of cross-bar-shaped metal nanowires. The research team, which consists of Prof. Tae-Woo Lee, research professor Wentao Xu, and doctoral student Yeongjun Lee at POSTECH, Korea, published their findings in Advanced Materials.

They applied an emerging technique, electrohydrohynamic nanowire printing (e-NW printing), which directly prints highly-aligned nanowire array on a large scale into the fabrication of microminiature memristors, with cross-bar-shaped conductive Cu nanowires jointed with a nanometer-scale CuxO layer. The metal-oxide-metal structure resistive memory device exhibited excellent electrical performance with reproducible resistive switching behavior.

This simple and fast fabrication process avoids conventional vacuum techniques to significantly reduce the industrial-production cost and time. This method paved the way to the future down-scaling of electronic circuits, since 1D conductors represent a logical way to extreme scaling of data processing devices in the single-digit nanometer scale.

They also succeeded in printing memristor array with various shapes, such as parallel lines with adjustable pitch, grids, and waves which can offer a future stretchable memory for integration into textile to serve as a basic building block for smart fabrics and wearable electronics.

“This technology reduces lead time and cost remarkably compared with existing manufacturing methods of cross-bar-shaped nanowire memory and simplifies its method of construction,” said Prof. Lee. “In particular, this technology will be used as a source technology to realize smart fabric, wearable computers, and textile electronic devices.”

The demand for sensor hubs, dedicated processing elements used for low-power sensor processing tasks, is booming. In fact due to “always on” sensor processing trends and the limitations of battery technology, the overall market for all types of sensor hubs will exceed 1.0 billion units in 2015, rising to nearly 2.0 billion in 2018, according to IHS Inc. (NYSE: IHS), a global source of critical information and insight. Samsung, Apple and Motorola have already been using sensor hubs in their smartphones for a number of years, and Apple, Motorola and Microsoft explicitly advertise their use of sensor hubs or sensor cores in certain smartphones.

“The sensor hub market is incredibly dynamic, changing rapidly over the last two years, due in large part to Apple’s iPhones,” said Marwan Boustany, senior analyst for IHS Technology. “When Apple shifted from a discrete microcontroller to an integrated application-processor-based solution for the iPhone 6S line in 2015, it signaled to other manufacturers that this approach had reached maturity.”

Sensor_Hub_Forecast

According to the IHS MEMS & Sensors for Consumer and Mobile Intelligence Service, sensor hubs for high-end smartphones are changing rapidly from discrete microcontrollers (MCUs) used in the iPhone 6, Samsung Galaxy S6, and other high-end smartphones, to sensor hubs that are integrated into the application processor (AP), as in the iPhone 6S and Huawei Mate S.

“AP-sensor hubs will increasingly dominate the midrange to high-end smartphone segments in the next few years,” Boustany said. “Samsung is also testing alternative approaches to sensor hubs using a Global-Navigation-Satellite-System-integrated sensor hub from Broadcom in its Note 4 and S6 smartphones. We also expect to see sensor hubs that are integrated in the sensor package to make inroads in smartphones, especially in the midrange and low-end segments.”

As the use of AP sensor hubs rises, market share for MCU and other discrete sensor hubs will decline; however, because wearable devices require long battery life in a small package, they will continue to rely on discrete MCUs and field-programmable gate arrays (FPGAs). With increasing numbers of smart watches entering the market, Qualcomm’s Snapdragon 400 and other AP sensor hubs have also begun to penetrate the wearable-device market.

“Apple has chosen to use a discrete MCU in the first-generation Apple Watch, but the company may follow its handset strategy and integrate the sensor hub into its custom application processor in later generations,” Boustany said. “Smartwatches will likely follow trends seen in the smartphone segment, but with a higher penetration of MCUs than smartphones, due to tighter power-saving requirements.”