Category Archives: Microscopy

Portland, OR — November 4, 2015 — JEOL‘s new JSM-IT100 is the latest addition to its InTouchScope Series of Scanning Electron Microscopes. Representing 50 years of industry leadership with advances in SEM, the IT100 is a simple-to-use versatile, research-grade SEM with a compact ergonomic design.

JEOL JSM-IT100_20Featuring expanded EDS analysis capabilities and ports for multiple detectors, the InTouchScope is a versatile workhorse SEM that can be configured to meet individual lab requirements at an exceptional value. It offers high resolution imaging and a range of acceleration voltages at both high and low vacuum modes.

The IT100 is a remarkably intuitive, high throughput microscope designed to streamline workflow in any lab. Touchscreen operation, or traditional keyboard and mouse interface are at the operator’s fingertips. Fast data acquisition make imaging and analysis of samples a simple task.

With the IT100, it is simple to quickly obtain high quality images using both Secondary Electron and Backscatter Imaging. The embedded JEOL EDS system with silicon drift detector technology now includes Spectral Mapping, Multi-Point Analysis, Automatic Drift Compensation, Partial area, Line Scan, and Mapping Filter functions.

JEOL’s popular InTouchScope series includes the NeoScope benchtop SEM with selectable HV/LV and the JSM-IT300LV with advanced analytical capabilities and imaging of large, intact samples.

Hillsboro, Ore. — November 2, 2015 — FEI today announced the new Helios™ G4 DualBeam series, which offers the highest throughput ultra-thin TEM lamella preparation for leading-edge semiconductor manufacturing and failure analysis applications. The new DualBeam series, which includes FX and HX models, takes a significant leap forward in both technological capability and ease-of-use.

The new Phoenix focused ion beam (FIB) makes finer cuts with higher precision and simplifies the creation of ultra-thin (sub 10nm) lamella for transmission electron microscopy (TEM) imaging. The FX is a flexible system that delivers dramatically improved STEM resolution – down to sub-three Ångströms – and significantly shortens the time to data for failure analysis. Images can now be obtained within minutes of completing the lamella, rather than the hours or days required previously to finalize the images on a stand-alone S/TEM system. The HX model is geared specifically for high-throughput TEM lamella production. It features an automated QuickFlip holder that reduces sample preparation times.

“FEI is the first to market with a TEM sample preparation solution capable of making 7nm thick lamella, addressing the needs of our customers who are developing next-generation devices,” states Rob Krueger, vice president and general manager of FEI’s semiconductor business. “In addition, by offering the ability to achieve sub-three Ångström image resolution in a DualBeam, failure analysis labs can now dramatically cut ‘time to data’ without compromising image quality. And, by combining high-resolution imaging and sample preparation on one system, we have reduced the amount of valuable lab real estate required.”

Graphene has generally been described as a two-dimensional structure — a single sheet of carbon atoms arranged in a regular structure — but the reality is not so simple. In reality, graphene can form wrinkles which make the structure more complicated, potentially being applied to device systems. The graphene can also interact with the substrate upon which it is laid, adding further complexity. In research published in Nature Communications, RIKEN scientists have now discovered that wrinkles in graphene can restrict the motion of electrons to one dimension, forming a junction-like structure that changes from zero-gap conductor to semiconductor back to zero-gap conductor. Moreover, they have used the tip of a scanning tunneling microscope to manipulate the formation of wrinkles, opening the way to the construction of graphene semiconductors not through chemical means — by adding other elements — but by manipulating the carbon structure itself in a form of “graphene engineering.”

The tip of the scanning tunneling microscope (in yellow-orange) is moved over the graphene and the nanowrinkle.

The tip of the scanning tunneling microscope (in yellow-orange) is moved over the graphene and the nanowrinkle.

The discovery began when the group was experimenting with creating graphene films using chemical vapor deposition, which is considered the most reliable method. They were working to form graphene on a nickel substrate, but the success of this method depends heavily on the temperature and cooling speed.

According to Hyunseob Lim, the first author of the paper, “We were attempting to grow graphene on a single crystalline nickel substrate, but in many cases we ended up creating a compound of nickel and carbon, Ni2C, rather than graphene. In order to resolve the problem, we tried quickly cooling the sample after the dosing with acetylene, and during that process we accidentally found small nanowrinkles, just five nanometers wide, in the sample.”

They were able to image these tiny wrinkles using scanning tunneling microscopy, and discovered that there were band gap openings within them, indicating that the wrinkles could act as semiconductors. Normally electrons and electron holes flow freely through a conductor without a band gap, but when it is a semiconductor there are band gaps between the permitted electron states, and the electrons can only pass through these gaps under certain conditions. This indicates that the graphene could, depending on the wrinkles, become a semiconductor. Initially they considered two possibilities for the emergence of this band gap. One is that the mechanical strain could cause a magnetic phenomenon, but they ruled this out, and concluded that the phenomenon was caused by the confinement of electrons in a single dimension due to “quantum confinement.”

According to Yousoo Kim, head of the Surface and Interface Science Laboratory, who led the team, “Up until now, efforts to manipulate the electronic properties of graphene have principally been done through chemical means, but the downside of this is that it can lead to degraded electronic properties due to chemical defects. Here we have shown that the electronic properties can be manipulated merely by changing the shape of the carbon structure. It will be exciting to see if this could lead to ways to find new uses for graphene.”


Hyunseob Lim, Jaehoon Jung, Rodney S. Ruoff & Yousoo Kim, “Structurally driven one-dimensional electron confinement in sub-5-nm graphene nanowrinkles”, Nature Communications (2015), 10.1038/ncomms9601

A report that resulted from a workshop funded by Semiconductor Research Corporation (SRC) and National Science Foundation (NSF) outlines key factors limiting progress in computing—particularly related to energy consumption—and novel device and architecture research that can overcome these barriers. A summary of the report’s findings can be found at the end of this article; the full report can be accessed here.

The findings and recommendations in the report are in alignment with the nanotechnology-inspired Grand Challenge for Future Computing announced on October 20 by the White House Office of Science and Technology Policy. The Grand Challenge calls for new approaches to computing that will operate with the efficiency of the human brain. It also aligns with the National Strategic Computing Initiative (NSCI) announced by an Executive Order signed by the President on July 29.

Energy efficiency is vital to improving performance at all levels. This includes from devices and transistors to large IT systems, as well from small sensors at the edge of the Internet of Things (IoT) to large data centers in cloud and supercomputing systems.

“Fundamental research on hardware performance, complex system architectures, and new memory/storage technologies can help to discover new ways to achieve energy-efficient computing,” said Jim Kurose, the Assistant Director of the National Science Foundation (NSF) for Computer and Information Science and Engineering (CISE). “Partnerships with industry, including SRC and its member companies, are an important way to speed the adoption of these research findings.”

Performance improvements today are limited by energy inefficiencies that result in overheating and thermal management issues. The electronic circuits in computer chips still operate far from any fundamental limits to energy efficiency, and much of the energy used by today’s computers is expended moving data between memory and the central processor.

At the same time as increases in performance slow, the amount of data being produced is exploding. By 2020, an estimated 44 zettabytes of data (1 zettabyte equals 1 trillion gigabytes) will be created on an annual basis.

“New devices, and new architectures based on those devices, could take computing far beyond the limits of today’s technology. The benefits to society would be enormous,” said Tom Theis, Nanoelectronics Research Initiative (NRI) Executive Director at SRC, the world’s leading university-research consortium for semiconductor technologies.

Inspired by the neural architecture of a macaque brain, this neon swirl is the wiring diagram for a new kind of computer that, by some definitions, may soon be able to think. (Credit: Emmett McQuinn, IBM Research - Almaden)

Inspired by the neural architecture of a macaque brain, this neon swirl is the wiring diagram for a new kind of computer that, by some definitions, may soon be able to think. (Credit: Emmett McQuinn, IBM Research – Almaden)

In order to realize these benefits, a new paradigm for computing is necessary. A workshop held April 14-15, 2015 in Arlington, Va., and funded by SRC and NSF convened experts from industry, academia and government to identify key factors limiting progress and promising new concepts that should be explored. The report being announced today resulted from the workshop discussions and provides a guide to future basic research investments in energy-efficient computing.

The report builds upon an earlier report funded by the Semiconductor Industry Association, SRC and NSF on Rebooting the IT Revolution.

To achieve the Nanotechnology Grand Challenge and the goals of the NSCI, multi-disciplinary fundamental research on materials, devices and architecture is needed. NSF and SRC, both individually and together, have a long history of supporting long-term research in these areas to address such fundamental, high-impact science and engineering challenges.

Report Findings

Broad Conclusions

Research teams should address interdisciplinary research issues essential to the demonstration of new device concepts and associated architectures. Any new device is likely to have characteristics very different from established devices. The interplay between device characteristics and optimum circuit architectures therefore means that circuit and higher level architectures must be co-optimized with any new device. Devices combining digital and analog functions or the functions of logic and memory may lend themselves particularly well to unconventional information processing architectures. For maximum impact, research should focus on devices and architectures which can enable a broad range of useful functions, rather than being dedicated to one function or a few particular functions.

Prospects for New Devices

Many promising research paths remain relatively unexplored. For example, the gating of phase transitions is a potential route to “steep slope” devices that operate at very low voltage. Relevant phase transitions might include metal-insulator transitions, formation of excitonic or other electronic condensates, and various transitions involving structural degrees of freedom. Other promising mechanisms for low-power switching may involve transduction. Magnetoelectric devices, in which an external voltage state is transduced to an internal magnetic state, exemplify the concept. However, transduction need not be limited to magnetoelectric systems.

In addition to energy efficiency, switching speed is an important criterion in choice of materials and device concepts. For example, most nanomagnetic devices switch by magnetic precession, a process which is rather slow in the ferromagnetic systems explored to date. Magnetic precession switching in antiferromagnetic or ferrimagnetic materials could be one or more orders of magnitude faster. Other novel physical systems could be still faster. For example, electronic collective states could, in principle, be switched on sub-picosecond time scales.

More generally, devices based on computational state variables beyond magnetism and charge (or voltage) could open many new possibilities.

Another relatively unexplored path to improved energy efficiency is the implementation of adiabatically switched devices in energy-conserving circuits. In such circuits, the phase of an oscillation or propagating wave may represent digital state; devices and interconnections must together constitute circuits that are non-dissipative. Nanophotonic, plasmonic, spin wave or other lightly damped oscillatory systems might be well-suited for such an approach. Researchers should strive to address the necessary components of a practical engineering solution, including mechanisms for correction of unavoidable phase and amplitude errors.

Networks of coupled non-linear oscillators have been explored for non-Boolean computation in applications such as pattern recognition. Potential technological approaches include nanoelectromechanical, nanophotonic, and nanomagnetic oscillators. Researchers should strive for generality of function and should address the necessary components of a practical engineering solution, including devices, circuits, and architectures that allow reliable operation in the presence of device variability and environmental fluctuations.

Prospects for New Architectures

While appropriate circuits and higher level architectures should be explored and co-developed along with any new device concept, certain novel device concepts may demand greater emphasis on higher-level architecture. For example, hysteretic devices, combining the functions of non-volatile logic and memory, might enhance the performance of established architectures (power gating in microprocessors, reconfiguration of logic in field programmable gate arrays), but perhaps more important, they might play an enabling role in novel architectures (compute in memory, weighting of connections in neuromorphic systems, and more). As a second example, there has been great progress in recent years in the miniaturization and energy efficiency of linear and non-linear photonic devices and compact light emitters. It is possible that these advances will have their greatest impact, not in the ongoing replacement of metal wires by optical connections, but rather in enabling new architectures for computing. Computation “in the network” is one possible direction. In general, device characteristics and architecture appear to be highly entwined in oscillatory or energy-conserving systems. Key device characteristics may be inseparable from the coupling (connections) between devices. For non-Boolean computation, optimum architectures and the range of useful algorithms will depend on these characteristics.

In addition to the examples above, many other areas of architectural research might leverage emerging device concepts to obtain order of magnitude improvements in the energy efficiency of computing. Research topics might include architectures for heterogeneous systems, architectures that minimize data movement, neuromorphic architectures, and new approaches to Stochastic Computing, Approximate Computing, Cognitive Computing and more.

Slideshow: 2015 IEDM Preview

October 20, 2015
The 2015 IEDM Conference will be held in Washington DC.

The 2015 IEDM will be held in Washington DC.

This year marks the 61st annual IEEE International Electron Devices Meeting (IEDM). It is arguably the world’s pre-eminent forum for reporting technological breakthroughs in semiconductor and electronic device technology, design, manufacturing, physics, and modeling. The conference focuses not only on devices in silicon, compound and organic semiconductors, but also in emerging material systems.

As usual, Solid State Technology will be reporting insights from bloggers and industry partners during the conference. This slideshow provides an advance look at some of the most newsworthy topics and papers that will be presented at this year’s meeting, which will be held at the Washington, D.C. Hilton from December 7-9, 2015.

Click here to start the slideshow

Check back here for more articles and information about IEDM 2015:

Helpful conference links:

By Tom Abate, Stanford Engineering

Stanford chemical engineering Professor Zhenan Bao and her team have created a skin-like material that can tell the difference between a soft touch and a firm handshake. The device on the "golden fingertip" is the skin-like sensor developed by Stanford engineers.

Stanford chemical engineering Professor Zhenan Bao and her team have created a skin-like material that can tell the difference between a soft touch and a firm handshake. The device on the “golden fingertip” is the skin-like sensor developed by Stanford engineers. (Photo: Bao Lab, Stanford)

Stanford engineers have created a plastic “skin” that can detect how hard it is being pressed and generate an electric signal to deliver this sensory input directly to a living brain cell.

Zhenan Bao, a professor of chemical engineering at Stanford, has spent a decade trying to develop a material that mimics skin’s ability to flex and heal, while also serving as the sensor net that sends touch, temperature and pain signals to the brain. Ultimately she wants to create a flexible electronic fabric embedded with sensors that could cover a prosthetic limb and replicate some of skin’s sensory functions.

Bao’s work, reported today in Science, takes another step toward her goal by replicating one aspect of touch, the sensory mechanism that enables us to distinguish the pressure difference between a limp handshake and a firm grip.

“This is the first time a flexible, skin-like material has been able to detect pressure and also transmit a signal to a component of the nervous system,” said Bao, who led the 17-person research team responsible for the achievement.

Benjamin Tee, a recent doctoral graduate in electrical engineering; Alex Chortos, a doctoral candidate in materials science and engineering; and Andre Berndt, a postdoctoral scholar in bioengineering, were the lead authors on the Science paper.

Digitizing Touch

Stanford sensor closeup

A closeup of the sensor. (Photo: Bao Lab, Stanford)

The heart of the technique is a two-ply plastic construct: the top layer creates a sensing mechanism and the bottom layer acts as the circuit to transport electrical signals and translate them into biochemical stimuli compatible with nerve cells. The top layer in the new work featured a sensor that can detect pressure over the same range as human skin, from a light finger tap to a firm handshake.

Five years ago, Bao’s team members first described how to use plastics and rubbers as pressure sensors by measuring the natural springiness of their molecular structures. They then increased this natural pressure sensitivity by indenting a waffle pattern into the thin plastic, which further compresses the plastic’s molecular springs.

To exploit this pressure-sensing capability electronically, the team scattered billions of carbon nanotubes through the waffled plastic. Putting pressure on the plastic squeezes the nanotubes closer together and enables them to conduct electricity.

This allowed the plastic sensor to mimic human skin, which transmits pressure information to the brain as short pulses of electricity, similar to Morse code. Increasing pressure on the waffled nanotubes squeezes them even closer together, allowing more electricity to flow through the sensor, and those varied impulses are sent as short pulses to the sensing mechanism. Remove pressure, and the flow of pulses relaxes, indicating light touch. Remove all pressure and the pulses cease entirely.

The team then hooked this pressure-sensing mechanism to the second ply of their artificial skin, a flexible electronic circuit that could carry pulses of electricity to nerve cells.

Importing the Signal

Bao’s team has been developing flexible electronics that can bend without breaking. For this project, team members worked with researchers from PARC, a Xerox company, which has a technology that uses an inkjet printer to deposit flexible circuits onto plastic. Covering a large surface is important to making artificial skin practical, and the PARC collaboration offered that prospect.

Finally the team had to prove that the electronic signal could be recognized by a biological neuron. It did this by adapting a technique developed by Karl Deisseroth, a fellow professor of bioengineering at Stanford who pioneered a field that combines genetics and optics, called optogenetics. Researchers bioengineer cells to make them sensitive to specific frequencies of light, then use light pulses to switch cells, or the processes being carried on inside them, on and off.

For this experiment the team members engineered a line of neurons to simulate a portion of the human nervous system. They translated the electronic pressure signals from the artificial skin into light pulses, which activated the neurons, proving that the artificial skin could generate a sensory output compatible with nerve cells.

Optogenetics was only used as an experimental proof of concept, Bao said, and other methods of stimulating nerves are likely to be used in real prosthetic devices. Bao’s team has already worked with Bianxiao Cui, an associate professor of chemistry at Stanford, to show that direct stimulation of neurons with electrical pulses is possible.

Bao’s team envisions developing different sensors to replicate, for instance, the ability to distinguish corduroy versus silk, or a cold glass of water from a hot cup of coffee. This will take time. There are six types of biological sensing mechanisms in the human hand, and the experiment described in Science reports success in just one of them.

But the current two-ply approach means the team can add sensations as it develops new mechanisms. And the inkjet printing fabrication process suggests how a network of sensors could be deposited over a flexible layer and folded over a prosthetic hand.

“We have a lot of work to take this from experimental to practical applications,” Bao said. “But after spending many years in this work, I now see a clear path where we can take our artificial skin.”

JEOL’s benchtop SEM makes it possible to bring basic high resolution imaging and analysis features of a full-sized Scanning Electron Microscope into the lab. It fits into both small spaces and economical budgets, and its simple operation and versatile functions complement the workflow with optical microscopes or larger SEMs.

With recent upgrades, JEOL has introduced a new model, the JSM-6000Plus, the third generation of the popular NeoScope benchtop SEM designed for convenience and ease of use. The NeoScope delivers fast, high magnification electron microscopy with more functionality than typical benchtop SEMs.

JEOL understands that even the smallest microscope needs the flexibility of selectable high and low kV, selectable beam currents, and up to 60,000X magnification to be a valuable resource.

New features enhance this flexibility. The JSM-6000Plus now offers high sensitivity backscatter electron detection with a BSE detector manufactured by JEOL to detect contrast between areas of the sample with different chemical compositions.

The simplicity of design with touchscreen operation make the NeoScope an ergonomic, easy-to-operate SEM for rapid inspection of electronics, pharmaceuticals, forensic evidence, and a wide variety of materials and organic samples.

The JEOL NeoScope is the culmination of more than 50 years of expertise in SEM development and is supported by the award-winning service organization at JEOL USA.

The NeoScope is available exclusively from Nikon Metrology, Inc., a leading supplier of optical microscopes, through a business alliance between JEOL and Nikon.

Winners of prestigious annual awards have been announced by the Awards Committee of SPIE, the international society for optics and photonics. The awards recognize outstanding technical accomplishments and meritorious service to the society.

Recipients are:

Gold Medal of the Society: Nader Engheta, University of Pennsylvania, for contributions to optical engineering of metamaterials and nanoscale plasmonics, metamaterial-based optical nanocircuits, and biologically-inspired optical imaging. The Gold Medal is the highest honor bestowed by SPIE.

Britton Chance Biomedical Optics Award: Lihong Wang, Washington University in St. Louis, for pioneering contributions and visionary leadership in photoacoustic tomography, photoacoustic microscopy, and photon transport modeling.

A.E. Conrady Award: Richard Juergens, Raytheon Missile Systems, for leadership in optical system design, optical component fabrication and testing, development of optimization techniques and tolerancing methods, and training and mentoring of optical engineers.

Dennis Gabor Award: Kazuyoshi Itoh, Osaka University, for contributions to incoherent holography and nonlinear optical microscopy through pioneering work on coherence-based multispectral and 3D imaging, and nonlinear optical imaging and manipulations of biological and inorganic industrial materials.

George W. Goddard Award: Grady Tuell, Georgia Tech Research Institute, for foundational work in bathymetric lidar and data fusion, and advances in airborne lidar remote sensing including real-time calculation of total propagated positioning error.

G.G. Stokes Award: Aristide Dogariu, CREOL, University of Central Florida, for new theoretical concepts and innovative methods for understanding and measuring polarization properties of light-matter interaction.

Chandra S. Vikram Award in Optical Metrology: Guillermo Kaufmann, Instituto de Física Rosario (CONICET-UNR) for work in speckle metrology and its applications in material science, experimental mechanics and nondestructive testing, and development of novel fringe analysis methods.

Frits Zernike Award in Microlithography: Ralph Dammel, AZ Electronics Materials, for contributions in photoresist, anti-reflective coating, and directed self-assembly materials for semiconductor microlithography.

SPIE Early Career Achievement Award – Academic: Miriam Serena Vitiello, for research on semiconductor laser sources and electronic high frequency nanodetectors opening new frontiers in terahertz photonics and optoelectronics.

SPIE Early Career Achievement Award – Industry: Alan Lee, LongWave Photonics LLC, for pioneering work on stand-off distance real-time THz imaging enabling basic working principles for commercial THz imagers/cameras.

SPIE Educator Award: Virendra Mahajan, for sharing knowledge in the area of optical imaging, aberrations, and wavefront analysis, as a volunteer teacher and author.

SPIE Technology Achievement Award: Keith Doyle, MIT Lincoln Laboratory, for contributions to integrated analysis of optical systems incorporating optical, thermal, and structural engineering.

Members of the photonics community may nominate colleagues for SPIE awards through 1 October each year. Information at

SPIE is the international society for optics and photonics, a not-for-profit organization founded in 1955 to advance light-based technologies. The Society serves nearly 256,000 constituents from approximately 155 countries, offering conferences, continuing education, books, journals, and a digital library in support of interdisciplinary information exchange, and professional networking. SPIE provided more than $3.4 million in support of education and outreach programs in 2014.

The eBeam Initiative, a forum dedicated to the education and promotion of new semiconductor manufacturing approaches based on electron beam (eBeam) technologies, today announced that its top theme for 2015 will be the reactivation of the density benefits of Moore’s Law through eBeam technology. Efforts to educate, collaborate and promote this theme to the photomask and lithography community will include focusing on how new developments in multi-beammask writing and model-based mask data preparation (MB-MDP), coupled with complex inverse lithography technology (ILT), can reverse the trend of rectilinear constraints on mask designs and enable continued density scaling at the 10-nm node and beyond using 193-nm immersion lithography techniques.

In related news, Holon, a leading photomask and wafer metrology provider, and Photronics, a leading semiconductor photomask manufacturer, have joined the eBeam Initiative. “We are very pleased to welcome Holon and Photronics as new members to our eBeam community, and look forward to adding their unique perspectives, collaboration and industry leadership in support of the Initiative’s educational goals,” stated Aki Fujimura, CEO of D2S, the managing company sponsor of the eBeam Initiative. Industry luminary Dr. Chris Progler, chief technology officer and strategic planning at Photronics, will provide his perspective on the 10-nm logic node at the eBeam Initiative’s annual luncheon event taking place next week at the SPIE Advanced Lithography Conference in San Jose, Calif.

Among other developments, the eBeam Initiative will continue to publish its Fine Line Video Journal, which offers unique insights into emerging industry developments that are shaping the wider eBeam technology ecosystem for advanced photomask and semiconductor manufacturing. A video interview with Colin Harris, founder and chief operating officer of PMC-Sierra, on the rising density benefit gap in Moore’s Law from a fabless semiconductor perspective, has been pre-released and is available for download at Aki Fujimura will highlight this theme in his opening address at the eBeam Initiative luncheon event at the SPIE Advanced Lithography Conference.

“As Colin Harris has stated, while the performance per watt aspect of Moore’s Law has held true, we have reached a point with traditional rules-based designs where the rules are so conservative and the implementation costs are so high that the semiconductor industry has started to lose the economic benefits of scaling to smaller design nodes for system-on-chip (SOC) designs,” stated Fujimura. “A simulation-based approach combining complex ILT, MB-MDP and existing variable shaped beam (VSB) mask writers in parallel with the impending emergence of multi-beam mask writing are providing platforms to enable the semiconductor industry to reverse this trend and reactivate the density benefits associated with Moore’s Law. This is truly an exciting time to be a part of the eBeam ecosystem to help take part in our community’s contributions to Moore’s Law.”

Colin Harris’ video along with additional video interviews will be included in the Spring 2015 edition of the Fine Line Video Journal, which will be posted on the eBeam Initiative website on March 16.

The eBeam Initiative provides a forum for educational and promotional activities regarding new semiconductor manufacturing approaches based on electron beam (eBeam) technologies.

Rudolph Technologies has introduced its new SONUS Technology for measuring thick films and film stacks used in copper pillar bumps and for detecting defects, such as voids, in through silicon vias (TSVs). Copper pillar bumps are a critical component of many advanced packaging technologies and TSVs provide a means for signals to pass through multiple vertically stacked chips in three dimensional integrated circuits (3DIC). The new SONUS Technology is non-contact and non-destructive, and is designed to provide faster, less costly measurements and greater sensitivity to smaller defects than existing alternatives such as X-ray tomography and acoustic microscopy.

“SONUS Technology meets a critical need for measuring and inspecting the structures used to connect chips to each other and to the outside world,” said Tim Kryman, Rudolph’s director of metrology product management. “Copper pillar bumps and TSVs are critical interconnect technologies enabling 2.5D and 3D packaging. The mechanical integrity of the interconnect and final device performance are directly dependent on tight control of the plating processes used to create copper pillar bumps. Likewise, the quality of the TSV fill is critical to the electrical performance of stacked devices. This new technology allows us to measure individual films and film stacks with thicknesses up to 100µm, and detect voids as small as 0.5µm in TSVs with aspect ratios of 10:1 or greater.”

Kryman added, “SONUS Technology builds on the expertise we developed in acoustic metrology for our industry-standard MetaPULSE systems, which are widely used for front-end metal film metrology. By offering similar improvements in yield and time-to-profitability in high volume manufacturing (HVM), SONUS offers a compelling value proposition to advanced packaging customers.”

Both MetaPULSE and SONUS systems use a laser to initiate an acoustic disturbance at the surface of the sample. As the acoustic wave travels down through the film stack, it is partially reflected at interfaces between different materials. Although the detection schemes are different, the reflected waves are detected when they return to the surface and the elapsed time is used to calculate the thickness of each layer. In the case of SONUS Technology, two lasers are used. The first laser excites the sample and the second probes for the returning acoustics. This decouples excitation and detection allowing SONUS to continuously probe the sample resulting in a much larger film thickness range. So, where MetaPULSE can measure metal films and stacks to ~10 microns, SONUS can measure films in excess of 100 microns. In addition, SONUS Technology’s use of interferometry to characterize the surface displacement provides a rich data set that can be analyzed to not only characterize film thickness, but perform defect detection.

The primary alternatives for such measurements are X-ray based tomographic analysis and acoustic microscopy. SONUS Technology’s ability to detect voids as small as half a micrometer is approximately twice as good as current X-ray techniques, which have a spatial resolution of about 1 micrometer. Acoustic microscopy can make similar measurements, but the sample must be immersed in water, which, though not strictly destructive, does effectively preclude the return of the sample to production. SONUS is both non-contact and non-destructive and is designed for R&D and high-volume manufacturing.

In the run up to the product introduction, Rudolph worked closely with TEL NEXX to develop SONUS-based process control for pillar bump and TSV plating processes. Arthur Keigler, chief technology officer of TEL NEXX, said, “We are attracted by the opportunity SONUS Technology offers our mutual customers in the advanced packaging market. The ability to measure multi-metal film stacks for Cu pillar, and then continue to use the same tool for TSV void detection offers immediate productivity and cost benefits to manufacturing and development groups alike.”

While Rudolph is initially focused on using the technology for copper pillar bump process metrology and TSV inspection, they are also investigating other applications, ranging from detecting film delamination to metrology and process control for MEMS fabrication processes.