Category Archives: Packaging Materials

Germanene is a 2D material that derives from germanium and is related to graphene. As it is not stable outside the vacuum chambers in which is it produced, no real measurements of its electronic properties have been made. Scientists led by Prof. Justin Ye of the University of Groningen have now managed to produce devices with stable germanene. The material is an insulator, and it becomes a semiconductor after moderate heating and a very good metallic conductor after stronger heating. The results were published in the journal Nano Letters.

Germanane is converted into germanene by thermal annealing, which removes the hydrogen (red). Credit: Ye Lab / University of Groningen

Materials of just one atomic layer are of interest in the construction of new types of microelectronics. The best known of these, graphene, is an excellent conductor. Materials like silicon and germanium could be interesting as well, as they are fully compatible with well-established protocols for device fabrication, and could be seamlessly integrated into the present semiconductor technology.

Unstable

‘But the 2D version of germanium, germanene, is very unstable’, explains University of Groningen Associate Professor of Device Physics Justin Ye. Germanene is made from germanium by adding calcium. The calcium ions create 2D layers from a 3D crystal and are then replaced by hydrogen. These 2D layers of germanium and hydrogen are called germanane. But once the hydrogen is removed to form germanene, the material becomes unstable.

Ye and his colleagues solved this in a remarkably simple way. They made devices with the stable germanane, and then heated the material to remove the hydrogen. This resulted in stable devices with germanene, which allowed the scientists to study its electronic properties.

Hydrogen

‘The initial material was an insulator’, says Ye. A Ph.D. student from his group heated these devices, which is a tried and tested method to increase conductivity. He noted that the material became very conductive, and its resistance was just one order of magnitude above that of graphene. ‘So it became an excellent metallic conductor.’ Further experiments showed that moderate heating (up to 200°C) produced semiconducting germanane.

Germanene can, therefore, be an insulator, a semiconductor or a metallic conductor, depending on the heat treatment with which it is processed. It remains stable after being cooled to room temperature. The heating causes multilayer flakes of germanene to become thinner – confirmation that the change in conductivity is most likely caused by the disappearance of hydrogen.

Spintronic device

Germanene could be of interest in the construction of spintronic devices. These devices use a current of electron spins. This is a quantum mechanical property of electrons, which can best be imagined as electrons spinning around their own axis, causing them to behave like small compass needles. Graphene is an excellent conductor of electron spins, but it is hard to control spins in this material because of their weak interaction with the carbon atoms (spin-orbit coupling).

‘The germanium atoms are heavier, which means there is a stronger spin-orbit coupling’, says Ye. This would provide better control of spins. Being able to construct metallic germanene with both excellent conductivity and strong spin-orbit coupling should therefore pave the way to spintronic devices.

Researchers from the University of Houston have reported significant advances in stretchable electronics, moving the field closer to commercialization.

Researchers from the University of Houston have reported significant advances in the field of stretchable, rubbery electronics. Credit: University of Houston

In a paper published Friday, Feb. 1, in Science Advances, they outlined advances in creating stretchable rubbery semiconductors, including rubbery integrated electronics, logic circuits and arrayed sensory skins fully based on rubber materials.

Cunjiang Yu, Bill D. Cook Assistant Professor of mechanical engineering at the University of Houston and corresponding author on the paper, said the work could lead to important advances in smart devices such as robotic skins, implantable bioelectronics and human-machine interfaces.

Yu previously reported a breakthrough in semiconductors with instilled mechanical stretchability, much like a rubber band, in 2017.

This work, he said, takes the concept further with improved carrier mobility and integrated electronics.

“We report fully rubbery integrated electronics from a rubbery semiconductor with a high effective mobility … obtained by introducing metallic carbon nanotubes into a rubbery semiconductor with organic semiconductor nanofibrils percolated,” the researchers wrote. “This enhancement in carrier mobility is enabled by providing fast paths and, therefore, a shortened carrier transport distance.”

Carrier mobility, or the speed at which electrons can move through a material, is critical for an electronic device to work successfully, because it governs the ability of the semiconductor transistors to amplify the current.

Previous stretchable semiconductors have been hampered by low carrier mobility, along with complex fabrication requirements. For this work, the researchers discovered that adding minute amounts of metallic carbon nanotubes to the rubbery semiconductor of P3HT – polydimethylsiloxane composite – leads to improved carrier mobility by providing what Yu described as “a highway” to speed up the carrier transport across the semiconductor.

The intelliFLEX Innovation Alliance announced today that Mark Majewski, a 30-year veteran of the Canadian technology industry and former geographic director at a major semiconductor company, has succeeded Peter Kallai as CEO.

Mr. Majewski has extensive experience in the electronics and technology industries in Canada, having overseen the generation of hundreds of millions of dollars at STMicroelectronics while running its East Central U.S. and Canada regions. He’s also been a key leader at several startups, volunteers as a mentor at the RIC Centre and Haltech, and most recently was the technology lead for business development at Ontario Centres of Excellence (OCE).

Mr. Majewski’s goal as CEO is to unite the growing critical mass of Canadian printable, flexible and hybrid electronics (FHE) companies and research with the country’s electronics and semiconductor industries. With his decades of technology experience, Mr. Majewski has the breadth of contacts, experience, and knowledge to successfully position intelliFLEX and its members alongside this massive industry.

“I’m honoured to have been named the next intelliFLEX CEO. I’ve taken this role because I believe in FHE and its future,” says Mr. Majewski. “All electronics players in Canada who want to expand their capabilities should be looking at this technology as it goes mainstream. Not only does FHE open the doors to new products and applications, it also has incredible value in augmenting and improving everyday electronics products that already exist.”

Indeed, as microelectronics and semiconductor companies hit the limits of Moore’s Law for integrated circuits, mainstream companies are searching for new ways to produce electronic components more efficiently for new and existing applications.

That’s where printable, flexible and hybrid electronics come in: FHE, which represents a $31.6B global market opportunity, uses next-generation additive and manufacturing electronics technologies that can help all electronics players in Canada. This strategy has already been embraced in the U.S. where a cross-pollination of mainstream electronics, FHE, and semiconductors is occurring.

“I’ve cherished the opportunity to work with intelliFLEX,” said outgoing CEO Peter Kallai, who founded intelliFLEX and will remain involved by supporting Mr. Majewski during the transition period and sitting on the board of directors. “However, what we need to do is move the organization into the mainstream electronics industry and be the rising tide of the ecosystem that lets all our members sail further, faster and easier.

“We needed a professional from that industry, with the right background, to do that. And I strongly believe Mark will take intelliFLEX to the next level.”

At the same time, intelliFLEX will also move its head office from Ottawa to the Greater Toronto Area. This will help the organization be physically closer to the heart of Canada’s electronics industry, of which the majority is located in Toronto. Seventy-five per cent of intelliFLEX members are in either Ontario or Quebec.

A team of researchers from Lehigh University, Oak Ridge National Laboratory, Lebanon Valley College and Corning Inc. has demonstrated, for the first time, that crystals manufactured by lasers within a glass matrix maintain full ferroelectric functionality.

Ferroelectric single-crystal-architecture-in-glass is a new class of metamaterials that would enable active integrated optics if the ferroelectric behavior is preserved within the confines of glass. We demonstrate using lithium niobate crystals fabricated in lithium niobosilicate glass by femtosecond laser irradiation that not only such behavior is preserved, the ferroelectric domains can be engineered with a DC bias. A piezoresponse force microscope is used to characterize the piezoelectric and ferroelectric behavior. The piezoresponse correlates with the orientation of the crystal lattice as expected for unconfined crystal, and a complex micro- and nano-scale ferroelectric domain structure of the as-grown crystals is revealed. Credit: Keith Veenhuizen, Sean McAnany, Rama Vasudevan, Daniel Nolan, Bruce Aitken, Stephen Jesse, Sergei V. Kalinin, Himanshu Jain and Volkmar Dierolf

“This includes the ability to uniformly orient and reverse orient the ferroelectric domains with an electric field?despite the fact that the crystal is strongly confined by the surrounding glass,” says Volkmar Dierolf, Chair of Lehigh University’s Department of Physics and one of the scientists who worked on the experiments that resulted in these findings.

Dierolf, who holds a joint appointment with Lehigh’s Department of Materials Science and Engineering part of the P.C. Rossin College of Engineering and Applied Science, is co-Principal Investigator on a National Science Foundation (NSF)-funded project, Crystal in Glass, along with Principal Investigator Himanshu Jain, Diamond Distinguished Chair of Lehigh’s Department of Materials Science and Engineering. The group has become a world leader in producing single crystals in glass by localized laser irradiation. Read more about their work: “Crossing a critical threshold” and “Lehigh scientists fabricate a new class of crystalline solid.”

The team conducted the first detailed examination of the piezoelectric and ferroelectric properties of laser induced crystals confined in glass. They found that the as-grown crystals possess a complex ferroelectric domain structure that can be manipulated via the application of a DC bias. The findings have been published online today in MRS Communications in a paper called “Ferroelectric domain engineering of lithium niobate single crystal confined in glass.”

“The findings open up the possibility of a new collection of optical devices that use fully functional laser-fabricated crystals in glass which rely on the precise control of the ferroelectric domain structure of the crystal,” said Keith Veenhuizen, currently Assistant Professor, Department of Physics at Lebanon Valley College and the lead author of the paper, which builds on the work he did as a graduate student at Lehigh.

Applications for such technology include use in modern fiber optic technology used for data transmission.

“Being able to embed such functional single crystal architectures within a glass enables high efficiency coupling to existing glass fiber networks,” says Dierolf. “Such low loss links?that maximize performance?are of particular importance for future quantum information transfer system that are projected to take over the current schemes for optical communication,” adds Dierolf.

Water molecules distort the electrical resistance of graphene, but a team of European researchers has discovered that when this two-dimensional material is integrated with the metal of a circuit, contact resistance is not impaired by humidity. This finding will help to develop new sensors -the interface between circuits and the real world- with a significant cost reduction.

The many applications of graphene, an atomically-thin sheet of carbon atoms with extraordinary conductivity and mechanical properties, include the manufacture of sensors. These transform environmental parameters into electrical signals that can be processed and measured with a computer.

Due to their two-dimensional structure, graphene-based sensors are extremely sensitive and promise good performance at low manufacturing cost in the next years.

To achieve this, graphene needs to make efficient electrical contacts when integrated with a conventional electronic circuit. Such proper contacts are crucial in any sensor and significantly affect its performance.

But a problem arises: graphene is sensitive to humidity, to the water molecules in the surrounding air that are adsorbed onto its surface. H2O molecules change the electrical resistance of this carbon material, which introduces a false signal into the sensor.

However, Swedish scientists have found that when graphene binds to the metal of electronic circuits, the contact resistance (the part of a material’s total resistance due to imperfect contact at the interface) is not affected by moisture.

“This will make life easier for sensor designers, since they won’t have to worry about humidity influencing the contacts, just the influence on the graphene itself,” explains Arne Quellmalz, a PhD student at KTH Royal Institute of Technology (Sweden) and the main researcher of the research.

The study, published in the journal ACS Applied Materials & Interfaces, has been carried out experimentally using graphene together with gold metallization and silica substrates in transmission line model test structures, as well as computer simulations.

“By combining graphene with conventional electronics, you can take advantage of both the unique properties of graphene and the low cost of conventional integrated circuits.” says Quellmalz, “One way of combining these two technologies is to place the graphene on top of finished electronics, rather than depositing the metal on top the graphene sheet.”

As part of the European CO2-DETECT project, the authors are applying this new approach to create the first prototypes of graphene-based sensors. More specifically, the purpose is to measure carbon dioxide (CO2), the main greenhouse gas, by means of optical detection of mid-infrared light and at lower costs than with other technologies.

In addition to the KTH Royal Institute of Technology, the companies SenseAir AB from Sweden and Amo GmbH from Germany are likewise participants in the CO2-DETECT project, as is the Catalan Institute of Nanotechnology (ICN) from Barcelona.

Organic semiconductors enable the fabrication of large-scale printed and mechanically flexible electronic applications, and have already successfully established themselves on the market for displays in the form of organic light-emitting diodes (OLEDs). In order to break into further market segments, however, improvements in performance are still needed. Doping is the answer. In semiconductor technology, doping refers to the targeted introduction of impurities (also called dopants) into the semiconductor material of an integrated circuit. These dopants function as intentional “disturbances” in the semiconductor that can be used to specifically control the behaviour of the charge carriers and thus the electrical conductivity of the original material. Even the smallest amounts of these can have a very strong influence on electrical conductivity. Molecular doping is an integral part of the majority of commercial organic electronics applications. Until now, however, an insufficient fundamental physical understanding of the transport mechanisms of charges in doped organic semiconductors has prevented a further increase in conductivity to match the best inorganic semiconductors such as silicon.

Researchers from the Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and the Center for Advancing Electronics Dresden (cfaed) at TU Dresden, in cooperation with Stanford University and the Institute for Molecular Science in Okazaki, have now identified key parameters that influence electrical conductivity in doped organic conductors. The combination of experimental investigations and simulations has revealed that introducing dopant molecules into organic semiconductors creates complexes of two oppositely charged molecules. The properties of these complexes like the Coulomb attraction and the density of the complexes significantly determine the energy barriers for the transport of charge carriers and thus the level of electrical conductivity. The identification of important molecular parameters constitutes an important foundation for the development of new materials with even higher conductivity.

The results of this study have just been published in the renowned journal Nature Materials. While the experimental work and a part of the simulations were conducted at the IAPP, the Computational Nanoelectronics Group at the cfaed under the leadership of Dr. Frank Ortmann verified the theoretical explanations for the observations by means of simulations at the molecular level. In doing so, a comprehensive foundation for new applications for organic semiconductor technology has been created.

Laser systems specialist LPKF Laser & Electronics, based in Hannover, Germany has added a foundry service for thin glass substrates to its product portfolio. The company recently introduced the Laser-Induced Deep Etching technology, or LIDE for short, a process for the precise and highly efficient manufacturing of through-glass vias (TGV) and other deep micro features in thin glass substrates. The LIDE process is able to overcome past limitations in glass drilling and micro machining as it combines very high productivity and low manufacturing cost with the superior quality of a direct data process, forgoing masks or photo processing.

With the introduction of its new independent foundry service, LPKF is hoping to make the LIDE technology available on a much wider scale, covering both prototyping and experimental applications as well as scalable mass production capacity. The service is aimed at the manufacturing of glass substrates for advanced IC and MEMS packaging as well as micro-machining of spacer wafers,microfluidics and other specialty glass applications. LPKF’s new foundry service is located at its corporate headquarters and will operate under the company’s Vitrion brand name.

Established in 1976, LPKF Laser & Electronics manufactures laser systems used in circuit board prototyping, microelectronics fabrication, solar panel scribers, laser plastic welding systems and recently added a foundry service for thin glass substrates used in electronics packaging. LPKF’sworldwide headquarters is located in Hannover, Germany and its North American headquarters resides in Portland, OR.

The piezoelectric materials that inhabit everything from our cell phones to musical greeting cards may be getting an upgrade thanks to work discussed in the journal Nature Materials released online Jan 21.

Xiaoyu ‘Rayne’ Zheng, assistant professor of mechanical engineering in the College of Engineering, and a member of the Macromolecules Innovation Institute, and his team have developed methods to 3D print piezoelectric materials that can be custom-designed to convert movement, impact and stress from any directions to electrical energy.

“Piezoelectric materials convert strain and stress into electric charges,” Zheng explained.

A printed flexible sheet of piezoelectric smart material. Credit: Photo by H. Cui of the Zheng Lab

The piezoelectric materials come in only a few defined shapes and are made of brittle crystal and ceramic – the kind that require a clean room to manufacture. Zheng’s team has developed a technique to 3D print these materials so they are not restricted by shape or size. The material can also be activated – providing the next generation of intelligent infrastructures and smart materials for tactile sensing, impact and vibration monitoring, energy harvesting, and other applications.

Unleash the freedom to design piezoelectrics

Piezoelectric materials were originally discovered in the 19th century. Since then the advances in manufacturing technology has led to the requirement of clean-rooms and a complex procedure that produces films and blocks which are connected to electronics after machining. The expensive process and the inherent brittleness of the material, has limited the ability to maximize the material’s potential.

Zheng’s team developed a model that allows them to manipulate and design arbitrary piezoelectric constants, resulting in the material generating electric charge movement in response to incoming forces and vibrations from any direction, via a set of 3D printable topologies. Unlike conventional piezoelectrics where electric charge movements are prescribed by the intrinsic crystals, the new method allows users to prescribe and program voltage responses to be magnified, reversed or suppressed in any direction.

“We have developed a design method and printing platform to freely design the sensitivity and operational modes of piezoelectric materials,” Zheng said. “By programming the 3D active topology, you can achieve pretty much any combination of piezoelectric coefficients within a material, and use them as transducers and sensors that are not only flexible and strong, but also respond to pressure, vibrations and impacts via electric signals that tell the location, magnitude and direction of the impacts within any location of these materials.”

3D printing of piezoelectrics, sensors and transducers

A factor in current piezoelectric fabrication is the natural crystal used. At the atomic level, the orientation of atoms are fixed. Zheng’s team has produced a substitute that mimics the crystal but allows for the lattice orientation to be altered by design.

“We have synthesized a class of highly sensitive piezoelectric inks that can be sculpted into complex three-dimensional features with ultraviolet light. The inks contain highly concentrated piezoelectric nanocrystals bonded with UV-sensitive gels, which form a solution – a milky mixture like melted crystal – that we print with a high-resolution digital light 3D printer,” Zheng said.

The team demonstrated the 3D printed materials at a scale measuring fractions of the diameter of a human hair. “We can tailor the architecture to make them more flexible and use them, for instance, as energy harvesting devices, wrapping them around any arbitrary curvature,” Zheng said. “We can make them thick, and light, stiff or energy-absorbing.”

The material has sensitivities 5-fold higher than flexible piezoelectric polymers. The stiffness and shape of the material can be tuned and produced as a thin sheet resembling a strip of gauze, or as a stiff block. “We have a team making them into wearable devices, like rings, insoles, and fitting them into a boxing glove where we will be able to record impact forces and monitor the health of the user,” said Zheng.

“The ability to achieve the desired mechanical, electrical and thermal properties will significantly reduce the time and effort needed to develop practical materials,” said Shashank Priya, associate VP for research at Penn State and former professor of mechanical engineering at Virginia Tech.

New applications

The team has printed and demonstrated smart materials wrapped around curved surfaces, worn on hands and fingers to convert motion, and harvest the mechanical energy, but the applications go well beyond wearables and consumer electronics. Zheng sees the technology as a leap into robotics, energy harvesting, tactile sensing and intelligent infrastructure, where a structure is made entirely with piezoelectric material, sensing impacts, vibrations and motions, and allowing for those to be monitored and located. The team has printed a small smart bridge to demonstrate its applicability to sensing the locations of dropping impacts, as well as its magnitude, while robust enough to absorb the impact energy. The team also demonstrated their application of a smart transducer that converts underwater vibration signals to electric voltages.

“Traditionally, if you wanted to monitor the internal strength of a structure, you would need to have a lot of individual sensors placed all over the structure, each with a number of leads and connectors,” said Huachen Cui, a doctoral student with Zheng and first author of the Nature Materials paper. “Here, the structure itself is the sensor – it can monitor itself.”

By Serena Brischetto

SEMI met with Jay Zhang, business development director at Corning Incorporated, to discuss recent innovations at Corning that allow fine granularity CTE engineering as well as high Young’s modulus. We also talked about the impact of this work on in-process warp control, as well as the associated production methodology that provides rapid prototyping and high-volume manufacturing. We spoke ahead of his presentation at the 3D & Systems Summit, 28-30 January, 2019, in Dresden, Germany. To register for the event, please click here.

SEMI: What is Corning’s mission and vision and your role within the company?

Zhang: Corning is one of the world’s leading innovators in materials science with a track record of 165+ years of life-changing innovations. We excel in glass science, ceramics science, and optical physics and succeed through sustained investment in RD&E. Our products include Corning® Gorilla® glass, a durable material used on more than six billion mobile devices worldwide, and industry-leading LCD glass for display applications.

We have recently dedicated a unit of the company called Precision Glass Solutions to address the emerging need for glass in the semiconductor industry. Here we apply Corning’s long history of glass science expertise and deep customer relationships in consumer electronics to support cutting-edge applications like wafer-level optics for precise 3D sensing and carrier solutions for temporary bonding applications in semiconductor manufacturing. It’s our most recent work in the Carrier Solutions product line that I’m excited to present: a new carrier glass product optimized for fan-out, called Corning Advanced Packaging Carriers.

SEMI: What projects are you currently working on that you think will make a difference in 2019?

Zhang: My team is excited to introduce Corning Advanced Packaging Carriers this year. This is a new line of product within our portfolio of Carrier Solutions. These ultra-flat glass carriers are specially developed to reduce customers’ challenge of in-process warp by up to 40 percent, which in turn helps advanced packaging customers achieve better yield.

Corning Advanced Packaging Carriers feature high-stiffness properties and are available in a wide range of coefficients of thermal expansion (CTE) in fine granularity. These attributes help customers select an ideal glass carrier that will minimize in-process warp for their package. Furthermore, we make sample quantities of these carriers available in just four to six weeks to help maximize efficiency during customers’ R&D process.

My team is excited about the potential of this new product, but also encouraged by our results. We have already supplied this product and have heard from one of the largest semiconductor companies in Taiwan that it has reduced in-process warp by as much as 150μm.

SEMI: Your presentation at the 3D & Systems Summit will focus on Agile Manufacturing of Glass Carriers for Advanced Packaging. What exactly will you be sharing?

Zhang: There is a lot of interest right now in using glass as a carrier substrate in temporary bonding applications in advanced semiconductor packaging – especially in fan-out processes. We also know that in-process warp is a significant challenge to companies pursuing advanced packaging because different CTE materials are added during the process.

My team has done a lot of work to understand the impact that an ideal CTE glass carrier substrate can have on minimizing in-process warp. We have studied the available levers – both theoretical and in real-life fab environments – that can help address this challenge. I will present our findings on how it is possible to select a glass carrier with the ideal CTE and Young’s modulus to reduce in-process warp by up to 40 percent, and how Corning has developed an agile manufacturing platform to support customers with these ideal carriers from their R&D stage through mass production.

SEMI: What do you think will be a hot topic in the next few years?

Zhang: We expect high-end fanout technology to address more applications beyond just mobile APs. There is also an interesting dynamic playing out between wafer-level and panel-level fan-out technologies. Corning is active in both areas. In developing and offering high performance glass carriers, we hope to help enable our customers to expand the fan-out applications space.

SEMI: What are your expectations regarding the summit in Dresden, and why do you recommend your members and other industry leaders to attend the 2019 3D & Systems Summit?

Zhang: Europe is where some of the most advanced packaging technologies are born. Fan-out also saw early commercialization there. I hope to meet many scientists and technologists at 3D & Systems Summit and exchange technical and business ideas. We also hope to get early feedback from other attendees about the value of our new product offering.

Serena Brischetto is a marketing and communications manager at SEMI Europe.

This originally appeared on the SEMI blog.

Corning Incorporated (NYSE: GLW) today introduced its latest breakthrough in glass substrates for the semiconductor industry – Advanced Packaging Carriers. This enhanced line of glass carrier wafers is optimized for fan-out processes, a type of cutting-edge semiconductor packaging that enables smaller, faster chips for consumer electronics, automobiles, and other connected devices.

Corning Advanced Packaging Carriers feature three significant improvements:

– Fine granularity in a wide range of available coefficients of thermal expansion (CTE)
– High stiffness composition
– Rapid sampling availability

These attributes are important for customers pursuing fan-out packaging because:

– Fine granularity enables customers to more easily select the optimal CTE needed to minimize in-process warp. Precise CTE offerings thereby help reduce customers’ development cycle time.
– Corning’s high stiffness compositions help further reduce in-process warp. Minimizing warp helps maximize their yield of packaged chips.
– Rapid sampling availability also contributes to reduced development time and enables customers to move to the mass production phase more quickly.

“We created Corning Advanced Packaging Carriers especially for our customers pursuing the most challenging types of chip manufacturing processes,” said Rustom Desai, commercial director of Corning Precision Glass Solutions.

“Our deep technical ties in the semiconductor industry, combined with Corning’s core competencies in glass science and manufacturing, enabled us to create an innovative product that can help customers maximize efficiency throughout their development process and mass production ramp,” Desai said.

Corning’s semiconductor glass carriers are one of several products in Corning’s portfolio of Precision Glass Solutions designed to address the emerging need for glass across microelectronics. This portfolio provides customers with a one-stop shop for world-class capabilities including proprietary glass and ceramic manufacturing platforms, finishing processes, bonding technologies, best-in-class metrology, automated laser glass-processing, and optical design expertise.