HRL Interposer Enables Pixel Fan-Out and Curved Sensor Stacking

HRL Laboratories' additive manufacturing team demonstrates 3D-printed interposers with previously impossible slanted and curved vias with diameters of less than 10µm. Vias are small openings in insulating layers of integrated circuits that allow conductive connections.

HRL is now 3D printing vias in polymer and ceramic materials with 2 µm resolution, allowing for complex routing. The vias are then metallized to electrically connect different devices and integrated circuits.

“We have printed arrays of straight and curved vias with an aspect ratio of at least 200:1. There is still room to increase this ratio using the low-viscosity preceramic resin that we developed in house,” said HRL Lead Engineer Kayleigh Porter.

HRL Laboratories’ development effort is currently funded by DARPA’s Microsystems Technology Office under the Focal arrays for Curved Infrared Imagers (FOCII) program.

SPAD Size Scaling Trade-offs

EPFL and Canon publish an MDPI paper "A Scaling Law for SPAD Pixel Miniaturization" by Kazuhiro Morimoto and Edoardo Charbon.

"The growing demands on compact and high-definition single-photon avalanche diode (SPAD) arrays have motivated researchers to explore pixel miniaturization techniques to achieve sub-10 um pixels. The scaling of the SPAD pixel size has an impact on key performance metrics, and it is, thereby, critical to conduct a systematic analysis of the underlying tradeoffs in miniaturized SPADs. On the basis of the general assumptions and constraints for layout geometry, we performed an analytical formulation of the scaling laws for the key metrics, such as the fill factor (FF), photon detection probability (PDP), dark count rate (DCR), correlated noise, and power consumption. Numerical calculations for various parameter sets indicated that some of the metrics, such as the DCR and power consumption, were improved by pixel miniaturization, whereas other metrics, such as the FF and PDP, were degraded. Comparison of the theoretically estimated scaling trends with previously published experimental results suggests that the scaling law analysis is in good agreement with practical SPAD devices. Our scaling law analysis could provide a useful tool to conduct a detailed performance comparison between various process, device, and layout configurations, which is essential for pushing the limit of SPAD pixel miniaturization toward sub-2 um-pitch SPADs."

Sony Thailand Image Sensor Production Center to Run on 100% Renewable Energy

Sony Device Technology Center in Thailand is taking on a challenge of becoming the first Sony Group manufacturing site in Southeast Asia to operate its facilities using 100% renewable energy. The Center is mainly responsible for the assembly of image sensors.

Sony Device Technology has a roof area of about 50,000 square meters, and plans to cover this surface almost entirely with solar panels by October of this year. The solar panels will be installed on an area approximately 2.54 times the ground area of the Tokyo Dome, which would make it the largest area covered by solar panels at any facility managed by the Sony Group. Some of the panels have already started generating electricity, and by the end of the fiscal year, all of the large panels will be generating electricity to supply the plant. Although these panels alone will not be able to supply all of the electricity required by the facility, they will be able to reduce CO2 emissions by purchasing Renewable Energy Certificates, and by combining solar panels with the purchase of Renewable Energy Certificates, Sony Device Technology expects to become the first Sony Group manufacturing site in Asia to achieve 100% renewable energy operation by the end of this fiscal year.

APD with Photon Trapping

University of California – Davis and W&WSens Devices publish a paper "Avalanche Photodetectors with Photon Trapping Structures for Biomedical Imaging Applications" by Cesar Bartolo-Perez, Soroush Ghandiparsi, Ahmed S. Mayet, Hilal Cansizoglu, Yang Gao, Wayesh Qarony, Ahasan Ahamed, Shih-Yuan Wang, Simon R. Cherry, M. Saif Islam, and Gerard Arino-Estrada.

"In this work, we evaluate the gain, detection efficiency, and timing performance of avalanche photodiodes (APD) with photon trapping nanostructures for photons with 450 and 850 nm wavelengths. At 850 nm wavelength, our photon trapping avalanche photodiodes showed 30 times higher gain, an increase from 16% to >60% enhanced absorption efficiency, and a 50% reduction in the full width at half maximum (FWHM) pulse response time close to the breakdown voltage. At 450 nm wavelength, the external quantum efficiency increased from 54% to 82%, while the gain was enhanced more than 20-fold. Therefore, silicon APDs with photon trapping structures exhibited a dramatic increase in absorption compared to control devices. Results suggest very thin devices with fast timing properties and high absorption between the near-ultraviolet and the near infrared region can be manufactured for high-speed applications in biomedical imaging. This study paves the way towards obtaining single photon detectors with photon trapping structures with gains above 10^6 for the entire visible range."

Microsoft Expands its iToF Alliances with Orbbec, LG Innotek, Tempo, SpeedCargo, AgentFactory

Microsoft Azure Depth Platform keeps expanding its iToF platform and announces more customers and adopters:

Orbbec: Orbbec is partnering with Microsoft to develop a new series of high-performance 3D cameras that can run advanced depth vision algorithms using onboard computing to convert raw data into precise depth images. The camera will connect to Azure cloud, and leverage device management, data streaming and AI analytics capabilities. Designed for advanced human/machine interface, robotics, 3D scanning and surveillance use as well as gaming and other consumer applications, the first camera is expected to debut in early 2022. (PRNewswire)

LG Innotek: Daniel Bar, head of business incubation for the Silicon & Sensor's group at Microsoft, said, "LG Innotek brings world class manufacturing expertise in complex optoelectronic systems. We are excited to welcome LG Innotek to our ecosystem and accelerate time to market for 3D cameras. This is a key step towards providing easy access for computer vision developers to create 3D vision applications."

Tempo — the first home fitness system that uses 3D sensors and A.I. to analyze your motion and provide real-time rep counting.

SPEEDCARGO with Microsoft’s Azure Depth Platform program aims to disrupt the air cargo and logistics industry with advanced 3D vision technologies.

Agent Factory leverages 3D sensing technologies by Microsoft in its AI solutions to advance automation, digitalization and optimization of logistics operations.

ResearchInChina Reports about LiDAR Adoption in Chinese Cars

ResearchInChina publishes "Global and China Automotive LiDAR Industry Report, 2021." Few quotes:

"At the 2021 Shanghai Auto Show, Huawei shocked all automakers and suppliers. Huawei has directly and indirectly supported more than 10,000 engineers in the R&D of intelligent automobiles. Except production, Huawei covers almost all of aspects required for digital transformation of automobiles: automotive perception and decision-making, network communications, electric drive, batteries, electric control, cloud-road networks outside vehicles, R&D and marketing.

Compared with the previous R&D investment involved with 1,000 persons (such as Baidu), Huawei's R&D team consisting of 10,000 persons has greatly accelerated the upgrade pace of intelligent networking of China's auto industry. When other countries around the world are still worrying about the pandemic, China will enter the era of leading the development of global automotive intelligent networking from 2021.

Take LiDAR installation as an example, the new models with LiDAR mainly come from domestic automakers."

"As L4 technical solutions are gradually applied to L2-L3 models, LiDAR has been installed widely. LiDAR is currently available on production cars, and is mainly used to enhance ADAS functions and make new cars more appealing.

So far, domestic OEMs prefer to adopt hybrid solid-state LiDAR (including rotating mirror, prism, MEMS) solutions, mainly because:

First, it is easier to reduce the costs of hybrid solid-state LiDAR than mechanical LiDAR. Compared with pure solid-state (OPA, Flash) LiDAR, hybrid solid-state LiDAR technology is relatively mature and easier to commercialize.

Second, the Rotating Mirror Solution (represented by Valeo) is the first technical solution that meets National Automotive Standards and the performance requirements of automakers, and can be supplied in batches with controllable costs."

Note: The first two pictures are taken from SystemPlus.fr reports without permission:

Depth from Chromatic Aberrations

OSA Optics Express publishes KAIST paper "Compact and fast depth sensor based on a liquid lens using chromatic aberration to improve accuracy" by Gyu Suk Jung and Yong Hyub Won.

"Depth from defocus (DFD) obtains depth information using two defocused images, making it possible to obtain a depth map with high resolution equal to that of the RGB image. However, it is difficult to change the focus mechanically in real-time applications, and the depth range is narrow because it is inversely proportional to the depth accuracy. This paper presents a compact DFD system based on a liquid lens that uses chromatic aberration for real-time application and depth accuracy improvement. The electrical focus changing of a liquid lens greatly shortens the image-capturing time, making it suitable for real-time applications as well as helping with compact lens design. Depth accuracy can be improved by dividing the depth range into three channels using chromatic aberration. This work demonstrated the improvement of depth accuracy through theory and simulation and verified it through DFD system design and depth measurement experiments of real 3D objects. Our depth measurement system showed a root mean square error (RMSE) of 0.7 mm to 4.98 mm compared to 2.275 mm to 12.3 mm in the conventional method, for the depth measurement range of 30 cm to 70 cm. Only three lenses are required in the total optical system. The response time of changing focus by the liquid lens is 10 ms, so two defocused images for DFD can be acquired within a single frame period of real-time operations."

IC Insights: CMOS Sensor Sales to Grow 2x from 2020 to 2025

IC Insights: The high-flying market for CMOS image sensors hit a speed bump in 2020 with the global outbreak of the Covid-19 virus crisis significantly cutting sales growth in this large optoelectronics product category to 3% last year compared to an annual average of nearly 16% since 2010.

When the Covid-19 virus pandemic accelerated in the first half of 2020, businesses, schools, travel, and most public activities were shut down worldwide, causing a nosedive in CMOS image sensor applications—including smartphones, automobiles, and a wide range of embedded cameras, which are increasingly used in commercial and industrial systems.  It ended up that 2020 was Sony’s worst year for image sensor growth since it began emphasizing CMOS technology over CCDs in 2006.

With the global economy expected to regain momentum in 2021 and more digital cameras being designed into systems—including new 5G smartphones and machine-vision applications, sales of CMOS image sensors are projected to increase by a compound annual growth rate (CAGR) of 12.0%, reaching $33.6 billion in 2025.  Total shipments of CMOS image sensors are forecast to grow by a CAGR of 14.9% to 13.5 billion units in 2025 compared to 6.7 billion in 2020.

The automotive systems are said to be the fastest growing application for CMOS image sensors in the next five years, with sales rising by CAGR of 33.8% to reach $5.1 billion in 2025.  After that, the highest sales growth rates in the five-year forecast are:  medical and scientific systems (a CAGR of 26.4% to $1.8 billion); security (a CAGR of 23.2% to $3.2 billion); and industrial, including robots and the Internet of Things (a CAGR of 21.8% to $3.5 billion).  CMOS image sensor sales for cellphones—the largest end-use application—are forecast to grow by a CAGR of 6.3% to $15.7 billion in 2025, or about 47% of the market total versus 61% in 2020 ($11.6 billion).

ON Semi Hayabusa Sensor Animation

 ON Semi publishes a promotional animation video for its Hayabusa automotive sensor family:

Hynix Article on CIS Progress

EDN publishes SK Hynix article on image sensor progress that shows the company's iToF sensor, among many other things:

Omnivision to Announce 0.61um Pixel Sensor

SparrowNews quotes Chinese sources that Omnivision is about to announce OV60A sensor with 0.61um pixels.

The 1/2.8-inch 60MP OV60A is the world’s first 0.61um image sensor for mobile phone front and rear cameras. The four-in-one CFA allows near-pixel merging to deliver 15MP images with 4x the sensitivity, providing the equivalent performance of 1.22 microns for preview and native 4K video, with the additional pixels needed for EIS.

The sensor also supports a low-power mode for “always-on” sensing, which saves battery life when used in conjunction with the phone’s artificial intelligence features. The “always-on” low power modes include ambient light sensing for wake-up and low power streaming mode. The sensor also supports dual I/O voltage rails (1.8V and 1.2V) and a CPHY interface.

Here is a timeline for the renewed pixel size race:

• 1.1um in 2010 (Omivision BSI-2, presented at MWC in Barcelona)
• 1.0μm in 2015 (Samsung S5K3P3, samples started in 2014)
• 0.9μm in 2017 (Samsung Slim 2X7)
• 0.8μm in 2018 (Sony IMX586)
• 0.7μm in 2019 (Samsung Slim GH1)
• 0.64um in 2021 (Samsung presentation at ISSCC, if conference presentations count)
• 0.61μm in 2021 (Omnivision OV60A)