Abstract-Sub-cycle control of terahertz high-harmonic generation by dynamical Bloch oscillations

• O. Schubert,
• M. Hohenleutner,
• F. Langer,
• B. Urbanek,
• C. Lange,
• U. Huttner,
• D. Golde,
• T. Meier,
• M. Kira,
• S. W. Koch
• & R. Huber
• • http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2013.349.html

Ultrafast charge transport in strongly biased semiconductors is at the heart of high-speed electronics, electro-optics and fundamental solid-state physics^{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}. Intense light pulses in the terahertz spectral range have opened fascinating vistas^{14, 15, 16, 17, 18,19, 20, 21}. Because terahertz photon energies are far below typical electronic interband resonances, a stable electromagnetic waveform may serve as a precisely adjustable bias^{5, 11, 17, 19}. Novel quantum phenomena have been anticipated for terahertz amplitudes, reaching atomic field strengths^8, 9, 10. We exploit controlled (multi-)terahertz waveforms with peak fields of 72 MV cm⁻¹ to drive coherent interband polarization combined with dynamical Bloch oscillations in semiconducting gallium selenide. These dynamics entail the emission of phase-stable high-harmonic transients, covering the entire terahertz-to-visible spectral domain between 0.1 and 675 THz. Quantum interference of different ionization paths of accelerated charge carriers is controlled via the waveform of the driving field and explained by a quantum theory of inter- and intraband dynamics. Our results pave the way towards all-coherent terahertz-rate electronic

TeTechS blog-Terahertz Technology for Microelectronic Package Fault Isolation and Failure analysis

Terahertz Technology for Microelectronic Package Fault Isolation and Failure analysis

Posted by Daniel Hailu on Friday, 13 December 2013 in Terahertz

http://www.tetechs.com/blog/index.php/entry/terahertz-technology-for-microelectronic-package-fault-isolation-and-failure-analysis

Electro-optical terahertz pulse reflectometry (EOTPR), an electro-optical system driven by an ultrafast laser source, was introduced recently to isolate faults and detect defects in advanced IC packages.  The steadily growing complexity of integrated-circuit (IC) technology is pushing the available inspection and fault-analysis tools to their limits.  Among the nondestructive methods, time-domain reflectometry (TDR) is considered to be an exceptionally fast method for fault detection in electronic packages.  The EOTPR system provides 10 μm in distance accuracy that can be used to localize package-level open and short failures non-destructively.  Today’s TDR systems are generally all-electronic and use a step or pulse generator and a high-bandwidth oscilloscope as the main components.  The electromagnetic signal is transmitted through a high-frequency cable and a probe tip to the device under test (DUT).  Every discontinuity at the transmission path within the DUT causes a part of the injected signal to be reflected.  By monitoring these reflections in the time domain, it is possible to detect structural defects and distinguish functional from defective structures.  Terahertz technology enables high resolution fault isolation in advanced semiconductor packages and 3D imaging in integrated circuit devices.  An EOTPR system was used to determine the location of open and short failures and to identify impedance variations in a series of package substrates.  The experimental results demonstrate the higher accuracy of the EOTPR system in determining the distance to defect compared to traditional time-domain reflectometry systems.  

(Source TeraView:  Using Terahertz pulses for fault analysis)

A first femtosecond-laser-driven optoelectronic TDR system for fault isolation was recently introduced by Intel (Santa Clara, CA).  With this system, a substantial improvement over all-electronic systems was achieved with τrise = 5.7 ps. However, a main bottleneck within this system, which prevents utilizing the full benefits of optoelectronic sub-picosecond-range switching speeds is brought about due to the waveguide and probe components that are required for signal transmission between the optoelectronic pulse-generation and detection devices and the DUT.  Frequencies above 110 GHz are not transmitted by these components, and hence the majority of resolution power is lost within the TDR system.  Nagel et al., Opt. Expr., 19, 12509–12514 (2011) and using Terahertz reflectometry imaging to find faults in silicon chips have recently demonstrated this bottleneck can now be effectively eliminated by novel micromachined probe tips applied for broadband photoconductive (PC) pulse generation and detection immediately at the DUT.  A TDR signal rise time of τrise = 1.1 ps has been achieved by this advanced optoelectronic system.  In contrast to earlier configurations, the probes can also be used in a contact-free mode through capacitive probe/waveguide coupling.

Fast Fault Isolation and Analysis in Advanced Semiconductor Packages now possible with Terahertz Time Domain Reflectometry

Image by Getty Images via @daylife

TeraView Cambridge, United Kingdom – 14th July 2010

TeraView (http://www.teraview.com/), working with the Intel Corporation, has developed a next generation Terahertz (THz) Time Domain Reflectometry (TDR) Failure Analysis (FA) tool to enable high resolution fault isolation in Advanced and 3D semiconductor packages. Intel refers to the new technique as Electro Optical Terahertz Pulse Reflectometry, or EOTPR. The technique was pioneered by Yongming Cai, Zhiyong Wang, Rajen Dias, and Deepak Goyal at Intel’s ATD QR Laboratory.

The technique, which utilises TeraView’s proprietary Terahertz Pulse technology (TPITM), isolates faults on interconnects to within 10 microns, enabling production and quality issues to be rapidly identified and addressed. The tool reduces failure analysis times from days to minutes and enables fault isolation in packages where conventional FA tools have failed.

The need for Advanced and 3D semiconductor packaging is being driven by the requirements of the mobile phone and consumer electronics industries, which aim to overcome limitations in integrated circuit form, functionality, and speed associated with conventional packaging. TeraView’s tool provides a unique capability which aids in the design and production of current and future generations of advanced packages, including complex wire-bonded, flip chip, and 3D packages as well as those utilizing new techniques such as Through Silicon Vias (TSVs).

Intel said in a recent paper presented at the ECTC Conference in Las Vegas

‘With such a revolutionary concept, innovative design and superior performance, EOTPR will become an essential tool for microelectronic package fault isolation and failure analysis. By integrating EOTPR with other techniques such as 3D X-Ray in the FA flow, FA TPT and success rate can be dramatically improved. Fully automated systems can be developed for component, board and solder joint quality screening.’

Dr Don Arnone, TeraView’s CEO added ‘We are delighted to have successfully delivered a new product in close collaboration with the Intel Corporation. The importance of this new tool in both the development and the manufacture of advanced semiconductor devices has been identified and proven by our collaborators at Intel. The new product adds to TeraView’s growing track record of world firsts and opens up a very significant market opportunity for our technology’