Scanning SQUID microscopy of integrated circuits

Chatraphorn, S.; Fleet, E. F.; Wellstood, F. C.; Knauss, L.A.; Eiles, Travis M.

doi:10.1063/1.126327

Cited by 79 publications

(34 citation statements)

References 5 publications

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“…While trapped atoms do not have the highest sensitivity to uniform magnetic fields, they are particularly well suited for making field measurements with high spatial resolution corresponding to the trap size, where vapor cells do not work well because spin-relaxation time quickly decreases with cell size. Such high resolution magnetic microscopes find a range of applications, from studies of magnetic domains [102] to imaging of currents on integrated circuits [103].…”

Section: E Magnetometery With Cold Atomsmentioning

confidence: 99%

Optical magnetometry

2007

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Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertialrotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.

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Section: E Magnetometery With Cold Atomsmentioning

confidence: 99%

Optical magnetometry

2007

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“…SQUID microscopy has been used for visualization of magnetic structures at 77 K with a spatial resolution of about 30 ä 10 -6 m in the vertical component of the magnetic field [28]. Still, recent research on scanning SQUID microscopy focus on room temperature samples, where the main developments target improvements in hardware or software to achieve better spatial resolution [26,27]. Fong et al were able to image magnetic fields of room-temperature samples with sub-millimeter resolution.…”

Section: Introductionmentioning

confidence: 97%

Magnetoresistive Sensors for Surface Scanning

Leitao¹,

Borme

Orozco

et al. 2013

Giant Magnetoresistance (GMR) Sensors

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Abstract. This chapter provides an overview on several techniques used for surface imaging, including SQUIDs, Hall-effect sensors, Giant magnetoimpedance sensors, and magnetoresistive (MR) sensors. Among all magnetic field sensors, only SQUIDs and MR devices have the potential to localize buried and non-visual field sources (such as defects in integrated circuits or magnetic field sources in biological environments. In particular, we describe how MR sensors have been used with advantage for integrated circuit (IC) mapping, with resolution below 500 nm and sensitivity to detect currents as low as 50 nA and have been used for many applications requiring low magnetic field detection. Challenges and experimental considerations on integration of MR sensors on a commercial analysis tool are provided here. Examples obtained with real devices demonstrate how Scanning Magnetic Microscopy has become an established failure analysis technique for visualizing current paths in microelectronic devices.

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“…SQUID microscopy is a powerful technique for imaging weak magnetic field distributions with the highest field sensitivity. A SQUID microscope allows samples of about 100 µm to be scanned at room temperature (Kirtley and Wikswo 1999;Chatraphorn et al 2000;Ono and Ishiyama 2004;Fong et al 2005). An important use of this technique is the study of geological samples (Fong et al 2005;Baudenbacher et al 2002Baudenbacher et al , 2003Wang et al 2014;Weiss et al 2000Weiss et al , 2007aOda et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Scanning SQUID microscope system for geological samples: system integration and initial evaluation

Oda

Kawai

Miyamoto

et al. 2016

Earth Planets Space

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We have developed a high-resolution scanning superconducting quantum interference device (SQUID) microscope for imaging the magnetic field of geological samples at room temperature. In this paper, we provide details about the scanning SQUID microscope system, including the magnetically shielded box (MSB), the XYZ stage, data acquisition by the system, and initial evaluation of the system. The background noise in a two-layered PC permalloy MSB is approximately 40-50 pT. The long-term drift of the system is approximately ≥1 nT, which can be reduced by drift correction for each measurement line. The stroke of the XYZ stage is 100 mm × 100 mm with an accuracy of ~10 µm, which was confirmed by laser interferometry. A SQUID chip has a pick-up area of 200 μm × 200 μm with an inner hole of 30 μm × 30 μm. The sensitivity is 722.6 nT/V. The flux-locked loop has four gains, i.e., ×1, ×10, ×100, and ×500. An analog-to-digital converter allows analog voltage input in the range of about ±7.5 V in 0.6-mV steps. The maximum dynamic range is approximately ±5400 nT, and the minimum digitizable magnetic field is ~0.9 pT. The sensor-to-sample distance is measured with a precision line current, which gives the minimum of ~200 µm. Considering the size of pick-up coil, sensor-to-sample distance, and the accuracy of XYZ stage, spacial resolution of the system is ~200 µm. We developed the software used to measure the sensor-to-sample distance with line scan data, and the software to acquire data and control the XYZ stage for scanning. We also demonstrate the registration of the magnetic image relative to the optical image by using a pair of point sources placed on the corners of a sample holder outside of a thin section placed in the middle of the sample holder. Considering the minimum noise estimate of the current system, the theoretical detection limit of a single magnetic dipole is ~1 × 10 −14 Am 2 . The new instrument is a powerful tool that could be used in various applications in paleomagnetism such as ultrafine-scale magnetostratigraphy and single-crystal paleomagnetism.

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Scanning SQUID microscopy of integrated circuits

Cited by 79 publications

References 5 publications

Optical magnetometry

Optical magnetometry

Magnetoresistive Sensors for Surface Scanning

Scanning SQUID microscope system for geological samples: system integration and initial evaluation

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