Use of a Solid Immersion Lens for Thermal IR Imaging

Author(s):  
O. Breitenstein ◽  
F. Altmann ◽  
T. Riediger ◽  
D. Karg ◽  
V. Gottschalk

Abstract A hemispherical silicon solid immersion lens (SIL) was used to improve the spatial resolution of front-side thermal IR imaging in lock-in mode. The bottom of the SIL was coneshaped to reduce the footprint of the SIL to the size of the imaged region. Caused by the lock-in operation mode, the detection limit improves by 2-3 orders of magnitude, and scattered light does not limit the image contrast. By using this SIL in combination with an IR camera working in the 3-5 μm wavelength range, a spatial resolution of 1.4 μm was obtained for thermal IR imaging. An automatic SIL positioning facility was constructed to place the SIL exactly in the center of the imaged region and to easily remove it after the detailed investigation.

Author(s):  
O. Breitenstein ◽  
J.P. Rakotoniaina ◽  
F. Altmann ◽  
J. Schulz ◽  
G. Linse

Abstract In this paper new thermographic techniques with significant improved temperature and/or spatial resolution are presented and compared with existing techniques. In infrared (IR) lock-in thermography heat sources in an electronic device are periodically activated electrically, and the surface is imaged by a free-running IR camera. By computer processing and averaging the images over a certain acquisition time, a surface temperature modulation below 100 µK can be resolved. Moreover, the effective spatial resolution is considerably improved compared to stead-state thermal imaging techniques, since the lateral heat diffusion is suppressed in this a.c. technique. However, a serious limitation is that the spatial resolution is limited to about 5 microns due to the IR wavelength range of 3 -5 µm used by the IR camera. Nevertheless, we demonstrate that lock-in thermography reliably allows the detection of defects in ICs if their power exceeds some 10 µW. The imaging can be performed also through the silicon substrate from the backside of the chip. Also the well-known fluorescent microthermal imaging (FMI) technique can be be used in lock-in mode, leading to a temperature resolution in the mK range, but a spatial resolution below 1 micron.


2006 ◽  
Vol 46 (9-11) ◽  
pp. 1508-1513 ◽  
Author(s):  
O. Breitenstein ◽  
F. Altmann ◽  
T. Riediger ◽  
D. Karg ◽  
V. Gottschalk

Author(s):  
A.C.T. Quah ◽  
S.H. Goh ◽  
V.K. Ravikumar ◽  
S.L. Phoa ◽  
V. Narang ◽  
...  

Abstract The spatial resolution and sensitivity of laser induced techniques are significantly enhanced by combining refractive solid immersion lens technology and laser pulsing with lock-in detection algorithm. Laser pulsing and lock-in detection enhances the detection sensitivity and removes the ‘tail’ artifacts due to amplifier ac-coupling response. Three case studies on microprocessor devices with different failure modes are presented to show that the enhancements made a difference between successful and unsuccessful defect localization.


2008 ◽  
Vol 683 (2) ◽  
pp. L171-L174 ◽  
Author(s):  
John P. Wisniewski ◽  
Mark Clampin ◽  
Karen S. Bjorkman ◽  
Richard K. Barry

Author(s):  
Fei Long Xu ◽  
Phoumra Tan ◽  
Dan Nuez

Abstract Physical FA innovations in advanced flip-chip devices are essential, especially for die-level defects. Given the increasing number of metal layers, traditional front-side deprocessing requires a lot of work on parallel lapping and wet etching before reaching the transistor level. Therefore, backside deprocessing is often preferred for checking transistor-level defects, such as subtle ESD damage. This paper presents an efficient technique that involves precise, automated die thinning (from 760µm to 5µm), high-resolution fault localization using a solid immersion lens, and rigorous KOH etch. Using this technique, transistor-level damage was revealed on advanced 7nm FinFET devices with flip-chip packaging.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3480 ◽  
Author(s):  
Kunpeng Feng ◽  
Jiwen Cui ◽  
Yihua Jin ◽  
Xun Sun ◽  
Dong Jiang ◽  
...  

A novel optical frequency domain reflectometer (OFDR) processing algorithm is proposed to enhance the measurable range and data processing rate using a narrow swept spectrum range and reducing the time consuming of the process distributed sensing results. To reduce the swept wavelength range and simultaneously enhance strain measurable range, the local similarity characteristics of Rayleigh scattering fingerprint spectrum is discovered and a new similarity evaluation function based on least-square method is built to improve the data processing rate and sensing performance. By this method, the strain measurable range is raised to 3000 µε under a highest spatial resolution of 3 mm when the swept spectrum range is only 10 nm and the data processing rate is improved by at least 10 times. Experimental results indicate that a nonlinearity of less than 0.5%, a strain resolution of better than 10 µε, a repeatability at zero strain of below ±0.4 GHz and a full-scale accuracy is lower than 0.85 GHz under a highest spatial resolution of 3 mm can be achieved. Advantages of this method are fast processing rate, large strain measurable range, high SNR, and applicability with current OFDR systems.


2005 ◽  
Vol 886 ◽  
Author(s):  
Peter M. Mayer ◽  
Rajeev J. Ram

ABSTRACTThis paper presents the first cross-plane thermoreflectance image of the temperature distribution in a thermoelectric (TE) element under bias. Using the technique of lock-in CCD thermoreflectance imaging, we can map the temperature distribution of an operational device with submicron spatial resolution and a temperature resolution of 10 mK. As such it offers a complete picture of the quasi-equilibrium transport within the device. The submicron resolution of the thermoreflectance image enables clear determination of localized heating due at interfaces - for example to due contact resistance - and thermal impedance mismatch within samples. The high spatial resolution is ideal for the characterization of thin-film thermoelectric materials where data from conventional techniques (such as the transient Harman method) are difficult to interpret. This paper also presents the first thermoreflectance data we are aware of for BiTe-based material systems. Identification and separation of the Peltier and Joule components of the heating are possible, and finite difference simulations of the devices are presented for comparison with experiment. In this way it is possible to simultaneously acquire information about the Seebeck coefficient, electrical conductivity, and thermal conductivity of the thermoelectric material. The measurements demonstrate the feasibility of non-contact thermal measurements at the sub-micron scale.


2011 ◽  
Vol 148-149 ◽  
pp. 1045-1050
Author(s):  
Zhi Ying Wu ◽  
Yi Zhang ◽  
Zuo Yuan Shen

Improving spectrometer detection limit using statistical principle and signal-processing technique are described simply in this work. In the detection of gas photoacoustic(PA) signal, accurate partitions of the sampled data affect on the detection limit to some extent although Lock-in amplification technique with high SNR and microphone sensor with high sensitivity have been used. A model and the resulting algorithm are proposed from PA-signal samples. The techniques are validated at ppb level on PA spectrometer for NH3 breath detection in high concentration of CO2 and H2O based on tunable erbium-doped fiber laser (TEDFL) or for multicomponent trace gas detection based on waveguide CO2 laser or on other laser source.


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