Low-coherence interferometric absolute distance gauge for study of MEMS structures

Walecki, W. J.; Lai, Kevin; Pravdivtsev, Alexander; Souchkov, Vitali; Van, Phuc; Azfar, Talal; Wong, Theodore M.; Lau, S. H.; Koo, Ann

doi:10.1117/12.590013

Cited by 14 publications

(14 citation statements)

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“…This measurement method here and after is called single probe measurement. Another available measurement method is the dual probe mode [3,4], when two interferometers are located on different parts of the sample (top and bottom). Each interferometer measures a distance from the probe to the sample's surface and the distance between the two probes is calibrated.…”

Section: A Infra-red Interferometermentioning

confidence: 99%

Use of optical metrology for wafer level packaging of CMOS image sensor

Cunff

Pravdivtsev

Chao

et al. 2010

2010 IEEE International 3D Systems Integration Conference (3DIC)

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For WLP and 3D integration, wafers are processed through several steps which generally include bounding and thinning processes. Those processes are generally realized by the use of carriers typically glass or Silicon substrates. In this paper, we present results about thickness measurements using optical techniques namely Infra-Red interferometer and white-light spectrometer on various stacked structures. These non contact optical techniques are demonstrated to be helpful methods for the in-line monitoring.

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Section: A Infra-red Interferometermentioning

confidence: 99%

Use of optical metrology for wafer level packaging of CMOS image sensor

Cunff

Pravdivtsev

Chao

et al. 2010

2010 IEEE International 3D Systems Integration Conference (3DIC)

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“…We have reported earlier practical MEMS metrology applications where low coherence interferometers allowed practical study of the dimensional characteristics of very high aspect ratio structures such as deep and narrow trenches [11], [12], and thin membranes [10], [13]. Even though this metrology is a powerful solution for most of applications it suffers from certain fundamental limitations.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the fact that this method does not require access from both sides of the wafer fiber optic low coherence interferometers became popular tools for monitoring wafer thickness during grinding process in failure analysis laboratories [7]. Recently the same technology found interesting practical applications in compound semiconductor [8], [9], photonics [9], and micro-electromechanical system (MEMS) applications [10], [11], [12], [13].…”

Section: Introductionmentioning

confidence: 99%

Combined low-coherence interferometry and spectrally resolved reflectometry for nondestructive characterization of small-diameter high-aspect ratio micro-fabricated and micro-machined structures and multilayer membranes

Walecki¹,

Azfar²,

Pravdivstev³

et al. 2006

Micromachining and Microfabrication Process Technology XI

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We propose novel tool employing both low coherence interferometer and spectrally resolved reflectometer sensor. We discuss application of this novel tool for measurements of the narrow high aspect ratio structures. We demonstrate that the visible reflectance spectrum of such structures allows us to extend range of interferometer to measure depth trenches with diameter from 2 µm to 1 mm, with reproducibility 10 nm -100 nm depending on range of the thin film thickness. We also present of this novel tool for measurement of ultra-thin coated pressure sensor membranes. Application of an auxiliary spectral reflectometer allows correcting for systematic errors of low coherence interferometer which can be as large as 1.5 -2 µm.

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“…OCT has been employed in industrial applications for wafer thickness and topography metrology [1]. Since the performance of a real-time imaging for OCT is very important for inspection applications that need immediate diagnosis, the high-speed parallel processing has been studied to reconstruct the OCT images and the GPU is an attractive hardware for functional OCT features as well [2]- [5].…”

Section: Introductionmentioning

confidence: 99%

GPU-Based Acceleration for 3D OCT Imaging

Jin¹,

Lee²,

Lee³

2017

Proceedings of the 2017 Asia International Conference on Quantitative InfraRed Thermography

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We designed a graphics processing unit (GPU)-based acceleration to reconstruct the optical coherence tomography (OCT) images as sub-micrometer resolution with the spectral domain OCT (SD-OCT) system. GPU-based acceleration is the use of general purpose GPU (GP-GPU) together with a CPU to accelerate the specific operation. As a result, by applying GPU acceleration to the tomographic inspection of biological samples, SD-OCT imaging can be obtained in excess of 40 frames per second (FPS) for the K6000 GPU-accelerated SD-OCT with frame size 4096 (axial) × 512 (lateral), and more than 512x512x500 volumes can be reconstructed with a speed increase of 7x or more (compared to a non-GPU).

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Low-coherence interferometric absolute distance gauge for study of MEMS structures

Cited by 14 publications

References 0 publications

Use of optical metrology for wafer level packaging of CMOS image sensor

Use of optical metrology for wafer level packaging of CMOS image sensor

Combined low-coherence interferometry and spectrally resolved reflectometry for nondestructive characterization of small-diameter high-aspect ratio micro-fabricated and micro-machined structures and multilayer membranes

GPU-Based Acceleration for 3D OCT Imaging

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