Novel low coherence metrology for nondestructive characterization of high-aspect-ratio microfabricated and micromachined structures

“…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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“…1, [2,[7][8][9][10][11]. It is a fiber optic implementation of low coherence Michelson interferometer [2].…”

Section: Introductionmentioning

confidence: 99%

Novel noncontact thickness metrology for backend manufacturing of wide bandgap light emitting devices

Walecki

Lai

Souchkov

et al. 2005

phys. stat. sol. (c)

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289 (1996) [2]). Purpose of this paper is to present an extension of this method to characterisation of ultra-thin compound wide bandgap wafers mounted on insulating carriers. We present alternative technique, which does not suffer from above discussed limitations, and can be easily integrated in the production tools, and provide accurate measurement of samples while they are being processed. IntroductionThe metrology of thin (0.1-0.2 mm) and ultra-thin (below 0.1 mm) semiconductor compound materials wafers has been identified very early as one of the technology gaps of the industry. The most commonly employed metrologies include capacitance and air pressure techniques. These two competing technologies have been proven to be reliable and quite accurate solutions for measurement of thickness, bow, warp and related parameters in relatively thick and well conducting materials.

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Novel low coherence metrology for nondestructive characterization of high-aspect-ratio microfabricated and micromachined structures

Cited by 15 publications

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High-speed high-accuracy fiber optic low-coherence interferometry for in situ grinding and etching process monitoring

High-speed high-accuracy fiber optic low-coherence interferometry for in situ grinding and etching process monitoring

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

Novel noncontact thickness metrology for backend manufacturing of wide bandgap light emitting devices

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