Overlay measurement using angular scatterometer for the capability of integrated metrology

Ko, Chun-Hung; Ku, Yi-Sha

doi:10.1364/oe.14.006001

Cited by 17 publications

(7 citation statements)

References 6 publications

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“…The Mueller matrices of the Si grating were calculated by the rigorous coupled-wave analysis (RCWA) [24][25][26] for each p (p ∈ Ω) and a in the spectral range of 200-800 nm with an increment of 10 nm. In the calculation of the covariance matrix C by equation (3), the variances of the Mueller matrix elements were obtained from a noise model given in our previous work [27], which were functions of the specific p and a. According to equation (8 Here, the parameter domain Ω was determined according to the structural parameter values measured by SEM.…”

Section: Resultsmentioning

confidence: 99%

“…Optical scatterometry, also referred to as optical critical dimension metrology, has become one of the most important techniques for critical dimension (CD) and overlay metrology in semiconductor industry due to its inherent speed, noncontact, nondestructive, and inexpensive merits over other techniques, such as scanning electron microscopy (SEM) and atomic force microscopy [1][2][3][4][5][6][7][8][9]. As a model-based metrology technique, the implementation of optical scatterometry involves two steps [10,11].…”

Section: Introductionmentioning

confidence: 99%

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Probing optimal measurement configuration for optical scatterometry by the multi-objective genetic algorithm

Chen

Jiang

et al. 2018

Meas. Sci. Technol.

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Measurement configuration optimization (MCO) is a ubiquitous and important issue in optical scatterometry, whose aim is to probe the optimal combination of measurement conditions, such as wavelength, incidence angle, azimuthal angle, and/or polarization directions, to achieve a higher measurement precision for a given measuring instrument. In this paper, the MCO problem is investigated and formulated as a multi-objective optimization problem, which is then solved by the multi-objective genetic algorithm (MOGA). The case study on the Mueller matrix scatterometry for the measurement of a Si grating verifies the feasibility of the MOGA in handling the MCO problem in optical scatterometry by making a comparison with the Monte Carlo simulations. Experiments performed at the achieved optimal measurement configuration also show good agreement between the measured and calculated best-fit Mueller matrix spectra. The proposed MCO method based on MOGA is expected to provide a more general and practical means to solve the MCO problem in the state-of-the-art optical scatterometry.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Probing optimal measurement configuration for optical scatterometry by the multi-objective genetic algorithm

Chen

Jiang

et al. 2018

Meas. Sci. Technol.

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“…Nevertheless, optical scatterometry is not restricted by the Abbe diffraction limit that is encountered in image-based metrology techniques. Due to its high-throughput, non-destructive, and ease of in-line integration merits, optical scatterometry is widely used in the measurement of CDs and overlays in semiconductor manufacturing [226][227][228][229][230][231].…”

Section: Optical Scatterometrymentioning

confidence: 99%

An insight on optical metrology in manufacturing

Shimizu

Chen

Kim

et al. 2020

Meas. Sci. Technol.

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Optical metrology is one of the key technologies in today's manufacturing industry. In this article, we provide an insight into optical measurement technologies for precision positioning and quality assessment in today's manufacturing industry. First, some optical measurement technologies for precision positioning are explained, mainly focusing on those with a multi-axis positioning system composed of linear slides, often employed in machine tools or measuring instruments. Some optical measurement technologies for the quality assessment of products are then reviewed, focusing on technologies for form measurement of products with a large metric structure, from a telescope mirror to a nanometric structure such as a semiconductor electrode. Furthermore, we also review the state-of-the-art optical technique that has attracted attention in recent years, optical coherence tomography for the non-destructive inspection of the internal structures of a fabricated component, as well as super-resolution techniques for improving the lateral resolution of optical imaging beyond the diffraction limit of light. This review article provides insights into current and future technologies for optical measurement in the manufacturing industry, which are expected to become even more important to meet the industry's continuing requirements for high-precision and high-efficiency machining.

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“…Among the different techniques, optical scatterometry, sometimes referred to as optical critical dimension (OCD) metrology, has recently achieved great success in the monitoring of CD and overlay [1][2][3][4][5][6]. There are two main procedures in optical scatterometry.…”

Section: Introductionmentioning

confidence: 99%

Improved measurement accuracy in optical scatterometry using correction-based library search

et al. 2013

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Library search is one of the most commonly used methods for solving the inverse problem in optical scatterometry. The final measurement accuracy of the conventional library search method highly depends on the grid interval selected for each parameter in the signature library, and the time cost of the parameter extraction increases dramatically when the grid interval is decreasing. In this paper, we propose a correction-based library search method to improve the measurement accuracy for a pregenerated signature library. We derive a formulation to estimate the error between the expected solution of the inverse problem and the actually searched solution obtained by the conventional library search method. Then we use the estimate of the error as a correction term to correct the actually searched solution to improve the measurement accuracy. Experiments performed on a photoresist grating have demonstrated that the proposed correction-based library search method can achieve much more accurate measurement with negligible computational penalty to the conventional library search method in the parameter extraction. It has also been observed that the correction-based library search method has higher measurement accuracy and less time cost than the interpolation-based library search method. The proposed correction-based library search method is expected to provide a more practical means to solve the inverse problem in state-of-the-art optical scatterometry.

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Overlay measurement using angular scatterometer for the capability of integrated metrology

Cited by 17 publications

References 6 publications

Probing optimal measurement configuration for optical scatterometry by the multi-objective genetic algorithm

Probing optimal measurement configuration for optical scatterometry by the multi-objective genetic algorithm

An insight on optical metrology in manufacturing

Improved measurement accuracy in optical scatterometry using correction-based library search

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