Taiwan Semiconductor Manufacturing Comp. Ltd.

Hung-Chih Hsieh

Yen-Liang Chen

Kai-Hsiung Chen

Po-Chung Cheng

Chih-Ming Ke

Kai Wu

Ming-Hsiao Weng

Chun-Liang Lung

An overlay error measurement method includes disposing a lower-layer pattern over a substrate that includes disposing a first pattern having a first plurality of first sub-patterns extending in a first interval along a first direction and being arranged with a first pitch in a second direction crossing the first direction. The method includes disposing a second pattern having a second plurality of second sub-patterns extending in a second interval along the first direction and being arranged with a second pitch, smaller than the first pitch, in the second direction crossing the first direction. The second sub-patterns are disposed interleaved between the first sub-patterns. The method includes disposing an upper-layer pattern including a third pattern having the first pitch and at least partially overlapping with the lower-layer pattern over the lower-layer pattern and determining an overlay error between the lower-layer pattern and the upper-layer pattern.

Frequency-picked methodology for diffraction-based overlay measurement

Frequency-picked methodology for diffraction based overlay measurement

A method of overlay error measurement includes disposing a reference pattern module over a substrate. The substrate includes first and second overlay measurement patterns in first and second locations. The reference pattern module includes first and second reference patterns. The method includes creating a first overlap of the first reference pattern with the first overlay measurement pattern and a second overlap of the second reference pattern with the second overlay measurement pattern. The method further includes determining a first overlay error between the first reference pattern of the reference pattern module and the first overlay measurement pattern of the substrate and determining a second overlay error between the second reference pattern and the second overlay measurement pattern. The method also includes determining a total overlay error between the first and second overlay measurement patterns of the substrate based on the first and second overlay errors.

Method and apparatus for diffraction-based overlay measurement

Methods of fabricating and using an overlay mark are provided. In some embodiments, the overlay mark includes an upper layer and a lower layer disposed below the upper layer. The lower layer includes a first plurality of compound gratings extending in a first direction and disposed in a first region of the overlay mark, each of the first plurality of compound gratings including one first element and at least two second elements disposed on one side of the first element, and a second plurality of compound gratings extending the first direction and disposed in a second region of the overlay mark, each of the second plurality of compound gratings including one third element and at least two fourth elements on one side of the third element. The first plurality of compound gratings is a mirror image of the second plurality of compound gratings.

Overlay marks for reducing effect of bottom layer asymmetry

A method for performing DBO measurements utilizing apertures having a single pole includes using a first aperture plate to measure X-axis diffraction of a composite grating. In some embodiments, the first aperture plate has a first pair of radiation-transmitting regions disposed along a first diametrical axis and on opposite sides of an optical axis that is aligned with a center of the first aperture plate. Thereafter, in some embodiments, a second aperture plate, which is complementary to the first aperture plate, is used to measure Y-axis diffraction of the composite grating. By way of example, the second aperture plate has a second pair of radiation-transmitting regions disposed along a second diametrical axis and on opposite sides of the optical axis. In some cases, the second diametrical axis is substantially perpendicular to the first diametrical axis.

Aperture design and methods thereof

A spectroscopic overlay metrology system and corresponding spectroscopic overlay metrology methods are disclosed herein for improving overly measurement accuracy, optimizing overlay recipes, and/or minimizing (or eliminating) asymmetry-induced overly error from overlay measurements. An exemplary method includes generating a diffraction spectrum by an overlay target from incident radiation having more than one wavelength. The diffraction spectrum includes a plurality of positive ordered diffracted beams and a plurality of negative ordered diffracted beams that are separated by wavelength, such that the diffraction spectrum includes more than one wavelength of a positive order and a negative order. The method further includes collecting intensity information associated with the diffraction spectrum generated by the overlay target from the incident radiation, and generating overlay information from the collected intensity information, where the overlay information includes contributions from asymmetry-induced overlay error. In some implementations, the method includes optimizing an overlay recipe based on the generated overlay information.

Spectroscopic overlay metrology

An overlay metrology tool and diffraction-based overlay measurements are described herein. The tool includes a light source for generating an incident light that illuminates stacked overlay targets formed within material layers of a wafer and a light sensing system for measuring characteristics of a diffracted light beam reflected from the surface of the wafer. During a single illumination of the wafer and without rotating a polarization of the incident light beam, the light sensing system generates three components of the diffracted light beam having one or more polarizations and intensities, according to an overlay recipe associated with the stacked overlay targets.

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Miaoli County, Taiwan

Hung-Chih Hsieh