Integrated circuits and methods for overlap measure are provided. In an embodiment, an integrated circuit includes a plurality of functional cells including at least one gap disposed adjacent to at least one functional cell of the plurality of functional cells and a first overlay test pattern cell disposed within the at least one gap, wherein the first overlay test pattern cell includes a first number of patterns disposed along a first direction at a first pitch. The first pitch is smaller than a smallest wavelength on a full spectrum of humanly visible lights.

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.

A multi-column metrology tool may include two or more measurement columns distributed along a column direction, where the two or more measurement columns simultaneously probe two or more measurement regions on a sample including metrology targets. A measurement column may include an illumination sub-system to direct illumination to the sample, a collection sub-system including a collection lens to collect measurement signals from the sample and direct it to one or more detectors, and a column-positioning sub-system to adjust a position of the collection lens. A measurement region of a measurement column may be defined by a field of view of the collection lens and a range of the positioning system in the lateral plane. The tool may further include a sample-positioning sub-system to scan the sample along a scan path different than the column direction to position metrology targets within the measurement regions of the measurement columns for measurements.

The present invention provides a processing system that includes a first apparatus and a second apparatus, and processes a substrate, wherein the first apparatus includes a first measurement unit configured to detect a first structure and a second structure different from the first structure provided on the substrate, and measure a relative position between the first structure and the second structure, and the second apparatus includes an obtainment unit configured to obtain the relative position measured by the first measurement unit, a second measurement unit configured to detect the second structure and measure a position of the second structure, and a control unit configured to obtain a position of the first structure based on the relative position obtained by the obtainment unit and the position of the second structure measured by the second measurement unit.

A method for aligning a substrate for fabrication of an optical device is disclosed that includes receiving a substrate having a first side and a second side opposite the first side, the first side of the substrate being oriented towards a scanner, the substrate having an alignment mark formed on the first side of the substrate, scanning the alignment mark with the scanner, and fabricating a first pattern for a first optical device on the first side of the substrate. The method includes positioning the substrate such that the second side is oriented toward the scanner, scanning the alignment mark on the first side with the scanner, through the second side, and fabricating a second pattern for a fourth optical device on the second side of the substrate.

Aspects of the present disclosure provide an imaging system. For example, in the imaging system a first light source can generate a first light beam of a first wavelength, a second light source can generate a second light beam of a second wavelength, the second light beam having power sufficient to pass through at least a portion of a thickness of a wafer, an alignment module can coaxially align the second light beam with the first light beam, a coaxial module can focus the coaxially aligned first and second light beams onto a first pattern located on a front side of the wafer and a second pattern located below the first pattern, respectively, and an image capturing module can capture a first image of the first pattern and a second image of the second pattern. The second image can be captured via quantum tunneling imaging or infrared (IR) transmission imaging.

Two pairs of alignment targets (one aligned, one misaligned by a bias distance) are formed on different masks to produce a first pair of conjugated interference patterns. Other pairs of alignment targets are also formed on the masks to produce a second pair of conjugated interference patterns that are inverted the first. Misalignment of the dark and light regions of first interference patterns and the second interference patterns in both pairs of conjugated interference patterns is determined when patterns formed using the masks are overlaid. A magnification factor (of the interference pattern misalignment to the target misalignment) is calculated as a ratio of the difference of misalignment of the relatively dark and relatively light regions in the pairs of interference patterns, over twice the bias distance. The interference pattern misalignment is divided by the magnification factor to produce a self-referenced and self-calibrated target misalignment amount, which is then output.

A sensor device provided in the disclosure includes a sensor substrate, a first transparent layer, a collimator layer, and a lens. The first transparent layer is disposed on the sensor substrate, wherein the first transparent layer defines an alignment structure. The collimator layer is disposed on the first transparent layer. The lens is disposed on the collimator layer.

A method of determining a position of a feature (for example an alignment mark) on an object (for example a silicon wafer) is disclosed. The method comprises determining an offset parameter, determining the second position; and determining a first position from the second position and the offset parameter, the position of the mark being the first position. The offset parameter is a measure of a difference in: a first position that is indicative of the position of the feature; and a second position that is indicative of the position of the feature. The offset parameter may be determined using a first measurement apparatus and the second position may be determined using a second, different measurement apparatus.

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.