An apparatus for determining information relating to at least one target alignment mark in a semiconductor device substrate. The target alignment mark is initially at least partially obscured by an opaque carbon or metal layer on the substrate. The apparatus includes an energy delivery system configured to emit a laser beam for modifying at least one portion of the opaque layer to cause a phase change and/or chemical change in the at least one portion that increases the transparency of the portion. An optical signal can propagate through the modified portion to determine information relating to the target alignment mark.

Embodiments of the disclosure provides an apparatus for aligning layers of an integrated circuit (IC), the apparatus including: an insulator layer positioned above a semiconductor substrate; a first diffraction grating within a first region of the insulator layer, the first diffraction grating including a first grating material within the first region of the insulator layer; and a second diffraction grating within a second region of the insulator layer, the second grating including a second grating material within the second region of the insulator layer, wherein the second grating material is different from the first grating material, and wherein an optical contrast between the first and second grating materials is greater than an optical contrast between the second grating material and the insulator layer.

Embodiments of the disclosure provides an apparatus for aligning layers of an integrated circuit (IC), the apparatus including: an insulator layer positioned above a semiconductor substrate; a first diffraction grating within a first region of the insulator layer, the first diffraction grating including a first grating material within the first region of the insulator layer; and a second diffraction grating within a second region of the insulator layer, the second grating including a second grating material within the second region of the insulator layer, wherein the second grating material is different from the first grating material, and wherein an optical contrast between the first and second grating materials is greater than an optical contrast between the second grating material and the insulator layer.

A method of measuring overlay uses a plurality of asymmetry measurements from locations (LOI) on a pair of sub-targets (1032, 1034) formed on a substrate (W). For each sub-target, the plurality of asymmetry measurements are fitted to at least one expected relationship (1502, 1504) between asymmetry and overlay, based on a known bias variation deigned into the sub-targets. Continuous bias variation in one example is provided by varying the pitch of top and bottom gratings (P1/P2). Bias variations between the sub-targets of the pair are equal and opposite (P2/P1). Overlay (OV) is calculated based on a relative shift (xs) between the fitted relationships for the two sub-targets. The step of fitting asymmetry measurements to at least one expected relationship includes wholly or partially discounting measurements (1506, 1508, 1510) that deviate from the expected relationship and/or fall outside a particular segment of the fitted relationship.

A method of aligning a plate containing a substrate is disclosed wherein multiple cameras with distinct fields of view are aligned with mark cells that are within the field of view of each of the multiple cameras.

A method for determining one or more optimized values of an operational parameter of a sensor system configured for measuring a property of a substrate is disclosed the method comprising: determining a quality parameter for a plurality of substrates; determining measurement parameters for the plurality of substrates obtained using the sensor system for a plurality of values of the operational parameter; comparing a substrate to substrate variation of the quality parameter and a substrate to substrate variation of a mapping of the measurement parameters; and determining the one or more optimized values of the operational parameter based on the comparing.

The present invention provides an alignment mark, the alignment mark includes at least one dummy mark pattern in a first layer comprises a plurality of dummy mark units arranged along a first direction, and at least one first mark pattern located in a second layer disposed above the first layer, the first mark pattern comprises a plurality of first mark units, each of the first mark units being arranged in a first direction. When viewed in a top view, the first mark pattern completely covers the dummy mark pattern, and the size of each dummy mark unit is smaller than each first mark unit. In addition, each dummy mark unit of the dummy mark pattern has a first width, each first mark unit of the first mark pattern has a second width, and the first width is smaller than half of the second width.

A method of transferring a flexible layer to a substrate makes use of a partial bulge in the flexible layer, which does not make contact with the substrate. The partial bulge advances to the location of an alignment marker on the substrate. When alignment adjustments are needed, they are made with the partial bulge in place so that more reproducible positioning is possible when fully advancing the flexible layer against the substrate.

Techniques are provided for fabricating and utilizing optically opaque non-planar alignment structures in non-die areas (e.g., kerf areas) of a wafer to align photomasks to die areas on the wafer. For example, an insulating layer is formed over non-die and die areas of the wafer. A non-planar alignment feature is formed in the insulating layer in the non-die area. An optically opaque layer stack is formed in the die and non-die areas of the wafer, which conformally covers the non-planar alignment feature to form an optically opaque non-planar alignment structure in the non-die area. A lithographic patterning process is performed to pattern the optically opaque layer stack in the die area, wherein the optically opaque non-planar alignment structure in the non-die area is utilized to align a photomask to the die area. The optically opaque non-planar alignment structure can include any type of non-planar structure having a stepped sidewall surface.

A metrology target having a periodic or quasi-periodic structure, which is characterized by a plurality of parameters. At least one of these parameters varies locally monotonically, wherein the maximum size of this variation over a distance of 5 m is less than 10% of the size of the at least one parameter. In addition, the metrology target has at least one used structure and at least one auxiliary structure, wherein the auxiliary structure transitions progressively into the used structure with regard to the locally monotonically varying parameter. Also disclosed are an associated method and associated device for characterizing structured elements configured as wafers, masks or CGHs.