The present disclosure relates to an interferometer having an amplified piezoelectric actuator configured to move an optical component. Such an interferometer can be optimized for use in any region of the electromagnetic spectrum and can be used with various applications such as, but not limited to, spectroscopy.

A wafer shape metrology system includes a wafer shape metrology sub-system configured to perform one or more stress-free shape measurements on a first wafer, a second wafer, and a post-bonding pair of the first and second wafers. The wafer shape metrology system includes a controller communicatively coupled to the wafer shape metrology sub-system. The controller is configured to receive stress-free shape measurements from the wafer shape sub-system; predict overlay between one or more features on the first wafer and the second wafer based on the stress-free shape measurements of the first wafer, the second wafer, and the post-bonding pair of the first wafer and the second wafer; and provide a feedback adjustment to one or more process tools based on the predicted overlay. Additionally, feedforward and feedback adjustments may be provided to one or more process tools.

A method for measuring a wafer profile while holding a periphery of the wafer by using a flatness measurement system, including first and second optical systems respectively located on first and second main surfaces of the wafer, the method including: a first step measuring each surface variation on the main surfaces using one of the optical systems; a second step of calculating a periphery-holding deformation amount, caused by holding the wafer periphery, through utilization of the surface variations measured with the optical system; and a third step of calculating an actual wafer Warp value through subtraction of the periphery-holding deformation amount from a Warp value outputted by the flatness measurement system. This provides a method for measuring a wafer profile to enable measurement of actual wafer Warp value by using a flatness measurement system, and to successfully acquire a Warp value with little influence from a difference among systems.

A laser interference device includes: a measurement mirror being movable in an X direction; a reference mirror disposed at a position different from a position of the measurement mirror in a Y direction; a beam splitter having a splitting surface that divides a laser beam into a measurement light and a reference light; a first light guide configured to guide the measurement light incident from the beam splitter and emit the measurement light toward the measurement mirror; and a second light guide configured to guide the reference light incident from the beam splitter and emit the reference light toward the reference mirror, in which a first distribution path formed by the first light guide and a second distribution path formed by the second light guide are mutually equal in a mechanical path length and an optical path length.

A stage device includes a stage capable of moving in a first direction and a second direction orthogonal to each other, a scale arranged in the stage so as to extend in the first direction, an optical assembly arranged so as to face the scale in at least a part of a movable range of the stage and extending in the second direction, and an interferometer configured to transmit measurement light and reference light to the optical assembly, and receive the measurement light and the reference light returning from the optical assembly. The optical assembly is configured to apply the measurement light from the interferometer to the scale, and return the measurement light returning from the scale and the reference light to the interferometer.

Interferometric systems and methods for measuring rotational movement are described. In one implementation, an interferometer for measuring rotational movement includes a housing and a light source within the housing configured to project coherent light toward a non-coded surface of an object. The interferometer further includes at least one optical element configured to modify the projected coherent light in a manner accounting for a rotation of the object. The interferometer also includes at least one sensor within the housing including at least one light detector configured to detect reflections of the modified projected coherent light from the opposing non-coded surface as the object rotates relative to the housing. The interferometer further includes at least one processor configured to receive input from the at least one sensor and determine an amount of rotation of the object around the at least one rotational axis.

We describe apparatus for measurement of thickness and topography of slabs of materials employing probes with filters using polarization maintaining fibers.

The present subject matter at least provides an apparatus for characterization of a slab of a material. The apparatus comprises two or more frequency-domain optical-coherence tomography (FD-OCT) probes configured for irradiating the slab of material, and detecting radiation reflected from the slab of material or transmitted there-through. Further, a centralized actuation-mechanism is connected to the OCT probes for simultaneously actuating elements in each of the OCT probes to cause a synchronized detection of the radiation from the slab of material. A spectral-analysis module is provided for analyzing at least an interference pattern with respect to each of the OCT probes to thereby determine at least one of thickness and topography of the slab of the material. Further, in some embodiments, the slab of material may include a passivation layer. The apparatus may be configured to determine a thickness of the passivation layer.

A laser interference device includes: a measurement mirror being movable in an X direction; a reference mirror disposed at a position different from a position of the measurement mirror in a Y direction; a beam splitter having a splitting surface that divides a laser beam into a measurement light and a reference light; a first light guide configured to guide the measurement light incident from the beam splitter and emit the measurement light toward the measurement mirror; and a second light guide configured to guide the reference light incident from the beam splitter and emit the reference light toward the reference mirror, in which a first distribution path formed by the first light guide and a second distribution path formed by the second light guide are mutually equal in a mechanical path length and an optical path length.

A substrate holder for use with an interferometer comprises a first and second support each comprising a bearing land and a bearing base arranged to form a bearing pocket and a gas inlet fluidly coupled to the bearing pocket. The first support and the second support are positioned relative to one another such that the first bearing pocket is opposed to the second bearing pocket thereby forming a measurement cavity between the first support and the second support. At least one of the first support and the second support comprises reference optics through which one or more interferometric or optical measurements can be taken. Gas supplied to the first bearing pocket and gas supplied to the second bearing pocket form an air bearing in the measurement cavity for supporting a substrate in the measurement cavity without contact between the substrate, the first support, and the second support.