Using data about the geometry of the wafer, the geometry of the wafer is measured along at least three diameters originating at different points along a circumference of the wafer. A characterization of the geometry of the wafer is determined using the three diameters. A probability of wafer clamping failure for the wafer can be determined based on the characterization.

A system for in-situ measurement of a curvature of a surface of a wafer comprises: a multiwavelength light source module, adapted to emit incident light comprising a plurality of wavelengths; an optical setup configured to combine the incident light into a single beam and to guide the single beam towards a surface of a wafer such that the single beam hits the surface at a single measuring spot on the surface; and a curvature determining unit, configured to determine a curvature of the surface of the wafer from reflected light corresponding to the single beam being reflected on the surface at the single measuring spot.

A height detection apparatus successively changes the brightness of white light from a first level to a second level in accordance with a position of a Z stage and captures an image of interference light while moving a two-beam interference objective lens relative to a paste film in an optical axis direction, detects, as a focus position, a position of the Z stage where the intensity of interference light is highest in a period during which the brightness of white light is set to the first or second level, for each pixel of the captured image, and obtains the height of the paste film based on a detection result.

A thickness measuring apparatus for measuring the thickness of a workpiece held on a chuck table includes the followings: a light source configured to emit white light; an optical branching unit configured to branch, to a second optical path, reflected light applied from the light source to the workpiece held on the chuck table via a first optical path and reflected from the workpiece; a diffraction grating disposed in the second optical path; an image sensor configured to detect an optical intensity signal of light separated into each wavelength by the diffraction grating; and a thickness output unit configured to generate a spectral interference waveform on the basis of the optical intensity signal detected by the image sensor, determine the thickness on the basis of the spectral interference waveform, and output the thickness.

An apparatus and method for die defect detection are disclosed. The apparatus includes: a light source unit (10) for emitting light of at least two wavelengths; a beam splitter (40) for receiving the light emitted by the light source unit (10) and splitting it into a first portion and a second portion, the first portion of the light reflected by a die (60) surface under inspection and thereby forming a detection beam; a reference unit (70) for receiving the second portion of the light and processing it into a reference beam; and a detection unit (90) for receiving the detection beam and the reference beam. The reference beam crosses the detection beam at an angle and thus produces interference fringes on a sensing surface of the detection unit (90), based on which a defect parameter of the die (60) surface under inspection is determined. This apparatus is capable of measuring a die with improved accuracy and efficiency and is suitable for the measurement of large dies.

A shape measuring apparatus of the present invention measures a variation in a thickness of an object to be measured WA based on an A surface reference interference light and an A surface measuring interference light obtained by performing optical heterodyne interference on a first A surface measuring light and a second A surface measuring light and a B surface reference interference light and a B surface measuring interference light obtained by performing the optical heterodyne interference on a first B surface measuring light and a second B surface measuring light. When the optical heterodyne interference is performed, the shape measuring apparatus makes the first A surface measuring light and the second B surface measuring light equal in frequency and makes the first B surface measuring light and the second A surface measuring light equal in frequency.

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 method of using removable opaque coating for accurate optical topography measurements on top surfaces of transparent films includes: depositing a highly reflective coating onto a top surface of a wafer, measuring topography on the highly reflective coating, and removing the highly reflective coating from the wafer. The highly reflective coating includes an organic material. The highly reflective coating comprises a refractive index value between one and two. The highly reflective coating comprises a complex wavelength greater than one at six-hundred and thirty-five nanometers. The highly reflective coating reflects at least twenty percent of incident light. The highly reflective coating when deposited maintains an underlayer pattern topography at a resolution of forty by forty micrometers. The highly reflective coating does not cause destructive stress to the wafer.

A thickness measuring apparatus measures the thickness of a wafer. The apparatus includes a light source for emitting light having a transmission wavelength region to the wafer, a focusing unit for applying the light emitted from the light source to the wafer, a first optical path for optically connecting the light source to the focusing unit, an optical branching section provided on the first optical path for branching the light reflected on the wafer and then guiding the reflected light to a second optical path, a diffraction grating provided on the second optical path for diffracting the reflected light to obtain diffracted light of different wavelengths, an image sensor for detecting the intensity of the diffracted light according to the different wavelengths and producing a spectral interference waveform, and a control unit having a thickness computing section for computing the spectral interference waveform to output thickness information.

Wafer geometry measurement tools and methods for providing improved wafer geometry measurements are disclosed. Wafer front side, backside and flatness measurements are taken into consideration for semiconductor process control. The measurement tools and methods in accordance with embodiments of the present disclosure are suitable for handling any types of wafers, including patterned wafers, without the shortcomings of conventional metrology systems.