US 11,536,648 B2 · Optical inspection device and method

Abstract

The optical inspection device is used for inspecting a planar object surface for the presence of particles and/or defects. A light source supplies light to the planar object surface of the object at a grazing angle. An image sensor receives light due to scattering from particles and defects on the object surface. The optical axis of the objective is at non-zero angles with the normal to the planar object surface and a direction or directions of specular reflection of the light from the light source by the planar object surface. A detection surface of the image detection device and the optical axis of the objective is in a Scheimpflug configuration. The light source and image sensor are located outside a space extending perpendicularly from the planar object surface, on opposite sides of that space. The image sensor comprises an objective and an image detection device. The device may further comprise a microscope or spectrometer to access the object surface through said space.

Claims17

Dependent claims

A method of inspecting a pellicle mounted above a photolithographic reticle for presence of particles and/or defects, the method comprising:

lighting a top surface of the pellicle, under a grazing angle or range of grazing angles through a polarizer configured to light the top surface of the pellicle with transverse-electric (TE) polarization, from a light source located outside a space extending perpendicularly from the top surface of the pellicle;
imaging the top surface of the pellicle through an objective onto a detection surface of an image detection device,
wherein an optical axis of the objective is at non-zero angles with respect to normal to the top surface of the pellicle and at a direction or directions of specular reflection of the light from the light source by the top surface of the pellicle,
wherein the detection surface and the optical axis of the objective are in a Scheimpflug configuration to focus the top surface of the pellicle onto the detection surface,
wherein the image detection device and the objective are located outside said space, and
wherein said space is located between the objective and the light source.

3 more elements

An optical inspection device for inspecting a pellicle mounted above a photolithographic reticle for presence of particles and/or defects, the optical inspection device comprising:

an object location, with the photolithographic reticle placed on the object location, wherein the pellicle is mounted above the photolithographic reticle for placing an object;
a light source configured to supply light to the top surface of the pellicle, at a grazing angle or range of grazing angles, the light source being located outside a space extending perpendicularly from the top surface of the pellicle;
a polarizer, positioned between the light source and the top surface of the pellicle, that is configured to light the top surface of the pellicle with transverse-electric (TE) polarization;
and
an image sensor comprising an objective and an image detection device,
wherein an optical axis of the objective is at non-zero angles with respect to normal to the top surface of the pellicle and at a direction or directions of specular reflection of the light from the light source by the top surface of the pellicle,
wherein a detection surface of the image detection device and the optical axis of the objective are in a Scheimpflug configuration to focus the top surface of the pellicle onto the detection surface,
wherein the image detection device and the objective are located outside said space, and
wherein said space is located between the objective and the light source.

6 more elements

Dependencies are inferred from the claim text.

Optical inspection device and method

Life of this patent

Optical inspection device and method

Life of this patent

Abstract

Claims17