Method and apparatus for angular-resolved spectroscopic lithography characterization
AssigneeASML Netherlands B.V.
InventorsArie Jeffrey Den Boef, Everhardus Cornelis Mos, Maurits Van Der Schaar
Life of this patent
Estimating the term…
Abstract
Both the 1st and 0th diffraction orders are detected in a scatterometer. The 1st diffraction orders are used to detect the overlay error. The 0th diffraction order is then used to flag if this is a false overlay error calculation of magnitude greater than the bias but smaller than the pitch of the grating.
Claims13
A method of measuring a property of a substrate, comprising:
- projecting radiation onto a substrate using a radiation projector and;
- detecting the 0th order and ±nth orders of the reflected radiation, wherein n>1 and the reflected radiation is indicative of the property to be measured.
A scatterometer configured to measure a property of a substrate, the scatterometer comprising:
- a radiation projector configured to project radiation onto a plurality of superimposed patterns on the substrate;
- a detector configured to detect the 0th and ±nth diffraction orders of the radiation beam reflected from a surface of the substrate, wherein n>1;
- and
- a data handling unit configured to calculate overlay error between the plurality of superimposed patterns based on the 0th and ±nth diffraction orders.
A lithographic apparatus comprising an inspection apparatus, the inspection apparatus comprising
- a radiation projector configured to project radiation onto a plurality of superimposed patterns on a substrate;
- a detector configured to detect the 0th and ±nth diffraction orders of the radiation beam reflected from a surface of the substrate, wherein n>1;
- and
- a data handling unit configured to calculate overlay error between the plurality of superimposed patterns based on the 0th and ±nth diffraction orders.
A lithographic apparatus, comprising:
- an illumination system configured to condition a beam of radiation;
- a support configured to support a patterning device, the patterning device being configured to impart the beam of radiation with a pattern in its cross section;
- a substrate table configured to hold a substrate;
- a projection system configured to project the patterned beam of radiation onto a target portion of the substrate;
- and
- an inspection apparatus, the inspection apparatus comprising
- a radiation projector configured to project radiation onto a plurality of superimposed patterns on the substrate;
- a detector configured to detect the 0th and ±nth diffraction orders of the radiation beam reflected from a surface of the substrate, wherein n>1;
- and
- a data handling unit configured to calculate overlay error between the plurality of superimposed patterns based on the 0th and ±nth diffraction orders.
Dependencies are inferred from the claim text.