Browse Prior Art Database

Method for semiconductor metrology through MPQS

IP.com Disclosure Number: IPCOM000012782D
Publication Date: 2003-May-28
Document File: 3 page(s) / 113K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for semiconductor metrology through multiphoton quantum scatterometry (MPQS). Benefits include improved performance.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 54% of the total text.

Method for semiconductor metrology through MPQS

Disclosed is a method for semiconductor metrology through multiphoton quantum scatterometry (MPQS). Benefits include improved performance.

Background

      Semiconductor metrology requires higher critical dimension (CD) metrology resolution (below 20 nm) capability without shorter wavelength light sources. Conventionally, only classical scatterometry exists. Solutions utilize CD scanning electron microscopes, scatterometry, and microscopes.

General description

      The disclosed method is quantum scatterometry to increase the CD measurement capability for nanofabrication. Light is used to create multiple entangled photon states and to detect the subsequent response with a detector, which is only sensitive to the multiphoton transition.

Advantages

              The disclosed method provides advantages, including:

•             Improved performance due to achieving higher CD metrology resolution (below 20 nm) capability without shorter wavelength light sources by employing quantum effects

Detailed description

              The disclosed method includes quantum scattering/imaging and the construction of a quantum scatterometry system.

Quantum scattering/imaging

              In classical imaging, individual photons are uncorrelated and resolution is limited through diffraction of the exit pupil of the optical system. This effect leads to the half-pitch feature size (p/2) resolution limit for an optical system in air with numerical aperture (NA) and wavelength (λ), as described by an equation (see Figure 1).

              Two plane waves interfere (in the image plane) at an incident angle q leading to a half-pitch resolution (the Raleigh limit) of λ/(4NA). Note that the 0th diffraction order is omitted as it only adds a constant background signal (see Figure 2).

              Quantum imaging is fundamentally different from conventional light imaging as quantum imaging makes use of entangled or correlated photon states. Imaging with entangled photons has no classical analogue and leads to new and counterintuitive results. For example, entangled photons-pairs are created inside a microscope from parametrically down-converted laser light. By using a light detector that is only sensitive to a two-photon absorption process, feature sizes can be theoretically resolved at half the Raleigh resolution limit.

              For example, in a two-photon process, N equals 2 (see Figure 3). Higher order multiphoton processes are possible. An N...