Topic
Mask inspection
About: Mask inspection is a research topic. Over the lifetime, 1072 publications have been published within this topic receiving 8696 citations.
Papers published on a yearly basis
Papers
More filters
••
06 Oct 2011
TL;DR: In this paper, the Holon E-beam inspection (EBI) method was used for 16 and 11 nm patterned mask inspections, and the performance of the EBI method was evaluated on 22 nm test masks.
Abstract: EUV lithography is expected to begin production in 2014. Production of successful EUV photomasks requires patterned
mask inspection (PMI). The ultimate PMI tool is expected to utilize actinic (EUV) illumination. Development of such a
tool is expected to require three years after funding. Current test EUV masks, such as 22 nm, can be inspected using 193
nm wavelength deep UV (DUV) inspection tools similar to those currently being used for DUV masks. The DUV
inspection tools may be extended for the 16 nm node. However EUV production is expected to start with 11 nm node
masks which cannot be inspected with proposed DUV inspection tools. Therefore E-beam inspection (EBI) is discussed
as the interim PMI method.
EBI has the advantage of high resolution and the disadvantages of low inspection speed and relative insensitivity to ML
defects (in the multi-layer material). EBI inspection speed is limited by the pixel size, pixel capture rate and the number
of electron columns. The pixel rate is limited by the detector time-resolution, the beam current, and the detection
efficiency.
Technical improvements in beam focus, secondary electron detection, and defect detection and analysis provide good
performance for 22 nm node masks. We discuss the advances and show that performance can be extrapolated for 16 and
11 nm node patterned mask inspections.
We present sensitivity and false-defect frequency results of using the Holon EBI tool on 22 nm test masks and a roadmap
for extending its operation for use on 16 and 11 nm node masks for inspections requiring 2-5 hours per mask.
1 citations
•
20 Apr 2015TL;DR: In this paper, a wavefront correction element for use in an optical system, in particular in a microlithographic projection exposure apparatus, or a mask inspection tool, with a carrier film (110, 210, 410) is described.
Abstract: The invention relates to a wavefront correction element for use in an optical system, in particular in an optical system of a microlithographic projection exposure apparatus, or a mask inspection tool, with a carrier film (110, 210, 410) which is incident in the operation of the optical system to the carrier foil, an operating wavelength of the optical Systems having electromagnetic radiation at least partially transmitted, wherein the base film (110, 210, 410) is designed such that the real part of the complex refractive index over a useful range of the surface of the carrier film (110, 210, 410) varied.
1 citations
••
TL;DR: In this article, the authors devised a new ellipsometric technique to investigate the inner surface of mask without removing pellicle, which can be used to measure any film or partial film formed on non-patterned spot in early stage of growth.
Abstract: Crystal growth and haze formation on photomasks become serious problems in UV lithography. As the
wavelength becomes shorter, photons carry more energy, so the chances of having a photochemical reaction become
much higher. Pellicle, adhesive, residue from cleaning or resist strip process, and any contaminant in air can react with
UV to form unwanted crystals and a haze layer on reticles. These will reduce the light transmission during exposure
process. Thus, frequent mask inspection and periodic mask cleaning are needed to overcome these problems. However,
these will in turn increase manufacturing cost and reduce mask life. Thus, a proper mask inspection tool is required to
provide early warning of haze formation. In this work, we devised a new ellipsometric technique to investigate the inner
surface of mask without removing pellicle. Ellipsometry is known to have mono-layer sensitivity and it can be used to
measure any film or partial film formed on non-patterned spot in early stage of growth. However, when a pellicle covers
the surface of mask, the ellipsometric data reflected from surface are extremely distorted due to the non-normal
transmission through the pellicle. Thus, data analysis becomes extremely difficult without knowing the optical
properties of pellicles. In order to solve this problem we developed compensation technique in which two blank pellicles
are situated in the optical path in a way to compensate the polarization changes caused by the pellicle on mask. With this
method, the conventional ellipsometry spectra of {Δ, Ψ} are deduced.
1 citations
01 Jan 2004
TL;DR: In this article, a hybrid concept combining diffractive and refractive optical elements was proposed for a high NA, large working distance, microscope objective, which was demonstrated by investigating different mask features.
Abstract: The capability of a high NA, large working distance, microscope objective was demonstrated by investigating different mask features. The microscope objective is based on a hybrid concept combining diffractive and refractive optical elements. Resolution down to 125 nm lines and spaces (L/S) is demonstrated by investigating periodic chrome on glass structures. A significant additional improvement of the resolution is achieved by introducing a solid immersion lens (SIL).
1 citations