Optical metrology tool, LX530, is designed for high throughput and dense sampling metrology in semiconductor manufacture. It can inspect the dose and focus variation in the process control based on the critical dimension (CD) and line edge roughness (LER) measurement. The working principle is shown with a finite-difference-time-domain (FDTD) CD simulation. Two optical post lithography wafers, including one focus-exposure-matrix (FEM) wafer and one nominal wafer, are inspected for CD, dose and focus analysis. It is demonstrated that dose and focus can be measured independently. A data output method based on global CD uniformity (CDU), inter CDU and intra CDU is proposed to avoid the data volume issue in dense sampling whole wafer inspection.
A new direct Phase-shift/Transmittance measurement tool "MPM193EX" has been developed to respond to the
growing demand for higher precision measurements of finer patterns in ArF Lithography. Specifications of MPM193EX
are listed below along with corresponding specifications of the conventional tool MPM193.
1) Phase-shift [3 Sigma]: 0.5 deg. (MPM193) => 0.2 deg. (MPM193EX)
2) Transmittance [3 Sigma]: 0.20 % (MPM193) => 0.04 % (MPM193EX)
3) Minimum measurement pattern width: 7.5 μm (MPM193) => 1.0 μm (MPM193EX)
Furthermore, new design optics using an ArF Laser and an objective lens with long working distance allows
measurements of masks with pellicles.
The new method for improving the measurement repeatability is based on elimination of influence from instantaneous
fluctuation in interferometer fringes by scanning two adjacent areas simultaneously. Also, MPM193EX is equipped with
high-resolution and stable optics. The newly employed auto-focus system in MPM193EX accurately adjusts, by a new
image processing method using high-resolution optics, the focus height that is one of the most important factors for
measurements in a micro pattern.