Particle detection for patterned wafers of 100nm design rule by evanescent light illumination: analysis of evanescent light scattering using Finite-Difference Time-Domain (FDTD) method

2005 ◽  
Author(s):  
Toshie Yoshioka ◽  
Takashi Miyoshi ◽  
Yasuhiro Takaya
Keyword(s):  
Light Scattering ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Design Rule ◽  
Light Illumination ◽  
Particle Detection ◽  
Patterned Wafers ◽  
Evanescent Light ◽  
Difference Time

Particle Detection for 100-nm Patterned Wafers by Evanescent Light Illumination – Analysis of Evanescent Light Scattering Using Finite-Difference Time-Domain Method –

2006 ◽  
Vol 18 (6) ◽  
pp. 705-713
Author(s):  
Toshie Yoshioka ◽  
◽  
Takashi Miyoshi ◽  
Yasuhiro Takaya
Keyword(s):  
Light Scattering ◽  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Wafer Surface ◽  
Light Illumination ◽  
Particle Detection ◽  
Wafer Inspection ◽  
Evanescent Light ◽  
Difference Time

Patterned wafer inspection technique is essential to high productivity and reliability in high-yield semiconductor manufacturing. Since circuit features are below 100nm, conventional imaging and light scattering methods cannot be applied to patterned wafer inspection technique due to the diffraction limit and the low S/N ratio. We propose a new particle detection method using annular evanescent light illumination. In this method, a converging annular beam used as a light source is incident to a micro-hemispherical lens. When the converging angle is greater than the critical angle, annular evanescent light is generated on the bottom surface of the hemispherical lens. Evanescent light is localized near the bottom of the hemispherical lens and decays exponentially away from it, so the evanescent light selectively illuminates a particle on the patterned wafer surface because it cannot illuminate the patterned wafer surface. The proposed method evaluates a particle on a patterned wafer surface by detecting scattered evanescent light pattern from the particle. To analyze the fundamental properties of the proposed method, the computer simulation was performed using the finite-difference time-domain (FDTD) method. It is found that the proposed method is effective for detecting 100nm sized particle on a patterned wafer consisting of 100nm lines and spaces, when the evanescent light illumination is done using P-polarized light and line orientation parallel to the incident plane. Finally, the experimental results suggest that 220nm sized particle can be detected on a patterned wafer consisting of about 200nm lines and spaces.

scholarly journals From Time-Collocated to Leapfrog Fundamental Schemes for ADI and CDI FDTD Methods

Axioms ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Eng Leong Tan
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Unconditionally Stable ◽  
Alternating Direction Implicit ◽  
One Dimensional ◽  
Alternating Direction ◽  
Fdtd Methods ◽  
Difference Time

The leapfrog schemes have been developed for unconditionally stable alternating-direction implicit (ADI) finite-difference time-domain (FDTD) method, and recently the complying-divergence implicit (CDI) FDTD method. In this paper, the formulations from time-collocated to leapfrog fundamental schemes are presented for ADI and CDI FDTD methods. For the ADI FDTD method, the time-collocated fundamental schemes are implemented using implicit E-E and E-H update procedures, which comprise simple and concise right-hand sides (RHS) in their update equations. From the fundamental implicit E-H scheme, the leapfrog ADI FDTD method is formulated in conventional form, whose RHS are simplified into the leapfrog fundamental scheme with reduced operations and improved efficiency. For the CDI FDTD method, the time-collocated fundamental scheme is presented based on locally one-dimensional (LOD) FDTD method with complying divergence. The formulations from time-collocated to leapfrog schemes are provided, which result in the leapfrog fundamental scheme for CDI FDTD method. Based on their fundamental forms, further insights are given into the relations of leapfrog fundamental schemes for ADI and CDI FDTD methods. The time-collocated fundamental schemes require considerably fewer operations than all conventional ADI, LOD and leapfrog ADI FDTD methods, while the leapfrog fundamental schemes for ADI and CDI FDTD methods constitute the most efficient implicit FDTD schemes to date.

scholarly journals Butterfly-Inspired 2D Periodic Tapered-Staggered Subwavelength Gratings Designed Based on Finite Difference Time Domain Method

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Houxiao Wang ◽  
Wei Zhou ◽  
Er Ping Li ◽  
Rakesh Ganpat Mote
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Fdtd Method ◽  
Subwavelength Structures ◽  
Surface Reflection ◽  
Subwavelength Gratings ◽  
Difference Time

The butterfly-inspired 2D periodic tapered-staggered subwavelength gratings were developed mainly using finite difference time domain (FDTD) method, assisted by using focused ion beam (FIB) nanoscale machining or fabrication. The periodic subwavelength structures along the ridges of the designed gratings may change the electric field intensity distribution and weaken the surface reflection. The performance of the designed SiO2gratings is similar to that of the corresponding Si gratings (the predicted reflectance can be less than around 5% for the bandwidth ranging from 0.15 μm to 1 μm). Further, the antireflection performance of the designedx-unspaced gratings is better than that of the correspondingx-spaced gratings. Based on the FDTD designs and simulated results, the butterfly-inspired grating structure was fabricated on the silicon wafer using FIB milling, reporting the possibility to fabricate these FDTD-designed subwavelength grating structures.

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