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11/14/2001
1
Polarization Masks: Concept and Initial Assessment
SFR WorkshopNovember 14, 2001
Michael Lam and Andrew NeureutherBerkeley, CA
2001 GOAL: Complete initial simulations and experiments sufficient to design polarization masks and multi-parameter test
structures 9/30/2001
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Motivation: Polarization is a New Lever
• By rotating the polarizations by 90 degrees, the electric fields add as orthogonal vectors rather than co-linear vectors and thereby reduces the undesired intensity by a factor of 2
• Problematic co-linear subtraction at phase edges of phase-shifting masks is converted to vector addition of spatially orthogonal fields, reducing the effect to a 90 degree transition
• Structures can be made to examine quality of polarization.
Polarization orthogonal spillover
Phase-shifted spillover
Polarization adjusted half-tone
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Simulation Approach
2D Tempest near field results
Photomaskpolarization bar test geometries
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Near Fields for Polarization Bars with 3 Gaps
Note that the intensities below the mask are larger for the outboard openings
Contour Plots (Ex) Cutlines (Ex at node z = 12)
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Effect of Gapwidth on Polarization and Transmission
• Cross polarization (Ey) transmission is small, but quickly rises as gapwidth increases.
• Good transmission of desired polarization (Ex) vs. cross polarization (Ey)
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Novel 3D Cross Pattern for Polarization Contacts
Through the use of polarization, the imaging of a normally square contact can be converted to the single exposure of two orthogonal line patterns which can be more easily resolved.
Square Contact
Sequential Exposure of H and V Lines to Form a Smaller Contact
Simultaneous Exposure with Polarization Contact
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3D Cross Pattern, Near Fields in Arm
Very little cross polarization (Ey) is generated from the structure.
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3D Cross Pattern, Near Fields in Center
Initial Results show that more cross polarization is generated near the center and the transmitted field is slightly non uniform.
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2002 and 2003 GoalsConduct and quantitatively interpret polarization masks,
and multi-parameter test structures, by 9/30/2002.
Define apparatus, specify testing procedures, and interpret data for polarization masks, and multi-parameter test structures, by 9/30/2003.
• Studies of the number of gaps and chrome materials• Link the near fields to aerial imaging in SPLAT• Explore novel planar structures and dielectrics