Lithography Polarization Control for Multi-Axis Pattern Resolution
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Solution Overview
Problem
Conventional lithography methods fail to achieve satisfactory resolution and compatibility with current equipment for semiconductor devices with complex patterns having axes in different directions, as they can only divert light beams to a single polarization direction.
Innovation Solution
A lithography apparatus with a polarization controlling system that diverts the polarization direction of incident light beams to be parallel to the longest axis of each pattern on the photomask, utilizing multiple polarization controlling units, such as liquid crystal layers or wave plates with MEMS, to accommodate patterns with axes in different orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single polarization direction illumination is used, then equipment simplicity is maintained, but resolution for complex patterns with multiple axis orientations cannot be improved
Solution Approach 1:
The illumination system is segmented into multiple independent polarization controlling units, each responsible for a specific polarization direction. This allows the system to handle complex patterns with multiple axis orientations by dividing the illumination task into separate polarization channels, thereby improving resolution without requiring a complete system redesign
Solution Approach 2:
The polarization controlling system is designed to be universal by accommodating multiple polarization directions simultaneously. The system can adapt to different pattern orientations on the photomask by adjusting the polarization state of incident light, making it applicable to various lithography scenarios while maintaining improved resolution
2Manufacturing precision
If off-axis illumination or immersion lithography is used, then resolution may be improved, but compatibility with current equipment and depth of focus are compromised
Solution Approach 1:
Instead of changing fundamental illumination parameters like numerical aperture or immersion medium that would affect depth of focus and equipment compatibility, the invention changes the polarization state parameter of the incident light. This parameter change improves resolution for complex patterns while maintaining compatibility with existing lithography equipment and preserving depth of focus characteristics
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the resolution of the lithography process by allowing light to be directed optimally for patterns with varying orientations, improving the transfer of circuit patterns onto substrates without compromising depth of focus.
Implementation Method 1
a polarization controlling system positioned between the light source and the photomask, wherein the polarization controlling system comprises a first polarization controlling unit and a second polarization controlling unit, wherein the first polarization controlling unit diverts a polarization direction of the first light beam to a direction which is parallel to the first axis, and the second polarization controlling unit diverts a polarization direction of the second light beam to a direction which is parallel to the second axis
Data Source
AI summary
A lithography apparatus includes: a light source comprising a first light beam and a second light beam, a photomask, a polarization controlling system positioned between the light source and the photomask, a wafer state for holding a wafer, and a lens positioned between the photomask and the wafer stage. The polarization controlling system diverts the first light beam into a first polarization direction and diverts the second light beam into a second polarization direction, wherein the first polarization direction and the second polarization direction are different from each other.