Phase-Shifting Photomask With Orthogonal Bridging Patterns
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Solution Overview
Problem
Current lithography processes using extreme ultraviolet (EUV) as a light source are expensive and energy-consuming, and struggle to meet the shrinking size requirements of electronic devices, necessitating alternative methods to achieve compact feature sizes and fine line widths.
Innovation Solution
A phase-shifting photomask design with first and second phase-shifting patterns extending in orthogonal directions, where second patterns bridge between neighboring first patterns, enhancing resolution by allowing zero-order and first-order diffracted lights to perform interferometric optical imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV lithography is used to achieve compact feature sizes and fine line widths, then resolution is improved, but manufacturing cost and energy consumption increase significantly
Solution Approach 1:
The patent changes the optical parameters of the existing lithography system by introducing phase-shifting patterns that modify the phase of light passing through different regions of the photomask. This allows the system to achieve higher resolution without changing the light source wavelength or other fundamental parameters, thereby avoiding the high costs associated with EUV lithography while still achieving compact feature sizes
2Manufacturing precision
If EUV lithography is used to achieve compact feature sizes and fine line widths, then resolution is improved, but energy consumption increases
Solution Approach 1:
The patent modifies the phase distribution of light in the optical path by introducing phase-shifting patterns, which enables the existing lower-energy light source to achieve the same resolution效果 as high-energy EUV lithography. This parameter change in the optical system allows energy-efficient manufacturing while maintaining high precision
3Manufacturing precision
If phase-shifting patterns are added to improve resolution, then manufacturing precision is improved, but photomask complexity increases
Solution Approach 1:
The photomask is segmented into distinct functional regions: main feature patterns for primary device structures and bridging feature patterns for enhancing resolution. This segmentation allows each region to perform its specific function independently, making the complex photomask design more manageable and manufacturable while achieving high resolution through the collaborative effect of these segmented regions
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
The improved photomask resolution enables the realization of devices with compact feature sizes and interconnections with fine line widths, overcoming the limitations of EUV-based lithography.
Implementation Method 1
The main feature pattern comprises a material capable of allowing a phase of a light beam passing therethrough shifting about 177° to about 183°
Implementation Method 2
the second phase-shifting patterns bridging between the first phase-shifting patterns included in a main feature pattern, so that the devices with compact feature sizes or the interconnections with fine line widths can be realized
Implementation Method 3
each of the main feature pattern and the bridging feature pattern comprises a material having a light transmittance greater than about 97%
Data Source
AI summary
The present disclosure provides a phase-shifting photomask including a transparent substrate, a main feature pattern disposed on the transparent substrate and including a plurality of first phase-shifting patterns, and a bridging feature pattern disposed on the transparent substrate and including a plurality of second phase-shifting patterns between the two neighboring first phase-shifting patterns. The plurality of first phase-shifting patterns extend in a first direction and are spaced apart from each other in a second direction crossing the first direction. The plurality of second phase-shifting patterns extend in the second direction and are spaced apart from each other in the first direction.