Phase Shift Mask Variable Thickness for Uneven Substrate Patterning
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Solution Overview
Problem
As LCD apparatus resolution increases, the precision of the patterning process becomes critical, and uneven substrate thickness complicates the patterning process, requiring improved precision and adaptability in mask technology.
Innovation Solution
A phase shift mask with a transparent substrate and a phase shift pattern featuring different thickness areas and opening widths, utilizing materials like chrome oxide nitride and molybdenum silicide oxide nitride to change light phase, allowing for precise patterning without adjusting opening widths based on substrate height differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mask with uniform thickness is used, then the mask structure is simple, but the patterning precision deteriorates when substrate thickness is uneven
Solution Approach 1:
The mask structure transitions from uniform thickness to variable thickness, where different regions of the mask have different thicknesses corresponding to different substrate thicknesses. This local differentiation allows each mask region to compensate for its corresponding substrate's thickness variation, maintaining consistent light focusing and patterning precision across the entire substrate surface.
Solution Approach 2:
The mask thickness parameter is changed from a constant value to a spatially varying value. By adjusting the thickness parameter across different mask regions, the optical path length is compensated for substrate thickness variations, enabling precise patterning despite uneven substrate surfaces.
2Manufacturing precision
If the opening width of the mask is reduced to achieve smaller patterns, then the pattern resolution improves, but the light intensity decreases
Solution Approach 1:
Instead of solely reducing opening width to achieve smaller patterns, the invention changes the mask thickness parameter to control light focusing. By optimizing thickness, the light intensity is maintained while achieving high-resolution patterns through precise optical path control and focusing enhancement.
3Manufacturing precision
If the mask thickness is increased to improve light focusing, then the patterning precision improves, but the manufacturing difficulty increases
Solution Approach 1:
Rather than uniformly increasing mask thickness throughout, the invention applies thickness increases only in specific regions where substrate thickness variations require compensation. This localized approach maintains light focusing precision while reducing overall manufacturing complexity compared to a fully thickened mask structure.
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 phase shift mask provides precise patterns on substrates with varying thicknesses by controlling the thickness of the phase shift pattern, enabling precise patterning even on substrates with height variations, and allowing for patterns smaller than the opening widths of the mask.
Implementation Method 1
a phase shift pattern provided on the transparent substrate. The phase shift pattern includes a first area having a first thickness and a second area having a second thickness which is less than the first thickness
Implementation Method 2
the first and second openings may be configured to focus light in a photoresist layer of a substrate which is an object for patterning disposed under the phase shift mask
Data Source
AI summary
A phase shift device includes a phase shift mask which includes a transparent substrate, and a phase shift pattern which is provided on the transparent substrate, and includes a first area having a first thickness, a second area having a second thickness which is less than the first thickness, a first opening having a first opening width and defined at the first area, and a second opening having a second opening width and defined at the second area.