Phase-Shift Mask Third Region Pattern Resolution
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Solution Overview
Problem
Conventional phase shift masks experience phase conflict issues due to reduced feature sizes, leading to interconnects between line patterns and annular defects, compromising pattern resolution and quality.
Innovation Solution
A phase-shift mask design that includes a third phase-shift region at the terminal ends of the second phase-shift region to cancel interference effects, ensuring independent line patterns by adjusting the phase differences between the regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pitch between line patterns is reduced to achieve higher resolution, then the feature size decreases and resolution improves, but phase conflict occurs leading to interconnects and annular defects
Solution Approach 1:
The mask pattern is segmented into multiple phase-shift regions (first, second, and third phase-shift regions) with different phase characteristics. This segmentation allows independent control of phase relationships in different areas, preventing unwanted interference between adjacent line patterns while maintaining high resolution.
Solution Approach 2:
Different regions of the mask are assigned different phase properties - the first and second phase-shift regions have one phase relationship, while the third phase-shift region introduces a different phase relationship at critical boundaries. This local differentiation resolves phase conflict at specific locations without affecting overall pattern resolution.
2Manufacturing precision
If conventional phase shift masks are used with reduced pitch, then resolution enhancement is achieved, but interconnects form between adjacent line patterns
Solution Approach 1:
The third phase-shift region is designed to preemptively counteract the phase conflict that would otherwise cause interconnects. By introducing a phase relationship that opposes the harmful interference before it occurs, the design prevents interconnect formation at the boundaries between adjacent line patterns.
Solution Approach 2:
The phase conflict that initially causes harmful interconnects is converted into a beneficial effect by strategically placing the third phase-shift region. The same phase difference that could cause interference is now used to create destructive interference precisely where needed to prevent interconnects, transforming a harmful phenomenon into a protective mechanism.
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
Prevents phase conflict and interconnects, maintaining high resolution and quality of lithographic patterns even with reduced pitch, effectively addressing the limitations of prior art phase shift masks.
Implementation Method 1
When the light passes through the phase shifter of the phase shift masks, the phase of the electric field of the light is shifted exactly 180°
Implementation Method 2
the phase difference between the incident light and the shifted light is exactly half a wavelength and destructive interference therefore occurs on the wafer
Implementation Method 3
The interference effect of the diffraction is resolved by the destructive interference
Data Source
AI summary
A phase-shift mask for forming a pattern includes a glass substrate and a pattern, a first phase-shift region, a second phase-shift region and a third phase-shift region on the glass substrate. The first phase-shift region and the second phase-shift region are alternately arranged and the third phase-shift regions are formed at the terminal ends of the first phase-shift region.