Photomask Recessed Notch Structure for Diffused Reflection Control
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Solution Overview
Problem
In photolithography processes for semiconductor and display device manufacturing, achieving precise and fine construction of photomask layouts to obtain desired circuit patterns with accurate width and pitch is challenging due to issues like diffused reflection and photoresist material spreading.
Innovation Solution
The photomask layout includes a pattern region with notch portions at boundary areas or intersection regions, and a light-shielding portion with recessed portions that overlap the lower stepped pattern, preventing diffused reflection and ensuring uniformity in the photoresist pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional photomask layout is used without notch portions, then the manufacturing process is simpler, but the pattern formation accuracy deteriorates due to diffused reflection and photoresist material spreading
Solution Approach 1:
The light-shielding portion of the photomask is segmented by introducing notch portions at specific locations. These notches divide the continuous light-shielding structure into separate regions, preventing diffused reflection from propagating across the entire structure and improving pattern formation accuracy at the cost of increased photomask complexity
Solution Approach 2:
Notch portions are strategically placed at specific locations where diffused reflection and photoresist spreading occur. This local modification approach addresses the precision problem only where needed, rather than redesigning the entire photomask structure, thus balancing improved accuracy with controlled complexity
2Measurement precision
If the photomask layout includes notch portions to prevent diffused reflection, then pattern formation accuracy improves, but the photomask design and manufacturing becomes more complex
Solution Approach 1:
The notch portions are pre-designed and pre-fabricated into the photomask structure before the actual pattern formation process. This preliminary action ensures that diffused reflection is prevented from the outset, guaranteeing accurate circuit pattern dimensions without requiring additional correction steps during manufacturing
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 accuracy and precision of pattern formation, preventing irregularities and short circuits by controlling the spreading of photoresist material and maintaining uniform width of the target patterns.
Implementation Method 1
a light-shielding portion that at least partially crosses the lower stepped pattern and includes a recessed portion
Implementation Method 2
In the photolithography process, a photomask layout in which a circuit pattern is designed may be prepared, and a photoresist layer may be patterned using the photomask layout
Data Source
AI summary
A photomask layout includes: a substrate region; a lower stepped region at a region of the substrate region; and a pattern region at least partially crossing the lower stepped region and including at least one notch portion at an area overlapping the lower stepped region. A method of forming a pattern is also provided.