H-Shaped Photomask Layout with Zebra-Crossing Central Zone
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional photomask layouts for semiconductor manufacturing suffer from optical proximity effects, such as line end pullback and tapered bottlenecks, especially in H-shaped patterns, which are not adequately addressed by existing optical proximity correction (OPC) methods, leading to defects and increased costs.
Innovation Solution
A photomask layout featuring an H-shaped pattern with a central zebra-crossing zone having a dense line-space pattern beyond the resolution limit of exposure tools, ensuring inadequate light exposure to prevent line-space image formation on the photoresist layer, thereby controlling line end pullback and resolving tapered bottlenecks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography is used to transfer H-shaped patterns, then the manufacturing process is simple, but optical proximity effects cause line end pullback and tapered bottlenecks leading to defects
Solution Approach 1:
The central zone of the H-shaped pattern is segmented into multiple parallel line patterns with specific pitch relationships. This segmentation creates controlled optical interference that compensates for the pullback effect at line ends, improving pattern transfer accuracy without requiring complex OPC procedures
Solution Approach 2:
Different zones of the photomask pattern are given different properties: the stem regions use standard line patterns while the central zone uses a specific dense line-space pattern with pitch between 0.5-1.5 times the exposure tool resolution limit. This local differentiation addresses the optical proximity effect specifically where it occurs most severely
2Manufacturing precision
If OPC methods are employed to correct optical proximity effects, then pattern transfer accuracy improves, but manufacturing time and cost increase
Solution Approach 1:
The photomask is designed with pre-calculated geometric features (central zone with specific line patterns) that inherently compensate for optical proximity effects during exposure. This preliminary design approach eliminates the need for time-consuming post-exposure OPC calculations and iterations, maintaining high pattern transfer accuracy while improving manufacturing efficiency
3Manufacturing precision
If the pitch of line-space pattern is reduced to control optical proximity effects, then pattern fidelity improves, but the exposure tool resolution limit is exceeded causing inadequate light exposure
Solution Approach 1:
The pitch of the line-space pattern in the central zone is precisely controlled within a specific range (0.5-1.5 times the exposure tool resolution limit). This parameter optimization allows the pattern to benefit from optical proximity correction while still receiving adequate exposure energy, achieving line end position accuracy without sacrificing illumination intensity
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 proposed photomask layout effectively reduces line end pullback to less than 10 nm and addresses tapered bottlenecks, enhancing the precision and efficiency of semiconductor pattern transfer without the need for OPC, thus reducing costs and improving manufacturing accuracy.
Implementation Method 1
a dense line-space pattern is disposed in the central zone. The pitch of the dense line-space pattern is beyond resolution limit of an exposure tool such that light passing the central zone has an exposure energy that is not adequate to form corresponding line-space image on a photoresist layer
Data Source
AI summary
A photomask layout pattern including an H-shaped pattern having a first opaque line pattern in parallel with a second opaque line pattern and a central zone connecting the first and second line patterns. A zebra-crossing-like dense line and space pattern is disposed in the central zone. The pitch of the zebra-crossing-like dense line and space pattern is beyond the resolution limit of an exposure tool such that light passing the central zone has an exposure energy that is not adequate to form corresponding line/space image on a photoresist.