Photomask Non-Printing Features Bridge Density Gaps
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Solution Overview
Problem
Current photomask designs in the semiconductor industry are inadequate in addressing distortions caused by diffraction during lithography, leading to suboptimal pattern formation on semiconductor wafers, and do not effectively manage debris particles, which affects the longevity and performance of photomasks.
Innovation Solution
The introduction of non-printing feature insertion (NPI) regions in the photomask design, where non-printing features are inserted in isolated areas to bridge density gaps between dense and isolated regions, and to attract and trap debris particles, thereby improving pattern density and extending photomask lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photomask designs use conventional patterns without non-printing features, then the manufacturing process is simpler, but pattern formation precision deteriorates due to density gaps between dense and isolated regions
Solution Approach 1:
Non-printing features are introduced as intermediary elements between dense and isolated printing features. These intermediary features bridge the density gap by providing intermediate density values, enabling smoother density transitions and reducing etching behavior differences without directly affecting the printed pattern on the wafer.
Solution Approach 2:
The photomask is divided into different regions with locally optimized characteristics. Non-printing features are selectively inserted in specific isolated regions where density gaps exist, while leaving other regions unchanged. This local modification approach improves pattern formation precision only where needed without unnecessarily complicating the entire photomask structure.
2Duration of action of stationary object
If photomask designs include non-printing features, then debris particle management improves and photomask lifespan extends, but the photomask structure becomes more complex
Solution Approach 1:
Non-printing features convert the harmful effect of debris accumulation into a beneficial trapping mechanism. By providing dedicated non-critical regions with non-printing features, debris particles are attracted to and trapped in these areas instead of accumulating on critical printing features, thereby extending photomask operational lifespan while isolating the complexity to non-essential structures.
3Stability of the object's composition
If non-printing features are inserted to bridge density gaps, then etching behavior uniformity improves, but the photomask design complexity increases
Solution Approach 1:
The density parameter is modified by inserting non-printing features in isolated regions. By changing the local density parameter in specific areas without affecting printing features, the etching behavior uniformity across the photomask is improved. The non-printing features provide intermediate density values that create a more uniform density distribution, leading to consistent etching rates across different 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
This approach enhances pattern formation precision, reduces etching behavior differences between dense and isolated regions, and effectively prolongs the photomask's operational time by preventing debris accumulation on critical features.
Implementation Method 1
non-printing features are inserted in isolated areas to bridge density gaps between dense and isolated regions, and to attract and trap debris particles
Implementation Method 2
optical proximity correction (OPC) and inserts various OPC patterns to compensate for distortions caused by diffraction of radiation that occurs during the use of a lithography tool
Data Source
AI summary
Photomasks and methods of fabricating the photomasks are provided herein. In some examples, a layout for forming an integrated circuit device is received. The layout includes a set of printing features. A region of the layout is identified. The region is at a distance from the set of printing features such that an exposure region associated with a feature in the region does not affect a set of exposure regions associated with the set of printing features. A plurality of non-printing features is inserted into the region. A photomask is fabricated based on the layout.