Photomask Dotted Line Patterns for Outermost Line Width Control
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Solution Overview
Problem
In semiconductor device microlithography, achieving the desired critical dimension (CD) for outermost line patterns is challenging due to optical proximity effects and limited control over line width and pitch, leading to difficulties in forming wider line widths and potential bridge defects.
Innovation Solution
A method involving a photomask layout with first continuous line patterns, a second continuous line pattern with larger width and space, and a dotted line pattern between them, which induces light scattering to control the line width of outermost patterns on the wafer by varying the size of the dotted patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the line width of the outermost line pattern is intentionally increased to suppress disturbance and improve line resistance, then the line resistance and disturbance suppression are improved, but the optical proximity effect becomes more severe and the pitch control becomes difficult
Solution Approach 1:
The outermost line pattern is segmented into multiple discontinuous line segments instead of a continuous line. This segmentation allows the outermost pattern to have an effective larger width for improved resistance while maintaining the pitch of individual segments for optical control, resolving the contradiction between reliability and manufacturing precision.
2Adaptability or versatility
If the pitch of the dummy line pattern is increased to accommodate the outermost line pattern, then the outermost line pattern can be formed, but the exposure contrast is substantially influenced and line width control becomes limited
Solution Approach 1:
The dummy line pattern is designed with different local properties: it has a larger pitch relative to the outermost line pattern to allow formation, but maintains sufficient exposure contrast through its specific width and spacing characteristics. This local quality differentiation resolves the contradiction between adaptability and manufacturing precision.
3Reliability
If the line width of the outermost line pattern is increased to improve reliability, then disturbance suppression and line resistance are improved, but bridge defects may occur between the outermost line pattern and dummy pattern
Solution Approach 1:
By segmenting the outermost line pattern into discontinuous segments, the effective width is increased for disturbance suppression while the physical separation between segments prevents bridge defects with the dummy pattern, simultaneously achieving both reliability improvement and defect prevention.
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 allows for controlled line width adjustment of outermost patterns, enabling wider line widths and improved resistance, while mitigating optical proximity effects and etch loading issues, thus enhancing the precision and reliability of semiconductor device fabrication.
Implementation Method 1
transferred on a wafer with inducing light scattering by the dotted patterns to form a line pattern
Data Source
AI summary
A method of forming a line pattern array comprises the steps of setting a layout which includes first continuous line patterns arranged to have a first line width and a second continuous line pattern arranged to have a second line width larger than the first line width and positioned outside the first continuous line patterns; transferring the layout on a wafer; and inducing light scattering by changing an outermost pattern of the first continuous line patterns, which is most closely adjacent to the second continuous line patterns, into a plurality of dotted line patterns, wherein the plurality of the dotted patterns are arranged in a line form in order that a line pattern, which is different from the first continuous line patterns in line width, is formed based on a size of the dotted patterns.