Semiconductor Dummy Patterns Stabilize Light Intensity
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Solution Overview
Problem
The existing photolithography processes in semiconductor manufacturing face challenges with pattern formation due to light intensity fluctuations caused by diffraction effects, leading to reduced pattern sizes and increased yield loss, especially during defocusing conditions.
Innovation Solution
The introduction of dummy patterns with specific spacings and arrangements, such as polygonal patterns and resolution dummy patterns, stabilizes light intensity distribution, preventing excessive fluctuations and ensuring uniform pattern density, even in areas with varying pattern densities and during defocusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography exposure is performed without dummy patterns, then the manufacturing process is simple, but light intensity fluctuations cause pattern shrinkage and yield loss
Solution Approach 1:
Dummy patterns are added to the photomask design in advance, before the actual exposure process. These dummy patterns are strategically positioned around the target patterns to pre-compensate for light intensity fluctuations and diffraction effects that would otherwise cause pattern shrinkage during exposure.
Solution Approach 2:
Dummy patterns act as intermediary elements between the light source and the target patterns. They modify the light distribution by creating controlled diffraction and interference effects that compensate for the harmful optical proximity effects, thereby stabilizing the light intensity at the target pattern locations.
2Manufacturing precision
If dummy patterns are added to stabilize light intensity, then pattern size accuracy improves, but photomask design and manufacturing complexity increases
Solution Approach 1:
Dummy patterns are selectively placed only in specific regions where optical intensity fluctuations and diffraction effects are most problematic. The density, size, and spacing of dummy patterns are locally optimized based on the specific geometric characteristics and spacing of the target patterns in each region, rather than uniformly applying dummy patterns across the entire photomask.
Solution Approach 2:
The parameters of dummy patterns (such as their size, spacing, density, and geometric shape) are carefully optimized to achieve the desired light intensity stabilization. By adjusting these parameters, the dummy patterns can be tuned to compensate for specific diffraction and optical proximity effects without excessively increasing photomask complexity.
3Productivity
If exposure is performed with standard light intensity distribution, then the exposure process is fast, but defocusing causes severe pattern shrinkage and yield loss
Solution Approach 1:
Dummy patterns are designed to create a cushioning effect against light intensity fluctuations and defocusing errors. By strategically positioning dummy patterns, they generate compensating optical effects that protect the target patterns from shrinkage even when defocusing occurs during the exposure process, thereby maintaining pattern formation reliability without slowing down production.
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 prevents pattern shrinkage and peeling, thereby enhancing the accuracy and yield of semiconductor device manufacturing by maintaining consistent pattern sizes and reducing the risk of yield reduction.
Implementation Method 1
light intensity fluctuations caused by diffraction effects
Data Source
AI summary
A semiconductor device includes a first pattern and a plurality of second patterns arranged at equal intervals. When the distance of the space between the first pattern and the second pattern closet to the first pattern is larger than a first distance, a plurality of dummy patterns are arranged in the space with shapes and intervals similar to those of the second patterns. When the distance of the space is equal to or less than the first distance and larger than a second distance, the dummy pattern is spaced from the second pattern closest to the first pattern, and extends toward the first pattern to be brought into contact with the first pattern. When the distance of the space is equal to or less than the second distance, the dummy pattern is spaced from the second pattern closest to the first pattern, and is connected to the first pattern.