Tight-Pitched Pattern Formation via Dual Illumination Exposure
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in forming tight-pitched patterns with desired critical dimensions and improved resolution due to limitations in image quality and resolution when using dipole or cross-quadrapole illumination light sources.
Innovation Solution
A method involving two exposure processes using a single photomask, where the first exposure process employs a high-resolution light source to resolve the width of the pattern and the second exposure process uses a lower-resolution light source to achieve the desired length, with the dosage ratio between the processes adjusted to optimize the critical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dipole illumination light source is used, then the resolution of width direction is improved, but the critical dimension of length cannot meet the predetermined value
Solution Approach 1:
The exposure process is segmented into two separate exposure processes with different illumination conditions. The first exposure uses dipole illumination optimized for width resolution, while the second exposure uses cross-quadrapole illumination optimized for length critical dimension, allowing each exposure to independently optimize for its specific dimensional requirement without compromising the other
Solution Approach 2:
The illumination light source is dynamically changed between two different configurations (dipole and cross-quadrapole) for the two separate exposure processes. This dynamic adjustment of illumination conditions allows the system to adapt to different resolution requirements for different dimensions of the same pattern
2Manufacturing precision
If cross-quadrapole illumination light source is used, then the critical dimension of length reaches the predetermined value, but the resolution of width is reduced
Solution Approach 1:
The exposure process is segmented into two separate exposure processes with different illumination conditions. The first exposure uses dipole illumination optimized for width resolution, while the second exposure uses cross-quadrapole illumination optimized for length critical dimension, allowing each exposure to independently optimize for its specific dimensional requirement without compromising the other
Solution Approach 2:
The illumination light source is dynamically changed between two different configurations (dipole and cross-quadrapole) for the two separate exposure processes. This dynamic adjustment of illumination conditions allows the system to adapt to different resolution requirements for different dimensions of the same pattern
3Manufacturing precision
If photomask pattern length is reduced, then the simulated CD of length decreases, but both resolutions of length and width become worse
Solution Approach 1:
The exposure process is segmented into two separate exposure processes with different illumination conditions. The first exposure uses dipole illumination optimized for width resolution, while the second exposure uses cross-quadrapole illumination optimized for length critical dimension, allowing each exposure to independently optimize for its specific dimensional requirement without compromising the other
Solution Approach 2:
The illumination parameters are changed between two different configurations (dipole and cross-quadrapole) for the two separate exposure processes. This parameter change allows the system to achieve different resolution characteristics for different dimensions, enabling the formation of patterns with desired critical dimensions without sacrificing overall resolution
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 the formation of patterns with high resolution and desired critical dimensions, maintaining image quality and eliminating issues related to mask registration and overlapping noise, while being easily integratable into existing lithography processes.
Implementation Method 1
a first exposure process with the photomask is provided in an exposure system, the first exposure process uses a first light source with a higher resolution that is capable of resolving the second width of each of the second stripe patterns
Implementation Method 2
a second exposure process with the photo-mask is provided in the exposure system, the second exposure process uses a second light source with a lower resolution that is not adequate to resolve the second width of each of the second stripe patterns
Data Source
AI summary
A method of forming a tight-pitched pattern. A target pattern including a plurality of first stripe patterns is provided. Each of the first stripe patterns has a first width and a first length. A photomask includes a plurality of second stripe patterns corresponding to the first stripe patterns is provided. Each of the second stripe patterns has a second width and a second length. A first exposure process with the photomask is provided in an exposure system. The first exposure process uses a first light source with a higher resolution that is capable of resolving the second width of each of the second stripe patterns. Finally, a second exposure process with the photo-mask is provided in the exposure system. The second exposure process uses a second light source with a lower resolution that is not adequate to resolve the second width of each of the second stripe patterns.