Model-Based Lithography Guided Layout for Sub-Resolution Assist Features
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Solution Overview
Problem
The lithography process faces challenges in maintaining adequate process margins and feature sharpness as feature sizes approach sub-wavelength scales, requiring aggressive reduction of the k1 factor and increased use of Resolution Enhancement Techniques (RET), which are costly and time-consuming, especially for advanced mask sets.
Innovation Solution
A model-based lithography guided layout (LGL) method that iteratively determines the optimal placement of target features within the mask design using Simulation Guidance Maps (SGM) and Layout Guidance Maps (LGM) to enhance imaging performance, improving process window and design manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Resolution Enhancement Techniques (RET) are applied to maintain imaging performance at sub-wavelength scales, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies preliminary action by performing model-based lithography guided layout during the design phase to pre-optimize feature placement and determine optimal assist feature positions before actual lithography. This iterative process uses simulation guidance maps to predict and correct potential imaging issues in advance, reducing the need for complex post-lithography corrections and extensive RET applications during manufacturing.
2Manufacturing precision
If aggressive reduction of the k1 factor is applied to achieve smaller feature sizes, then manufacturing precision is improved, but loss of time and process stability worsen
Solution Approach 1:
The patent implements feedback by using model-based lithography simulation to continuously monitor and adjust the lithography process parameters. The simulation guidance maps provide real-time feedback on how design changes affect imaging performance, allowing iterative optimization of feature placement and process parameters to maintain precision while expanding the process window and reducing time loss.
3Manufacturing precision
If extensive RET applications are applied to optimize mask patterns, then manufacturing precision is improved, but productivity decreases due to increased processing time and cost
Solution Approach 1:
The patent applies preliminary action by performing model-based lithography guided layout during the design phase to pre-optimize feature placement and determine optimal assist feature positions before actual lithography. This iterative process uses simulation guidance maps to predict and correct potential imaging issues in advance, reducing the need for complex post-lithography corrections and extensive RET applications during manufacturing.
Solution Approach 2:
The patent implements self-service by using the lithography simulation model to automatically generate design recommendations and layout optimizations. The system self-adjusts feature placements and assist feature positions based on simulated imaging performance, reducing the need for manual intervention and extensive iterative RET processing, thereby improving productivity while maintaining precision.
Data Source
AI summary
Methods are disclosed to create efficient model-based Sub-Resolution Assist Features (MB-SRAF). An SRAF guidance map is created, where each design target edge location votes for a given field point on whether a single-pixel SRAF placed on this field point would improve or degrade the aerial image over the process window. In one embodiment, the SRAF guidance map is used to determine SRAF placement rules and/or to fine-tune already-placed SRAFs. The SRAF guidance map can be used directly to place SRAFs in a mask layout. Mask layout data including SRAFs may be generated, wherein the SRAFs are placed according to the SRAF guidance map. The SRAF guidance map can comprise an image in which each pixel value indicates whether the pixel would contribute positively to edge behavior of features in the mask layout if the pixel is included as part of a sub-resolution assist feature.