Modified Cell Library for Mask Correction Optimization
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Solution Overview
Problem
Current mask correction processes, such as OPC, are computationally intensive and generate a large volume of data due to the need to account for proximity effects within and between cells in integrated circuit layouts, leading to repeated corrections for the same cell in different placements.
Innovation Solution
The method involves creating a modified library of cells where each cell is partially corrected to compensate for manufacturing effects, with candidate areas identified for further processing, allowing for reduced computational costs by focusing corrections only on these areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If full mask correction is applied to entire cells to compensate for proximity effects, then manufacturing precision is improved, but computational cost and data volume increase significantly
Solution Approach 1:
The patent divides the cell into multiple segments based on proximity effect severity. High-priority segments that require correction are identified and separated from low-priority segments, allowing selective application of mask correction only where needed, thus reducing computational complexity while maintaining manufacturing precision for critical areas
Solution Approach 2:
The patent applies different correction strategies to different regions of the cell. Instead of uniform correction across the entire cell, local quality principles are applied by identifying specific segments with severe proximity effects and applying enhanced correction only to those regions, while using simpler or no correction in other areas
2Manufacturing precision
If repeated mask corrections are performed for the same cell in different placements, then manufacturing precision is maintained, but productivity decreases due to redundant computations
Solution Approach 1:
The patent performs preliminary analysis of the cell to identify segments that require mask correction before actual placement occurs. This preliminary segmentation and priority assignment is done once per cell type, so that when the same cell is placed multiple times in different locations, the pre-computed segmentation can be reused, eliminating redundant computations and improving productivity while maintaining precision
Solution Approach 2:
The patent creates a corrected version of the cell with identified candidate areas that can be copied and reused across multiple placements. Once the mask correction and segmentation is performed for a cell type, the resulting corrected cell model can be instantiated multiple times without repeating the computationally intensive correction process, thus maintaining manufacturing precision while significantly improving productivity
3Device complexity
If candidate areas are identified to focus corrections, then computational cost is reduced, but measurement precision requirements increase to accurately identify correction boundaries
Solution Approach 1:
The patent replaces manual or heuristic methods for identifying candidate areas with automated computational algorithms. Optical proximity correction algorithms and simulation tools are used to automatically identify segments requiring correction based on geometric parameters and proximity effect models, eliminating the need for manual boundary drawing and ensuring consistent, accurate identification of candidate areas across different cells
Data Source
AI summary
An exemplary method for modifying at least part of an integrated circuit layout comprises obtaining an integrated circuit device layout, the integrated circuit device being designed using a library of cells, obtaining a modified library of cells, and replacing at least one cell in the integrated circuit device layout with a corresponding modified cell of the modified library to obtain a modified integrated circuit device layout. The modified library includes modified cells corresponding to cells in the library and candidate areas of each modified cell indicating portions of the cell for further processing. At least some of the modified cells have been modified to at least partially compensate for a manufacturing effect.