OPC Model Selection for Photo Mask Fabrication
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Solution Overview
Problem
Current optical proximity correction (OPC) methods for fabricating photo masks rely heavily on engineers' experience, leading to inefficiencies and increased costs due to the selection of inappropriate OPC models, which can result in distorted images and prolonged fabrication times.
Innovation Solution
A method that automatically selects an optimized OPC model by analyzing data from a preliminary mask layout using an integrated circuit (IC) layout, contour images, and optical models, applying resolution enhancement technologies, and generating analysis data to determine the most suitable OPC model for the specific mask layout, thereby reducing dependence on engineers' experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rule-based OPC methods are used to process layout data, then operating speed is improved, but manufacturing precision deteriorates due to inability to correct layout based on simulation results
Solution Approach 1:
The OPC process is divided into two distinct stages: a fast rule-based pre-processing stage that handles overall layout modifications, and a subsequent model-based refinement stage that applies simulation results to critical patterns. This segmentation allows the system to benefit from both the speed of rule-based methods and the precision of model-based correction.
Solution Approach 2:
The patent applies different OPC methodologies to different regions of the layout based on their importance and complexity. Critical patterns that require high precision undergo model-based correction with simulation validation, while less critical areas use faster rule-based methods. This local differentiation optimizes both speed and precision where needed.
2Manufacturing precision
If model-based OPC methods are used to correct mask pattern deformation, then manufacturing precision is improved, but productivity deteriorates due to larger required operation time
Solution Approach 1:
The system performs preliminary rule-based OPC corrections on the entire layout before applying model-based corrections. This preliminary action removes obvious errors and prepares the layout for more targeted, efficient model-based refinement, reducing the overall computation time required for high-precision correction.
Solution Approach 2:
Instead of applying computationally intensive model-based corrections to the entire layout, the patent applies them selectively to only those critical patterns that require high precision. This partial application of the more accurate method maintains manufacturing precision for critical features while significantly reducing overall operation time.
3Ease of operation
If engineers rely on experience to select OPC models, then ease of operation is maintained, but manufacturing precision deteriorates due to selection of inappropriate models
Solution Approach 1:
The system automatically evaluates and selects the most appropriate OPC model by analyzing the specific characteristics of the input layout patterns. This self-service capability eliminates the need for engineers to manually select models based on experience, ensuring that the most suitable model is automatically chosen for each specific case, thereby improving precision without complicating operation.
Solution Approach 2:
The patent incorporates a feedback mechanism where simulation results are used to evaluate the performance of different OPC models on the specific layout. This feedback loop allows the system to automatically identify and select the model that produces the best correction results for the given patterns, ensuring high manufacturing precision while maintaining ease of operation.
Data Source
AI summary
Provided is a method of fabricating a photo mask. The method includes preparing a model group including optical proximity correction (OPC) models and generating a preliminary mask layout using an integrated circuit (IC) layout. A contour image may be produced from the preliminary mask layout through a simulation using an optical model. Subsequently, the preliminary mask layout may be compared with the contour image and the comparison result may be analyzed to produce analysis data for providing criteria used in selecting an OPC model. An OPC model suitable for the preliminary mask layout may be selected from the model group based on the analysis data. An OPC process may be performed on the preliminary mask layout using the selected OPC model to generate a mask layout.