Mask Data Synthesis Using Long-Range Correction Maps
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Solution Overview
Problem
The challenge in integrated circuit (IC) design is to accurately calibrate masks and final wafers due to the complexities of semiconductor manufacturing, particularly with the progression to smaller feature sizes, where long-range effects in e-beam lithography pose significant calibration challenges.
Innovation Solution
The method involves generating a layout of test structures to calibrate e-beam model parameters, including long-range effects, and using a pre-computed long-range correction map to compensate for these effects in the mask layout, thereby optimizing the IC design and manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mask proximate correction is performed to compensate for long-range effects, then imaging accuracy is improved, but computational time and processing complexity increase
Solution Approach 1:
The patent pre-computes and stores correction data for long-range effects during mask fabrication. This preliminary action allows the correction to be applied quickly during subsequent lithography processes without requiring time-consuming real-time computations, thus resolving the contradiction between imaging accuracy and computational time.
Solution Approach 2:
The patent introduces an intermediary correction map or lookup table that stores pre-computed correction values. This intermediary structure enables fast retrieval and application of corrections during lithography, avoiding the need for complex real-time calculations while maintaining imaging accuracy.
2Manufacturing precision
If e-beam lithography is used for mask fabrication, then manufacturing precision is improved, but long-range effects cause calibration difficulties
Solution Approach 1:
The patent implements a feedback mechanism where measured calibration data from test structures is used to adjust and refine the e-beam lithography process parameters. This feedback loop enables continuous improvement of calibration accuracy, resolving the contradiction between manufacturing precision and calibration difficulty.
Solution Approach 2:
The patent replaces complex mechanical calibration adjustments with computational corrections applied through software. By substituting physical calibration mechanisms with digital correction models, the system maintains high precision while simplifying the calibration process and reducing its complexity.
3Productivity
If feature sizes are reduced for higher performance, then circuit performance is improved, but imaging and calibration become more challenging
Solution Approach 1:
The patent dynamically adjusts lithography process parameters such as exposure dose, focus, and beam energy based on the specific feature sizes being fabricated. These parameter changes enable the system to maintain imaging precision across different feature size ranges, supporting the transition to smaller features for higher performance circuits.
Data Source
AI summary
A method for mask data synthesis and mask making includes calibrating an optical proximity correction (OPC) model by adjusting a plurality of parameters including a first parameter and a second parameter, wherein the first parameter indicates a long-range effect caused by an electron-beam lithography tool for making a mask used to manufacture a structure, and the second parameter indicates a geometric feature of a structure or a manufacturing process to make the structure, generating a device layout, calculating a first grid pattern density map of the device layout, generating a long-range correction map, at least based on the calibrated OPC model and the first grid pattern density map of the device layout, and performing an OPC to generate a corrected mask layout, at least based on the generated long-range correction map and the calibrated OPC model.