OPC Model Calibration for Semiconductor Patterning Precision
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Solution Overview
Problem
The increasing complexity and miniaturization of semiconductor devices require more stringent accuracy in overlay and critical dimension measurements during the patterning process, which existing techniques struggle to achieve due to errors from optical aberration, patterning device heating, and substrate heating, leading to potential device failure.
Innovation Solution
A method involving an optical proximity correction (OPC) model is used to control the patterning process by obtaining and calibrating an OPC model, collecting process control data, and analyzing it to correct imaging errors, with the aid of inspection systems like electron beam inspection apparatuses and lithographic apparatuses to ensure accurate pattern formation on substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing measurement techniques are used during patterning process, then measurement can be performed, but measurement precision deteriorates due to optical aberration, patterning device heating, and substrate heating
Solution Approach 1:
The patent applies preliminary action by performing measurements at multiple stages: before the patterning process (to establish baseline characteristics), during the patterning process (to detect changes in real-time), and after the patterning process (to verify final results). This allows detection and correction of measurement errors caused by optical aberration and thermal effects before they compromise the final measurement precision.
Solution Approach 2:
The patent implements feedback by continuously monitoring measurement characteristics during the patterning process and using this information to adjust process parameters. The system compares measured overlay and critical dimension values against target values, and automatically adjusts illumination, focus, or exposure parameters to compensate for optical aberration and thermal drift, thereby maintaining measurement precision throughout the process.
2Productivity
If miniaturization of semiconductor devices is pursued, then device complexity and functionality increase, but manufacturing precision requirements become more stringent and harder to achieve
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the patterning process using OPC models and performing predictive simulations before actual manufacturing. This allows identification of potential precision issues with miniaturized features beforehand, enabling proactive adjustment of process parameters and measurement strategies to achieve the required manufacturing precision for advanced node devices.
Solution Approach 2:
The patent implements feedback by using real-time measurements of overlay and critical dimension on miniaturized features to dynamically adjust patterning process parameters. The system continuously monitors measurement data and uses closed-loop control to maintain manufacturing precision even as device dimensions shrink and become more sensitive to process variations.
Data Source
AI summary
A method of controlling an imaging process uses a qualified optical proximity correction (OPC) model, the process including obtaining an OPC model that is configured to model the behavior of OPC modifications to a pre-OPC design in a process for forming a pattern on a substrate using a post-OPC design in a patterning process, using the patterning process in a manufacturing environment, collecting process control data in substrates patterned using the patterning process in the manufacturing environment, storing the collected process control data in a database, analyzing, by a hardware computer system, the stored, collected process control data to verify that the OPC model is correcting pattern features within a selected threshold, and for pattern features falling outside the selected threshold, determining a modification to the imaging process to correct imaging errors.