Exposure System Calibration via Dynamic Wafer Segmentation
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Solution Overview
Problem
Conventional techniques for calibrating exposure systems in photolithography processes are time-consuming and expensive, often taking hours to complete, leading to significant downtime in IC fabrication facilities.
Innovation Solution
A method and device for determining focus parameters in exposure systems, which involves partitioning a semiconductor wafer into regions, forming patterns with predefined focus parameters, measuring pattern positions using optical tools, and selecting optimal focus parameters based on measured data, allowing for rapid calibration of exposure systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration techniques are used for exposure machines, then measurement precision can be achieved, but calibration time becomes excessively long (hours)
Solution Approach 1:
The patent segments the calibration process into multiple measurement points across different regions of the wafer (center, intermediate, outer regions with different radius ratios). By dividing the calibration into discrete measurement locations with specific coordinate patterns, the system achieves comprehensive focus parameter determination without requiring exhaustive full-wafer scanning, thus reducing calibration time while maintaining precision.
Solution Approach 2:
The patent implements preliminary actions by first determining wafer-specific parameters (radius, center position) before calibration, then pre-calculating optimal measurement point coordinates based on these parameters. The system also performs preliminary region division and selects measurement points in advance, which streamlines the actual calibration execution and reduces on-the-spot computation time.
2Manufacturing precision
If conventional calibration techniques are used for exposure machines, then accurate focus parameters can be determined, but fabrication downtime increases significantly
Solution Approach 1:
The patent introduces dynamic adaptability by making the measurement point coordinates and region divisions dependent on actual wafer parameters (radius, center position) rather than fixed predetermined values. The system dynamically adjusts the calibration scheme based on each wafer's specific characteristics, optimizing the measurement process for each individual case and reducing unnecessary measurements, thereby improving throughput without sacrificing accuracy.
Solution Approach 2:
The patent changes key parameters of the calibration process: instead of using fixed measurement grids, it varies the number, position, and distribution of measurement points based on wafer parameters. The system modifies calibration parameters (measurement coordinates, region boundaries) to match actual production conditions, enabling faster calibration that maintains accuracy across different wafer types and sizes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces calibration time from hours to minutes, minimizing downtime and maintaining compatibility with conventional processes without substantial equipment modifications, thereby enhancing the efficiency of IC fabrication.
Implementation Method 1
photolithography process is used to define and shape specific areas of the wafer to suit particular design of integrated circuit
Implementation Method 2
measuring the positions of the patterns with an optical measuring device
Data Source
AI summary
Method and system for calibrating exposure system for manufacturing of integrated circuits. According to an embodiment, the present invention provides a method for determining one or more focus parameters for an exposure system. As an example, the exposure system is used for forming patterns on semiconductor wafer. The method includes a step for providing a semiconductor wafer. The semiconductor wafer is characterized by a diameter. The method also includes a step for forming a plurality of patterns using the exposure system on the semiconductor wafer. As an example, each of the plurality of patterns being associated with a focus reference value (e.g., focus distance, focus angle, etc.). The method additionally includes a step for determining a plurality of shift profiles, and each of the shift profile is associated one of the plurality of patterns.