In Situ Etch Compensation for IC Critical Dimension Control
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Solution Overview
Problem
Conventional methods for controlling critical dimensions in integrated circuit manufacturing are inefficient as they require post-etching measurement and feedback, leading to delayed corrections and reduced throughput, especially as feature sizes shrink.
Innovation Solution
An in-situ size controlling method that integrates measurement and compensation etching within the same etching tool, allowing for real-time adjustment of etching conditions to align feature sizes with specifications, using a tri-layer mask structure and nitrogen-free anti-reflective layers to ensure precise control of trench dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional post-etching measurement and feedback is used to control critical dimensions, then measurement precision can be achieved, but productivity decreases due to delayed corrections and reduced throughput
Solution Approach 1:
The patent performs measurement and compensation etching before the hard mask layer etching is complete. By measuring the opening size in the mask layer early in the process and performing compensation etching while still in the same etching tool, the system enables real-time corrections without waiting for post-etching measurement, thus maintaining both measurement precision and productivity
Solution Approach 2:
The system implements real-time feedback by measuring the opening size after initial etching and using this measurement to adjust subsequent etching parameters. The measured critical dimension data is fed back to control the compensation etching process, enabling dynamic adjustment that maintains precision while avoiding the throughput loss of conventional post-etching feedback loops
2Productivity
If real-time measurement and compensation etching is performed within the same etching tool, then productivity improves through immediate corrections, but device complexity increases
Solution Approach 1:
The etching tool is designed with multi-functionality, serving both as an etching device and as a measurement device. By integrating the metrology tool within the etching tool, the system eliminates the need for separate measurement equipment and process steps, thereby improving productivity without proportionally increasing overall system complexity
Solution Approach 2:
The patent merges the measurement function and etching function into a single integrated tool. The metrology tool and etching tool are combined so that measurement and compensation etching can be performed sequentially in the same device, reducing the number of tool transitions and process steps while maintaining real-time control capability
3Area of moving object
If feature sizes are reduced to increase circuit density, then area decreases for higher integration, but manufacturing precision becomes increasingly difficult to control
Solution Approach 1:
The system performs preliminary measurement of the opening size before the hard mask layer etching is completed. By measuring early and performing compensation etching while still in the same tool, the system establishes precise dimensional control before subsequent processing steps, which is critical for maintaining manufacturing precision at reduced feature sizes
Solution Approach 2:
The system dynamically adjusts etching parameters based on real-time measurement data. By changing etching conditions (such as power, gas flow, or etch chemistry) based on the measured opening size, the system compensates for variations and maintains precise critical dimension control even as feature sizes are reduced for higher density
Data Source
AI summary
A method includes performing an etching on a mask layer to form an opening in the mask layer. The mask layer is a part of a wafer. The method further includes measuring a lateral size of the opening, comparing the lateral size of the opening with a specified range, and performing a compensation etch to compensate for a difference between the lateral size and the specified range. After the compensation etch, a target layer of the wafer is etched to extend the opening into the target layer.