Etching Process Control via Pattern Width Measurement
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Solution Overview
Problem
The challenge in semiconductor manufacturing is controlling process dispersion during etching processes for forming fine patterns, which becomes increasingly difficult as design rules tighten and photolithography resolution limits are approached, leading to variations in pattern formation.
Innovation Solution
A method involving the formation of hard mask patterns with line and assistant patterns, where the width between openings is measured and used to control the etching process, adjusting parameters like etching time, etchant amount, or etchant type to ensure precise pattern formation, employing advanced process control techniques to manage process dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography resolution limits are approached to form finer patterns, then pattern precision is improved, but process dispersion increases leading to variations in pattern formation
Solution Approach 1:
The patent applies preliminary action by forming a lower pattern with openings before the main etching process. This lower pattern serves as a pre-established reference structure that guides subsequent etching operations. The width of this lower pattern is measured and used to control the etching process, ensuring that the final pattern dimensions are consistent even when approaching photolithography resolution limits.
Solution Approach 2:
The patent implements feedback control by measuring the width of the lower pattern and using this measurement to adjust and control the etching process parameters. The measured width value provides real-time information about the actual pattern dimensions, which is then fed back to modify the etching process to achieve the desired final pattern precision and reduce process dispersion.
2Manufacturing precision
If etching process parameters are adjusted to improve pattern uniformity, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The patent applies self-service by having the lower pattern itself provide the reference for controlling the etching process. The lower pattern's width is measured and used to automatically adjust the etching parameters, eliminating the need for external complex control systems. The process uses its own output (the lower pattern dimensions) to regulate itself, simplifying the overall control architecture while maintaining high precision.
3Manufacturing precision
If multiple etching steps are performed to achieve fine patterns, then pattern precision is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary action by forming the lower pattern with its specific width before the main etching process. This pre-formed structure serves as a template that guides the subsequent etching operations, allowing for precise pattern formation in fewer steps. The lower pattern's dimensions are used to control the etching process, reducing the need for multiple iterative etching steps and thereby decreasing total processing time while maintaining precision.
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 improves the uniformity and precision of pattern formation, reducing defects and ensuring that the desired width between fine patterns is maintained, thereby preventing bridge formation between adjacent patterns.
Implementation Method 1
controlling a process recipe of an etching process for forming the lower pattern
Data Source
AI summary
A method of controlling an etching process for forming fine patterns of a semiconductor device includes forming a lower pattern having a plurality of openings on a substrate, obtaining a width value of the lower pattern, and controlling a process recipe of an etching process for forming the lower pattern by using the width value.