Plasma Etching Simulation Using Flux-Based Control Index
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Solution Overview
Problem
Existing simulation methods for plasma etching in semiconductor processing require unique control indices for each processing apparatus, making it impractical to control multiple apparatuses uniformly, and prioritize process conversion difference over damage reduction, leading to limited control flexibility.
Innovation Solution
A simulation method and program that calculate a common control index using the flux amount of reaction products, etching rate, dissociation fraction, solid angle, and aperture ratio to evaluate and control the shape of a wafer surface, allowing for uniform control across multiple processing apparatuses and prioritizing both process conversion difference and damage reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If unique control indices are used for each processing apparatus based on monitoring values in plasma state, then the control precision for individual apparatus is improved, but the adaptability to control multiple apparatuses uniformly deteriorates
Solution Approach 1:
The patent introduces a universal control index (flux amount of reaction products) that can be applied across multiple processing apparatuses. Instead of using apparatus-specific monitoring values, the invention calculates a common flux amount based on process conditions (gas flow rate, pressure, power) that serves all apparatuses uniformly, enabling multi-apparatus control while maintaining precision through standardized parameters.
Solution Approach 2:
The invention changes the control parameter from apparatus-specific monitoring values to process condition-based flux amount calculations. By using fundamental process parameters (gas flow rate, pressure, power) that can be controlled and measured across different apparatuses, the system achieves both precision and adaptability through parameter standardization.
2Manufacturing precision
If process conversion difference control is prioritized using existing simulation methods, then the manufacturing precision of mask pattern shape is improved, but the productivity due to limited control flexibility deteriorates
Solution Approach 1:
The patent enables dynamic control by allowing adjustment of multiple process parameters (gas flow rate, pressure, power) to optimize both process conversion difference and damage reduction. The simulation method dynamically calculates the optimal flux amount by considering the interplay between etching rate, dissociation fraction, and solid angle, providing flexibility to adapt to different process requirements and improve overall productivity.
Solution Approach 2:
The invention changes the control approach from fixed priority (process conversion difference only) to multi-parameter optimization. By simultaneously considering etching rate, dissociation fraction, and solid angle in the flux amount calculation, the system achieves both high precision in mask pattern shape control and improved productivity through flexible parameter adjustment.
3Measurement precision
If calibration curves are created for each apparatus to compare process properties, then the measurement precision between apparatuses is improved, but the device complexity and maintenance burden increase
Solution Approach 1:
The patent extracts the essential control parameter (flux amount of reaction products) from apparatus-specific monitoring systems. Instead of relying on complex calibration curves for each apparatus, the invention calculates the flux amount directly from process conditions (gas flow rate, pressure, power), eliminating the need for apparatus-specific calibration and reducing system complexity while maintaining measurement precision.
Solution Approach 2:
The invention introduces flux amount calculation as an intermediary that bridges multiple processing apparatuses. Instead of directly comparing apparatus-specific monitoring values that require complex calibration, the flux amount serves as a common intermediary parameter derived from standardized process conditions, enabling straightforward comparison and control across different apparatuses.
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
Enables reliable production of semiconductor devices with reduced variability in process conversion difference and damage across multiple processing apparatuses, improving productivity and reducing maintenance frequency while enhancing control flexibility.
Implementation Method 1
performing an etching process using plasma on a surface of a wafer
Data Source
AI summary
A simulation method includes acquiring processing conditions for performing an etching process using plasma on a surface of a wafer covered by a mask having a predetermined mask thickness and aperture ratio, calculating, based on the conditions, a flux amount of a reaction product that enters the surface, calculating, based on mask information including the thickness and the aperture ratio and the flux amount, an etching rate of the wafer, calculating, based on the conditions and the etching rate, a dissociation fraction of the product, calculating, based on the information and the etching rate, a solid angle at a predetermined evaluation point set on the surface, the solid angle corresponding to a view area in which plasma space can be seen from the evaluation point, and calculating, based on the etching rate, the dissociation fraction, the solid angle, and the aperture ratio, a control index for evaluating a surface shape.