Multiscale Plasma Etch Modeling for Asymmetry and Overlay Control
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Solution Overview
Problem
Existing plasma modeling techniques are resource-intensive, time-consuming, and fail to account for crosstalk between multiple length scales, leading to etch-induced asymmetry and overlay errors in semiconductor processing.
Innovation Solution
A multi-scale plasma etch model that predicts plasma characteristics at wafer and die scales, using Gaussian kernels to simulate etch profiles and mitigate asymmetries by considering pattern density gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching is used to achieve high aspect ratio patterns, then pattern transfer fidelity is improved, but etch-induced asymmetry and overlay errors occur
Solution Approach 1:
The patent changes the parameters of plasma particles (energy, angle of incidence, trajectory) by modeling their behavior across multiple length scales. This allows optimization of etching conditions to maintain vertical profiles while reducing asymmetry effects on alignment features.
Solution Approach 2:
The patent introduces a multi-scale physical model as an intermediary between plasma process parameters and etch outcomes. This model accounts for crosstalk between length scales to predict and mitigate asymmetry before it affects alignment accuracy.
2Loss of information
If existing physical modeling techniques are used for plasma etching, then process understanding is improved, but computational resource consumption and time increase
Solution Approach 1:
The patent segments the plasma etch modeling into multiple length scales (wafer-scale, die-scale, feature-scale). Each scale is modeled separately with appropriate parameters, allowing efficient computation while capturing cross-scale effects that improve process understanding.
Solution Approach 2:
The patent adds the dimension of multiple length scales to the modeling approach. By considering phenomena at different scales simultaneously, the model achieves better process understanding without proportional increases in computational cost, as each scale can be treated with appropriate approximations.
3Manufacturing precision
If existing modeling techniques account for multiple length scales, then crosstalk effects are captured, but model complexity and computational cost increase
Solution Approach 1:
The patent divides the complex multi-scale modeling problem into segmented components (wafer-scale plasma distribution, die-scale pattern density effects, feature-scale etch physics). This segmentation reduces model complexity by allowing each component to be modeled with appropriate level of detail and approximation.
Solution Approach 2:
The patent applies local quality by using different modeling approaches for different spatial locations and scales. Wafer-scale effects use continuum approximations, die-scale effects use pattern density maps, and feature-scale effects use detailed kinetic models, optimizing the balance between accuracy and complexity.
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
Enhances the accuracy of plasma etch simulations by accounting for crosstalk between length scales, reducing etch-induced asymmetry and overlay errors, thereby improving process yield and efficiency.
Implementation Method 1
plasma processes to obtain the necessary pattern transfer fidelity
Implementation Method 2
etching must be anisotropic, i.e., much faster perpendicular than parallel to the surface
Implementation Method 3
predicting an electric potential gradient between the identified first and the second regions; and predicting the second characteristic of the charged particle based on the electric potential gradient
Implementation Method 4
predicting a concentration gradient of an etchant between the identified first and the second regions, predicting a diffusion flux of the etchant based on the concentration gradient
Data Source
AI summary
Systems and methods for simulating a plasma etch process are disclosed. According to certain embodiments, a method for simulating a plasma etch process may include predicting a first characteristic of a particle of a plasma in a first scale based on a first plurality of parameters; predicting a second characteristic of the particle in a second scale based on a modification of the first characteristic caused by a second plurality of parameters; and simulating an etch characteristic of a feature based on the first and the second characteristics of the particle. A multi-scale physical etch model or a multi-scale data driven model may be used to simulate the plasma etch process.