Decision Tree Prediction Model Signal-to-Noise Ratio

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Solution Overview

Problem

Developing robust and generalized prediction models in semiconductor manufacturing is challenging due to high noise levels, correlated data, and a large number of input variables, which makes it difficult to identify key variables affecting yield and device performance.

Innovation Solution

A method and system that iteratively execute a decision tree-based prediction model with varying weights assigned to input variables, using a Rules Ensemble algorithm to filter out non-influential variables and identify key input variables, thereby increasing the signal-to-noise ratio and reducing the complexity of the variable list.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If advanced statistical methods are used to build high fidelity prediction models with all input variables, then model accuracy may be improved, but the complexity of the model increases and it becomes difficult to identify key variables due to high noise levels and multicollinearity

Engineering Contradiction:
Improveprediction model accuracyVSAvoidmodel complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the large set of input variables into two distinct groups: key variables (signal) and non-key variables (noise). This segmentation is achieved through iterative execution of prediction models with varying weights, allowing the system to identify and separate influential variables from non-influential ones. The segmentation resolves the contradiction by maintaining model accuracy through inclusion of all variables while organizing them into manageable groups that reduce apparent complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts key variables from the complete set of input variables by iteratively executing prediction models with different weight assignments. This extraction process isolates the signal (key variables) from the noise (non-key variables), creating a reduced variable list that maintains prediction accuracy while reducing model complexity and improving interpretability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If heuristics and past knowledge are used to reduce the input variable list, then model complexity is reduced, but the process becomes time consuming and prone to errors

Engineering Contradiction:
Improvevariable list complexityVSAvoidvariable selection time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent implements a self-service mechanism where the prediction model automatically identifies and ranks key variables through iterative execution with varying weights. This automated process eliminates the need for manual heuristic-based variable selection, reducing both time consumption and human error while systematically reducing variable list complexity.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If all input variables are included in the prediction model, then comprehensive coverage is achieved, but the signal to noise ratio decreases making it difficult to identify key variables

Engineering Contradiction:
Improvevariable coverageVSAvoidsignal to noise ratio
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent employs feedback through iterative execution of the prediction model with varying weights assigned to input variables. Each iteration provides feedback on variable importance, allowing the system to accumulate information about which variables are key and which are non-key. This feedback mechanism maintains comprehensive variable coverage while progressively improving the signal to noise ratio by identifying influential variables.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS9275334B2Increasing signal to noise ratio for creation of generalized and robust prediction models
Publication Date: 2016.03.01 APPLIED MATERIALS INC
  • US9275334B2 patent drawing
  • US9275334B2 patent drawing
  • US9275334B2 patent drawing

AI summary

A computer system iteratively executes a decision tree-based prediction model using a set of input variables. The iterations create corresponding rankings of the input variables. The computer system generates overall variables contribution data using the rankings of the input variables and identifies key input variables based on the overall variables contribution data.