Pattern-Density Etch Control Using Adaptive Gas Flow Ratios
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Solution Overview
Problem
Variations in pattern density during semiconductor manufacturing cause issues with etch rate, uniformity, and selectivity, leading to undesirable residues or over etch, which can result in defects such as shorts between trenches.
Innovation Solution
An automated process for selecting etch process parameters based on pattern density, adjusting etchant gas ratios and other parameters to maintain etch quality and efficiency across varying pattern densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etch process is tuned for higher densities, then etch rate is improved for high density regions, but residues remain at sidewall trenches in low density regions due to trapped polymers
Solution Approach 1:
The patent implements dynamic adjustment of etch process parameters based on pattern density. The system automatically modifies etch chemistry, power, pressure, and temperature in real-time according to the specific pattern density being processed, transitioning from static to dynamic process control to prevent both residues and over-etching
Solution Approach 2:
The patent changes multiple etch process parameters including gas flow rates, pressure, power, and temperature based on pattern density measurements. By adjusting these parameters dynamically, the system optimizes etch rate and polymer formation control for each specific pattern density, eliminating residues in low density regions while maintaining adequate etch rate in high density regions
2Object-generated harmful factors
If an etch process is tuned for lower densities using a more reactive etch, then residues are reduced in low density regions, but over etch occurs in high density regions causing punch through effects
Solution Approach 1:
The patent dynamically adjusts etch parameters including reducing power and modifying gas chemistry when processing high density patterns to prevent over-etching and punch-through effects, while maintaining sufficient etch rate through optimized parameter combinations
Solution Approach 2:
The system uses real-time monitoring and feedback control to detect pattern density variations and automatically adjust etch parameters during the process, preventing over-etching in high density regions by continuously comparing actual etch progress with target specifications
3Device complexity
If a single etch process is used for all pattern densities, then device complexity is reduced, but etch quality and uniformity deteriorate across different density regions
Solution Approach 1:
The patent implements a dynamic etch process that automatically adapts parameters based on detected pattern density, creating a unified yet adaptive process that maintains high etch quality across varying densities without requiring multiple separate process recipes
Solution Approach 2:
The patent creates a universal etch process platform that can handle multiple pattern densities through automated parameter adjustment, making a single etch tool and process flow capable of performing multiple functions that would traditionally require different specialized processes
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
The automated process ensures high-quality etch results with reduced human intervention, improving fabrication efficiency and reducing defects by optimizing etch processes for different pattern densities.
Implementation Method 1
a ratio of plasma etchant gases is automatically selected for use in an etch process
Implementation Method 2
The selected ratio of plasma etchant gases is used to etch features into a material layer on the workpiece
Data Source
AI summary
Techniques, structures, and systems related to etch processing using automated selection of etch parameters are discussed. Patterns of features having differing pattern densities are etched into underlying material layers having the same or similar characteristics such as material composition, thickness, etc. While other process parameters remain substantially constant, gas flows, as defined by a gas flow ratio, of etchant gases are automatically selected from available or selectable gas flow ratios using the pattern densities. The ratio of gas flows increases monotonically with increasing pattern density.