Bevel Etch Repeatability via Optical Edge Characterization
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving consistent bevel etch repeatability across substrates with varying bevel edge profiles, leading to inconsistent material removal and potential contamination, which affects device yield.
Innovation Solution
An optical arrangement is used to characterize the bevel edge profile and thickness of substrates, providing feed-forward information to adjust process parameters such as bevel etch time, chemistry, electrode gap, and RF power to ensure consistent etch results across substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bevel etch steps are interleaved to remove accumulated material at the substrate edge, then device yield is improved by preventing material flake-off, but etch process repeatability deteriorates due to variations in pre-bevel etch substrate profiles
Solution Approach 1:
The system performs preliminary characterization of the substrate bevel edge profile using optical arrangements before the bevel etch process. This advance measurement allows the system to determine feed-forward correction parameters that compensate for substrate-to-substrate variations, ensuring consistent etch results across different substrates while maintaining the benefits of material removal at the edge region
Solution Approach 2:
The system implements a feedback mechanism where optical measurements of the substrate bevel edge profile are used to dynamically adjust bevel etch process parameters. The measured profile information feeds into a control system that modifies etch conditions in real-time, compensating for variations in substrate profiles and achieving repeatable etch results despite inherent substrate differences
2Manufacturing precision
If feed-forward correction parameters are used to adjust process parameters based on optical characterization, then bevel etch repeatability is improved across substrates, but device complexity increases due to additional measurement and control systems
Solution Approach 1:
The optical arrangement serves multiple functions: it characterizes the substrate bevel edge profile, provides feed-forward correction parameters, and enables real-time process adjustment. This multi-functional approach consolidates measurement and control capabilities into a single integrated system, reducing overall complexity while achieving improved etch repeatability
Solution Approach 2:
The system uses the substrate's own optical characteristics to generate the correction parameters needed for its processing. The bevel edge profile measurement directly informs the feed-forward correction applied to that specific substrate, allowing each substrate to self-correct for its unique variations without requiring complex external intervention
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 bevel etch repeatability by compensating for pre-bevel etch variations, reducing material removal inconsistencies and minimizing contamination, thereby enhancing device yield and process reliability.
Implementation Method 1
An optical arrangement is used to characterize the bevel edge profile and thickness of substrates
Implementation Method 2
a bevel etch apparatus is employed to form a ring-shaped plasma near the periphery of the substrate to etch away some of the accumulated material at the substrate's outer edge
Data Source
AI summary
A method, performed in connection with bevel etching of a substrate, for improving bevel-etch repeatability among substrates, is disclosed. The method includes providing an optical arrangement and ascertaining at least one bevel edge characteristic of a bevel edge of said substrate. The method also includes deriving at least one compensation factor from said at least one bevel edge characteristic, said at least one compensation factor pertaining to an adjustment in a bevel etch process parameter. The method further includes performing said bevel etching utilizing said at least one compensation factor.