Liftable Edge Ring Structure for Uniform Wafer Etching
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Solution Overview
Problem
As semiconductor devices continue to integrate more components into smaller areas, the etching process faces challenges in achieving uniformity and residue formation on the back surface of the edge ring during the etching of semiconductor wafers.
Innovation Solution
An etching system with an edge ring that lifts during the process, creating a gap for etchant flow and preventing residue formation, utilizing a substrate support and edge ring assembly with a top ring lifted to allow etchant passage, ensuring uniformity and preventing material deposition on the edge ring surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the edge ring remains stationary during etching, then the structural simplicity is maintained, but residue formation occurs on the back surface of the edge ring
Solution Approach 1:
The edge ring is designed with a lift mechanism that allows it to transition from a stationary position to a lifted position during the etching process. This dynamic adjustment creates a gap between the edge ring and the substrate support, enabling etchant flow underneath to prevent residue formation while maintaining structural simplicity when not in use
2Object-generated harmful factors
If the top ring is lifted to create a gap for etchant flow, then residue formation is prevented, but the device complexity increases
Solution Approach 1:
The top ring incorporates a lift mechanism that enables controlled vertical movement to create a gap for etchant passage. This dynamic feature prevents material deposition on the edge ring surface while the mechanism remains integrated within the existing assembly structure, minimizing additional complexity
Solution Approach 2:
The lift mechanism acts as an intermediary component between the top ring and the substrate support, mediating the gap creation process. This intermediary structure enables etchant flow control without requiring complete redesign of the edge ring assembly
3Productivity
If minimum feature size is reduced to increase integration density, then more components can be integrated, but etching uniformity becomes more difficult to achieve
Solution Approach 1:
By dynamically lifting the edge ring during etching, the system maintains consistent etchant flow and pressure distribution across the substrate surface. This dynamic adjustment compensates for the challenges of etching smaller features, ensuring uniform etching results even as minimum feature sizes are reduced to increase integration density
Data Source
AI summary
A ring of an edge ring assembly for an etching system and methods of using the ring are described. In some embodiments, the ring includes a top portion including a side surface defining an opening sized to receive a center portion of a substrate support supporting a semiconductor wafer, and the top portion has a first constant thickness. The ring further includes a bottom portion integrally connected to the top portion, and the bottom portion has a second constant thickness that is about 15 percent to about 115 percent of the first constant thickness.