Dual Edge Ring RF Coupling for Plasma Etching Uniformity
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Solution Overview
Problem
Current plasma processing technologies face challenges in maintaining uniformity across larger substrates due to substrate edge effects and polymer deposition, which can lead to defective devices and reduced yield, as they struggle to balance RF coupling for optimal etching and polymer removal.
Innovation Solution
The implementation of a dual edge ring configuration in a plasma processing system, where each edge ring has independent RF coupling to optimize electric potential differences, ensuring uniform etching and effective removal of polymer by-products through controlled arcing on the beveled edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If RF coupling is optimized for maximum etching uniformity, then etching uniformity is improved, but polymer deposition on substrate edge increases
Solution Approach 1:
The single hot edge ring is divided into two separate hot edge rings: a first hot edge ring for etching uniformity control and a second hot edge ring for polymer removal. This segmentation allows independent optimization of each ring's function without compromise.
Solution Approach 2:
Different regions of the substrate edge are treated with different quality characteristics. The first hot edge ring provides controlled RF coupling for uniform etching, while the second hot edge ring provides enhanced RF coupling for polymer removal, creating localized functional differentiation.
2Object-generated harmful factors
If RF coupling to hot edge ring is increased for polymer removal, then polymer cleaning is improved, but etching uniformity deteriorates
Solution Approach 1:
The hot edge ring functionality is segmented into two independent rings, allowing the second ring to handle polymer removal with high RF coupling while the first ring maintains optimal RF coupling for etching uniformity.
Solution Approach 2:
The second hot edge ring applies excessive RF coupling specifically targeted at polymer removal, accepting that this localized excessive action does not compromise the first ring's optimized etching uniformity function.
3Productivity
If substrate size is increased to maximize yield, then manufacturing productivity is improved, but edge effect uniformity deteriorates
Solution Approach 1:
The solution moves from a single-dimension approach (one hot edge ring) to a two-dimension approach (two hot edge rings with different functions), adding functional dimensionality to address edge effects on large substrates.
Solution Approach 2:
Different zones of the substrate edge receive different treatments: the first hot edge ring ensures uniform etching across the edge, while the second hot edge ring specifically addresses polymer deposition issues, creating localized quality optimization for large substrate processing.
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 achieves uniform etching across the substrate edge without sacrificing polymer cleaning, enhancing manufacturing yield by maintaining consistent plasma sheath equipotential lines and preventing polymer deposition on adjacent substrates during transport.
Implementation Method 1
provides a coupling ring to facilitate RE coupling from an ESC (electrostatic chuck) assembly to the first edge ring
Implementation Method 2
maximizing a potential difference between the substrate and the second edge ring to induce arcing on the edge of the substrate
Implementation Method 3
The gases are subsequently ionized to form plasma 104, in order to process (e.g., etch or deposit) exposed areas of substrate 106
Implementation Method 4
hot edge ring (HER) 116 (e.g., Si, etc.) on an electrostatic chuck (ESC) 108
Data Source
AI summary
A method for processing a substrate in a plasma processing chamber is provided. The substrate is disposed above a chuck and surrounded by a first edge ring. The first edge ring is electrically isolated from the chuck. The method includes providing a second edge ring. The second edge ring is disposed below an edge of the substrate. The method also includes providing a coupling ring. The coupling ring is configured to facilitate RF coupling from an ESC (electrostatic chuck) assembly to the first edge ring, thereby causing the first edge ring to have an edge ring potential during substrate processing and causing the RF coupling to be maximized at the first edge ring and minimized at the second edge ring during the substrate processing. The method also includes providing an insulator ring, wherein the second edge ring is disposed above the insulator ring.