Hot Edge Ring Sloped Surface Plasma Uniformity
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Solution Overview
Problem
Plasma etch conditions in semiconductor processing chambers cause significant ion bombardment and nonuniform etch rates across semiconductor substrates, leading to erosion, corrosion, and increased costs due to the short lifetime of consumable parts like the hot edge ring.
Innovation Solution
A hot edge ring with a sloped upper surface is designed to surround the semiconductor substrate, providing an optimized RF impedance path and shielding from plasma attack, made from low-resistivity boron-doped single-crystalline silicon or CVD SiC, with specific dimensions and features to extend its RF lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hot edge ring is used to control etch rate uniformity, then etch rate uniformity is improved, but the ring suffers from erosion and corrosion reducing its lifetime
Solution Approach 1:
The patent changes the geometric parameters of the hot edge ring by introducing a sloped upper surface instead of a flat surface. This parameter change modifies how the ring interacts with plasma and substrates, reducing erosion while maintaining etch rate uniformity control
Solution Approach 2:
The patent specifies using low-resistivity boron-doped single-crystalline silicon or CVD SiC materials for the hot edge ring. These composite material choices provide both the electrical properties needed for RF coupling and enhanced resistance to plasma erosion and corrosion
2Reliability
If the hot edge ring is made consumable for regular cleaning, then plasma exposure effects are managed, but cost of ownership increases
Solution Approach 1:
The patent acknowledges the hot edge ring as a consumable part but extends its service life through design modifications. The sloped surface and material choices make it more durable while maintaining the consumable nature for eventual replacement when necessary
Solution Approach 2:
By changing the geometric parameters (sloped surface) and material properties (low-resistivity boron-doped silicon or CVD SiC), the patent extends the operational lifetime of the ring, reducing the frequency of replacement and thereby decreasing cost of ownership
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 hot edge ring with a sloped upper surface enhances plasma uniformity and extends its operational life, reducing the frequency of cleaning or replacement, thereby decreasing the cost of ownership and improving etch rate uniformity across the substrate.
Implementation Method 1
the sloped upper surface shapes the plasma sheath such that the lifetime of the hot edge ring is optimally extended
Implementation Method 2
A radio frequency (RF) power is applied between the electrodes to excite a process gas into a plasma for processing semiconductor substrates
Data Source
AI summary
A hot edge ring with extended lifetime comprises an annular body having a sloped upper surface. The hot edge ring includes a step underlying an outer edge of a semiconductor substrate supported in a plasma processing chamber wherein plasma is used to process the substrate. The step includes a vertical surface which surrounds the outer edge of the substrate and the sloped upper surface extends upwardly and outwardly from the upper periphery of the vertical surface.