Dielectric Plasma Nozzle for Wafer Edge Bead Removal
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Solution Overview
Problem
Current edge bead removal methods in semiconductor wafer processing are inefficient due to high chamber pressure cycling, wafer heating and cooling times, and the use of expensive hardware. Additionally, existing plasma cutters can damage wafers and cause metal contamination.
Innovation Solution
A nozzle-based plasma jet system using RF-powered plasma nozzles with dielectric barriers to prevent arcing and metal contamination, combined with wafer rotation for comprehensive edge processing. The system generates radicals for efficient edge bead removal without delivering arcs to the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If DC-arc plasma cutters are used for edge bead removal, then cutting capability is achieved, but metal contamination occurs and wafers are damaged
Solution Approach 1:
The patent introduces a dielectric barrier as an intermediary between the plasma source and the wafer surface. This dielectric layer prevents direct contact between the plasma and wafer, thereby eliminating metal contamination and wafer damage while maintaining effective edge bead removal capability
Solution Approach 2:
The patent replaces the mechanical DC-arc cutting system with a non-contact plasma-based system. By using RF-powered plasma generation through dielectric barriers, the system eliminates the need for physical arc contact, thus preventing metal contamination and wafer damage
2Power
If conventional plasma nozzles are used, then plasma generation is achieved, but arcing and metal contamination occur
Solution Approach 1:
The dielectric barrier serves as a mediator between the electrodes and the plasma environment, preventing arc formation and metal particle generation while allowing RF power to effectively generate plasma for edge bead removal
Solution Approach 2:
The dielectric barrier creates a non-conductive environment that prevents arcing, effectively establishing an 'inert' electrical environment that eliminates harmful discharge phenomena while maintaining plasma generation capability
3Productivity
If high power density plasma is applied, then etch rate is improved, but thermal damage may occur
Solution Approach 1:
The dielectric barrier acts as a thermal buffer that allows high power density plasma to be applied to the wafer edge while preventing excessive heat transfer that would cause thermal damage to the wafer substrate
Solution Approach 2:
The system controls plasma parameters including power density, gas flow rates, and exposure time to optimize etch rate while maintaining wafer integrity. The dielectric barrier enables these parameter adjustments without causing thermal runaway
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 system achieves fast edge bead removal with constant heating and cooling, supports high power density plasma without thermal or chemical damage, and offers substantial cost savings in hardware. It ensures high etch rates and long nozzle life, preventing contamination and extending operational temperatures.
Implementation Method 1
A radio frequency (RF) power source is coupled to the nozzle and is configured to provide RF power to generate plasma of the first gas in the first channel defined between the first electrode and the second electrode
Implementation Method 2
The plasma nozzle design uses a dielectric barrier to metal surfaces so as to prevent arcing and metal contamination
Implementation Method 3
The radicals are then directed toward the wafer by means of a pressurized jet flow
Implementation Method 4
The plasma nozzle is powered by radio frequency (RF) power that can support powers and high heat loads
Data Source
AI summary
Systems and device for removing edge bead accumulated on an edge of a wafer includes a first electrode disposed in a center of a nozzle used within a process chamber and a second electrode embedded within a dielectric material that surrounds the first electrode. A first channel is defined between the first electrode and the dielectric material and is used to receive a first gas from a first gas source. A second channel is defined between the dielectric material and an outer wall of the nozzle and is used to receive a second gas. RF power source is coupled to the nozzle so as to provide RF power to the electrodes to generate plasma radicals of the first gas. An opening at a bottom of the nozzle is used to provide pressurized flow of plasma radicals toward an edge of the wafer positioned below the nozzle.