Gas Distribution Orifice Design for Plasma Damage Reduction
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Solution Overview
Problem
Current gas distribution assemblies in semiconductor processing chambers suffer from plasma damage to o-rings due to insufficient pressure to extinguish the plasma, leading to non-uniform gas exposure and defects in semiconductor devices.
Innovation Solution
The design incorporates a gas distribution assembly with specific orifice configurations, including straight and angled orifices, which increase pressure at the o-ring interface to extinguish the plasma prior to reaching the o-rings, thereby reducing plasma damage and jetting effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diameter of the gas flow hole is reduced to increase pressure at the o-ring interface, then plasma is extinguished and o-ring damage is reduced, but gas velocity increases causing jetting that compromises on-wafer film uniformity
Solution Approach 1:
The gas distribution assembly is divided into multiple separate gas flow holes (orifices) distributed across the faceplate. Each orifice delivers gas to a specific region, allowing independent optimization of pressure and flow velocity for each location. This segmentation enables the system to maintain high pressure at o-ring interfaces to extinguish plasma while controlling gas velocity to prevent jetting effects on the wafer surface.
Solution Approach 2:
Different regions of the gas distribution assembly have different orifice characteristics (diameter, depth, orientation) tailored to local requirements. Orifices near o-ring interfaces are designed to generate high pressure to extinguish plasma, while orifices directing gas toward the wafer are optimized to control flow velocity and prevent jetting. This local customization resolves the contradiction by allowing each region to have the pressure and flow characteristics it needs.
2Quantity of substance
If current orifice designs with diameter of approximately 2 mm and height of approximately 9 mm are used, then gas flow is sufficient, but pressure at the o-ring location is only 3-4 Torr which is insufficient to extinguish plasma
Solution Approach 1:
The orifice parameters (diameter, depth, orientation) are changed to alter the pressure distribution and flow characteristics. By reducing orifice diameter and adjusting depth-to-diameter ratios, the system achieves higher local pressure at o-ring interfaces to extinguish plasma while maintaining sufficient overall gas flow rate to the wafer through the distributed array of orifices.
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 design effectively reduces or eliminates plasma damage to o-rings, maintains film uniformity, and enhances the overall performance of semiconductor processing by achieving the required pressure to extinguish the plasma.
Implementation Method 1
increase pressure at the o-ring interface to extinguish the plasma prior to reaching the o-rings
Implementation Method 2
the absolute pressure at a location of the at least one o-ring is greater than or equal to 10 Torr to extinguish the plasma
Data Source
AI summary
Gas distribution assemblies for semiconductor devices are described. The gas distribution assemblies include a backplate, a faceplate, a counterbored hole, and at least one orifice. The at least one orifice includes, for example, at least one straight orifice, or at least two angled orifices. Some embodiments of the gas distribution assemblies provide for reduced plasma damage in a processing chamber. Some embodiments of the gas distribution assemblies provide for reduced jetting on a substrate in a processing chamber. Methods of reducing plasma damage in gas distribution assemblies are also described.