Gas Feed Insert with Non-Line-of-Sight Bore Path
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Solution Overview
Problem
In plasma processing systems, especially those with an energized upper electrode, unwanted plasma formation occurs in gas feed passages due to electric fields, leading to unpredictable processes and premature component erosion.
Innovation Solution
A gas feed insert with non-aligned bores and external cross-channels creates a non-line-of-sight path for gas flow, preventing plasma formation and protecting electrode components by using small cross-sectional dimensions and varying outer diameters to prevent plasma ignition and sustainment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the upper electrode is energized with RF energy to process substrates, then substrate processing capability is improved, but unwanted plasma formation occurs in gas feed passages due to electric fields
Solution Approach 1:
The gas feed passage is segmented into multiple sections with varying outer diameters along its length. The passage transitions from a larger diameter first section to a smaller diameter second section, creating zones with different electric field characteristics that prevent plasma formation while maintaining gas flow capability
Solution Approach 2:
Different sections of the gas feed passage are given different local properties - the first section has a larger outer diameter for gas introduction, while the second section has a smaller outer diameter to reduce electric field exposure. This local variation in geometry allows the passage to simultaneously handle gas flow and resist plasma formation in different locations
2Reliability
If gas feed passages are made smaller to prevent plasma formation, then plasma confinement is improved, but gas flow delivery capability may be reduced
Solution Approach 1:
The passage is divided into segments with different diameters - a larger first section for adequate gas flow introduction and a smaller second section for plasma prevention. This segmentation allows each section to optimize for its specific function while working together to achieve both goals
Solution Approach 2:
The solution moves from a single-diameter design to a multi-diameter design along the length of the passage. By varying the dimension in the axial direction, the passage can provide adequate cross-sectional area for gas flow at the inlet while reducing the cross-sectional area at sections exposed to strong electric fields
3Ease of manufacture
If traditional gas feed tubes are used, then manufacturing is simple, but component erosion occurs due to plasma exposure
Solution Approach 1:
The gas feed insert is provided as a separate replaceable component with segmented diameter sections, which can be manufactured using standard techniques and easily installed or replaced without affecting the main electrode structure
Solution Approach 2:
The gas feed insert is designed as a consumable component that can be easily replaced when worn. By making this protective component inexpensive and easily replaceable, the system maintains high reliability without requiring complex protective mechanisms
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 solution effectively confines plasma to the plasma generation region, reducing unwanted plasma formation and component erosion, while simplifying manufacturing and maintenance by allowing interchangeable inserts.
Implementation Method 1
an electric field is set up between grounded chamber components and the RF-energized upper electrode. This electric field may cause unwanted ignition of plasma from reactant gases in the gas feed passages
Data Source
AI summary
A gas feed insert configured to be disposed in a passage through an electrode assembly comprising a first insert end having therein a first bore aligned parallel with a linear axis of the gas feed insert. The gas feed insert further includes a second insert end opposite the first insert end, the second insert end having therein a second bore aligned parallel with the linear axis of the gas feed insert and a bore-to-bore communication channel in gas flow communication with the first bore and the second bore. The bore-to-bore communication channel is formed in an outer surface of the gas feed insert so as to prevent a line-of-sight when a gas flows from the first insert end through the bore-to-bore communication to the second insert end.