Substrate Support Lifter Pin Threaded Interface Abnormal Discharge
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Solution Overview
Problem
Abnormal discharge occurs in substrate processing apparatuses during plasma etching due to high radio-frequency power, leading to deteriorated target object quality and reduced yield.
Innovation Solution
A substrate support with pin through-holes featuring a female-threaded inner wall and male-threaded lifter pins, where the lifter pins are screwable and vertically movable, reducing the path length for electron acceleration and preventing electron avalanches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high radio-frequency power is applied to the substrate support for plasma etching, then the etching process can be performed, but abnormal discharge occurs in the through-holes where lifter pins are inserted
Solution Approach 1:
The patent applies local quality by modifying the through-hole structure specifically at the location where abnormal discharge occurs. The through-hole is designed with a tapered shape (wider at the top, narrower at the bottom) and includes a protrusion that extends into the hole. These localized structural modifications create regions with different electrical properties, preventing electron avalanche and abnormal discharge at the critical interface between the lifter pin and substrate support, while allowing high radio-frequency power to be applied elsewhere for effective plasma etching.
2Device complexity
If conventional through-holes are used in the substrate support, then the structure is simple, but abnormal discharge deteriorates target object quality and decreases yield
Solution Approach 1:
The patent introduces localized structural features (tapered shape and protrusion) within the through-hole to prevent abnormal discharge. These features are confined to specific regions of the through-hole, minimizing the overall complexity increase while effectively addressing the discharge problem. The protrusion and tapered geometry create electrical field distribution that prevents electron avalanche, thereby protecting target object quality without requiring complete redesign of the substrate support structure.
Solution Approach 2:
The protrusion structure acts as an intermediary element between the lifter pin and the through-hole wall. It modifies the electrical field distribution and physical interface in a controlled manner, preventing direct contact and abnormal discharge between the lifter pin and the substrate support body. This intermediary structure effectively mediates the interaction between moving and stationary components, preventing harmful effects while maintaining functional requirements.
3Length of moving object
If the through-hole path is long, then the lifter pin can be fully inserted, but electron acceleration path increases leading to electron avalanche and abnormal discharge
Solution Approach 1:
The patent applies local quality by creating a tapered through-hole geometry where the diameter varies along the insertion path. The hole is wider at the top and narrower at the bottom, with a protrusion extending into the hole. This localized geometric modification reduces the effective electron acceleration path length in the critical lower region where the lifter pin contacts the substrate support, preventing electron avalanche while still allowing sufficient insertion depth for proper lifter pin function.
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 suppresses abnormal discharge, improving the quality of the target object and increasing the yield of the plasma processing by extending the minimum discharge voltage, thus preventing damage to the wafer and enhancing processing efficiency.
Implementation Method 1
a lifter pin having a base segment, an intermediate segment, and a leading segment, the lifter pin being inserted into the pin through-hole, the intermediate segment being male-threaded, the male-threaded intermediate segment being screwable to the female-threaded inner wall
Data Source
AI summary
A substrate support for use in a plasma processing chamber includes a substrate support body, a lifter pin and a lift mechanism. The substrate support body has a pin through-hole and the pin through-hole has a female-threaded inner wall. The lifter pin has a base segment, an intermediate segment, and a leading segment. The lifter pin is inserted into the pin through-hole, the intermediate segment is male-threaded, and the male-threaded intermediate segment is screwable to the female-threaded inner wall. The lift mechanism is configured to vertically move the lifter pin relative to the substrate support body.