Vertical DC Ground Member for Plasma Uniformity
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Solution Overview
Problem
In plasma processing apparatuses, the uniformity of processes in the circumferential direction is degraded due to the installation state of the conductive ring-shaped ground member for the DC voltage, requiring time-consuming adjustments to correct processing biases, thereby affecting productivity.
Innovation Solution
A plasma processing apparatus with a ground member for DC voltage having an overall ring shape, formed of conductive material, exposed to the processing space, and equipped with vertical movement mechanisms to adjust the grounding state, allowing for easy correction of biased states without opening the processing chamber to the atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive ring-shaped ground member is provided to surround the holding stage, then a ground potential can be formed for the DC voltage applied to the upper electrode, but the uniformity of process in the circumferential direction of the substrate is degraded due to installation state variations
Solution Approach 1:
The ground member is made movable in the vertical direction through a movement mechanism, allowing its position to be adjusted dynamically. This enables optimization of the grounding state to achieve uniform process conditions across the substrate, resolving the contradiction between maintaining stable grounding and ensuring process uniformity.
2Reliability
If the conductive ring-shaped ground member is installed to provide ground potential, then DC voltage grounding is achieved, but correction of processing bias requires opening the processing chamber to the atmosphere, resulting in time-consuming adjustments
Solution Approach 1:
The ground member's vertical movement capability allows for in-situ adjustment of the grounding state without requiring chamber opening. The movement mechanism enables rapid correction of processing biases during operation, significantly improving adjustment efficiency and productivity while maintaining reliable grounding.
Solution Approach 2:
The manual mechanical adjustment process requiring chamber opening is replaced with an automated vertical movement mechanism that can adjust the ground member position remotely. This substitution eliminates the need to open the processing chamber for adjustments, thereby maintaining productivity and reliability.
3Ease of manufacture
If the ground member is fixed in position, then installation is simple, but the grounding state cannot be adjusted to correct processing biases
Solution Approach 1:
The ground member is designed with vertical movement capability through a movement mechanism, transforming it from a fixed to a movable component. This allows the system to maintain simple installation procedures while gaining the adaptability to adjust the grounding state for correcting processing biases, thus resolving the contradiction between ease of manufacture and adaptability.
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
Enables uniform and efficient plasma processing by allowing rapid adjustment of the grounding state of the ground member, improving processing efficiency and reducing instrument errors, particularly in large-sized wafers.
Implementation Method 1
a plasma processing apparatus which performs various processes, for example, an etching process or a film forming process, by applying plasma onto a substrate
Implementation Method 2
a first RF power having a relatively high frequency for generating plasma
Implementation Method 3
a second RF power having a frequency lower than that of the first RF power for implanting ions
Data Source
AI summary
A plasma processing apparatus includes: a radio frequency (RF) power source which applies an RF power to a lower electrode; a direct current (DC) power source which applies a DC voltage to an upper electrode; a ground member for the DC voltage that is a ring shape formed of a conductive material, that is arranged in the processing chamber such that at least a part of the ground member is exposed to the processing space, and that forms a ground potential with respect to the DC voltage applied to the upper electrode; and a plurality of vertical movement mechanisms which move the ground member for the DC voltage in a vertical direction to adjust a grounding state of the ground member for the DC voltage.