Capacitively Coupled Plasma Etching Apparatus with Adjustable Plate Distance
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Solution Overview
Problem
Conventional capacitively coupled plasma etching apparatuses have a fixed and non-adjustable plate distance between electrodes, which limits process flexibility and stability of the radio-frequency loop.
Innovation Solution
A capacitively coupled plasma etching apparatus with a retractable sealing part and an electrically conductive supporting rod connected to a driving means, allowing adjustable plate distance while maintaining radio-frequency loop stability through a hermetically sealed accommodation space and a radio frequency return path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the plate distance between electrodes is made adjustable to enhance process flexibility, then the adaptability of the apparatus is improved, but the stability of the radio-frequency loop deteriorates
Solution Approach 1:
The lower electrode assembly is segmented into a movable base portion (carrying the lower electrode) and a fixed chamber body portion. The base can be independently driven axially to adjust plate distance, while the chamber body remains stationary to maintain the radio-frequency loop stability. This segmentation allows the movable base to adjust electrode spacing without causing chamber body displacement that would disrupt the RF loop.
Solution Approach 2:
A retractable sealing part (bellows seal) acts as an intermediary component connecting the movable base to the fixed chamber body. This sealing part allows axial movement of the base while maintaining hermetic sealing of the vacuum chamber, enabling plate distance adjustment without compromising chamber integrity or RF loop stability.
2Adaptability or versatility
If the chamber body is made movable to adjust plate distance, then the adjustability is improved, but the structural complexity and difficulty of maintaining vacuum sealing increase
Solution Approach 1:
Instead of making the chamber body movable to adjust plate distance, the invention inverts the approach by making the lower electrode base movable while keeping the chamber body fixed. This inversion simplifies the vacuum sealing structure, as only the base needs to be sealed (using a retractable sealing part) rather than sealing the entire movable chamber body.
3Reliability
If electrodes are fixed to maintain radio-frequency loop stability, then the stability is improved, but the adjustability of plate distance deteriorates
Solution Approach 1:
The lower electrode base is designed with dynamic movability through axial driving, allowing it to change position for plate distance adjustment. Meanwhile, the chamber body remains static to maintain RF loop stability. This dynamic design of the base portion enables flexibility in plate spacing while the fixed chamber body preserves radio-frequency loop stability.
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 adjustable plate distance between electrodes while maintaining radio-frequency loop stability, enhancing the flexibility and efficiency of plasma etching processes.
Implementation Method 1
the base being fixed to the bottom wall of the chamber body via a retractable sealing part, causing the upper surface of the lower electrode to be hermetically sealed in an accommodation space where the chamber body is accommodated
Implementation Method 2
driving means fixed to a lower end of the electrically conductive support rod, the driving means driving the electrically conductive supporting rod to move axially
Implementation Method 3
an electrical connection part connected to the chamber body, radio frequency current in the chamber body returning, via the electrical connection part, to the loop end
Data Source
AI summary
Disclosed is a capacitively coupled plasma etching apparatus, wherein an electrically conductive supporting rod where a lower electrode is fixed is connected to driving means, the driving means driving the electrically conductive support rod to move axially; besides, the lower electrode is fixed to the bottom of a chamber body via a retractable sealing part, causing the upper surface of the lower electrode to be hermetically sealed in an accommodation space in the chamber body; an electrical connection part is connected on the chamber body; the radio frequency current in the chamber body returns, via the electrical connection part, to the loop end of a radio frequency matcher. In this way, the lower electrode is fixed on the chamber body via the retractable sealing part, such that when the lower electrode is driven by the driving means to move up/down, the chamber body does not move along with it, and the radio frequency loop in the chamber body is in a steady state, thereby achieving stability of the radio frequency loop while implementing adjustability of the plate distance.