Capacitively Coupled Plasma Etching Apparatus with Adjustable Electrode Spacing
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Solution Overview
Problem
Capacitively coupled plasma etching apparatuses face instability in radio-frequency signals due to movement of the lower electrode, which complicates the adjustment of plate distances required for different etching steps.
Innovation Solution
A capacitively coupled plasma etching apparatus design that includes a retractable electrically conductive part connected to a radio frequency matcher, with a dielectric ring and inner conductive ring for shielding, allowing adjustable plate distances while maintaining radio-frequency loop stability through a retractable sealing part and electrically conductive strip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the lower electrode is moved to adjust plate distance, then the adaptability for different etching steps is improved, but the stability of the radio-frequency loop deteriorates
Solution Approach 1:
The lower electrode assembly is segmented into a fixed portion (lower electrode) and a movable portion (electrically conductive supporting rod with retractable electrically conductive part). This segmentation allows the plate distance to be adjusted by moving only the supporting rod while keeping the lower electrode fixed, thereby maintaining RF loop stability while achieving the adaptability needed for different etching steps.
Solution Approach 2:
The retractable electrically conductive part acts as an intermediary between the fixed lower electrode and the movable supporting rod. It provides continuous electrical connection during the retraction and extension movements, ensuring that the radio-frequency loop remains stable while allowing the plate distance to be adjusted. The intermediary component transfers the mechanical movement while maintaining electrical continuity.
2Reliability
If the lower electrode is fixed to maintain RF stability, then the reliability of the radio-frequency loop is improved, but the ability to adjust plate distance deteriorates
Solution Approach 1:
The system employs dynamic elements (retractable electrically conductive part and retractable sealing part) that allow the supporting rod to move vertically while maintaining electrical and sealing connections. This dynamic design enables the plate distance to be adjusted for different etching steps while the lower electrode remains fixed to ensure RF loop stability, thus resolving the contradiction between reliability and adaptability.
Solution Approach 2:
The adjustment mechanism operates in the vertical dimension (axial direction of the supporting rod) while the lower electrode remains fixed in position. By confining the movement to a specific dimension (vertical retraction and extension), the system achieves plate distance adjustability without compromising the horizontal stability of the RF loop connection.
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 distances without causing instability in the radio-frequency loop, ensuring stable plasma etching processes across various etching steps.
Implementation Method 1
a retractable electrically conductive part fixed to a lower end of the electrically conductive supporting rod, the retractable electrically conductive part being extended or retracted in the axial direction of the electrically conductive supporting rod
Implementation Method 2
the base further comprises a dielectric ring fixed to the outer side of the lower electrode, and an inner electrically conductive ring fixed to the outer side of the dielectric ring
Implementation Method 3
the inner electrically conductive ring is fixed to the bottom wall of the chamber body via a retractable sealing part, such that the upper surface of the lower electrode is disposed in an accommodation space where the chamber body is accommodated; and the retractable sealing part is extended or retracted in the axial direction of the electrically conductive supporting rod
Implementation Method 4
an electrically conductive strip is fixedly connected between the inner electrically conductive ring and the chamber body, the length of the electrically conductive strip being adapted to the movable amount of the retractable sealing part
Data Source
AI summary
Disclosed is a capacitively coupled plasma etching apparatus, wherein a lower electrode is fixed to a lower end of an electrically conductive supporting rod, a telescope electrically conductive part is fixed to the lower end of the electrically conductive supporting rod, wherein the retractable electrically conductive part being telescoped along an axial direction of the electrically conductive supporting rod; besides, the lower end of the retractable electrically conductive part is electrically connected with the output end of the radio-frequency matcher via an electrically connection portion. In this way, the height of the lower electrode may be controlled through telescoping of the retractable electrically conductive part, such that the spacing between the upper and lower pads becomes adjustable. Besides, an inner electrically conductive ring is further provided at the outer side of the lower electrode; the inner electrically conductive ring is electrically connected with the chamber body via the retractable electrically conductive part; shielding is formed between the inner electrically conductive ring, the lower electrode, and a radio frequency return path in the cavity, avoiding instability of the radio frequency loop caused by the lower electrode radio frequency field during the movement process, thereby achieving stability of the radio-frequency loop while achieving adjustability of the inter-pad spacing.