Segmented Substrate Carrier Electrodes for Spillover Plasma Control
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Solution Overview
Problem
In vacuum processing systems, the large geometry of substrate carriers relative to plasma sources leads to an unfavorable area ratio, resulting in reduced substrate processing efficiency, increased formation of undesired spillover plasma, and high reactive currents, which complicates the injection of RF voltage and reduces energetic efficiency.
Innovation Solution
A substrate carrier device with a segmented design, where RF voltage is selectively coupled only to areas interacting with the plasma source, featuring a plurality of galvanically separated electrodes to optimize the active area to counter-electrode ratio, typically between 1:2 to 1:4, inhibiting spillover plasma and enhancing self-bias voltage formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large substrate carrier is used to accommodate substrates, then substrate processing capacity is improved, but the area ratio between carrier and plasma source becomes unfavorable, reducing processing efficiency
Solution Approach 1:
The substrate carrier is divided into multiple galvanically separated electrode segments along the direction of movement. This segmentation allows different regions of the carrier to be independently controlled, enabling selective RF voltage application only to areas interacting with the plasma source, thus optimizing the active area to counter-electrode ratio while maintaining large carrier geometry for high substrate capacity
Solution Approach 2:
Different regions of the substrate carrier are assigned different electrical properties through galvanic separation. The active area segments are equipped with RF voltage coupling capabilities while other segments remain electrically isolated or grounded, creating local quality differences that optimize plasma interaction zones without compromising overall carrier functionality
2Strength
If RF voltage is applied to the entire substrate carrier, then self-bias voltage formation is enhanced, but reactive currents increase and spillover plasma is formed
Solution Approach 1:
The carrier electrode is segmented into multiple galvanically isolated sections, allowing RF voltage to be applied selectively only to the active area segments that interact with the plasma source. This prevents voltage propagation to non-active regions, thereby reducing spillover plasma formation and reactive currents while maintaining sufficient self-bias voltage in the active zones
Solution Approach 2:
The harmful effects of spillover plasma and excessive reactive currents are eliminated by extracting the RF voltage application from the entire carrier structure and restricting it only to the necessary active area segments, thereby removing the source of these harmful phenomena while preserving the beneficial self-bias voltage effect
3Ease of operation
If RF voltage is coupled to the large substrate carrier, then plasma processing is enabled, but technical effort and complexity for RF coupling increases
Solution Approach 1:
The RF coupling system is simplified by segmenting the carrier into electrically isolated electrode sections. This allows RF voltage to be coupled only to the minimal necessary active area segments rather than the entire large carrier structure, significantly reducing the complexity of RF coupling hardware and control systems while maintaining full plasma processing capability
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
This configuration improves substrate processing by amplifying the self-bias voltage, reducing reactive currents, and increasing the energetic efficiency of the plasma source, while minimizing technical efforts for RF coupling and preventing parasitic plasma formation.
Implementation Method 1
substrates may be processed in a vacuum by means of a plasma (also referred to as plasma-assisted processing)... The plasma may be formed by ionizing a plasma-forming gas
Implementation Method 2
A commonly used configuration of plasma-assisted processing is known as plasma-enhanced chemical vapor deposition (plasma-enhanced CVD or PECVD)
Implementation Method 3
a high-frequency voltage is conventionally applied to a metallic, isolated, substrate-carrying substrate carrier (also referred to as a carrier) to produce a so-called self-bias voltage (also referred to as a self-bias voltage)... to amplify the electric field that causes acceleration of ions from a plasma onto an electrically insulated substrate
Data Source
AI summary
Disclosed herein are devices, systems, and methods for transporting a substrate for vacuum processing. The transport may be provided by a substrate carrying device that includes a support area by which a substrate carrier may be moveably supported. The substrate carrying device includes a plurality of electrodes that are galvanically separated from one another. The substrate carrying device includes a plurality of substrate carrying regions arranged consecutively in series with respect to one another, each substrate carrying region including an electrode of the plurality of electrodes and also including a substrate receiving device configured to receive a substrate placed in the substrate carrying region, preferably in physical contact with the electrode.