Dual Plasma Source Chamber for Ion-to-Radical Ratio Control
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Solution Overview
Problem
Current semiconductor fabrication processes using plasma for deposition and etching lack effective control over the ratio of ions to radicals in plasma, affecting the precision and efficiency of processes like etching and deposition.
Innovation Solution
A plasma processing system with a chamber design that includes an upper and lower housing, where electron beam sources generate an upper plasma and RF-powered cathode holes produce a lower plasma, allowing for controlled ratios of radicals and ions to be directed to a wafer, with the confinement electrode guiding electron beams and magnetic coils managing plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single plasma source is used for deposition and etching, then the device structure is simple, but the control over ion-to-radical ratio is insufficient
Solution Approach 1:
The plasma source is divided into two separate sources: a first plasma source that generates radicals and a second plasma source that generates ions. This segmentation allows independent control of radical and ion fluxes, enabling precise adjustment of the ion-to-radical ratio without requiring complex control mechanisms in a single plasma source.
Solution Approach 2:
A guide electrode is introduced as an intermediary component between the two plasma sources and the substrate. This electrode selectively guides ions and radicals from the respective plasma sources to the substrate, providing mechanical control over the ion-to-radical ratio while keeping the overall device structure relatively simple.
2Productivity
If electron beams are used to generate plasma, then deposition and etching can be performed, but the directionality of ions is insufficient
Solution Approach 1:
The guide electrode acts as a mediator that selectively directs ions from the second plasma source toward the substrate with improved directionality. By positioning and biasing the guide electrode appropriately, ions are channeled along desired trajectories while radicals from the first plasma source continue to provide isotropic coverage for deposition.
Solution Approach 2:
The system creates different plasma conditions in different regions: the first plasma source provides a radical-rich environment for isotropic deposition, while the second plasma source with the guide electrode creates an ion-directed flux for anisotropic etching. This local differentiation of plasma properties enables both deposition and etching with appropriate directionality.
3Adaptability or versatility
If radicals and ions are provided to the substrate, then both deposition and etching are enabled, but the ratio control is difficult
Solution Approach 1:
By separating the plasma generation into two independent sources, each optimized for producing either radicals or ions, the system enables versatile deposition and etching processes while keeping the control mechanism relatively simple. The independence of the two sources allows easy adjustment of the ion-to-radical ratio by controlling individual source parameters without complex interdependent controls.
Solution Approach 2:
The guide electrode serves as a simple yet effective intermediary that provides mechanical control over ion delivery to the substrate. By adjusting the position and bias of this single component, the system can control the ion-to-radical ratio and switch between deposition and etching modes without requiring complex control mechanisms.
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 system enables precise control over the ion-to-radical ratio in the reaction plasma, enhancing the directionality and efficiency of etching processes and deposition rates, improving semiconductor device fabrication outcomes.
Implementation Method 1
electron beam sources providing electron beams into the upper housing to generate an upper plasma
Implementation Method 2
an RF power generating a source plasma from the source gas in the hollow inside of the source housing
Implementation Method 3
a source electrode having an aperture, the source electrode being configured to cause to extract, through the opening of the source housing, the plurality of electrons from the source plasma of the source housing and accelerate the plurality of electrons extracted from the source plasma
Data Source
AI summary
A chamber has an upper housing and a lower housing and receives a reaction gas. A first plasma source includes electron beam sources providing electron beams into the upper housing to generate an upper plasma. A second plasma source includes holes generating a lower plasma within the holes connecting the upper housing and the lower housing. Radicals of the upper plasma, radicals of the lower plasma, and ions of the lower plasma are provided, through the holes, to the lower housing so that the lower housing has radicals and ions at a predetermined ratio of the ions to the radicals in concentration. The second plasma source divides the chamber into the upper housing and the lower housing. A wafer chuck is positioned in the lower housing to receive a wafer.