Grounded Anode Aperture Shield for Stable Thin-Film Deposition
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Solution Overview
Problem
In plasma enhanced deposition processes, the accumulation of insulating species on chamber components leads to instability and poor film quality due to arcing and reduced deposition rates, as the anode becomes coated and loses its conductive ground path, affecting the uniformity and quality of thin-film deposition.
Innovation Solution
The implementation of a chamber structure with shielding to limit the deposition angles and energies of species, and an anode design with a magnetic filter bar to deflect electrons and prevent coating, maintaining a conductive ground path and reducing Joule heating, while using a magnet with a high magnetic mirror ratio to filter electrons and maintain process stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional anode is used in the plasma chamber, then the plasma process can be maintained, but insulating species accumulate on the anode surface causing plasma instability and arcing
Solution Approach 1:
The anode is segmented into multiple functional zones: a plasma-facing surface that accepts insulating species, an insulated intermediate section, and a conductive ground connection section. This segmentation allows the anode to maintain electrical connectivity while isolating the plasma instability effects to specific regions, preventing complete plasma chamber instability.
Solution Approach 2:
An intermediate insulating section is introduced between the plasma-facing anode surface and the ground connection. This intermediary layer acts as a buffer that prevents insulating species from reaching the ground path, maintaining electrical conductivity while allowing the plasma process to continue.
2Manufacturing precision
If reactive gases are introduced to adjust film stoichiometry, then desired oxidation state and film quality are achieved, but excessive electrons are produced causing plasma damage and heating
Solution Approach 1:
The anode structure is designed to extract and collect excessive electrons generated during reactive gas processing. By providing a dedicated electron collection path through the segmented anode structure, the harmful electron flux is removed from the plasma, preventing substrate damage and excessive heating while maintaining the beneficial stoichiometry control.
3Duration of action of stationary object
If the anode is coated with insulating material, then the chamber can continue operating, but the anode loses its conductive ground path and plasma becomes unstable
Solution Approach 1:
The anode is divided into segments where only specific portions are exposed to plasma deposition. The ground connection section remains shielded from insulating species, maintaining conductivity throughout extended operation periods.
Solution Approach 2:
An insulating barrier section is positioned between the plasma-facing surface and the ground connection, acting as a mediator that allows continuous operation by preventing insulation from compromising the ground path.
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 solution enhances film uniformity and deposition rate by preventing insulative coating on the anode, maintaining plasma stability, and ensuring consistent film properties across the substrate, thereby improving the overall quality and reliability of the thin-film deposition process.
Implementation Method 1
a magnet positioned within the anode block and generating magnetic field lines extending outwardly from the front surface of the anode block
Implementation Method 2
using a magnet with a high magnetic mirror ratio to filter electrons and maintain process stability
Implementation Method 3
Traditional plasma physical vapor deposition (PVD) chambers decompose precursor gases to thereby ignite and maintain plasma and accelerate particles from the plasma towards a target
Implementation Method 4
physical vapor deposition. High throughput of multiple layer thin film stacks from a few nanometers up to several microns thick can be achieved by employing magnetron cathodes
Data Source
AI summary
A plasma chamber for physical vapor deposition, having an anode aperture shield that reduces the field of view to the substrate for deposition particles from the sputtering target. The anode aperture shield limits the deposition particles reaching the substrate to selected maximum angles from the vertical, and rejects particles approaching with a larger angle from the vertical. The node aperture shield is grounded and may be constructed of an upper plate and a lower plate spaced apart from the upper plate, wherein the upper plate may include perforations or may incorporate an electron filter.