Plasma Processing Apparatus Faraday Shield Design
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Solution Overview
Problem
In plasma processing apparatuses, the induction coil inside the reaction chamber is prone to sputtering due to high RF bias, leading to contamination and reduced target utilization efficiency, necessitating the use of the same material for the coil and target, which limits material flexibility and increases costs.
Innovation Solution
A plasma processing apparatus design featuring a Faraday shield component with a low RF bias, positioned outside the reaction chamber, and an induction coil system comprising an insulating sub-chamber and a conductive sub-chamber, which reduces RF bias and prevents particle deposition on the Faraday shield, thereby minimizing contamination and enhancing target utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the induction coil is placed inside the reaction chamber to enhance plasma density, then the deposition coverage is improved, but the coil is sputtered by plasma causing particle contamination and reduced target utilization efficiency
Solution Approach 1:
The induction coil is extracted from inside the reaction chamber and placed outside, eliminating the direct exposure to plasma that causes sputtering and particle contamination. This allows the coil to continue generating RF power for plasma enhancement without suffering from the harmful effects of being inside the chamber.
Solution Approach 2:
A Faraday shield component is introduced as an intermediary between the induction coil and the plasma environment. The shield, made of conductive material with high RF bias, absorbs the plasma's harmful effects while allowing the coil to function. The shield acts as a protective barrier that prevents sputtering of the coil and subsequent particle contamination.
2Object-generated harmful factors
If the coil and target are made of the same material to prevent sputtering, then particle contamination is reduced, but material selection flexibility is limited and apparatus cost increases
Solution Approach 1:
The Faraday shield component serves as an intermediary that protects the induction coil from plasma sputtering. This allows the coil to be made from materials optimized for RF performance rather than requiring the same material as the target, thus restoring material selection flexibility while preventing particle contamination.
3Productivity
If particles accumulate on the coil surface, then the target utilization efficiency is reduced, but removing particles requires additional maintenance time
Solution Approach 1:
By extracting the induction coil from the reaction chamber and placing it outside, particles cannot accumulate on the coil surface during operation. This eliminates the need for maintenance time dedicated to particle removal and maintains constant target utilization efficiency.
Solution Approach 2:
The Faraday shield component acts as a sacrificial element that prevents particles from reaching and accumulating on the induction coil. The shield absorbs the particle-generating sputtering effects, keeping the coil clean and maintaining target utilization efficiency without requiring maintenance intervention.
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
The solution effectively prevents wafer contamination and extends the apparatus' working life while reducing costs by maintaining a low RF bias and improving target material efficiency.
Implementation Method 1
The coil 7 applies the RF power of the first RF power supply 41 into the reaction chamber, so as to further increase the plasma density
Implementation Method 2
A Faraday shield component is provided inside the insulating sub-chamber, the Faraday shield component is made of metal material, or of insulating material electroplated with conductive coatings
Implementation Method 3
The direct current power supply 6 applies direct-current power to the target 3 to generate plasma and attract ions in the plasma to bombard the target 3 so that after being sputtered
Implementation Method 4
bombard the target with plasma generated by the direct current power supply so that the material of the target is deposited on the wafer to be processed so as to form a film
Implementation Method 5
In addition, a magnetron is arranged above the target to increase sputtering efficiency
Implementation Method 6
The RF power applied to the electrostatic chuck 8 can generate RF self-bias to attract ions, so that the effect of pore-filling can be improved
Data Source
AI summary
A plasma processing apparatus includes a chamber (20) and a target (25) above the chamber (20). The surface of the target (25) contacts the processing area of the chamber (20). The chamber (20) includes an insulating sub-chamber (21) and a first conductive sub-chamber (22), which are superposed. The first conductive sub-chamber (22) is provided under the insulating sub-chamber (21). The insulating sub-chamber (21) is made of insulating material, and the first conductive sub-chamber (22) is made of metal material. A Faraday shield component (10) which is made of metal material or insulating material electroplated with conductive coatings and includes at least one slit is provided in the insulating sub-chamber (21). An inductance coil (13) surrounds the exterior of the insulating sub-chamber (21). The problem about the wafer contamination due to particles formed on the surface of the coil during the sputtering process can be solved by using the plasma processing apparatus.