Resistive Edge Ring Layout for Uniform Plasma Sheath Control
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Solution Overview
Problem
The miniaturization and high integration of semiconductor products lead to non-uniform dry etching processes, affecting the characteristics of semiconductor devices due to perturbations in the plasma sheath formed above the edge ring in plasma processing apparatuses.
Innovation Solution
A plasma processing apparatus is designed with an edge ring, a dielectric ring, and an electrode ring of specific resistivity values, where the electrode ring with a higher resistivity value is positioned below the edge ring to minimize perturbation and expand the control range of the plasma sheath, using RF power supplies to control the electric field and plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the plasma sheath is controlled through the edge ring in conventional plasma processing apparatus, then the plasma processing can be performed, but the control range of the plasma sheath is limited and perturbation of plasma occurs
Solution Approach 1:
A dielectric ring is introduced as an intermediary component between the lower electrode and the edge ring. The dielectric ring has a lower resistivity value than the edge ring, allowing it to act as a mediator that distributes electrical potential more effectively. This intermediary structure expands the control range of the plasma sheath while reducing direct perturbation from the edge ring, thereby improving plasma uniformity without limiting adaptability
Solution Approach 2:
The patent applies local quality by creating a resistivity gradient across different components: the edge ring has high resistivity to minimize plasma perturbation, while the dielectric ring has lower resistivity to expand control range. This localized differentiation of electrical properties allows each component to perform its specific function optimally, resolving the contradiction between control range and plasma stability
2Ease of operation
If the plasma sheath is controlled through the edge ring, then plasma processing is enabled, but perturbation of plasma increases affecting etching uniformity
Solution Approach 1:
The dielectric ring serves as a mediator that decouples the direct connection between the power supply and the edge ring. By introducing this intermediate layer with controlled resistivity, the system maintains ease of plasma sheath control while the edge ring's high resistivity minimizes its perturbing effect on the plasma, thereby improving etching uniformity
Solution Approach 2:
The patent changes the electrical resistance parameter of the components in the plasma processing apparatus. By selecting specific resistivity values for the edge ring (higher) and dielectric ring (lower), the system optimizes the balance between control capability and plasma stability, reducing perturbation while maintaining operational ease
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 enhances the uniformity of plasma processing by reducing power consumption and perturbation, thereby increasing the control range of the plasma sheath and improving etching rate consistency across the semiconductor wafer.
Implementation Method 1
forming plasma in the processing chamber by applying first power supply and second power supply to the upper electrode and the lower electrode, respectively
Implementation Method 2
a dielectric ring supporting a lower portion of the edge ring, formed of a material having a second resistivity value lower than that of the first resistivity value, and connected to a third power supply, and controlling a potential of a plasma sheath formed above the edge ring by applying third power supply to the dielectric ring
Data Source
AI summary
A plasma processing apparatus includes: an electrostatic chuck supporting a wafer, and connected to a first power supply, an edge ring disposed to surround an edge of the electrostatic chuck and formed of a material having a first resistivity value, a dielectric ring supporting a lower portion of the edge ring, formed of a material having a second resistivity value lower than that of the first resistivity value, and connected to a second power supply, and an electrode ring disposed in a region overlapping the dielectric ring, in contact with a lower surface of the edge ring, and formed of a material having a third resistivity value greater than the first resistivity value, wherein the third resistivity value is a value of 90 Ωcm to 1000 Ωcm.