Plasma Processing Apparatus Edge Field Control
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Solution Overview
Problem
The existing plasma processing apparatuses face challenges in controlling the electric field near the outer peripheral edge of a wafer due to power leakage between circuits, leading to inhomogeneous etching and reduced yield, especially with unstable matching devices and high impedance dielectric ring covers.
Innovation Solution
A plasma processing apparatus with a configuration that includes a base material electrode, a ring-shaped conductive electrode, a dielectric ring cover, and an impedance adjustable circuit, where the power supply path to the ring-shaped electrode is connected via a resistive element, allowing independent control of high frequency power to the conductive ring and base material, stabilizing the electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high frequency power is supplied to both the base material electrode and ring-shaped electrode independently, then the electric field distribution can be controlled more uniformly, but power leakage between circuits occurs causing unstable matching device operation
Solution Approach 1:
The power supply system is divided into two independent high frequency power supply circuits: one for the base material electrode and another for the ring-shaped electrode. This segmentation allows independent control of power to each electrode, enabling uniform electric field distribution while preventing power leakage interference between circuits.
Solution Approach 2:
A matching device is introduced as an intermediary component between the high frequency power supply and the ring-shaped electrode. This matching device stabilizes the power transmission by matching impedance, preventing power leakage from affecting the stability of the system while maintaining independent control capability.
2Reliability
If a dielectric ring cover is used to cover the ring-shaped electrode, then the electric field is stabilized, but the high impedance of the dielectric cover causes power leakage and unstable matching
Solution Approach 1:
The dielectric ring cover acts as an intermediary component between the ring-shaped electrode and the plasma environment. It provides electric field stabilization and insulation while the matching device compensates for the high impedance effect, preventing power leakage and ensuring stable operation.
Solution Approach 2:
The system adjusts the impedance parameters of the power supply circuit through the matching device to compensate for the high impedance characteristic of the dielectric ring cover. By changing the electrical parameters dynamically, power leakage is minimized while maintaining the stabilizing effect of the dielectric cover.
3Ease of operation
If the ring-shaped electrode is disposed outside the dielectric ring cover, then the electrode can be accessed easily, but the electric field near the wafer edge becomes inhomogeneous
Solution Approach 1:
The ring-shaped electrode is nested inside the dielectric ring cover, with the electrode positioned within the cover structure. This nested configuration allows the electrode to be easily accessed and replaced while the dielectric cover maintains a uniform gap between the electrode and wafer edge, ensuring homogeneous electric field distribution and consistent etching quality.
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 prevents inhomogeneity of the electric field near the wafer's edge, reduces processing variations in the in-plane direction, and improves processing yield across various plasma conditions by ensuring stable impedance matching and reduced voltage drops.
Implementation Method 1
a bias potential generated by high frequency power formed on an upper surface of a sample
Implementation Method 2
attracts a charged particle such as an ion in plasma... to a sample surface by a bias potential
Implementation Method 3
processing of forming a circuit structure by etching a film structure... using plasma formed in the processing chamber
Implementation Method 4
exciting, ionizing and diverging gas that is used for processing and is introduced into a processing chamber
Data Source
AI summary
Provided is a technique capable of reducing a variation in processing in an in-plane direction of a sample and improving a yield of processing. A plasma processing apparatus 1 includes a first electrode (a base material 110B) disposed in a sample stage 110, a ring-shaped second electrode (a conductive ring 114) disposed surrounding an outer peripheral side of an upper surface portion 310 (a dielectric film portion 110A) of the sample stage 110, a dielectric ring-shaped member (a susceptor ring 113) that covers the second electrode and is disposed surrounding an outer periphery of the upper surface portion 310, a plurality of power supply paths that supply high frequency power from a high frequency power supply to the first electrode and the second electrode respectively, and a matching device 117 disposed on a power supply path to the second electrode. Further, a first position (A1) and a grounding position between the second electrode and the matching device 117 on the power supply path to the second electrode are electrically connected via a resistor 118 having a predetermined value.