Closed-Loop LC Plasma Resonator for Uniform High-Rate Etching
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Solution Overview
Problem
Conventional inductively coupled plasma (ICP) resonator sources face challenges in achieving low skew, high etching rate, and uniform power deposition, often requiring a Faraday shield that hampers plasma striking and overall performance, making them unsuitable for advanced semiconductor manufacturing.
Innovation Solution
A closed-loop series inductor/capacitor (LC) coil network with a flower shape is used, generating a resonant electrical current to induce and sustain plasma, eliminating the need for a Faraday shield and enabling high etching rate with uniform plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional single coil ICP resonator source is used, then the structure is simple, but plasma uniformity deteriorates with m-shape skew
Solution Approach 1:
The single coil structure is segmented into multiple discrete coils arranged in a specific geometric pattern (e.g., pentagon, hexagon, or other closed-loop configurations). Each coil can be independently controlled, allowing precise manipulation of plasma density distribution to eliminate m-shape skew and achieve uniform plasma across the substrate surface.
Solution Approach 2:
The coils are arranged in asymmetric geometric patterns (such as pentagonal or hexagonal configurations) rather than traditional symmetric circular arrangements. This asymmetric layout, combined with specific current ratios and phase differences between coils, enables cancellation of m-shape skew and achievement of uniform plasma distribution.
2Manufacturing precision
If two ICP coils are used to reduce skew, then plasma uniformity is improved, but Faraday shield becomes necessary which harms plasma striking and etching rate
Solution Approach 1:
The Faraday shield component is extracted and removed from the system entirely. The invention achieves the previously unattainable combination of high coil voltage capability and direct plasma generation by using a closed-loop coil configuration that inherently handles voltage distribution without requiring the shield, thereby eliminating its detrimental effects on plasma striking and etching rate.
Solution Approach 2:
Instead of using a Faraday shield to manage high voltage (conventional approach), the invention inverts the approach by designing a closed-loop coil system that directly tolerates and utilizes high coil voltages without the shield. This reversal eliminates the shield's harmful effects while maintaining plasma uniformity through the closed-loop geometry and coordinated coil control.
3Ease of manufacture
If conventional ICP coils are used, then the design is straightforward, but operation window and plasma control performance are insufficient for advanced semiconductor manufacturing
Solution Approach 1:
The system implements dynamic control of multiple coils with independently adjustable current ratios and phase differences. This dynamic capability allows real-time optimization of plasma characteristics across a wide operation window, enabling adaptation to various advanced semiconductor manufacturing processes while maintaining a relatively simple closed-loop coil structure.
Solution Approach 2:
The closed-loop coil configuration serves multiple functions simultaneously: it generates plasma uniformly, handles high coil voltages without Faraday shield, enables wide operation windows through phase and amplitude control, and provides flexible plasma density distribution. This multi-functionality makes the design suitable for diverse advanced semiconductor manufacturing applications.
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 provides improved plasma uniformity and etching rate without a Faraday shield, simplifying frequency control and enhancing semiconductor manufacturing capabilities.
Implementation Method 1
By feeding a radio frequency (RF) current to an ICP resonator source, the ICP resonator source emits an electromagnetic (EM) wave that ignites and sustains plasma in the RIE chamber body, e.g., via inductive coupling
Implementation Method 2
having a resonant frequency defined by a total inductance and a capacitance of the plurality of LC sections such that when RF power is applied to the closed-loop series inductor/capacitor (LC) coil network a resonant electrical current is generated
Data Source
AI summary
An apparatus for generating plasma inductively in a process chamber is provided herein and comprises a closed-loop series inductor/capacitor (LC) coil network comprising a plurality of LC sections and having a resonant frequency defined by a total inductance and a capacitance of the plurality of LC sections such that when RF power is applied to the closed-loop series inductor/capacitor (LC) coil network a resonant electrical current is generated in the closed-loop series inductor/capacitor (LC) coil network to inductively generate and sustain plasma in the process chamber.