Multi-Material Dielectric Window for Uniform ICP Plasma Coupling
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Solution Overview
Problem
Existing inductively coupled plasma (ICP) process chambers face challenges in achieving uniform plasma distribution due to limitations in dielectric window designs, which can lead to radial non-uniformity and material accumulation issues, affecting processing yield and component compatibility.
Innovation Solution
A dielectric window with multiple materials having different dielectric constants is used, allowing for varying RF coupling efficiency across the window without altering its shape or the RF coil design, thereby improving plasma uniformity by creating distinct radial sections for power coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the shape of the dielectric window is varied along the plasma-facing side to change thickness, then RF coupling efficiency is improved, but material accumulation occurs around protrusions and gas flow is interfered with
Solution Approach 1:
The patent applies local quality by varying the dielectric constant in different radial sections of the dielectric window while maintaining a uniform thickness profile. The dielectric window includes a central section with a first dielectric constant and an annular section with a second dielectric constant, allowing localized optimization of RF coupling without creating protrusions that would cause material accumulation.
Solution Approach 2:
The patent changes the dielectric constant parameter across different radial sections of the dielectric window to optimize RF coupling efficiency. By adjusting the dielectric constant rather than the physical thickness, the invention achieves variable coupling efficiency without geometric variations that would lead to harmful protrusions.
2Reliability
If the dielectric window thickness is varied to improve plasma uniformity, then RF coupling efficiency is improved, but the window geometry becomes complex and interferes with other components
Solution Approach 1:
The patent implements local quality by assigning different dielectric constants to different radial sections of the dielectric window. This allows the window to maintain a simple, uniform thickness geometry while achieving localized optimization of plasma uniformity through material property variations rather than geometric complexity.
Solution Approach 2:
The patent uses composite materials with different dielectric constants in different sections of the dielectric window. The window comprises a central section with one dielectric material and an annular section with another dielectric material, creating a composite structure that achieves plasma uniformity without geometric complexity.
3Ease of manufacture
If a single dielectric material is used in the dielectric window, then manufacturing is simplified, but RF coupling efficiency cannot be optimized across different radial sections
Solution Approach 1:
The patent employs composite materials by combining two different dielectric materials in a single window structure. The central section uses a first dielectric material while the annular section uses a second dielectric material with a different dielectric constant, enabling optimized RF coupling efficiency across different radial sections while maintaining a relatively simple manufacturing process.
Solution Approach 2:
The patent applies segmentation by dividing the dielectric window into distinct radial sections with different materials. The window is segmented into a central section and an annular section, each with optimized dielectric properties for their specific functional requirements, allowing tailored RF coupling optimization.
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 plasma uniformity and process yield by adjusting the local dielectric constant through the use of materials with different dielectric properties, reducing radial non-uniformity and maintaining a consistent window thickness, thus optimizing RF coupling efficiency without changing the chamber geometry.
Implementation Method 1
a dielectric window having multiple materials, wherein such materials can have different dielectric constants, thereby varying the RF coupling efficiency through the dielectric window
Implementation Method 2
an inductively coupled plasma chamber... an annular portion positioned to be substantially disposed below a coil that inductively couples power into the process region
Data Source
AI summary
A dielectric window for a process chamber is provided. The dielectric window includes a disc-shaped body consisting of a first dielectric material having a first dielectric constant. An annular portion consisting of a second dielectric material having a second dielectric constant greater than the first dielectric constant is seated in the disc-shaped body. The dielectric window has a substantially constant thickness over a process region of the process chamber. The process region is an interior region of the process chamber in which a plasma is generated during processing of a substrate in the process chamber. The seating of the annular portion in the disc-shaped body is configured to maintain the substantially constant thickness of the dielectric window.