Symmetrical Feed Structure for Substrate Support Etch Uniformity
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Solution Overview
Problem
As critical dimensions of devices shrink, existing substrate processing technologies face challenges in achieving uniform etch rates and dimensions due to asymmetric electrical feed structures, leading to process non-uniformities.
Innovation Solution
A substrate support with a symmetrical electrical feed structure, including a tubular inner conductor, an outer conductor electrically isolated by a dielectric layer, and symmetrically arranged conductors to provide RF, AC, and DC power, which confines and uniformly distributes electric and magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an asymmetric electrical feed structure is used to provide power to the substrate, then the device complexity is reduced, but the etch rate uniformity and etch dimension uniformity deteriorate due to electromagnetic skew and process non-uniformities
Solution Approach 1:
The patent applies asymmetry principle by intentionally designing a symmetric electrical feed structure in an otherwise asymmetric configuration. The symmetric feed structure includes conductors arranged symmetrically about the central axis, which compensates for the asymmetry introduced by the off-axis RF power source, thereby minimizing electromagnetic skew and improving etch uniformity while maintaining practical device complexity
2Manufacturing precision
If a symmetric electrical feed structure is implemented to improve etch uniformity, then the etch rate uniformity and etch dimension uniformity improve, but the device complexity increases due to additional conductors and dielectric layers
Solution Approach 1:
The patent applies local quality principle by making only the critical electrical feed components symmetric (the conductors providing RF, AC, and DC power to the substrate), while other parts of the system can remain asymmetric. This localized symmetry approach improves etch uniformity without requiring complete symmetry throughout the entire device, thereby limiting the increase in overall device complexity
3Stability of the object's composition
If multiple conductors (inner, outer) with dielectric isolation are used to minimize electromagnetic skew, then the electromagnetic field uniformity improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies the nesting principle by placing the inner conductor inside the outer conductor, with the dielectric layer nested between them. This nested configuration creates a coaxial structure that effectively minimizes electromagnetic skew and improves field uniformity. The nested design is more space-efficient and easier to manufacture than separate symmetric conductors, as it reduces the overall footprint and simplifies assembly
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 improves etch rate and etch dimension uniformity by minimizing electromagnetic skew and ensuring consistent power distribution to the substrate, enhancing processing performance.
Implementation Method 1
an outer dielectric layer disposed between the inner and outer conductors, the outer dielectric layer electrically isolating the outer conductor from the inner conductor
Implementation Method 2
confines and uniformly distributes electric and magnetic fields
Data Source
AI summary
Apparatus for processing a substrate is disclosed herein. In some embodiments, a substrate support may include a substrate support having a support surface for supporting a substrate the substrate support having a central axis; a first electrode disposed within the substrate support to provide RF power to a substrate when disposed on the support surface; an inner conductor coupled to the first electrode about a center of a surface of the first electrode opposing the support surface, wherein the inner conductor is tubular and extends from the first electrode parallel to and about the central axis in a direction away from the support surface of the substrate support; an outer conductor disposed about the inner conductor; and an outer dielectric layer disposed between the inner and outer conductors, the outer dielectric layer electrically isolating the outer conductor from the inner conductor. The outer conductor may be coupled to electrical ground.