Electrostatic Chuck Structure for Uniform Plasma Edge Processing
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Solution Overview
Problem
In plasma processing, achieving uniformity of the electric field across the substrate and focus ring is challenging, and existing electrostatic chucks are prone to damage from plasma processing due to exposure to chemical species.
Innovation Solution
An electrostatic chuck design with a first region for holding the substrate and a second region for supporting the focus ring, both having a single flat upper surface with a space in between to reduce electric field differences and protect the chuck from plasma damage, where the focus ring is mounted on the second region with its second portion accommodated in this space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the electrostatic chuck has a flat upper surface with substrate and focus ring regions, then the manufacturing precision is improved, but the electric field uniformity deteriorates
Solution Approach 1:
The electrostatic chuck is segmented into a substrate holding region and a focus ring support region, with each region having independent height adjustment capability. This allows the flat upper surface requirement to be met while compensating for electric field non-uniformity through differential height positioning of the two regions.
2Reliability
If the focus ring is mounted close to the substrate edge, then the processing uniformity is improved, but the electrostatic chuck is exposed to plasma damage
Solution Approach 1:
The focus ring is nested within a protective groove structure on the electrostatic chuck surface. The groove accommodates the focus ring while providing a physical barrier that shields the electrostatic chuck substrate from direct plasma exposure, thus maintaining processing uniformity while reducing plasma damage.
3Reliability
If the focus ring surrounds the substrate edge, then the processing uniformity is improved, but the structural complexity increases
Solution Approach 1:
The focus ring support function is merged with the electrostatic chuck body by integrating the focus ring mounting structure directly into the chuck's upper surface. This eliminates the need for separate focus ring mounting fixtures or additional support components, reducing overall structural complexity while maintaining the focus ring's uniformity-improving function.
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 design reduces the electric field difference between the substrate and focus ring, minimizing damage to the electrostatic chuck by shielding it from plasma species, thereby enhancing processing uniformity and chuck durability.
Implementation Method 1
an electrostatic chuck (20) is provided in the plasma processing apparatus (1). The substrate (W) is held by the electrostatic chuck (20)
Implementation Method 2
In the plasma processing, a plasma processing apparatus is used. The plasma processing apparatus is provided with a chamber and a support base
Data Source
AI summary
An electrostatic chuck according to an exemplary embodiment includes a first region and a second region. The first region has a first upper surface. The first region is configured to hold a substrate disposed on the first upper surface. The second region has a second upper surface. The second region extends in a circumferential direction to surround the first region. The second region is configured to support a focus ring mounted on the second upper surface. The first upper surface and the second upper surface extend along a single flat surface. The first region and the second region provide a space therebetween to separate the first upper surface and the second upper surface from each other.