Two-Piece Shutter Disk Self-Centering Thermal Expansion
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Solution Overview
Problem
Conventional shutter disks in process chambers deform due to thermal mismatch and material deposition, leading to gaps that expose the substrate support to plasma, causing issues like arcing, sticking, and reduced electrostatic chucking force, and existing solutions such as reduced RF powers and cooling gases do not adequately address these problems.
Innovation Solution
A two-piece shutter disk assembly comprising an upper disk member and a lower carrier member with self-centering and annular alignment features, allowing independent thermal expansion and contraction, and an electrically insulated barrier to prevent arcing, is introduced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If shutter disk thickness and weight are minimized for robot handling, then ease of operation is improved, but manufacturing precision deteriorates due to increased deformation during thermal processes
Solution Approach 1:
The shutter disk is divided into two separate components: a thin upper disk member (0.02-0.06 inches) for ease of handling and a thicker lower carrier member (0.125-0.25 inches) for structural stability. This segmentation allows each component to be optimized independently - the upper disk remains thin for robot manipulation while the lower carrier provides sufficient thickness to resist thermal deformation and maintain flatness during processing operations.
2Strength
If shutter disk material stiffness is increased to resist deformation, then manufacturing precision is improved, but weight increases making robot handling more difficult
Solution Approach 1:
The shutter disk system is segmented into two parts with different material properties optimized for their specific functions. The upper disk member uses lighter materials (stainless steel, aluminum, or ceramic) that are sufficient for blocking plasma when thin, while the lower carrier member uses stiffer materials (stainless steel or ceramic) that provide the necessary resistance to thermal deformation. This segmentation allows the system to achieve both light weight for handling and high stiffness for deformation resistance.
Solution Approach 2:
The two-piece construction creates a composite structure where materials with different mechanical properties are combined. The upper disk can be made from lighter materials optimized for plasma blocking, while the lower carrier uses denser, stiffer materials optimized for thermal stability and structural support. This composite approach allows the system to achieve properties that neither component could provide alone.
3Manufacturing precision
If cooling power is increased to reduce thermal deformation, then manufacturing precision is improved, but energy consumption increases
Solution Approach 1:
The shutter disk is segmented into two thermally independent components that can be cooled separately. The lower carrier member, which generates the most heat during plasma exposure, has direct thermal pathways to the chamber wall through its thicker construction and mounting structure. The upper disk member, being thinner and lighter, requires less cooling energy to maintain acceptable temperature differentials. This segmentation allows cooling energy to be applied more efficiently to where it is most needed.
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 two-piece shutter disk assembly effectively manages thermal expansion, reducing substrate support exposure to undesired material deposition and preventing arcing during processes like pasting, thereby enhancing process chamber performance and substrate protection.
Implementation Method 1
allowing independent thermal expansion and contraction
Implementation Method 2
an electrically insulated barrier to prevent arcing
Data Source
AI summary
Two-piece shutter disk assemblies for use in process chambers are provided herein. In some embodiments, a shutter disk assembly for use in a process chamber includes an upper disk member having a top surface and a bottom surface, wherein a central alignment recess is formed in a center of the bottom surface, and a lower carrier member having a solid base having an upper support surface, wherein the upper support surface includes a first central self-centering feature disposed in the recess formed in the center of the bottom surface and an annular outer alignment feature that protrudes upward from a top surface of the lower carrier and forms a pocket, wherein the upper disk member is disposed in the pocket.