Edge-Clamping Cover Ring for Flattening Thin Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thin semiconductor substrates tend to bow during processing in deposition chambers, leading to process non-uniformity, and bonding them to carrier plates adds unnecessary processing time and complexity.
Innovation Solution
A process kit with a cover ring featuring an annular body and protrusions is used to clamp the substrate's outer rim, providing mechanical flattening without the need for bonded carriers, minimizing contact and preventing plasma arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thin substrates are processed without bonding to carrier plates, then processing time is reduced and tooling complexity is decreased, but substrates bow resulting in process non-uniformity
Solution Approach 1:
The cover ring is segmented with multiple protrusions distributed around its inner circumference, allowing localized contact points with the substrate edge rather than continuous contact. This segmentation provides sufficient flattening force while minimizing overall contact area, preventing plasma arcing between protrusions and substrate
Solution Approach 2:
The invention extracts the substrate flattening function from the bonding process. Instead of bonding the entire substrate to a carrier plate for flattening, only the substrate edge is clamped by the cover ring protrusions, separating the flattening function from the substrate support function and eliminating the need for bonding operations
2Manufacturing precision
If substrates are bonded to carrier plates for flattening, then substrate flatness is improved, but processing time increases due to additional bonding and debonding steps
Solution Approach 1:
The invention extracts the substrate flattening function from the bonding process. Instead of bonding the entire substrate to a carrier plate for flattening, only the substrate edge is clamped by the cover ring protrusions, separating the flattening function from the substrate support function and eliminating the need for bonding operations
Solution Approach 2:
The cover ring with protrusions provides self-adjusting clamping force on the substrate edge. The protrusions naturally conform to the substrate edge geometry and apply distributed flattening force without requiring external bonding agents or additional tooling, making the flattening process self-contained within the existing chamber components
3Force
If the cover ring makes extensive contact with the substrate, then clamping force is improved, but plasma arcing occurs between contact points
Solution Approach 1:
The cover ring is segmented with multiple protrusions distributed around its inner circumference, allowing localized contact points with the substrate edge rather than continuous contact. This segmentation provides sufficient flattening force while minimizing overall contact area, preventing plasma arcing between protrusions and substrate
Solution Approach 2:
The protrusions create localized contact zones with high clamping force density at discrete points along the substrate edge. Each protrusion provides concentrated local pressure to maintain substrate flatness while the gaps between protrusions prevent plasma discharge paths, achieving both adequate clamping and arc prevention through spatial distribution
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 effectively flattens thin substrates, reducing processing time by eliminating the need for bonding and debonding steps while maintaining adequate clamping force and preventing unwanted deposition.
Implementation Method 1
raising the substrate support to clamp an outer rim of the substrate against a cover ring
Implementation Method 2
the substrate may be retained to the substrate support via electrostatic chucking
Data Source
AI summary
Embodiments of process kits for use in a process chamber are provided herein. In some embodiments, a cover ring for use in a process chamber includes: an annular body that includes an upper surface and a lower surface, an inner lip extending radially inward and downward from the annular body, and a plurality of protrusions extending downward from the inner lip and disposed at regular intervals along the inner lip, wherein lowermost surfaces of the plurality of protrusions together define a planar substrate contact surface.