One-Piece Process Kit Shield for PVD Thermal Stress Reduction
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Solution Overview
Problem
Physical Vapor Deposition (PVD) chambers face issues with contamination due to particle shedding from the deposited film caused by thermal stress from coefficient of thermal expansion mismatch, leading to aluminum whisker formation on substrates, which is exacerbated by inadequate cooling of the process kit components.
Innovation Solution
A one-piece process kit shield with an annular heat transfer channel and a cover ring section forming a tortuous path with the deposition ring, enhancing cooling efficiency and reducing thermal stress, while also improving thermal conductivity and plasma uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the process kit components are cooled more effectively, then whisker formation is reduced, but the device complexity increases due to additional cooling structures
Solution Approach 1:
The patent combines the shield and cover ring into a single integrated one-piece component. The shield includes both the main shielding body and the cover ring section as unified structures, eliminating the need for separate cooling systems for each component and reducing overall device complexity while maintaining effective cooling
Solution Approach 2:
The shield is divided into functional sections (main body and cover ring section) with a tortuous path structure that segments the plasma flow and thermal pathways, allowing targeted cooling of different regions to prevent whisker formation without requiring complex external cooling systems
2Object-generated harmful factors
If thermal stress is reduced through better cooling, then particle shedding decreases, but the manufacturing complexity increases
Solution Approach 1:
By merging the shield and cover ring into one piece, the patent eliminates the need for complex assembly procedures and multiple manufacturing steps, reducing manufacturing complexity while effectively reducing thermal stress and particle shedding through integrated cooling
3Temperature
If the cover ring is positioned closer to the substrate, then cooling efficiency improves, but plasma uniformity deteriorates
Solution Approach 1:
The cover ring section has a curved configuration that follows the substrate contour, allowing it to be positioned close to the substrate for effective cooling while maintaining plasma uniformity through its arc-shaped geometry that distributes thermal and plasma loads evenly
4Loss of energy
If a one-piece shield structure is used, then thermal conductivity improves, but the ability to form tortuous paths for plasma control decreases
Solution Approach 1:
The one-piece shield incorporates segmented functional zones including the tortuous path structure formed by the cover ring section, allowing plasma control features to be integrated into the unified structure without compromising thermal conductivity or requiring separate components
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 solution effectively reduces whisker formation and contamination by improving cooling and thermal conductivity, maintaining uniform plasma distribution, and preventing plasma leakage, thus enhancing the processing quality of substrates.
Implementation Method 1
an annular heat transfer channel disposed within the upper portion
Implementation Method 2
annular heat transfer channel
Implementation Method 3
The inventors have observed that the temperature of the cover ring and shield play an important role in cooling the substrate via thermal radiation
Implementation Method 4
Because the substrate is electrostatically chucked to the pedestal
Implementation Method 5
Physical Vapor Deposition (PVD) chambers deposit films on all components surrounding the plasma
Implementation Method 6
a sputtering target disposed in an upper section of the inner volume
Data Source
AI summary
Embodiments of process kit shields and process chambers incorporating same are provided herein. In some embodiments, a one-piece process kit shield configured for use in a processing chamber for processing a substrate having a given diameter includes: a cylindrical body having an upper portion and a lower portion; an annular heat transfer channel disposed within the upper portion; and a cover ring section extending radially inward from the lower portion and having an annular leg extending from a bottom surface of the cover ring section, wherein the annular leg is configured to interface with a deposition ring to form a tortuous path between the bottom surface and the deposition ring.