Replaceable Upper Chamber Section for Plasma Processing
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Solution Overview
Problem
The existing upper chamber sections in plasma processing systems face challenges with thermal mass distribution, leading to temperature variations that affect etch and deposition rates, and are difficult to align and clean, impacting the precision of plasma processing.
Innovation Solution
A replaceable upper chamber section with a monolithic metal cylinder design featuring a conical inner surface, increased thermal mass for uniformity, a thermal choke to minimize heat transfer, and improved sealing surfaces for better alignment and cleaning, constructed from hard anodized aluminum with enhanced mounting and alignment features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the upper chamber section is made with traditional design, then the structure is simpler, but the azimuthal temperature uniformity deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform thermal mass distribution within the upper chamber section. Specifically, a thermal mass component is added to the region where temperature uniformity is needed, while other regions maintain their original design. This localized modification improves azimuthal temperature uniformity without unnecessarily complicating the entire chamber structure.
2Temperature
If the upper chamber section has high thermal mass, then the temperature uniformity improves, but the thermal transfer to bottom chamber section increases
Solution Approach 1:
The upper chamber section is segmented into distinct functional regions: a thermal mass portion for temperature uniformity and a thermal choke portion for heat isolation. This segmentation allows the thermal mass to improve temperature uniformity while the thermal choke segment prevents excessive heat transfer to the bottom chamber section, thereby reducing thermal energy loss.
Solution Approach 2:
The thermal choke acts as an intermediary element between the upper chamber section (with high thermal mass) and the bottom chamber section. It mediates the thermal interaction by providing thermal isolation, allowing the upper section to maintain temperature uniformity without transferring excessive heat to the bottom section, thus reducing thermal energy loss.
3Manufacturing precision
If the upper chamber section is difficult to align, then the manufacturing is simpler, but the manufacturing precision deteriorates
Solution Approach 1:
Alignment features such as protrusions and recesses are pre-formed during the manufacturing process of the upper chamber section. This preliminary action of creating alignment features ensures that when the chamber sections are assembled, the alignment is automatically achieved with high precision without requiring complex alignment procedures during manufacturing or assembly.
4Productivity
If the upper chamber section is difficult to clean, then the structure is simpler, but the productivity deteriorates
Solution Approach 1:
The upper chamber section is designed as a separable component that can be removed from the bottom chamber section. This segmentation allows the upper chamber to be easily detached and cleaned independently without disassembling the entire plasma processing system, thereby improving cleaning efficiency while adding minimal structural complexity through the removable design.
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 achieves improved azimuthal temperature uniformity, reduced thermal transfer to the bottom chamber section, and facilitates easier maintenance, ensuring more precise and consistent plasma processing by minimizing temperature variations and simplifying the cleaning process.
Implementation Method 1
a thermal mass at an upper portion of the cylinder, the thermal mass defined by a portion of the cylinder between the conical inner surface and an outer surface extending vertically from the upper flange, the thermal mass being effective to provide azimuthal temperature uniformity of the conical inner surface
Implementation Method 2
a thermal choke at a lower portion of the cylinder effective to minimize transfer of heat across the lower vacuum sealing surface, the thermal choke defined by a thin metal section having a thickness of less than 0.25 inch and extending at least 25% of the length of the conical inner surface
Implementation Method 3
an upper annular vacuum sealing surface adapted to seal against a dielectric window of the plasma chamber; a lower annular vacuum sealing surface adapted to seal against a bottom section of the plasma chamber
Data Source
AI summary
A replaceable upper chamber section of a plasma reaction chamber in which semiconductor substrates can be processed comprises a monolithic metal cylinder having a conical inner surface which is widest at a lower end thereof, an upper flange extending horizontally outward away from the conical inner surface and a lower flange extending horizontally away from the conical inner surface. The cylinder includes an upper annular vacuum sealing surface adapted to seal against a dielectric window of the plasma chamber and a lower annular vacuum sealing surface adapted to seal against a bottom section of the plasma chamber. A thermal mass at an upper portion of the cylinder is effective to provide azimuthal temperature uniformity of the conical inner surface. A thermal choke is located at a lower portion of the cylinder and is effective to minimize transfer of heat across the lower vacuum sealing surface.