Multi-Zoned Plasma Electrostatic Chuck Temperature Control
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Solution Overview
Problem
In plasma processing for microelectronics, increased power densities lead to challenges in temperature uniformity and control, particularly with rapid temperature setpoint changes, resulting in localized hot and cold spots due to inadequate cooling and the need to deliver both RF power and DC voltage uniformly.
Innovation Solution
An electrostatic chuck assembly with inner and outer fluid conduits arranged azimuthally around a central axis, a thermal break to improve temperature control independence, and a fluid distribution plate to manage heat transfer fluid flow, ensuring uniform heating/cooling and simultaneous delivery of RF and DC power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power density is increased to meet fabrication requirements, then processing capability is improved, but temperature uniformity deteriorates due to inadequate cooling
Solution Approach 1:
The chuck is divided into multiple independently controllable thermal zones with separate coolant channels. Each zone can be cooled at different rates to maintain uniform temperature across the entire chuck surface despite high power density processing in specific areas.
Solution Approach 2:
Different regions of the chuck are provided with customized cooling characteristics through variable coolant channel configurations. Areas experiencing higher power density receive enhanced cooling, while other regions maintain standard cooling to achieve overall temperature uniformity.
2Speed
If thermal time constant is reduced for rapid temperature control, then responsiveness is improved, but localized temperature variation worsens
Solution Approach 1:
The coolant distribution system is segmented into multiple zones with independent flow control. This allows rapid temperature adjustments in specific regions without causing thermal shock or localized variations in other areas, maintaining overall temperature uniformity while achieving fast response.
Solution Approach 2:
The cooling system incorporates dynamic flow control capabilities that adjust coolant distribution in real-time based on processing requirements. This enables rapid temperature changes while maintaining uniform cooling across the chuck surface through coordinated zone control.
3Adaptability or versatility
If coolant loop is designed for legacy chuck, then compatibility is improved, but temperature uniformity in contemporary chuck deteriorates due to pattern formation
Solution Approach 1:
The coolant system is designed with modular, independently controllable zones rather than a single unified loop. This segmentation allows the same coolant infrastructure to be adapted to different chuck designs and power distribution patterns, preventing the formation of temperature patterns while maintaining compatibility with existing coolant loops.
4Manufacturing precision
If RF power and DC voltage are delivered uniformly, then processing quality is improved, but thermal management becomes more difficult due to competing routing requirements
Solution Approach 1:
The chuck incorporates spatially separated zones for RF power delivery and DC voltage application, with coolant channels strategically positioned to cool each region according to its specific thermal load. This segmented approach allows uniform processing quality through coordinated multi-zone control while simplifying thermal management by addressing each region's cooling needs independently.
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 enhances temperature uniformity across the workpiece by optimizing heat transfer fluid flow and reducing thermal cross-talk, allowing for precise temperature control and uniform application of RF and DC power, addressing the challenges of increased power densities in plasma processing.
Implementation Method 1
The fluid conduits are to conduct a heat transfer fluid, such as Galden, Fluorinert, ethylene glycol/water, or the like to heat/cool the top surface of the chuck and workpiece disposed thereon
Implementation Method 2
a thermal break disposed within the cooling channel base between the inner and outer fluid conduits to improve the independence of temperature control between the inner and outer portions of the top surface
Implementation Method 3
Both RF power and DC voltage are also to be delivered in a uniform manner, making their individual routing within a chuck competitive with that of heat/cooling power
Data Source
AI summary
An electrostatic chuck assembly including a dielectric layer with a top surface to support a workpiece. A cooling channel base disposed below the dielectric layer includes a plurality of inner fluid conduits disposed beneath an inner portion of the top surface, and a plurality of outer fluid conduits disposed beneath an outer portion of the top surface. A chuck assembly includes a thermal break disposed within the cooling channel base between the inner and outer fluid conduits. A chuck assembly includes a fluid distribution plate disposed below the cooling channel base and the base plate to distribute a heat transfer fluid delivered from a common input to each inner or outer fluid conduit. The branches of the inner input manifold may have substantially equal fluid conductance.