Cryogenic Electrostatic Chuck With Facility Plate Thermal Barrier
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Solution Overview
Problem
Current semiconductor manufacturing techniques face challenges in maintaining substrates at cryogenic temperatures required for next-generation VLSI and ULSI processing, particularly for forming smooth, vertical trenches and improving etching selectivity between materials like silicon and silicon dioxide.
Innovation Solution
A substrate support assembly incorporating an electrostatic chuck (ESC) with resistive heaters and a refrigerant channel, coupled with a facility plate and seal assembly, allows for cryogenic temperature operation by maintaining the substrate at temperatures below -50°C while keeping other chamber surfaces at different temperatures, utilizing a refrigerant chiller and coolant channels for precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is maintained at cryogenic temperatures for improved etching selectivity and reduced spontaneous etching, then etching quality and circuit density are improved, but the device complexity and difficulty of temperature control increase
Solution Approach 1:
The substrate support assembly is divided into distinct thermal zones: the ESC and its base assembly are maintained at cryogenic temperatures through dedicated refrigerant channels, while the facility plate and chamber walls are kept at higher temperatures through separate coolant channels. This segmentation allows independent temperature control of different regions, enabling cryogenic processing without requiring the entire chamber to be cooled.
Solution Approach 2:
A facility plate acts as a thermal intermediary between the cryogenic ESC assembly and the warmer chamber environment. The facility plate includes coolant channels that maintain it at a higher temperature than the ESC, creating a thermal barrier that isolates the cryogenic zone from the chamber walls. This intermediary structure enables localized cryogenic processing while maintaining a manageable chamber temperature.
2Temperature
If refrigerant channels are integrated into the ESC base assembly for cryogenic cooling, then substrate temperature control is improved, but the structural integrity and material selection constraints increase
Solution Approach 1:
The ESC base assembly serves multiple functions: it provides structural support for the ESC, contains integrated refrigerant channels for cryogenic cooling, and acts as a thermal interface between the ESC and the facility plate. By combining these functions into a single multi-functional component, the design reduces the number of separate parts and simplifies the overall structure despite the complex thermal requirements.
Solution Approach 2:
The substrate support assembly utilizes composite construction with the ESC made from ceramic or polymer materials suitable for cryogenic operation, the base assembly providing structural support and thermal conduction, and the facility plate offering thermal isolation. This composite approach allows each component to be made from materials optimized for its specific functional requirements while working together as an integrated system.
3Reliability
If the facility plate is maintained at a higher temperature than the ESC through separate coolant channels, then thermal isolation and vacuum sealing are improved, but the device complexity increases
Solution Approach 1:
The facility plate integrates multiple functions into a single component: it provides structural support for the ESC assembly, contains coolant channels for thermal management, and incorporates sealing surfaces for vacuum isolation. By merging these functions into one integrated plate rather than using separate components, the design reduces overall complexity while maintaining the necessary thermal and vacuum isolation.
Solution Approach 2:
The facility plate incorporates coolant channels that circulate fluid to maintain thermal isolation between the ESC and chamber environment. This hydraulic cooling system provides reliable thermal management and vacuum sealing through the integrated plate structure, avoiding the need for complex mechanical cooling systems or multiple separate sealing 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
Enables uniform maintenance of substrates at cryogenic temperatures, reducing spontaneous etching and enhancing etching selectivity, thereby improving the formation of smooth trenches and increasing circuit density and quality in semiconductor devices.
Implementation Method 1
An ESC base assembly is coupled to the ESC having a refrigerant channel disposed therein
Implementation Method 2
The ESC has a chucking electrode and one or more resistive heaters disposed therein
Implementation Method 3
A vacuum region is defined by the ESC, the ESC base assembly, the plate portion of the facility plate, the flange portion of the facility plate, and the seal assembly
Data Source
AI summary
Embodiments described herein relate to a substrate support assembly which enables a cryogenic temperature operation of an electrostatic chuck (ESC) so that a substrate disposed thereon is maintained at a cryogenic processing temperature suitable for processing while other surfaces of a processing chamber are maintained at a different temperature. The substrate support assembly includes an electrostatic chuck (ESC), an ESC base assembly coupled to the ESC having a refrigerant channel disposed therein, and a facility plate having a coolant channel disposed therein. The facility plate includes a plate portion and a flange portion. The plate portion is coupled to the ESC base assembly and the flange portion coupled to the ESC with a seal assembly. A vacuum region is defined by the ESC, the ESC base assembly, the plate portion of the facility plate, the flange portion of the facility plate, and the seal assembly.