Cryogenic Electrostatic Chuck With Segmented Thermal Zones
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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 base assembly connected to a cryogenic chiller, coupled with a facility plate and seal assembly, creates a vacuum region to maintain substrates at cryogenic temperatures while allowing other chamber surfaces to be at different temperatures, enabling uniform processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the substrate support assembly uses conventional heating methods, then the substrate can be maintained at elevated temperatures, but the assembly cannot achieve uniform cryogenic temperature distribution required for next-generation VLSI processing
Solution Approach 1:
The substrate support assembly is divided into distinct thermal zones: a cryogenic chuck region for substrate cooling and a separate heating region with resistive heaters. This segmentation allows independent temperature control of different areas, enabling the substrate to be maintained at uniform cryogenic temperatures while other components remain at elevated temperatures, thus achieving smooth vertical trenches without thermal distortion
Solution Approach 2:
The assembly implements local quality by providing different thermal conditions to different parts: the substrate contact area is cooled to cryogenic temperatures for precise etching, while the base assembly and heating elements maintain elevated temperatures. This localized temperature control ensures uniform substrate temperature distribution where needed while allowing thermal management elsewhere in the system
2Manufacturing precision
If the substrate is processed at cryogenic temperatures, then etching selectivity between silicon and silicon dioxide improves exponentially, but the substrate support assembly becomes more complex requiring separate temperature zones
Solution Approach 1:
The substrate support assembly is segmented into functionally independent modules: a cryogenic chuck for substrate cooling, a base assembly with resistive heaters for elevated temperature operation, and a facility plate with fluid channels. This modular segmentation achieves the complex temperature zoning requirement while maintaining ease of assembly and maintenance, thus improving etching selectivity without proportionally increasing overall system complexity
Solution Approach 2:
The facility plate serves multiple functions: it provides fluid distribution channels for thermal control, acts as a structural support connecting the chuck to the base assembly, and incorporates sealing elements. This multi-functionality reduces the number of separate components needed, achieving the required temperature zones without excessive complexity in the substrate support assembly
3Manufacturing precision
If the substrate support assembly maintains uniform cryogenic temperature across all components, then substrate processing precision improves, but energy loss increases and other chamber surfaces cannot be maintained at different temperatures
Solution Approach 1:
The assembly segments thermal management into separate zones: the chuck region is isolated for cryogenic substrate cooling while the base assembly and facility plate can be maintained at elevated temperatures through resistive heaters. This segmentation confines cryogenic temperatures only to where needed for substrate processing, reducing thermal energy loss to surrounding components and allowing independent temperature control of different assembly parts
Solution Approach 2:
Cryogenic temperatures are applied locally only to the substrate contact area through the chuck, while other parts of the assembly maintain elevated temperatures. This localized thermal control achieves high substrate processing precision without the energy loss associated with cooling entire assembly components, as thermal insulation and separate heating elements minimize unnecessary thermal energy consumption
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 allows for reliable cryogenic processing of substrates, reducing spontaneous etching and enhancing etching selectivity, resulting in the formation of smooth, vertical trenches and improved material processing outcomes.
Implementation Method 1
The ESC has a chucking electrode and one or more resistive heaters disposed therein
Implementation Method 2
A vacuum region is defined by the ESC, the ESC base assembly, the plate portion of the facility plate, the wall 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 base channel disposed therein, and a facility plate having a facility channel disposed therein. The facility plate includes a plate portion and a wall portion. The plate portion is coupled to the ESC base assembly and the wall 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 wall portion of the facility plate, and the seal assembly.