Low-Temperature Electrostatic Chuck for Uniform Etch Rate Control
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Solution Overview
Problem
Conventional etching processes face challenges in achieving uniform temperature and etch rate across substrates, especially when processing materials like silicon germanium at low temperatures, due to non-uniform chucking forces and simple heater systems.
Innovation Solution
The use of electrostatic chuck assemblies with multi-zone heating assemblies and thermal insulators, which provide uniform chucking force and allow for precise temperature control of the substrate, enhancing temperature and etch rate uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vacuum chucks are used for low temperature etching, then substrate holding is achieved, but temperature uniformity and etch rate uniformity deteriorate due to non-uniform chucking forces and simple heater systems
Solution Approach 1:
The chuck assembly is segmented into multiple functional zones: an electrostatic chuck portion with distributed electrodes for uniform substrate holding, a heating portion with multiple heating zones for temperature uniformity, and a cooling portion with thermal insulators. This segmentation allows each zone to independently address specific requirements, achieving overall etch rate uniformity without excessive complexity
Solution Approach 2:
The chuck assembly integrates multiple functions into a single unified structure: substrate holding (electrostatic chuck), heating (heating portion with multiple zones), cooling (cooling portion with thermal insulators), and gas distribution (gas channels). This multi-functionality eliminates the need for separate components, achieving temperature and etch rate uniformity while controlling device complexity
2Temperature
If simple heater systems are used, then device complexity is reduced, but temperature uniformity across the substrate deteriorates
Solution Approach 1:
The heating portion is divided into multiple heating zones with independently controllable heating elements. Each zone can be adjusted to provide the appropriate heat distribution across different areas of the substrate, ensuring temperature uniformity. The cooling portion similarly uses multiple cooling zones with thermal insulators to maintain local temperature control
Solution Approach 2:
The heating and cooling systems are equipped with temperature sensors that provide feedback to the control system. This allows real-time adjustment of heating and cooling power to maintain uniform temperature distribution across the substrate, compensating for any local temperature variations
3Manufacturing precision
If non-uniform chucking forces are applied, then electrostatic chuck operation is simplified, but substrate stress and etch rate uniformity deteriorate
Solution Approach 1:
The electrostatic chuck portion is divided into multiple electrode zones that can be independently controlled. This segmentation allows the system to apply non-uniform chucking forces to different areas of the substrate as needed, improving substrate processing uniformity while maintaining manageable control complexity through zoned operation
Solution Approach 2:
The electrostatic chuck system can dynamically adjust the voltage and charge distribution across different electrode zones to optimize chucking forces. By changing electrical parameters in different regions, the system achieves uniform substrate holding and processing while keeping the control system relatively simple
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 enables more uniform substrate processing, reduces stress on substrates, and improves the quality of etched structures by maintaining consistent temperature and etch rates across the substrate surface.
Implementation Method 1
electrostatic chuck assemblies with multi-zone heating assemblies and thermal insulators, which provide uniform chucking force
Implementation Method 2
multi-zone heating assemblies... allow for precise temperature control of the substrate, enhancing temperature and etch rate uniformity
Implementation Method 3
thermal insulators, which provide uniform chucking force and allow for precise temperature control of the substrate
Implementation Method 4
The puck may include a second plate that defines one or more cooling channels for a heat exchange fluid
Data Source
AI summary
Exemplary semiconductor processing chambers may include a chamber body. The chambers may include a showerhead positioned atop the body. The chambers may include an electrostatic chuck assembly disposed within the body. The assembly may include a puck that may include a first plate including an electrically insulating material and that defines a substrate support surface. The puck may include a multi-zone heating assembly thermally coupled with the first plate. The puck may include bipolar electrodes. The puck may include a second plate that defines cooling channels. The assembly may include an insulator beneath the second plate. The assembly may include a base plate beneath the insulator. The assembly may include a shaft that may include a heater rod coupled with the heating assembly. The shaft may include a cooling fluid lumen fluidly coupled with the cooling channels. The shaft may include a power rod electrically coupled with a bipolar electrode.