Rotating Lift Pad for Azimuthal Uniformity in Semiconductor Processing
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Solution Overview
Problem
Semiconductor substrate processing systems face challenges in compensating for non-uniformities in film deposition and etching processes, particularly in achieving uniform film thickness across the substrate due to radial and azimuthal variations, which existing technologies struggle to address effectively.
Innovation Solution
A substrate processing system with a multi-zone resistive heater substrate support and a controller that adjusts temperature zones and rotates a lift pad to compensate for non-uniformities by aligning the substrate with predetermined positions and temperature profiles, thereby averaging out variations across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional substrate processing system uses a single-zone heater, then the device complexity is low, but the manufacturing precision of film thickness uniformity deteriorates due to radial and azimuthal non-uniformities
Solution Approach 1:
The substrate support heater is divided into multiple independently controllable zones (e.g., inner zone, outer zone, intermediate zones) with different temperature profiles. This segmentation allows different radial regions of the substrate to receive optimized heating, compensating for radial non-uniformities in film deposition and enabling precise control of film thickness uniformity across the substrate surface.
Solution Approach 2:
Each heater zone is assigned a specific temperature profile tailored to the local requirements of that radial region. The inner zones may operate at higher temperatures to compensate for lower deposition rates near the center, while outer zones use lower temperatures to prevent excessive deposition at the edges. This local quality approach optimizes film uniformity by addressing the specific needs of each spatial region.
2Manufacturing precision
If the substrate support rotates the substrate during processing, then the azimuthal non-uniformities are averaged out improving film uniformity, but the device complexity and processing time increase
Solution Approach 1:
The substrate is pre-positioned at specific angular orientations corresponding to azimuthal non-uniformity patterns before processing begins. By aligning the substrate's radial features with the multi-zone heater's optimized temperature profiles in advance, the system compensates for azimuthal variations without requiring rotation during the actual deposition process, thus maintaining fast processing cycles.
Solution Approach 2:
The substrate support performs periodic rotations at controlled intervals during the deposition process. Rather than continuous rotation, the substrate is rotated to predetermined angular positions at specific time points, allowing the deposition process to continue with minimal interruption while still achieving averaging of azimuthal non-uniformities over the complete deposition cycle.
3Manufacturing precision
If multiple independently controllable heater zones are implemented, then radial non-uniformities are compensated improving film thickness control, but the control system complexity and energy consumption increase
Solution Approach 1:
The controller dynamically adjusts the temperature parameters of each heater zone based on real-time feedback from substrate temperature sensors and deposition rate monitors. By continuously optimizing the temperature distribution across different zones, the system achieves precise radial film thickness control while minimizing energy consumption by avoiding excessive heating in regions where it is not needed.
Solution Approach 2:
The system incorporates temperature sensors and deposition rate monitors that provide real-time feedback to the controller. This feedback enables the controller to adjust the power supplied to each heater zone dynamically, compensating for radial non-uniformities while optimizing energy distribution. Zones requiring less heating receive reduced power, minimizing overall energy consumption while maintaining film uniformity.
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 approach effectively compensates for both radial and azimuthal non-uniformities, improving film thickness uniformity and reducing the impact of previous processing steps' variations, enhancing the precision of deposition and etching processes.
Implementation Method 1
a plurality of resistive heaters arranged throughout the plurality of zones. The plurality of resistive heaters includes separately-controllable resistive heaters arranged in respective ones of the plurality of zones
Data Source
AI summary
A substrate processing system includes a substrate support and a controller. The substrate support includes a lift pad, a plurality of zones, and a plurality of resistive heaters arranged throughout the plurality of zones. The plurality of resistive heaters includes separately-controllable resistive heaters arranged in respective ones of the plurality of zones. The controller is configured to determine a rotational position of a substrate arranged on the lift pad, selectively rotate the lift pad to adjust the substrate to the rotational position, and control the plurality of resistive heaters to selectively adjust temperatures within the plurality of zones based on the rotational position.