Multi-zone Pedestal Temperature Control via Sensor Placement
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Solution Overview
Problem
Existing substrate processing systems face challenges in maintaining thermal uniformity across multiple zones of a substrate support, requiring direct or indirectly calibrated temperature measurements.
Innovation Solution
A substrate support assembly with M resistive heaters arranged in M zones and N temperature sensors at specific locations, controlled by a system that adjusts heater power based on local temperature measurements and average zone temperatures to achieve a target temperature profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct temperature measurement in each zone is implemented, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by placing temperature sensors at strategic locations that can infer the temperature state of multiple heater zones. The sensors measure temperature at specific points (center and boundary locations) which then serve as proxies for understanding the thermal state across the entire substrate support, eliminating the need for direct measurement in every zone while maintaining control precision.
Solution Approach 2:
The patent creates a simplified representation of the temperature distribution by using a reduced set of sensors that copy the essential temperature information needed for control. Instead of measuring temperature at every zone, the system uses a subset of sensors positioned at critical locations (center and boundaries) that provide sufficient information to reconstruct and control the overall temperature profile through mathematical modeling.
2Device complexity
If individually calibrated indirect temperature measurement is used, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The patent implements feedback control by continuously measuring temperature at specific locations and using this information to adjust the heater zones. The system measures temperature at the center and boundary locations, compares these against target values, and modifies heater power accordingly. This closed-loop feedback mechanism achieves precise temperature control without requiring complex calibration procedures for each individual zone.
Solution Approach 2:
The patent segments the substrate support into distinct regions (center zone and boundary zones) with different temperature control strategies. By dividing the control problem into manageable segments and applying targeted heating and sensing to each region, the system achieves precise temperature control while keeping the overall system design relatively simple and avoiding the need for fully calibrated individual zone measurements.
3Stability of the object's composition
If multiple temperature sensors are placed in each zone, then temperature uniformity is improved, but loss of energy increases
Solution Approach 1:
The patent applies partial action by placing temperature sensors only at critical locations (center and boundary points) rather than throughout every zone. This selective sensing approach provides sufficient information to maintain temperature uniformity across the substrate support while minimizing the number of sensors and associated energy consumption. The system achieves adequate temperature control with a reduced sensor array by strategically positioning sensors where they provide the most informative data.
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 effectively controls temperature distribution across the substrate, reducing film thickness non-uniformity and enabling precise temperature management for semiconductor processing.
Implementation Method 1
M resistive heaters respectively arranged in M zones in a layer of the substrate support assembly
Implementation Method 2
N temperature sensors arranged at N locations in the layer
Data Source
AI summary
A substrate support assembly includes a baseplate including a layer adjacent to a substrate, M resistive heaters respectively arranged in M zones in the layer, and N temperature sensors arranged at N locations in the layer. M and N are integers, and N is less than or equal to M. The M zones include a first circular zone located at a center region of the layer, a second annular zone surrounding the first circular zone, and a first set of zones located in a first annular region surrounding the second annular zone. The N temperature sensors include a first pair of temperature sensors located at a first boundary between the second annular zone and the first set of zones along a first diameter of the layer, and a first temperature sensor located in the first circular zone at an intersection of the first and second diameters.