RTP Thermal Model Fine-Tuning for Uniform Wafer Temperature Profiles
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Solution Overview
Problem
Existing rapid thermal processing (RTP) tools face challenges in achieving precise temperature control due to the mismatch between the number of lamp zones and temperature sensor zones, making it difficult to achieve center flat or other desired temperature profiles.
Innovation Solution
Implementing a method that combines temperature sensor offsets and zone multipliers within a thermal model to generate a target temperature profile, using gain curves derived from metrology data to adjust temperature feedback and lamp power independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pyrometer is used to measure temperatures for multiple lamp zones, then the device complexity is reduced, but the temperature control precision deteriorates
Solution Approach 1:
The patent segments the temperature measurement function by creating multiple virtual temperature sensor readings from a single physical pyrometer. The pyrometer measures light intensity at different wavelengths, and the system processes these measurements to generate multiple independent temperature readings corresponding to different lamp zones, enabling zone-specific temperature control without requiring multiple physical sensors
Solution Approach 2:
The patent changes the measurement parameters by utilizing multi-wavelength light detection. The single pyrometer measures light intensity across multiple wavelengths (e.g., 650nm, 850nm, 1050nm), and the system transforms these spectral measurements into multiple temperature readings through mathematical processing, effectively creating additional measurement dimensions from a single sensor
2Adaptability or versatility
If the number of lamp zones exceeds the number of temperature sensors, then the temperature profile control capability is improved, but the device complexity increases
Solution Approach 1:
The patent introduces an intermediary processing system that bridges the gap between the single pyrometer and multiple lamp zones. This intermediary includes a controller that performs mathematical transformations on the pyrometer readings, generating virtual temperature signals for each lamp zone based on the spectral measurements, thereby enabling multi-zone control without requiring proportional increases in physical sensors
Solution Approach 2:
The patent adds a spectral dimension to the temperature measurement process. By measuring light intensity across multiple wavelengths simultaneously, the system creates an additional measurement dimension that can be mathematically decomposed into multiple temperature readings, effectively increasing the information content from a single sensor to match multiple control zones
3Measurement precision
If multiple temperature sensors are used for each lamp zone, then the temperature feedback resolution is improved, but the device complexity and cost increase
Solution Approach 1:
The patent creates virtual copies of temperature sensor readings through mathematical processing. The single pyrometer's multi-wavelength measurements are processed to generate multiple independent temperature readings that behave as if they came from separate physical sensors, providing the resolution of multiple sensors without the hardware complexity
Solution Approach 2:
The patent replaces the mechanical approach of using multiple physical sensors with a computational approach. Instead of physically distributing multiple pyrometers across different zones, the system uses mathematical algorithms to process the single pyrometer's spectral data and generate zone-specific temperature feedback, substituting hardware complexity with software processing
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
Enhances the resolution of temperature control, allowing for the achievement of uniform temperature profiles across semiconductor substrates, such as center flat or edge hot/cold profiles, by compensating for the limitations of single pyrometer feedback.
Implementation Method 1
An RTP tool includes an array of lamps that are used to heat the underlying substrate
Implementation Method 2
the control of the heating can be informed by feedback provided by one or more temperature sensors, such as pyrometers
Data Source
AI summary
Embodiments disclosed herein include a method of setting a target profile. In an embodiment, the method comprises obtaining a first gain curve for one or more temperature sensor offsets, and obtaining a second gain curve for one or more zone multipliers. In an embodiment, the method further comprises combining the first gain curve and the second gain curve into a thermal model. In an embodiment, the method further comprises obtaining a reference data set, and using the thermal model to generate temperature sensor offsets and/or zone multipliers to apply to the reference data set in order to generate the target profile.