Adaptive Control Algorithm for Rapid Thermal Processing Substrates
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Solution Overview
Problem
Current rapid thermal processing (RTP) technologies face challenges in achieving precise temperature control and uniformity across semiconductor substrates, particularly due to variations in substrate optical properties and chamber design, leading to sub-optimal peak temperature repeatability and increased temperature non-uniformity.
Innovation Solution
The implementation of a real-time adaptive control algorithm or a suite of fixed control algorithms selected based on measured substrate properties, combined with a binned controller method, allows for improved peak temperature repeatability and reduced temperature non-uniformity by dynamically adjusting lamp power and using a combination of adaptive and computationally less intensive control algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single model-based control algorithm is used for all substrates, then the control is computationally efficient, but the peak temperature repeatability deteriorates due to variations in substrate optical properties
Solution Approach 1:
The patent changes the optical property parameters (emissivity, absorptivity, reflectivity) used in the control algorithm based on measured substrate characteristics. By adjusting these parameters dynamically rather than using fixed values, the system adapts to different substrate types and maintains accurate temperature control across variations in optical properties, thereby improving peak temperature repeatability without sacrificing computational efficiency.
Solution Approach 2:
The patent implements feedback by measuring actual substrate temperature and optical properties during processing, then using this information to adjust the control algorithm parameters in real-time. This closed-loop approach allows the system to compensate for variations in substrate optical properties and maintain consistent peak temperature repeatability across different substrate types.
2Manufacturing precision
If multiple substrate-specific control algorithms are used, then the peak temperature repeatability is improved, but the device complexity and tuning requirements increase
Solution Approach 1:
The patent creates a universal control algorithm that can handle multiple substrate types by incorporating adaptive parameter adjustment capabilities. Rather than maintaining separate algorithms for each substrate type, the single algorithm automatically adapts its parameters based on measured substrate optical properties, thereby achieving substrate-specific control accuracy without the complexity of multiple dedicated algorithms.
Solution Approach 2:
The control algorithm performs self-adjustment by automatically measuring substrate optical properties and modifying its own parameters based on these measurements. This self-service capability eliminates the need for manual tuning and complex configuration for different substrate types, reducing device complexity while maintaining high peak temperature repeatability.
3Manufacturing precision
If model-based control is used to improve temperature control accuracy, then the manufacturing precision is improved, but the computational intensity increases
Solution Approach 1:
The patent dynamically adjusts model parameters based on measured substrate optical properties rather than using fixed or overly complex models. By changing parameters adaptively, the system maintains high temperature control accuracy while avoiding the computational burden of continuously updating complex physical models, thus reducing computational intensity.
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 enables precise control of substrate temperature, improving peak temperature repeatability and minimizing temperature non-uniformity across a wide range of substrates with minimal tuning, allowing for accurate tracking of the desired time-temperature trajectory during RTP.
Implementation Method 1
The substrate temperature is increased using high-intensity lamps
Implementation Method 2
The substrate temperature is increased using high-intensity lamps
Implementation Method 3
measured by a pyrometer
Data Source
AI summary
The present invention generally relates to methods for the rapid thermal processing (RTP) of a substrate. Embodiments of the invention include controlling a thermal process using either a real-time adaptive control algorithm or by using a control algorithm that is selected from a suite of fixed control algorithms designed for a variety of substrate types. Selection of the control algorithm is based on optical properties of the substrate measured during the thermal process. In one embodiment, a combination of control algorithms are used, wherein the majority of lamp groupings are controlled with a fixed control algorithm and a substantially smaller number of lamp zones are controlled by an adaptive control algorithm.