Epitaxial Wafer Chamber Control for Temperature and Thickness Uniformity
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving uniform temperature and thickness of films across a wafer during epitaxial growth, which is crucial for precise processing and reducing manufacturing defects.
Innovation Solution
A system utilizing frontside and backside pyrometers in combination with a feedback control system to monitor and adjust temperature and gas flow in real-time, ensuring uniformity by modulating heating source power and gas supply based on in-situ measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pyrometers are used to measure temperatures of films and wafer surfaces, then temperature uniformity and thickness uniformity can be achieved, but device complexity increases due to multiple measurement points and feedback control systems
Solution Approach 1:
The wafer surface is divided into multiple measurement zones (center and edge regions) with separate pyrometers for each zone. This segmentation allows independent temperature measurement and control for different regions, enabling precise compensation of radial temperature gradients while maintaining manageable system complexity through modular measurement points.
Solution Approach 2:
Different measurement and control strategies are applied to different regions of the wafer. The center and edge regions have dedicated pyrometers and independent heating source control, allowing local temperature optimization. This local quality approach ensures uniform film thickness by addressing specific regional temperature variations rather than using a single uniform control strategy.
2Temperature
If multiple heating sources with independent control are used, then temperature uniformity across the wafer can be improved, but device complexity and energy consumption increase
Solution Approach 1:
The heating system is segmented into multiple independently controllable heating sources positioned at different locations (center and edge regions). Each heating source is controlled by a separate controller that receives temperature feedback from corresponding pyrometers, enabling regional temperature adjustment to compensate for radial temperature gradients.
Solution Approach 2:
A feedback control system is implemented where pyrometers continuously measure temperatures at different wafer regions, and controllers independently adjust heating source outputs based on these measurements. This closed-loop feedback ensures temperature uniformity across the wafer while allowing the system to adapt to changing conditions during film deposition.
3Manufacturing precision
If real-time temperature monitoring and control is implemented, then film deposition uniformity is improved, but processing time and energy consumption increase
Solution Approach 1:
Temperature monitoring and control operate continuously throughout the film deposition process rather than in discrete steps. Pyrometers continuously measure wafer surface temperatures, and controllers continuously adjust heating sources, ensuring temperature uniformity is maintained throughout the entire deposition time without interruption or manual intervention.
Solution Approach 2:
Real-time feedback from pyrometers enables immediate detection and correction of temperature deviations during film deposition. This continuous feedback loop prevents temperature non-uniformity from developing, ensuring consistent film quality throughout the process while allowing for efficient processing without repeated measurements or adjustments.
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
Enables real-time monitoring and control of temperature and thickness distribution across the wafer, enhancing uniformity and reducing defects in the epitaxial film growth process.
Implementation Method 1
Pyrometers are often used to measure temperatures of films and wafer surfaces in a semiconductor processing chamber
Implementation Method 2
a first heating source in a first region of the epitaxial growth chamber and a second heating source in a second region of the epitaxial growth chamber
Data Source
AI summary
In an embodiment, an apparatus includes a first pyrometer and a second pyrometer configured to monitor thermal radiation from a first point and a second point on a backside of a wafer, respectively, a first heating source in a first region and a second heating source in a second region of an epitaxial growth chamber, respectively, where a first controller adjusts an output of the first heating source and the second heating source based upon the monitored thermal radiation from the first point and the second point, respectively, a third pyrometer and a fourth pyrometer configured to monitor thermal radiation from a third point and a fourth point on a frontside of the wafer, respectively, where a second controller adjusts a flow rate of one or more precursors injected into the epitaxial growth chamber based upon the monitored thermal radiation from the first, second, third, and fourth points.