Lamp Zone Offset Tuning for Uniform Wafer Temperature Control
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Solution Overview
Problem
Existing thermal processing systems face challenges in maintaining uniform temperature during rapid thermal processing of semiconductor wafers due to variations in temperature sensor measurements and differences in sensor positions, leading to inaccuracies in temperature control.
Innovation Solution
A method and apparatus that simulate and adjust lamp zone offset values to determine processing values, allowing for independent control of lamp power on a zone-by-zone basis, improving temperature uniformity by setting final adjusted values to achieve a predetermined goal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical pyrometry is used to measure temperature in RTP systems, then temperature measurement capability is provided, but variations between individual temperature sensors and differences in positions of the individual temperature sensors with respect to a particular substrate in the chamber affect the accuracy of the temperature measurements
Solution Approach 1:
The patent applies parameter changes by adjusting lamp zone offset values and temperature offset values to compensate for sensor variations and position differences. The system determines temperature sensitivity profiles and uses these to calculate corrected temperature measurements that account for individual sensor characteristics and their positions relative to the substrate, thereby improving measurement accuracy and consistency
Solution Approach 2:
The system implements feedback by continuously measuring temperatures with multiple pyrometers, comparing these measurements against target temperature profiles, and adjusting lamp power distribution accordingly. The temperature sensitivity profiles provide a feedback mechanism that allows the system to compensate for sensor variations and maintain accurate temperature control despite differences in individual sensor characteristics
2Temperature
If lamps are divided into zones and controlled together in groups, then temperature control capability is provided, but temperature uniformity across the substrate is difficult to maintain due to sensor variations and position differences
Solution Approach 1:
The patent applies segmentation by dividing the lamp system into multiple independently controllable zones rather than controlling all lamps as a single group. Each lamp zone can be adjusted individually based on temperature sensitivity profiles and measured temperature distributions, allowing precise control of temperature uniformity across different regions of the substrate while maintaining overall temperature control capability
Solution Approach 2:
The system implements local quality by applying different temperature offset values and power adjustments to different lamp zones based on their specific temperature sensitivity profiles and the local temperature requirements of substrate regions. This allows each zone to be optimized for its specific function, improving overall temperature uniformity while maintaining the ability to control temperature across the entire substrate
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 enhances process uniformity by reducing temperature deviations across the substrate, improving control at the edge and center regions, and optimizing power distribution to achieve better thermal treatment consistency.
Implementation Method 1
heat energy radiates from radiation sources into the process chamber and to a semiconductor substrate in the processing chamber
Implementation Method 2
optical pyrometry is used to measure temperature in RTP systems. One or more pyrometers measure emitted radiation intensity from an object and perform an appropriate calculation to obtain a temperature
Data Source
AI summary
A method for controlling temperature in a thermal processing chamber includes determining temperature sensitivity profiles of one or more heating elements or zones for a substrate based on measurements of the substrate. The method also includes selecting a temperature offset value for each of the one or more heating elements or zones. The method also includes simulating the adjustment of each of the one or more zone offset values to a respective final adjusting value that achieves a predetermined goal. The method further includes adjusting the temperature offset values for each of the one or more heating elements to the respective final adjusted values.