Weighted Average Temperature Control for Semiconductor Heat Treatment
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Solution Overview
Problem
Existing heat treatment technologies for semiconductor substrates face challenges in stabilizing temperature control due to differences in measurement accuracy between thermocouples and pyrometers across varying temperature ranges, leading to abrupt changes in heating output and potential thermal stress on the stage.
Innovation Solution
A heat treatment apparatus that employs a weighted average temperature calculation based on measurements from a high-accuracy thermocouple in lower temperatures and a high-accuracy pyrometer in higher temperatures, with a transition zone for smooth control, using a carbon wire heater and a control system to adjust the heating output accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature measurement parts are switched based on temperature range, then measurement accuracy is maintained, but abrupt changes in heating output occur
Solution Approach 1:
The system performs preliminary action by having both temperature measurement parts operate simultaneously in an overlapping temperature range. The controller determines whether to switch between measurement parts based on predetermined temperature thresholds, ensuring smooth transitions and preventing abrupt changes in heating output control.
Solution Approach 2:
The controller acts as an intermediary that manages the transition between different temperature measurement parts. By using predetermined temperature ranges and weighted average calculations, the controller smoothly transitions between measurement sources, preventing abrupt changes in heating output while maintaining measurement accuracy.
2Device complexity
If single temperature measurement part is used, then device complexity is low, but measurement accuracy deteriorates across wide temperature range
Solution Approach 1:
The temperature measurement system is segmented into two specialized measurement parts, each optimized for specific temperature ranges. This segmentation allows the system to maintain high measurement accuracy across a wide temperature range while keeping each individual measurement part relatively simple in design.
Solution Approach 2:
The temperature measurement system achieves multi-functionality by combining two different measurement parts (thermocouple and pyrometer) that can cover different temperature ranges. This universal approach allows a single measurement system to accurately measure temperatures across a broad spectrum, from low to high temperatures.
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 stabilizes the heating output, reduces thermal stress, and prevents damage to the stage by smoothly transitioning the control temperature across the temperature range, ensuring precise and stable heat treatment.
Implementation Method 1
a first temperature measurement part configured to measure a temperature at which the substrate is heated by the heating part
Implementation Method 2
a second temperature measurement part configured to measure the temperature at which the substrate is heated by the heating part, and having a level of measurement accuracy that is lower than a level of measurement accuracy of the first temperature measurement part in a first temperature region lower than a first temperature and is higher than the level of measurement accuracy of the first temperature measurement part in a second temperature region higher than a second temperature which is higher than the first temperature
Implementation Method 3
a heating part configured to change an output for heating the substrate disposed on the substrate
Data Source
AI summary
An apparatus for heat-treating a substrate includes: a stage where the substrate is disposed; a heating part configured to change an output; a first temperature measurement part configured to measure a temperature at which the substrate is heated; a second temperature measurement part configured to measure the temperature, and having a level of measurement accuracy which is lower than that of the first temperature measurement part in a first temperature region and is higher than that of the first temperature measurement part in a second temperature region; a temperature calculator configured to calculate a weighted average temperature of the temperatures measured by the first and second temperature measurement parts if a reference temperature is in a temperature range between the first and second temperatures, and configured to change a weight of the weighted average temperature; and a controller configured to control the output based on the weighted average temperature.