Multi-Zone Temperature Control Using Heat-Coupled State-Space Models
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Solution Overview
Problem
In semiconductor manufacturing, controlling the temperature distribution of a substrate with high precision is challenging due to the difficulty in providing heaters and temperature sensors in each independently controllable area as the number of areas increases, leading to slow stabilization of temperature control.
Innovation Solution
A model-based control method that includes acquiring temperature control data, specifying weight-averaged temperatures using heat transfer coefficients, creating a state-space model, and controlling the temperature of each zone using multi-input/multi-output models to stabilize temperature distribution quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of independently controllable areas on the stage is increased, then the temperature distribution control precision is improved, but the device complexity increases and it becomes difficult to provide both heater and temperature sensor in all areas
Solution Approach 1:
The patent uses resistance value measurement as a substitute for direct temperature sensing. The heater's resistance value serves as a proxy indicator of its temperature, eliminating the need for separate temperature sensors in each zone. This copying approach allows temperature monitoring and control in multiple zones without increasing device complexity
Solution Approach 2:
The heater is given dual functionality: it serves both as a heating element and as a temperature sensing element through resistance measurement. This multi-functionality resolves the contradiction by allowing temperature control in multiple zones without requiring additional dedicated sensing components for each zone
2Manufacturing precision
If the number of independently controllable areas on the stage is increased, then the temperature distribution control precision is improved, but the stabilization time increases
Solution Approach 1:
The patent implements feedback control by continuously measuring the resistance values of heaters in different zones and using this information to adjust power distribution. The control unit calculates required power changes based on resistance value deviations from target values, enabling rapid stabilization of temperature distribution across multiple zones
Solution Approach 2:
The system performs preliminary heating or cooling adjustments based on predicted temperature distribution requirements before the actual processing begins. By pre-adjusting heater power levels according to the state-space model predictions, the system reduces the time required to reach stable temperature distribution when processing starts
3Manufacturing precision
If the size of each controllable area is reduced to increase the number of areas, then the temperature distribution control precision is improved, but the reliability of providing heater and temperature sensor in each area deteriorates
Solution Approach 1:
The patent replaces physical temperature sensors with resistance value measurements as a substitute indicator. This copying method allows temperature monitoring in reduced-size zones without the reliability issues associated with placing physical sensors in every small area
Solution Approach 2:
The heater serves its own temperature monitoring function through resistance measurement, eliminating the need for separate temperature sensing components in each zone. This self-service approach ensures reliable temperature control even in zones where placing dedicated sensors would be unreliable
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
The method enables rapid stabilization of temperature distribution across zones, improving processing uniformity on substrates by ensuring precise temperature control and reducing temperature differences among zones.
Implementation Method 1
a heater HT provided in each zone Z, and the temperature of each zone Z is individually controllable
Implementation Method 2
there is known a technique that estimates the temperature of each area from the relationship between the resistance value of the heater provided in each area of the stage where temperature is controllable independently and the temperature
Implementation Method 3
for each of the plurality of zones, a temperature of another zone that is weight-averaged is specified by a weighting coefficient determined according to a magnitude of heat transfer with the another zone
Data Source
AI summary
A model-based control method includes: (a) acquiring temperature control data including temperature data of each of a plurality of zones of a temperature control member provided in a processing apparatus, temperature of each of the plurality of zones being individually controllable; (b) for each zone, specifying a temperature of another zone that is weight-averaged by a weighting coefficient determined according to a magnitude of heat transfer with the another zone; (c) for each zone, specifying a parameter of a state-space model of multi-input/single-output using the specified temperature of the another zone and the temperature control data; (d) creating a state-space model of multi-input/multi-output by assigning the specified parameter of the state-space model of multi-input/single-output to each element of the state-space model of multi-input/multi-output; and (e) controlling the temperature of each of the plurality of zones of the temperature control member using the state-space model of multi-input/multi-output.