Electrostatic Chuck Heater Control Using Resistance Temperature Estimation
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to achieve precise and uniform substrate treatment using plasma processes, particularly in controlling the temperature of multiple heaters in an electrostatic chuck, where installing numerous temperature measurement sensors is difficult due to structural constraints, leading to the use of open-loop systems with increased costs and inefficiencies.
Innovation Solution
A control method involving a support unit with a first and second heater, where the temperature of the first heater is measured, and a compensation factor is calculated based on the resistance of the second heater to estimate its temperature, allowing for accurate output adjustment of the second heater, enabling efficient and uniform substrate treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of temperature measurement sensors are installed in the electrostatic chuck to implement closed-loop control, then temperature control precision is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent introduces a mediator (reference heater with known characteristics) that indirectly provides temperature information for multiple heating regions. Instead of installing sensors in each heating region, the reference heater serves as an intermediary whose temperature measurement can be used to infer temperatures in other regions through calculated relationships, thereby reducing sensor quantity and structural complexity
Solution Approach 2:
The patent creates a simplified copy (reference heater) that replicates the thermal characteristics of the heating regions. This reference heater copy allows temperature estimation for multiple regions without requiring direct measurement in each region, reducing the need for numerous sensors and simplifying the overall structure
2Device complexity
If open-loop control is used to avoid installing multiple temperature sensors, then device complexity is reduced, but temperature control precision and uniformity deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where temperature measurement from the reference heater is used to calculate and adjust power distribution to multiple heating regions. This feedback loop enables closed-loop control without requiring sensors in each heating region, thereby maintaining temperature control precision while avoiding the complexity of installing multiple sensors
Solution Approach 2:
The patent changes the control parameter from direct temperature measurement in each heating region to indirect temperature estimation based on reference heater measurement and calculated relationships. This parameter transformation allows accurate temperature control to be achieved with fewer sensors, improving manufacturing precision without proportionally increasing device complexity
3Manufacturing precision
If multiple temperature measurement sensors are installed to achieve accurate temperature control, then substrate treatment uniformity is improved, but installation difficulty and cost increase
Solution Approach 1:
The reference heater serves multiple functions: it acts as both a heating element and a temperature reference for multiple heating regions. This multi-functional design allows accurate temperature control across multiple regions without requiring separate sensors for each region, thereby improving substrate treatment uniformity while simplifying installation and reducing costs
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 method allows for efficient substrate treatment with improved uniformity and precise temperature control of heaters, considering installation position and structural influences, while reducing the need for multiple sensors and associated costs.
Implementation Method 1
a temperature of a first heater (231) is measured
Implementation Method 2
a resistance measurement sensor (242) for measuring a resistance of the second heater (241)
Implementation Method 3
a first heater (231) which is installed on the support plate (210)
Implementation Method 4
a second heater (241) which is installed on the support plate (210) at a height different from that of the first heater (231)
Implementation Method 5
A plasma substrate treating apparatus which uses the plasma to process a substrate such as a wafer
Data Source
AI summary
The inventive concept provides a control method for controlling a support unit. The support unit includes a support plate on which a substrate is placed; a first heater installed on the support plate; and a second heater installed on the support plate at a different height from the first heater, and the control method includes: determining whether a temperature of the first heater has reached a normal state after the temperature of the first heater varies; measuring a resistance of the second heater after the temperature of the first heater has reached the normal state; and calculating a compensation factor for estimating a temperature of the second heater based on the resistance of the second heater which has been measured.