Plasma Wafer Table Temperature Correction Across Wide Refrigerant Ranges
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in accurately controlling the temperature of semiconductor wafers within a wide range, from below zero to near 100°C, due to significant changes in heat absorption by the refrigerant, leading to increased detection errors and reduced processing efficiency.
Innovation Solution
The apparatus includes a processing chamber with a sample table equipped with a metal base member containing a refrigerant flow path and temperature sensors. A controller uses pre-measured linear functions to correct temperature detection errors, allowing for precise temperature control across multiple continuous temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the temperature of the refrigerant is adjusted to control the sample table temperature within a wide range, then the temperature control range is improved, but the detection accuracy deteriorates due to significant changes in heat absorption by the refrigerant
Solution Approach 1:
The patent applies parameter changes by measuring the actual temperature of the sample table at multiple different refrigerant temperatures to determine how detection error varies with temperature. This allows the system to adapt the detection parameters (error values) based on the operating conditions, resolving the contradiction between wide temperature control range and detection accuracy
Solution Approach 2:
The patent implements feedback by using the measured detection errors at different refrigerant temperatures to correct the temperature readings. The controller stores the relationship between refrigerant temperature and detection error, and uses this feedback information to compensate for accuracy degradation, maintaining precise temperature control across the wide temperature range
2Reliability
If the temperature of the sample table is controlled with high accuracy across a wide range, then the processing yield is improved, but the system complexity increases due to multiple temperature sensors and correction mechanisms
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing the detection errors at various refrigerant temperatures before actual processing. This advance preparation creates a lookup table or correction database that simplifies the real-time control operation, reducing the complexity during processing while maintaining high accuracy and reliability
Solution Approach 2:
The patent changes the parameter being measured from direct temperature to temperature detection error, which varies more predictably with refrigerant temperature. This parameter transformation simplifies the control logic and reduces system complexity while improving reliability through more accurate temperature control
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 solution improves temperature detection accuracy, enhancing the yield of semiconductor wafer processing by effectively managing temperature variations and reducing detection errors.
Implementation Method 1
a refrigerant flow path through which a temperature-adjusted refrigerant flows
Implementation Method 2
when the temperature of the refrigerant increases or decreases... the amount of heat from the heater, which is absorbed by the refrigerant
Implementation Method 3
at least one temperature sensor that is arranged between the refrigerant flow path and an upper surface of the base member and is configured to detect a temperature
Implementation Method 4
a heater for generating heat when a current is supplied
Data Source
AI summary
A plasma processing apparatus having an improved yield includes a metal base member having a disk shape or a cylindrical shape arranged inside a sample table; a refrigerant flow path arranged multiple times in a concentrical shape around a center of the base member; at least one temperature sensor; and a controller configured to detect a temperature of the base member or the wafer using the temperature sensor. The controller is configured to detect the temperature of the base member or the wafer based on one of a plurality of linear functions indicating a relation between an error and a set temperature of the refrigerant, and the linear functions are different corresponding to regions of a plurality of continuous temperature ranges within an adjustable temperature range of the refrigerant, and the plurality of linear functions include the same coefficient and have a point where the error is 0.