Electrostatic Chuck Temperature Control via Staged Voltage
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Solution Overview
Problem
The electrostatic chuck in plasma processing apparatuses faces damage and malfunction due to temperature differences between the base and the chuck main body, leading to peeling, cracking, and warpage, which affects the substrate holding capability.
Innovation Solution
A method involving a dielectric layer and multiple DC power supplies is used to adjust the temperature of the base and chuck main body, applying varying voltages to generate electrostatic attractive forces that fix the chuck main body to the base only when the temperature difference is within a predetermined value, thereby minimizing damage and ensuring proper substrate holding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the chuck main body is fixed to the base with adhesive, then the chuck main body is securely attached to the base, but temperature differences cause peeling, cracking, and warpage of the adhesive
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesive) with an electrostatic attraction mechanism. By applying voltage to the electrode in the chuck main body, electrostatic attractive force is generated between the chuck main body and the base, eliminating the need for adhesive and its associated temperature-related failures.
Solution Approach 2:
The patent changes the bonding mechanism from chemical (adhesive) to physical (electrostatic). By controlling the voltage parameter, the electrostatic attractive force can be adjusted to maintain secure attachment without the peeling, cracking, and warpage issues that occur with adhesive under temperature differences.
2Strength
If voltage is applied to generate electrostatic attractive force, then the chuck main body is attracted to the base, but temperature differences between base and chuck main body still cause damage
Solution Approach 1:
The patent applies voltage to generate electrostatic attractive force before the chuck main body is fully cooled to the operating temperature. This preliminary electrostatic attachment prevents temperature differences from causing damage during the cooling process, and the adhesive-free design eliminates peeling and cracking issues.
3Ease of operation
If multiple DC power supplies are used to control electrostatic forces, then precise control of chuck main body attachment is achieved, but device complexity increases
Solution Approach 1:
The patent divides the electrode into multiple regions (first electrode in substrate mounting region, second and third electrodes in other regions) that can be controlled by different DC power supplies. This segmentation allows precise control of electrostatic forces in different areas, enabling independent control of substrate holding and chuck main body attachment functions.
Solution Approach 2:
The patent makes the electrode system multi-functional by using different regions of the electrode for different purposes: the first electrode controls substrate holding, while the second and third electrodes control chuck main body attachment. This allows a single electrode structure to perform multiple functions, reducing overall system complexity despite using multiple power supplies.
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 effectively reduces temperature differences, preventing damage to the electrostatic chuck and ensuring reliable substrate holding by using electrostatic forces to securely attach the chuck main body to the base, thus enhancing the operational stability of the plasma processing apparatus.
Implementation Method 1
supplying a heat exchange medium for cooling to the base
Implementation Method 2
applying a first voltage from the second DC power supply and a second voltage from the third DC power supply to the second electrode and the third electrode, respectively, to generate an electrostatic attractive force between the dielectric layer and the chuck main body
Implementation Method 3
A DC power supply is electrically connected to the electrode of the chuck main body. A substrate is placed on the chuck main body. In a case where a voltage from the DC power supply is applied to the electrode of the chuck main body, an electrostatic attractive force is generated between the chuck main body and the substrate
Data Source
AI summary
In an embodiment, there is provided a method of operating an electrostatic chuck of a plasma processing apparatus. The electrostatic chuck has a base, a dielectric layer formed on the base, and a chuck main body mounted on the dielectric layer. In the method, a temperature difference between the temperature of the base and the temperature of the chuck main body is reduced in a state in which the chuck main body is attracted to the dielectric layer with a relatively small electrostatic attractive force. In a case where the temperature difference between the temperature of the base and the temperature of the chuck main body becomes equal to or less than a predetermined value, the chuck main body is fixed to the base via the dielectric layer by a relatively large electrostatic attractive force.