Electrostatic Chuck Charge Elimination via Temperature and Voltage Control
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Solution Overview
Problem
The existing substrate processing methods using electrostatic chucks often result in residual adsorption forces after electric charge elimination, leading to potential substrate cracks or misalignment during lifting, due to the deposition of reaction products with low volume resistivity on the chuck surface.
Innovation Solution
A method involving a substrate processing apparatus with an electrostatic chuck having an insulating member and an electrode, where a heat transfer gas is supplied to the substrate's back surface while eliminating electric charges using plasma, and a sequence of voltage applications to the chuck electrode ensures complete charge elimination, reducing the risk of residual adsorption forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric charge elimination is performed using conventional methods, then the substrate can be lifted from the electrostatic chuck, but residual adsorption forces remain causing substrate cracks or misalignment
Solution Approach 1:
The patent changes the temperature parameter by heating the electrostatic chuck to elevated temperatures (e.g., 100-300°C) during electric charge elimination. This temperature parameter change reduces the volume resistivity of the dielectric layer, enhancing charge elimination efficiency and reducing residual adsorption forces that cause substrate cracks or misalignment
Solution Approach 2:
The patent employs periodic alternating voltage application to the electrostatic chuck during the electric charge elimination process. The voltage is applied in cycles (e.g., positive voltage for a first period, then negative voltage for a second period), which effectively eliminates residual charges from both the substrate and the chuck surface, preventing substrate damage during lifting
2Productivity
If reaction products are deposited on the chuck surface to improve plasma process performance, then etching efficiency increases, but volume resistivity decreases leading to stronger residual adsorption forces
Solution Approach 1:
The patent changes the temperature parameter by heating the electrostatic chuck during electric charge elimination. This temperature increase reduces the volume resistivity of the dielectric layer with deposited reaction products, enabling more effective charge elimination and reducing the harmful adsorption forces while preserving the beneficial etching performance
Solution Approach 2:
The patent converts the harmful effect of low volume resistivity (causing strong adsorption forces) into a beneficial condition by intentionally heating the chuck. The heat treatment reduces volume resistivity to enhance charge elimination, transforming the previously harmful residual charges into a controlled process that prevents substrate damage while maintaining etching efficiency
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 eliminates electric charges from both the chuck and the substrate, preventing cracks and misalignment by maintaining low residual adsorption forces, as demonstrated by reduced dechuck torque and misalignment measurements.
Implementation Method 1
a substrate is adsorbed by an adsorption force generated by applying a voltage to the chuck electrode from a direct voltage source
Implementation Method 2
eliminating electric charges in the substrate using plasma of a process gas
Implementation Method 3
supplying a heat transfer gas having a second gas pressure to a back surface of the substrate while eliminating electric charges in the substrate
Data Source
AI summary
A method of processing a substrate using a substrate processing apparatus that has an electrostatic chuck including an insulating member inside which an electrode is included and provides a plasma process to a substrate mounted on the electrostatic chuck includes a first process of supplying a heat transfer gas having a second gas pressure to a back surface of the substrate while eliminating electric charges in the substrate using plasma of a process gas having a first gas pressure.