Electrostatic Chuck Substrate Processing Pressure Control
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Solution Overview
Problem
In substrate processing, temperature changes cause particles to occur due to differences in thermal expansion coefficients between the substrate and the electrostatic chuck, and existing methods to reduce attraction force by allowing gas flow lead to increased gas leakage and particle adsorption.
Innovation Solution
A substrate processing method that controls the pressure and voltage to minimize particle adsorption by changing the pressure of the heat transfer gas and applied voltage in a controlled manner, while maintaining the susceptor in a grounded state to reduce discharge risk and stabilize the temperature of the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If gas flow is allowed between the substrate and electrostatic chuck to reduce attraction force, then particle generation is reduced, but gas leakage increases and particle adsorption worsens
Solution Approach 1:
The patent changes the pressure parameter of the heat transfer gas from atmospheric pressure to reduced pressure (vacuum state). This parameter change allows the gas to flow between the substrate and electrostatic chuck, reducing attraction force and particle generation, while the reduced pressure environment prevents particle adsorption and gas leakage issues that would occur at atmospheric pressure
Solution Approach 2:
The patent creates a vacuum/inert environment in the processing chamber by maintaining reduced pressure. This inert environment prevents particles from being adsorbed onto the substrate while still allowing controlled gas flow to reduce the attraction force between the substrate and electrostatic chuck, thereby resolving the contradiction between reducing particle generation and preventing particle adsorption
2Stability of the object's composition
If voltage is applied to electrostatic chuck to hold substrate, then substrate positioning is stable, but thermal expansion differences cause scratches
Solution Approach 1:
The patent changes the pressure parameter of the heat transfer gas to reduced pressure, which modifies the thermal conduction characteristics between the substrate and electrostatic chuck. This parameter change reduces thermal stress and thermal expansion differences, preventing scratches while maintaining stable substrate positioning through electrostatic attraction
Solution Approach 2:
The patent introduces heat transfer gas as an intermediary medium between the substrate and electrostatic chuck. This gas layer acts as a thermal and mechanical buffer, reducing direct contact and thermal stress that cause scratches, while still allowing electrostatic forces to maintain stable substrate positioning
3Temperature
If heat transfer gas is supplied at atmospheric pressure, then temperature control is effective, but substrate attraction force increases causing particle generation
Solution Approach 1:
The patent changes the pressure parameter of the heat transfer gas from atmospheric pressure to reduced pressure. This parameter change reduces the attraction force between substrate and electrostatic chuck, preventing particle generation, while still maintaining effective temperature control through the heat transfer gas in the vacuum state
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 effectively suppresses particle adsorption and improves temperature control, reducing the occurrence of scratches and gas leakage, thereby enhancing the processing quality.
Implementation Method 1
an electrostatic chuck which is capable of changing the temperature and which electrostatically attracts the substrate according to applied voltage
Implementation Method 2
a gas supply unit which supplies a gas for heat transfer to a gap between the substrate disposed on the electrostatic chuck and the electrostatic chuck
Data Source
AI summary
A temperature changing method includes changing a pressure of a gas supplied from a gas supply to a gap between the substrate and an electrostatic chuck from a first pressure to a second pressure being lower than the first pressure, changing a voltage applied to the electrostatic chuck from a first voltage to a second voltage being lower than the first voltage, changing a temperature of the electrostatic chuck from a first temperature to a second temperature, electrostatically attracting the substrate by the electrostatic chuck for a time in a state where the gas pressure is the second pressure and the voltage is the second voltage, changing the gas pressure from the second pressure to a third pressure being lower than the first pressure and higher than the second pressure, and changing the voltage from the second voltage to a third voltage being higher than the second voltage.