Electrostatic Chuck Dechucking With Residual Charge Discharge
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Solution Overview
Problem
Conventional electrostatic chucks face issues with residual charge leading to substrate cracking, inefficient declamping, and particle attraction during substrate separation, particularly in high resistivity substrates like glass or silicon on insulator, impacting yield and quality of integrated circuits.
Innovation Solution
A method involving a substrate support with multiple clamp electrodes and lift pins that actively discharge residual charge using conductive pins or UV light, and a machine learning model to control lift pin movement, ensuring safe and efficient substrate separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrostatic chucks are used to hold substrates during processing, then substrate clamping and processing is achieved, but residual charge remains on the substrate after processing causing cracking, inefficient declamping, and particle attraction
Solution Approach 1:
The patent applies preliminary action by introducing a discharge electrode that actively removes residual charge from the substrate before the substrate is released from the electrostatic chuck. This preliminary discharge action prevents the harmful effects of residual charge (cracking, particle attraction, inefficient declamping) that would otherwise occur after processing, thereby resolving the contradiction between maintaining substrate integrity during processing and eliminating residual charge effects afterward.
2Productivity
If high resistivity substrates like glass or silicon on insulator are processed using conventional electrostatic chucks, then processing is completed, but substrate cracking occurs due to residual charge
Solution Approach 1:
The discharge electrode performs preliminary action by eliminating residual charge from high resistivity substrates before they are released from the electrostatic chuck. This prevents the substrate cracking that would otherwise occur due to trapped residual charge, thereby resolving the contradiction between completing processing and maintaining substrate strength against cracking.
3Productivity
If substrate separation is performed without active discharge, then processing efficiency is maintained, but particle attraction occurs reducing yield and quality
Solution Approach 1:
The discharge electrode performs preliminary action by removing residual charge from the substrate while it is still held by the electrostatic chuck, before the substrate separation occurs. This eliminates particle attraction that would otherwise occur during substrate separation, resolving the contradiction between maintaining separation efficiency and preventing particle attraction that reduces yield and quality.
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
Reduces substrate cracking and particle attraction, enabling defect-free processes and higher quality integrated circuits by effectively eliminating residual charge during substrate separation.
Implementation Method 1
contacting a backside of the substrate with a conductive lift pin
Implementation Method 2
exposing the substrate to ultraviolet light
Implementation Method 3
electrostatically securing a substrate during a process using a plurality of clamp electrodes
Data Source
AI summary
A method including using a plurality of clamp electrodes of a substrate support to electrostatically secure a substrate during a process. The method further includes actively discharging a residual charge from the substrate after completion of the process based on at least one of contacting a backside of the substrate with a conductive lift pin or exposing the substrate to ultraviolet light. The method further includes raising a plurality of lift pins disposed in the substrate support to a first height to lift the substrate off of the substrate support after the discharging of the residual charge.