Substrate Rinsing Electrostatic Charge Suppression
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Solution Overview
Problem
The electrostatic charging of substrates with dielectric and metallic films during the rinsing process using ultrapure water leads to reattachment of particles, potential device destruction, and poor adhesion issues, particularly with copper interconnects, making it difficult to eliminate static electricity from dielectric films like TEOS.
Innovation Solution
A substrate processing method involving simultaneous irradiation of soft X-rays and supply of pure water, where the X-ray irradiation is stopped after the water supply is ceased, effectively suppressing electrostatic charges during the rinsing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ultrapure water with high specific resistance value is supplied onto the rotating substrate for rinsing, then the rinsing effect is improved, but the substrate surface becomes electrostatically charged
Solution Approach 1:
A conductive liquid is introduced as an intermediary substance between the ultrapure water and the substrate surface. The conductive liquid forms a film on the substrate that allows charge dissipation, while the ultrapure water rinses through or alongside this conductive layer, maintaining both rinsing quality and electrostatic control
Solution Approach 2:
The specific resistance value of the liquid film in contact with the substrate is changed by using a conductive liquid with lower resistance. This parameter change enables charge dissipation while the rinsing process maintains its effectiveness through the conductive liquid's properties
2Object-affected harmful factors
If soft X-ray irradiation is applied to remove electrostatic charge from dielectric film, then the static electricity is removed, but the process becomes extremely difficult for TEOS films and requires additional equipment
Solution Approach 1:
The mechanical/electrical process of soft X-ray irradiation is replaced with a chemical/electrical process using conductive liquid. The conductive liquid provides a simpler, more direct path for charge dissipation through ionic conduction and electrical contact, eliminating the need for complex X-ray generation and control systems
Solution Approach 2:
A disposable or easily replaceable conductive liquid is used instead of expensive and complex X-ray equipment. The conductive liquid can be supplied continuously or replaced easily, providing a cost-effective and simplified solution for charge removal
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 prevents electrostatic charging of substrates during rinsing, reducing the risk of particle reattachment and device damage, and maintaining low surface potential, thereby enhancing the reliability of semiconductor devices.
Implementation Method 1
irradiation of a surface of the substrate with soft X-rays
Data Source
AI summary
A substrate processing method includes rotating a substrate about a central axis thereof; starting irradiation of a surface of the substrate with soft X-rays; simultaneously with or after starting the irradiation of the surface of the substrate with the soft X-rays, starting supply of pure water onto the surface of the substrate; stopping the supply of the pure water onto the surface of the substrate; and then stopping the irradiation of the surface of the substrate with the soft X-rays.