Substrate Floating Device for Contamination Prevention
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Solution Overview
Problem
Conventional substrate processing apparatuses face challenges in preventing contamination of the bottom surface of substrates due to mist-like processing liquids and particles, as the substrate is held slightly floated from the support base, limiting the proximity between the substrate and the base and requiring complex lift pin mechanisms that can damage the substrate.
Innovation Solution
A substrate processing apparatus that uses a substrate floating device with gas ejection outlets to float the substrate horizontally, allowing it to be positioned closer to the base without contact, using an upward/downward driver to move the substrate to a transfer position above the processing area, thereby preventing contamination and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the substrate is held slightly floated from the support base using conventional substrate support pins, then the bottom surface of the substrate is protected against damage and contamination, but the gap between the substrate and support base becomes too large, allowing mist-like processing liquid and particles to flow beneath and contaminate the bottom surface
Solution Approach 1:
The patent applies pneumatic principles by using gas ejection outlets on the support base to eject gas upward, creating a gas cushion that floats and supports the substrate. This pneumatic support system enables the substrate to be positioned very close to the support base without physical contact, preventing contamination from processing liquids and particles while eliminating the need for mechanical contact points that would create gaps.
Solution Approach 2:
The patent replaces the conventional mechanical substrate support pin system with a gas cushion-based support system. Instead of using mechanical pins that physically contact and hold the substrate at a fixed distance, the system uses ejected gas to create a non-contacting support mechanism, allowing the substrate to float horizontally at a minimal distance from the support base.
2Object-affected harmful factors
If lift pins are disposed on the support base to reduce the gap between substrate and support base, then the bottom surface contamination is prevented, but the lift pins contact and may damage or contaminate the bottom surface, and the driving mechanism becomes complex creating more particles
Solution Approach 1:
The patent replaces complex mechanical lift pin mechanisms with a pneumatic gas cushion system. Gas is ejected through outlets on the support base to create a floating support for the substrate, eliminating the need for mechanical contact and complex driving mechanisms while maintaining minimal gap distance to prevent contamination.
Solution Approach 2:
The patent introduces gas as an intermediary medium between the support base and the substrate. This gas cushion acts as a mediator that provides support and reduces the gap distance without requiring direct mechanical contact, thereby avoiding damage and contamination that would occur with lift pins while simplifying the overall mechanism.
3Object-affected harmful factors
If the substrate is positioned closer to the support base to prevent contamination, then the bottom surface is protected, but the transportation arm cannot be inserted into the space between substrate and support base to load and unload substrates
Solution Approach 1:
The patent employs dynamic positioning where the substrate floatation height can be adjusted. The gas ejection system allows the substrate to be positioned at different vertical levels, enabling the transportation arm to access the substrate for loading and unloading operations while maintaining the ability to reduce the gap distance when contamination prevention is the priority.
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
Enables precise positioning of the substrate at the processing position close to the base without contact, preventing contamination and damage, while simplifying the structure and reducing particle generation during processing.
Implementation Method 1
a substrate floating device which includes a substrate floating head and which ejects out gas toward the bottom surface of the substrate at an ejection outlet which is formed in a support surface of the substrate floating head, thereby floating up the substrate approximately horizontally
Data Source
AI summary
As a substrate transportation robot transports an unprocessed substrate W to a substrate transfer position P1, inert gas ejected from a substrate floating head 71 toward the bottom surface of the substrate W floats up the unprocessed substrate W. Driven by an actuator 74, the substrate floating head 71 floating up the unprocessed substrate W then moves down. Upon arrival of the unprocessed substrate W at a substrate processing position P3, a bottom rim portion of the substrate W engages with support pins 3, and as the substrate floating head 71 further moves down, the unprocessed substrate W is transferred to and mounted on the support pins 3. The substrate W is thus positioned at the substrate processing position P3, whereby the bottom rim portion of the substrate W and an opposing surface 5b of a spin base 5 are positioned close to each other and opposed against each other.