Substrate Cleaning Layout to Keep the Spin Chuck Clean
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Solution Overview
Problem
Existing substrate cleaning devices face challenges in maintaining the cleanliness of the spin chuck, as contaminants from the cleaning liquid often adhere to its surface, degrading its cleanliness and requiring frequent maintenance.
Innovation Solution
A substrate cleaning device with a second holder that rotates about a vertical axis, allowing the cleaner to contact and clean the substrate's lower-surface center and outer regions, while a mobile base moves to ensure the second holder does not overlap with the substrate during cleaning, and a gas injector is used to prevent liquid splashing and efficiently dry the surface, ensuring the second holder remains clean.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the spin chuck surface is allowed to contact the substrate during cleaning, then cleaning coverage is improved, but cleaning liquid adheres to the spin chuck degrading its cleanliness
Solution Approach 1:
The cleaning process is divided into two distinct phases: a first cleaning process where the spin chuck rotates at high speed without holding the substrate to clean the center region, and a second cleaning process where the spin chuck holds and rotates the substrate to clean the outer region. This segmentation allows the spin chuck surface to remain clean during the first phase while still achieving comprehensive cleaning coverage.
Solution Approach 2:
The first cleaning process is performed as a preliminary action before the second cleaning process. By cleaning the substrate center region first while the spin chuck surface is clean, contaminants are removed before the spin chuck contacts the substrate in the second phase, preventing contaminant transfer to the spin chuck.
2Productivity
If the spin chuck rotates at high speed during cleaning, then cleaning efficiency is improved, but cleaning liquid splashes onto the spin chuck
Solution Approach 1:
The cleaning operation is segmented into two phases with different rotation speeds. During the first cleaning process, the spin chuck rotates at high speed (first rotation speed) to efficiently clean the center region without holding the substrate, minimizing liquid splash adhesion. During the second cleaning process, the spin chuck rotates at lower speed while holding the substrate to clean the outer region.
Solution Approach 2:
The high-speed cleaning of the center region is performed as a preliminary action before the substrate is transferred to the spin chuck. This preliminary high-speed cleaning removes contaminants from areas that would otherwise be difficult to clean, reducing the need for excessive cleaning liquid during subsequent operations and minimizing splash contamination.
3Measurement precision
If the substrate is held by the spin chuck during center region cleaning, then positioning accuracy is improved, but the spin chuck becomes contaminated
Solution Approach 1:
The substrate holding and cleaning functions are segmented across two processes. In the first cleaning process, the substrate is not held by the spin chuck, allowing high-speed rotation for efficient center region cleaning without contamination. In the second cleaning process, the substrate is held by the spin chuck for precise positioning during outer region cleaning, but by this time the spin chuck surface is already clean from the first process.
Solution Approach 2:
The spin chuck surface is preliminarily cleaned or prepared in the first cleaning process before the substrate is transferred to it. This preliminary preparation ensures that when the substrate is subsequently held and positioned by the spin chuck during the second cleaning process, the spin chuck surface remains clean and uncontaminated.
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
The solution effectively prevents contaminants from adhering to the second holder, maintains its cleanliness, and efficiently dries the substrate, reducing maintenance needs and ensuring consistent cleaning performance.
Implementation Method 1
a gas injector that is arranged between the cleaner and the second holder and injects gas toward the substrate
Implementation Method 2
the second holder rotates while not holding the substrate during cleaning of the lower-surface center region
Data Source
AI summary
A cleaner comes into contact with a lower-surface center region of a substrate held by a first holder, so that the lower-surface center region is cleaned. The cleaner comes into contact with a lower-surface outer region of the substrate rotated by a second holder, so that the lower-surface outer region of the substrate is cleaned. During cleaning of the lower-surface center region, the second holder is rotated about a vertical axis while not holding the substrate. Alternatively, during cleaning of the lower-surface center region, the gas injector arranged between the cleaner and the second holder injects gas toward the substrate from a first height spaced apart from the substrate by a predetermined distance. Further, during drying of the lower-surface center region, the gas injector injects gas toward the substrate from a second height closer to the substrate than the first height.