Substrate Cleaning Sequence to Prevent Particle Reattachment
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Solution Overview
Problem
The high-speed rotation of substrates during cleaning processes reduces the thickness of the liquid film, causing suspended particles to reattach to the substrate.
Innovation Solution
A method involving a liquid treatment operation where a treatment solution is supplied to a rotating substrate to form a liquid film, followed by a gas treatment operation where gas is discharged to remove the upper layer of the liquid film, and finally a liquid film removal operation to remove the lower layer, all while controlling the substrate rotation speed and gas discharge pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is rotated at high speed during cleaning, then particles are removed from the substrate, but the liquid film thickness is reduced causing particles to reattach to the substrate
Solution Approach 1:
The cleaning process is divided into multiple sequential stages: a first cleaning process at high rotation speed to remove particles, followed by a second cleaning process at low rotation speed to prevent reattachment. This segmentation allows each stage to optimize for its specific function without compromise.
Solution Approach 2:
The substrate rotation speed is varied periodically throughout the cleaning process - high speed during the first cleaning stage, then reduced to low speed during the second cleaning stage. This periodic variation in operational parameters enables both particle removal and prevention of reattachment.
2Productivity
If the substrate is rotated at high speed, then cleaning efficiency is improved, but particles suspended in the liquid film reattach to the substrate
Solution Approach 1:
The cleaning process is segmented into two distinct phases: an initial high-speed phase for efficient particle removal, followed by a low-speed phase to maintain liquid film thickness and prevent reattachment. Each phase is optimized for its specific objective.
Solution Approach 2:
The high-speed particle removal is performed as a preliminary action before the low-speed prevention phase. By removing particles first when the liquid film is thin, then maintaining a thicker liquid film at low speed, the system prevents reattachment that would occur if high speed were maintained throughout.
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 the re-adsorption of impurities during cleaning and efficiently removes impurities even at low substrate rotation speeds, ensuring a thorough cleaning process.
Implementation Method 1
a gas treatment operation of discharging gas to the substrate and removing an upper layer of the liquid film from the substrate
Implementation Method 2
supplying a treatment solution to a rotating substrate to form a liquid film on the substrate
Implementation Method 3
a liquid film removal operation of removing a lower layer of the liquid film on the substrate... in which gas may be discharged at a stronger discharge pressure than that in the gas treatment operation
Data Source
AI summary
Disclosed is a method of treating a substrate, the method including: a liquid treatment operation of treating a substrate by supplying a treatment solution to a rotating substrate to form a liquid film on the substrate; after the liquid treatment operation, a gas treatment operation of discharging gas to the substrate and removing an upper layer of the liquid film from the substrate; and after the gas treatment operation, a liquid film removal operation of removing a lower layer in the liquid film on the substrate.