Substrate Liquid Nozzle Suck-Back Control for Droplet Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The spin-type substrate treating apparatus experiences issues with static electricity causing chemical droplets to form at the nozzle end, leading to concentration phenomena and annular shape defects, as well as pipe contamination due to fumes generated during the process, particularly with low surface tension solutions.
Innovation Solution
A liquid treating apparatus with a valve assembly that includes a cut-off valve and a suck-back valve, where the suck-back speed is controlled to 10 mm/s or lower, and air pressure is adjusted to prevent chemical dripping, minimizing pipe contamination and static electricity effects by optimizing the flow velocity and pressure of air used in the suck-back operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spin-type substrate treating apparatus supplies chemical to the substrate during rotation, then substrate cleaning and etching are achieved, but static electricity is generated causing chemical droplets to form at the nozzle end
Solution Approach 1:
The suck-back valve performs a preliminary action by sucking back the chemical from the nozzle end before the static electricity can cause droplet formation. This preventive measure eliminates the harmful effect before it manifests, resolving the contradiction between maintaining treatment efficiency and preventing static electricity-related defects
Solution Approach 2:
The invention converts the harmful static electricity effect into a benefit by using the same electrostatic force to drive the suck-back valve. The charged particles in the chemical flow are utilized to activate the suck-back mechanism, turning the harmful static electricity into the driving force that prevents droplet formation
2Speed
If the suck-back valve operates at high speed to quickly remove chemical, then pipe emptying is efficient, but pipe contamination occurs due to fumes generated during the process
Solution Approach 1:
The invention changes the speed parameter of the suck-back operation, controlling it to operate at lower speeds rather than high speeds. This parameter adjustment reduces the generation of fumes during the suck-back process, thereby minimizing pipe contamination while still achieving effective pipe emptying
Solution Approach 2:
The suck-back valve operates periodically rather than continuously, with controlled intervals between operations. This periodic action allows for reduced-speed operations that minimize fume generation, while still achieving the necessary pipe emptying effect over time
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 improves substrate treating efficiency, controls abnormal radiation phenomena, and minimizes pipe contamination by effectively managing static electricity and fumes, ensuring stable chemical delivery and preventing defects associated with low surface tension solutions.
Implementation Method 1
a suck-back valve provided adjacent to an end of the cut-off valve and configured to suck-back the liquid of the nozzle
Implementation Method 2
supplies a chemical (e.g., an etching liquid, a cleaning liquid, or a rising liquid) to the substrate through a liquid supply nozzle while rotating the substrate to thereby clean the substrate by spreading the chemical on a top surface of the substrate by a centrifugal force
Implementation Method 3
a first flow velocity controller configured to adjust a flow velocity of an air introduced into or outflowed from the cut-off valve; and a second flow velocity controller configured to adjust a flow velocity of an air introduced into or outflowed from the suck-back valve
Data Source
AI summary
The inventive concept provides a liquid treating apparatus. The liquid treating apparatus includes a spin chuck configured to support and rotate a substrate; and a liquid supply unit configured to supply a liquid to the substrate, and wherein the liquid supply unit includes: a first nozzle connected to a first flow path pipe and configured to discharge a first liquid to the substrate; a first valve assembly including a first cut-off valve for cutting-off a flow of the first liquid within the first flow path pipe and a first suck-back valve for sucking-back the first liquid, and installed at the first flow pipe; a second nozzle connected to a second flow path pipe and configured to discharge a second liquid to the substrate; a second valve assembly including a second cut-off valve for cutting-off a flow of the second liquid within the second flow path pipe and a second suck-back valve for sucking-back the second liquid, and installed at the second flow pipe path; a first flow velocity controller configured to adjust an air flow velocity of an air introduced into or outflowed from the first suck-back valve; and a second flow velocity controller configured to adjust an air flow velocity of an air introduced into or outflowed from the second suck-back valve, and wherein a first speed of a suck-back speed provided by the first valve assembly is slower than a second suck-back speed provided by the second valve assembly, and a surface tension of the first liquid is lower than a surface tension of the second liquid.