Hot Chemical Buffer Tank Venting for Bubble-Free Substrate Cleaning
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Solution Overview
Problem
High temperature chemical solutions like SC1 generate gas bubbles during the cleaning process, leading to malfunction of pumps, heaters, and ultrasonic devices due to dissociation of H2O2 and NH4OH, causing inefficiencies and safety concerns in semiconductor substrate cleaning.
Innovation Solution
A high temperature chemical solution supply system with a buffer tank and needle valve to vent gas bubbles, combined with a method of alternating sonic device operation and chemical delivery to prevent bubble coalescence, ensuring effective cleaning while maintaining device functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature chemical solution is heated to more than 80° C. to effectively remove particles, then cleaning effectiveness is improved, but gas bubbles are generated due to dissociation of H2O2 and NH4OH
Solution Approach 1:
The patent applies preliminary action by pre-heating the chemical solution in a separate heating unit before it enters the cleaning chamber. This prevents gas bubble generation during the cleaning process by ensuring the solution is already at the required temperature (80-95°C) before contact with the substrate, thereby avoiding dissociation of H2O2 and NH4OH during the cleaning operation itself.
Solution Approach 2:
The cleaning system is segmented into separate functional units: a heating unit that prepares the chemical solution at the required temperature, and a cleaning chamber that performs the actual cleaning. This segmentation allows temperature control and chemical solution preparation to occur separately from the cleaning process, preventing gas bubble generation during substrate cleaning while maintaining effective cleaning temperature.
2Productivity
If high temperature chemical solution is subjected to low pressure suction and mechanical agitation, then solution circulation is improved, but gas bubbles are generated due to pressure changes and agitation
Solution Approach 1:
The system performs preliminary heating of the chemical solution in a dedicated heating unit before the solution enters the cleaning chamber. This preliminary temperature preparation ensures that the solution maintains its temperature without requiring aggressive circulation methods that would generate gas bubbles through pressure changes and mechanical agitation during the cleaning process.
3Ease of operation
If gas bubbles are present in the chemical solution during cleaning, then pump and heater function is improved, but cleaning process reliability deteriorates due to miss function of devices
Solution Approach 1:
The heating unit pre-heats the chemical solution to the required temperature (80-95°C) before it enters the cleaning chamber, ensuring that no further heating is needed during cleaning. This preliminary temperature preparation prevents gas bubble generation in the heater during operation, maintaining both ease of operation and reliability.
Solution Approach 2:
The system separates the heating function from the cleaning function into distinct units. The heating unit handles all temperature preparation, while the cleaning chamber focuses solely on substrate cleaning. This segmentation ensures that pumps and heaters operate under stable conditions without gas bubble interference, maintaining reliability while keeping operation simple.
4Manufacturing precision
If ultrasonic device is used to clean substrate simultaneously, then cleaning effectiveness is improved, but gas bubble coalescence occurs on substrate surface
Solution Approach 1:
The chemical solution is pre-heated to the optimal temperature range (80-95°C) in the heating unit before entering the cleaning chamber. This preliminary temperature preparation reduces gas bubble generation during ultrasonic cleaning, preventing bubble coalescence on the substrate surface while maintaining cleaning effectiveness.
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 system effectively reduces gas bubbles in high temperature chemical solutions, preventing device malfunctions and enhancing the cleaning process by maintaining pressure and preventing bubble coalescence, thus improving the efficiency and safety of substrate cleaning.
Implementation Method 1
The needle valve is mounted on the vent line, wherein the needle valve is adjusted to reach a flow rate to vent gas bubbles inside of the high temperature chemical solution out of the buffer tank through the vent line
Implementation Method 2
An inlet of the first pump connects to the solution tank, and an outlet of the first pump connects to the buffer tank. An inlet of the second pump connects to the buffer tank, and an outlet of the second pump connects to a cleaning chamber
Implementation Method 3
The ultra/mega sonic device is positioned adjacent to the substrate and a gap is formed between the substrate and the ultra/mega sonic device
Implementation Method 4
When the SC1 being in such high temperature, chemicals H2O2 and NH4OH in SC1 are easily to be dissociated as gas bubbles of oxygen and ammonia gas
Data Source
AI summary
The present invention provides a high temperature chemical solution supply system for cleaning substrates. The system includes a solution tank, a buffer tank, a first pump and a second pump. The solution tank contains high temperature chemical solution. The buffer tank has a tank body, a vent line and a needle valve. The tank body contains the high temperature chemical solution. An end of the vent line connects to the tank body, and the other end of the vent line connects to the solution tank. The needle valve is mounted on the vent line, wherein the needle valve is adjusted to reach a flow rate to vent gas bubbles inside of the high temperature chemical solution out of the buffer tank through the vent line. An inlet of the first pump connects to the solution tank, and an outlet of the first pump connects to the buffer tank. An inlet of the second pump connects to the buffer tank, and an outlet of the second pump connects to a cleaning chamber in which a substrate is cleaned. The present invention also provides an apparatus including the high temperature chemical solution supply system and an ultra or mega sonic device for cleaning the substrate. The present invention also provides methods for cleaning the substrates.