Liquid Supply Unit Pressure Control to Prevent Boiling Particles
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Solution Overview
Problem
In semiconductor manufacturing, the liquid supply units for substrate cleaning often cause boiling issues and particle formation due to inadequate temperature control at the liquid contact surface, leading to contamination in subsequent processes.
Innovation Solution
A liquid supply unit with a controller that manages gas supply, pressure, and temperature to prevent boiling, featuring a circulation line with a pressure regulator and temperature sensors to maintain the liquid below its boiling point, and a gas control valve to maintain internal pressure while exhausting when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater heats the liquid without considering the temperature at the contact surface, then the liquid can be heated to the predetermined temperature, but the liquid at the contact surface is heated to form bubbles which create particles on the substrate
Solution Approach 1:
The patent employs feedback control by measuring the temperature at the heater contact surface with a temperature sensor and adjusting the heater power accordingly. The controller reduces heater power when the contact surface temperature approaches the liquid's boiling point, preventing bubble formation while maintaining overall liquid temperature control
Solution Approach 2:
The patent changes the control parameter from bulk liquid temperature to contact surface temperature. By monitoring and controlling the temperature at the heater-liquid interface rather than the bulk liquid temperature, the system prevents localized overheating and bubble formation while still achieving the required liquid temperature for the cleaning process
2Object-generated harmful factors
If the circulation line is pressurized while liquid is supplied to the inner space, then boiling is prevented and particle generation is minimized, but the device complexity increases due to additional pressure control components
Solution Approach 1:
The circulation line serves multiple functions: it circulates liquid for heating, maintains system pressure to prevent boiling, and enables temperature control. By integrating pressure maintenance into the existing circulation system rather than adding a separate pressure control system, the patent reduces overall device complexity while achieving the desired effect of preventing particle formation
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
Prevents boiling and minimizes particle generation, ensuring a clean substrate surface by effectively controlling temperature and pressure within the liquid supply unit.
Implementation Method 1
the controller is configured to control the liquid supply unit so that the circulation line is pressurized while the liquid is supplied to the inner space
Implementation Method 2
a first heater for heating the liquid within the circulation line
Implementation Method 3
the circulation line comprises: a first pump
Implementation Method 4
a pressure providing member provided at a downstream of the first heater, wherein a pressure of the liquid required to pass through the pressure providing member is provided higher than a pressure of the liquid required to pass through the first heater
Data Source
AI summary
A liquid supply unit includes a tank having an inner space for storing the liquid, an inlet line for supplying the liquid from the liquid supply source to the inner space and having an inlet valve installed thereon, an outlet line for supplying the liquid from the tank to a nozzle or for recollecting the liquid to the tank and having an outlet valve installed thereon, a gas supply line for supplying a gas to the inner space and having a gas control valve installed thereon, an exhaust line for exhausting the inner space and having an exhaust valve installed thereon, a circulation line for circulating the liquid stored in the inner space, and a controller controlling the liquid supply unit so that the circulation line is pressurized while the liquid is supplied to the inner space.