Substrate Liquid Processing Apparatus Airflow Abnormality Detection
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Solution Overview
Problem
In substrate liquid processing apparatuses, maintaining the pressure gradient between the housing and the liquid receiving cup is crucial to prevent mist from flowing backward onto the substrate, but existing solutions face challenges in accurately detecting abnormalities in air flow due to difficulties in sensor installation and pressure measurement, especially in multi-stage liquid receiving cups with movable parts.
Innovation Solution
A substrate liquid processing apparatus equipped with a cup exhaust path pressure sensor and a housing pressure sensor, which detects pressure differences to alert when a predetermined threshold is met, allowing for the determination of abnormal air flow conditions and preventing mist from contaminating the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are installed in each exhaust flow path of multi-stage liquid receiving cups, then measurement precision is improved, but device complexity increases due to movable cup bodies making sensor attachment difficult
Solution Approach 1:
The patent extracts the pressure detection function from the movable cup bodies and relocates it to the stationary housing. By installing the pressure sensor in the housing rather than on the movable cups, the system maintains the ability to detect pressure differences while eliminating the complexity of attaching sensors to moving parts. The sensor detects pressure in the housing, and the control unit calculates the pressure difference based on this reading and the known negative pressure in the exhaust path.
Solution Approach 2:
The patent introduces the housing as an intermediary structure that contains the pressure sensor. Instead of directly attaching sensors to the movable cup bodies, the housing serves as a stable intermediary that provides a mounting location for the sensor while still enabling indirect measurement of the pressure differences across the movable components through its structural relationship with the cups and exhaust paths.
2Reliability
If pressure gradient is not maintained, then device complexity is reduced, but reliability deteriorates due to backward flow of mist onto substrate
Solution Approach 1:
The patent implements a feedback control system where the control unit continuously monitors the pressure difference between the housing and the exhaust path using the pressure sensor, and automatically adjusts the exhaust flow rate based on this reading. When the pressure gradient is insufficient and backward flow is detected or predicted, the system increases the exhaust flow rate to restore the appropriate pressure gradient, thereby preventing mist contamination of the substrate.
Solution Approach 2:
The system performs preliminary detection of pressure gradient conditions before backward flow can occur. By continuously monitoring the pressure difference and detecting when it approaches critical thresholds, the system can take preemptive action to adjust exhaust flow rates, preventing the harmful backward flow of mist onto the substrate rather than reacting after contamination has occurred.
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 solution enables accurate detection of air flow abnormalities, enhancing production management efficiency by preventing substrate contamination and simplifying the installation of pressure sensors in complex cup configurations.
Implementation Method 1
a cup exhaust path pressure sensor configured to detect pressure in the cup exhaust path; a housing pressure sensor configured to detect pressure in the housing outside the liquid receiving cup
Implementation Method 2
By forming such a pressure gradient, the atmosphere in a space above the substrate held by the spin chuck (clean gas atmosphere) flows into the liquid receiving cup and is exhausted from the exhaust port of the liquid receiving cup
Implementation Method 3
a spin chuck configured to hold the substrate in a horizontal posture and rotate the substrate around a vertical axis... processing liquid scattered outwardly from the substrate by a centrifugal force
Data Source
AI summary
A substrate liquid processing apparatus includes a substrate holding unit configured to hold and rotate a substrate; a processing liquid nozzle configured to supply a processing liquid to the substrate; a cylindrical liquid receiving cup configured to receive and recover the processing liquid scattered from the substrate; a housing configured to accommodate the substrate holding unit and the liquid receiving cup; a cup exhaust path connected to the liquid receiving cup to exhaust atmosphere inside the liquid receiving cup; a cup exhaust path pressure sensor configured to detect pressure in the cup exhaust path; a housing pressure sensor configured to detect pressure in the housing outside the liquid receiving cup; and a control unit configured to alert when a difference between a value detected by the housing pressure sensor and a value detected by the cup exhaust path pressure sensor is a predetermined determination reference value or less.