Fan Control Sequences for Semiconductor Facility Pressure Management
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Solution Overview
Problem
Semiconductor manufacturing facilities face challenges in maintaining optimal pressure and air flow to prevent contamination and particle discharge, as existing methods struggle to effectively manage pressure differences and air flow adjustments across apparatuses.
Innovation Solution
A method involving differential pressure sensors to measure and classify fan output changes, generate regulation performance indices, and adjust fan rotation speeds to control pressure conditions within the facility, grouping fans into subgroups for targeted control sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If pressure inside the facility is maintained higher than outside to prevent contamination, then contamination prevention is improved, but particle discharge control becomes difficult
Solution Approach 1:
The facility is divided into multiple pressure zones with different pressure levels. Each zone is independently controlled with its own fans and pressure management, allowing simultaneous prevention of external contamination while controlling internal particle discharge to specific zones.
Solution Approach 2:
Different pressure conditions are applied to different locations within the facility. Critical areas requiring contamination protection maintain positive pressure, while other areas are managed separately to control particle discharge, optimizing both objectives in their respective locations.
2Ease of operation
If air flow is adjusted by keeping pressure difference between apparatuses constant, then air flow control is simplified, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The pressure difference between apparatuses is made dynamic rather than constant. The control system continuously adjusts pressure differences based on operating conditions, fan status, and process requirements, enabling adaptability while maintaining effective air flow control through active management.
Solution Approach 2:
Pressure sensors continuously monitor pressure conditions throughout the facility and provide feedback to the control system. This feedback enables real-time adjustment of fan speeds and pressure management to maintain optimal air flow patterns under varying operating conditions.
3Speed
If multiple fans are operated simultaneously to adjust air flow, then air flow adjustment speed is improved, but pressure control precision deteriorates
Solution Approach 1:
Fans are pre-configured into groups with predetermined control sequences. When pressure adjustment is needed, the control system activates fans in a specific sequence rather than simultaneously, allowing progressive pressure changes that maintain precision while achieving timely response through pre-planned activation patterns.
Solution Approach 2:
Fan operation is implemented in periodic cycles rather than continuous simultaneous operation. Fans are activated in sequences with timed intervals, allowing pressure to stabilize at intermediate levels between adjustments, which maintains control precision while achieving overall fast response through efficient cycling.
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 approach enhances the ability to maintain optimal pressure and air flow within the facility, reducing contamination risks and improving operational efficiency by intuitively determining pressure changes and adjusting fan speeds to maintain operating pressure ranges.
Implementation Method 1
first, second, and third differential pressure sensors in the semiconductor manufacturing facility
Implementation Method 2
a plurality of fans in the semiconductor manufacturing facility
Data Source
AI summary
A method for controlling a semiconductor manufacturing facility includes measuring output change amounts of differential pressure sensors in the facility when pressure conditions change by a number of fans. The fans are then classified into different groups and subgroups and control sequences of the subgroups are determined based on the change amounts. Difference values are then calculated, and a control signal is generated to adjust the rotation speed of the fans.