Equipment front-end module and method for controlling humidity in equipment front-end module
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Solution Overview
Problem
The equipment front-end module (EFEM) in semiconductor manufacturing facilities faces challenges in maintaining controlled humidity levels, leading to substrate contamination and particle formation due to external moisture infiltration and pressure changes during substrate transfer.
Innovation Solution
An EFEM equipped with a humidity control device that includes a fan filter unit, a gas supply unit, differential pressure and humidity sensors, and a control unit to regulate the rotation speed of the fan filter unit and the gas flow rate based on sensor data, ensuring optimal humidity and differential pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the load port module is opened to transfer a substrate, then substrate transfer is enabled, but the sudden change in pressure inside the equipment front-end module causes an increase in humidity
Solution Approach 1:
The differential pressure control system performs preliminary action by detecting pressure changes before they significantly impact humidity. The control unit receives differential pressure information and adjusts the fan filter unit and gas supply unit proactively to maintain pressure balance, preventing moisture infiltration before it occurs
Solution Approach 2:
The system implements feedback control by continuously monitoring differential pressure through the sensor and adjusting the fan filter unit rotation speed and gas supply flow rate based on the measured pressure difference. This closed-loop feedback ensures that humidity is controlled by maintaining proper pressure differential
2Reliability
If humidity control devices are added to the EFEM, then humidity control capability is improved, but the device complexity increases
Solution Approach 1:
The fan filter unit serves multiple functions: it provides gas circulation, controls differential pressure, and prevents moisture infiltration. The gas supply unit similarly performs both pressure control and humidity prevention functions, reducing the need for separate dedicated components for each function
Solution Approach 2:
The system controls humidity by changing operational parameters (rotation speed of fan filter unit, flow rate of gas supply) rather than adding complex structural components. The control unit adjusts these parameters dynamically based on differential pressure and humidity sensor feedback
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 effectively maintains low humidity levels within the EFEM, preventing substrate contamination and particle formation, while rapidly adjusting to changes in differential pressure caused by load port operations, thereby ensuring substrate cleanliness and process reliability.
Implementation Method 1
a fan filter unit, with one end connected to the other end of a circulation line that is connected to an exhaust port of the buffer unit, configured to introduce gas supplied from the circulation line into the transfer frame
Implementation Method 2
a differential pressure sensor installed on a portion of the transfer frame and configured to measure a differential pressure, which is a value obtained by subtracting an external pressure from an internal pressure of the transfer frame
Implementation Method 3
a humidity sensor installed on a portion of the transfer frame and configured to measure humidity inside the transfer frame
Implementation Method 4
a gas supply unit configured to supply gas into the transfer frame
Implementation Method 5
a control unit configured to control a rotation speed of the fan filter unit and a flow rate of gas supplied into the transfer frame through the gas supply unit, based on information received from the humidity sensor and the differential pressure sensor
Data Source
AI summary
An equipment front-end module according to an aspect of the present invention includes: a load port; a transfer frame; a buffer unit; a fan filter unit; a gas supply unit; a differential pressure sensor installed on a portion of the transfer frame and configured to measure a differential pressure, which is a value obtained by subtracting an external pressure from an internal pressure of the transfer frame; a humidity sensor installed on a portion of the transfer frame and configured to measure humidity inside the transfer frame; and a control unit configured to control a rotation speed of the fan filter unit and a flow rate of gas supplied into the transfer frame through the gas supply unit, based on information received from the humidity sensor and the differential pressure sensor.