Chemical Liquid Feeding Device Staggered Pump Timing
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Solution Overview
Problem
Conventional chemical liquid feeding devices in semiconductor fabrication processes face limitations in increasing flow rate, are difficult to clean and replace safely, and suffer from pulsation issues leading to vibrations and irregular discharge pressure.
Innovation Solution
A chemical liquid feeding device with three or more pumps arranged in a line, each with distinct suction and discharge stroke times, connected by suction and discharge pipes oriented along the gravity direction to prevent liquid residue, and controlled by a sequence to minimize pulsation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two bellows pumps are installed facing each other with opposite suction and discharge timing, then uniform chemical liquid feeding is achieved, but the flow rate cannot be increased due to structural limitations
Solution Approach 1:
The patent divides the pumping system into three separate bellows pumps (210, 212, 214) arranged in parallel, each handling a portion of the total flow. This segmentation allows the system to achieve higher flow rates while maintaining the uniform feeding characteristic through coordinated operation of multiple smaller pumps rather than relying on a single large pump.
Solution Approach 2:
The patent combines three bellows pumps working in parallel with staggered suction and discharge timing. By merging the output of multiple pumps into a common discharge line, the system achieves both increased flow rate and uniform feeding, resolving the contradiction between productivity and device complexity.
2Ease of operation
If bellows pumps are installed horizontally to achieve compact structure, then chemical liquid remains in the pump during operation, but pump replacement becomes dangerous due to chemical exposure risk
Solution Approach 1:
The patent inverts the conventional horizontal installation orientation and installs the bellows pumps vertically with the discharge port at the bottom. This inversion allows gravitational drainage of chemical liquid from the pump body, significantly reducing residue and making pump replacement safer by minimizing chemical exposure risk to operators.
Solution Approach 2:
By positioning the discharge port at the lowest point of the pump structure, the patent creates a gravitational equipotential path for chemical liquid to drain completely from the pump body. This ensures that no chemical liquid remains trapped in the pump, eliminating the hazard associated with pump replacement.
3Productivity
If fine abrasive is contained in chemical liquid for wafer cleaning, then cleaning effectiveness is improved, but pump components are abraded reducing pump life
Solution Approach 1:
The patent extracts the harmful abrasive particles from the pump system by implementing a vertical drainage configuration that allows complete evacuation of chemical liquid containing abrasive. By taking out the abrasive-laden liquid from the pump body, the system protects internal components from abrasion while maintaining the cleaning function in the wafer processing.
Solution Approach 2:
The patent implements preliminary drainage action by designing the pump structure to automatically drain chemical liquid containing abrasive before pump replacement or maintenance. This preliminary removal of abrasive-containing liquid prevents subsequent abrasion damage to pump components during handling and replacement operations.
4Productivity
If long conversion period between maximum discharge points of pumps is used to achieve uniform feeding, then pulsation is reduced, but pressure difference becomes very large during transition
Solution Approach 1:
The patent segments the discharge function across three pumps with staggered timing, creating multiple overlapping discharge phases. This segmentation smooths the pressure transitions by distributing the load across multiple pumps rather than relying on a single long conversion period between two pumps, thereby reducing peak-to-valley pressure differences while maintaining feeding uniformity.
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 enables uniform, pulsation-free feeding of chemical liquids with regular supply pressure, reducing the risk of pump damage and extending pump life by preventing liquid residue and minimizing vibrations.
Implementation Method 1
a suction pipe for integrally connecting suction ports of the pumps and a discharge pipe for integrally connecting discharge ports of the pumps, wherein the suction port and the discharge port are disposed along a gravity direction so as not to remain and to discharge all chemical liquid flowing in an inside of the pump
Data Source
AI summary
A chemical liquid feeding device for feeding chemical liquid used in a semiconductor fabrication process. The device includes three or more pumps arranged in a line. Each pump has different time points of suction stroke and discharge stroke so that the chemical liquid can be fed uniformly without pulsation.