Bladder-Based Fluid Dispense System for Semiconductor Fabrication
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Solution Overview
Problem
In semiconductor fabrication, existing fluid delivery systems face challenges in maintaining high-purity and high-flow rate dispensing of chemicals onto substrates while minimizing defects caused by impurities and gas dissolution, as fine filters reduce fluid flow rates and increase the risk of defects due to reduced flow rates and increased exposure to atmospheric gases.
Innovation Solution
A bladder-based fluid delivery system that uses an elongate bladder for indirect pressure/volume control, minimizing exposure to gases and reducing the number of parts in contact with the process fluid, thereby maintaining high-purity and high-flow rate dispensing without valves downstream of the filter, ensuring a smooth fluid flow path and reducing defects such as gas bubbles, particles, and impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If relatively fine filters are used to filter chemicals immediately prior to dispensing, then purity of dispensed chemicals is improved, but flow rate of the chemicals is reduced
Solution Approach 1:
The system performs preliminary filtration of chemicals before they reach the dispense nozzle, using filters positioned upstream in the fluid pathway. This allows the chemicals to be filtered in advance without requiring fine filters at the point of dispensing, thereby maintaining both high purity and adequate flow rate during actual dispensing operations.
Solution Approach 2:
The fluid delivery system is segmented into multiple sections with different filter stages positioned at different locations along the pathway. Coarser filters are positioned upstream to remove larger particles, while finer filtration occurs in staged sequences, allowing the system to achieve high purity without the flow rate penalties of using only fine filters at the dispensing point.
2Reliability
If pre-filtered chemicals are purchased for use, then defects from impurities are reduced, but cost is increased and defects can develop during transport or use
Solution Approach 1:
The system incorporates self-service filtration capabilities directly within the semiconductor fabrication tool, allowing the chemicals to be filtered on-demand at the point of use rather than relying on externally pre-filtered chemicals. This eliminates the need for expensive pre-filtered chemical purchases and ensures filtration occurs immediately before dispensing, preventing defect development during transport or storage.
3Productivity
If the elongate bladder is contracted to dispense process fluid, then dispense flow rate is increased, but hydraulic fluid pressure must be increased
Solution Approach 1:
The system uses dynamic control of the elongate bladder's contraction and expansion states to regulate dispense flow rate. The bladder can be contracted to a degree that provides the required dispense flow rate while keeping hydraulic pressure within acceptable limits, and can be expanded between dispensing operations to reset the system and prepare for the next dispense cycle.
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 system effectively compensates for filter-lag and maintains high-purity dispensing at specified flow rates, reducing defects and ensuring precise control over fluid dispensing, thereby enhancing the quality of deposited films in semiconductor fabrication.
Implementation Method 1
The elongate bladder is configured to laterally expand and laterally contract within the chamber such that when the elongate bladder contains a volume of process fluid, the volume of process fluid within the elongate bladder is increasable and reducible
Implementation Method 2
The controller is configured to cause process fluid to dispense from the dispense nozzle by selectively contracting the elongate bladder by increasing hydraulic fluid pressure exerted on an exterior surface of the elongate bladder
Implementation Method 3
A process fluid filter is positioned along the process fluid conduit downstream from the process fluid valve and configured to filter process fluid passing through the process fluid conduit
Data Source
AI summary
Techniques herein include a bladder-based dispense system using an elongate bladder configured to selectively expand and contract to assist with dispense actions. This dispense system compensates for filter-lag, which often accompanies fluid filtering for microfabrication. This dispense system also provides a high-purity and high precision dispense unit. A process fluid filter is located downstream from a process fluid source as well as a system valve. Downstream from the process fluid filter there are no valves. Dispense actions can be initiated and stop while the system valve is open by using the elongate bladder. The elongate bladder can be expanded to stop or pause a dispense action, and then be contracted to assist with a dispense action.