Inline Dispense Capacitor for Filter-Lag Compensation
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Solution Overview
Problem
In semiconductor fabrication, achieving a specified dispense flow rate while filtering chemicals is challenging due to the use of fine filters, which can slow down the fluid flow and lead to defects on the substrate, as existing systems struggle to maintain the required flow rates during filtration.
Innovation Solution
A dispense capacitor system with a flexible membrane or bladder that selectively adjusts fluid flow and pressure to compensate for slow filtration rates, ensuring a consistent dispense rate by expanding to collect fluid and contracting to expel it, maintaining a linear flow path and preventing backflow through high-purity filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If relatively fine filters are used to filter chemicals immediately prior to dispensing, then manufacturing precision is improved, but productivity deteriorates due to reduced fluid flow rate
Solution Approach 1:
The dispense capacitor accumulates filtered chemical in advance during a charging phase, then rapidly dispenses the accumulated chemical during a dispensing phase. This preliminary filtering and storage action allows the system to overcome the slow flow rate of fine filters by decoupling the filtering operation from the dispensing operation.
Solution Approach 2:
The dispense capacitor acts as an intermediary component between the filter and the dispense nozzle. It receives slowly flowing filtered chemical from the filter, stores it, and then provides rapidly flowing chemical to the nozzle, mediating between the slow filtration process and the fast dispensing requirement.
2Manufacturing precision
If pre-filtered chemistry is purchased for use in coater/developer tools, then manufacturing precision is improved, but reliability deteriorates due to defects developing during transport or use
Solution Approach 1:
The system performs filtering immediately before dispensing rather than relying on pre-filtering done in advance during manufacturing or transport. This preliminary action ensures the chemical is filtered at the exact moment of use, eliminating the risk of defect development during storage and transport.
Solution Approach 2:
The coater/developer tool performs its own filtering operation using an integrated filter and dispense capacitor system, rather than relying on externally pre-filtered chemicals. This self-service approach ensures consistent purity standards are met at the point of dispensing regardless of external supply conditions.
3Productivity
If fluid is pushed through increasingly fine filters at high flow rates, then productivity is improved, but manufacturing precision deteriorates due to insufficient filtration
Solution Approach 1:
The chemical is filtered in advance during a charging phase when high volume accumulation is the goal rather than rapid dispensing. The dispense capacitor collects sufficiently filtered chemical over time, then rapidly dispenses the pre-filtered chemical without requiring the filter to operate at high flow rates during the actual dispensing phase.
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 filters chemicals immediately before dispensing while maintaining a specified flow rate faster than the filtration rate, reducing the likelihood of defects on the substrate by ensuring continuous and uninterrupted fluid flow, thus addressing the challenge of filter-lag and defect creation.
Implementation Method 1
The dispense capacitor includes a flexible membrane or surface that selectively flexes to either increase or decrease fluid flow and/or pressure
Implementation Method 2
to filter chemicals at a semiconductor fabrication tool (for example, coater/developer) immediately prior to dispensing on a substrate
Implementation Method 3
the dispense capacitor defines an approximately linear fluid conduit free from defect-inducing geometry
Data Source
AI summary
A fluid dispensing apparatus is disclosed. Systems include an in-line or linear bladder apparatus configured to expand to collect a charge of fluid, and contract to assist with fluid delivery and dispensing. During a dispense-off period process fluid can collect in this bladder after the process fluid is pushed through a fine filter (micro filter). A given filtration rate can be less than a dispense rate and thus the system herein compensates for filter-lag that often accompanies fluid filtering for microfabrication, while providing a generally linear configuration that reduces chances for defect creation.