Drain Line pH Sensor for Lithography Develop Process Control
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Solution Overview
Problem
Current substrate lithography processes face challenges in maintaining critical dimension targeting, line roughness, and uniformity due to the limitations of traditional photolithography methods, particularly in shrinking geometries, where the develop process lacks effective monitoring and control to prevent pH shock and excursions.
Innovation Solution
A liquid dispense unit equipped with a pH sensor and/or a line particle counter (LPC) is coupled to the drain line to monitor and optimize the develop process by detecting the endpoint, avoiding pH shock, and detecting excursions, thereby controlling operational parameters such as developer flow rate and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional photolithography develop process is used, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to pH shock and process excursions affecting critical dimension targeting and line roughness
Solution Approach 1:
The patent implements real-time pH monitoring of the develop solution through a pH sensor that continuously measures pH levels during the develop process. The system uses this feedback to detect endpoint conditions and identify process excursions, enabling dynamic adjustment of process parameters to maintain critical dimension precision without requiring complex external monitoring equipment
Solution Approach 2:
The develop process system monitors its own state through integrated pH sensing capabilities within the liquid dispense unit. The system self-diagnoses process excursions and endpoint conditions by analyzing pH variations in the develop solution, eliminating the need for separate complex monitoring systems while maintaining manufacturing precision
2Manufacturing precision
If traditional photolithography develop process is used, then device complexity is minimized, but manufacturing precision deteriorates due to lack of real-time monitoring causing line roughness and uniformity issues
Solution Approach 1:
The patent combines the pH sensing functionality directly with the liquid dispense unit by integrating the pH sensor into the drain line or solution delivery system. This merging of monitoring and dispensing functions into a single integrated unit enables real-time detection of process conditions affecting line roughness without adding separate complex monitoring equipment
Solution Approach 2:
The liquid dispense unit is designed with multi-functionality, serving both as the solution delivery mechanism and as the monitoring platform through integrated pH sensing. This universal design allows the same hardware component to perform both dispensing and quality monitoring functions, maintaining simplicity while improving line roughness control
3Productivity
If rapid pH transition from develop to rinse solution is used, then productivity is improved by reducing process time, but manufacturing precision deteriorates due to pH shock causing defectivity
Solution Approach 1:
The system performs preliminary detection of the develop process endpoint through real-time pH monitoring before the rinse process begins. By identifying the precise endpoint condition in advance, the system can initiate the rinse transition at the optimal moment, allowing for controlled pH transition that prevents defectivity while minimizing the time extension to the overall process
Solution Approach 2:
The real-time pH monitoring provides continuous feedback during the transition from develop to rinse solution. This feedback enables dynamic control of the transition rate, allowing the system to slow down the pH change when approaching critical thresholds to prevent pH shock-induced defects, while otherwise maintaining rapid transition to preserve productivity
4Manufacturing precision
If real-time pH monitoring is implemented, then manufacturing precision is improved by detecting process excursions, but device complexity increases due to additional sensors and control systems
Solution Approach 1:
The pH monitoring system is integrated into the existing liquid dispense unit infrastructure, allowing the system to monitor its own process conditions using the same hardware components already present for solution delivery. This self-service approach enables excursion detection without requiring entirely separate monitoring equipment, thereby limiting the increase in device complexity
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 solution enhances the precision and consistency of the develop process by optimizing the transition between develop and rinse solutions, reducing defectivity and improving productivity by preventing pH shock and detecting process deviations.
Implementation Method 1
a pH sensor and/or a line particle counter (LPC) is coupled to a drain line of the liquid dispense unit to monitor various parameters of the liquid waste
Implementation Method 2
the line particle counter (LPC) coupled to the drain line is used to detect an amount of conglomeration within the liquid waste ejected from the substrate
Data Source
AI summary
Various embodiments of systems and methods for drain line monitoring are disclosed herein. More specifically, a liquid dispense unit for a coating/developing processing system is provided herein for applying one or more liquid solutions to a substrate disposed within the liquid dispense unit. In the disclosed embodiments, a pH sensor and/or a line particle counter (LPC) is coupled to a drain line of the liquid dispense unit to monitor various parameters of the liquid waste, which is ejected from the substrate and disposed of through the drain line. In some embodiments, measurements obtained from the pH sensor may be used to optimize a develop process by detecting an endpoint of the develop process, avoiding pH shock and/or detecting excursions in the develop process. In some embodiments, measurements obtained from the LPC may additionally or alternatively be used to optimize the develop process.