Resist Dispensing Nozzle Solvent Buffer Against Crystallization
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Solution Overview
Problem
The existing lithography processes face challenges in maintaining the purity and preventing crystallization of resist materials during dispensing, leading to defects and non-uniformity in the resist layer on wafers, which can result in critical dimension (CD) non-uniformity and device yield issues.
Innovation Solution
A resist material dispensing system that uses a nozzle with a specific solvent management system, where a second solvent with a higher vapor pressure is used to prevent the first solvent from evaporating, keeping the resist material residues in a liquid state and preventing crystallization, and includes a cleaning mechanism to remove residues, thereby reducing defects in the deposited resist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resist material is dispensed through a nozzle during lithography processing, then the resist layer can be applied to the wafer, but the solvent in the resist material may evaporate during idle periods, causing the resist material to crystallize and create defects
Solution Approach 1:
A second solvent is introduced as an intermediary substance to prevent the first solvent from evaporating. The second solvent has higher vapor pressure than the first solvent, so it preferentially evaporates instead of the first solvent, thereby preventing resist material crystallization in the nozzle during idle periods between wafers.
Solution Approach 2:
The system changes the vapor pressure parameter by introducing a second solvent with higher vapor pressure than the first solvent. This parameter change ensures that the second solvent evaporates preferentially, maintaining the liquid state of the resist material residues and preventing crystallization defects.
2Productivity
If the resist material is kept in the nozzle for continuous dispensing, then the lithography process can proceed without interruption, but the solvent evaporates and causes crystallization of resist material residues
Solution Approach 1:
The second solvent acts as a protective intermediary that remains in the nozzle during idle periods, preventing the first solvent from evaporating and the resist material from crystallizing. This allows the system to maintain continuous dispensing capability without compromising resist layer uniformity.
Solution Approach 2:
The second solvent is introduced into the nozzle in advance before idle periods occur. This preliminary action ensures that when idle periods happen between wafers, the resist material is already protected from evaporation and crystallization, maintaining manufacturing precision throughout the continuous process.
3Reliability
If the nozzle is cleaned frequently to remove resist material residues, then crystallization defects can be prevented, but the lithography process efficiency decreases due to interruptions
Solution Approach 1:
The second solvent serves as a protective intermediary that prevents resist material crystallization during idle periods, eliminating the need for frequent nozzle cleaning interruptions. This maintains both high reliability (defect reduction) and high productivity (process efficiency).
Solution Approach 2:
The second solvent automatically performs the protective function of preventing crystallization during idle periods without requiring external intervention or cleaning operations. The system self-maintains the nozzle in a defect-free state, improving both reliability and productivity.
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 prevents the crystallization of resist material residues, reducing defects and ensuring a uniform resist layer, thereby improving the device yield and maintaining high resolution in lithographic processes.
Implementation Method 1
The gap includes vapor of the first solvent. The vapor of the first solvent in the gap prevents the resist material residues from drying.
Implementation Method 2
a second solvent with a higher vapor pressure is used to prevent the first solvent from evaporating
Implementation Method 3
a second solvent with a higher vapor pressure is used to prevent the first solvent from evaporating
Implementation Method 4
includes a cleaning mechanism to remove residues
Data Source
AI summary
In a method, a resist material is dispensed through a tube of a nozzle of a resist pump system on a wafer. The tube extends from a top to a bottom of the nozzle and has upper, lower, and middle segments. When not dispensing, the resist material is retracted from the lower and the middle segments, and maintained in the upper segment of the tube. When retracting, a first solvent is flown through a tip of the nozzle at the bottom of the nozzle to fill the lower segment of the tube with the first solvent and to produce a gap in the middle segment of the tube between the resist material and the first solvent. The middle segment includes resist material residues on an inner surface wall of the tube and vapor of the first solvent. The vapor of the first solvent prevents the resist material residues from drying.