Photolithography Mask Ionization to Prevent Electrostatic Discharge
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Solution Overview
Problem
The accumulation of electrostatic charge on masks during semiconductor fabrication leads to electrostatic discharge, damaging mask patterns and reducing yield rates, particularly in high-density and high-performance device fabrication where electrostatic charge is not effectively neutralized.
Innovation Solution
Incorporating ionizers in inspection and processing chambers to generate ions that neutralize electrostatic charge on masks, reducing the risk of electrostatic discharge by balancing charge imbalances and improving production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photolithography operations are performed without ionization treatment, then the fabrication process is simpler and faster, but electrostatic charge accumulates on masks causing discharge and pattern damage
Solution Approach 1:
The system performs ionization treatment of the atmosphere in the chamber before and during photolithography operations. This preliminary action prevents electrostatic charge accumulation on masks before it can cause discharge, thereby protecting mask pattern integrity while maintaining a relatively simple fabrication process flow
Solution Approach 2:
The patent introduces ions as an intermediary substance to neutralize electrostatic charge on masks. The ionization source generates positive and negative ions that act as mediators to balance charge imbalances on mask surfaces, preventing electrostatic discharge without requiring direct modification of the mask structure or photolithography process
2Reliability
If ionization treatment is applied continuously, then electrostatic charge is effectively neutralized, but energy consumption increases
Solution Approach 1:
The system applies ionization treatment periodically rather than continuously. The controller activates the ionization source during critical phases when masks are present and electrostatic charge accumulation is most likely, then deactivates it during non-critical periods, effectively neutralizing charge while minimizing energy consumption
Solution Approach 2:
The system monitors electrostatic charge conditions in the chamber and adjusts ionization treatment accordingly. When charge accumulation is detected or anticipated, ionization is activated; when conditions are stable, ionization is reduced or stopped, optimizing the balance between charge neutralization effectiveness and energy consumption
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
Effectively alleviates electrostatic discharge, enhancing yield rates and production efficiency by neutralizing electrostatic charge on masks, thereby maintaining mask integrity and reducing defects in semiconductor devices.
Implementation Method 1
Incorporating ionizers in inspection and processing chambers to generate ions that neutralize electrostatic charge on masks
Implementation Method 2
generate ions that neutralize electrostatic charge on masks, reducing the risk of electrostatic discharge by balancing charge imbalances
Data Source
AI summary
A method for fabricating a semiconductor structure, including disposing a mask at a first position in a first chamber, generating a first plurality of ions toward the mask by an ionizer, forming a photoresist layer on a substrate, receiving the substrate in the first chamber, and exposing the photoresist layer with actinic radiation through the mask in the first chamber.