Blank Photomask Conductive Layer for Electrostatic Discharge Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Photomasks suffer from damage due to electrostatic discharge current between isolated patterns, leading to reduced reliability and lifespan, especially when repeatedly used in photolithography processes.
Innovation Solution
A conductive layer with controlled electrical conductivity (500 S/cm to 2000 S/cm) is integrated into the blank mask, comprising layers with varying oxygen content to manage discharge current and voltage, reducing current density and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the photomask is repeatedly used in photolithography processes, then productivity increases, but electrostatic charges accumulate causing pattern damage
Solution Approach 1:
The patent converts the harmful effect of electrostatic charge accumulation into a beneficial outcome by designing a conductive layer that allows controlled discharge. The conductive layer with specific electrical conductivity (500-2000 S/cm) enables static electricity to be safely dissipated through the substrate, transforming the harmful charge accumulation into a controlled electrical discharge process that protects the pattern structure
Solution Approach 2:
The conductive layer acts as an intermediary between the insulating pattern materials and the ground potential. This intermediate conductive path allows electrostatic charges to be gradually discharged through the substrate without creating high-voltage breakdown between adjacent patterns, serving as a mediator that prevents direct harmful discharge while maintaining pattern functionality
2Reliability
If the electrical conductivity of the conductive layer is increased, then discharge voltage increases, but current density increases causing more heat generation
Solution Approach 1:
The patent optimizes the electrical conductivity parameter of the conductive layer to a specific range (500-2000 S/cm). This parameter change balances two opposing requirements: sufficient conductivity to provide adequate discharge voltage for pattern protection, while limiting current density to reduce Joule heating. The conductive layer's resistance is tuned to allow slow, controlled discharge rather than rapid high-current discharge
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 solution enhances photomask reliability by minimizing discharge current and heat-induced damage, allowing for uniform and fine line widths in circuit patterns, thereby extending the photomask's lifespan and improving manufacturing precision.
Implementation Method 1
electrostatic charges charged to the photomask accumulate, and when a charge difference between the patterns exceeds a breakdown voltage, static electricity is generated between the patterns
Implementation Method 2
an intensity of the discharge current due to static electricity is reduced. Accordingly, a size of a heating temperature due to the discharge current is reduced
Data Source
AI summary
A blank mask according to an embodiment includes a substrate; and a conductive layer disposed on the substrate, the conductive layer includes a first layer and a second layer having different electrical conductivities, and the electrical conductivity of the conductive layer is 500 S/cm to 2000 S/cm.