Photomask ESD Line with Comb-Shaped Edge Structure
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Solution Overview
Problem
Existing photomasks suffer from electrostatic discharge (ESD) damage during the photolithography process, particularly at the edges and corners of the circuit pattern, due to accumulated electric charges from frequent contact with mask holders, leading to pattern distortion and damage.
Innovation Solution
A photomask design featuring an electrostatic discharge (ESD) structure with a comb-shaped ESD line extending beyond the edge of the ESD structure, including segments and pins that protrude towards the substrate edge, effectively discharging electric charges away from the circuit pattern, thereby reducing ESD damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple ESD ring structure is used, then the device complexity is reduced, but the ESD protection effectiveness deteriorates
Solution Approach 1:
The ESD line is segmented into multiple comb-shaped structures with pins and segments arranged in series, creating multiple discharge points along the ESD line to enhance protection effectiveness
Solution Approach 2:
The ESD line extends beyond the edge of the substrate in addition to surrounding the circuit pattern, adding a dimensional element that provides additional discharge paths for edge-generated static electricity
2Reliability
If the ESD line extends beyond the substrate edge, then the ESD protection coverage is improved, but the manufacturing precision requirement increases
Solution Approach 1:
The ESD line is designed to extend beyond the substrate edge in advance, creating a buffer zone that allows static electricity to be discharged before reaching the circuit pattern, providing a safety margin for manufacturing variations
3Reliability
If comb-shaped structures with pins are added to the ESD line, then the charge discharge efficiency is improved, but the device complexity increases
Solution Approach 1:
Comb-shaped structures with pins are added at specific locations along the ESD line, particularly at the edge portion, to create localized high-efficiency discharge zones without making the entire structure complex
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 comb-shaped ESD line design efficiently discharges electric charges before they reach the circuit pattern, maintaining pattern accuracy and preventing damage from ESD effects, ensuring reliable semiconductor manufacturing.
Implementation Method 1
the ESD line includes an edge portion extending beyond an end of an edge of the ESD structure, and the edge portion of the ESD line includes at least one comb-shaped structure... efficiently discharges electric charges before they reach the circuit pattern
Data Source
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AI summary
A photomask is provided, the photomask includes a substrate (102), a circuit pattern (104) on the substrate (102), an electrostatic discharge (ESD) structure (106) on the substrate (102) and an ESD line (108a) on the substrate (102). The ESD structure (106) surrounds the circuit pattern (104). The ESD line (108a) extends between an edge of the substrate (102) and the ESD structure (106), in which the ESD line (108a) includes an edge portion (EP1a) extending beyond an end of an edge of the ESD structure (106), and the edge portion (EP1a) of the ESD line (108a) includes at least one comb-shaped structure (114).