Semiconductor Wiring Air Gap Protection Pattern
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Solution Overview
Problem
Semiconductor devices face challenges in reducing RC-delay and cross-talk due to mis-alignment issues during the formation of air gaps between wiring structures, leading to communication between via holes and air gaps, which affects the reliability and performance of the devices.
Innovation Solution
A semiconductor device design incorporating a protection pattern with metal nitride, a spacer on the sidewall, and an insulating interlayer structure with air gaps between wiring structures, along with a capping pattern to prevent electromigration, ensures that via holes are not in communication with the air gaps, thereby preventing RC-delay and cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air gap is formed between wiring structures by etching process, then RC-delay and cross-talk are reduced, but the upper edge portion of the wiring structure is removed and via holes may be in communication with the air gap due to mis-alignment
Solution Approach 1:
A protection pattern is introduced as an intermediary structure between the wiring structure and the via hole formation process. This protection pattern serves as a sacrificial mask that defines the via hole position and prevents direct etching of the wiring structure upper edge, thereby eliminating the mis-alignment issue while maintaining the air gap benefits
Solution Approach 2:
The protection pattern is formed in advance before via hole formation, establishing a precise reference structure that guides subsequent via hole etching. This preliminary action ensures that via holes are correctly positioned relative to the wiring structures, preventing communication with air gaps while maintaining manufacturing feasibility
2Manufacturing precision
If a protection pattern is formed on wiring structures, then via hole mis-alignment is prevented, but the device structure becomes more complex
Solution Approach 1:
The protection pattern is merged with the air gap formation process by using the same etching steps to define both the protection pattern boundaries and the air gap regions. This integration reduces the number of separate process steps and simplifies the overall device structure despite the added functional layer
Data Source
AI summary
A semiconductor device may include a plurality of wiring structures spaced apart from each other, a protection pattern including a metal nitride on each of the wiring structures, a spacer on a sidewall of the protection pattern, and an insulating interlayer structure containing the wiring structures and having an air gap between the wiring structures.