Semiconductor Interconnect Structure With Spacer-Protected Metal Via
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity of fabrication processes due to decreased feature sizes, which complicates the formation of semiconductor structures.
Innovation Solution
A method involving the use of a spacer layer to protect metal lines during etching processes, preventing time-dependent dielectric breakdown and providing isolation, while also forming spacers in-situ to avoid damage from atmospheric exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase functional density, then productivity is improved, but manufacturing precision deteriorates due to increased fabrication complexity
Solution Approach 1:
A spacer layer is formed over the metal line before subsequent etching processes. This preliminary protective action prevents direct exposure of the metal line to etching chemicals, thereby maintaining manufacturing precision even as feature sizes decrease and fabrication complexity increases.
Solution Approach 2:
The spacer layer acts as an intermediary protective barrier between the metal line and the etching environment. This intermediate structure shields the metal line from damage while allowing the etching process to proceed, resolving the contradiction between increased productivity through scaling and maintained manufacturing precision.
2Device complexity
If metal lines are exposed during etching processes, then manufacturing complexity is reduced, but reliability deteriorates due to time-dependent dielectric breakdown and atmospheric damage
Solution Approach 1:
The spacer layer is formed over the metal line before etching begins, providing preliminary protection against atmospheric exposure and etching damage. This preliminary action maintains reliability without significantly increasing processing complexity, as the spacer formation is integrated into the existing fabrication sequence.
Solution Approach 2:
The spacer layer serves as an intermediary protective barrier that prevents direct contact between the metal line and harmful environmental factors during etching. This intermediate structure maintains electrical integrity while allowing the etching process to proceed with standard complexity.
3Reliability
If spacer layer is formed to protect metal lines, then reliability is improved, but device complexity increases
Solution Approach 1:
The spacer layer performs multiple functions simultaneously: it protects the metal line from atmospheric exposure, provides etch isolation, and maintains structural integrity during subsequent processing. This multi-functionality improves reliability without proportionally increasing device complexity, as a single structure achieves multiple protective goals.
Solution Approach 2:
The spacer layer is implemented as a thin film structure that provides comprehensive protection with minimal added complexity. The thin film nature allows it to be integrated into existing device architectures without significantly increasing structural complexity, while still delivering substantial reliability improvements.
Data Source
AI summary
A semiconductor structure includes a substrate, a gate structure, source/drain epitaxial structures, a contact structure, a first via structure, a metal line, a hard mask layer, a spacer layer, and a second via structure. The gate structure is formed over the substrate. The source/drain epitaxial structures are formed on opposite sides of the gate structure. The contact structure is formed over one of the source/drain epitaxial structures. The first via structure is formed over the contact structure. The metal line is electrically connected to the first via structure. The hard mask layer is formed over the metal line. The spacer layer is formed over a top surface of the hard mask layer and over a sidewall of metal line. The second via structure is formed over the metal line through the spacer layer.