Semiconductor Interconnect Isolation via Damascene Process
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to maintain the integrity of dielectric spacing in interconnect structures as they shrink, as existing methods face issues with peeling or shifting during patterning, leading to increased contact resistances and fabrication complexities in advanced IC designs like FinFET devices.
Innovation Solution
A damascene-like process is employed to form an isolation structure by recessing an interlayer dielectric and filling it with a dielectric material, avoiding the formation of island-like patterns and mitigating lithography limitations, thus enhancing the length of interconnect structures and reducing contact resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional patterning methods are used to form dielectric spacing, then the critical dimensions can be reduced, but the dielectric spacing structure peels or shifts during patterning, leading to increased contact resistance
Solution Approach 1:
Instead of forming island-like dielectric spacing structures that are prone to peeling and shifting during conventional patterning, the patent inverts the approach by forming a continuous dielectric layer and then selectively removing portions to create spacing regions. This inversion eliminates the peeling and shifting problems while maintaining precise critical dimensions.
Solution Approach 2:
The patent applies preliminary action by first forming the complete dielectric layer with proper spacing regions defined before subsequent patterning steps. The dielectric spacing structure is established in advance with appropriate material properties and geometric configuration that prevent peeling and shifting during later processing.
2Reliability
If the length of interconnect structures is increased to reduce contact resistance, then the critical dimensions must be shrunk, but this increases fabrication complexity
Solution Approach 1:
The patent addresses the contact resistance issue by extending interconnect structures in the vertical dimension through multi-layer interconnect architecture rather than solely relying on horizontal dimension scaling. This allows longer effective interconnect paths without proportionally increasing planar critical dimensions, thereby reducing contact resistance while managing fabrication complexity.
3Ease of manufacture
If conventional island-like patterns are used for dielectric spacing, then lithography can be simplified, but the structures are prone to peeling and shifting during patterning
Solution Approach 1:
The patent inverts the conventional island-like pattern approach by using a continuous dielectric layer with selectively removed portions. This inversion maintains lithography simplicity while eliminating the peeling and shifting problems inherent in discrete island patterns, as the continuous layer provides structural support and uniform material properties throughout the spacing regions.
Data Source
AI summary
A semiconductor device includes a first source/drain structure coupled to an end of a first conduction channel that extends along a first direction. The semiconductor device includes a second source/drain structure coupled to an end of a second conduction channel that extends along the first direction. The semiconductor device includes a first interconnect structure extending through an interlayer dielectric and electrically coupled to the first source/drain structure. The semiconductor device includes a second interconnect structure extending through the interlayer dielectric and electrically coupled to the second source/drain structure. The semiconductor device includes a first isolation structure disposed between the first and second source/drain structures and extending into the interlayer dielectric.