Semiconductor Interconnect Structure Preventing Dielectric Breakdown
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Solution Overview
Problem
Multilayer interconnect structures in semiconductor devices are prone to leakage current issues due to the breakdown of dielectric layers between interconnect members, which is exacerbated by the reduction in distance between these members as integration levels increase, making it difficult to form reliable electrical connections.
Innovation Solution
A semiconductor structure and fabrication method involving a semiconductor substrate with a first dielectric layer having specific regions and openings, where interconnect members are formed with controlled dimensions and a second dielectric layer is used to create a through hole that exposes the top surface of the interconnect members, allowing for electrical connection while maintaining sufficient distance to prevent dielectric layer breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between interconnect members is reduced to increase integration level, then the density of interconnections is improved, but the dielectric layer breaks down and leakage current occurs
Solution Approach 1:
The patent introduces a vertical dimension by forming the second interconnect member partially within the first dielectric layer and the third opening extending through the second dielectric layer to expose the top surface of the first interconnect member. This three-dimensional arrangement allows interconnect members to be positioned at different vertical levels while maintaining sufficient horizontal spacing, thereby preventing dielectric breakdown while achieving high integration.
Solution Approach 2:
The patent segments the interconnect structure into multiple layers with different dielectric materials. The first dielectric layer contains the second interconnect member, while the second dielectric layer contains the third opening and interconnect structure. This segmentation allows each layer to be optimized independently, with the first dielectric layer providing isolation for closely spaced second interconnect members and the second dielectric layer providing a pathway for vertical connections.
2Productivity
If multiple interconnect layers are stacked to achieve high density, then the integration level is improved, but the complexity of fabrication process increases
Solution Approach 1:
The patent performs preliminary actions by forming the first dielectric layer and second interconnect members before forming the second dielectric layer and third opening. The top surfaces of the second interconnect members are prepared to be lower than the top surface of the first dielectric layer, which simplifies subsequent processing steps and ensures proper alignment and exposure of the first interconnect member top surface.
3Reliability
If the top surface of second interconnect member is made lower than the top surface of first dielectric layer, then the distance for electrical connection is sufficient, but the manufacturing precision requirement increases
Solution Approach 1:
The patent applies local quality by making the top surfaces of the second interconnect members selectively lower than the top surface of the first dielectric layer, while the first interconnect member remains at a different elevation. This localized depth differentiation is achieved through selective etching and deposition processes that modify specific regions of the structure without affecting other areas, thereby maintaining sufficient clearance while managing manufacturing complexity.
Data Source
AI summary
Semiconductor structures and fabrication methods are provided. An exemplary fabrication method includes providing a semiconductor substrate; forming a first dielectric layer having a first region and a second regions at each of two sides of the first region on the semiconductor substrate; forming a first opening in the first region of the first dielectric layer and a second opening in each of the second regions of the first dielectric layer; forming a first interconnect member in the first opening; forming a second interconnect member with a top surface lower than a top surface of the first dielectric layer in each of the second openings; forming a second dielectric layer having a third opening with a bottom exposing a top surface of the first interconnect member on surfaces of the first interconnect member, second interconnect members and the first dielectric layer; and forming an interconnect structure in the third opening.