Buried Wiring and Through-Substrate Isolation in Fin Semiconductor Layouts
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Solution Overview
Problem
Undesired short-circuits occur between metal wiring and active regions in semiconductor devices due to reduced size and pitch of active elements and metal wiring, leading to connectivity issues.
Innovation Solution
A semiconductor device design featuring a substrate with active fins, buried conductive wiring, and a conductive through structure that includes a dielectric liner to prevent short-circuits by ensuring a sufficient distance from active regions and using a filling insulation portion to cover the buried conductive wiring, along with a conductive through structure that extends through the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of active elements and metal wiring is reduced to achieve higher integration, then device density and functionality are improved, but the risk of short-circuits between metal wiring and active regions increases
Solution Approach 1:
A dielectric liner is introduced as an intermediary layer between the conductive through structure and the active region. This liner acts as a protective mediator that prevents direct contact and potential short-circuits while allowing the conductive structure to maintain its electrical connection function. The dielectric material provides electrical isolation without compromising the overall device integration density.
Solution Approach 2:
The dielectric liner is formed beforehand to cover potential misalignment issues before final device operation. By providing a protective layer in advance, the design cushions against the increased short-circuit risk that arises from reduced dimensional tolerances in highly integrated devices.
2Device complexity
If the pitch of metal wiring is reduced to increase integration, then device complexity is reduced, but manufacturing precision requirements increase due to shorter distances between components
Solution Approach 1:
The dielectric liner serves as a buffer that tolerates manufacturing variations. Even if alignment is not perfectly precise, the liner ensures that the conductive through structure does not directly contact the active region, thereby reducing the stringency of manufacturing precision requirements.
Solution Approach 2:
The introduction of the dielectric liner changes the structural parameters of the through-hole filling, transforming it from a simple conductive fill to a composite structure with insulating and conductive layers. This parameter change provides a safety margin that accommodates pitch reduction without proportionally increasing manufacturing difficulty.
3Reliability
If larger conductive through structures are used to ensure connectivity, then electrical connection reliability is improved, but the distance to active regions decreases increasing short-circuit risk
Solution Approach 1:
The dielectric liner is positioned between the conductive through structure and the active region, serving as a physical and electrical mediator. This allows the conductive structure to maintain its larger cross-section for reliable electrical connection while the liner prevents the harmful effect of direct contact with the active region.
Solution Approach 2:
The through-hole structure is segmented into distinct functional zones: a dielectric liner layer for isolation and a conductive core for electrical connection. This segmentation allows each part to optimize its function - the liner provides safety margin while the conductive portion ensures connectivity - without the conflicting requirements interfering with each other.
Data Source
AI summary
A semiconductor device includes a substrate having a first and second surface opposite to each other, and an active region on the first surface and defined by a first isolation region; a plurality of active fins on the active region, extending in a first direction, and defined by a second isolation region having a second depth smaller than a first depth of the first isolation region; a buried conductive wiring in a trench adjacent to the fins, and extending in a direction of the trench; a filling insulation portion in the trench, and having the wiring therein; an interlayer insulation layer on the first and second isolation regions and on the buried conductive wiring; a contact structure penetrating the interlayer insulation layer, and contacting the buried conductive wiring; and a conductive through structure extending through the substrate from the second surface to the trench, and contacting the buried conductive wiring.