Semiconductor Device Multi-Level Wiring Via Structure
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Solution Overview
Problem
As semiconductor elements continue to downscale, there is a challenge in stably forming wirings and via holes for connecting them across multiple metal levels, which affects the routability and reliability of semiconductor devices.
Innovation Solution
The semiconductor device incorporates a via structure that directly connects wirings across different metal levels, using interlayer insulating layers and filling layers to enhance connectivity and reduce unnecessary space, thereby improving routability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional wiring connection methods are used across multiple metal levels, then the wiring structure is simpler, but the routability is poor and additional space is required at specific metal levels
Solution Approach 1:
The patent introduces via holes that extend in the vertical dimension to directly connect wirings across multiple metal levels (first metal level to second metal level), eliminating the need for intermediate connections at the second metal level. This dimensional approach to connectivity dramatically improves routability by allowing direct through-substrate connections.
Solution Approach 2:
The via holes are formed within and penetrate through the interlayer insulating layers, nesting the conductive pathways within the insulating structure. The via holes are embedded in the interlayer insulating layer, creating a nested configuration that achieves long-distance connectivity without adding external complexity.
2Adaptability or versatility
If via holes are used to connect wirings across multiple metal levels, then the routability is improved, but the manufacturing difficulty increases
Solution Approach 1:
The interlayer insulating layer is formed preliminarily before via hole formation, providing a pre-prepared medium in which via holes can be easily formed. This preliminary formation of the insulating layer with appropriate properties facilitates subsequent via hole creation and reduces manufacturing difficulty.
Solution Approach 2:
The interlayer insulating layer serves as an intermediary material that enables via hole formation and wiring connection. This intermediary layer with controlled dielectric properties and etch selectivity makes the via hole formation process more manageable and reduces overall manufacturing difficulty.
3Reliability
If direct via connections are implemented across metal levels, then the IR drop is reduced and reliability is improved, but the process complexity increases
Solution Approach 1:
The interlayer insulating layer performs multiple functions: it provides electrical insulation between metal levels, serves as a medium for via hole formation, and enables direct wiring connections. This multi-functionality reduces the need for additional specialized layers or processes, thereby limiting the increase in fabrication process complexity while achieving improved reliability.
4Reliability
If additional space is allocated at specific metal levels for connectivity, then the wiring connections are more stable, but the integration density decreases
Solution Approach 1:
By transitioning connectivity from a two-dimensional planar approach to a three-dimensional vertical approach via via holes, the patent eliminates the need for additional lateral space at intermediate metal levels. This dimensional shift maintains wiring connection stability while preserving integration density by utilizing the vertical dimension for connectivity.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a first wiring and a second wiring disposed at a first metal level, a third wiring and a fourth wiring disposed at a second metal level different from the first metal level, a first via which directly connects the first wiring and the third wiring, a fifth wiring disposed at a third metal level between the first metal level and the second metal level and connected to the second wiring, and a second via which directly connects the fourth wiring and the fifth wiring.