Dangling Vias Enhance Semiconductor Reliability
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Solution Overview
Problem
In semiconductor processing, vias between conductive layers face reliability issues due to high density and tight pitch, leading to potential failures, especially in areas where adding redundant vias is not feasible without increasing the integrated circuit area.
Innovation Solution
A dangling via is introduced, electrically isolated from operational vias, to enhance reliability without requiring additional space, by forming it between conductive lines where a redundant via is not possible, thereby addressing the susceptibility to outgassing and structural instability of lonely vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant vias are added to improve reliability, then via failure risk is reduced, but integrated circuit area increases
Solution Approach 1:
The invention segments the via structure into two distinct components: the primary via that provides the main electrical connection, and the dangling via that serves solely as a reliability enhancement. This segmentation allows the reliability function to be separated from the signal transmission function, enabling the dangling via to be positioned optimally for reliability without constraining the primary via's electrical performance.
Solution Approach 2:
The dangling via acts as an intermediary element between the primary via and the via failure risk. It provides a backup conduction path that mediates the reliability concern without directly interfering with the primary via's electrical connection. The dangling via's electrical isolation from the primary via allows it to function purely as a reliability backup.
2Quantity of substance
If via density is increased to maintain area, then more connections are possible, but via reliability decreases due to outgassing and structural instability
Solution Approach 1:
The invention applies local quality by creating different via types in different locations: primary vias for electrical connection and dangling vias for reliability. The dangling via is specifically positioned and configured with electrical isolation to address local reliability concerns without affecting the overall via density. This localized approach allows high via density to be maintained while specific reliability-prone areas are enhanced.
Solution Approach 2:
The invention changes the electrical parameter state of the dangling via by making it electrically isolated from the primary via. This parameter change (from electrically connected to electrically isolated) allows the dangling via to serve purely as a structural and reliability element, eliminating outgassing issues while maintaining the benefits of high via density for electrical connections.
3Area of stationary object
If tight pitch is used to reduce area, then integrated circuit area is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The invention resolves the tight pitch manufacturing challenge by utilizing the vertical dimension and electrical isolation properties. Instead of trying to place redundant vias horizontally (which would require more area and tighter pitch), the dangling via is positioned to be electrically isolated, allowing it to be placed in locations that optimize reliability without increasing horizontal density requirements. This dimensional approach to reliability enhancement avoids exacerbating the manufacturing precision challenges.
Data Source
AI summary
Another semiconductor device includes a first layer including a plurality of electrically conductive wires, a second layer, a plurality of non-functional via pads are included in the second layer or between the first layer and the second layer. A dangling via is included within a specified area of the first layer. The dangling vias connect one or more of the wires in the first layer to a respective one of the via pads.