Recessed Via Structure for IC Wire Isolation Reliability
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Solution Overview
Problem
Existing via structures in integrated circuit devices often face challenges in maintaining stable electrical connections while minimizing unintended electrical connections between via contacts and adjacent conductive elements, due to insufficient control over the distance between conductive wires and vias.
Innovation Solution
The method involves forming a recessed upper surface of conductive wires within an insulating layer, using a mask layer that is selectively removed to create a precise distance between the conductive wires and the via, with an etch stop layer and additional insulating layers to ensure accurate via placement and reduce the likelihood of unintended connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional via structures are used without recessed conductive wires, then the manufacturing process is simpler, but the distance between conductive wires and vias is insufficient leading to unintended electrical connections
Solution Approach 1:
The conductive wire upper surface is recessed below the insulating layer surface before via formation. This preliminary action creates a built-in safety margin that ensures sufficient distance between the via contact and conductive wire even with manufacturing variations, preventing unintended electrical connections while maintaining reliable electrical connection.
Solution Approach 2:
The via structure is segmented into multiple functional zones: the via contact extending into the recess, the etch stop layer positioned between the via contact and conductive wire, and the insulating layer. This segmentation allows each component to perform its specific function independently, with the etch stop layer acting as a barrier to prevent direct contact between via and conductive wire.
2Reliability
If the distance between conductive wires and vias is increased to prevent unintended connections, then reliability improves, but manufacturing precision requirements increase
Solution Approach 1:
The conductive wire upper surface is recessed below the insulating layer surface before via formation. This preliminary action creates a built-in safety margin that ensures sufficient distance between the via contact and conductive wire even with manufacturing variations, preventing unintended electrical connections while maintaining reliable electrical connection.
Solution Approach 2:
The etch stop layer is introduced as an intermediary component positioned between the via contact and the conductive wire. This intermediate layer provides an additional safety barrier that prevents unintended electrical connections even if via placement varies, reducing the stringency of via placement precision requirements.
3Manufacturing precision
If mask layer is selectively removed to create recess, then precise distance control is achieved, but additional manufacturing steps are required
Solution Approach 1:
The mask layer serves multiple functions: it defines the conductive wire pattern during formation, and subsequently serves as an etch mask to create the recess when selectively removed. This multi-functionality consolidates pattern definition and recess formation into a integrated process flow, achieving precise distance control without adding excessive process complexity.
Data Source
AI summary
Integrated circuit devices including a via and methods of forming the same are provided. The methods may include forming a conductive wire structure on a substrate. The conductive wire structure may include a first insulating layer and a conductive wire stack in the first insulating layer, and the conductive wire stack may include a conductive wire and a mask layer stacked on the substrate. The method may also include forming a recess in the first insulating layer by removing the mask layer, the recess exposing the conductive wire, forming an etch stop layer and then a second insulating layer on the first insulating layer and in the recess of the first insulating layer, and forming a conductive via extending through the second insulating layer and the etch stop layer and contacting the conductive wire.