Dummy Plug Dimensions for Stress Migration Suppression
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Solution Overview
Problem
Conventional semiconductor devices with damascene interconnections face reliability issues due to stress migration, which generates voids in via contacts and lower-layer interconnections, leading to degradation over time, especially when heat is generated during prolonged operation.
Innovation Solution
The implementation of a semiconductor device structure that includes a first interlayer insulating film, a lower-layer interconnection, a second interlayer insulating film with normal and dummy via holes, and a third interlayer insulating film with upper-layer interconnections, where the dummy plug is designed with specific dimensions to create a broken portion under the corner of the dummy via hole, reducing stress migration and void generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi via plug or dummy via plug structures are used, then the interconnection structure is formed, but voids are generated in the via plug or lower-layer interconnection portion due to stress migration, deteriorating reliability
Solution Approach 1:
The invention intentionally introduces a dummy plug with specific dimensional characteristics (short side larger than minimum interconnection width but smaller than minimum via hole diameter, long side larger than shortest interconnection length) that generates controlled stress migration in the dummy plug itself. This converts the harmful stress migration effect into a beneficial mechanism by sacrificing the dummy plug to protect the normal functional plugs from void formation, thereby improving overall interconnection reliability
Solution Approach 2:
The invention applies different quality characteristics to different regions: the dummy plug is designed with specific dimensional constraints to generate stress migration locally, while the normal plugs maintain standard dimensions for optimal electrical performance. The dummy plug's short side is specifically controlled to be larger than minimum interconnection width but smaller than minimum via hole diameter, creating localized stress distribution that protects surrounding functional structures
2Ease of manufacture
If the dummy plug dimensions are not properly controlled, then manufacturing is simplified, but the dummy plug fails to effectively suppress stress migration and void formation
Solution Approach 1:
The invention establishes specific parameter ranges for the dummy plug dimensions: the short side must be larger than the minimum interconnection width but smaller than the minimum via hole diameter, and the long side must be larger than the shortest interconnection length. These parameter constraints optimize the dummy plug's ability to suppress stress migration while remaining compatible with standard manufacturing processes
Data Source
AI summary
A semiconductor device is disclosed, which includes a first interlayer insulating film, a lower-layer interconnection in a first groove in the first film, a second interlayer insulating film over the first film, having a normal via hole opening to the lower-layer interconnection, a normal plug in the normal hole, a third interlayer insulating film over the second film, having a second groove opening to the normal plug, an upper-layer interconnection in the second groove, and a first dummy plug in a first dummy via hole in the second film, the first dummy via hole opening to one of the lower-layer and upper-layer interconnections, wherein a short side of the first dummy plug is larger than a minimum width of a minimum width interconnection and smaller than a minimum diameter of a minimum diameter via hole and a long side is larger than a shortest length of a shortest length interconnection.