Semiconductor Via Structure Selective Conductive Deposition
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Solution Overview
Problem
In semiconductor devices, achieving a high-quality connection between conductive lines and vias with low resistance and high current capacity is challenging due to the difficulty in forming conductive structures that effectively connect to via structures without compromising the integrity of the via structure.
Innovation Solution
A conductive structure is formed only over the planar portion of a via structure, avoiding the protrusion portion, with a buffer layer and dielectric layer surrounding the protrusion to minimize contact resistance and maximize current capacity, using a method that includes forming a via structure with a planar and protrusion portion and selectively forming the conductive structure on the planar area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conductive structure is formed over the entire via structure surface, then the contact area is maximized, but the manufacturing precision and connection quality deteriorate due to the protrusion portion causing non-planar contact
Solution Approach 1:
The via structure surface is segmented into a planar portion and a protrusion portion. The conductive structure is selectively formed only on the planar portion, separating the contact area into functional zones. This segmentation allows the planar portion to provide a high-quality contact surface while the protrusion portion can be optimized for other functions such as stress relief or electrical isolation.
Solution Approach 2:
Different regions of the via structure surface are given different qualities: the planar portion is optimized for conductive contact with flat, uniform surface properties, while the protrusion portion has different geometric properties suitable for its specific function. This local differentiation ensures that each region performs its intended function optimally without compromising the overall structure.
2Manufacturing precision
If the conductive structure is formed only on the planar portion, then the connection quality is improved, but the contact area is reduced
Solution Approach 1:
Instead of forming the conductive structure on the entire via surface, the process applies partial action by limiting the conductive material deposition to only the planar portion. This partial coverage is sufficient to achieve the required connection quality and current capacity while avoiding the detrimental effects of forming conductive material on the protrusion portion.
3Reliability
If a buffer layer is added to surround the protrusion portion, then the via structure integrity is protected, but the device complexity increases
Solution Approach 1:
A buffer layer is introduced as an intermediary element between the protrusion portion and the surrounding environment or adjacent structures. This buffer layer protects the protrusion portion from mechanical stress, chemical corrosion, or electrical interference, thereby enhancing via structure reliability without requiring fundamental redesign of the via geometry.
Solution Approach 2:
The buffer layer is formed in advance to surround and protect the protrusion portion before subsequent processing steps. This preemptive protection prevents potential damage to the via structure during fabrication or operation, ensuring long-term reliability by addressing potential failure modes before they occur.
Data Source
AI summary
A semiconductor device includes a via structure and a conductive structure. The via structure has a surface with a planar portion and a protrusion portion. The conductive structure is formed over at least part of the planar portion and not over at least part of the protrusion portion of the via structure. For example, the conductive structure is formed only onto the planar portion and not onto any of the protrusion portion for forming high quality connection between the conductive structure and the via structure.