Hybrid Bonding Air Gap Prevents Metal Diffusion
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Solution Overview
Problem
In 3D integrated circuit technology, misalignment during wafer bonding leads to metal atoms diffusing into the interlayer dielectric, causing contamination.
Innovation Solution
A hybrid bonding structure is created with a conductive structure comprising a conductive layer, a barrier, and an air gap surrounding the barrier, which prevents metal diffusion by forming an air gap fabricating method involving etching and deposition processes to separate the conductive and dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If misalignment occurs during wafer bonding, then bonding efficiency is maintained, but metal atoms diffuse into the interlayer dielectric causing contamination
Solution Approach 1:
An air gap is introduced as an intermediary layer between the conductive layer and the interlayer dielectric. This air gap acts as a physical barrier that prevents metal atom diffusion into the dielectric material while allowing the bonding process to proceed even with misalignment. The air gap is formed by selectively removing portions of the dielectric layer around the conductive structures.
Solution Approach 2:
The dielectric layer is segmented by selectively removing portions around the conductive layers, creating discrete air gap regions. This segmentation isolates each conductive structure with its own protective air gap, preventing metal diffusion into adjacent dielectric areas while maintaining the overall structural integrity of the bonded assembly.
2Object-affected harmful factors
If air gap is introduced to prevent metal diffusion, then contamination is reduced, but device complexity increases
Solution Approach 1:
The air gap structure is formed in advance during the fabrication process, before the final bonding operation. By pre-forming the protective air gaps around conductive layers, the structure is prepared to prevent metal diffusion without requiring additional corrective measures after bonding, thereby managing complexity proactively rather than reactively.
Data Source
AI summary
A hybrid bonding structure includes a first conductive structure and a second conductive structure. The first conductive structure includes a first conductive layer. A first barrier surrounds the first conductive layer. A first air gap surrounds and contacts the first barrier. A first dielectric layer surrounds and contacts the first air gap. The second conductive structure includes a second conductive layer. A second barrier contacts the second conductive layer. A second dielectric layer surrounds the second barrier. The second conductive layer bonds to the first conductive layer. The first dielectric layer bonds to the second dielectric layer.