Hybrid Wafer Bonding Barrier Structure for Copper Diffusion
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Solution Overview
Problem
In hybrid wafer bonding processes, contact vias with different sizes can lead to interactions between the contact via of one semiconductor structure and the dielectric layer, causing copper diffusion and degradation of bonded wafers, and conventional solutions result in defects due to differing etching rates and the formation of gaps between metal blocking layers and dielectric layers.
Innovation Solution
A hybrid wafer bonding method involving the formation of a barrier structure on non-overlapped surfaces of contact via surfaces using a multi-component oxide alloying process, which blocks copper diffusion by reacting metal impurities with oxides at the bonding interface, eliminating the need for additional deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal blocking layer is deposited on the bonding surface to prevent copper diffusion, then copper diffusion into the dielectric layer is blocked, but gaps form between the metal blocking layer and dielectric layer due to different etching rates, causing defects in the contact via
Solution Approach 1:
The contact via structure performs dual functions: it serves as both the conductive pathway and its own blocking layer. The metal impurities doped in the contact via create an alloying effect that forms a barrier structure during the bonding process, eliminating the need for separate metal blocking layers and avoiding the gaps caused by differential etching
Solution Approach 2:
The invention merges the conductive function and the blocking function into a single integrated structure. The contact via with metal impurities combines electrical conductivity with diffusion barrier properties, eliminating the interface between separate layers that causes gaps and defects
2Adaptability or versatility
If contact vias of different sizes are used in hybrid wafer bonding, then different functional requirements are met, but interactions occur between the contact via of one structure and the dielectric layer of the other, causing copper diffusion
Solution Approach 1:
The invention applies local quality by doping metal impurities specifically in the contact via regions that require blocking functionality. The metal impurities are concentrated at the bonding interface where diffusion prevention is needed, while maintaining the original contact via size variations for different functional requirements
Solution Approach 2:
The metal impurities act as an intermediary substance within the contact via, mediating between the conductive copper and the dielectric layer. During bonding, these impurities form an alloying barrier structure that prevents copper diffusion while allowing the contact via to maintain its conductive function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively prevents copper diffusion into dielectric layers, enhancing the quality of bonded wafers by forming a self-barrier structure that maintains structural integrity and electrical conductivity.
Implementation Method 1
forming a barrier structure on a non-overlapped surface of one or more of the first and second contact via surfaces by an alloying process between the first semiconductor structure and the second semiconductor structure
Implementation Method 2
the barrier structure is formed by a multi-component oxide corresponding to the first and second metal impurities
Data Source
AI summary
A hybrid wafer bonding method includes providing a first semiconductor structure and providing a second semiconductor structure. The first semiconductor structure includes a first via structure in a first dielectric layer, the first via structure including a first contact via surface. The second semiconductor structure includes a second via structure in a second dielectric layer, the second via structure including a second contact via surface. The first contact via surface is bonded with the second contact via surface. A barrier structure is formed surrounding the second contact via surface along a lateral direction and extending into each of the first contact via surface and the second dielectric layer in a vertical direction. The first via structure includes first metal impurities doped in a bulk region of the first via structure, and the second via structure includes second metal impurities doped in a bulk region of the second via structure.