Hybrid Bonding Structure Layout to Prevent Wafer Recess Defects
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Solution Overview
Problem
Large metal pads in semiconductor devices are prone to recesses and defects during manufacturing, leading to device failure.
Innovation Solution
A bonding structure is designed with non-overlapping arrangements of interconnection structures and conductive bonding pads, where the pad is formed at the backside of the second wafer and electrically connected to the interconnection structure in a non-overlapping manner, avoiding recess formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large metal pad is used for bonding, then the bonding area is increased, but recesses and defects occur during manufacturing
Solution Approach 1:
The bonding pad structure is segmented into multiple layers: a first conductive bonding pad layer and a second conductive bonding pad layer. This segmentation allows each layer to be optimized independently, preventing recess formation while maintaining adequate bonding area. The first pad layer provides the primary bonding interface, while the second pad layer compensates for any recesses in the first layer.
Solution Approach 2:
The solution transitions from a single-plane bonding pad to a multi-layer three-dimensional structure. By adding the second conductive bonding pad layer above the first layer, the bonding function is extended to another dimension, ensuring adequate contact area even when the first layer has recesses.
2Reliability
If a large metal pad is used for bonding, then the electrical connection is improved, but device failure occurs due to recesses
Solution Approach 1:
The second conductive bonding pad layer serves as a cushioning layer that compensates for recesses in the first conductive bonding pad layer before they can cause device failure. This prior cushioning ensures reliable electrical connection even when the first layer has manufacturing-induced recesses.
3Area of stationary object
If the interconnection structure and bonding pad are arranged in overlapping manner, then the space utilization is improved, but recesses are formed
Solution Approach 1:
Instead of arranging the interconnection structure and bonding pad in a non-overlapping manner in the same plane (which would waste space), the patent uses vertical stacking in the third dimension. The interconnection structure is positioned below the first conductive bonding pad layer, allowing horizontal overlap while preventing recess formation through the multi-layer pad structure.
Data Source
AI summary
A bonding structure and a manufacturing method therefor. A first hybrid bonding structure is formed on a first wafer; an interconnection structure and a second hybrid bonding structure are formed on the front surface of a second wafer. The first wafer and the second wafer are bonded by means of the first hybrid bonding structure and the second hybrid bonding structure, a gasket electrically connected to the interconnection structure is formed on the back surface of the second wafer, and the interconnection structure below the gasket and a second conductive bonding pad in the second hybrid bonding structure are provided in a staggered manner in the horizontal direction. According to the solution, the interconnection structure and the second conductive bonding pad are arranged in a staggered manner, so that recesses generated by structural stacking are avoided, and device failure caused by the recesses is further avoided.