Annular Contact Bonding Pad Crack Containment
Solution Overview
Problem
Conventional semiconductor devices experience cracks in the insulating film due to thrust forces during wafer testing, leading to potential water ingress and corrosion, especially in higher-integrated devices where the distance between bonding pads and interconnects is reduced, resulting in reliability issues.
Innovation Solution
Incorporating an annular contact within the insulating film between the bonding pads to encircle the central opening, which restricts crack growth and prevents water ingress by creating a barrier against stress concentration and crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between bonding pad and interconnect is reduced to achieve higher integration, then productivity and device density are improved, but the reliability deteriorates due to increased crack propagation risk
Solution Approach 1:
The patent divides the bonding pad structure into multiple segments: a first bonding pad, a second bonding pad, and an annular contact between them. This segmentation creates distinct functional zones where the annular contact acts as an independent barrier element that can stop crack propagation without affecting the overall bonding pad functionality, thus maintaining reliability while allowing reduced spacing between pads
Solution Approach 2:
The annular contact serves as an intermediary element positioned between the first and second bonding pads. This intermediate structure acts as a crack propagation barrier that protects the interconnect from cracks originating at either bonding pad, enabling closer pad spacing while maintaining protection of the interconnect layer
2Device complexity
If conventional bonding pad structure is used, then device complexity is low and manufacturing is simple, but cracks propagate to interconnect causing water ingress and corrosion
Solution Approach 1:
The annular contact is formed in advance during the manufacturing process, before final device assembly and testing. This preliminary structural preparation ensures that the crack propagation barrier is already in place to prevent water ingress pathways, addressing the harmful effect before it can occur during subsequent wafer testing or operation
Solution Approach 2:
The annular contact provides beforehand protection by creating a mechanical barrier that cushions against crack propagation. This preventive structure is built into the device architecture to absorb and deflect crack energy before it can reach the interconnect, preventing the harmful sequence of crack-water ingress-corrosion
Data Source
AI summary
A bonding pad structure in a semiconductor device includes a contact pad connected to an interconnect, a bonding pad overlying the contact pad with an intervention of an insulating film and exposed from an opening of a passivation film, and an annular contact disposed between the contact pad and the bonding pad for electric connection therebetween. The annular contact encircles the opening as viewed normal to the substrate surface.