Semiconductor Passivation Stress Relief via Dielectric Recess
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thermo-mechanical stresses in integrated circuits due to material mismatches between the passivation layer and metallization layers, particularly at the triple point where the capping layer, barrier layer, and passivation layer interface, lead to reliability issues during wire bonding and packaging processes.
Innovation Solution
A semiconductor device design that includes a dielectric layer between the passivation layer and the diffusion barrier layer, with a hollow recess area between the passivation layer and the barrier layer, decoupling the capping-barrier interface from the passivation top surface, and maintaining a dielectric layer on top of the passivation before defining via structures, while partially removing it after copper seed and barrier layer deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is deposited directly on the dielectric substrate with metallization layers, then the structure is simpler and manufacturing is easier, but thermo-mechanical stresses cause reliability issues at the triple point interface
Solution Approach 1:
The patent divides the interface region into separate functional zones by introducing a dielectric layer with a hollow recess. This segments the triple point interface into distinct regions: the passivation layer, the dielectric layer with recess, and the metallization layers, allowing each to be optimized independently for stress management while maintaining overall structural integrity.
Solution Approach 2:
The dielectric layer with hollow recess acts as an intermediary between the passivation layer and the metallization layers. This intermediate structure decouples the direct contact at the triple point, providing a buffer zone that manages thermo-mechanical stresses and prevents stress concentration while maintaining electrical and structural connectivity.
2Ease of manufacture
If the passivation layer is in direct contact with metallization layers at the triple point, then manufacturing steps are reduced, but stress concentration occurs leading to reliability issues
Solution Approach 1:
The hollow recess is formed in the dielectric layer before depositing the metallization layers. This preliminary action creates a pre-configured stress-management structure that prevents stress concentration before the metallization layers are added, addressing the reliability issue before manufacturing complexity becomes a concern.
Solution Approach 2:
The hollow recess is specifically located at the triple point interface region where stress concentration occurs. This local modification provides targeted stress relief precisely where needed, rather than requiring global structural changes, thus maintaining ease of manufacture while improving reliability at the critical interface.
3Reliability
If a dielectric layer with hollow recess is introduced to reduce stress, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The dielectric layer is segmented to include a hollow recess rather than being a continuous solid layer. This segmentation creates the stress-relief feature within the dielectric layer itself, integrating the stress management function into an existing layer rather than adding completely separate structural elements.
Solution Approach 2:
The hollow recess is nested within the dielectric layer, creating a cavity structure that provides stress relief while maintaining the overall layered architecture. This nesting approach incorporates the stress-management feature within the existing layer structure rather than adding external components.
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
This design significantly reduces stress on the silicon nitride passivation layer by eliminating the triple point, thereby enhancing the reliability of the semiconductor device under thermal budgets.
Implementation Method 1
This design significantly reduces stress on the silicon nitride passivation layer by eliminating the triple point
Data Source
AI summary
A semiconductor device includes a passivation layer over a dielectric layer, a via through the passivation layer and the dielectric layer, an interconnection metallization arranged over said at least one via; said passivation layer underlying peripheral portions of said interconnection metallization, and an outer surface coating that coats said interconnection metallization. The coating preferably includes at least one of a nickel or nickel alloy layer and a noble metal layer. The passivation layer is separated from the peripheral portion of the interconnection metallization by a diffusion barrier layer, preferably a titanium or a titanium alloy barrier. The device includes a dielectric layer arranged between the passivation layer and the diffusion barrier layer; and a hollow recess area between the passivation layer and the end portion of the barrier layer and between the passivation layer and the foot of the outer surface coating.