Reducing Electro-Migration in Semiconductor Interconnects
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Summary
Problems
Existing interconnect structures in semiconductor ICs face challenges with electro-migration, particularly due to poor adhesion between capping barrier layers and conductive features, leading to defects like voids and hillocks, which accelerate electro-migration and degrade device performance.
Innovation solutions
A method is introduced to improve adhesion by selectively depositing an adhesion layer on the dielectric layer and annealing it to increase crystallinity, enhancing the adhesion between the capping barrier layer and the dielectric layer, thereby reducing electro-migration-related defects.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a capping barrier layer is deposited over the conductive feature and dielectric layer, then protection against electro-migration is improved, but adhesion between the capping barrier layer and dielectric layer deteriorates, leading to voids and hillocks
Why choose this principle:
An adhesion layer is introduced as an intermediary between the dielectric layer and the capping barrier layer. This adhesion layer specifically addresses the poor adhesion problem by providing a bonding interface that prevents voids and hillocks, while allowing the capping barrier layer to maintain its electro-migration protection function.
Principle concept:
If a capping barrier layer is deposited over the conductive feature and dielectric layer, then protection against electro-migration is improved, but adhesion between the capping barrier layer and dielectric layer deteriorates, leading to voids and hillocks
Why choose this principle:
The structure employs composite materials by combining the dielectric layer, adhesion layer, and capping barrier layer into a multi-layer composite structure. Each layer contributes specific properties: the dielectric layer provides insulation, the adhesion layer provides bonding strength, and the capping barrier layer provides electro-migration protection, together resolving the contradiction between protection and adhesion.
Application Domain
Data Source
AI summary:
A method is introduced to improve adhesion by selectively depositing an adhesion layer on the dielectric layer and annealing it to increase crystallinity, enhancing the adhesion between the capping barrier layer and the dielectric layer, thereby reducing electro-migration-related defects.
Abstract
The present disclosure provides a structure and a method to reduce electro-migration. An interconnect structure according to the present disclosure includes a conductive feature embedded in a dielectric layer, a capping barrier layer disposed over the conductive feature and the dielectric layer, and an adhesion layer sandwiched between the capping barrier layer and the dielectric layer. The adhesion layer includes a degree of crystallinity between about 40% and about 70%.