3D Interconnect Structure for Intralayer Electromigration Resistance
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Solution Overview
Problem
Electromigration in integrated circuits (ICs) causes metal depletion or accumulation, leading to open or short circuits, which affects the reliability of IC devices over time.
Innovation Solution
The integration of elevated regions on the IC surface with conductive features and a barrier film on the sidewalls, along with a dry plasma etch process to tune surface roughness, lengthens the electromigration path and alters its direction, thereby reducing the likelihood of failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flat conductor structures are used, then manufacturing is simpler, but electromigration failure occurs sooner
Solution Approach 1:
The patent transitions from a conventional two-dimensional flat conductor structure to a three-dimensional elevated structure. The conductor is raised above the substrate surface, creating vertical sidewalls that lengthen the electromigration path. This dimensional change increases reliability by extending the mean time to failure while adding structural complexity.
Solution Approach 2:
The elevated conductor structure is segmented into distinct regions: a base portion on the substrate, vertical sidewalls, and a top surface. This segmentation allows different portions to serve different functions - the sidewalls provide electromigration protection while the top surface maintains electrical connectivity, resolving the contradiction between reliability and complexity.
2Reliability
If conductor material is increased to prevent depletion, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
Instead of increasing conductor material thickness in a single layer, the patent creates vertical sidewalls that extend the conductor path in the vertical dimension. This approach provides electromigration protection through path lengthening rather than material quantity increase, improving reliability while maintaining ease of manufacture through standard deposition techniques.
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 approach extends the time before electromigration failure occurs and potentially prevents it altogether, enhancing the product lifetime of ICs by protecting against intralayer electromigration.
Implementation Method 1
The first side is etched using a dry plasma etch to create a first surface in a first plane in the first regions and second surfaces in second regions
Data Source
AI summary
An apparatus comprises a first layer comprising a first dielectric material, and first and second regions on a first side of the first layer. The first regions comprise a first surface in a first plane, and each of the second regions comprise a second surface in a second plane spaced away from the first plane by a first distance. Sidewalls extend between the first surface and the second surfaces. The apparatus further comprises a plurality of conductive features, each conductive feature comprising a bottom surface on one of the second surfaces, and a barrier film comprising a second dielectric material that contacts the sidewalls.