Curved Metal Interconnect Interfaces for Lower Contact Resistance
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Solution Overview
Problem
Forming narrow metal structures in integrated circuit devices using the damascene process can result in incomplete filling of narrow openings, leading to cavities and high contact resistance due to a small interface area between metal structures.
Innovation Solution
A subtractive patterning process is employed to form narrow metal structures with a curved upper surface, increasing the interface area and reducing contact resistance, and the metal pattern includes a contact portion that protrudes beyond or is recessed with respect to the upper surface of the insulating layer to enhance contact with adjacent metal structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the damascene process is used to form narrow metal structures, then the metal structures can be formed in the insulating layer, but the narrow openings cannot be completely filled, leading to cavities and high contact resistance
Solution Approach 1:
Instead of using a fill process (damascene) that leaves cavities in narrow openings, the patent employs a subtractive patterning process that removes excess material to form metal structures. This inverted approach—removing rather than adding material—enables complete formation of narrow metal structures without cavities, thereby eliminating the source of high contact resistance.
Solution Approach 2:
The patent changes the fundamental parameter of the formation process from additive (filling) to subtractive (removal). By using etching and patterning techniques instead of electroplating or CVD filling, the process can completely remove material to form clean, cavity-free narrow metal structures with proper interfaces, directly addressing the filling completeness issue.
2Length of moving object
If narrow metal structures are formed with small interface area, then the structure size is reduced, but the contact resistance increases
Solution Approach 1:
The patent forms metal structures with curved upper surfaces instead of flat interfaces. This curvature increases the contact area between adjacent metal structures while maintaining narrow overall dimensions. The curved surface provides better mechanical and electrical contact, reducing contact resistance without increasing the footprint or width of the metal structures.
3Reliability
If subtractive patterning process is used to form narrow metal structures, then the interface area is increased and contact resistance is reduced, but the process complexity increases
Solution Approach 1:
The patent combines multiple functions into the subtractive patterning process: forming the metal pattern, creating the curved upper surface, and establishing proper interfaces with adjacent structures all occur in a single integrated process sequence. This merging of functions reduces the need for separate processing steps that would otherwise be required to achieve each of these features individually.
Data Source
AI summary
Integrated circuit devices and methods of forming the same are provided. The methods may include providing an underlying structure including a first insulating layer and forming a first metal structure, a first adhesion pattern, and a second insulating layer thereon. The second insulating layer may be on a side surface of the first metal structure, the first metal structure may include a metal pattern and a second adhesion pattern between the first insulating layer and the metal pattern, and the first adhesion pattern contacts side surfaces of the metal pattern and the second adhesion pattern. The methods may also include forming a second metal structure on the first metal structure. The metal pattern may include a contact portion protruding upwardly beyond an upper surface of the second insulating layer or may include an upper surface recessed with respect to the upper surface of the second insulating layer.