MIM Capacitor Layout With Reduced Bottom Contact Area
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Solution Overview
Problem
Integrated circuit (IC) fabrication costs are increased due to low breakdown voltage of metal-insulator-metal capacitors (MIMCAPs), which affects product yield.
Innovation Solution
The contact area between the lower metal interconnect layer and the bottom plate of MIMCAPs is reduced, using elongated or rectilinear metal interconnects that touch the bottom plate with a linewidth less than the plate's lateral area, thereby improving breakdown voltage variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact area between the lower metal interconnect layer and the bottom plate is reduced, then the breakdown voltage consistency is improved, but the manufacturing complexity increases due to the need for precise linewidth control
Solution Approach 1:
The patent applies parameter changes by modifying the contact area dimension (linewidth of metal interconnects) to optimize breakdown voltage consistency. By controlling the linewidth to be less than the plate's lateral area, the patent achieves improved reliability while managing manufacturing complexity through precise parameter specification.
2Area of stationary object
If MIMCAPs are used to achieve high capacitance density in small chip area, then the chip area is reduced, but the breakdown voltage becomes low affecting product yield
Solution Approach 1:
The patent applies local quality by creating non-uniform contact areas between the metal interconnects and the bottom plate. By making the contact area locally limited (linewidth less than plate lateral area) rather than uniform full-contact, the patent improves breakdown voltage reliability while maintaining the compact chip area advantage of MIMCAPs.
Data Source
AI summary
Integrated circuit devices, and related methods of manufacturing, that include a metal-insulator-metal capacitor (MIMCAP) in a dielectric layer over a semiconductor substrate. The MIMCAP has a top plate and a bottom plate having a lateral perimeter defining a bottom plate lateral area. A first metal interconnect layer over the MIMCAP is connected to the top plate. A second metal interconnect layer below the MIMCAP touches the bottom plate. A contact area between the second metal interconnect layer and the bottom plate is less than the bottom plate lateral area.