Multi-Stack MIM Capacitor Layout With Spacer-Formed Via Connections
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Solution Overview
Problem
Current MIM capacitors require independent patterning of each plate, limiting thickness scaling and density, and existing three-dimensional structures face challenges in achieving high density and compatibility with packaging techniques.
Innovation Solution
A multi-stack metal-insulator-metal (MIM) structure is formed using a spacer formation process, where conductive plates are grouped into odd and even numbers, with via contacts extending vertically and isolated by dielectric spacers and metal liners, allowing for alternating lateral recesses and reduced lithography steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent patterning of each MIM plate is used, then electrical connection to each plate can be achieved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent segments the MIM capacitor structure into alternating odd and even plates that are electrically isolated from each other. This segmentation allows a single via to connect to multiple plates of the same type (all odd plates or all even plates) through lateral recesses, eliminating the need for independent patterning of each plate while maintaining reliable electrical connections.
Solution Approach 2:
The patent uses nested structures where lateral recesses are formed within the plates, and dielectric spacers are placed within these recesses. The via contacts are then nested within the structure, extending through the stack and making contact with multiple plates through the recesses. This nesting approach simplifies the overall patterning process while ensuring reliable electrical connections.
2Quantity of substance
If three-dimensional structures with pillars or trenches are used, then capacitor density increases, but thickness scaling is limited
Solution Approach 1:
The patent transitions from traditional two-dimensional parallel plate capacitors to a three-dimensional stacked structure with multiple plates arranged vertically. By utilizing the vertical dimension and creating alternating odd and even plates with lateral recesses, the design achieves high capacitor density while maintaining scalability in thickness through systematic patterning rather than relying on deep trenches or pillars.
3Manufacturing precision
If more lithography steps are used for independent plate patterning, then each plate can be precisely patterned, but manufacturing time and cost increase
Solution Approach 1:
The patent merges the patterning operations for multiple plates into a single lithography step. By designing the structure so that all odd plates and all even plates can be defined simultaneously using one lithography pattern, the method achieves precise plate patterning without requiring multiple sequential lithography steps, thereby significantly improving manufacturing throughput and reducing costs.
Data Source
AI summary
A multi-stack metal-insulator-metal (MIM) structure includes a plurality of conductive plates including a first group comprising odd-numbered ones of the plates and a second group comprising even-numbered ones of the plates. All of the conductive plates are of an identical material. A plurality of insulators are between the plurality of conductive plates; and a first plate via contact extends vertically through the plurality of conductive plates and the plurality of insulators. The first plate via contact is electrically coupled to the first group of conductive plates and electrically isolated from the second group of conductive plates. The second plate via contact extends vertically through the plurality of conductive plates and the plurality of insulators. The second plate via contact is electrically coupled to the second group of conductive plates and electrically isolated from the first group of conductive plates.