Stacked MIM Capacitor Module With Sidewall Spacers for Low Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MIM capacitors are expensive to build and suffer from limitations such as high serial resistance due to vertical spacing constraints between metal layers, which is unsuitable for certain applications like RF applications, and there is a need for improved MIM capacitor modules and formation processes.
Innovation Solution
A multi-capacitor module with a stacked MIM structure is developed, featuring a series of electrodes and insulators arranged vertically, with dielectric sidewall spacers to prevent capacitive coupling, allowing for construction without additional photomask layers and enabling electrical connections in series or parallel configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional MIM capacitor construction is used with additional mask layers, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the capacitor electrode formation with the existing metal interconnect layer formation process. The MIM capacitor electrodes are formed using the same metal layers and deposition processes that create the interconnect structures, eliminating the need for separate mask layers and reducing fabrication complexity while maintaining manufacturing precision
Solution Approach 2:
The metal layers serving as interconnects are given dual functionality by also serving as capacitor electrodes. The same metal deposition and patterning processes create both the interconnect pathways and the capacitor electrodes, making the fabrication process universal and reducing the number of additional steps required
2Quantity of substance
If insulator thickness is reduced to increase capacitance, then capacitance value increases, but breakdown voltage decreases
Solution Approach 1:
The patent transitions from planar capacitor geometry to a three-dimensional stacked MIM structure. By stacking multiple capacitor units vertically, the design achieves higher effective capacitance without reducing the insulator thickness of individual units, thereby maintaining breakdown voltage while increasing total capacitance through vertical stacking rather than lateral expansion
3Area of stationary object
If vertical spacing between metal layers is reduced, then device area is reduced, but serial resistance increases
Solution Approach 1:
The patent uses vertical stacking of multiple capacitor units within the available vertical space between metal layers. This three-dimensional approach increases the effective capacitor area without requiring additional lateral space or reducing the vertical spacing that would increase serial resistance, as the stacking occurs within the existing vertical envelope
4Ease of manufacture
If stacked MIM structure is used without additional photomask layers, then manufacturing cost is reduced, but manufacturing precision may deteriorate
Solution Approach 1:
The capacitor formation process is merged with the standard metal interconnect formation process. The same photomask layers used for defining interconnect patterns also define the capacitor electrode patterns, eliminating additional mask steps and reducing manufacturing cost while maintaining the precision achieved by the established interconnect fabrication process
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
The solution reduces capacitive coupling and construction costs, providing improved performance and flexibility in capacitor design, suitable for various IC structures without adding photomask layers.
Implementation Method 1
prevent or reduce capacitive coupling through the vertically-extending insulator sidewalls of the first and second cup-shaped insulators
Data Source
AI summary
A multi-capacitor module includes a stacked metal-insulator-metal (MIM) structure including a cup-shaped first electrode, a cup-shaped first insulator formed over the cup-shaped first electrode, a cup-shaped second electrode formed over the cup-shaped first insulator, a cup-shaped second insulator formed over the cup-shaped second electrode, a third electrode formed over the cup-shaped second insulator. The stacked MIM structure also includes a first sidewall spacer located between the cup-shaped first electrode and the cup-shaped second electrode, and a second sidewall spacer located between the cup-shaped second electrode and the third electrode. The cup-shaped first electrode, the cup-shaped second electrode, and the cup-shaped first insulator define a first capacitor, and the cup-shaped second electrode, the third electrode, and the cup-shaped second insulator define a second capacitor.