MIM Capacitor Stepped Topography for High Density
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Solution Overview
Problem
Conventional semiconductor manufacturing technologies face challenges in creating smaller metal insulator metal capacitors (MIMcaps) with high capacitance density due to the need for additional lithography masks and processing levels, as well as limited chip area for capacitor design.
Innovation Solution
The method involves creating a stepped topography by etching either the metal or dielectric layers in semiconductor chips, allowing for the formation of MIMcaps between metal lines, which increases the effective area of capacitor plates and enhances capacitance density without requiring additional lithography masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional MIMcap designs are used to achieve high capacitor density, then capacitance density is improved, but additional lithography masks and processing levels are required
Solution Approach 1:
The patent transitions from planar capacitor plates to three-dimensional stepped capacitor plates by etching recesses into the first dielectric layer. This vertical dimensionality change allows the capacitor plates to utilize both horizontal and vertical surfaces, increasing the effective capacitance area without requiring additional lithography masks or processing levels, thereby resolving the contradiction between capacitance density and device complexity
Solution Approach 2:
The first dielectric layer is segmented by creating recesses in specific regions, allowing the formation of stepped capacitor plates. This segmentation enables the capacitor structure to be formed within the existing process flow without additional masks, achieving high capacitance density while maintaining process simplicity
2Quantity of substance
If conventional MIMcap designs are used to achieve high capacitor density, then capacitance density is improved, but chip area available for capacitors is reduced
Solution Approach 1:
By creating stepped capacitor plates that extend vertically into recesses of the first dielectric layer, the patent effectively increases the capacitance area within the same chip footprint. The vertical surfaces of the stepped structure contribute additional capacitance without consuming additional horizontal chip area, thus resolving the contradiction between capacitance density and available chip area
Solution Approach 2:
The stepped capacitor plates are formed by nesting conductive material within the recesses of the first dielectric layer. This nested structure allows the capacitor plates to occupy three-dimensional space efficiently, increasing capacitance density while minimizing the horizontal chip area required for capacitor placement
3Quantity of substance
If stepped topography is created by etching metal or dielectric layers, then capacitance density increases, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the formation of stepped dielectric recesses with the existing metal layer patterning process. By using the same lithography and etching steps that define the metal interconnect patterns to also define the dielectric recesses, the manufacturing process complexity is minimized while achieving high capacitance density through the stepped structure
Data Source
AI summary
A metal insulator metal capacitor and method for fabricating a metal insulator metal capacitor (MIMcap) are disclosed. A first level metal pattern is embedded in a first dielectric layer over a substrate. The first level metal pattern has a top surface co-planar with a top surface of the first dielectric layer. In a selected etch step, either one of the first metal pattern or the first dielectric is etched to form a stepped top surface. A conformal insulating layer on the stepped top surface. The MIMcap is formed on the conformal insulating layer in a conformal manner.