MIM Capacitor Sidewall Recess Structure for Higher Breakdown Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Metal-insulator-metal (MIM) capacitors face a trade-off between low parasitic resistance for high-frequency RF circuits and high breakdown voltage for low-frequency analog circuits, with existing structures compromising on reliability due to thinner dielectric layers leading to reduced breakdown voltage.
Innovation Solution
The MIM capacitor structure incorporates a recess at the side wall of the opening extending into the interlayer dielectric layer, filled with a sidewall spacer to maintain sufficient dielectric thickness, ensuring increased breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the interlayer dielectric layer is made thinner to increase capacitance, then the capacitance of the MIM capacitor increases, but the breakdown voltage decreases leading to inferior reliability
Solution Approach 1:
The patent applies local quality by forming a recess at the side wall of the opening where the dielectric layer thickness is increased locally. This allows the central region to maintain thin dielectric thickness for high capacitance while the side wall region has increased thickness for higher breakdown voltage, thus resolving the contradiction between capacitance and reliability.
Solution Approach 2:
The patent introduces a vertical dimension variation by forming a recess that extends downward from the side wall of the opening. This creates a three-dimensional structure where the dielectric thickness varies both radially and vertically, allowing simultaneous optimization of capacitance (through overall thinness) and breakdown voltage (through localized thickness increase at critical regions).
Data Source
AI summary
Disclosed are a metal-insulator-metal (MIM) capacitor structure and a method for fabricating the structure. The MIM capacitor structure includes: a substrate; a capacitor structure comprising a bottom metal layer, an interlayer dielectric layer and a top metal layer sequentially stacked over the substrate; an opening extending downward through the top metal layer into the interlayer dielectric layer; a recess located at a side wall of the opening, and extending from a bottom of the opening downward into the interlayer dielectric layer; and a sidewall spacer located in the opening, which extends over a side wall of the top metal layer and downward into the recess so as to fill it up, wherein the interlayer dielectric layer is made of the same material as the sidewall spacer. The MIM capacitor structure and a fabricating method therefor can improve the breakdown voltage of the MIM capacitor structure.