MIM Capacitor Contact Structure With Concave Plug Arcs
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Solution Overview
Problem
The challenge in semiconductor integrated circuits is to develop capacitors with small size but high capacitance, particularly in high-density memory cells, where the contact resistance between the capacitor electrode and the conductive plug remains a significant issue.
Innovation Solution
The MIM capacitor structure incorporates a design with concave arcs in the conductive plugs that reduce contact resistance by increasing the surface area through a combination of dry and wet etching processes, using aluminum-containing material layers and titanium nitride layers, followed by the formation of conductive plugs that conform to these arcs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the capacitor size is reduced to increase integration density, then the capacitance per unit area increases, but the contact resistance between electrode and conductive plug increases
Solution Approach 1:
The patent applies curvature by forming arc-shaped surfaces on the conductive plugs that are concave toward the aluminum-containing material layers. This curved geometry increases the contact surface area between the conductive plug and the electrode, thereby reducing contact resistance while maintaining the reduced capacitor size for high integration density.
Solution Approach 2:
The patent transitions from a planar contact interface to a three-dimensional arc-shaped contact surface. By introducing curvature in the vertical and lateral dimensions, the contact area is expanded without increasing the footprint area, thus reducing contact resistance while maintaining compact capacitor dimensions for high-density integration.
2Reliability
If the contact surface area is increased to reduce contact resistance, then the electrical connectivity improves, but the capacitor footprint area increases
Solution Approach 1:
The arc-shaped contact surfaces utilize vertical curvature rather than lateral expansion. The concave arcs increase the effective contact area between the conductive plug and electrode by utilizing the vertical dimension, thereby improving electrical connectivity without increasing the horizontal footprint area of the capacitor.
Solution Approach 2:
The patent solves the area conflict by moving the contact area expansion from the horizontal plane to the vertical dimension. The arc-shaped surfaces create additional contact area through vertical profiling, allowing improved electrical connectivity while maintaining a compact capacitor footprint for high-density integration.
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
This design effectively reduces contact resistance between the electrodes and conductive plugs, enhancing the performance of MIM capacitors by increasing the surface area and improving electrical connectivity.
Implementation Method 1
a wet etching is performed to etch the first aluminum-containing material layer and the second aluminum-containing material layer to form a first arc in the first aluminum-containing material layer which is concave toward the first aluminum-containing material layer
Implementation Method 2
a dry etching is performed to form a first via hole and a second via hole, the first via hole penetrates through the dielectric layer, the first extension part and the capacitor dielectric layer
Data Source
AI summary
An MIM capacitor structure includes a dielectric layer. An MIM capacitor body is disposed on the dielectric layer. The MIM capacitor body includes a first electrode and a second electrode stacked alternately and a capacitor dielectric layer disposed between the first electrode and the second electrode. The first electrode has a first extension part extending out from the MIM capacitor body. The second electrode has a second extension part extending out from the MIM capacitor body. The first extension part includes a first aluminum-containing material layer. The second extension part includes a second aluminum-containing material layer. A first conductive plug penetrates the first extension part, wherein the first conductive plug has a first arc which is concave toward the first aluminum-containing material layer. A second conductive plug penetrates the second extension part, wherein the second conductive plug has a second arc which is concave toward the second aluminum-containing material layer.