Metal E-Fuse Structure Design Using Dummy Patterns
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Solution Overview
Problem
The existing semiconductor fuse structures face limitations in reducing the cross-sectional area and blowing current due to the constraints on width and thickness, particularly with the width of e-Fuses being reduced to about 0.1 μm or less, and the thickness being tied to the metallization layer, which restricts further improvements.
Innovation Solution
The introduction of a local fuse region with a high pattern density, comprising a metal fuse element, contact pads, and dummy patterns in a dielectric layer, where the dummy patterns fill spaces and create a dishing effect, reducing the thickness of the metal fuse element and increasing the pattern density to below 75%, thereby reducing the cross-sectional area and required blowing current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the width and thickness of the fuse element are reduced to decrease the cross-sectional area, then the blowing current is reduced, but the fuse element becomes more difficult to manufacture with precise control
Solution Approach 1:
The patent applies local quality by creating a local fuse region with high pattern density (greater than 75%) that is distinct from the surrounding circuitry. This localized high-density region causes the metal fuse thickness to be reduced specifically in the fuse element area while maintaining standard thickness elsewhere, enabling precise control of the cross-sectional area where needed without affecting other parts of the circuit.
Solution Approach 2:
The patent changes the pattern density parameter in the local fuse region to greater than 75%, which directly causes the metal fuse thickness to decrease. This parameter change (pattern density) controls the thickness parameter of the fuse element, thereby controlling the cross-sectional area and reducing the blowing current without requiring direct manipulation of the fuse element dimensions themselves.
2Area of moving object
If the thickness of the metal fuse element is reduced below the metallization layer thickness, then the cross-sectional area is reduced, but the fuse element loses structural support and becomes difficult to form
Solution Approach 1:
The patent creates a localized high pattern density region (greater than 75%) specifically in the fuse area, which causes the metal deposition process to produce a thinner fuse element only where needed. The surrounding areas with lower pattern density maintain standard metal thickness, providing structural support and ease of manufacture for the overall circuit while the local fuse region achieves the desired thin profile.
Solution Approach 2:
The pattern density in the local fuse region acts as an intermediary that mediates between the standard metallization layer and the required thin fuse element. By controlling the pattern density to be greater than 75%, the process naturally produces a thinner metal deposit in the fuse area during standard deposition processes, eliminating the need for separate thinning steps while maintaining structural integrity.
3Use of energy by moving object
If the pattern density in the local fuse region is increased to reduce metal fuse thickness, then the blowing current is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements local quality by defining a specific local fuse region with high pattern density (greater than 75%) that is spatially separated from the rest of the circuit. This localized approach reduces blowing current by thinning the metal fuse only where needed, while the rest of the circuit maintains standard design rules and manufacturing simplicity. The high pattern density region is created using standard lithographic and deposition processes without requiring additional manufacturing steps.
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 approach allows for a significant reduction in the thickness and cross-sectional area of the metal fuse elements, resulting in lower blowing currents and enhanced manufacturing efficiency by increasing the pattern density in the local fuse regions.
Implementation Method 1
the dummy patterns fill spaces and create a dishing effect, reducing the thickness of the metal fuse element
Implementation Method 2
fuse element 2 preferably has a small cross-sectional area, so that the respective current density, hence Joule effect, is high
Implementation Method 3
passing an electrical current of a sufficient magnitude to cause electro-migration or melting
Data Source
AI summary
An integrated circuit structure is provided. The integrated circuit structure includes a semiconductor substrate; a dielectric layer over the semiconductor substrate; a metal fuse in the dielectric layer; a dummy pattern adjacent the metal fuse; and a metal line in the dielectric layer, wherein a thickness of the metal fuse is substantially less than a thickness of the metal line.