Tungsten MOL Interconnects Without Titanium Liner
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Solution Overview
Problem
The presence of titanium oxide between metal components in semiconductor devices increases contact resistance and leads to void formation, impairing device performance.
Innovation Solution
A semiconductor device structure and method that eliminates titanium layers by using a tungsten first metal component within an oxide layer, an interlayer dielectric with trenches, and a barrier material on the sidewalls and bottom of the trenches, allowing a second metal component to be deposited without voids, thereby reducing resistance and void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If titanium liner is used between metal components, then adhesion between metal layers is improved, but contact resistance increases and void formation occurs
Solution Approach 1:
The patent removes the titanium liner layer from the metal stack, extracting the harmful element that causes oxygen gettering and void formation. The structure transitions from having a titanium intermediate layer to being titanium-free, directly eliminating the source of the problem while maintaining adhesion through alternative means.
Solution Approach 2:
The patent introduces an oxide layer as an intermediary between the first and second metal components. This oxide layer serves as a mediating structure that prevents direct contact between metals while avoiding the oxygen gettering issues of titanium, thereby reducing void formation and contact resistance.
2Strength
If titanium layer is deposited on metal component, then adhesion is enhanced, but oxygen gettering forms titanium oxide increasing resistance
Solution Approach 1:
The patent extracts the titanium layer that causes oxygen gettering and replaces it with a titanium-free structure. By removing the titanium component entirely, the unwanted oxidation and resistance increase are eliminated while adhesion is maintained through the oxide intermediary layer.
Solution Approach 2:
The patent changes the material composition parameter by eliminating titanium and using alternative materials for the metal components and oxide layer. This parameter change fundamentally alters the chemical behavior, preventing oxygen gettering and the associated resistance problems.
3Strength
If titanium metal overhangs, then adhesion coverage is improved, but voids form in the second metal component
Solution Approach 1:
The patent removes the titanium metal that causes overhang and subsequent void formation. By eliminating the titanium layer, the mechanism that creates the overhang problem is extracted, preventing void formation in the second metal component while adhesion coverage is maintained through the oxide layer interface.
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 results in semiconductor devices with lower resistance and reduced voiding compared to prior art devices, enhancing overall performance.
Implementation Method 1
an oxide layer above the semiconductor substrate; a first metal component comprising tungsten disposed within the oxide layer
Implementation Method 2
a barrier material disposed on sidewalls and the bottom of the trench
Data Source
AI summary
Methods, apparatus, and systems for fabricating a semiconductor device comprising a semiconductor substrate; an oxide layer above the semiconductor substrate; a first metal component comprising tungsten disposed within the oxide layer; an interlayer dielectric (ILD) above the oxide layer, wherein the ILD comprises a trench and a bottom of the trench comprises at least a portion of the top of the first metal component; a barrier material disposed on sidewalls and the bottom of the trench; and a second metal component disposed in the trench.