Tungsten Contact Barrier Layer for Semiconductor Devices
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Solution Overview
Problem
The continuous shrinking of IC device dimensions poses challenges in improving contact resistance and electrical performance, as existing contact structures struggle to effectively connect FEOL and BEOL components with optimal conductivity and reliability.
Innovation Solution
The formation of tungsten contact features with a tungsten barrier layer, which replaces traditional Ti/TiN barrier layers, allows for improved electrical conductivity and reduced contact resistance by avoiding contamination and allowing a larger volume of bulk tungsten, while also partially or fully filling openings to enhance contact features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Ti/TiN barrier layers are used in tungsten contact structures, then manufacturing process compatibility is maintained, but contact resistance uniformity and electrical performance deteriorate due to contamination and limited bulk tungsten volume
Solution Approach 1:
The patent removes the Ti/TiN barrier layer from the contact structure, retaining only the tungsten layer. This extraction eliminates the contamination issues and resistance uniformity problems associated with the Ti/TiN barrier layer, while still maintaining process compatibility through selective deposition techniques
Solution Approach 2:
The patent changes the deposition parameters to enable selective tungsten deposition - filling openings to different depths based on the underlying structure. By controlling deposition conditions (temperature, pressure, precursor flow), the process achieves selective filling without requiring Ti/TiN barrier layers, thereby improving contact resistance uniformity
2Length of moving object
If opening sizes are reduced to accommodate smaller IC dimensions, then device scaling is achieved, but contact resistance increases and electrical performance deteriorates
Solution Approach 1:
The patent performs preliminary selective deposition of tungsten that partially or fully fills openings before final contact formation. This preliminary action ensures that smaller openings receive adequate tungsten volume in advance, compensating for the reduced cross-sectional area and maintaining low contact resistance despite device scaling
Solution Approach 2:
The patent applies different deposition conditions to different regions - smaller openings receive more complete filling while larger openings receive partial filling. This local quality approach ensures optimal tungsten volume in each contact region, maintaining electrical conductivity across varying feature sizes
3Reliability
If bulk tungsten volume is increased to improve conductivity, then electrical performance improves, but manufacturing process complexity increases
Solution Approach 1:
The patent employs feedback control in the deposition process, monitoring the filling status of openings and adjusting deposition parameters in real-time. This feedback mechanism enables precise control of tungsten volume in each contact feature, achieving optimal conductivity without requiring overly complex manufacturing processes
Solution Approach 2:
The patent uses dynamic deposition conditions that can be adjusted during the process - changing temperature, pressure, or precursor flow rates mid-deposition to control filling behavior. This dynamic approach allows flexible control of tungsten volume to achieve desired conductivity while maintaining manufacturing simplicity
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 results in improved uniformity of contact resistance and sheet resistance, enhancing the electrical performance of semiconductor devices by up to 50% compared to traditional tungsten contacts with Ti/TiN barrier layers.
Implementation Method 1
The first tungsten contact feature is disposed over and electrically connected to the cobalt-containing conductive feature... forming a tungsten barrier layer... allows for improved electrical conductivity and reduced contact resistance by avoiding contamination
Implementation Method 2
forming a tungsten layer on the barrier layer so as to form a second tungsten contact feature in the second opening
Data Source
AI summary
A semiconductor device includes a first dielectric layer, a cobalt-containing conductive feature, a non-cobalt conductive feature, a second dielectric layer, a first tungsten contact feature, a second tungsten contact feature, and a tungsten barrier layer. The cobalt-containing conductive feature is disposed in the first dielectric layer. The non-cobalt conductive feature is disposed in the first dielectric layer, and is spaced apart from the cobalt-containing conductive feature. The second dielectric layer is disposed over the first dielectric layer. The first tungsten contact feature is disposed in the second dielectric layer, and is electrically connected to the cobalt-containing conductive feature. The second tungsten contact feature is disposed in the second dielectric layer, and is electrically connected to the non-cobalt conductive feature. The tungsten barrier layer surrounds the second tungsten contact feature, and is connected to the second tungsten contact feature, the non-cobalt conductive feature and the second dielectric layer.