Low-Resistance Contact Fill Using Mo Interruption Layers
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Solution Overview
Problem
Conventional semiconductor device contact formation processes often result in high resistance contacts, leading to poor connections and reduced performance, particularly due to low throughput and challenges in filling features with low resistance materials like tungsten and molybdenum.
Innovation Solution
A method involving the formation of a liner layer and an interruption layer, primarily using molybdenum, on the sidewalls and exposed surfaces of conductive layers within features in a dielectric layer, followed by filling with a conductive material to reduce resistance and enhance throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feature fill processes are used with tungsten or molybdenum, then low resistance contacts can be achieved, but throughput is very low and productivity is negatively impacted
Solution Approach 1:
The fill process is segmented into multiple deposition stages: initial liner layer formation, interruption layer formation, and subsequent fill completion. This segmentation allows optimization of each stage independently, achieving both low resistance and high throughput by controlling material deposition in controlled increments rather than attempting complete fill in a single step
Solution Approach 2:
A liner layer is formed preliminarily on the feature walls before the main fill process. This preliminary action creates a foundation that prevents defects and ensures uniform subsequent deposition, enabling faster overall processing while maintaining low resistance characteristics
2Reliability
If MEOL contacts are formed with high resistance, then the contact connection quality deteriorates, but conventional processes struggle to achieve low resistance without reducing throughput
Solution Approach 1:
The deposition parameters are changed and optimized at different stages: liner layer thickness, interruption layer composition, and fill material properties are carefully controlled. These parameter changes enable achievement of low resistance contacts while maintaining high throughput by preventing defects that would require rework
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 approach significantly reduces the resistance of conductive features and improves the throughput of the filling process, resulting in more reliable and efficient semiconductor device contacts.
Implementation Method 1
forming a liner layer on sidewalls of the feature and an exposed surface of a conductive layer within the feature... forming an interruption layer on the liner layer
Implementation Method 2
The liner layer includes molybdenum (Mo) or tungsten (W)... The interruption layer includes Mo
Data Source
AI summary
Embodiments of the disclosure include an apparatus and method of forming a semiconductor structure that includes metal contacts with a low resistance. In some embodiments, the semiconductor device generally includes an interconnect. The interconnect generally includes a dielectric layer with a tungsten (W) plug formed therein, a feature formed in the dielectric layer and over the W plug, a liner layer formed on an exposed surface of the W plug and on sidewalls of the feature, an interruption layer formed on the liner layer, and a conductive material substantially filling the feature. The liner layer includes molybdenum (Mo) or W, and the interruption layer includes Mo.