Semiconductor Contact Structure With Conformal Interfacial Layers
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Solution Overview
Problem
As semiconductor devices scale, the increasing aspect ratio of recesses makes it challenging to form functional layers with low thickness and high conformity in recesses, such as contact holes and trenches, which affects the formation of conductive features and their integration with surrounding structures.
Innovation Solution
A method involving the formation of a recessed structure with a conductive feature and multiple functional layers, including a first and second functional layer, and an interfacial layer formed through rapid thermal treatment, which extends along the interface between these layers, ensuring great conformity and controlled thickness, facilitating the filling of the recess with a conductive feature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the recess size is reduced to accommodate scaling, then the device density is improved, but the aspect ratio of the recess increases making it harder to form functional layers with low thickness and great conformity
Solution Approach 1:
The patent divides the functional layer formation into multiple segments: first forming a barrier layer in the recess, then forming an adhesion layer over the barrier layer. This segmentation allows each layer to be optimized independently for the high aspect ratio recess, with the barrier layer providing protection during subsequent processing and the adhesion layer ensuring proper bonding to the conductive feature.
Solution Approach 2:
The patent performs preliminary actions by forming the barrier layer and adhesion layer before filling the recess with the conductive feature. The barrier layer is formed first to protect the recess walls, followed by the adhesion layer to ensure proper bonding. This preliminary layer formation enables subsequent conductive feature filling to proceed with high conformity even in high aspect ratio recesses.
2Length of stationary object
If the functional layer thickness is reduced to maintain low thickness, then the device performance is improved, but the difficulty of forming conformal layers in high aspect ratio recesses increases
Solution Approach 1:
The patent applies local quality by giving different properties to different parts of the functional layer structure. The barrier layer has protective properties to shield the recess walls during processing, while the adhesion layer has bonding properties to ensure proper adhesion to the conductive feature. This local differentiation of layer properties enables each layer to perform its specific function effectively in the high aspect ratio recess.
Solution Approach 2:
The patent uses composite materials by combining different materials for the barrier layer and adhesion layer. The barrier layer typically uses materials with high barrier properties (such as tantalum nitride or tungsten), while the adhesion layer uses materials with good adhesion properties (such as titanium or chromium). This composite structure enables both protection and adhesion functions to be achieved simultaneously in the thin functional layer.
3Adaptability or versatility
If multiple functional layers are formed to separate conductive features, then the device functionality is improved, but the process complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing the barrier layer and adhesion layer to serve multiple purposes. The barrier layer provides both physical protection during processing and electrical barrier functionality. The adhesion layer provides both bonding function and interface protection. This multi-functionality reduces the need for additional separate layers, thereby managing process complexity while maintaining device functionality.
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 enables the formation of conformal functional layers that effectively separate the conductive feature from the recessed structure, improving the integration and performance of conductive features in semiconductor devices by ensuring high conformity and controlled thickness of the interfacial layers, thus addressing the scaling challenges.
Implementation Method 1
performing a rapid thermal treatment, to form an interfacial layer extending along an interface between the first functional layer and the second functional layer
Implementation Method 2
performing a rapid thermal treatment, to form an interfacial layer extending along an interface between the first functional layer and the second functional layer
Data Source
AI summary
A contact structure and a manufacturing method are provided. The contact structure includes a recessed structure, a conductive feature, a first functional layer, a second functional layer and an interfacial layer. The conductive feature is filled in a recess of the recessed structure. The first functional layer extends between the conductive feature and the recessed structure. The second functional layer extends between the first functional layer and the conductive feature. The interfacial extends along an interface between the first and second functional layers, and includes a first element from the first functional layer and a second element from the second functional layer.