Active Gate Contact Structure With Metal Oxide Etch-Stop Isolation
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Solution Overview
Problem
Conventional semiconductor fabrication processes face challenges in forming reliable contacts over active gate structures without causing short circuits, particularly in multi-gate transistors, which limits the scalability to sub-10 nanometer nodes.
Innovation Solution
The implementation of metal oxide layers, such as HfOx, to selectively grow on exposed metal surfaces during the fabrication process, acting as an etch stop and insulating layer to prevent shorting between gate and trench contacts, allowing for direct contact formation over active gate regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fabrication processes are used to form contacts over active gate structures, then manufacturing simplicity is maintained, but short circuits occur between gate and trench contacts
Solution Approach 1:
An etch stop layer is formed prior to forming the gate contact, positioned between the gate contact and the trench contact. This preliminary structural preparation prevents short circuits during subsequent contact formation without requiring complex process modifications
Solution Approach 2:
The etch stop layer acts as an intermediary barrier between the gate contact and trench contact, physically separating them to prevent electrical shorting while allowing the fabrication process to continue with minimal complexity increases
2Productivity
If gate via size is reduced to increase density, then layout efficiency improves, but resistance increases
Solution Approach 1:
The via structure is segmented into multiple conductive layers (first conductive material and second conductive material) separated by the etch stop layer. This segmentation allows the via to maintain a larger effective cross-sectional area for lower resistance while still fitting within the required layout dimensions
3Reliability
If additional etch stops are added to prevent shorting, then short circuit prevention improves, but manufacturing complexity increases
Solution Approach 1:
The etch stop layer serves multiple functions simultaneously: it acts as an electrical barrier to prevent short circuits, provides a structural reference for subsequent etching operations, and enables via formation directly over active gate regions. This multi-functionality reduces the need for additional separate etch stop layers
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 enhances edge placement margins and reduces the risk of short circuits, enabling larger gate via CDs for lower resistance and improving layout efficiency by eliminating the need for additional etch stops, thus facilitating the fabrication of smaller and more densely packed semiconductor devices.
Implementation Method 1
The implementation of metal oxide layers, such as HfOx, to selectively grow on exposed metal surfaces during the fabrication process, acting as an etch stop and insulating layer to prevent shorting between gate and trench contacts
Data Source
Figure 1A~2A
Figure 1B~2B
Figure 3A~3B
AI summary
Contact over active gate structure with metal oxide layers are described are described. In an example, an integrated circuit structure includes a plurality of gate structures above substrate, each of the gate structures including a gate insulating layer thereon. A plurality of conductive trench contact structures is alternating with the plurality of gate structures. A portion of one of the plurality of trench contact structures has a metal oxide layer thereon. An interlayer dielectric material is over the plurality of gate structures and over the plurality of conductive trench contact structures. An opening is in the interlayer dielectric material and in a gate insulating layer of a corresponding one of the plurality of gate structures. A conductive via is in the opening, the conductive via in direct contact with the corresponding one of the plurality of gate structures, and the conductive via on the metal oxide layer.