Stacked Gate Electrode Contacts for Dense Semiconductor Integration
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to increase the degree of integration of semiconductor devices without increasing their footprint, while ensuring reliable electrical connections between stacked gate electrodes and contact plugs.
Innovation Solution
The solution involves a semiconductor device design where multiple gate electrodes are stacked and spaced apart, with varying lengths to create contact regions. Each gate electrode has a conductive region and an insulating region, and contact plugs fill contact holes through the entire stack, connecting to the conductive regions and passing through insulating regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple gate electrodes are stacked vertically to increase integration density, then the number of elements per die increases, but the complexity of forming reliable electrical connections between contact plugs and gate electrodes increases
Solution Approach 1:
The gate electrode structure is segmented into multiple stacked gate electrodes (first gate electrode, second gate electrode, third gate electrode) with distinct conductive regions and insulating regions. This segmentation allows contact plugs to selectively connect to specific gate electrodes at different vertical levels, simplifying the connection complexity by creating discrete connection points rather than requiring complex routing through a monolithic structure.
Solution Approach 2:
The patent transitions from planar connections to three-dimensional vertical connections by stacking gate electrodes in the vertical direction. Contact plugs extend through multiple gate electrodes at different heights, utilizing the vertical dimension to establish electrical connections. This dimensional change increases integration density while providing straightforward vertical access to multiple gate levels.
2Ease of operation
If gate electrodes are extended by different lengths to provide contact regions, then contact accessibility is improved, but the manufacturing precision required for aligning contact holes with conductive regions increases
Solution Approach 1:
Conductive regions are formed on the side surfaces of gate electrodes before contact holes are etched. This preliminary formation of conductive regions ensures that when contact holes are subsequently formed and filled with contact plugs, the electrical connection is already established. This sequence reduces alignment precision requirements because the conductive regions are pre-positioned to receive contact plugs.
Solution Approach 2:
Different portions of gate electrodes are given different properties: conductive regions on side surfaces for electrical connection, and insulating regions for isolation. This local differentiation allows contact plugs to make reliable electrical contact with conductive regions while being isolated from adjacent gate electrodes by insulating regions, improving contact accessibility without requiring extreme alignment precision.
3Reliability
If contact plugs pass through multiple gate electrodes to ensure electrical connection, then connection reliability is improved, but the risk of defects during formation increases
Solution Approach 1:
Insulating regions are introduced as intermediary structures between contact plugs and gate electrodes. These insulating regions line the contact holes and provide a controlled interface between the conductive contact plug material and the conductive gate electrode regions. This intermediary layer prevents direct uncontrolled contact, reduces the risk of short circuits, and ensures reliable electrical connection while minimizing defect formation.
4Reliability
If insulating regions are disposed outside contact holes to provide isolation, then electrical isolation is improved, but the device complexity increases
Solution Approach 1:
The insulating regions are merged with the gate electrode structures, forming an integrated structure where conductive regions and insulating regions coexist on the same gate electrode bodies. This merging eliminates the need for separate isolation structures, reducing overall device complexity while maintaining effective electrical isolation between adjacent gate electrodes through the insulating regions.
Data Source
AI summary
A semiconductor device includes a vertical stack of gate electrodes. The gate electrodes extend in different lengths to provide contact regions. The gate electrodes have a conductive region and an insulating region. Contact plugs fills contact holes that pass through the stack of gate electrodes in the contact regions. The contact plugs are connected to the gate electrodes. The contact plugs pass through a conductive region of one gate electrode and are electrically connected to the one gate electrode and pass through the insulating region of other gate electrodes in the contact region. The insulating region is disposed outside of the contact holes in a region in which the gate electrodes intersect the contact plugs.