Cylinder-Type Capacitor Lower Electrode Leaning Prevention
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Solution Overview
Problem
In semiconductor memory devices with cylinder-type capacitors, the design rule reduction leads to a need for preventing undesirable leaning of the capacitor lower electrode to ensure sufficient cell capacitance within a limited area.
Innovation Solution
The semiconductor memory device incorporates a structure with parallel supports and capacitor lower electrodes arranged in rows, featuring support contact surfaces that contact adjacent supports, with the electrodes disposed between bit and word lines, and directly on buried contacts, using materials like metal and metal nitride to maintain a distance from the substrate and prevent leaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the design rule is reduced to increase integration density, then the area is reduced, but the capacitor lower electrode may lean due to insufficient structural support
Solution Approach 1:
The support structure is segmented into multiple discrete supports arranged in a grid pattern, with each support providing localized stabilization to capacitor lower electrodes in its vicinity. This segmentation allows the structure to maintain stability while accommodating reduced design rules and higher integration density.
Solution Approach 2:
The support structure acts as an intermediary element between the substrate and the capacitor lower electrodes. These supports provide mechanical stabilization to the capacitor lower electrodes without directly becoming part of the electrode structure itself, thus preventing leaning while maintaining the electrode's functional integrity.
2Quantity of substance
If the capacitor lower electrode height is increased to secure sufficient cell capacitance, then the capacitance is improved, but the electrode becomes more prone to leaning
Solution Approach 1:
The support structure functions as a counterbalancing system that opposes the gravitational and mechanical forces causing the capacitor lower electrode to lean. By positioning supports at strategic locations around each electrode, the structure provides counteracting forces that maintain vertical alignment even as electrode height increases to provide sufficient capacitance.
Solution Approach 2:
The support structure is formed prior to forming the capacitor lower electrodes, establishing a pre-existing framework that guides and constrains electrode formation. This preliminary action ensures that as electrodes grow in height, they are continuously supported and prevented from leaning from the outset.
3Productivity
If the design rule is reduced for higher integration, then the area per device is reduced, but the manufacturing precision required increases
Solution Approach 1:
The support structure serves multiple functions simultaneously: it provides mechanical stabilization to prevent leaning, acts as a formation mask template for electrode alignment, and defines the spatial grid for high-density integration. This multi-functionality reduces the need for separate alignment structures, thereby maintaining manufacturing precision despite reduced design rules.
Solution Approach 2:
The support structure is formed in advance as a permanent reference framework that guides subsequent electrode formation processes. This preliminary establishment of alignment references ensures that even as design rules shrink and integration density increases, the precision required for electrode placement is maintained through the pre-defined support grid.
Data Source
AI summary
A semiconductor memory device including a plurality of supports extending parallel to each other in a first direction on a semiconductor substrate, and capacitor lower electrode rows including a plurality of capacitor lower electrodes arranged in a line along the first direction between two adjacent supports from among the plurality of supports, each capacitor lower electrode including outside walls, wherein each of the capacitor lower electrodes includes two support contact surfaces on the outside walls of the capacitor lower electrode, the support contact surfaces respectively contacting the two adjacent supports from among the plurality of supports.