Cylindrical Capacitor Contact Structure for DRAM Leakage Reduction
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Solution Overview
Problem
The continuous miniaturization of dynamic random access memory (DRAM) leads to increased leakage phenomena between node contacts and bit lines, which existing technologies struggle to effectively address without compromising semiconductor structure volume.
Innovation Solution
A semiconductor structure and preparation method involving the formation of cylindrical capacitor contact structures between bit lines, achieved through specific masking and etching processes, which reduce corner angles and increase contact areas with active regions, thereby minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the volume of DRAM is continuously reduced for miniaturization, then the device size is reduced, but the leakage phenomenon between node contact and bit line increases
Solution Approach 1:
The patent applies spheroidality by transforming the conventional square capacitor contact structure into a cylindrical structure. This curvature eliminates corner angles that were prone to leakage, while the cylindrical shape maintains adequate contact area with the active region. The rounded geometry reduces electric field concentration at corners, thereby minimizing leakage current between the node contact and bit line in miniaturized DRAM structures.
Solution Approach 2:
The patent applies local quality by modifying only the geometry of the capacitor contact structure (making it cylindrical) while keeping other structural elements unchanged. This localized change addresses the leakage problem at the capacitor contact region without requiring comprehensive redesign of the entire DRAM structure, enabling effective leakage reduction in miniaturized devices while maintaining manufacturing feasibility.
2Object-generated harmful factors
If the capacitor contact structure is changed to cylindrical shape, then the leakage is reduced, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the cylindrical capacitor contact structure through a multi-step masking and etching process before final device assembly. The method uses preliminary mask patterns to define the cylindrical geometry, followed by controlled etching to create the curved structure. This preliminary formation of the cylindrical shape enables subsequent standard fabrication steps to proceed without modification, reducing overall process complexity despite the initial geometric transformation.
Data Source
AI summary
A preparation method of a semiconductor structure includes: providing a base; forming several bit lines arranged in parallel and at intervals on the base, which extend in a first direction; forming capacitor contact material layers between adjacent bit lines, upper surfaces of which are lower than upper surfaces of the bit lines; forming filling medium layers on the capacitor contact material layers; forming several first mask patterns arranged in parallel and at intervals on the filling medium layers and the bit lines, which extend in a second direction that intersects with the first direction; patterning the filling medium layers based on the first mask patterns to form several grooves in the filling medium layers; forming second mask patterns in the grooves; and patterning the capacitor contact material layers based on the second mask patterns to form several cylindrical capacitor contact structures arranged in parallel and at intervals.