Semiconductor Memory Element Dummy Pattern for Gate Uniformity
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Solution Overview
Problem
As semiconductor memory elements become highly integrated, the miniaturization of circuit patterns leads to challenges in maintaining uniformity and reliability of buried gate electrodes, particularly due to the short channel effect, which degrades electrical characteristics and increases leakage current.
Innovation Solution
The introduction of a dummy pattern in the peripheral circuit region using a buried channel array transistor (BCAT) structure enhances metal etch back dispersion characteristics of gate patterns in the memory cell region by ensuring consistent lengths and uniform contact areas between gate electrodes and conductive vias, thereby improving resistance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If circuit patterns are miniaturized to increase integration density, then productivity and integration level are improved, but manufacturing precision and reliability of buried gate electrodes deteriorate due to short channel effects
Solution Approach 1:
The patent applies preliminary action by forming dummy gate patterns in the peripheral circuit region before the metal etch back process. These dummy patterns pre-establish the etching environment and conditions, ensuring that when the actual gate electrodes undergo metal etch back, the process conditions are already optimized and uniform, thereby improving manufacturing precision without sacrificing integration density
Solution Approach 2:
The patent applies local quality by creating different structures in different regions: the memory cell region contains actual active gate electrodes, while the peripheral circuit region contains dummy gate patterns with specific structures. This local differentiation allows the dummy regions to provide localized etching control that improves the overall uniformity of gate electrode formation across the entire substrate
2Device complexity
If metal etch back process is used to form buried gate electrodes, then device complexity is reduced, but manufacturing precision deteriorates due to poor dispersion characteristics leading to non-uniform gate electrodes
Solution Approach 1:
The patent applies homogeneity by ensuring that both the dummy gate patterns in the peripheral region and the actual gate electrodes in the memory cell region undergo the same metal etch back process with identical process conditions. The dummy patterns are designed to have the same metal layer structure, ensuring uniform etching behavior and dispersion characteristics across the entire substrate, which directly improves the uniformity of gate electrode formation
3Manufacturing precision
If dummy patterns are added in the peripheral circuit region, then manufacturing precision of gate patterns is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the dummy gate patterns to have the same structural characteristics as the actual gate electrodes, including the same metal layers and etching process requirements. This allows the dummy patterns to serve multiple functions: they provide etching control, establish process uniformity, and can potentially serve as additional functional elements, thereby improving manufacturing precision without proportionally increasing device complexity
Data Source
AI summary
A semiconductor memory element is provided. The semiconductor memory element includes a substrate including a memory cell region and a peripheral circuit region, an active region located in the memory cell region, a gate pattern buried in the active region, a conductive line disposed on the gate pattern, a first region including a plurality of peripheral elements placed in the peripheral circuit region, a dummy pattern buried in the peripheral circuit region, and a second region which includes the dummy pattern and does not overlap the first region.