DRAM Contact Plug Fabrication via Segmented Structure
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Solution Overview
Problem
Current DRAM units with buried gate structures face limitations in fabrication capability, affecting performance and reliability, particularly in achieving higher integration and density as electronic products miniaturize.
Innovation Solution
A method for fabricating semiconductor devices involves forming a contact structure within an insulating layer, followed by the creation of a capacitor that directly contacts the contact structure, using a series of etching and dielectric layer processes to optimize the contact and capacitor design, including the use of specific materials and gas etching techniques to define the contact and capacitor geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DRAM units with buried gate structures are used, then carrier channel length is extended to reduce capacitor leakage, but fabrication capability is limited affecting performance and reliability
Solution Approach 1:
The contact structure is segmented into a bottom portion within the insulating layer and a top portion extending above it. This segmentation allows the contact structure to serve multiple functions: providing electrical connection while enabling direct contact with the capacitor, thereby improving fabrication capability without compromising the extended carrier channel length that reduces capacitor leakage
Solution Approach 2:
The contact structure extends in the vertical dimension by having a top portion that protrudes above the insulating layer surface. This dimensional extension enables direct contact with the capacitor formed on the insulating layer, resolving the fabrication limitation while maintaining the buried gate structure's advantage of extended carrier channel length for leakage reduction
2Productivity
If DRAM units are designed for higher integration and density, then miniaturization is achieved, but fabrication capability limitations affect performance and reliability
Solution Approach 1:
Dividing the contact structure into bottom and top portions enables higher integration by allowing the capacitor to be directly formed on the insulating layer with direct contact to the contact structure. This eliminates additional fabrication steps while supporting miniaturization and higher density DRAM unit design
Solution Approach 2:
The contact structure is formed with its top portion extending above the insulating layer before the capacitor is formed. This preliminary action enables direct contact between the capacitor and contact structure, simplifying subsequent fabrication steps and improving ease of manufacture for high-density DRAM units
Data Source
AI summary
A method for fabricating a semiconductor device includes the following steps. First, a contact structure is formed in the insulating layer. Preferably, the contact structure includes a bottom portion in part of the insulating layer and a top portion on part of the bottom portion and extending to cover part of the insulating layer. Next, a dielectric layer is formed on the bottom portion and the top portion, part of the dielectric layer is removed to form a first opening exposing part of the top portion and part of the bottom portion, and a capacitor is formed in the first opening and contacting the pad portion and the contact portion directly.