Conductive Via Spacer Structure for DRAM Short-Circuit Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The miniaturization of semiconductor devices has increased complexity in fabricating reliable conductive vias onto conductive lines with reduced widths, particularly in dynamic random access memory (DRAM), due to the design of storage node structures and the difficulty in achieving precise height and width ratios in dielectric structures.
Innovation Solution
A semiconductor device and method involving a conductive via with distinct width segments, where a spacer is used to enhance reliability and simplify fabrication by providing protection during the process, allowing for an enlarged width without increasing the risk of short circuits, and enabling easier formation of conductive vias with specific etching selectivity differences in dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conductive via width is enlarged to simplify fabrication, then the ease of manufacture is improved, but the risk of short circuits increases
Solution Approach 1:
The conductive via is divided into two segments with different widths: a first segment (wider) for easier fabrication and alignment, and a second segment (narrower) that connects to the conductive line to minimize short circuit risk. This segmentation allows each part to serve its specific function optimally.
Solution Approach 2:
Different portions of the conductive via have different width characteristics tailored to their functional requirements. The upper portion has a larger width for manufacturing ease, while the lower portion near the conductive line has a smaller width for reliability, creating local quality variations within the single via structure.
2Productivity
If the semiconductor device is miniaturized to increase functional density, then the productivity is improved, but the manufacturing precision required increases
Solution Approach 1:
By segmenting the conductive via into width variations, the structure accommodates miniaturization requirements while maintaining manufacturability. The segmented design allows precision control where needed (near the conductive line) while maintaining larger dimensions for easier fabrication in other regions.
Solution Approach 2:
The conductive via exhibits local quality variations with different widths at different locations, enabling the device to achieve high functional density through miniaturization while maintaining appropriate manufacturing precision only in critical regions where it is most needed.
3Reliability
If the conductive via width is reduced to maintain reliability, then the short circuit risk is reduced, but the ease of manufacture deteriorates
Solution Approach 1:
The conductive via is segmented into a wider first segment for easy fabrication and a narrower second segment for reliable connection, allowing the structure to benefit from both large and small width characteristics without the drawbacks of either extreme.
Solution Approach 2:
The conductive via implements local quality by having different widths in different regions: the upper region has larger width for manufacturing ease while the lower region has smaller width for reliability, optimizing both characteristics within a single via structure.
Data Source
AI summary
A method for fabricating a semiconductor device includes the following operations. A first dielectric layer is disposed on a device layer. A second dielectric layer is disposed on the first dielectric layer. A first opening is formed in the first dielectric layer and the second dielectric layer. A conductive line is formed in the first opening, in which an upper surface of the second dielectric layer is higher than an upper surface of the conductive line. A spacer is formed on the conductive line and in a remaining portion of the first opening, in which the spacer partially covers the conductive line. A third dielectric layer is disposed on the conductive line and the second dielectric layer. A second opening is formed in the third dielectric layer. A conductive via is formed by filling the second opening with a conductive material.