Step Interconnection Structure Using a U-Shaped Peripheral Layout
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Solution Overview
Problem
Conventional manufacturing processes for dynamic random access memory (DRAM) face challenges in optimizing the integration and quality of memory and peripheral regions, particularly in forming interconnection structures that suffer from line narrowing and line breakage due to critical bending portions in the layout pattern.
Innovation Solution
The semiconductor structure employs a U-shaped interconnection structure in the peripheral region, formed through the same process as storage node contacts in the memory region, with a U-shaped portion connecting two lateral extending portions to address bending layout patterns, eliminating the need for defining bending lines in the mask layer and enhancing process flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional interconnection structures with bending portions are formed using standard photolithography processes, then the layout flexibility is improved, but line narrowing and line breakage occur due to critical bending portions
Solution Approach 1:
The interconnection structure is divided into straight lateral extending portions and a separate U-shaped portion. The U-shaped portion is formed in an opening through the dielectric stack, while the lateral extending portions are formed on the dielectric stack surface. This segmentation eliminates critical bending portions from the photolithography process, as the U-shaped portion is defined by the opening geometry rather than mask patterns, thereby preventing line narrowing and breakage while maintaining layout flexibility.
Solution Approach 2:
The bending portion of the interconnection structure is realized in the vertical dimension by forming the U-shaped portion within an opening that extends through multiple dielectric layers. This three-dimensional approach allows the interconnection to bend without requiring critical lateral bending features in the photolithography mask, thus avoiding manufacturing precision issues while achieving the necessary layout adaptability.
2Manufacturing precision
If different manufacturing processes are used for memory region and peripheral region, then the quality of each region is optimized, but the manufacturing complexity and process integration difficulty increase
Solution Approach 1:
The same photolithography process used for forming storage node contacts in the memory region is also used for forming the interconnection structures in the peripheral region. The U-shaped portion formation methodology provides a universal approach that works for both regions, eliminating the need for separate bending line definition processes while maintaining high quality standards. This multi-functional process approach reduces manufacturing complexity while ensuring structure quality.
Data Source
AI summary
A semiconductor structure includes a substrate, a dielectric stack on the substrate, a step interconnection structure within the dielectric stack and comprising a step profile, and a dielectric isolation pattern within the step interconnection structure, wherein a top surface of the dielectric isolation pattern is coplanar with a first top surface of the step interconnection structure.