Via Interconnect Abutting Metal Line Lateral Ends
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Solution Overview
Problem
Conventional semiconductor via interconnect structures are costly and time-consuming to form, as they require electrical connections between metal lines to be established after each metal level is formed, and they often misalign, contacting both top surfaces and lateral ends of metal lines.
Innovation Solution
The formation of via interconnect structures is delayed until after the desired number of metal levels are formed, with the structures abutting lateral ends of metal lines, allowing for customized electrical connections by etching via openings and filling them with metal and/or insulator, ensuring complete contact with the periphery of metal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via interconnect structures are formed using conventional damascene process after each metal level, then electrical connections between metal lines can be established, but the manufacturing process becomes time-consuming and costly
Solution Approach 1:
The via openings are formed and metal is deposited in advance before all metal levels are completely formed. This preliminary action allows multiple via interconnect structures to be prepared simultaneously, eliminating the need to perform damascene processes repeatedly after each metal level formation, thus significantly improving manufacturing efficiency while maintaining connection reliability
Solution Approach 2:
Multiple via interconnect structures are formed and filled in a single manufacturing step rather than sequentially. By merging the formation of multiple via structures into one operation, the overall process time is reduced and manufacturing efficiency is improved without compromising the electrical connection quality
2Reliability
If via interconnect structures contact top surfaces of metal lines, then electrical connections can be established, but misalignment occurs and contact with lateral ends is incomplete
Solution Approach 1:
Instead of forming via openings that contact the top surfaces of metal lines, the invention inverts the approach by forming via openings that contact the lateral ends (sidewalls) of metal lines. This inversion eliminates misalignment issues between via centers and metal line centers, as the via openings are positioned at the ends where alignment is more tolerant and can be achieved through self-alignment mechanisms
Solution Approach 2:
A mandrel structure is introduced as an intermediary element to facilitate precise positioning of via openings at the lateral ends of metal lines. The mandrel serves as a reference structure that enables accurate alignment without requiring direct positioning between via openings and metal lines, thereby improving manufacturing precision
Data Source
AI summary
The disclosure is directed to an integrated circuit structure and methods of forming the same. The integrated circuit structure may include: a first metal level including a first metal line within a first dielectric layer; a second metal level including a second metal line in a second dielectric layer, the second metal level being over the first metal level; a first via interconnect structure extending through the first metal level and through the second metal level, wherein the first via interconnect structure abuts a first lateral of the first metal line and a first lateral end of the second metal line, and wherein the first via interconnect structure is a vertically uniform structure and includes a first metal.