BEOL Via Across Adjacent Conductive Lines for Wider Process Window
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Solution Overview
Problem
The semiconductor industry faces challenges in scaling down integrated circuit (IC) manufacturing while maintaining complex interconnect structures, requiring innovative solutions for efficient electrical connections within the back-end-of-line (BEOL) fabrication process.
Innovation Solution
The development of an interconnect structure involving multiple conductive layers and vias, formed through various damascene processes, such as single-damascene and dual-damascene, to create efficient electrical connections between conductive lines, allowing for improved manufacturing efficiency and reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interconnect structures are used in BEOL fabrication, then manufacturing complexity increases and costs rise, but electrical performance and manufacturing yield are compromised
Solution Approach 1:
The patent divides the interconnect formation into separate stages: first forming conductive lines in a first dielectric layer, then forming vias through a second dielectric layer to access those lines. This segmentation allows each layer to be optimized independently, reducing overall manufacturing complexity while improving yield through better process control
Solution Approach 2:
The patent transitions from planar interconnect structures to three-dimensional stacked structures with conductive lines in multiple dielectric layers. By adding the vertical dimension with properly spaced vias, the design achieves improved electrical performance without proportionally increasing manufacturing complexity
2Productivity
If geometry size is scaled down to increase functional density, then production efficiency improves and costs decrease, but manufacturing complexity increases
Solution Approach 1:
The patent forms the first conductive lines and first dielectric layer before forming the second dielectric layer and vias. This preliminary action allows subsequent processing steps to be simpler and more efficient, as the foundation is already in place, thereby improving production efficiency without proportionally increasing manufacturing complexity
Solution Approach 2:
The patent applies different dielectric materials with optimized properties to different layers: the first dielectric layer uses materials optimized for planar conductor formation, while the second dielectric layer uses materials optimized for via formation and electrical isolation. This local optimization enables scaling down while maintaining manufacturing efficiency
3Reliability
If via dimensions are reduced to increase interconnect density, then electrical resistance decreases, but process window for defining interconnects narrows
Solution Approach 1:
The patent segments the via formation process into distinct steps: forming the second dielectric layer, then forming vias through it to access the first conductive lines. This segmentation allows each step to be optimized independently, enabling reduced via dimensions for lower resistance while maintaining an adequate process window through controlled processing conditions
Solution Approach 2:
The patent changes key parameters including dielectric material properties, via dimensions, and spacing between vias and conductive lines. By optimizing these parameters, the patent achieves reduced via resistance while maintaining a sufficient process window for manufacturing precision
Data Source
AI summary
A semiconductor structure and method of forming the same are provided. The semiconductor structure has a conductive structure. The semiconductor structure includes a first conductive line, a second conductive line, a third conductive line and a conductive via. The first conductive line and the second conductive line are located in a first dielectric layer and extend along a first direction. The first conductive line and the second conductive line are spaced from each other by the first dielectric layer therebetween. The third conductive line is located in a second dielectric layer and extends along a second direction. The conductive via is vertically between the first conductive line and the third conductive line, and between the second conductive line and the third conductive line. The conductive via, in a vertical direction, is overlapped with a portion of the first dielectric layer that is laterally between the first conductive line and the second conductive line.