Semiconductor Interconnect Structure With Insert Layer for BEOL Stability
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Solution Overview
Problem
The scaling down of integrated circuit (IC) feature sizes has led to increased complexity and challenges in forming interconnect structures during the back-end-of-line (BEOL) processes, including higher aspect ratios, resistivity, and line-to-line capacitance, which result in damages, voids, and bending during patterning and deposition processes.
Innovation Solution
The introduction of an insert layer with a higher Young's modulus than the IMD layer, inserted between the CESL and IMD or embedded within the IMD, helps strengthen the structure and reduce capacitance, mitigating issues like collapsing and bending during patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IC feature size is scaled down to increase functional density, then production efficiency and cost are improved, but interconnect structure complexity and manufacturing difficulty increase
Solution Approach 1:
The interconnect structure is segmented into multiple functional layers including IMD layer, CESL layer, and insert layer, each performing specific functions. This segmentation allows optimization of each layer independently while managing overall complexity
Solution Approach 2:
The patent employs composite material structure by introducing an insert layer with different material properties (higher Young's modulus) between the IMD and CESL layers, creating a composite structure that combines the benefits of mechanical strength and electrical insulation
2Reliability
If interconnect features are made more compact with shrinking IC feature size, then functional density is improved, but performance, yield, and cost challenges increase
Solution Approach 1:
The insert layer is introduced as a preventive measure before patterning and deposition processes to cushion and protect against the formation of damages, voids, and bending that would otherwise occur during subsequent manufacturing steps
Solution Approach 2:
The insert layer acts as an intermediary between the IMD and CESL layers, providing mechanical support and structural stability during the patterning process, thereby enabling precise formation of compact interconnect features
3Manufacturing precision
If patterning and deposition processes are performed on compact interconnect features, then interconnect density is improved, but damages, voids, and bending occur
Solution Approach 1:
The insert layer is deposited beforehand to provide mechanical support and prevent damages, voids, and bending during subsequent patterning and deposition processes
Solution Approach 2:
The insert layer with higher Young's modulus provides preliminary anti-action against the forces that would cause bending and deformation during the patterning process, counteracting these harmful effects before they can occur
4Strength
If insert layer with higher Young's modulus is added to strengthen structure, then structural stability is improved, but device complexity increases
Solution Approach 1:
The insert layer is strategically positioned only where mechanical support is needed (between IMD and CESL), providing local reinforcement without adding complexity to the entire interconnect structure
Solution Approach 2:
The composite structure of IMD-insert layer-CESL combines materials with different Young's moduli to achieve optimal structural strength while maintaining reasonable complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The addition of the insert layer improves the yield and reliability of interconnect features, reduces capacitance, and decreases RC delay in IC devices, enhancing overall performance.
Implementation Method 1
The introduction of an insert layer with a higher Young's modulus than the IMD layer, inserted between the CESL and IMD or embedded within the IMD, helps strengthen the structure
Implementation Method 2
The addition of the insert layer improves the yield and reliability of interconnect features, reduces capacitance, and decreases RC delay in IC devices
Data Source
AI summary
An interconnect structure includes an etching stop layer, a dielectric layer and an insert layer and a conductive line. The insert layer is located between the etching stop layer and the dielectric layer. The conductive line extends through the dielectric layer, the insert layer, and the etching stop layer. A material of the insert layer is different from the dielectric layer and the etching stop layer.