Interconnect Spacer Structure for Lower Parasitic Capacitance
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Solution Overview
Problem
As the integration of semiconductor devices increases, signal delay and signal loss due to parasitic capacitance between conductive interconnection patterns become significant issues that existing technologies have not adequately addressed.
Innovation Solution
The use of spacer layers with a low-k dielectric material, specifically silicon boron nitride layers with a boron concentration gradient, is introduced between conductive interconnection patterns to reduce dielectric constant and improve etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interlayer insulating materials are used, then manufacturing process is simple, but parasitic capacitance between interconnections increases causing signal delay and signal loss
Solution Approach 1:
The insulating layer is segmented into multiple layers with different dielectric constants. A first insulating layer with lower dielectric constant is positioned adjacent to the interconnections, while a second insulating layer with higher dielectric constant is positioned away from the interconnections. This segmentation reduces parasitic capacitance near the interconnections without requiring complete replacement of all insulating materials, thus balancing signal quality improvement with manufacturing simplicity.
Solution Approach 2:
Different regions of the insulating structure are assigned different dielectric properties. The region closest to the interconnections uses low-k material to minimize parasitic capacitance, while regions farther away use traditional materials. This local optimization targets the specific area where parasitic capacitance has the greatest impact on signal integrity, avoiding unnecessary complexity in areas where it is less critical.
2Reliability
If low-k dielectric material is used to reduce parasitic capacitance, then signal delay and signal loss are reduced, but etching resistance of the insulating layer decreases
Solution Approach 1:
The insulating structure is divided into multiple layers with different materials optimized for different functions. The first insulating layer adjacent to interconnections uses low-k material for reduced parasitic capacitance, while the second insulating layer uses traditional high-etch-resistance material. This segmentation allows each layer to perform its specialized function without compromising the other.
Solution Approach 2:
The insulating structure employs composite material architecture combining low-k dielectric material with traditional insulating material. This composite approach leverages the low dielectric constant of the first material for signal integrity while utilizing the high etching resistance of the second material for process robustness, achieving both objectives simultaneously.
Data Source
AI summary
A semiconductor device includes a substrate having a cell area and a peripheral area, transistors in the peripheral area over the substrate, a lower interlayer insulating layer between the transistors, interconnections and a first spacer layer over the transistors and the lower interlayer insulating layer, an upper interlayer insulating layer over the interconnections and the first spacer layer. The first spacer layer is disposed between the interconnections, The first spacer layer includes a first lower spacer layer and a first upper spacer layer over the first lower spacer layer. The first lower spacer layer and the first upper spacer layer include silicon, boron, and nitrogen. A boron concentration of the first lower spacer layer is different from a boron concentration of the first upper spacer layer.