Low-k Bit Line Spacer Structure for Capacitance and Diffusion Control
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Solution Overview
Problem
As semiconductor devices become more integrated, parasitic capacitance increases, leading to performance deterioration and device degradation due to carbon diffusion.
Innovation Solution
A semiconductor device design featuring a bit line structure with a diffusion barrier layer and low-k spacers, including a nitride-low k (NK) structure and a low-k-oxide-nitride (KON) structure to prevent impurity diffusion and reduce parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If insulating material is formed between neighboring pattern structures to reduce parasitic capacitance, then parasitic capacitance decreases, but device complexity increases due to additional spacer structures
Solution Approach 1:
The spacer structure is divided into multiple segments: a lower spacer structure with diffusion barrier layer and first low-k layer, and an upper spacer structure with second low-k layer. This segmentation allows different regions to serve different functions - the lower portion prevents carbon diffusion while the upper portion reduces parasitic capacitance, resolving the contradiction between reducing harmful effects and maintaining structural simplicity
Solution Approach 2:
Different materials are applied to different locations of the spacer structure. The diffusion barrier layer is placed at the lower portion where carbon diffusion prevention is critical, while low-k materials are applied at the upper portion where parasitic capacitance reduction is most effective. This local differentiation optimizes both functions without requiring complete structural redesign
2Reliability
If diffusion barrier layer and low-k layers are stacked to prevent carbon diffusion, then device reliability improves, but manufacturing precision requirements increase
Solution Approach 1:
The diffusion barrier layer is formed as a preliminary layer before depositing the low-k layers. This preliminary action ensures that the barrier is already in place to prevent carbon diffusion during subsequent processing steps, while the sequential deposition process maintains manageable precision requirements for each individual layer
Solution Approach 2:
The spacer structure uses a composite of multiple materials (diffusion barrier layer material and low-k material) stacked together. This composite approach allows each material to perform its specialized function - the barrier layer for diffusion prevention and the low-k material for capacitance reduction - while the layering process can be controlled within standard manufacturing precision capabilities
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 design effectively prevents carbon diffusion and minimizes parasitic capacitance, thereby enhancing device performance and reliability.
Implementation Method 1
a lower spacer structure including a diffusion barrier layer and a first low-k layer sequentially stacked over both sidewalls of the bit line contact plug
Implementation Method 2
an insulating material is formed between neighboring pattern structures... parasitic capacitance increases
Data Source
AI summary
Embodiments of present invention provide a semiconductor device capable of reducing parasitic capacitance between neighboring pattern structures and a method for fabricating the same. Also, embodiments of the present invention provide a semiconductor device capable of preventing device deterioration due to carbon diffusion and a method for fabricating the same. According to an embodiment of the present invention, a semiconductor device comprises a bit line structure including a bit line contact plug and a bit line stacked over a substrate; a lower spacer structure including a diffusion barrier layer and a first low-k layer sequentially stacked over both sidewalls of the bit line contact plug; and an upper spacer structure including a second low-k layer over both sidewalk of the bit line.