Semiconductor Air Gap Bit Line Structure for Parasitic Capacitance Reduction
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Solution Overview
Problem
As DRAM memory cell dimensions decrease, increased parasitic capacitance due to capacitive coupling reduces device speeds and overall performance, necessitating a solution to mitigate this issue.
Innovation Solution
A semiconductor device with spacer bit lines separated by dielectric pillars and air gaps, where the dielectric pillars and air gaps have a low dielectric constant, reducing parasitic capacitance and providing structural support to prevent bit line collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If DRAM memory cell dimensions are reduced to increase packing density, then memory storage capacity is improved, but parasitic capacitance increases and device speed decreases
Solution Approach 1:
The bit line space is segmented into multiple regions by inserting dielectric pillars between adjacent bit lines. This segmentation creates separate capacitive coupling paths and reduces the overall parasitic capacitance between bit lines, allowing faster signal transitions while maintaining high packing density
Solution Approach 2:
Air gaps with extremely low dielectric constant (k≈1) are introduced locally at critical positions where capacitive coupling occurs between bit lines and between bit lines and word lines. This local quality change significantly reduces parasitic capacitance without requiring global dimensional changes, thereby improving device speed while maintaining compact structure
2Speed
If air gaps are introduced to reduce parasitic capacitance, then device speed is improved, but structural support for bit lines is reduced
Solution Approach 1:
The structure employs a composite arrangement combining air gaps (for low parasitic capacitance) with dielectric pillars (for structural support). The dielectric pillars are positioned between bit lines to provide mechanical support preventing bit line collapse, while air gaps are positioned at capacitive coupling points to minimize parasitic capacitance. This composite approach simultaneously achieves both speed improvement and structural integrity
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
This configuration reduces parasitic capacitance, enhances device speeds, and improves overall performance by minimizing capacitive coupling and providing structural support to the bit lines.
Implementation Method 1
the dielectric pillars and air gaps have a low dielectric constant, reducing parasitic capacitance
Data Source
AI summary
The present disclosure provides a semiconductor device and a method for preparing the semiconductor device. The semiconductor device includes a plurality of spacer bit lines disposed over a substrate; a plurality of dielectric pillars disposed over the substrate, between the plurality of spacer bit lines; and a sealing dielectric layer disposed over the plurality of spacer bit lines and the plurality of dielectric pillars such that air gaps are formed between the sealing dielectric layer and the substrate.