Semiconductor Bit Line Air Gaps for Parasitic Capacitance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices become more integrated, parasitic capacitance between conductive structures increases, deteriorating device performance, and existing methods to reduce this capacitance are limited by the high dielectric constant of materials used.
Innovation Solution
A semiconductor device is designed with strategically placed air gaps, specifically double air gaps, between conductive structures, which are formed using a method involving sacrificial spacers and capping layers, to reduce parasitic capacitance by lowering the dielectric constant effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the degree of integration of semiconductor devices is increased, then the distance between conductive structures becomes shorter and device integration is improved, but parasitic capacitance increases and performance deteriorates
Solution Approach 1:
The patent introduces air gaps (porous structures) between conductive elements including within the bit line itself. The bit line is configured with internal air gaps that create a porous configuration, reducing the dielectric constant from typical values of 3-4 down to approximately 1.0 in the air gap regions. This porous structure reduces parasitic capacitance while maintaining the integrated layout, directly resolving the contradiction between high integration and parasitic capacitance reduction.
Solution Approach 2:
The patent applies local quality by creating air gaps at specific critical locations where parasitic capacitance has the greatest impact. Air gaps are strategically positioned between adjacent conductive structures and within the bit line structure itself, rather than uniformly throughout the device. This localized application of low-dielectric constant material optimizes the balance between maintaining electrical connectivity and reducing harmful parasitic effects.
2Object-generated harmful factors
If dielectric materials with lower dielectric constant are used to reduce parasitic capacitance, then parasitic capacitance is reduced, but the dielectric materials have inherently high dielectric constant values making further reduction limited
Solution Approach 1:
The patent employs air gaps as porous structures within the bit line and between conductive elements. Air has a dielectric constant of approximately 1.0, which is the lowest possible value for a dielectric material. By creating void spaces or air-filled regions within the bit line structure and between conductive components, the patent achieves maximum dielectric constant reduction without being constrained by the limitations of solid dielectric materials.
Solution Approach 2:
The patent extracts dielectric material from critical regions to create air gaps. Instead of relying on solid dielectric materials with finite dielectric constants, the invention removes material entirely to create vacuum or air-filled spaces between conductive structures. This extraction approach eliminates the fundamental limitation of solid dielectric materials and achieves the lowest possible parasitic capacitance.
3Object-generated harmful factors
If air gaps are introduced between conductive structures to reduce parasitic capacitance, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
The patent merges the air gap formation process with existing bit line fabrication steps. The bit line structure itself is configured to include internal air gaps as an integral part of its geometry, rather than adding separate air gap structures. This integration of air gap creation into the standard bit line formation process minimizes additional fabrication complexity while achieving parasitic capacitance reduction.
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 implementation of double air gaps significantly reduces parasitic capacitance, enhancing the operation speed of semiconductor devices by effectively isolating conductive structures and improving performance.
Implementation Method 1
As the degree of integration of semiconductor devices is increased, the distance between conductive structures becomes shorter, increasing parasitic capacitance. The increase in parasitic capacitance may deteriorate performance of the semiconductor devices.
Implementation Method 2
In order to reduce parasitic capacitance, a method for lowering a dielectric constant of dielectric materials may be used. However, the method also has limitations in reducing parasitic capacitance because the dielectric materials have high dielectric constant values.
Data Source
AI summary
A semiconductor device includes: a first plug; a bit line which is in contact with the first plug and over the first plug and extended in one direction; a second plug including a first part adjacent to the bit line and a second part adjacent to the first plug; a double air gap which is disposed between the first part of the second plug and the bit line and includes a first air gap surrounding the first part of the second plug and a second air gap parallel to sidewalls of the bit line; and a capping layer suitable for capping the first and second air gaps.