Interconnect Structure with Low-k Reinforcing Spacers
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Solution Overview
Problem
The increasing density of metal lines in interconnect structures leads to greater RC delay due to parasitic resistance and capacitance, resulting in poor device performance.
Innovation Solution
The interconnect structure incorporates conductive elements formed in a patterned first dielectric layer, with multiple pairs of reinforcing spacers having a low dielectric constant, strategically placed between the conductive elements and the dielectric layer to reduce capacitance and RC delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If metal lines are designed to be close to each other to meet shrinkage demand, then device size is reduced, but RC delay increases due to greater parasitic resistance and capacitance
Solution Approach 1:
The patent applies local quality by introducing reinforcing spacers with low dielectric constant material specifically at critical locations between adjacent metal lines. This localized modification of dielectric properties reduces parasitic capacitance in high-density interconnect regions without requiring overall device size increase, thus resolving the contradiction between miniaturization and RC delay reduction.
Solution Approach 2:
The patent changes the dielectric constant parameter of the spacer material from conventional values to lower values (comparatively low dielectric constant). This parameter change directly reduces the capacitance between adjacent metal lines, thereby reducing RC delay while maintaining the compact metal line spacing required for small device size.
2Quantity of substance
If metal lines are densely packed to increase interconnect density, then routing capacity is improved, but capacitance between adjacent lines increases leading to greater RC delay
Solution Approach 1:
The reinforcing spacers are strategically placed between adjacent metal lines in densely packed configurations. This local modification creates low-capacitance zones specifically where high interconnect density is implemented, allowing the structure to maintain high routing capacity while reducing the harmful capacitive coupling that would otherwise result from the dense packing.
Solution Approach 2:
The reinforcing spacers act as intermediary elements between adjacent metal lines. These spacers with low dielectric constant material serve as mediators that reduce the electric field coupling between closely spaced conductors, thereby reducing parasitic capacitance and RC delay while allowing the metal lines to remain densely packed for high interconnect density.
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 use of low dielectric constant reinforcing spacers effectively reduces capacitance between adjacent metal lines, especially in densely packed configurations, thereby minimizing RC delay and enhancing device performance.
Implementation Method 1
The reinforcing spacers have a comparatively low dielectric constant, such as not greater than about 4, and are beneficial in keeping the capacitance between adjacent ones of the metal lines along the Y direction low
Data Source
AI summary
A method for manufacturing an interconnect structure includes: forming a first dielectric layer; forming a mask; patterning the first dielectric layer through the mask to form a trench, an inner surface of the trench having two first portions opposite to each other along an X direction, two second portions opposite to each other along a Y direction, and a bottom portion; forming a second dielectric layer over the mask and the patterned first dielectric layer, and along an inner surface of the trench; etching the second dielectric layer by directing an etchant in a predetermined direction such that a first part of the second dielectric layer on the two first portions and the bottom portion is removed, and a second part of the second dielectric layer on the second portions of the trench remains and is formed into two reinforcing spacers; and forming a trench-filling element.