Semiconductor Air Gap Structure for Parasitic Capacitance Reduction
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Solution Overview
Problem
The complexity of semiconductor device manufacturing leads to parasitic capacitive coupling between adjacent conductive elements, resulting in unwanted resistive-capacitive (RC) delay, which hinders the performance and integration of miniaturized semiconductor devices.
Innovation Solution
A semiconductor device structure is developed with air gaps between inter-layer dielectric (ILD) layers and spacers, reducing parasitic capacitance by forming conductive plugs and spacers with an etch stop layer, and using a heat treatment process to transform energy removable materials into denser spacers, thereby creating air gaps that separate the ILD layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If semiconductor devices are miniaturized and integrated with greater functionality, then device functionality and integration are improved, but parasitic capacitive coupling between adjacent conductive elements increases causing unwanted RC delay
Solution Approach 1:
The patent introduces air gaps that segment the continuous dielectric medium into isolated regions, physically separating adjacent conductive elements. This segmentation breaks the parasitic capacitive coupling pathways while maintaining electrical connectivity through conductive plugs, thereby reducing RC delay without compromising device functionality.
Solution Approach 2:
The air gap acts as an intermediary layer between adjacent conductive elements and dielectric layers. By introducing this intermediate air region, the patent reduces the capacitive coupling that would otherwise occur through continuous dielectric material, thereby mitigating parasitic effects while preserving the structural integrity and electrical functionality of the device.
2Speed
If air gaps are introduced to reduce parasitic capacitance, then RC delay is reduced and operation speed is improved, but device structure and manufacturing process become more complex
Solution Approach 1:
The patent incorporates air gaps during the initial formation stages of the semiconductor structure, specifically during dielectric layer deposition and patterning processes. By establishing the air gap structure preliminarily rather than adding it as a separate post-processing step, the patent integrates the speed-enhancing feature into the existing manufacturing flow, thereby reducing operational complexity despite the structural enhancement.
Solution Approach 2:
The patent introduces air gaps as vertical or lateral dimensional features within the existing planar semiconductor structure. By utilizing the vertical dimension for air gap formation between stacked dielectric layers, the patent achieves three-dimensional integration that reduces parasitic capacitance without significantly increasing lateral footprint or overall device complexity.
3Object-generated harmful factors
If air gaps are introduced to reduce parasitic capacitance, then manufacturing steps and operations become more complicated, but parasitic capacitance reduction and performance improvement are achieved
Solution Approach 1:
The air gap structure is formed preliminarily during the standard dielectric layer deposition and patterning processes. By integrating air gap formation into existing manufacturing steps rather than requiring separate dedicated processes, the patent reduces the additional manufacturing complexity while achieving parasitic capacitance reduction.
Solution Approach 2:
The manufacturing process is designed to self-form air gaps through standard deposition and etching operations. The dielectric layers and conductive plugs self-organize to create air gap regions during routine processing, eliminating the need for specialized equipment or complex additional manufacturing steps, thereby maintaining ease of manufacture while achieving the desired 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
This approach reduces parasitic capacitance, enhancing operation speeds and overall device performance by minimizing RC delay and improving integration complexity.
Implementation Method 1
using a heat treatment process to transform energy removable materials into denser spacers, thereby creating air gaps that separate the ILD layers
Data Source
AI summary
The present disclosure provides a method for preparing a semiconductor structure. The method includes forming a conductive structure over a semiconductor substrate, and forming a first inter-layer dielectric (ILD) layer over the conductive structure. The method also includes forming a first spacer and a conductive plug penetrating through the first ILD layer. The conductive plug is electrically connected to the conductive structure, and the first spacer is between the first ILD layer and the conductive plug. The method further includes removing a portion of the first ILD layer to form a gap adjacent to the first spacer, and filling the gap with an energy removable material. In addition, the method includes performing a heat treatment process to transform the energy removable material into a second spacer, wherein the first spacer is separated from the first ILD layer by an air gap after the heat treatment process is performed.