Air Gap Formation in Semiconductor Interconnects
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Solution Overview
Problem
In semiconductor technology, air gaps in low-k dielectric materials used for interlayer dielectrics can collapse in large spacing regions, leading to performance and quality issues in integrated circuits, particularly at feature sizes below 100 nm.
Innovation Solution
A method involving the formation of an energy removable film (ERF) on the sidewalls of mask layer portions, followed by the application of a second dielectric layer and subsequent removal of the mask layer to create air gaps between conductive layer structures, which are then stabilized by a ceiling layer, reducing air gap collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air gaps are introduced in low-k dielectric materials to reduce dielectric constant, then interlayer dielectric performance is improved, but air gaps collapse in large spacing regions causing quality issues
Solution Approach 1:
The patent segments the air gap formation process by introducing energy removable films at specific locations between conductive features. Instead of creating continuous air gaps that collapse, the air gaps are segmented into controlled regions defined by the energy removable films, which act as spacers to maintain separation and prevent collapse during subsequent processing steps.
Solution Approach 2:
The energy removable films are deposited in advance before the air gap formation and collapse prevention is needed. These films are strategically placed between conductive features and remain in position during critical processing steps, preliminarily establishing the air gap structure that will later be finalized after the films are removed via energy exposure.
2Reliability
If continuous air gaps are formed in dielectric layers, then dielectric constant is reduced, but manufacturing precision deteriorates due to air gap collapse
Solution Approach 1:
The energy removable films serve as intermediary structures during the air gap formation process. These films are deposited between conductive features and act as temporary mediators that define and maintain the air gap dimensions during manufacturing. The films are later removed through energy exposure, leaving precisely controlled air gaps without collapse, thus maintaining manufacturing precision while achieving dielectric constant reduction.
3Reliability
If air gaps are used to form low-k dielectric regions, then interconnection performance is enhanced, but structural integrity deteriorates due to collapse in large spacing regions
Solution Approach 1:
The patent applies local quality by selectively placing energy removable films only in regions where air gaps are desired and where collapse risk exists. The films provide localized structural support precisely where needed between conductive features, maintaining structural integrity in critical regions while allowing air gaps to form for enhanced interconnection performance. This localized approach ensures strength is maintained where required without compromising the low-k dielectric benefits.
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 method effectively reduces air gap collapse and improves the performance of integrated circuits by maintaining air gaps within the energy removable film regions, enhancing the structural integrity and reliability of multilayer interconnections.
Implementation Method 1
applying an energy to the substrate to partially remove the energy removable films and form air gaps therefrom
Data Source
AI summary
The present disclosure provides a method for forming a semiconductor device. The method includes forming first conductive layer structures in a first dielectric layer on a substrate; forming a patterned photoresist layer having portions that are each disposed over a respective one of the first conductive layer structures; forming an energy removable film (ERF) on the sidewalls of each of the portions; forming a second dielectric layer over the ERFs, the portions of the patterned photoresist layer, and the first dielectric layer; removing the portions to leave behind a plurality of openings; filling a conductive material in the openings, the conductive material defining second conductive layer structures; forming a ceiling layer over the second conductive layer structures, the ERFs, and the second dielectric layer; and applying energy to the ERFs to partially remove the ERFs on the sidewalls of the portions thereby forming air gaps.