Image Reversal Patterning for Tapered On-Chip Interconnects
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Solution Overview
Problem
Traditional dual-damascene integration processes in semiconductor manufacturing are complex, costly, and prone to dielectric damage, leading to reliability issues and increased manufacturing costs due to the need for multiple sacrificial hardmask layers and plasma etching, which degrades the performance and yield of interconnect structures.
Innovation Solution
The use of image reversal patterning to form shaped interconnect structures with tapered profiles, eliminating the need for reactive ion etching and reducing the number of layers required, by creating a patterned and cured dielectric layer directly on a permanent antireflective coating, which simplifies the integration process and enhances electrical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional dual-damascene integration process is used with multiple sacrificial hardmask layers, then patterning and protection of interlayer dielectric can be achieved, but process complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts and eliminates the sacrificial hardmask layers from the dual-damascene process, retaining only the essential permanent antireflective coating. This removal of unnecessary components directly reduces process complexity while maintaining the core functionality of patterning and protection through the permanent ARC and tapered opening design.
Solution Approach 2:
The patent inverts the traditional approach by using a permanent antireflective coating instead of sacrificial hardmasks, and by creating tapered openings that narrow toward the top rather than maintaining uniform width. This inversion fundamentally changes the process architecture, eliminating the need for multiple hardmask deposition and removal cycles.
2Reliability
If multiple sacrificial hardmask layers are used in dual-damascene process, then dielectric protection is achieved, but manufacturing yield decreases due to defect introduction
Solution Approach 1:
The patent removes the sacrificial hardmask layers that serve as defect sources, keeping only the permanent antireflective coating. This extraction eliminates the multiple deposition and removal steps that introduce defects, thereby improving manufacturing yield while the permanent ARC and tapered structure continue to provide dielectric protection.
Solution Approach 2:
The patent replaces the disposable sacrificial hardmask layers with a permanent antireflective coating that serves its protective function without requiring removal. This eliminates the cycle of deposition and removal that creates defects, improving yield while maintaining protection through the permanent ARC and tapered opening design.
3Ease of manufacture
If chemical mechanical polishing and reactive ion etching are used in dual-damascene process, then interconnect patterning is achieved, but dielectric damage occurs reducing reliability
Solution Approach 1:
The patent replaces the mechanical and plasma-based processes (chemical mechanical polishing and reactive ion etching) with a tapered opening formation approach using permanent ARC and photoresist patterning. This substitution eliminates the dielectric damage caused by mechanical polishing and plasma etching, preserving dielectric integrity while achieving interconnect patterning through the tapered structure.
Solution Approach 2:
The patent inverts the traditional patterning approach by forming tapered openings that narrow toward the top, which inherently protects the dielectric from damage during subsequent processing. This inverted geometry, combined with permanent ARC, provides patterning capability without the need for damaging mechanical or plasma processes.
4Reliability
If many sacrificial films are used for patterning and protection, then dielectric protection is improved, but manufacturing cost increases due to additional processing steps
Solution Approach 1:
The patent extracts and eliminates the multiple sacrificial films from the process stack, retaining only the essential permanent antireflective coating. This reduction in layer count directly decreases the number of processing steps required, lowering manufacturing cost while the permanent ARC and tapered opening design maintain dielectric protection.
Solution Approach 2:
The permanent antireflective coating serves multiple functions simultaneously: it provides pattern definition, dielectric protection, and serves as the structural basis for the tapered opening formation. This multi-functionality eliminates the need for separate sacrificial films, reducing processing steps and cost while maintaining protection capability.
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 improves electrical reliability by increasing the distance between conductive regions, simplifies the integration process, reduces manufacturing costs, and minimizes dielectric damage, while maintaining the performance gains of lower dielectric constant materials.
Implementation Method 1
forming a permanent antireflective coating on a substrate
Implementation Method 2
a photoresist composition which becomes patternable upon actinic radiation and chemical amplification thereof
Implementation Method 3
a photoresist composition which becomes patternable upon actinic radiation and chemical amplification thereof
Data Source
AI summary
An interconnect structure includes a patterned and cured dielectric layer located directly on a surface of a patterned permanent antireflective coating. The patterned and cured dielectric layer and the permanent antireflective coating form shaped openings. The shaped openings include an inverse profile which narrows towards a top of the shaped openings. A conductive structure fills the shaped openings wherein the patterned and cured dielectric layer and the permanent antireflective coating each have a conductively filled region.