High-Aspect-Ratio Metal Lines Without Collapse in Dielectric Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor manufacturing is the collapse or deformation of high aspect ratio features during the formation of metal lines, which can lead to poor insulation and reduced reliability of semiconductor components.
Innovation Solution
A method involving two photolithography stages and two etching processes is employed to form first and second metal lines with high aspect ratios within a dielectric layer, providing mechanical support and preventing collapse or deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography resolution is increased to reduce line width and line space, then metal line dimensions are reduced, but photoresist layer thickness must be reduced which limits IC integration increase
Solution Approach 1:
The patent divides the single photolithography process into two sequential photolithography processes. The first process forms a preliminary pattern with sufficient photoresist thickness, and the second process refines the pattern to achieve the final narrow line width and line space. This segmentation allows each process to optimize for its specific purpose without compromising the other.
Solution Approach 2:
The first photolithography process performs preliminary patterning to create initial metal line structures with adequate photoresist thickness for mechanical support. This preliminary action establishes a foundation that enables the second photolithography process to achieve higher precision patterning without being constrained by photoresist thickness limitations.
2Manufacturing precision
If hard mask is used to form metal lines, then pattern definition is improved, but gap aspect ratio between metal lines increases causing void formation in insulating layer
Solution Approach 1:
The patent segments the metal line formation into two distinct stages: first forming preliminary metal lines with adequate spacing, then forming additional metal lines in the remaining gaps. This segmentation prevents the formation of high aspect ratio gaps that would cause voids, while still achieving the desired fine pitch metal line structure.
Solution Approach 2:
The first photolithography and etching process performs preliminary action by creating initial metal lines that serve as structural support. This preliminary structure reduces the effective gap depth for subsequent insulating layer deposition, preventing void formation while maintaining precise pattern definition.
3Device complexity
If single photolithography process is used to form fine pitch metal lines, then process simplicity is maintained, but collapse or deformation of high aspect ratio features occurs
Solution Approach 1:
The patent segments the metal line formation into two photolithography processes with intermediate steps. The first process creates preliminary structures that serve as mechanical support, and the second process completes the fine pitch patterning. This segmentation provides structural stability during each individual process, preventing collapse that would occur in a single high-aspect-ratio process.
Solution Approach 2:
The first photolithography process performs preliminary action by forming metal lines with sufficient structural integrity to support subsequent processing. These preliminary structures act as mechanical scaffolding that prevents collapse during the second photolithography process, enabling fine pitch features to be formed without sacrificing structural stability.
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 significantly reduces or eliminates the collapse of high aspect ratio metal lines, enhancing the reliability of semiconductor structures and increasing yield by preventing short circuits due to direct contact between semiconductor components.
Implementation Method 1
a photolithography process is performed to copy any desired element patterns or circuit patterns and transfer these patterns to layers on the surface of the wafer
Implementation Method 2
performing a first dielectric etching to form first metal line trenches in the dielectric layer; performing a second dielectric etching to form second metal line trenches between the first metal lines
Implementation Method 3
When depositing an insulating layer (e.g., silicon dioxide or other dielectric materials) by physical vapor deposition (PVD)
Implementation Method 4
followed by performing chemical-mechanical polishing (CMP) to remove the first metal over the dielectric layer; followed by performing CMP to remove the second metal over the dielectric layer
Data Source
AI summary
The present disclosure provides a method for preparing metal lines with a high aspect ratio including two photolithography stages. According to the design of the method of the present disclosure, first metal lines with high aspect ratio are formed in a dielectric layer, which provides a mechanical support to the first metal lines, thereby preventing the first metal lines from collapsing or deforming. Because of a significant reduction or elimination of collapse or deformation phenomenon in the semiconductor structure, a problem associated with short circuits due to direct contact between the semiconductor components is mitigated, and reliability of the semiconductor structures is enhanced. As a result, a yield of the semiconductor structure is increased.