Conductive Material Deposition for Fine-Pitch Line Bending Prevention
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Solution Overview
Problem
The challenge of depositing metals like ruthenium in fine pitch line/space structures without causing line bending issues due to high stress, particularly in semiconductor devices with dimensions below 20 nm, is unresolved in conventional plasma processing technologies.
Innovation Solution
A multi-step metal deposition method involving the use of a filling material to provide structural reinforcement, including selective pre-filling of recesses, patterning, and controlled etch back processes to prevent line bending, allowing metals like ruthenium to be deposited effectively in high aspect ratio features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-stress metals like ruthenium are deposited in fine pitch structures, then conductive material coverage is improved, but line bending and deformation occur
Solution Approach 1:
The filling material is deposited in advance before the conductive material to provide structural reinforcement. This preliminary action prevents line bending during subsequent conductive material deposition by maintaining the structural integrity of fine pitch features, thereby enabling complete coverage without deformation.
Solution Approach 2:
The filling material acts as an intermediary between the substrate and the conductive material. It provides mechanical support to prevent line bending while allowing the conductive material to be deposited completely, thus mediating between the need for coverage and the need to prevent deformation.
2Shape
If multiple deposition and etch back cycles are performed, then line bending is prevented, but processing time increases
Solution Approach 1:
The deposition process is segmented into multiple cycles, each depositing a portion of the conductive material followed by an etch back step. This segmentation allows controlled deposition that prevents line bending while achieving complete filling, breaking down the complex process into manageable stages.
Solution Approach 2:
The process employs periodic cycles of deposition and etch back operations. Each cycle deposits a layer and then removes excess material, repeating this pattern until complete filling is achieved. This periodic action ensures structural integrity is maintained throughout the deposition process.
3Device complexity
If conventional single-step deposition is used, then processing complexity is reduced, but line bending occurs in high aspect ratio features
Solution Approach 1:
The filling material is deposited as a preliminary layer before the conductive material to provide structural support in high aspect ratio features. This preliminary reinforcement prevents line bending during conductive material deposition, enabling conventional-looking processes to work for simple geometries while advanced multi-cycle processes handle high aspect ratio features.
Solution Approach 2:
The filling material provides localized structural reinforcement where needed in high aspect ratio features. The multi-cycle deposition process applies different qualities of deposition control to different stages, with each cycle tailored to prevent line bending in specific geometric conditions.
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 prevents line bending and deformation during metal deposition, enabling the use of high-stress metals like ruthenium in fine pitch structures, thereby enhancing the structural integrity and reliability of semiconductor devices.
Implementation Method 1
the use of a filling material to provide structural reinforcement, including selective pre-filling of recesses
Implementation Method 2
controlled etch back processes to prevent line bending
Data Source
AI summary
A method for processing a substrate that includes: depositing a filling material over the substrate including a first recess and a second recess, the filling material filling the first recess and the second recess; patterning the filling material such that the first recess is reopened while the second recess remains filled with the filling material; filling the first recess with a conductive material to a first height; etching the filling material selectively to the conductive material to reopen the second recess; filling a remainder of the first recess and the second recess with the conductive material; and performing an etch back process to etch the conductive material such that the first recess and the second recess are filled with the conductive material to a second height.