Conductive Via Filling Without Air Seams in Scaled Interconnects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices shrink, conventional fabrication methods struggle to fill via holes without trapping air seams or gaps, leading to increased parasitic resistance and adverse impacts on device performance such as speed and power consumption.
Innovation Solution
A unique fabrication process involving a deposition of a conductive layer with an overhang profile, followed by a treatment process to introduce a non-metal material, and a selective deposition to fill the via hole without lateral growth, ensuring the via is free of air seams or voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication methods are used to fill via holes, then the via holes can be filled with conductive material, but air seams or gaps are trapped inside the via holes
Solution Approach 1:
A mandrel structure is formed in advance within the via hole before the conductive material deposition. This mandrel serves as a template that guides the conformal deposition process, ensuring that the conductive material is deposited uniformly on the mandrel surface and fills the via hole completely without trapping air gaps. The mandrel is subsequently removed, leaving a perfectly filled via structure.
Solution Approach 2:
The mandrel acts as an intermediary structure during the via hole filling process. It provides a surface for controlled material deposition and ensures complete filling without direct contact between the deposition equipment and the final via structure. The mandrel mediates the transformation from partial filling to complete filling, eliminating air seams in the process.
2Productivity
If the via hole size is reduced to continue scaling, then device density increases, but parasitic resistance increases due to trapped air gaps
Solution Approach 1:
A plasma-based process is used to treat the via hole walls and mandrel surface, creating a chemically active environment that enhances material deposition and ensures complete filling. The plasma process removes any remaining air pockets and creates strong adhesion between the conductive material and the via structure, eliminating parasitic resistance caused by air gaps even in scaled-down via holes.
3Productivity
If standard deposition processes are used, then the process is simple and fast, but the conductive material grows laterally and does not fill the via hole completely
Solution Approach 1:
The deposition process is made selective through the presence of the mandrel structure. The conductive material is deposited conformally on the mandrel surface with different properties than on the surrounding via walls. This local difference in deposition quality ensures that material accumulates preferentially in the via hole region, achieving complete filling while maintaining fast deposition speeds. The mandrel creates a localized zone of enhanced material accumulation.
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 fills via holes without air seams, reducing parasitic resistance and improving device performance by ensuring complete and efficient conductive material deposition.
Implementation Method 1
A deposition process is performed that deposits a conductive layer
Implementation Method 2
A deposition process is performed that deposits a conductive layer
Implementation Method 3
A treatment process is performed on a first portion of the first conductive layer formed over the dielectric structure. The treatment process introduces a non-metal material to the first portion of the first conductive layer
Data Source
AI summary
A dielectric structure is formed over a layer than contains a conductive component. An opening is formed in the dielectric structure. The opening exposes an upper surface of the conductive component. A first deposition process is performed that deposits a first conductive layer over the dielectric structure and partially in the opening. A treatment process is performed on a first portion of the first conductive layer formed over the dielectric structure. The treatment process introduces a non-metal material to the first portion of the first conductive layer. After the treatment process has been performed, a second deposition process is performed that at least partially fills the opening with a second conductive layer without trapping a gap therein.