Conductive Contact Structure With Pull-Back Etch for Void-Free Fill
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in forming conductive features, such as void formation and adhesion issues, due to the use of new materials and smaller geometries, which affect the accuracy and reliability of conductive feature formation in semiconductor integrated circuits.
Innovation Solution
A method involving the formation of a barrier layer and welding layer in openings through a dielectric layer, where a pull-back etch process is performed to remove redundant structures and create a height difference, improving profile control and dimension accuracy, and allowing for the deposition of conductive material without voids by widening the openings and enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If new materials and smaller geometries are used for scaling down, then production efficiency increases and costs decrease, but void formation and adhesion issues occur in conductive features
Solution Approach 1:
The conductive feature structure is segmented into multiple functional layers: a barrier layer for adhesion and a welding layer for void prevention. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between maintaining reliability through material complexity and achieving productivity through scalable processes
Solution Approach 2:
The barrier layer acts as an intermediary between the conductive material and the substrate, providing adhesion and preventing direct contact that would cause voids. The welding layer serves as an intermediary that facilitates proper material bonding while preventing harmful interactions, thus maintaining conductive feature integrity during scaling
2Manufacturing precision
If geometry size is decreased, then functional density increases, but manufacturing precision and profile control become more difficult
Solution Approach 1:
The patent changes the physical and chemical parameters of the conductive feature formation process by introducing specific barrier and welding layers with controlled thicknesses and material properties. These parameter changes enable precise control over the conductive feature profile and dimensions, allowing high functional density to be achieved while maintaining manufacturing precision through layered structure control
3Ease of manufacture
If conventional conductive feature formation is used, then process simplicity is maintained, but void formation and adhesion issues reduce reliability
Solution Approach 1:
The barrier layer and welding layer are formed preliminarily before the main conductive material deposition. This preliminary action prepares the surface with proper adhesion properties and prevents void formation during subsequent filling processes, thereby improving reliability without significantly complicating the overall manufacturing process
Solution Approach 2:
The conductive feature structure uses composite materials consisting of the barrier layer, welding layer, and conductive material. This composite approach combines the adhesion benefits of the barrier layer with the void-prevention capabilities of the welding layer, achieving high reliability while maintaining ease of manufacture through established multi-layer deposition techniques
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 reduces void formation and improves the accuracy and reliability of conductive feature formation, particularly in small technology nodes, by ensuring better adhesion and wider process windows for conductive metal fill, thereby enhancing device performance and integrity.
Implementation Method 1
a pull-back etch process is performed to remove redundant structures
Implementation Method 2
allowing for the deposition of conductive material without voids
Implementation Method 3
enhancing adhesion
Data Source
AI summary
Generally, the present disclosure provides example embodiments relating to conductive features, such as metal contacts, vias, lines, etc., and methods for forming those conductive features. In an embodiment, a barrier layer is formed along a sidewall. A portion of the barrier layer along the sidewall is etched back by a wet etching process. After etching back the portion of the barrier layer, an underlying dielectric welding layer is exposed. A conductive material is formed along the barrier layer.