Copper Interconnection Barrier Layer via Oxygen-Contained Copper
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Solution Overview
Problem
In semiconductor devices with copper interconnections, the reliability of barrier films is compromised due to degradation in barrier ability and oxidation, especially in downsized structures, leading to increased resistance and contact resistance issues.
Innovation Solution
A method involving the formation of a barrier layer containing a refractory metal material and a second metal material that bonds with oxygen, integrated with an oxygen-contained copper layer, which reacts to form a compound layer that enhances barrier ability and adhesion between the copper interconnection layer and the insulating film, using thermal processing to self-restore the barrier layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Mn is added to the interconnection layer to form a barrier compound layer, then the barrier ability and adhesion at the interface are improved, but excessive Mn remains in the interconnection or via resulting in increased interconnection resistance and contact resistance
Solution Approach 1:
An oxygen-containing copper layer is formed before the copper interconnection layer. This preliminary oxygen source is strategically positioned to react with Mn during thermal processing, ensuring that Mn is consumed to form the barrier compound layer at the interface rather than remaining in the interconnection layer and increasing resistance.
Solution Approach 2:
The oxygen-containing copper layer acts as an intermediary that facilitates the reaction between Mn and oxygen. It provides a controlled oxygen source that enables the formation of the Mn-containing barrier compound layer while preventing excessive Mn from remaining in the interconnection layer, thus resolving the contradiction between barrier ability and resistance.
2Volume of moving object
If the interconnection trench and via-hole are downsized to improve device integration, then the semiconductor device size is reduced, but the coverage of the barrier film degrades and oxidation of the barrier film increases
Solution Approach 1:
The system uses self-restore and self-alignment mechanisms where Mn diffuses during thermal processing and automatically forms the barrier compound layer at the interface between the copper interconnection layer and the oxygen-containing copper layer. This self-organizing process ensures reliable barrier formation even in downsized structures without requiring precise manual control.
Solution Approach 2:
A composite barrier compound layer is formed containing Mn, copper, and oxygen. This composite structure provides superior barrier properties and adhesion compared to traditional single-material barrier films, enabling reliable performance in downsized interconnection trenches and via-holes.
3Reliability
If thermal processing is applied to form the barrier compound layer, then the diffusion preventing function is achieved at the interface, but excessive thermal energy may remain in the structure
Solution Approach 1:
The thermal energy applied during processing, which could be considered harmful if excessive, is converted into a beneficial effect by controlling the diffusion of Mn to form the barrier compound layer. The thermal processing is precisely controlled to enable the necessary atomic diffusion for barrier formation while avoiding excessive temperature that would cause unwanted side effects.
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 the reliability of copper interconnections by reducing resistance and contact resistance, ensuring effective barrier functionality even in degraded conditions, and efficiently consuming excess metal materials to prevent resistance increases.
Implementation Method 1
a second metal material which exhibits a diffusion preventing function for copper by bonding with oxygen
Implementation Method 2
thermal processing is made, whereby a layer having the diffusion preventing function is formed at the interface between the conductive part and the inter-layer insulating film by self-restore or self-alignment
Implementation Method 3
after forming the fourth film, forming a barrier layer containing the first metal material, the second metal material and oxygen between the insulating film and the fourth film by thermal processing
Data Source
AI summary
A first film containing a first metal material having a diffusion preventing function for copper, a second film containing oxygen-contained copper film, a third film containing copper and a second metal material which exhibits a diffusion preventing function for copper by bonding with oxygen, and a fourth film of copper as the main material are formed in an opening formed in an insulating film, and then a barrier layer containing the first metal material, the second metal material and oxygen is formed by thermal processing between the insulating film and the fourth film.