Copper Wiring Adhesion via MnSiOx Barrier Layer
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Solution Overview
Problem
Conventional semiconductor device manufacturing methods face challenges in achieving sufficient adhesion between copper wirings and interlayer insulating films, leading to potential peeling issues before the formation of a barrier layer, which also affects the reliability of copper wiring connections in fine multi-layer structures.
Innovation Solution
A semiconductor device manufacturing method involving the formation of a thin MnSiOx barrier layer by depositing a Mn film followed by a Cu film using CVD or sputtering, and subsequent annealing to enhance adhesion and prevent peeling, while allowing for effective copper filling in wiring trenches and via holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is formed to prevent copper diffusion into the interlayer insulating film, then diffusion prevention is improved, but wiring resistance increases due to the barrier layer occupying a large ratio of the cross section in fine structures
Solution Approach 1:
The invention changes the material composition of the barrier layer from conventional refractory metals (Ta, W) to a copper-containing alloy layer with specific composition ratios (Cu: 70-95 at%, another metal: 5-30 at%). This parameter change in material composition allows the barrier layer to maintain diffusion prevention functionality while reducing its resistivity, thereby lowering wiring resistance in fine structures.
Solution Approach 2:
The invention uses a composite material approach by creating a barrier layer that is an alloy of copper with another metal (such as Mn, Al, or Mg). This composite structure combines the low resistivity of copper with the diffusion barrier properties of the alloying element, achieving both low wiring resistance and effective diffusion prevention.
2Manufacturing precision
If the barrier layer is made thin to reduce wiring resistance, then wiring resistance is reduced, but adhesion between the copper wiring and interlayer insulating film deteriorates, causing peeling
Solution Approach 1:
The invention changes the compositional parameters of the barrier layer by incorporating copper (70-95 at%) along with other metals (5-30 at% such as Mn, Al, or Mg). This specific composition ratio optimization ensures that the layer maintains sufficient adhesion to the interlayer insulating film while keeping the thickness minimal to reduce wiring resistance.
Solution Approach 2:
The copper-containing alloy layer acts as an intermediary between the copper wiring and the interlayer insulating film. It provides both adhesion promotion and diffusion barrier functionality, while its optimized composition ensures good adhesion even at minimal thickness, preventing peeling issues.
3Reliability
If a conventional barrier layer is used, then diffusion prevention is achieved, but adhesion promotion is insufficient, requiring additional adhesion layers that increase process complexity
Solution Approach 1:
The copper-containing alloy barrier layer performs multiple functions simultaneously: it acts as a diffusion barrier, an adhesion promoter, and a low-resistance conductive layer. This multi-functionality eliminates the need for separate adhesion layers, thereby simplifying the manufacturing process while maintaining reliable diffusion prevention.
Solution Approach 2:
The invention merges the functions of the barrier layer and adhesion layer into a single copper-containing alloy layer. By combining diffusion prevention and adhesion promotion capabilities in one layer, the process complexity is reduced while achieving both required functionalities.
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 ensures robust adhesion and prevents peeling of copper wirings, improving the reliability of connections and reducing wiring resistance by forming a thin, uniform barrier layer that enhances the adhesion between copper and interlayer insulating films.
Implementation Method 1
Heat treatment is performed to react Si and O as the constituent elements in the interlayer insulating film with Mn as the constituent element in the seed layer
Implementation Method 2
A barrier layer is therefore formed at the interface between a Cu wiring and the interlayer insulating film, the barrier layer being made of MnSiOx compound
Implementation Method 3
depositing a Mn film followed by a Cu film using CVD or sputtering
Implementation Method 4
depositing a Mn film followed by a Cu film using CVD or sputtering
Data Source
AI summary
A concave portion is formed in an interlayer insulating film formed on a semiconductor substrate. Then a first film of Mn is formed by CVD, the first film covering the inner surface of the concave portion and the upper surface of the insulating film. Then conductive material essentially consisting of Cu is deposited on the first film to embed the conductive material in the concave portion. Then the semiconductor substrate is annealed. During the period until a barrier layer is formed having also a function of improving tight adhesion, it is possible to ensure sufficient tight adhesion of wiring members and prevent peel-off of the wiring members.