Copper Alloy Wiring Oxide Layer for Diffusion Suppression
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Solution Overview
Problem
Existing semiconductor manufacturing methods for Cu wiring struggle to effectively suppress copper atom and hole diffusion, leading to reduced electromigration resistance due to the diffusion of additive metals in the seed layer during heat treatment in an oxygen atmosphere.
Innovation Solution
A method involving the formation of a copper alloy layer with a first metal element on a semiconductor substrate, followed by a heat treatment in a non-oxidizing atmosphere to create a copper alloy metal layer, and a subsequent oxygen-containing atmosphere to form an oxide layer on the wiring surface, which enhances the suppression of copper and hole diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional diffusion-preventing films like SiCN or SiN are used, then manufacturing simplicity is maintained, but copper and hole diffusion cannot be effectively suppressed
Solution Approach 1:
The invention changes the parameter of the barrier mechanism from relying on external film materials (SiCN, SiN) to using an intrinsic oxide layer formed through controlled heat treatment in oxygen-containing atmosphere. This parameter change enables effective diffusion suppression while maintaining manufacturing simplicity by utilizing the existing copper alloy wiring structure.
2Reliability
If oxide layers are formed during heat treatment, then copper diffusion is suppressed, but the formation process becomes more complex
Solution Approach 1:
The formation of the oxide barrier layer is merged with the heat treatment process itself, eliminating the need for separate oxide formation steps. The heat treatment simultaneously serves to prevent additive metal diffusion (in non-oxidizing atmosphere) and form the oxide barrier film (in oxidizing atmosphere), reducing overall process complexity while achieving effective copper diffusion suppression.
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 oxide layer formed using this method effectively retards copper and hole diffusion, improving electromigration and stress migration resistance in copper alloy wiring compared to traditional diffusion-preventing films like SiCN or SiN.
Implementation Method 1
the oxide layer formed using this method effectively retards copper and hole diffusion, improving electromigration and stress migration resistance
Implementation Method 2
a heat treatment is performed in a non-oxidizing atmosphere to create a copper alloy metal layer
Implementation Method 3
a subsequent heat treatment in an oxygen-containing atmosphere to form an oxide layer on the wiring surface
Data Source
AI summary
A semiconductor device includes an interlayer film formed over a semiconductor substrate. A groove is formed in the interlayer film. A wiring formed in the groove is a copper alloy including copper and a metal element. An oxide layer of the metal element is formed over the surface of the wiring. The oxide layer is formed in a first region along a grain boundary of a copper crystal and a second region surrounded by the grain boundary, over the surface of the wiring. The oxide layer formed in the first region has a thickness greater than that of the oxide layer formed in the second region.