Semiconductor Multilayer Wiring with Copper and Aluminum Interconnects
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Solution Overview
Problem
In semiconductor devices with multilayer wiring structures, the use of copper wiring leads to corrosion issues due to oxidation, reducing the reliability of electrical connections, and the conventional solution of using aluminum electrode pads increases manufacturing costs and steps.
Innovation Solution
A semiconductor device with a multilayer wiring structure that incorporates a copper wire, an insulating film, an aluminum wire electrically connected via a via hole, and a surface protective film with a pad opening for the aluminum wire to function as an electrode pad, utilizing a tungsten plug for connection and a barrier layer to prevent corrosion and peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Cu wiring material is used to reduce wiring resistance, then conductivity is improved, but corrosion resistance deteriorates due to oxidation
Solution Approach 1:
A Ta (tantalum-based) barrier film is introduced as an intermediary layer between the Cu wire and the insulating film. This barrier film prevents diffusion of Cu into the insulating film and protects the Cu wire from oxidation corrosion, thereby maintaining electrical connection reliability while allowing the use of high-conductivity Cu wiring material.
Solution Approach 2:
The patent employs a composite structure consisting of Cu wire embedded in a Ta barrier film, which is then embedded in the insulating film. This composite material approach combines the high conductivity of Cu with the corrosion resistance and diffusion barrier properties of Ta, resolving the contradiction between conductivity improvement and corrosion resistance.
2Object-affected harmful factors
If Al electrode pad is added to cover exposed Cu wire for corrosion protection, then corrosion resistance is improved, but manufacturing complexity increases due to additional process steps
Solution Approach 1:
The patent merges the functions of the electrode pad and the corrosion protective layer into a single Al-based structure. The Al wire serves both as the electrical connection conductor and as the corrosion-protected electrode pad, eliminating the need for separate Al electrode pad formation steps and reducing manufacturing complexity.
Solution Approach 2:
The Al wire structure is designed to perform multiple functions simultaneously: it provides electrical connection, serves as the electrode pad for external connections, and offers corrosion protection due to Al's natural oxide formation. This multi-functionality eliminates the need for additional dedicated corrosion protective layers.
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 configuration enhances the reliability of electrical connections with external portions, reduces manufacturing costs by integrating the aluminum wire as both a wiring layer and electrode pad without increasing process steps, and improves the connection reliability of copper and aluminum wires.
Implementation Method 1
a Ta (tantalum-based) barrier film for preventing diffusion of Cu into the insulating film
Implementation Method 2
Al (aluminum) which has excellent corrosion resistance
Data Source
AI summary
A semiconductor device according to the present invention has a multilayer wiring structure laminating and disposing a plurality of with sandwiching an insulating film and includes: a copper wire having copper as a main component; an insulating film formed on the copper wire; an aluminum wire having aluminum as a main component and formed on the insulating film to be electrically connected to the copper wire via a via hole formed to penetrate through the insulating film; and a surface protective film formed on the aluminum wire; and the surface protective film formed with a pad opening exposing a portion of the aluminum wire as an electrode pad for electrical connection with an external portion.