Copper Oxide Layer Corrosion Protection in Semiconductor Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reliability of semiconductor devices using copper for top metallization, bond wires, and lead frames is compromised by corrosion, which existing materials like silicon oxide and silicon nitride fail to adequately address due to brittleness and poor adhesion.
Innovation Solution
A copper oxide layer with a high content of cuprous oxide (Cu2O), between 60% and 75% copper and 25% to 40% oxygen, is formed to create a passive layer that slows down corrosion processes, providing effective corrosion protection and adhering well to copper surfaces, including wiring/pad structures and bond wires, while a dielectric structure maintains an alkaline environment to stabilize the cuprous oxide content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon oxide or silicon nitride is used as protective layer, then corrosion protection is provided, but the layer is brittle and has poor adhesion to copper
Solution Approach 1:
The patent changes the chemical composition parameters of the protective layer by specifying a copper oxide layer with 60-75 at% copper and 25-40 at% oxygen, creating a specific stoichiometric range that optimizes both protective and adhesive properties
Solution Approach 2:
The patent uses a composite approach by forming a copper oxide layer that is chemically bonded to the copper substrate, creating an integrated protective structure rather than relying on physically deposited ceramic layers
2Reliability
If copper is used for top metallization and bond wires, then electrical conductivity is improved, but corrosion resistance deteriorates
Solution Approach 1:
The patent converts the harmful oxidation of copper into a beneficial protective copper oxide layer, where the naturally occurring or controlled oxidation process creates a stable, adherent coating that protects the underlying copper from further corrosion
Solution Approach 2:
The copper oxide layer acts as an intermediary between the copper metal and the corrosive environment, serving as a protective barrier that prevents direct contact between the copper and corrosive agents while maintaining electrical functionality
3Reliability
If protective layer thickness is increased to improve corrosion protection, then corrosion resistance is improved, but mechanical ruggedness and step coverage may be compromised
Solution Approach 1:
The patent optimizes the thickness parameter of the copper oxide layer to a specific range that provides sufficient corrosion protection while maintaining mechanical integrity and adequate step coverage on the copper structure
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 copper oxide layer significantly enhances the reliability of copper structures and interconnections by providing robust corrosion protection, maintaining stability over time and facilitating the use of low-resistive copper in power semiconductor devices.
Implementation Method 1
cuprous oxide on copper forms a passive layer which significantly slows down corrosion processes that may damage the copper structure
Implementation Method 2
by the method of deposition capable of covering surfaces of arbitrary orientation to the substrate
Implementation Method 3
The alkaline environment absorbs hydrogen ions. By maintaining an alkaline pH, the alkaline environment stabilizes the cuprous oxide content of the copper oxide layer
Data Source
AI summary
A semiconductor device includes a copper structure over a semiconductor body. In a copper oxide layer on a surface of the copper structure, a content of copper is between 60 at % and 75 at % and a content of oxygen is between 25 at % and 40 at %.