Semiconductor Copper Wiring Impurity Segmentation
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Solution Overview
Problem
Conventional copper wiring methods in semiconductor devices often fail to provide sufficient electromigration and stressmigration resistance, despite using copper which has lower electric resistance and higher electromigration resistance than aluminum.
Innovation Solution
The semiconductor device and its manufacturing method involve using copper or copper alloys for conductive plugs and wirings with different copper purities and impurity concentrations, where the conductive plugs have a lower impurity concentration than the wirings to enhance electromigration resistance and ensure sufficient stressmigration resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high purity copper is used in conductive plugs, then electromigration resistance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the copper deposition process into separate stages for conductive plugs and wirings. Different plating solutions with controlled impurity concentrations are used for each stage, allowing high purity copper to be deposited in plugs while managing overall process complexity through systematic process division and standardized manufacturing steps.
2Manufacturing precision
If different plating solutions are used for conductive plugs and wirings, then copper purity control is improved, but manufacturing time increases
Solution Approach 1:
The patent merges multiple manufacturing operations into integrated process steps. The conductive plug formation and wiring formation are combined in a sequential plating process using different solutions, and subsequent CMP processing is performed as a unified step for both components. This merging approach maintains precise copper purity control while reducing total manufacturing time through process integration.
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 effectively improves both electromigration and stressmigration resistance by preventing void formation in conductive plugs and maintaining high purity in wirings, ensuring reliable current paths and durability under heat history.
Implementation Method 1
filling a wiring made of copper or alloy mainly consisting of copper in the wiring groove by a plating method using plating solution different from plating solution to be used at the step (c)
Data Source
AI summary
A first interlayer insulating film made of insulting material is formed over an underlying substrate. A via hole is formed through the first interlayer insulating film. A conductive plug made of copper or alloy mainly consisting of copper is filled in the via hole. A second interlayer insulating film made of insulating material is formed over the first interlayer insulating film. A wiring groove is formed in the second interlayer insulating film, passing over the conductive plug and exposing the upper surface of the conductive plug. A wiring made of copper or alloy mainly consisting of copper is filled in the wiring groove. The total atom concentration of carbon, oxygen, nitrogen, sulfur and chlorine in the conductive plug is lower than the total atom concentration of carbon, oxygen, nitrogen, sulfur and chlorine in the wiring.