Semiconductor Conductive Layer Stress Management
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Solution Overview
Problem
Existing semiconductor devices face challenges in managing stress and reliability, particularly when copper wires are joined, due to the high stress loads that can lead to structural warping and potential cracks in miniaturized structures with concave portions.
Innovation Solution
The semiconductor device incorporates conductive layers with materials harder than copper, such as Ti and W, between copper wires and the semiconductor chip, to distribute and reduce stress, and includes a layered structure to cancel out film stress, enhancing reliability by relaxing warp and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper wires are used for connection, then electrical conductivity is improved, but stress concentration and structural warping occur
Solution Approach 1:
The patent employs a composite conductive layer structure combining copper (high conductivity) with harder materials like tungsten or titanium nitride (high strength). The copper layer provides electrical conductivity while the harder material layer distributes stress, preventing warping and cracks in miniaturized structures with concave portions.
Solution Approach 2:
The patent modifies the physical and mechanical parameters of the conductive layers by introducing materials with different hardness and stress characteristics. The harder material layer changes the stress distribution parameter, preventing stress concentration that would otherwise occur with pure copper wiring in miniaturized devices.
2Productivity
If miniaturization is pursued, then device density is improved, but stress concentration and cracking increase
Solution Approach 1:
In miniaturized structures with concave portions, the composite conductive layer structure becomes critical. The harder material layer compensates for the increased stress concentration inherent in miniaturized designs, maintaining structural integrity while enabling higher device density.
Solution Approach 2:
The patent applies local quality enhancement by placing harder materials specifically in conductive layers where stress concentration occurs in miniaturized structures. This localized reinforcement addresses the specific vulnerability of miniaturized devices without affecting overall device density.
3Stability of the object's composition
If conductive layers are added to reduce stress, then structural stability is improved, but device complexity increases
Solution Approach 1:
The conductive layer is designed as a composite structure with specific functional分工: copper layers for conductivity and harder materials for stress distribution. This composite approach achieves structural stability while maintaining manufacturing feasibility through established semiconductor fabrication processes.
Solution Approach 2:
The conductive layers serve multiple functions simultaneously: electrical conduction, stress distribution, and structural reinforcement. This multi-functionality reduces the need for separate structural support layers, thereby limiting the increase in device complexity despite the composite structure.
Data Source
AI summary
A semiconductor device includes a semiconductor chip having a device forming surface on which a device structure is formed, a first conductive layer formed on the device forming surface of the semiconductor chip, a second conductive layer formed on the first conductive layer, a first wire that is connected to the second conductive layer and that is made of a material composed mainly of copper, and a third conductive layer that is formed between the first conductive layer and the second conductive layer and that includes a material harder than copper.