Semiconductor Terminal Geometry for Electromigration Crack Suppression
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Solution Overview
Problem
Existing semiconductor elements face issues with electromigration leading to cracks in bonding layers due to high current density, particularly in the terminals and redistribution wirings.
Innovation Solution
The semiconductor element design includes terminals with specific surface area ratios and configurations, such as inclined peripheral surfaces and recessed portions, along with intermediate layers and protective films, to distribute current density uniformly and enhance bonding strength, thereby reducing the risk of cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current density is used in terminals and redistribution wirings, then electrical conductivity and power transmission are improved, but electromigration causes cracks in bonding layers
Solution Approach 1:
The terminal is divided into multiple segments: a first terminal portion with a first cross-sectional area and a second terminal portion with a second cross-sectional area. This segmentation allows different current density distributions in different regions, reducing electromigration stress while maintaining power transmission capability.
Solution Approach 2:
Different portions of the terminal have different cross-sectional areas tailored to local requirements. The first terminal portion has a larger cross-sectional area to handle higher current density near the bonding layer, while the second terminal portion has a smaller cross-sectional area optimized for connection purposes, creating local quality variations that address electromigration selectively.
2Reliability
If terminal cross-sectional area is increased to reduce current density, then electromigration is suppressed, but device area and complexity increase
Solution Approach 1:
The terminal structure transitions from a uniform cross-section to a dynamic, variable cross-section along its length. The cross-sectional area changes continuously or in steps from the first terminal portion to the second terminal portion, optimizing current density distribution without requiring a completely complex multi-component structure.
Solution Approach 2:
The terminal merges multiple functional requirements into a single continuous structure with varying cross-sectional area. Rather than using separate components for current handling and connection, the terminal integrates both functions with optimized geometry, reducing overall device complexity while achieving electromigration 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 design effectively suppresses the occurrence of cracks in bonding layers due to electromigration, ensuring reliable electrical connections and improved durability.
Implementation Method 1
electromigration due to the current density in the terminal affects the bonding layer
Implementation Method 2
an anchoring effect for the Cu redistribution wiring is generated in the organic film
Implementation Method 3
because the affinity between the organic film and the resin film is relatively high, the adhesion of the resin film to the organic film is enhanced
Data Source
AI summary
A semiconductor element includes a main body with a semiconductor layer, an electrode located on one side of the main body in a first direction and electrically conducting to the semiconductor layer, a terminal opposite to the main body with respect to the electrode in the first direction and electrically conducting to the electrode, and a metal bonding layer electrically conducting to the terminal. The terminal includes a first surface facing a side where the electrode is located in the first direction, and an opposite second surface. The bonding layer is opposite to the first surface across the second surface. In a second direction orthogonal to the first direction, the dimension of the periphery of the first surface is not less than 40% and not greater than 60% of the dimension of the periphery of the second surface.