AgSn Alloy Protection Layer for Electromigration Resistance
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Solution Overview
Problem
The increasing current densities through connection terminals in semiconductor devices lead to electromigration, causing resistance increases and potential wiring disconnections, which existing technologies fail to adequately prevent without increasing the size of the semiconductor device.
Innovation Solution
A protection layer made of a chemically stable AgSn alloy is applied to the surfaces of connection terminals, reducing the likelihood of electromigration by minimizing the diffusion of Cu and Ni atoms, and the use of an SnAg solder further suppresses wiring disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of connection terminals is increased to improve performance and integration, then the electrical connection capability is improved, but the size of connection terminals must be reduced which leads to increased current density and electromigration
Solution Approach 1:
The patent changes the material composition parameter of the connection terminal surface by forming an AgSn alloy layer with specific composition (Ag: 70-95 wt%, Sn: 5-30 wt%). This material parameter change reduces electromigration effects and stabilizes resistance under high current density conditions, resolving the contradiction between increased connection capability and maintained reliability
Solution Approach 2:
The patent uses a composite structure consisting of a base metal layer (Cu or Ni) combined with an AgSn alloy surface layer. This composite material structure leverages the high conductivity of Cu/Ni while utilizing the electromigration resistance of AgSn alloy, thereby maintaining both electrical performance and reliability under reduced terminal size conditions
2Volume of moving object
If the current density through connection terminals is increased to maintain terminal size, then the device size is kept small, but electromigration causes resistance increases and potential wiring disconnections
Solution Approach 1:
The patent modifies the surface material parameters by creating an AgSn alloy layer with optimized composition ratios. This parameter change fundamentally alters the electromigration characteristics of the connection terminal, enabling it to withstand high current densities without resistance increase or wiring disconnection, thus maintaining connection stability in miniaturized terminals
Solution Approach 2:
The patent applies a localized AgSn alloy layer only on the surface of the connection terminal where current flow and electromigration effects are most critical. This local quality enhancement protects the critical interface region while maintaining the overall terminal size, resolving the contradiction between miniaturization and connection reliability
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 AgSn protection layer effectively prevents electromigration, extending the lifespan of connections by three to six times compared to unprotected terminals, thereby enhancing the reliability of the junction between electronic components and circuit boards.
Implementation Method 1
The increasing current densities through connection terminals in semiconductor devices lead to electromigration, causing resistance increases and potential wiring disconnections
Implementation Method 2
reducing the likelihood of electromigration by minimizing the diffusion of Cu and Ni atoms
Implementation Method 3
solder bonding a connection terminal of the electronic component to a connection terminal of the circuit board
Data Source
AI summary
A surface of at least one of a connection terminal of an electronic component and a connection terminal of a circuit board is covered with a protection layer made of a AgSn alloy. The connection terminal of the electronic component is soldered to the connection terminal of the circuit board.