Au-Sn-Co Die Attach Composition for Suppressing IMC Growth
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Solution Overview
Problem
Existing die-attach materials for wide bandgap semiconductor devices, such as Au—Sn eutectic alloys, suffer from excessive intermetallic compound (IMC) growth, which degrades the thermal and mechanical reliability of the semiconductor device package.
Innovation Solution
A ternary die-attach material system comprising gold (Au), tin (Sn), and cobalt (Co) is introduced, with a cobalt concentration ranging from 0.01% to 0.5% by weight, which suppresses the overgrowth of IMCs and enhances the mechanical stability and reliability of the semiconductor device package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Au-Sn eutectic alloy is used as die-attach material, then good thermal and electrical connection is achieved, but excessive intermetallic compound growth occurs which degrades reliability
Solution Approach 1:
The patent modifies the chemical composition parameters of the die-attach material by adding cobalt to the Au-Sn eutectic alloy system, creating a ternary Au-Sn-Co alloy. This parameter change suppresses excessive intermetallic compound growth while maintaining the eutectic melting point and thermal-electrical conductivity, thereby resolving the contradiction between connection reliability and compositional stability.
Solution Approach 2:
The patent creates a composite die-attach material by combining Au-Sn eutectic alloy with cobalt additives. The resulting ternary composite material leverages the low melting point and good conductivity of Au-Sn while incorporating cobalt to control IMC formation, achieving both reliable thermal-electrical connection and suppressed intermetallic growth.
2Ease of manufacture
If conventional die-attach materials are used, then manufacturing process is simple, but mechanical stability and shear strength are insufficient at elevated temperatures
Solution Approach 1:
The patent enhances the mechanical properties of the die-attach material by adjusting its chemical composition to include cobalt in the Au-Sn system. This parameter modification increases shear strength and mechanical stability at elevated temperatures while maintaining compatibility with existing eutectic bonding manufacturing processes.
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 Au—Sn—Co die-attach material significantly improves the mechanical stability and reliability of the semiconductor device package by reducing IMC growth and enhancing shear and strength properties, especially at elevated temperatures.
Implementation Method 1
A ternary die-attach material system comprising gold (Au), tin (Sn), and cobalt (Co) is introduced, with a cobalt concentration ranging from 0.01% to 0.5% by weight, which suppresses the overgrowth of IMCs
Implementation Method 2
A ternary die-attach material system comprising gold (Au), tin (Sn), and cobalt (Co) is introduced... The Au—Sn—Co die-attach material significantly improves the mechanical stability and reliability
Data Source
AI summary
Die-attach materials for semiconductor device packages are provided. In one example, a semiconductor device package includes a submount. The semiconductor device package includes a semiconductor die comprising a wide bandgap semiconductor. The semiconductor device package includes a die-attach layer between the submount and the semiconductor die. The die-attach layer comprises gold (Au), tin (Sn), and cobalt (Co).