Semiconductor Bonding Material With Metal-Wire Stress Relaxation
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Solution Overview
Problem
Existing bonding materials for semiconductor devices, such as those using copper nanowires or sintered silver nanoparticles, suffer from cracking due to high elastic modulus and differences in linear expansion coefficients, leading to reliability issues.
Innovation Solution
A bonding material comprising a stress relaxation layer made of metal wires with a predetermined length and a sintered joint layer is used to connect semiconductor elements and other components, relieving stress and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bonding material with high elastic modulus (such as copper nanowires or sintered silver nanoparticles) is used to bond semiconductor elements, then bonding strength is improved, but cracking occurs due to differences in linear expansion coefficients
Solution Approach 1:
The bonding material is segmented into multiple functional layers: a stress relaxation layer made of metal wires with length equal to or greater than the thickness of the bonding material, and a sintered joint layer. This segmentation allows the stress relaxation layer to specifically address thermal expansion stress while the sintered joint layer provides bonding strength.
Solution Approach 2:
The patent changes the physical parameters of the bonding material by incorporating metal wires with specific length characteristics (length equal to or greater than the thickness of the bonding material). This parameter change enables the wires to effectively relax stress caused by thermal expansion differences while maintaining bonding integrity.
2Reliability
If a bonding material is used to ensure strong bonding between semiconductor elements and other members, then bonding reliability is improved, but stress concentration occurs due to linear expansion coefficient differences
Solution Approach 1:
The metal wires in the stress relaxation layer act as an intermediary element between the bonding material and the semiconductor elements. These wires specifically address the stress concentration problem by relaxing thermal expansion stress, while allowing the bonding material to maintain its bonding function.
Solution Approach 2:
The bonding material is designed as a composite structure combining metal wires (for stress relaxation) and sintered joint layer (for bonding). This composite approach allows simultaneous achievement of stress relaxation and strong bonding, resolving the contradiction between bonding reliability and stress concentration.
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 solution ensures reliable bonding by relaxing stress caused by linear expansion coefficient differences, thereby improving the semiconductor device's reliability and reducing cracking.
Implementation Method 1
a stress relaxation layer made of metal wires; The metal wire has a length equal to or greater than a predetermined value in a thickness direction defined to connect the semiconductor element and the second member
Implementation Method 2
a sintered joint layer bonded to the semiconductor element or the second member
Data Source
AI summary
A semiconductor device includes: a semiconductor element as a first member; a second member connected to the semiconductor element; and a bonding material that bonds the semiconductor element and the second member. The bonding material has: a stress relaxation layer made of metal wires; and a sintered joint layer bonded to the semiconductor element or the second member. The metal wire has a length equal to or greater than a predetermined value in a thickness direction defined to connect the semiconductor element and the second member.