Thermal-Sprayed Contact Layer for Crack-Resistant Semiconductor Bonding
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Solution Overview
Problem
Existing semiconductor arrangements face challenges in increasing the service life due to the high risk of damage from compressive forces during contacting, particularly with copper wire bond technology, and the rapid failure at interfaces caused by thermal cycles.
Innovation Solution
A metallic contacting element is produced by thermal spraying onto the semiconductor element, forming a textured layer with particles of copper and/or molybdenum. This textured layer distributes compressive forces and compensates for coefficient of thermal expansion mismatches, acting as a buffer layer to enhance the service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper wire bond technology is used to contact connection elements, then service life is significantly extended due to higher modulus of elasticity and electrical conductivity, but compressive forces during contacting increase resulting in risk of damage to semiconductor elements
Solution Approach 1:
A metallic contacting element is introduced as an intermediary component between the copper wire bond and the semiconductor element. This contacting element has a smaller contact area to the semiconductor element, reducing the compressive force concentration and damage risk, while still allowing the copper wire bond to provide its full mechanical and electrical benefits.
Solution Approach 2:
The contacting element is designed with different local properties: it has a larger surface area for wire bonding to copper, and a smaller, optimized contact area for interfacing with the semiconductor element. This local differentiation allows it to distribute stresses appropriately - accepting forces from the wire bond and transmitting reduced, distributed forces to the semiconductor.
2Strength
If aluminum wire bond technology is used to contact connection elements, then damage risk to semiconductor elements is reduced, but service life is limited compared to copper technology
Solution Approach 1:
The contacting element is made from composite material or material with properties intermediate between aluminum and copper. It combines sufficient mechanical strength and elasticity to handle wire bonding forces with appropriate contact characteristics for semiconductor interfacing, achieving a balance that neither pure aluminum nor direct copper contact can provide.
3Reliability
If high compressive forces are applied during contacting to ensure good electrical connection, then electrical conductivity is improved, but crack formation and stress increase reducing service life
Solution Approach 1:
The contacting element serves as a stress-buffering intermediary that decouples the high compressive forces needed for good wire bond contact from the semiconductor element. It maintains adequate electrical connection without transmitting damaging force concentrations to the semiconductor, preventing crack formation while ensuring conductivity.
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 thermal spraying method and textured layer structure increase the service life of semiconductor arrangements by reducing crack formation and stress, while providing improved mechanical and thermal properties.
Implementation Method 1
at least one metallic contacting element (10) is produced by being sprayed onto the semiconductor element (4) by means of a thermal spraying method
Implementation Method 2
The textured layer distributes compressive forces and compensates for coefficient of thermal expansion mismatches, acting as a buffer layer to enhance the service life
Data Source
AI summary
A semiconductor arrangement includes a semiconductor element having a connection element, and a metallic contacting element connected flatly to the connection element of the semiconductor element by being sprayed onto the semiconductor element via a thermal spraying method involving atmospheric plasma spraying. The metallic contacting element incudes first and second particles which form a textured layer, with the first particles deformed in a planar-like manner and with the second particles being melted second particles, said first particles being at least five times larger than the second particles.