Fe-B-Cu-C Alloy Magnetic Particles for Low-Frequency Induction Sintering
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Solution Overview
Problem
Current methods for forming conductive films using magnetic heating elements face challenges such as weak bonding strength, high temperature requirements, and heat-induced damage to electronic devices, particularly due to the need for fine particles and high-frequency induction heating, which can affect other devices and hinder smooth heat generation at lower frequencies.
Innovation Solution
The development of magnetic heating element particles with specific compositions and crystal grain sizes, produced through a method involving alloy ingot formation, rapid solidification, heat treatment, and pulverization, allowing for the creation of a conductive paste that can be sintered using induction heating at lower frequencies, enabling low-temperature bonding and selective heating of the conductive film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If superparamagnetic particles with strong magnetic characteristics are used, then magnetic heating effect is enhanced, but heat generation becomes insufficient at low frequencies and requires high-frequency current (10 kHz to 60 MHz)
Solution Approach 1:
The patent changes the magnetic characteristics parameter by transitioning from superparamagnetic particles to particles with moderate magnetic characteristics and crystalline structure. This parameter change enables the material to generate sufficient heat at low frequencies (1 kHz to 100 kHz) while maintaining adequate heating effectiveness, thus resolving the frequency range adaptability issue.
Solution Approach 2:
The patent uses composite material strategy by combining magnetic heating element particles with specific crystalline structure and moderate magnetic characteristics alongside metal particles. This composite approach allows the system to achieve both low-frequency heat generation capability and sufficient bonding effectiveness without requiring high-frequency currents.
2Use of energy by moving object
If fine magnetic heating element particles (2 to 100 nm) are used to enhance heat generation, then magnetic heating effect is improved, but dispersibility deteriorates and requires coating with non-magnetic material
Solution Approach 1:
The patent changes the particle size parameter from nanoscale (2-100 nm) to microscale (1 µm to 100 µm) and alters the magnetic characteristics parameter by creating crystalline structure. This combination of parameter changes improves dispersibility without requiring non-magnetic coatings while maintaining sufficient heat generation capability through the crystalline magnetic structure.
3Strength
If high temperature sintering is used to ensure bonding strength, then bonding strength is improved, but heat-induced damage to electronic devices occurs
Solution Approach 1:
The patent replaces the conventional high-temperature sintering mechanism with an induction heating mechanism using magnetic heating element particles. This substitution allows bonding to occur at lower temperatures (800°C to 1000°C) by generating heat directly within the magnetic particles through electromagnetic induction, thereby reducing heat-induced damage to electronic devices while maintaining bonding strength.
Solution Approach 2:
The patent utilizes phase transition of the magnetic heating element particles under alternating magnetic field to generate heat efficiently at lower temperatures. The moderate magnetic characteristics and crystalline structure enable effective hysteresis heating and eddy current heating at low frequencies, allowing sintering to proceed at lower temperatures compared to conventional methods, thus protecting electronic devices from thermal damage.
4Strength
If pressurized bonding method is used to achieve high bonding strength, then bonding strength is improved, but deformation of device chip and module occurs due to applied pressure
Solution Approach 1:
The patent replaces the mechanical pressurized bonding system with an electromagnetic induction heating system. By using magnetic heating element particles that generate heat under alternating magnetic field, the bonding process achieves high bonding strength through thermal activation rather than mechanical pressure, thereby preventing deformation of device chips and modules while maintaining strong bonding.
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
This approach enables the formation of a conductive adhesive layer with strong bonding strength, reduces external heat application, and minimizes interference with other devices by allowing induction heating at lower frequencies, thus providing efficient and controlled heat generation for bonding.
Implementation Method 1
when induction heating is performed over the conductive film, the magnetic heating element is magnetized to generate heat
Implementation Method 2
the magnetic heating element particles may have a coercive force of 100 Oe or more... generates heat through induction heating
Implementation Method 3
heat-treating the amorphous alloy ribbon to a first temperature or higher to crystallize the same
Data Source
AI summary
The present invention provides a method for manufacturing a conductive film, comprising the steps of: applying, to a substrate, a conductive paste dispersed in an organic material and comprising metal particles and Fe—B—Cu—C alloy magnetic heating element particles; and selectively sintering the applied conductive paste by means of induction heating so as to form a conductive film, wherein the magnetic heating element particles are implemented with crystallized Fe—B—Cu—C alloy particles. Therefore, it is possible to selectively form a conductive adhesive layer by sintering through induction heating. In addition, it is possible to produce an adhesive capable of low-temperature bonding by forming a magnetic heating element having crystal grains with a large coercive force through heat treatment after formation of an alloy.