Conductive TLPS Compositions for Low-Temperature Electronic Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The electronics industry faces challenges in achieving low-temperature assembly processes for semiconductor packaging due to the limitations of current materials, including thermosetting adhesives and low-melting solder alloys, which lack electrical and thermal performance and reliability, and are prone to remelting during thermal cycling.
Innovation Solution
A transient liquid phase sintering (TLPS) composition comprising two types of metallic particles, where one type is liquid at assembly temperature and the other is not, reacting to form intermetallics with melting points above the assembly temperature, utilizing specific metallic elements and organic compounds to enhance thermal and electrical conductivity while mitigating the drawbacks of SnIn and SnBi alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low-melting solder alloy materials are used, then assembly temperature can be reduced, but the materials have potential to remelt in operation or thermal cycling
Solution Approach 1:
The invention changes the chemical composition parameters of the solder alloy by incorporating reactive elements (such as tin, zinc, aluminum) that form intermetallic compounds with the substrate metal. This transforms the material properties so that while the base alloy has low melting point for assembly, the formed intermetallic junction has high melting point for operational stability.
Solution Approach 2:
The invention creates a composite structure consisting of the base solder alloy matrix combined with intermetallic compound formations at the interface. This composite approach allows the bulk material to remain low-melting for assembly purposes while the interfacial intermetallic layer provides high-temperature stability during operation.
2Temperature
If thermosetting adhesives with conductive fillers are used, then assembly temperature can be reduced, but electrical and thermal performance and reliability are insufficient
Solution Approach 1:
The invention changes the material state from solid adhesive with filler particles to a metallurgical bond formed through controlled reaction. By adjusting the chemical composition to include reactive metal elements, the material transitions from a polymeric adhesive system to a metal-based joining system that achieves both low processing temperature and superior electrical/thermal performance.
Solution Approach 2:
The invention replaces the mechanical adhesion mechanism of thermosetting adhesives with a metallurgical bonding mechanism. Instead of relying on polymer matrix adhesion and conductive filler pathways, the system uses intermetallic compound formation to create direct metallic bonds that inherently provide superior electrical and thermal conductivity.
3Temperature
If reactive elements are added to reduce melting temperature, then assembly temperature decreases, but the reactive elements are consumed during processing
Solution Approach 1:
The invention incorporates excess reactive elements in the initial alloy composition that are pre-positioned to react with the substrate metal during the assembly process. This preliminary inclusion ensures that sufficient reactive material is available to form the desired intermetallic layer while maintaining the low-melting characteristics of the base alloy.
Solution Approach 2:
The invention optimizes the compositional parameters of the solder alloy by carefully balancing the concentration of reactive elements. This parameter adjustment ensures that enough reactive material is present to form stable intermetallic junctions during assembly, while the overall composition maintains the desired low melting temperature for the assembly process.
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 provides compositions that are tolerant to thermo-mechanical stress, maintain thermal stability, and ensure robust, reliable electrical and thermal connections at temperatures below 140°C, overcoming the limitations of prior TLPS compositions by optimizing the proportion and reactivity of metallic particles.
Implementation Method 1
The first Type of particle becomes liquid at, or near, the assembly process temperature
Implementation Method 2
the reactive element(s) in the first particle Type interdiffuse and react rapidly with the reactive elements of the second particle Type
Implementation Method 3
react rapidly with the reactive elements of the second particle Type, thus resulting in consumption of the reactive elements in the first particle Type due to the formation of new reaction products
Implementation Method 4
transient liquid phase sintering (TLPS) is a technology that could be employed to resolve these problems
Data Source
AI summary
To provide a composition for electromagnetic wave shield capable of forming a sintered compact for electromagnetic wave shield excellent in electromagnetic wave shield effect. SOLUTION: A composition for electromagnetic wave shield includes: a metal particle A, a metal particle B with a lower fusion point than the metal particle A; a metal particle C which includes a metal composition contained in the metal particle B and is an alloy particle with a lower fusion point than the metal particle B; and resin. Between the metal particle A, the metal particle B and the metal particle C, transient liquid phase sintering is possible.