Sintered Bond Layer for High-Temperature Microelectronic Mounting

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Solution Overview

Problem

The maximum temperature rating of solder joints in packaged microelectronic components limits the effective power dissipation and output power in high-power applications due to solder creep and fatigue at temperatures above 110°C.

Innovation Solution

A method involving a metal particle-containing material with silver, gold, or platinum particles, applied as a film or tape, is used to create a sintered bond layer between the microelectronic component and a secondary structure, allowing sintering at temperatures above 130°C but below 300°C, thereby increasing the operational temperature and power dissipation capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If solder is used to mount packaged microelectronic components to secondary structures, then the mounting process is simple and well-established, but the maximum temperature rating is limited to approximately 110°C due to solder creep and fatigue

Engineering Contradiction:
Improvemaximum temperature ratingVSAvoidsolder joint reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention changes the material parameter from traditional solder to metal particle-containing material that can be sintered at higher temperatures (greater than 130°C and less than 300°C). This parameter change allows the bond layer to withstand higher operating temperatures while maintaining joint integrity, directly resolving the temperature limitation of solder joints.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material consisting of metal particles (silver, gold, copper, or platinum) combined with organic material (epoxy). This composite structure provides both the high-temperature capability of metal particles and the bonding properties of organic materials, enabling reliable mounting at temperatures above solder's limit.

Inventive Principle:
Principle #40Composite materials

2Power

If solder joints are used in high power applications, then the assembly process is straightforward, but the effective power dissipation and output power are limited due to temperature constraints

Engineering Contradiction:
Improvepower dissipation capacityVSAvoidoperational temperature limit
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

By changing the material composition from solder to sinterable metal particles with organic binder, the invention enables operation at higher temperatures (up to 300°C). This parameter change directly increases the power dissipation capacity since higher operating temperatures allow for greater power handling in microelectronic components.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If traditional solder mounting is used, then the process is well-established and simple, but the effective power dissipation is limited at temperatures above 110°C

Engineering Contradiction:
Improvemounting process simplicityVSAvoideffective power dissipation
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The invention modifies the material parameters to use metal particles with organic binder that can be applied in flowable wet state and sintered at elevated temperatures. This maintains ease of manufacture through simple application methods while enabling higher power dissipation capabilities through the sintering process that creates strong bonds at temperatures above solder's limit.

Inventive Principle:
Principle #35Parameter changes

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 raises the allowable power dissipation and output power of packaged microelectronic components by forming a durable sintered bond layer that exceeds the limitations of traditional solder joints, enabling the use of high-power devices like LDMOS and GaN transistor devices in higher temperature environments.

Implementation Method 1

sintering the metal particle-containing material at a maximum process temperature greater than 130 degrees Celsius (°C) and less than 300°C to produce a sintered bond layer joining the packaged microelectronic component to the secondary structure

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3404709B1Packaged microelectronic component mounting using sinter attachment
Publication Date: 2022.08.31 NXP USA INC
  • EP3404709B1 patent drawingFigure 1~2
  • EP3404709B1 patent drawingFigure 3
  • EP3404709B1 patent drawingFigure 4

AI summary

A packaged microelectronic component includes a substrate and a semiconductor die coupled to a top surface of the substrate. A method of attaching the packaged microelectronic component to a secondary structure entails applying a metal particle-containing material to at least one of a bottom surface of the substrate and a mounting surface of the secondary structure. The packaged microelectronic component and the secondary structure are arranged in a stacked relationship with the metal particle-containing material disposed between the bottom surface and the mounting surface. A low temperature sintering process is performed at a maximum process temperature less than a melt point of the metal particles to transform the metal particle-containing material into a sintered bond layer joining the packaged microelectronic component and the secondary structure. In an embodiment, the substrate may be a heat sink for the packaged microelectronic component and the secondary structure may be a printed circuit board.