Transferring Sintered Conductors to Heat-Sensitive Substrates

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Solution Overview

Problem

Fabrication of electrical devices with heat sensitive components is challenging due to the risk of damage from high sintering temperatures, which can render components inoperable, and existing conductive inks have high electrical resistance.

Innovation Solution

A method involving sintering a conductive material on a substrate that can withstand high temperatures, followed by transferring the electrical conductor to a heat-sensitive substrate, using materials like silver, gold, or copper with capping agents, and electrodeposition to achieve low electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sintering is performed at high temperature to reduce electrical resistance, then electrical conductivity is improved, but heat sensitive substrates are damaged

Engineering Contradiction:
Improveelectrical conductivityVSAvoidthermal damage to substrate
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The process is segmented into two distinct stages: first, sintering the conductive material on a heat-resistant substrate at high temperature to achieve low electrical resistance; second, transferring the sintered conductor to the heat-sensitive substrate. This segmentation allows the thermal processing and substrate application to be decoupled, resolving the contradiction between achieving good conductivity and protecting heat-sensitive substrates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat-resistant substrate is introduced as an intermediary carrier that can withstand high sintering temperatures. The conductive material is first sintered on this intermediary substrate, then transferred to the final heat-sensitive substrate. The intermediary substrate acts as a temporary platform that enables high-temperature processing without exposing the heat-sensitive substrate to damaging temperatures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional conductive inks are used, then fabrication is simplified, but electrical resistance is high

Engineering Contradiction:
Improvefabrication simplicityVSAvoidelectrical resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The electrical resistance parameter of the conductive material is changed by performing sintering treatment at high temperature (e.g., 800-1200°C). This thermal processing transforms the conductive material from a high-resistance state to a low-resistance state, achieving bulk electrical resistance of 4 microOhms-cm or less while maintaining the simplicity of ink-based fabrication.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If heat sensitive substrates are used, then device integration is improved, but conductor fabrication becomes difficult

Engineering Contradiction:
Improvedevice integrationVSAvoidconductor fabrication
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The fabrication process is segmented so that the conductor formation (requiring high temperature) and substrate integration (requiring low temperature) occur at different stages. The conductor is first formed on a heat-resistant substrate, then transferred to the heat-sensitive substrate, enabling both good device integration and ease of conductor fabrication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive material is sintered in advance on a heat-resistant substrate before being transferred to the heat-sensitive substrate. This preliminary sintering action achieves the desired low electrical resistance without exposing the heat-sensitive substrate to high temperatures, making the overall fabrication process easier and more compatible with heat-sensitive materials.

Inventive Principle:
Principle #10Preliminary action

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 allows for the production of devices with low electrical resistance conductors on heat-sensitive substrates, minimizing damage and enabling the creation of devices like printed electronics and solar cell contacts with improved conductivity.

Implementation Method 1

sintering the conductive material at the sintering temperature to form an electrical conductor

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

electrodeposition to achieve low electrical resistance

Methodology Applied
Scientific EffectElectrodeposition: Electrodeposition

Data Source

PatentEP1975946B1Devices & methods for producing & using electrical conductors
Publication Date: 2013.07.31 ALPHA ASSEMBLY SOLUTIONS INC
  • EP1975946B1 patent drawingFigure 1~2
  • EP1975946B1 patent drawingFigure 3A~3C
  • EP1975946B1 patent drawingFigure 4A~4D

AI summary

A device including a heat sensitive substrate and an electrical conductor disposed thereon is provided. In certain examples, the heat sensitive substrate may be configured to degrade at or above a sintering temperature. In other examples, the electrical conductor may be processed, prior to disposal on the heat sensitive substrate, at the sintering temperature on a second substrate that can withstand the sintering temperature. Methods and kits are also disclosed.