Conductive Copper Paste with Fatty Acid and Triethanolamine
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Solution Overview
Problem
Conductive copper pastes face issues with increased specific resistance under high-temperature and short-time curing conditions, and variability in specific resistance depending on copper powder content, limiting their reliability in semiconductor devices.
Innovation Solution
A conductive copper paste composition comprising copper powder, a thermosetting resin, a liquid fatty acid, and triethanolamine, with specific ratios and types of components to achieve ambient atmosphere curing, long pot life, and low specific resistance, including oleic acid, linolic acid, and linolenic acid as fatty acids, and a resol-type phenol resin for improved conductivity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive copper paste is used with high copper powder content, then conductivity is improved, but specific resistance increases under high-temperature and short-time curing conditions
Solution Approach 1:
The invention changes the chemical parameters of the paste composition by introducing a specific organic carboxylic acid (salicylic acid, benzoic acid, tartaric acid, citric acid, maleic acid, succinic acid, fumaric acid, or malonic acid) and controlling its content at 1-10 parts by mass per 100 parts by mass of copper powder. This chemical parameter change enables the paste to maintain stable specific resistance under high-temperature and short-time curing conditions while preserving good conductivity.
Solution Approach 2:
The invention creates a composite material system combining copper powder with specific organic carboxylic acids and thermosetting resins. This composite approach allows the organic carboxylic acid to act as a protective agent that prevents copper oxidation and maintains electrical conductivity, while the thermosetting resin provides structural stability during high-temperature curing, achieving both low specific resistance and reliability.
2Ease of manufacture
If copper is used as conductive filler instead of silver, then cost is reduced and anti-migration property is improved, but curing in ambient atmosphere becomes difficult
Solution Approach 1:
The invention introduces organic carboxylic acid as an intermediary substance between copper powder and the ambient atmosphere. This intermediary forms a protective complex with copper, preventing direct oxidation of copper by atmospheric oxygen during the curing process. The organic carboxylic acid acts as a reducing agent and protective agent, enabling ambient atmosphere curing while maintaining copper's anti-migration property and electrical conductivity.
Solution Approach 2:
The invention changes the chemical environment parameters by adding organic carboxylic acid (1-10 parts by mass per 100 parts by mass of copper powder) and controlling the oxygen partial pressure and temperature during curing. This parameter control allows copper to be cured in ambient atmosphere without excessive oxidation, maintaining both ease of manufacture and reliability.
3Reliability
If high copper powder content is used to achieve low specific resistance, then conductivity is improved, but variability in specific resistance increases
Solution Approach 1:
The invention introduces a new controlling parameter: the content of organic carboxylic acid (1-10 parts by mass per 100 parts by mass of copper powder). This parameter change transforms the system from one where specific resistance is highly sensitive to copper content variations to one where specific resistance is stabilized by the organic carboxylic acid's protective and complexing effects, reducing variability while maintaining low resistance values.
Solution Approach 2:
The invention creates a composite system where organic carboxylic acid and copper powder work synergistically. The organic carboxylic acid forms stable complexes with copper particles, ensuring uniform distribution and consistent electrical pathways. This composite approach reduces specific resistance variability caused by copper content fluctuations, improving reliability and manufacturing precision simultaneously.
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 conductive copper paste achieves low specific resistance (<1×10−4 Ω·cm) and long pot life, ensuring high reliability semiconductor devices with stable connection resistance between semiconductor elements and substrates, even under high-temperature and short-time curing conditions.
Implementation Method 1
combining a copper powder, fatty acid that is liquid at normal temperature with triethanolamine provides a conductive copper paste described below. The conductive copper paste is curable in an ambient atmosphere
Implementation Method 2
a conductive copper paste that can be sintered in an ambient atmosphere
Implementation Method 3
a thermosetting resin
Data Source
AI summary
The purpose of the present invention is to provide a conductive copper paste which is curable in an ambient atmosphere, has a long pot life, and, has a low specific resistance even under a high-temperature and short-time curing condition, wherein the specific resistance after curing does not greatly vary depending on a copper powder content. The conductive copper paste provided is characterized by containing (A) a copper powder, (B) a thermosetting resin, (C) a fatty acid that is liquid at normal temperature, and (D) triethanolamine. Preferably, component (B) is a resol-type phenol resin. More preferably, the content of component (B) is 10 to 20 parts by mass with respect to a total of 100 parts by mass of component (A) and component (B).