Low Oxygen Copper Paste for Stable Semiconductor Bonding
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Solution Overview
Problem
Conductive copper pastes face high specific resistance issues that vary significantly with copper powder content, and are limited by the types of resins used, restricting their applicability in semiconductor devices.
Innovation Solution
A resin composition comprising a copper powder with low oxygen content, a thermosetting resin, a fatty acid, and an amine or amine compound, which maintains low specific resistance after curing regardless of the resin type or copper powder content, forming a conductive copper paste suitable for semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper powder is used as a conductive filler to reduce cost and improve conductivity, then the specific resistance becomes lower, but the specific resistance significantly changes after curing depending on copper powder content
Solution Approach 1:
The patent specifies precise parameter ranges for copper powder (particle size distribution, tap density, oxygen content) and resin composition ratios to maintain stable specific resistance after curing. By controlling the copper powder oxygen content at 0.3% or less and specifying the resin-to-copper powder ratio, the invention achieves consistent electrical properties regardless of curing conditions.
Solution Approach 2:
The invention creates a composite material system combining copper powder with specific resin components (epoxy resin, phenolic resin, or both) in controlled ratios. This composite approach ensures that the conductive properties remain stable after curing by balancing the conductive copper network with the insulating resin matrix, preventing significant resistance changes.
2Temperature
If conventional conductive adhesives are used to bond semiconductor elements, then bonding can be performed at lower temperature, but the specific resistance is higher than solder
Solution Approach 1:
The invention optimizes the copper powder characteristics (high tap density, specific particle size distribution, low oxygen content) and resin composition to achieve ultra-low specific resistance (1×10^-4 Ω·cm or less) in the cured state. This parameter optimization allows conventional adhesive bonding processes to achieve solder-level conductivity while maintaining the advantage of lower bonding temperatures.
3Reliability
If copper powder content is increased to reduce specific resistance, then conductivity improves, but the specific resistance significantly changes after curing
Solution Approach 1:
The patent specifies the resin-to-copper powder mass ratio within 95:5 to 5:95 and optimizes copper powder parameters (particle size, tap density, oxygen content) to achieve stable low resistance after curing. This controlled composition ensures that even with high copper content for conductivity, the specific resistance remains stable through the curing process.
Solution Approach 2:
The invention creates a balanced composite where copper powder provides conductivity and resin provides structural stability. By controlling the resin components (epoxy, phenolic, or both) and their ratio to copper powder, the composite maintains dimensional stability and electrical property stability after curing, preventing resistance drift.
4Ease of manufacture
If resin types are limited to maintain processability, then manufacturing is simplified, but applicable uses are limited
Solution Approach 1:
The patent develops a universal resin composition system that works with multiple resin types (epoxy resin, phenolic resin, or both in combination) while maintaining consistent performance. This multi-functional resin system allows the same copper powder formulation to be used across different applications and bonding requirements, expanding versatility without complicating manufacturing.
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 achieves a low specific resistance value of less than 1×10−4 Ω·cm, ensuring a reliable connection between semiconductor elements and substrates with stable performance.
Implementation Method 1
a resin composition including (A) a copper powder having an oxygen content of 0.3% by mass or less, (B) a thermosetting resin, (C) a fatty acid, and (D) an amine or an amine compound
Implementation Method 2
a conductive copper paste including the resin composition
Data Source
AI summary
An object of the present invention is to provide: a resin composition in which the specific resistance after curing is low regardless of the type of a thermosetting resin, and furthermore, the specific resistance after curing does not significantly change depending on the content of a copper powder; and a conductive copper paste including the resin composition. There are provided a resin composition including (A) a copper powder having an oxygen content of 0.3% by mass or less, (B) a thermosetting resin, (C) a fatty acid, and (D) an amine or an amine compound, as well as a conductive copper paste containing the resin composition. The (A) component has an average particle size of preferably 1 to 10 μm.