Copper Bonding Paste Composition for Stable Viscosity
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Solution Overview
Problem
Existing bonding pastes containing copper particles face challenges in maintaining stable viscosity over time, leading to difficulties in appropriate application and effective bonding of members.
Innovation Solution
A bonding paste comprising copper particles, a terpineol solvent, and a phosphate ester additive, with specific molecular weight and content ratios, ensuring a viscosity change rate of 20% or less between one day and thirty days after production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copper paste is used as a bonding material, then bonding between members can be achieved, but the viscosity of the paste changes over time making appropriate application difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the paste by introducing a phosphate ester additive with specific molecular weight characteristics. This additive modifies the paste's rheological properties to maintain stable viscosity over time, resolving the contradiction between achieving reliable bonding and maintaining compositional stability during storage and application
Solution Approach 2:
The phosphate ester acts as an intermediary substance between the copper particles and the solvent in the paste. It mediates the interaction to prevent excessive viscosity changes over time while still allowing the copper particles to function effectively for bonding, thus maintaining both bonding reliability and viscosity stability
Data Source
Figure 1~2
Figure 3
AI summary
A bonding paste is appropriately applied to a member. A bonding paste 10 includes a bonding paste containing copper particles 12, a solvent 14, and an additive 16, in which a viscosity change rate between one day after and thirty days after the bonding paste 10 is produced is 20% or less.