Copper Joining Paste Using Dihydroterpineol for Printability and Strength
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Solution Overview
Problem
Existing copper pastes for joining semiconductor elements face challenges in achieving both sufficient printing properties for automated printing and joining strength, particularly in mass production processes, due to issues with viscosity and dispersibility.
Innovation Solution
A copper paste containing copper particles and dihydroterpineol as the dispersion medium, with specific particle size and concentration ratios, enhances dispersibility and thixotropy, allowing for improved printing and joining properties without pressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If copper particle concentration is increased to ensure sufficient joining strength, then joining properties are improved, but viscosity increases and printing properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the dispersion medium by selecting dihydroterpineol with specific molecular structure and properties. This parameter change allows the paste to maintain low viscosity even at high copper particle concentrations (85-98 mass%), thereby improving both joining strength and printing properties simultaneously
Solution Approach 2:
Dihydroterpineol acts as an intermediary substance between copper particles and the printing process. Its specific chemical properties mediate the interaction between high particle concentration and viscosity, enabling the paste to flow easily during printing while maintaining structural integrity for strong joining
2Ease of operation
If copper particle concentration is decreased to improve printing properties, then printing properties are improved, but joining strength becomes insufficient
Solution Approach 1:
The patent modifies the dispersion medium parameters to dihydroterpineol, which has superior dispersibility and affinity for copper particles. This allows the system to achieve adequate viscosity control even at high particle concentrations, enabling both good printing properties and sufficient joining strength
3Ease of operation
If conventional dispersion media are used to reduce viscosity, then printing properties are improved, but dispersibility of copper particles deteriorates
Solution Approach 1:
Dihydroterpineol serves as a specialized intermediary dispersion medium that provides both low viscosity for printing and high dispersibility for copper particles. Its molecular structure enables it to interact effectively with copper particle surfaces while maintaining paste fluidity
Solution Approach 2:
The patent changes the dispersion medium from conventional options to dihydroterpineol with specific chemical parameters. This parameter change optimizes both viscosity and dispersibility simultaneously, resolving the trade-off between printing properties and particle dispersibility
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 copper paste enables efficient production of joined bodies with enhanced printing and joining properties, suitable for automated printers, while maintaining strong adhesion and reducing the risk of volume shrinkage and cracking.
Implementation Method 1
a copper paste for joining containing metal particles and a dispersion medium, in which the copper paste for joining contains copper particles as the metal particles, and the copper paste for joining contains dihydroterpineol as the dispersion medium
Implementation Method 2
since dihydroterpineol can increase thixotropy of a paste, both of fluidity during printing and the shape retaining force of the paste after printing are achieved in a high level
Implementation Method 3
a second step of sintering the copper paste for joining of the laminate
Data Source
AI summary
A copper paste for joining contains metal particles and a dispersion medium, in which the copper paste for joining contains copper particles as the metal particles, and the copper paste for joining contains dihydroterpineol as the dispersion medium. A method for manufacturing a joined body is a method for manufacturing a joined body which includes a first member, a second member, and a joining portion that joins the first member and the second member, the method including: a first step of printing the above-described copper paste for joining to at least one joining surface of the first member and the second member to prepare a laminate having a laminate structure in which the first member, the copper paste for joining, and the second member are laminated in this order; and a second step of sintering the copper paste for joining of the laminate.