Copper Powder Surface Organic Coating Low-Temperature Sintering
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Solution Overview
Problem
Existing copper powders for low-temperature sintering face challenges such as oxidation, which inhibits sinterability, and the use of organic components that can lead to gas generation and defects in electronic components.
Innovation Solution
The development of copper powder with an average particle diameter of 250 nm or less, coated with a specific organic substance mixture that prevents oxide film formation and enhances low-temperature sinterability, achieved through a polyol method involving a polyol solvent and a chain organic substance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If copper powder is made into fine particles for low-temperature sintering, then sintering temperature is reduced, but oxidation resistance deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the organic substance on the copper powder surface. By specifying that the organic substance contains C, H, and O elements with specific atomic ratio ranges (C: 20-40 at%, H: 60-75 at%, O: 10-20 at%), the invention optimizes the balance between oxidation resistance and sinterability, resolving the contradiction between fine particle size and oxidation resistance
Solution Approach 2:
The invention creates a composite surface structure on copper powder by forming an organic substance layer containing specific elements (C, H, O in defined ratios). This composite structure combines the oxidation resistance of the organic layer with the sinterability of copper, allowing low-temperature sintering while preventing oxidation
2Reliability
If organic components are added to copper powder for oxidation resistance, then oxidation resistance is improved, but gas generation increases causing defects
Solution Approach 1:
The invention precisely controls the atomic ratios of elements in the organic substance (C: 20-40 at%, H: 60-75 at%, O: 10-20 at%) to optimize decomposition behavior. This parameter optimization ensures sufficient oxidation resistance while limiting excessive gas generation that would cause defects, resolving the contradiction between protection and harmful byproducts
Solution Approach 2:
The invention creates a localized organic substance layer on the copper powder surface with specific compositional characteristics. This localized treatment provides oxidation resistance exactly where needed (on the surface) while controlling the overall organic content to minimize gas generation during processing
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 powder exhibits excellent oxidation resistance and low-temperature sinterability, as evidenced by thermal shrinkage ratios and the absence of oxide films that could inhibit sintering, making it suitable for applications in electronic components.
Implementation Method 1
heating and reducing copper oxide powder (raw material) in a polyol solvent
Implementation Method 2
having a surface covered with an organic substance
Implementation Method 3
low-temperature sinterability, as evidenced by thermal shrinkage ratios
Data Source
AI summary
The copper powder has a surface covered with an organic substance and satisfies the following conditions: (1) in detection of the organic substance on the surface of the copper powder by GC-MS, detected is a predetermined organic substance described herein; (2) in detection of the organic substance on the surface of the copper powder by LC-MS, detected is a predetermined organic substance described herein; (3) in measurement of the thermal shrinkage ratio of a green compact of the copper powder, a temperature at which the thermal shrinkage ratio is 1% is 230° C. or lower; and (4) in measurement of the thermal shrinkage ratio of the green compact of the copper powder, a temperature difference between a temperature at which the thermal shrinkage ratio in an inert atmosphere is 3% and a temperature at which the thermal shrinkage ratio in a reducing atmosphere is 3% is smaller than 10° C.