Silver Nanoparticle Conductive Features Using Titanium Precursor Sintering
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Solution Overview
Problem
Silver nanoparticle features degrade during high-temperature sintering, leading to low electrical conductivity due to the presence of polyvinylpyrrolidone (PVP) as a dispersant, which causes aggregation and loss of adhesion to the substrate.
Innovation Solution
A composition comprising silver nanoparticles, a titanium precursor compound, and non-aqueous polar protic solvents is used, with a concentration of titanium precursor in the range of 2 vol % to 13 vol %, and sintering at temperatures between 300° C. to 500° C. for 5 minutes to 90 minutes to form a contiguous conductive feature, while maintaining low aggregated particle density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature sintering (300°C or greater) is used to remove PVP from silver nanoparticle surfaces, then electrical conductivity is improved, but the conductive feature degrades with aggregation and loss of adhesion
Solution Approach 1:
The patent applies preliminary action by performing a pre-sintering treatment at a lower temperature (100°C to 300°C) for a shorter duration (5 minutes to 60 minutes) before the main high-temperature sintering process. This preliminary step removes a portion of the PVP dispersant and pre-heats the substrate, enabling the subsequent high-temperature sintering to proceed more effectively while reducing the risk of feature degradation and aggregation.
2Reliability
If high-temperature sintering is applied to remove dispersant, then electrical conductivity increases, but adhesion to substrate is lost
Solution Approach 1:
The pre-sintering treatment at 100°C to 300°C for 5 minutes to 60 minutes serves as a preliminary action that partially removes PVP and activates the substrate surface before high-temperature sintering. This prepares the substrate for better adhesion while setting the stage for effective conductivity enhancement in the subsequent high-temperature step.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the temperature range (100°C to 300°C) and time duration (5 minutes to 60 minutes) of the pre-sintering process. These specific parameter selections optimize the balance between PVP removal, adhesion preservation, and preparation for high-temperature sintering, preventing both aggregation and adhesion loss.
3Reliability
If extended sintering time is used to ensure complete PVP removal, then conductivity improves, but feature degradation increases
Solution Approach 1:
The pre-sintering treatment at lower temperature for 5 minutes to 60 minutes acts as a preliminary action that removes a significant portion of PVP before the main sintering process. This reduces the total sintering time required while ensuring adequate dispersant removal, thereby preventing feature degradation and maintaining manufacturing precision.
Solution Approach 2:
The patent implements continuity of useful action by dividing the sintering process into two continuous stages: pre-sintering (100°C to 300°C for 5 minutes to 60 minutes) followed by high-temperature sintering. This continuous two-stage approach ensures complete PVP removal through the combined effect of both stages while limiting exposure to high temperature, thus maintaining feature uniformity and preventing degradation.
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 results in high-quality, contiguous conductive features with improved electrical conductivity and adhesion to the substrate, reducing the number of aggregated particles and maintaining feature integrity during the sintering process.
Implementation Method 1
a titanium precursor compound... sintering the precursor feature at a temperature in a range of 300° C. to 500° C. for a time period of 5 minutes to 90 minutes to form a contiguous conductive feature
Implementation Method 2
a titanium precursor compound... sintering the precursor feature at a temperature in a range of 300° C. to 500° C. for a time period of 5 minutes to 90 minutes to form a contiguous conductive feature
Implementation Method 3
sintering the precursor feature at a temperature in a range of 300° C. to 500° C. for a time period of 5 minutes to 90 minutes
Implementation Method 4
The use of PVP as a dispersant affects the electrical conductivity of silver nanoparticles because the PVP present on the silver nanoparticle surfaces must be removed to obtain the best electrical conductivity. In order to effectively remove the PVP from the silver nanoparticle surfaces, a sintering process at a temperature of 300° C. or greater is desired
Data Source
AI summary
A composition for forming a contiguous conductive feature on a substrate includes silver nanoparticles, a titanium precursor compound, a first non-aqueous polar protic solvent, and a second non-aqueous polar protic solvent. The concentration of the titanium precursor compound in the composition is in a range of 2 vol % to 13 vol %. A method of forming a contiguous conductive feature on a substrate includes dispensing the composition on the substrate to form a contiguous precursor feature and sintering the contiguous precursor feature at a sintering temperature in a range of 300° C. to 500° C. to form the contiguous conductive feature. Example titanium precursor compounds are: titanium(IV) butoxide, titanium(IV) isopropoxide, titanium(IV) chloride, tetrakis(diethylamido)titanium(IV), and dimethyltitanocene.