Photosensitive Conductive Paste Shrinkage Control
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Solution Overview
Problem
The existing photosensitive conductive pastes used in forming multilayer electronic components face issues with delamination and electrode disconnection due to firing shrinkage differences between conductor and insulation layers, and increased metallic particle content affects light transmittance and patterning precision.
Innovation Solution
A photosensitive conductive paste comprising 70.3 to 85.6 mass % conductive powder, a photosensitive resin composition, and a glass frit with a softening point above the sintering temperature of the conductive powder, along with a refractive index difference of 0.10 or less between the resin composition and glass frit, to reduce firing shrinkage and enhance patterning resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of metallic particles (Ag particles) is increased to reduce firing shrinkage, then the firing shrinkage is reduced and delamination is prevented, but light transmittance is reduced and patterning precision deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the glass frit, specifically setting the SiO2 content to 70-80 mass%, B2O3 content to 15-20 mass%, and adding Al2O3 content of 10-20 mass%. These parameter changes optimize the refractive index and softening point of the glass frit to achieve both reduced firing shrinkage and maintained light transmittance for precise patterning
Solution Approach 2:
The patent creates a composite material system by combining metallic particles (Ag, Cu, or their alloys) with a specifically formulated glass frit composition. The glass frit acts as a matrix that binds the metallic particles while its optimized composition ensures compatible thermal expansion and appropriate refractive index, resolving the contradiction between shrinkage reduction and light transmittance
2Manufacturing precision
If the glass frit composition is optimized for low refractive index to maintain light transmittance, then patterning precision is improved, but firing shrinkage reduction capability deteriorates
Solution Approach 1:
The patent optimizes the softening point of the glass frit by adjusting the ratio of B2O3 (15-20 mass%) to SiO2 (70-80 mass%) and adding Al2O3 (10-20 mass%). This parameter optimization achieves a balance where the glass frit maintains appropriate refractive index for light transmittance while having sufficient softening point to effectively reduce firing shrinkage of the conductor layer
Solution Approach 2:
The patent applies the concept of local quality by ensuring the glass frit has different functional properties in different aspects: low enough refractive index for good light transmittance and patterning precision, but high enough softening point and appropriate composition for effective firing shrinkage reduction. The localized optimization of these properties within the glass frit composition resolves the contradiction
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
This solution effectively reduces delamination and electrode disconnection, maintains high resolution during photolithography, and produces reliable multilayer electronic components with minimal structural defects.
Implementation Method 1
a photosensitive resin composition containing an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent
Implementation Method 2
a glass frit, wherein: the mass ratio of the glass frit to the conductive powder is 0.020 to 0.054; and the glass frit has a softening point that is equal to or above a temperature at which sintering of the conductive powder starts
Data Source
AI summary
A photosensitive conductive paste that contains (a) a conductive powder in an amount of 70.3 to 85.6 mass % with respect to the total amount of the photosensitive conductive paste; (b) a photosensitive resin composition containing an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent; and (c) a glass frit. The mass ratio of the glass frit to the conductive powder is 0.020 to 0.054, and the glass frit has a softening point that is equal to or above the temperature at which sintering of the conductive powder starts.