Si3N4 Ceramic Substrate Void Reduction via Binder Solution
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Solution Overview
Problem
The conventional production process for ceramic substrates often results in voids due to inadequate homogenization of organic binders, which can degrade the mechanical strength and electrical properties of the product.
Innovation Solution
A process involving the use of hydroxypropylmethyl cellulose as an organic binder, with specific methoxy and hydroxypropoxy group content, and a twin screw extruder for kneading, followed by sintering, to produce a ceramic sheet with reduced voids and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional extrusion molding with organic binder powder is used, then production efficiency is improved, but voids appear in the sintered body due to binder segregation
Solution Approach 1:
The patent changes the physical state of the binder from powder to solution form. The organic binder is dissolved in a solvent to create a liquid binder solution, which is then applied to the ceramic powder mixture. This parameter change prevents binder segregation during extrusion while maintaining production efficiency, as the liquid binder distributes more uniformly throughout the green body compared to powder binders.
Solution Approach 2:
The patent introduces a solvent as an intermediary medium to carry the organic binder. The binder solution acts as a mediator that facilitates uniform distribution of the binder throughout the ceramic powder mixture during the extrusion process, preventing the segregation issue that occurs with direct powder blending while maintaining manufacturing efficiency.
2Loss of time
If insufficient kneading is performed, then processing time is reduced, but voids appear inside the sintered body
Solution Approach 1:
The patent changes the binder from powder to solution form, which fundamentally alters the kneading process characteristics. The liquid binder solution provides better plasticity and cohesion to the green body, allowing for more effective void elimination during extrusion with reduced kneading time while maintaining or improving mechanical strength after sintering.
Solution Approach 2:
The patent partially replaces mechanical mixing with a chemical/physical solution approach. By using a liquid binder solution instead of mechanical powder blending, the system achieves more uniform binder distribution with less mechanical energy input and shorter processing time, while the solution chemistry ensures proper adhesion and void elimination.
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 process effectively reduces voids in ceramic substrates, enhancing their mechanical strength and electrical insulation, making them suitable for high-reliability ceramic circuit boards and modules with improved thermal conductivity.
Implementation Method 1
kneading the wet powder material by means of a twin screw extruder
Implementation Method 2
molding the powder material into a sheet by means of a single screw extruder equipped with a sheet die
Implementation Method 3
applying debindering and sintering treatments to the ceramic sheet
Data Source
Figure 1~2
Figure 3
AI summary
Provided are a process for producing a highly reliable ceramic sheet with stable quality by reducing voids, and a ceramic substrate using the sheet. A highly reliable ceramic sheet with stable quality is obtained by using hydroxypropylmethyl cellulose as an organic binder, kneading a powder material, preferably, with a twin screw extruder, and then forming a sheet by means of a single screw extruder equipped with a sheet die, and the sheet is suitably used for a ceramic substrate and a ceramic circuit board.