Multilayer Ceramic Substrate Via Alignment and Thermal Stress Control
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Solution Overview
Problem
The existing methods for preparing multilayer ceramic substrates face issues such as via hole misalignment, defects due to thermal expansion and contraction, and the inability to use various materials, leading to defects like cracks, delamination, and conductivity issues, which result in high production costs and low yields, especially in the context of semiconductor integrated circuit testing.
Innovation Solution
A method involving the formation of ceramic thin films through controlled firing and heat treatment, where via holes are filled with conductive paste, and inner electrodes are printed on each film, allowing for precise alignment and lamination, with the use of a bonding agent to connect layers, enabling the use of different materials and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ceramic green sheets are laminated and fired simultaneously, then production efficiency is improved, but via hole misalignment and thermal stress defects occur
Solution Approach 1:
The patent divides the simultaneous firing process into separate stages: first forming via holes in individual green sheets before lamination, then firing layers sequentially. This segmentation prevents misalignment by establishing via hole positions before thermal expansion and contraction occur during firing, while still achieving efficient multi-layer production through the staged process.
2Device complexity
If all green sheets are fired at identical temperature, then process simplicity is maintained, but material versatility is limited
Solution Approach 1:
The patent implements dynamic firing control where different ceramic green sheets are fired at different temperatures according to their specific material requirements. The firing process is adjusted layer-by-layer, allowing each material type to be processed at its optimal temperature, thereby enabling versatile multi-material substrates without excessive process complexity.
3Reliability
If conductive paste is printed between green sheet layers, then inner electrodes are formed, but gaps and surface evenness defects occur
Solution Approach 1:
The patent applies preliminary compression to the ceramic green sheets before lamination to pre-form the surface topology. This preliminary action creates recesses where conductive paste will be placed, ensuring that when layers are stacked, the paste sits in designated areas without creating gaps or height differences, thereby maintaining both electrical conductivity and surface evenness.
4Reliability
If defects are detected after laminate firing, then complete quality assurance is achieved, but production waste increases
Solution Approach 1:
The patent implements preliminary defect detection and repair processes before final lamination and firing. Conductive paste is applied to via holes and tested for conductivity prior to stacking layers. Any defects are identified and corrected at this early stage, allowing defective individual sheets to be replaced without scrapping entire laminates, thereby reducing production waste while maintaining quality assurance.
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 approach prevents via hole misalignment, allows for defect detection and repair before completion, and enables the use of various materials, resulting in improved substrate evenness, durability, and reduced production costs, enhancing the yield and reliability of multilayer ceramic substrates.
Implementation Method 1
In the process of being fired and cooled, the laminate goes through thermal expansion and thermal contraction
Implementation Method 2
In the process of being fired and cooled, the laminate goes through thermal expansion and thermal contraction
Implementation Method 3
filling the via hall of each of the plurality of ceramic thin films with conductive paste, and heat treating the via hall filled with the conductive paste
Data Source
AI summary
The present disclosure relates to a multilayer ceramic substrate preparation method. The multilayer ceramic substrate preparation method according to the present disclosure includes firing a plurality of ceramic green sheets, to create a plurality of ceramic thin films; forming a via hall in each of the plurality of ceramic thin films; filling the via hall of the plurality of ceramic thin films with conductive paste, and heat treating the via hall filled with the conductive paste, to form a via electrode; printing a pattern on a cross section of each of the plurality of ceramic thin films, and heat treating the printed pattern, to form an inner electrode; applying a bonding agent on the cross section of each of the ceramic thin films excluding an uppermost ceramic thin film of the plurality of ceramic thin films; aligning and laminating each of the plurality of ceramic thin films such that each of the plurality of ceramic thin films is electrically connected through the via electrode and the inner electrode; and firing or heat treating the laminated plurality of ceramic thin films.