Ceramic Substrate Package with Zirconia for Thermal Stress Resistance
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Solution Overview
Problem
Conventional electronic component element housing packages face challenges in achieving both increased bending strength of the ceramic substrate and bond strength of the metal layers, while also maintaining a high thermal conductivity and reflection rate for visible light.
Innovation Solution
A ceramic substrate composed of alumina, partially stabilized zirconia, and a sintering agent, with a metal layer containing tungsten, molybdenum, and a ceramic component, is simultaneously fired in a reducing atmosphere, achieving a bending strength of at least 550MPa and bond strength of 25MPa, and a high reflection rate through a tetragonal phase zirconia content and appropriate sintering agent content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the ceramic substrate is reduced, then the package size and profile are reduced, but the package becomes unable to withstand thermal stress during metal cover bonding
Solution Approach 1:
The patent uses a composite ceramic material consisting of alumina (91-94 wt%) combined with zirconia (3-10 wt%) and sintering agents (2-7 wt%). This composite structure provides both high strength to withstand thermal stress during bonding and enables reduced thickness while maintaining structural integrity. The zirconia addition specifically enhances toughness and thermal shock resistance, allowing the substrate to be thinner without compromising thermal stress resistance.
Solution Approach 2:
The patent modifies the ceramic composition parameters by adding zirconia and optimizing sintering agent content to achieve a material with enhanced mechanical properties. This parameter change allows the ceramic substrate to maintain high strength at reduced thickness, resolving the contradiction between miniaturization and thermal stress resistance.
2Strength
If the thickness of the ceramic substrate is increased, then the package can withstand thermal stress, but the package cannot be used as a small, low-profile package
Solution Approach 1:
The composite ceramic material with zirconia and optimized sintering agents provides superior strength-to-thickness ratio, enabling the substrate to withstand thermal stress at reduced thickness. This eliminates the need to increase thickness for strength, allowing simultaneous achievement of thermal stress resistance and compact package size.
Solution Approach 2:
By changing the material composition parameters (adding zirconia, optimizing sintering agents), the patent achieves enhanced mechanical strength that allows thickness reduction while maintaining thermal stress resistance, thus enabling low-profile package design.
3Ease of manufacture
If a sintering agent is added to lower the sintering temperature, then sintering can be performed without difficulty, but the bending strength of the ceramic substrate drops
Solution Approach 1:
The patent uses a composite formulation where zirconia (3-10 wt%) compensates for the strength reduction caused by sintering agents (2-7 wt%). The zirconia enhances toughness and bending strength, allowing the use of sintering agents to achieve lower sintering temperatures (1400-1600°C) while maintaining bending strength above 320 MPa.
Solution Approach 2:
The patent optimizes the balance between sintering agent content and zirconia content to achieve the desired sintering temperature reduction while maintaining adequate bending strength. The parameter optimization ensures that the strength loss from sintering agents is compensated by zirconia addition.
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 enhances the bending strength and bond strength of the ceramic substrate, maintains thermal conductivity comparable to alumina, and achieves a high reflection rate, enabling the creation of a smaller, lower-profile electronic component housing package suitable for thin and small-sized applications.
Implementation Method 1
the plurality of ceramic green sheets on which the metalized printed wiring is formed is layered by aligning and applying heat and pressure, then simultaneously firing the ceramic green sheets with high-melting point metal at a temperature of 1550-1600°C in a reducing atmosphere
Implementation Method 2
simultaneously firing the ceramic green sheets with high-melting point metal at a temperature of 1550-1600°C in a reducing atmosphere
Implementation Method 3
The electronic component element housing package is configured so that the sintering temperature of the sheets is lowered by adding the sintering agent to the sheets
Implementation Method 4
the Electronic component element housing package is configured so that the bond strength of the metalized layers of tungsten and molybdenum formed on the ceramic substrate can be increased by the glass component of the sintering agent
Implementation Method 5
a sintered body is formed containing 2.0-27.0% by weight of zirconium oxide on at least one of the ceramic substrate or the cover in order to increase the bend strength of ceramic substrates
Data Source
AI summary
To provide a package for storing electronic component elements, said package making it is possible to guarantee the bending strength of a ceramic substrate and the metalized joint strength of the metal layer. [Solution] A package (10) for storing electronic component elements, said package comprising a ceramic substrate (11) and a metal layer (12), wherein the package for storing electronic component elements is characterized in that: the ceramic substrate (11) contains 10 to 30 wt% of partially-stabilized zirconia by forming solid solution with yttria and 1.5 to 4.5 wt% of a sintering auxiliary agent formed from a combination of magnesia and at least one selected from silica, calcia, and manganese oxide, with the balance being alumina; the metal layer (12) contains 70 to 94 wt% of tungsten, 3 to 20 wt% of molybdenum, and 3 to 20 wt% of a ceramic component; and at least 60% of zirconia crystals in the ceramic substrate (11) after co-firing is in tetragonal phase.