Ceramic Substrates – Types, Advantages, Properties and Uses

November 20, 2024

Introduction

Ceramic Substrates are a base material typically used in power modules for thermal management, offering electrical insulation and mechanical support. Due to the ideal inherent combination of high thermal conductivity, high-voltage and current insulation properties, mechanical strength, and corrosion resistance, the performance and reliability of devices, such as power electronics and high-temp packaging ceramics, with ceramic substrates are significantly optimized.

Ceramic Substrate Advantages

When you choose ceramic substrates, they will repay you and bring many benefits, primarily including

※ Offering quick high-heat transfer and dissipation because of its high thermal conductivity

※ Owning low thermal expansivity with temperature fluctuations with mounted chips

※ Possessing friendly bonding capability with multifarious metals via specific media

※ Supplying excellent insulation breakdown, ideal for various high-voltage, high-current circumstances

※ Providing superior chemical stability and inertness, it will not react with most acids, alkalis, and salts in the air and never oxidize.

Types of Ceramic Substrates

Ceramic substrates are made from a variety of advanced ceramic materials. According to the categories of raw materials used in most practical applications, they can be mainly classified into the following types:

1. Alumina Al2O3 Ceramic Substrate

It is the most commonly used ceramic substrate because of its cost-effectiveness. It holds an above-80 % share in the ceramic substrate market.

2. Aluminum Nitride Aln Substrate

Aluminum Nitride Substrate is featured by its fabulous thermal conductivity up to 180W/m.k at room temperature.

3. Silicon Nitride Si3N4 Substrate

Silicon Nitride Substrate is known for its superb bending strength and high thermal shock resistance among ceramic substrates.

4. Zirconia ZrO2 Ceramic Substrate

Zirconia Ceramic substrate is characteristic of its super-high fracture toughness and distinctive thermal isolation properties.

5. Beryllia Oxide BeO Ceramic Substrate

It is a ceramic substrate that people both like and hate. Some love its ultra-high thermal conductivity, but others hate it because of its high toxicity during powder preparation.

Ceramic Material Properties Comparison

Different ceramic substrate materials exhibit unique properties to achieve designated needs and functional requirements in numerous industries, and you can discover some information below for deciding on a choice in your specific cases:

General	Properties	Unit	Material
General	Properties	Unit	Al2O3		AlN	Si3N4	ZrO2	BeO
Purity	--	%	≧96%	≧99.5%	≧99.6%	≧96%	≧96%	≧99.6%
Density	--	g/cm³	3.75	3.90	3.25	3.18	6.0	2.90
Thermal	Thermal Conductivity@ 25℃	W/m.k	20	30	180	80	3	310
	CTE @ 25℃ ~ 400℃	10^-6/K	7.2	7.4	4.4	3.2	7.8	7.5
	Specific Heat @ 25℃	J/(㎏･K)	750	780	720	700	460	840
Electrical	Volume resistivity	Ohm. cm	≧10¹⁴	≧10¹⁴	≧10¹⁴	≧10¹⁴	≧10¹⁴	≧4*10¹⁰
	Dielectric constant	1MHz	9.4	9.8	9	4	33	6~7
	Dielectric loss factor	10^-3	≦3	≦1	≦2	--	≦16	≦0.4
	Insulation breakdown @DC	KV/mm	≧15	≧15	≧15	≧100	≧10	≧10
Mechanical	Bending strength	MPa	＞350	＞500	＞400	＞800	＞800	＞310
	Modulus of elasticity	GPa	340	300	320	320	200	350
	Vickers hardness	GPa	14	16	11	15	11	9
	Fracture toughness	MPa.m^1/2	3.0	--	3.0	6.7~8	5.0	3.5~4.5
Others	Toxicity	--	None	None	None	None	None	Toxic

Uses of Ceramic Substrates

※ Alumina Ceramic Substrates

Due to the characteristics of high-purity alumina substrates, which have relatively low thermal conductivity and high thermal expansion coefficient, are primarily used in automotive electronics, semiconductor lighting, and electrical equipment.

※ Aluminum Nitride Substrates

Because aluminum nitride ceramic material has high thermal conductivity and thermal expansion coefficient, in addition to its high insulation strength and low dielectric constant, it is an ideal packaging substrate and heat dissipation material.

※ Silicon Nitride Substrates

Given the high mechanical strength, high thermal conductivity, and thermal shock resistance of silicon nitride (Si3N4) ceramics, Si3N4 substrates are widely used in high-power semiconductors, high-end equipment, new energy vehicles, and aircraft engines.

※ Zirconia Ceramic Substrates

Considering that zirconia (ZrO2) ceramics have excellent mechanical properties, thermal insulation, refractive index, and wide spectral transparency, they are widely used in industry, electronics, optics, and medicine.

※ Beryllia Ceramic Substrates

Beryllium oxide substrates have low density, extremely high thermal conductivity, and good comprehensive performance. However, BeO powder is highly toxic and expensive, so it is only used in a few fields, such as high-power, high-frequency semiconductor devices, avionics, and satellite communications.

Final Thoughts

In a word, the application of ceramic substrates has covered almost all high-end electronic power and even communications, computers, military, and aerospace fields. With the innovation and progress of technologies in various application fields, the global ceramic substrate market will grow substantially.

With continuous breakthroughs in ceramic substrate powder purification technology and the improvement of molding and Ceramic Metallization processes, ceramic substrates will develop towards thinner, higher performance, higher reliability, and higher integration.

Author:

Mr. Andy Chen

E-mail:

andy@jinghui0738.com

Phone/WhatsApp:

+86 13760126904