Customized ceramic circuit boards require understanding of the characteristics and processes of ceramic substrates

Ceramic substrates are widely used in LED, semiconductor, electric power, communication products, transportation rail and other fields, mainly based on the comprehensive advantages of ceramic substrates and process selection. Today, the editor will explain the characteristics of ceramic substrates and process summary analysis.

 

Ceramic substrates are widely used in LED, semiconductor, electric power, communication products, transportation rail and other fields, mainly based on the comprehensive advantages of ceramic substrates and process selection. Today, the editor will explain the characteristics of ceramic substrates and process summary analysis.

 

What is a ceramic substrate

 

Ceramic substrates are based on electronic ceramics, and form a sheet material that supports the components outside the membrane circuit element.

 

Classification of ceramic substrates:

 

 

Comparison of heat dissipation materials-plastic and ceramic materials

 

 

Comparison of ceramic materials - alumina and aluminum nitride

 

 

Classification by manufacturing process - types of ceramic substrates

 

LTCC low temperature co-fired ceramic multilayer ceramic substrate;

DBC direct copper-plated ceramic substrate;

DPC direct copper-plated ceramic substrate

 

1. Ceramic substrate type - HTCC

HTCC is also known as low temperature co-fired multilayer ceramics. The production process is very similar to LTCC ceramics. The main core difference is that the ceramic powder of HTCC does not contain glass material. Therefore, HTCC must be dried and hardened in a high temperature environment of 1300°~1600° to form a green embryo. Then, the via holes are drilled and the holes are filled and the circuits are made by screen printing technology. Due to the high co-firing temperature, the choice of metal conductor materials is limited. The main conductor materials are tungsten, molybdenum, manganese and other metals with high melting points but poor conductivity. Finally, they are sintered in layers.

 

 

 

2. Ceramic substrate type - LTCC LTCC is also known as low temperature co-fired multilayer ceramic substrate. This technology requires inorganic alumina powder and about 30%~50% glass materials, plus organic adhesives, to be mixed evenly to form a muddy slurry. Then, a scraper is used to scrape the slurry into sheets, and then a drying process is performed to form thin green embryos. Then, through holes are drilled according to the design of each layer to transmit the signals of each layer. The internal circuits of LTCC use screen printing technology to fill holes and print circuits on the green embryo. The internal and external electrodes can be made of silver, copper, gold and other metals. Finally, the layers are stacked and placed in a 850°~900° sintering furnace for sintering.

 

 

3. Ceramic substrate type - DBC

Direct copper clad technology DBC is to use copper oxygen-containing eutectic liquid to directly bond copper to ceramic. Its basic principle is

Before or during the bonding process, an appropriate amount of oxygen is introduced between copper and ceramic. In the range of 1065℃~1083℃, copper and oxygen form Cu-O eutectic liquid. DBC technology uses this eutectic liquid to react chemically with the surface of the ceramic substrate to form CuAIO2 or CuAI2O4 phase, and on the other hand, it wets the copper foil to achieve the bonding of the ceramic substrate and the copper plate.

 

4. Ceramic substrate types-Characteristics of direct copper DBC technology

 

 

5. Ceramic Substrate Type - DPC

DPC is also called direct copper plating substrate. Taking the DPC substrate process as an example, the ceramic substrate is first pre-treated and cleaned, and the copper-metal composite layer is sputtered on the ceramic substrate using the thin film professional technology - vacuum coating. Then, the photoresist is repeatedly exposed, developed, etched, and stripped by yellow light microlithography to complete the circuit production. Finally, the thickness of the circuit is increased by electroplating and chemical plating deposition. After the photoresist is removed, the metallized circuit production is completed.

 

 

 

Characteristics of ceramic substrates

 

In the comparison of the characteristics of ceramic heat dissipation substrates, the thermal conductivity, process temperature, circuit manufacturing method, and line width of the heat dissipation substrate are mainly selected.

In-depth analysis of line width and diameter:

 

   

1. Ceramic substrate characteristics-thermal conductivity

 

 

 

2. Ceramic substrate characteristics-operating environment temperature

 

 

3. Ceramic substrate characteristics - process capabilities

 

 

4. Ceramic substrate characteristics - differences in thin film and thick film processes

 

 

5. Ceramic substrate characteristics - development etching, laser engraving

 

 

Application of ceramic substrate