What is LTCC ceramic PCB?

As is well-known that there are three technologies in total that can make multi-layer ceramic circuit boards, they are Thick Film Ceramic PCB, HTCC Ceramic PCB and the last one is LTCC Ceramic PCB. At present, ceramic multilayer PCBs enjoy their greatest implementation in high-speed, high-power circuit applications. These boards have been shown to reduce parasitic capacitance by up to 90% as compared to traditional board materials and show the greatest promise for future use in the aerospace, medical devices, industrial, and automotive industries.

What is LTCC Ceramic PCB?

LTCC ceramic board was developed from the HTCC technology in the early 1980s. With the rapid development of electronics, LTCC PCBs have gained significant popularity in recent years due to their unique advantages over traditional PCBs. They are highly reliable, and durable, and offer excellent electrical and mechanical properties, making them ideal for use in high-performance electronic applications.

Different from HTCC ceramic board, the sintering temperature of LTCC is around 950oC (900-1000oC). At this temperature, the ceramic substrate is easy to bond with the copper layer and forms a high-density circuit without interference in three-dimensional (3D) space. In some ways, it also can be made into a 3D subgrade board with passive components.

The LTCC PCB is made of ceramic substrate/glass material as the dielectric layer and applies high conductivity metal materials such as Au, Ag, alloys (for example Pd/Ag, Pt/Ag) as electrode layers, printing circuits in parallel way, and then sinter under 1000oC.

The Manufacturing Process of LTCC Ceramic PCBs

The manufacturing process of LTCC ceramic PCBs involves several steps, including the schematic diagram, layout design, substrate preparation, via holes drill, circuit print and co-fire. The following are the key steps involved in the manufacturing of LTCC ceramic PCBs: 

1. Layout design Create a layout of the circuit board and design the electrical connections between the components. 

2. Substrate preparation Make sure the ceramic substrate is in the precise thickness and cut into pieces in the required dimensions.

3. Via holes drill

Due to LTCC ceramics mostly being multilayer PCB, the via holes are important to electrically connect the layers. This step is to laser drill the via holes according to the drawing. Please be noted the drill tolerance during the process. And then fill vias with copper by silkscreen printing.

4. Circuit print

Printing conductive paste on the substrate to form the circuits. This is typically done using screen printing or inkjet printing techniques. (If needed and required, place the passive components on the circuit layers.) 

5. Sinter the Substrate

Sintering the substrate under a temperature of around 800°C to 1000°C. This results in the substrate fusing together, forming a solid and highly stable circuit board. 

6. Adding Components

Mounted components onto the LTCC ceramic circuit board, the same as FR4 PCB done, this process we named Surface Mount Technology (SMT). Or you can add active components by wire bonding if required. 

 7. Testing and Quality Control

Finally, the circuit board is tested and inspected to ensure that it meets the required specifications and quality standards. 

Where Can We Apply LTCC Ceramic PCB to? 

LTCC ceramic PCB is popular because it enables the creation of multilayer ceramic PCBs in a three-dimensional design, which facilitates the production of high-density circuits with narrow trace spacing/widths and reduces the size of the whole product. The LTCC ceramic PCB features excellent conductivity, low dielectric constant, and low dielectric loss, making them an ideal choice for radio-frequency, microwave, and millimeter wave devices. Moreover, LTCC ceramic technology has the potential to manufacture electronic components and integrate them with front-end modules, enabling the production of high-performance and reliable electronic products. 

We can apply it in a wide range of electronic applications, including: 

1. Automotive Electronics: LTCC PCBs are used in the manufacture of automotive electronic systems, including engine management systems, powertrain controls, and safety systems.

2. Aerospace and Defense: Due to their high reliability and resistance to extreme temperatures and harsh environments, make them suitable for this field.

3. Medical Electronics: LTCC PCBs are used in medical devices and equipment, including implantable devices, diagnostic equipment, and patient monitoring systems.

4. Telecommunications: LTCC PCBs are used in telecommunications equipment, including cell phones, wireless routers, and network switches.

5. Other files: LTCC is designed in small size, thin thickness and lightweight. For this reason, you can use it for some electronic component fabrication, facial cleanser for beauty, and so forth.

Why use LTCC Ceramic PCB and when to use it?

LTCC PCB offers numerous benefits for electronic industries due to their unique advantages over traditional PCBs. However, like any technology, LTCC ceramic PCBs also have some disadvantages. So understanding its pros and cons can help you to know how and when to use it for better performance. 

1. Advantages of LTCC Ceramic PCBs:

High Reliability: LTCC ceramic PCBs have high reliability due to their excellent thermal stability, mechanical strength, and electrical insulation properties. They are highly resistant to extreme temperatures, humidity, and chemical exposure, making them ideal for use in harsh environments.

Multilayer Design: LTCC ceramic PCBs can be designed with multiple layers, which allows for more complex circuits to be integrated into a single board. This results in a reduction in the size of the final product and an increase in its functionality.

High-Frequency Operation: LTCC ceramic PCBs can operate at high frequencies, making them ideal for use in high-speed applications such as telecommunications and RF/microwave systems.

Excellent RF Properties: LTCC ceramic PCBs have low loss and low dispersion characteristics, making them ideal for use in RF/microwave applications.

Customizable: LTCC ceramic PCBs can be customized to meet specific requirements, such as size, shape, and electrical properties. This makes them highly versatile and suitable for a wide range of applications.

2. Disadvantages of LTCC Ceramic PCBs:

High Cost: LTCC ceramic PCBs are more expensive than traditional PCBs due to their complex manufacturing process and specialized materials.

Limited Availability: LTCC ceramic PCB supply is not widely available, and only a limited number of manufacturers specialize in their production.

Limited Board Thickness: LTCC ceramic PCBs have a limited thickness, typically less than 1mm. This can be a disadvantage in applications where a thicker board is required for mechanical stability.

High Processing Temperature: The manufacturing process of LTCC ceramic PCBs involves firing the substrate at high temperatures, typically around 800°C to 1000°C. This can be a disadvantage in applications where heat-sensitive components are being used.

Each type of ceramic PCB has its own unique advantages and disadvantages, and the choice of PCB type will depend on the specific requirements of the application. LTCC ceramic PCBs are mainstream for passive integration circuits and also popular for high-frequency/high-speed applications. 

The Key Physical Properties Comparison Between Three Types of Ceramic PCBs:

1. Thermal Properties

LTCC PCBs typically have a coefficient of thermal expansion (CTE) in the range of 5-8 ppm/°C, while HTCC PCBs have a CTE of around 6-7 ppm/°C. Thick film ceramic PCBs have a CTE that varies depending on the specific ceramic material used, but it is generally higher than LTCC and HTCC PCBs. LTCC and HTCC PCBs are both known for their excellent thermal conductivity and high-temperature stability.

2. Mechanical Properties

HTCC PCBs are known for their high mechanical strength, while LTCC PCBs have good flexural strength and are resistant to mechanical stress. Thick film ceramic PCBs typically have lower mechanical strength than LTCC and HTCC PCBs, but they can still withstand moderate levels of mechanical stress.

3. Electrical Properties

All three types of ceramic PCBs have excellent electrical insulation properties due to their ceramic composition. LTCC and HTCC PCBs have a low dielectric loss and high dielectric strength, making them suitable for high-frequency and high-voltage applications. Thick-film ceramic PCBs have a lower dielectric strength and are typically used in lower-voltage applications.

4. Chemical Properties

LTCC and HTCC PCBs are highly resistant to chemical corrosion and can withstand exposure to a wide range of chemicals. Thick-film ceramic PCBs may be less resistant to chemical corrosion depending on the specific ceramic material used.

 In summary, LTCC, HTCC, and thick film ceramic PCBs have different physical properties due to their different compositions. The choice of ceramic PCB type will depend on the specific requirements of the application. If you have doubts about LCTT ceramic PCB fabrication and assembly, welcome to contact us at any time.