HTCC Ceramic PCB

HTCC Ceramic PCB

HTCC is also known as high-temperature co-fired multilayer ceramics. The manufacturing process is very similar to LTCC. The main difference is that the ceramic powder of HTCC does not add glass material. Therefore, HTCC must be dried and hardened at a high temperature of 1300~1600℃ to form Green embryo, then drill the via hole, fill the hole and print the circuit with the screen printing technology. Because of the high co-firing temperature, the choice of metal conductor material is limited. The main material is high melting point but conductive Metals such as tungsten, molybdenum, manganese, etc., which are less durable, are finally stacked and sintered.


HTCC high-temperature co-fired ceramic materials are mainly ceramics composed of alumina, mullite and aluminum nitride. HTCC ceramic powder does not add glass materials. Due to the high firing temperature of the HTCC substrate, low-melting-point metal materials such as gold, silver, and copper cannot be used. The conductor paste is made of high-melting-point metal heating resistor paste such as tungsten, molybdenum, molybdenum, and manganese.


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HTCC Ceramic PCB material


HTCC materials are sintered in an environment higher than 1500°C. Due to the good thermal stability of HTCC materials, it is very suitable for applications in ultra-high temperature environments.

 

High-temperature co-fired ceramic materials are ceramics whose main components are alumina, mullite (the main body is Al2O3-SiO2) and aluminum nitride. The common HTCC green ceramic tapes are alumina ceramics, aluminum nitride ceramics and zirconia ceramics, etc. The thickness of green ceramic tapes prepared by tape casting method generally ranges from 50 μm to 700 μm.

 

Al2O3

During sintering, the ceramic particles phase-transform into a dense material, and the samples shrink by approximately 15% to 20%. Among them, in the field of ultra-high temperature, 99.99% alumina high-temperature co-fired ceramics are the most widely used. Some basic material characteristic parameters of HTCC alumina green ceramic tape are shown in the figure below.

Parameter

Value

Dielectric constant

9.5-9.9

Density(g/cm3)

3.8-3.95

Young's modulus(GPa)

340-380

Poisson's ratio

0.2-0.23

Bending strength(MPa)

450-650

Thermal conductivity(Wm-1K-1)

25-35

Thermal expansion coefficient(ppm℃-1)

6-8

Moh's hardness

9.0

Dielectric loss(25℃,1MHz)

0.0001

Volume resistivity(Ω.cm)

1×1014

Dielectric breakdown voltage(KV/mm)

>15

Sintering temperature

1500-1700

 

During the high-temperature sintering process, the green porcelain body often has a certain shrinkage ratio, and the shrinkage ratio is about 15%-20%. In order to make the sensor designed in this paper meet the design requirements and performance requirements, before sintering, it must be Calculate the size of the green porcelain blank according to the shrinkage ratio to prevent the final product from failing to meet the requirements.

Alumina ceramic technology is a relatively mature microelectronic packaging technology. It is sintered at 1500-1700°C by 92-96% alumina and 4-8% sintering aid. The wire material is tungsten and molybdenum. , molybdenum-manganese and other refractory metals.

The technology of the substrate is mature, the cost of the dielectric material is low, and the thermal conductivity and bending strength are high.

 

AI₂O₃-SiO₂

The dielectric constant of AI₂O₃-SiO₂ is 7.3-7.5, while the dielectric constant of Al₂O₃ (96%) is 9.4, which is higher than that of AI₂O₃-SiO₂, so the signal transmission delay time of AI₂O₃-SiO₂ can be about 17% shorter than that of alumina, and, The thermal expansion coefficient of AI₂O₃-SiO₂ is very close to that of silicon, so this substrate material has been developed rapidly. AI₂O₃-SiO₂ is mainly used in multilayer ceramic substrates, and its products have good performance indicators. However, the wiring conductors of this substrate can only be tungsten, nickel, molybdenum, etc., and the resistivity is relatively high and the thermal conductivity is lower than that of the Al₂O₃ substrate.

 

AlN

For AlN substrates, due to the high thermal conductivity of AlN, the coefficient of thermal expansion matches that of semiconductor materials such as Si, SiC and GaAs, and its dielectric constant and dielectric loss are better than Al2O3, and AlN is a relatively hard ceramic. Works well under ambient conditions.

Material

Melting point(°C)

Thermal conductivity(Wm-1K-1)

Relative permittivity

Dielectric breakdown voltage(KV/mm)

AI₂O₃

1860

29

9.7

10

AlN

2470

240

8.9

15

 

AlN substrate has more advantages than other high-temperature co-fired ceramic substrates, and has a good development prospect in the field of high-temperature co-fired (HTCC) ceramics. Mainly used in sensor packaging, surface mount packaging, MEMS packaging, optical communication packaging, LED packaging, etc.

 

 

HTCC Ceramic PCB manufacturing process

First, prefabricate alumina ceramic powder (90%~92% A1203) dispersion or slurry in liquid medium (solution or plasticized resin binder), and then cast the slurry into Flakes. The dried sheet is the green-ceramic stage and can be cut to size, punched through holes (for future interconnects through the dielectric layer) and formed into cavities. The desired conductive paths to be determined are printed onto the surface (usually using a tungsten powder paste), and then the vias are filled with metal. Within a precisely aligned jig, multiple such sheets are laminated together, and the entire structure is then sintered in a reducing atmosphere at 1600°C to form a single sintered body.

 

After the laminate structure is sintered, lead/pin bonding and metallization plating can be performed. For packages that require leads or pins, the exposed tungsten printed blocks that are prepared for soldering leads/pins must first be plated with nickel, made of Kovar (a F^Ni-Co alloy) or 42 alloy material The leads/pins are brazed with Ag-Cu eutectic alloy. After lead/pin soldering, all exposed metal surfaces are electroplated or electroless plated (usually nickel followed by gold) for bondability and environmental protection.

 

From powder preparation (grinding, mixing, casting), slicing, punching, filling, printing electrode, lamination, isostatic pressing, cutting, debinding, sintering, external motor reserve, external motor sintering, external motor Plating, testing such a process.

 

Tungsten-filled through-hole ceramic layers range in thickness from 0.002 to 0.025 inches (0.05 to 0.64 mm). Screen printed dielectric layer thickness is usually 0.001~0.003 inches (0. 025~0. 076mm).

 

Our ceramic packages are all manufactured using our own process and we have extensive in-house equipment capabilities for maximum efficiency. From prototypes to full production, Beton can support a wide range of production volumes.

 

 

Beton Ceramic PCB Process Development

Laser drilling:

• Laser fiber rotary cutting process

• Pore diameter range ± 10μm

• Taper <10μm

• Minimum pore size 50μm

• Accuracy ±3μm

Magnetron sputtering:

• Horizontal double-sided coating

• Strong binding force: >1KGf/mm²

• High uniformity >90%

Grinding and polishing:

• Semiconductor wafer grinding and polishing process

• Surface Ra<0.1μm, Rz<1μm

• TTV<±5μm

• Compatible with AuSn eutectic soldering requirements

Photolithography process:

• Minimum resolution 20μm

• Semiconductor grade clean room, Class 1,000

• CCD/LDI automatic exposure machine

• Alignment accuracy ≤20um.

 

HTCC ceramic PCB Advantage and Application

 

High-temperature co-fired ceramic (HTCC) pcbs are drilled, filled with metal paste and printed on each layer of green ceramic, and finally stacked together to form a substrate for multi-layer conductor interconnection. It has the advantages of high mechanical strength, high thermal conductivity, stable chemical properties and high wiring density.

 

Heater

HTCC ceramic substrate is a new type of high-efficiency environmental protection and energy-saving ceramic heating element. Compared with PTC ceramic heating element, it can save 20-30% of electric energy under the same heating effect. It can be used in the heating of small warm air heaters, hair dryers, dryers, electric heating splints, toilet ceramic heaters, water heaters, infrared physiotherapy instruments, intravenous fluid heaters, small special crystal device constant temperature tanks, industrial drying, etc. element.

 
Multilayer ceramic substrate

Because HTCC multilayer substrates have the characteristics of high mechanical strength, high thermal conductivity, low material cost, stable chemical properties, and high wiring density, HTCC substrates have been widely used in high-reliability microelectronic integrated circuits and high-power micro-assembly circuits. , Automotive high-power circuits and other product fields.

 

Ceramic shell

Ceramic shells are mainly used in the electronic packaging industry, such as high-power electronic tubes, electric vacuum tube switches, chip packaging, etc.

HTCC ceramic substrates are used for precision circuit interconnection and are very popular for highly integrated circuits. The main reason is that the high-temperature co-fired HTCC ceramic substrate is fired in a high-temperature environment above 1500°, with high thermal conductivity, good insulation, and stronger mechanical strength.

 

If you want to know about the HTCC ceramic pcb, please contact us. Our engineer can help to evaluate your ceramic pcb and put forward the EQ advice to ensure that the ceramic pcb are all be good quality. So any HTCC ceramic pcb demands, please contact us freely. We are very glad to help to manufacture for you.