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HTCC Ceramic PCB

Name: HTCC Ceramic PCB
Material: 99.6% Al2O3
Layers: 4L
Thickness: 5.0mm
Working Temperature: -40-300℃
Substrate Thickness: 3um
Application: Signal Converter System

High Temperature Co-fired Ceramic (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. 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.

Co-fired ceramic packages are fabricated through four distinct processing stages that include material preparation, green processing, sintering, and post-fire processing. Material preparation consists of milling raw materials into a dielectric “green tape” as well as conductive inks.HTCC must be dried and hardened at a high temperature of 1300~1600℃ to form Green embryo, Green processing consists of punching cavities, via punch, via fill, screen printing and lamination. Once the green process is complete, the ceramic/metal composite is “co-fired” in a carefully controlled atmosphere. Post fire processing consists of additional printing, sawing, machining and brazing. Almost all packages are plated with Ni and Au for solder and wirebond applications. QFPCB Ceramics offers both electroless and electrolytic plating options, as well as a variety of thin filmed variations.

HTCC is a popular material choice for hermetic packaging due to its desirable electrical properties, high mechanical strength and good thermal conductivity. QFPCB Ceramics manufactures its proprietary HTCC blend which allows for hermetic straight through vias and dense metal interconnects. QFPCB Ceramics’ HTCC packages are most commonly used in military, aerospace, medical device and high temperature applications.

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.

Types of Co-Fired Ceramic Fabrication

Characteristic	LTCC	HTCC
Sintering Temperature	Below 900°C	1500 ~ 1600°C
Conductive Materials	Au, Ag, Cu (high conductivity, low melting point)	Alumina, AlN, and other ceramic materials sintered with refractory metal conductors (Mo, W, Mo, Mn)
Embedding of Passive Elements	Can embed resistors, capacitors, and inductors	Does not embed passive elements, uses multilayers
Application	Widely used for RF, microwave, and millimeter-wave devices	High-power microassembly circuits
Advantages	Embedding passive elements reduces module size, cheaper	High structural strength, high thermal conductivity, good chemical stability, high wiring density, suitable for high-performance processors
Disadvantages	Lower sintering temperature limits some applications, lower structural strength compared to HTCC	High firing temperature limits material selection, low conductivity of materials can lead to signal delays

QFPCB has 15 years of experience in the field of HTCC Ceramic PCB production, choose QFPCB, you will get a reliable supplier in China. Contact us today for your HTCC ceramic solutions.

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, QFPCB can support a wide range of production volumes.

QFPCB 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.

QFPCB has 15 years of experience in the field of LTCC Ceramic PCB production, choose QFPCB, you will get a reliable supplier in China. Contact us today for your LTCC ceramic solutions.