The sensor, English name transducer, is a detection device, can feel the measured information, and can feel the information, according to the law must transform into electrical signals or other information in the form of output required to meet the information transmission, processing, storage, display, record and control requirements.
Classified according to the manufacturing process:
Integrated sensors are fabricated using standard silicon based semiconductor integrated circuit technology. Usually part of the circuitry that will be used for preliminary processing of the signal to be tested is also integrated on the same chip, such as the MEMS sensor, which is now developing vigorously.
Thin film sensors are formed by depositing films of sensitive materials on a dielectric substrate (substrate). A part of the circuit can also be fabricated on the substrate when using the mixing process.
Thick film sensors are made from the slurry of the corresponding material and coated on ceramic substrates. The substrate is usually made of Al2O3 and then treated with heat to form a thick film.
Ceramic sensors are produced using standard ceramic processes or some of their variants, processes (sols, gels, etc.). After the proper preparatory operation has been completed, the formed elements are sintered at elevated temperatures.
There are many common characteristics between the two processes of thick film and ceramic sensors. In some ways, thick film process can be considered as a variant of ceramic technology.
Select it from the sensor sensitivity, frequency response, linearity, stability and accuracy of these aspects to consider, the stability and the substrate material have a great relationship, in front of several major manufacturing process, from the stability in terms of words, non ceramic circuit board so the most suitable sensor is. The stability of ceramic materials is quite good. As long as the manufacturing process can pass, the ceramic circuit board is undoubtedly much better than other PCB.
Now the best ceramic circuit board manufacturing process, should be the LAM technology, the technology of laser rapid activation of metal (Laser Activation Metallization, referred to as LAM Technology), the use of ceramic and metal ion beam of high-energy laser, so that the two are firmly combined.
But the current domestic manufacturers or by small and medium sized sensor, there are still many in the use of thin film technology, using the FR-4 substrate, the service life is not long, poor stability and bad environment encounter a little more, direct strike. It takes a lot of effort to keep sensors in line with international standards.
The sensor industry to update iteration and progress, but certainly around a wide range of applications of ceramic circuit board, as far as I know, the domestic LAM technology capable of producing ceramic circuit board, only Adams Litong ceramic circuit board technology, LAM ceramic circuit board to produce features:
1. higher thermal conductivity: alumina ceramic thermal conductivity: 15~35 W/m / K AlN ceramic thermal conductivity: 170~230 W/m • K, copper substrate thermal conductivity of 2W/m = K
2., the thermal expansion coefficient of ceramic chip and the thermal expansion coefficient is close to, will not have too large deformation leads to changes in temperature line welding, stress and other issues!
3., more firmly and lower resistance metal film: the metal layer and ceramic substrate bonding strength is high, the metal layer of good conductivity, the current through the heating small;
4., good insulation: breakdown voltage of up to 20KV/mm;
The thickness of the 5. conductive layer is customized at 1 m to 1mm: the copper thickness can be customized, and the contribution to the MEMS is not small.
6. high frequency loss, high frequency circuit design and assembly can be carried out with little dielectric constant,
7. can be high-density assembly, line / spacing (L/S) resolution can reach 20 m, so as to achieve the equipment short, small, light and thin;
In addition to the above characteristics, LAM ceramic circuit board, pass also has no organic ingredients, long service life, the copper layer contains no oxide layer, can be used for a long time in a reducing atmosphere, you can even do a three-dimensional three-dimensional wiring substrate.
In the end, the sensor still need ceramic circuit board, at present in developed countries has been widely used in our country at present, do not restrict the development of technology, sensor circuit board upgrading, will have to see the major manufacturers, GoerTek, UOB these Chinese leading play a leading role, manufacturers of technological innovation, in order to expand strong, sensor industry in China to catch up with the world pace.