LTCC low temperature co-fired ceramics for high frequency Microwave Filter,sensor,Vacuum Electronics

Coraynic Technology Limited is a professional and reliable LTCC/HTCC ceramic material, 

LTCC (low temperature co-fired ceramics) represents a multilayer ceramic substrate that is co-fired with a low resistance internal circuit made of a metal such as Ag or Cu, at temperatures lower than the melting points of this metal (less than 1,000°C). It can be defined as a way to produce multilayer circuits with the help of single tapes, which are used to apply conductive, dielectric, and/or resistive pastes.

LTCC is a multilayer ceramic technology with excellent dimensional accuracy, high density, high frequency, and reliability offering excellent RF and microwave performance characteristics. Its low sintering temperature (approximately 900°C) allows co-firing with highly conductive metals such as silver and gold.

for moderate firing temperatures. The LTCC process is similar to the thick film hybrid process employed for multilayer ceramic capacitors and chip inductors. The moderate firing temperature level below 900 °C is achieved by mixing alumina and glass as the main ingredients of the ceramic tape, the so-called green sheets. This permits the co-firing with highly conductive material (silver) for the electrodes.LTCC also supports the creation of buried components and thus contributes to miniaturization.

LTCC design rule size

heat sink array

When designing high-frequency signal lines, you can achieve good shielding by placing ground holes in parallel on both sides. As shown below,
The through-holes overlap and the holes in the upper layer can be as small as 0.05mm from the holes in the next layer.

Production Process

Tape casting

LTCC producers usually use tapes shipped on a roll.

Slitting A tape is unrolled and cut into individual pieces. For this purpose,

Via holes punching (Punching machines)

Vias may be punched or drilled with a laser.

Via filling (P-series) in LTCC production

Vias can be filled with a conventional thick film screen printer or an extrusion via filler.

Conductive lines printing (P-series screen printer)

Cofireable conductors etc are printed on the green sheet using a thick film screen-printer. The screens are standard (250 – 400) emulsion or foil-type thick film screens.
Stacking

Opposite to the process where each layer is placed in turns over tooling pins or where some processors use heat pliers to fix the sheets in turns one on top of the other,

Lamination (TPR-series, ILS-series) in the process of LTCC production

There are two possibilities of laminating the tapes in the process of LTCC production. The first one is uniaxial lamination; the tapes are pressed between heated plates at 70°C, 200 bar for 10 minutes (typical values).

This method requires a 180° rotation after half the time. The uniaxial lamination could cause problems with cavities/windows. This method causes higher shrinking tolerances than isostatic lamination.

The main problem is the flow of the tape; which results in high shrinkage tolerances (especially at the edge of the part) during the firing and varying thickness of single parts of each layer (it causes serious problems on the high frequencies sector). A suitable press would be our TPR series.

The second way is to use an isostatic press. The stacked tapes are vacuum packaged in foil and pressed in hot water (temperature and time are just the same as using the uniaxial press). The pressure is about 350 bar. We recommend our ILS-series model.

Cutting into individual pieces

After laminating, the parts are usually cut into individual pieces. For this purpose, our manual or automatic CM-series model-cutting machine can be used.
re dicing saw, which holds tight outside dimensional tolerances and allows high-quality edges.

Cofiring

Laminates are fired in one step on a smooth, flat setter tile.

Application

they are widely used as vehicle-mounted circuit boards which have high reliability, even in integrated electro-mechanical type applications. Also, Murata utilizes its RF technology to realize built-in inductors and capacitors for communication applications, thus contributing to the realization of more compact and lower communication modules.