LTCC

LTCC - Low Temperature Co-fired Ceramic

LTCC (Low Temperature Co-fired Ceramic) is a multilayer capable substrate technology 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. The excellent mechanical and electrical properties of LTCC substrates, combined with the ability to embed passive components, offer superior RF performance and device miniaturization for high frequency applications.

About LTCC

LTCC features

LTCC properties

About LTCC

LTCC process flow

The multilayer technology allows for the parallel stacking of up to more than 20 layers.

The excellent mechanical and electrical properties of LTCC substrates, combined with the ability to embed passive components and to apply fine line patterning, offer superior RF performance and device miniaturization for high-frequency applications.

Further features like the application of heat sinks, frames and nail head pins by brazing allow for hermetic and highly complex packages.

Quality performance testing and assurance

In-process and final inspection procedures include:

  • Automated optical inspection using a MIDAS Vision AOI system
  • Electrical inspection using an ATG flying probe test system
  • Visual inspection
LTCC features

LTCC dimensional capabilities

Index

Description

Specification

A

Line width

80 µm

B

Line to via coverpad spacing

100 µm

C

Line spacing

80 µm

D

Via pitch
* Depends of number of vias and vias per row
# Smaller sizes on request

300 µm (*, #)

E

Line to edge spacing

200 µm

F

Via to edge spacing

300 µm

G

Pad to edge spacing

200 µm

H

Via coverpad

I + 50 µm

I

Via diameter

≥ 100 µm

Cavities and windows

Index

Description

Specification

J

Cavity width/length

# Smaller sizes on request

≥ 800 µm (#)

 

K

Cavity bottom thickness

2 layers

L

Distance between cavities 

# Smaller sizes on request  

≥ 2 mm (#)

 

M

Cavity depth

Design related

Integrated passive components


Capacitors

  • Embedded
  • Multilayer
  • Up to 20 pF/mm2


Inductors

  • Planar
  • 3D


Resistors

  • Trimmable post-fire (7 decades)
  • Buried co-fire

Brazing operations


Metal plates

  • Housing
  • Heatsinks / thermal management


Frames

  • Hermetic packages
  • Shielding


Pins

  • Connectors
  • Board connection

Mechanical processing


Laser cutting / scribing in green state 
 

  • Accuracy: ± 0.130 mm


Machining after firing

 

  • Accuracy: ± 0.130 mm
LTCC properties

RF performance

  • Good impedance control
  • Low to medium k-values
  • High conductive metals
  • Low dielectric losses up to 120 GHz

Electrical properties of microwave materials

Name

 

LTCC
DuPont 951

LTCC
DuPont 9K7

LTCC
Ferro L8

Thick film on 
Al2O3 (96%)

Type

 

Dielectric layer

Dielectric layer

Dielectric layer

Dielectric substrate

Thickness

µm

 (40), 98, 135, 204

98, 196

88, 135, 176

250, 380, 500, 630,1000

Electrical properties

 

 

 

 

 

Dielectric Constant 

10 GHz

7.5

7.1

7.2

9.8

Dissipation Factor (tan δ)

10 GHz

0.006

0.001

0.002

0.0006

Dielectric Strength

kV/mil

>1

>1

>1

>1

Mechanical properties

 

 

 

 

 

Youngs Modulus

GPa

120

145

113

340

Felxural Strength

MPA

320

230

275

400

Fired Density

g/cm³

3.1

3.1

3.1

3.8

Thermal properties

 

 

 

 

 

CTE

ppm/K

5.8

4.4

5.8

6.8

Typ. Thermal Cunductivity
(bulk material without vias)

W/mK

4

4.6

>3

24

Downloads

LTCC substrates (PDF)