Composite Powder for Low Temperature Cofired Ceramics

Composite material blended with glass and ceramic powder

Composite Powder for Low Temperature Cofired Ceramics (LTCC) can be fired at 870 to 900°C. This allows the use of gold or silver paste, which offer high electrical conductivity, for the inner layer conductor—resulting in circuit substrates with excellent electrical properties.

Properties
Application Examples
High-Frequency Dielectric Properties of MLS-63

Properties

MLS-25M: Vitreous material with a low coefficient of thermal expansion and low dielectric constant.
MLS-25E: Vitreous material with a dielectric constant of less than 4 and a low dielectric constant.
MLS-41: Devitrifiable material with a high dielectric constant.
MLS-23K: New product with a low dielectric constant and low dielectric loss tangent.
MLS-63: Devitrifiable material with high mechanical strength and low dielectric loss.

Properties/Glass code			MLS-25M	MLS-25E	MLS-41	MLS-23K	MLS-26	MLS-63
Bending strength		MPa	157	125	250	150	320	400
Dielectric constant	1MHz, 25℃		4.9	3.9	17.0	3.9	7.1	8.0
Dielectric constant	15GHz, 25℃		4.8	3.9	19.0	4.0	6.7	7.9
tan δ	1MHz, 25℃	×10^-4	25	5	20	5	4	5
tan δ	15GHz, 25℃	×10^-4	47	21	50	15	58	11
Coefficient of thermal expansion	30～380℃	×10^-7/K	42	60	84	65	58	87
Density*		×10³kg/m³	2.52	2.29	4.36	2.24	3.02	3.52
Transformation point		℃	500	500	700	525	625	725
Volume resistivity Log ρ	150℃	Ω･cm	13.5	>14	-	>13.8	12	>14
Thermal conductivity		W/m･K	1.9	1.7	3.1	1.7	3.9	4.1
Particle size	D₅₀	μm	3.3	3.5	1.1	1.0	2.6	1.6
Particle size	D_max	μm	20	20	10	15	15	10
Glass type			SiO₂･B₂O₃		Nd₂O₃･TiO₂･SiO₂	SiO₂･B₂O₃	SiO₂･CaO･Al₂O₃

Powder theoretical density

Application Examples

Casting and Printing
Glass-ceramic powder, binder resin, solvent, and plasticizer are thoroughly mixed and cast into a 50-300μm thick green sheet using the doctor blade method. Individual sheets are cut into appropriate sizes from the green sheet and punched with via holes and then screenprinted with a circuit pattern.
Lamination
Green sheets are laminated at 50-100°C and under 10-35 MPa pressure.
Firing
Firing is carried out in the air. [Fig. 1]