Glass Substrates for High-frequency Circuit Boards 

Glass Substrates for High-frequency Circuit Boards

Circuit board with reduced transmission loss at higher frequencies

What are High-frequency Circuit Boards?

The type of PCB which is used in applications involving high-frequency signal transmission between objects

High-frequency Signal
周波数:1GHz以上

High-frequency:higher than 1 GHz

Bandwidth: less than 1m

Applications

5G

5G

3.6~6GHz
28GHz

Mobile

通信端末

Autonomous car

自動運転

79GHz

IoT

IoT
Disadvantage

・Easily attenuated by transmission loss

What is transmission loss in HF?

Attenuation per unit-length of high frequency signals

transmission loss
  • Dielectric loss

    The loss that occurs when an electromagnetic wave propagates through a dielectric substrate

  • Conductor loss

    The losses of circuit resistance and skin effect*

In order to improve transmission loss, it is important to work on the material and the wiring structure

* The skin effect is that alternating current tends to avoid travel throughthe center of a solid conductor, limiting itself to conduction near the surface.

Comparison with Substrate Materials

Comparison with Substrate Materials

Because of its low thermal expansion, glass has superior dimensional stability and superior high frequency transmission characteristics.

  Ref.Sillicon Glass Ceramics Organic
Alkali-free Quartz Al2O3 AlN FR-4 PTFE
Coefficient of thermal expansion
×10-6/K
3.9 3-4 0.5 7 4-5 20 7
Permittivity
εr
12 5-7 4 <10 9 4.5 2.1
Loss tangent
tanδ
- 0.002 <0.0005 <0.0005 0.0005 0.005 0.0002
Chemical resistance -            
Features - Excellent high frequency
transmission characteristics
Heat dissipation Low cost Excellent high frequency
transmission characteristics

Good    Average    Poor

Reference values

Reference values

Comparison with Dielectric Loss of Substrate Materials

周波数

The dielectric loss of quartz
glass is about 1/6 of PTFE *

*on 79GHz Band

■ Simulation result on
micro-strip-line

■ Permittivity/Loss tangent
● PTFE
(2.6 / 0.0007)
● Alumina
(9.8 / 0.0002)
● Quartz
(3.78 / 0.0001)

Design Specs

Standard Design

Size mm 300 × 300
Thickness (A) μm 200-600
Copper Thickness (B) μm 5 10 20
Line(C)
μm
10 10 10
Space(D)
μm
20 25 50
断面図

Cross-section

Through-hole Filling

【Actual value】

Via’s Top Diameter (E) 30 μm/Glass Thickness (F) 200 μm

ガラス貫通穴横断面図

Through-glass via cross-section

Substrate Material

Alkali-free glass / Quartz glass / Borosilicate glass / Soda lime glass / Sapphire glass

These dimensions are for reference only. Please contact us with your exact specifications.

Plating Examples

Wire Plating

Plating into Through-holes

 

Cross section

Through-glass via cross-section

Application Examples

Purpose Applications Fields
Conduct electricity Glass interposer (TGV) Semiconductors, Electronics, Electrical appliances,Telecommunications,Industrial equipment, Medical
High frequency substrate,
Communication antenna
Semiconductors, Electronics, Electrical appliances,Telecommunications,Industrial equipment, Medical

Production Flow Chart

Ebinax has an integrated production system from material procurement to dicing glass substrate.

  • Discussion / Order
  • Material procurement
  • Glass through-hole processing
  • Plating (electrode formation)
  • Polishing/Dicing
  • Delivery
納品までの流れ

※Please contact us with your request.

Ebinax’s process leads to lower management costs and shorter lead times.

Please contact us if you have any questions.

[TEL] +81-3-3742-0107  [FAX] +81-3-3745-5476