Substrate

All circuit designs begin with the proper choice of substrate.  Factors such as dielectric constant, loss tangent, thermal dissipation and cost all factor into the proper choice of material.  DITF offers our services on all substrate materials — Al2O3 (Alumina — 99.6% as-fired or polished), BeO, AlN, Fused Silica and Barium Titanate all provide various properties of interest to the designer.

Common processing sizes (L + W)

Alumina, Beryllia, AlN – 3.75” x 4.5”, 3.0” 2, 2.25” 2, 2.0” 2, 1.0” 2

-Thickness Range - .003" - .080"

Fused Silica, Sapphire, Ferrites & Garnets - 3.0” 2, 2.25” 2, 2.0” 2, 1.0”2

-Thickness Range - .003” - .025”


Layout Templates

(Right Click and Chose "Save as")

Standard Herman
(3.75” x 4.5”) layout
(.dwg file) or (.pdf file)		 Standard
3.0”x3.0" layout
(.dwg file) or (.pdf file)

 

Common Substrates and Properties

Material Surface Finish
& Roughness		 inch/
inch		 g/cm3
 KX10-3 10-6/°C (@25°C)
w/m°K		 kV/
mm		 Ωcm 1MHz/
10GHz 		1MHz/
10GHz
A B C D E F G H I
Alumina
>95.5%

Low to medium power DC/RF or Microwave
circuitsusing Si or GaAs Ics
Fired
± 3µ"
± 0.003
3.88
90
7-8.3
~35
~23
<1014
9.9/
9.6
.001/
.002
Pol.
< 1µ"
0.0005
Aluminum Nitride

High-power DC/RF/Microwave
circuits using Silicon and GaAs Ics.
Lapped
12"-20µ"
0.001
3.30
59
4.6
170
~15
<1013
8.5-9.2
/na
.004/
na
Pol.
< 2µ"
0.0005
Berylium
Oxide




High-power DC/RF/Microwave circuits
using Silicon or GaAs Ics. High-power termination.
Fired
10"-20µ"
± 0.005
2.85
35
9
265
-
< 1015
6.6/
6.7
.003/
.0009
Pol.
< 4µ"
± 0.0005
Fused
Silica





Microwave/Millimeter-wave circuits requiring
extremely low loss or low CTE.
Pol.
60/40
0.0005
2.20
25
0.55
1.38
30
<1010
3.82/
na
-
Lapped
7 -12µ"
0.0005
Sapphire



Millimeter-wave/optical circuits with special
electrical or mechanical requirements.
Pol.
<1µ"
0.0005
3.97
60
5.3
~40
-
<1017
9.3*-11.4
/na
.00086-.
0003*
Lapped
10"-20µ"
0.0005
Ferrite





RF/Mircrowave circulators/isolators
Pol.
10µ
0.001
-
-
-
-
-
< 1017
11.3/
15.4
.0002-
.0015

*Varies with crystal orientation. A Plane / C Plane

A: Camber B: Density C: Flexural Strength D: Thermal Expansion E: Thermal Conductivity
F: Dielectric Strength G: Volume Resistivity H: Dielectric Constant I: Loss Tangent

 

Holes and Machined Features

Property Value and Tolerances Comments
Maximum Thickness
.060"
Thicker materials require factory consultation
.003"
CO2 beam width = .003", use .006" min radius to change cut direction
Smallest Feature
0.6:1(ratio) minimim diameter
to material thickness
Front to Back Taper
10 - 15% of material thickness
Includes bell effect at entrance
Via Hole for plated
thru connection
0.8:1 (ratio) hole diameter to material thickness
Measured at exit, account for metal anulas on circuit side
Via Hole filled
0.7:1 (ratio) hole diameter to material thickness
Account for metal anulas on circuit side
Feature Size Tolerance
± .002"
Non-Commulative
1X material thickness
Not less than .020"
1X material thickness
Not less than .020"
± .003"
All cutouts require a .003" pullback of backside metal.
Diamond Sawing
± .001" min
± .002" Standard