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Aluminum Nitride Manufacturing Guidelines
ALUMINUM NITRIDE is made by nitridation of aluminum or by conversion of alumina to aluminum nitride. It is a covalently bonded material and has a hexagonal crystal structure. Because of its resistance to sintering, an oxide forming additive such as Y2O3 is needed to form a substrate.
Aluminum Nitride AlN substrate guidelines for tape casting.
For good quality Aluminum Nitride substrates, it is essential to start with high purity AlN powders. Tape cast thickness up to 1.5 mm can be obtained within one step with optimized slurry.
Typical Composition of tape-casting Aluminum Nitride slurry
|
Weight (g) |
Volume % |
| 1-1.5 micron powder |
100 |
34.1 |
| Y203 |
3 |
0.7 |
| Mek / ETOH Azeotrope |
38.9 |
52.6 |
| Beycostat C213 * |
0.5 |
0.5 |
| PVB |
5.4 |
5.4 |
| PE Glycol |
3.3 |
3.2 |
| DB Phtalate |
3.3 |
3.5 |
*Distributed by CECA France
| De-airing: |
|
0.15 atm, 30 minutes, 20°C. |
| Doctor blade tape casting |
|
Thickness: |
1.5 mm |
|
Speed: |
1m/minute |
|
Drying time: |
180 minutes in air at 20°C |
| Dry tape characteristics: |
|
Thickness: |
0.94 mm |
|
Density: |
1.88 |
| Binder removal: |
|
Heating in air between 150°C and 500°C. Above 650°C oxygen contamination will occur. |
| Sintering: |
|
Aluminum Nitride sintering must be conducted in dry nitrogen atmosphere. Expected shrinkage approximately 18%.
NOTE: At room temperature, thermal conductivity of Aluminum Nitride Ceramics is independent of AlN grain size or number of grain-boundries, but, is controlled by the internal structure of the grains, such as the degree of oxidation (Oxygen contamination). |
Recommended conditions:
| Heating rate: |
300°C/hr |
| Temperature: |
1820°C 1 to 3 hr |
| Pressure: |
1 to 10 atm |
| Holder: |
BN, BN coated alumina, or BN coated graphite |
| Cooling rate: |
100°C/hr to 1200°C and then at 300°C/hr |
This Aluminum Nitride manufacturing procedure should yield products with:
- High thermal conductivity
- High electrical resistivity
- Low dielectric loss
- High electrical breakdown voltage
Aluminum Nitride applications include substrates which require good thermal conductivity and heat sinks for semiconductor devices, power modules, mobile communications and multichip modules.
Aluminum Nitride technical related Web sites: