LPCVD Nitride – Low pressure chemical vapor deposition nitride

Chemical formula of deposited film: Si3N4

Low pressure chemical vapor deposition is a process that uses heat to initiate a reaction of a precursor gas on a substrate. It is performed at low pressure to decrease unwanted gas phase reactions with the surface of the wafer and the result of this process is high uniformity wafers that are easy to reproduce.

LPCVD nitride is performed in a quartz tube reactor and undergoes a standard chemical vapor deposition process, performed in a vacuum. After loading the wafers into the reactor, the tube evacuates to a low pressure between 10mTorr and 1 Torr, depending on the wafer size and customer specifications.

Once the wafers are under vacuum, the furnace heats up. The temperature inside the system can vary between 425°C and 900°C, depending on the temperature needed for the precursor gas to begin to decompose. After reaching the correct temperature, the system releases gas into the tube to react with the wafers and create a film on the substrate surface.

Once the wafers have the correct film thickness and density, excess gas pumps out of the system and the furnace is moves back to standard room pressure and temperature.

SVM Sample LPCVD Nitride specifications:

SVM offers LPCVD nitride films at different stress levels.

Thickness: 500Å – 4,500Å
Refractive index: 1.95 – 2.05
Film stress: 800MPa Tensile Stress.
Wafer diameter: 50mm300mm.

Thickness:  50Å – 2µm.
Refractive index:  2.20 +/- 0.02
Film stress:  <250MPa Tensile Stress.
Wafer diameter:  50mm300mm.

Thickness: 50Å – 2µm
Refractive index:  2.30 +/- 0.05
Film stress:  <100MPa Tensile Stress.
Wafer diameter:  50mm300mm.


Benefits of LPCVD Nitride:

  • High chemical resistance to acids, bases, salts, molten metals
  • High resistivity
  • Good resistance to oxidation (to ~1500°C)
  • Great barrier
  • Low etch rate

Common Applications:

  • MEMS devices
  • Passivation/Barrier film
  • Integrated circuits (IC)
  • Hard mask for wet and dry etching

 


Silicon Valley Microelectronics provides LPCVD nitride to fit the unique specifications of each customer. For more information on this process or to request a quote, CONTACT SVM or visit our ONLINE INVENTORY.