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Working with Sapphire

Sapphire Semiconductor Wafer

Working with Sapphire

Sapphire is increasing in use in a variety of manufacturing applications. Synthetic sapphire can sometimes be carefully grown into desired shapes and sizes, but in most cases it must be machined to specifications to be used properly. We at Innovative Fabrication have many years of experience machining sapphire, so we will manufacture components to very precise specifications as needed.

What Is Sapphire?

Sapphire is a clear, crystalline form of aluminum oxide. Natural sapphire contains trace amounts of iron and titanium, which sometimes give sapphires the blue color that they are known for. Some sapphires may contain differing quantities of titanium, chromium, and iron, which may affect the coloration, though. Natural sapphires generally have small crystals and naturally occurring impurities, so natural sapphires are rarely used in application other than jewelry making.

Synthetic Sapphire

Synthetic sapphire is produced in a laboratory by melting aluminum oxide and then using a seed to foster crystal growth. The environment is carefully controlled to prevent impurities. Certain methods can be used to control the shape into which the sapphire grows. However, the methods that yield sapphire with the highest optical qualities (the Kiropolous, Czochralski, or HEM methods) only produce blob-like crystals which must be cut and machined in order to be useful.

Sapphire Applications

Sapphires can be used in a variety of application, including but not limited to:
  • Heater substrates
  • Spray nozzles
  • Barcode scanner windows
  • Optical wedges for spectroscopic diagnostic instruments
  • Semiconductor wafer carriers
  • Bearings
  • Blades
  • Tubes
  • Optical concentrator arrays
  • Watch faces
  • Optical lenses

Advantages of Using Sapphire

Sapphire is one of the hardest materials, with only diamond and silicon carbide being harder. Sapphire has an extremely high melting point, and is capable of enduring temperatures up to about 1600 degrees Celsius without any alteration in stability. Sapphire has a low coefficient of thermal expansion and high conductivity at cryogenic temperatures. Sapphire also has excellent optical properties. These qualities make sapphire far superior to glass and most other materials, especially for use in extreme conditions.

Lapping and Polishing Sapphire

After growing, sapphires are cut to desired angles and specifications. For many applications, sapphires are cut into wafers. After wafers are sliced, they must be lapped to the desired thickness and polished. Innovative Fabrication is experienced at lapping sapphires to exacting specifications for flatness, dimension, roundness, and wedge. Sapphires are polished after the lapping process is completed to reach the final desired thickness and surface finish.